Colour Forming Components and Compositions Field of the Invention

The present invention relates to components and compositions, in particular components and compositions for forming an image on or within a substrate.

Background of the Invention

In-line digital printing is a process known for the formation of greyscale, single- coloured (monochromic), or multi-coloured images on or within substrates. Radiation from a laser source(s) effects laser-reactive components in compositions applied on or incorporated within substrates such that they change colour upon application of the radiation. However, problems arise in that when using these laser-reactive components, access to a full colour gamut and the full range of primary colours required to form multi-coloured images is difficult to achieve.

Diacetylene compounds are known laser-reactive components. WO 2012/114121 , WO 2013/68729, WO 2011/121265, WO 2010/112940 and WO 2010/001171 disclose such components.

There is therefore a desire to provide laser-reactive components and compositions for the formation of an image on or within a substrate that can provide a broad colour gamut for in-line digital printing via laser excitation, enabling real-time marketing and personalisation response capabilities for users. In order to achieve this, it is important to have compositions that have components able to form stable predictable colours upon application of radiation or other stimuli.

Summary of the Invention

According to a first aspect of the present invention there is provided a deactivatable component capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an applied transition stimulus, wherein the deactivatable component can be deactivated, either before or after transitioning, by application of a deactivation temperature, such that subsequent transitioning cannot occur.

According to a second aspect of the present invention, there is provided a composition comprising a deactivatable component capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an applied transition stimulus, wherein the deactivatable component can be deactivated, either before or after transitioning, by application of a deactivation temperature, such that subsequent transitioning cannot occur.

According to a third aspect of the present invention there is provided a substrate comprising a composition applied to or incorporated within, the composition comprising a deactivatable component capable of transitioning from a non- coloured state to a coloured state, the transition being effected by the application of an applied transition stimulus, wherein the deactivatable component can be deactivated, either before or after transitioning, by application of a deactivation temperature, such that subsequent transitioning cannot occur.

According to a fourth aspect of the present invention, there is provided a method of forming a substrate, the method comprising applying a composition to or incorporating a composition within a substrate, the composition comprising a deactivatable component capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an applied transition stimulus, wherein the deactivatable component can be deactivated, either before or after transitioning, by application of a deactivation temperature, such that subsequent transitioning cannot occur.

According to a fifth aspect of the present invention, there is provided a method of forming colour on or within a substrate comprising a composition applied to or incorporated within, the composition comprising a deactivatable component capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an applied transition stimulus, wherein the deactivatable component can be deactivated, either before or after transitioning, by application of a deactivation temperature, such that subsequent transitioning cannot occur, and wherein the method comprises applying to the composition on or within the substrate, the applied transition stimulus and the deactivation temperature as required to develop a coloured state of the deactivatable component of the composition.

According to a sixth aspect of the present invention, there is provided a method of forming an image on or within a substrate comprising a composition applied to or incorporated within, the composition comprising a deactivatable component capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an applied transition stimulus, wherein the deactivatable component can be deactivated, either before or after transitioning, by application of a deactivation temperature, such that subsequent transitioning cannot occur, and wherein the method comprises applying to the composition on or within the substrate, the applied transition stimulus and/or deactivation temperature as required to selectively develop the non-coloured and/or the coloured states of the deactivatable component at localised positions of the composition, and thereby create an image on or within the substrate.

According to a seventh aspect of the present invention, there is provided a use of a deactivatable component or a composition comprising the deactivatable component in the formation of colour on or within a substrate, the deactivatable component being capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an applied transition stimulus, wherein the deactivatable component can be deactivated, either before or after transitioning, by application of a deactivation temperature, such that subsequent transitioning cannot occur..

According to an eighth aspect of the present invention, there is provided a use of a deactivatable component or a composition comprising the deactivatable component in the formation of an image on or within a substrate, the deactivatable component being capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an applied transition stimulus, wherein the deactivatable component can be deactivated, either before or after transitioning, by application of a deactivation temperature, such that subsequent transitioning cannot occur. According to a ninth aspect of the present invention, there is provided a substrate having applied thereon a plurality of discrete layers, wherein at least one of the discrete layers comprises a deactivatable component capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an applied transition stimulus, wherein the deactivatable component can be deactivated, either before or after transitioning, by application of a deactivation temperature, such that subsequent transitioning cannot occur; and wherein at least one of the discrete layers comprises one or more additional component capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an additional applied stimulus or additional temperature; wherein, if formed, the coloured state of the deactivatable component and the one or more additional component are different in colour, and the discrete layer comprising the deactivatable component is a different layer to the discrete layer comprising the one or more additional component.

According to a tenth aspect of the present invention there is provided a method of forming a substrate having applied thereon a plurality of discrete layers applied thereon, wherein at least one of the discrete layers comprises a deactivatable component capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an applied transition stimulus, wherein the deactivatable component can be deactivated, either before or after transitioning, by application of a deactivation temperature, such that subsequent transitioning cannot occur; and wherein at least one of the discrete layers comprises one or more additional component capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an additional applied stimulus or additional temperature; wherein, if formed, the coloured state of the deactivatable component and the one or more additional component are different in colour, and the discrete layer comprising the deactivatable component is a different layer to the discrete layer comprising the one or more additional component; and wherein the method comprises applying to a substrate the plurality of discrete layers.

According to an eleventh aspect of the present invention, there is provided a method of forming colour on a substrate having applied thereon a plurality of discrete layers, wherein at least one of the discrete layers comprises a deactivatable component capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an applied transition stimulus, wherein the deactivatable component can be deactivated, either before or after transitioning, by application of a deactivation temperature, such that subsequent transitioning cannot occur; and wherein at least one of the discrete layers comprises one or more additional component capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an additional applied stimulus or additional temperature; wherein, if formed, the coloured state of the deactivatable component and the one or more additional component are different in colour, and the discrete layer comprising the deactivatable component is a different layer to the discrete layer comprising the one or more additional component; and wherein the method comprises applying to the substrate, the applied transition stimulus and deactivation temperature, and additional applied stimulus or additional temperature as required to develop a coloured states of the deactivatable component and one or more additional component.

According to a twelfth aspect of the present invention, there is provided a method of forming an image on a substrate having applied thereon a plurality of discrete layers, wherein at least one of the discrete layers comprises a deactivatable component capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an applied transition stimulus, wherein the deactivatable component can be deactivated, either before or after transitioning, by application of a deactivation temperature, such that subsequent transitioning cannot occur; and wherein at least one of the discrete layers comprises one or more additional component capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an additional applied stimulus or additional temperature; wherein, if formed, the coloured state of the deactivatable component and the one or more additional component are different in colour, and the discrete layer comprising the deactivatable component is a different layer to the discrete layer comprising the one or more additional component; and wherein the method comprises applying to the substrate, the applied transition stimulus and/or deactivation temperature, and additional applied stimulus or additional temperature as required to selectively develop the non- coloured and/or the coloured states of the deactivatable component and one or more additional component at localised positions, and thereby create an image on or within the substrate.

Detailed Description of the Invention

The intention of the present invention is to provide a laser-reactive component and composition that is capable of providing colour or an image on or within a substrate using a laser source(s) to manipulate colour changes in the components of the laser-reactive composition at localised positions so as to create single- or multi-coloured images having any desired colour.

The present invention is of particular use in in-line printing, and allows compositions to be prepared with components that can respond to radiation or other stimuli to generate predictable colours for image formation. The deactivatable component of the present invention may therefore have use independently or in combination with other colour-forming compounds, depending on desired use. A broad colour gamut can therefore be achieved using these laser-reactive components. It has been surprisingly and advantageously found that the deactivatable components of the present invention can be deactivated either before or after transitioning to a coloured state. In contrast, such deactivation is not possible for the diacetylene compounds disclosed in WO 2012/114121 , WO 2013/68729, WO 2011/121265, WO 2010/112940 and WO 2010/001171.

"Non-coloured state" and like terms as used herein, refers to the natural state of a deactivatable component before the applied transition stimulus is applied to it. The non-coloured state of a component may be white, off-white or colourless i.e. clear, or has reduced or low visible colour, i.e. is paler in colour (a lighter shade or less intense colour) than a coloured state of the same colour. Alternatively, the natural state (non-coloured state) of a component may possess an initial colour which will change following application of the applied transition stimulus to a more intense colour (coloured state) or a different colour. It will therefore be appreciated by a skilled person that, in the natural state, the component may often appear to display a colour, but that when compared with a coloured state of the same component, it will be paler in colour, i.e. less intensely coloured, or a different colour. It will be appreciated that, when the non-coloured state of a component is colourless, any underlying colour of the substrate on which the component is applied or incorporated within will be visible.

"Coloured state" and like terms as used herein, refers to the state of a deactivatable component in which the component displays a colour, i.e. is substantially or highly coloured, in the visible spectrum and to a human eye. The "coloured state" will be more intensely coloured than the "non-coloured state" of the same compound. This may be a more intense colouration of the same colour, but may also be a more intense colouration of a different colour to that of the non-coloured state as discussed above. In relation to the term "coloured state", the singular encompasses the plural and vice versa. For example, although reference is made herein to "a" coloured state, the term encompasses one or more coloured states. Typically, the deactivatable component has first and second coloured states, each of the first and second colour states displaying a different colour. By the term "colour" and like terms as used herein, is meant the colours and hues of the visible light colour spectrum, i.e. red, orange, yellow, green, blue and violet, in addition to magenta, pink, purple, turquoise, brown, cyan and black, and mixtures thereof. Both primary and secondary colours are encompassed, i.e. it will be appreciated by a skilled person that a coloured state of a component may have a primary or secondary colour. In the context of the present invention, the term may also be used to describe differing shades of each of the colours of the visible light colour spectrum, in addition to magenta, cyan, pink, purple, turquoise, brown and black.

"Stable coloured state" and like terms as used herein, refers to the coloured state of a deactivatable component that is stable under ambient conditions, i.e. maintains essentially its colour under ambient conditions. "Ambient conditions" and like terms as used herein, refers to the normal range of conditions of the surrounding environment to which the components are exposed, i.e. the range of temperatures, pressures and atmospheric conditions to which the components are exposed during use, storage and otherwise. This includes solar radiation including electromagnetic radiation of X-rays, ultraviolet (UV) and infrared (IR) radiation. Typically, ambient conditions include a temperature of from 10 to 35 °C, a pressure of from 20 to 100 kPa, and the environment is typically an oxygen-containing atmosphere. It will be appreciated by a skilled person that the required stability of the coloured state of a component will be dependent upon the application for which a substrate having the deactivatable component or composition and therefore the deactivatable component applied to or incorporated within is intended to be used. For example, if the component or composition comprising the component is to be utilised in a laser reactive patch for a disposable item such as a hot or cold beverage container, the required stability of the component of the composition will only need to be for a relatively short period of time, for example, a number of hours, such as 6 to 12 hours, or a number of days such as 3 or 4 days. Whereas, if the component or composition is to be utilised as a laser-reactive component or laser-reactive composition applied on or incorporated within a cosmetic container or outdoor signage, the required stability of the component will be greater, for example, a number of months, or even a number of years for outdoor signage uses. In general however, stable under ambient conditions is meant that when exposed to ambient conditions for at least a number of hours or a number of days, such as for at least two weeks, the coloured state maintains essentially its colour. Preferably, the component will permanently remain in the particular coloured state. Accordingly, it is preferred that the component remains in the particular coloured state for at least 3 days, preferably for at least 4 weeks, more preferably for at least 1 or even at least 2 weeks, and most preferably, for at least 2 months.

"Monochromic" or "single-coloured image" and like terms used herein, refer to an image that is human or machine readable and has a single colour that is visible to the human eye. In the context of the present invention, the non- coloured state can form part of a monochromic image. In particular, when the non-coloured state of a component is non-coloured, i.e. white, off-white or colourless, the non-coloured state can form part of the monochromic image.

"Multi-coloured image" and like terms as used herein, refers to an image that is human or machine readable having multiple colours, i.e. displaying 2 or more colours that are visible to the human eye. In the context of the present invention, the non-coloured state can form part of the multi-coloured image. In particular, when the non-coloured state of a component is non-coloured, i.e. white, off-white or colourless, the non-coloured state can form part of the multi-coloured image.

The term "image" incorporates, but is not limited to: pictures, text, logos, graphics, figures and symbols. The term also encompasses both single- and multi-coloured images. It will be appreciated that in the context of the present invention, for both single- and multi-coloured images, it is the manipulation of the components of the composition that facilitates the formation of an image.

"Transitioning" and "transition" and like terms as used herein, refer to a deactivatable component changing irreversibly from a non-coloured state to a coloured state upon application of the applied transition stimulus. It will be appreciated by a skilled person that this is an intentional transition facilitated by the application of the applied transition stimulus as required to the deactivatable component. The term also encompasses, for example, a deactivatable component changing from a first coloured state to a second coloured state upon application of the deactivation temperature as discussed below. By the term "irreversibly" is meant that once the coloured state of the component has been formed, the coloured states of the components will be stable under ambient conditions.

"Subsequent" or "subsequent transitioning", and like terms as used herein in relation to the deactivatable component, refer to any transition following (taking place after) the deactivation of the deactivatable component. This is an intentional transition, i.e. intentional exposure to radiation or temperature, including UV radiation provided by a germicidal lamp or broadband UV radiation provided by a medium-pressure mercury lamp.

"Printing", "in-line digital printing" or "laser printing" and like terms as used herein, refer to the process of using radiation to achieve colour and form an image on a substrate.

Radiation" and like terms as used herein, refers to energy in the form of waves or particles, and in particular, refers to electromagnetic radiation such as ultraviolet (UV), visible, near-infrared (NIR), and infrared (IR) particle radiation, e.g. alpha (a) radiation, beta (b) radiation, neutron radiation and plasma. It will be appreciated that, in the context of the present invention, a distinction is made between radiation of greater than 400 nm, e.g. near-infrared radiation, which causes vibrational, conductive and radiative excitation to the components upon application and therefore provides a "temperature", and radiation of 400 nm or less (e.g. ultraviolet radiation), or microwave radiation, which does not. In the context of the present invention, the "temperature" applied to the compositions and compounds is intended to include the temperature provided to the compositions and compounds through the application of thermal energy in different conductive, radiative and vibrational forms. As discussed, this may be through application of radiation of greater than 400 nm.

By the term "laser source(s)" and like terms as used herein includes any suitable commercial or non-commercial laser source(s).

"Deactivatable", "deactivated" or "deactivating" and like terms as used herein, refer to the inability of the deactivatable component to undergo any subsequent transition upon exposure to intentionally applied radiation or temperature. This intentionally applied radiation or temperature may be provided by a germicidal lamp, medium-pressure mercury lamp or ultravitalux bulb. It will be appreciated that during deactivation of the deactivatable component, the deactivatable component may transition to another coloured state at the same time. This coloured state will be stable under ambient conditions. For example, the deactivatable component may transition from a first coloured state to a second coloured state upon application of the deactivation temperature. The deactivatable component will be considered "deactivated" if it remain essentially unchanged for at least 1 minute, such as for at least 1 hour. Preferably, the component remains in essentially unchanged for at least 1 day, such as for even 1 week. Most preferably, the deactivatable component remains permanently essentially unchanged.

Without being bound by theory, the present inventors consider that it is the monomer form of the deactivatable component that is being deactivated, i.e. in the non-coloured state, the deactivatable component is present in monomer form and these monomers are ‘deactivated’ upon application of the deactivation temperature, and in a coloured state, it is the residual monomers that have not been polymerised and are still in their non-coloured state (and therefore still have colour-forming ability) that are‘deactivated’.

All references to particular chemical compounds herein are to be interpreted as covering the compounds per se, and also, where appropriate, derivatives, hydrates, solvates, complexes, isomers, tautomers thereof.

The deactivatable component may be selected from any suitable component.

The deactivatable component may be a diacetylene compound, i.e. a compound comprising a diacetylene moiety ( ' c=c-c=c— \ y

The deactivatable component may be a diacetylene compound comprising a protecting group. The deactivatable component may be a diacetylene compound having the following formula (I): wherein x is from 2 to 12, preferably 2 to 10, and more preferably 2 to 8;

L is selected from amide having the formula and an ester having o

the formula: preferably L is an amide having the formula y is from 0 to 10, preferably 0 to 8, and more preferably 0 to 6;

E may be absent or present, and when present, E is selected from NH, O, and CH ₂ ; preferably E is NH; P is a protecting group; and

T is selected from hydrogen, a -(CH ₂ ) _X (CH ₃ ) linear alkyl chain, wherein x is defined as above for formula (I), and -(CH ₂ ) _x -L-(CH ₂ ) _y -E-P, wherein x, y, L, E and P are defined as above for formula (I).

It will be appreciated by a skilled person that the diacetylene compound can be either symmetrical or unsymmetrical, i.e. T is -(CH ₂ ) _x -L-(CH ₂ ) _y -E-P and the values of x, y, L, E and P are the same as those on the other side of the diacetylene moiety (symmetrical), or T is hydrogen, a -(CH ₂ ) _X (CH ₃ ) linear alkyl chain, or -(CH ₂ ) _x -L-(CH ₂ ) _y -E-P and the values of x, y, L, E and P are different to those on the other side of the diacetylene moiety (unsymmetrical). Preferably, the diacetylene compound is symmetrical.

By the term "protecting group" is meant, any cleavable organic chemical moiety that can be cleaved/removed from the diacetylene compound when exposed to certain conditions, including but not limited to: acid, base, heat, hydrogenation, and reduction. Without being bound by theory, it is understood by the present inventors that, in the context of the present invention, the protecting group is cleaved from the deactivatable compound upon exposure to the deactivation temperature. To achieve deactivation, it is not necessary that all of the protecting groups are cleaved (of the monomers and polymer of the diacetylene compound as defined below). The protecting group according to the present invention is therefore cleavable upon exposure to the deactivation temperature, i.e. upon exposure to temperature applied by radiation of a wavelength of greater than 400 nm.

Examples of suitable protecting include, but are not limited to: alkyl and aryl oxycarbonyl groups selected from tert- butyloxycarbonyl (BOC), 2,4- dimethylpent-3-yloxycarbonyl (DOC), dioctyl(((docosa-10,12- diynedioyl)bis(azanediyl))bis(ethane-2, 1 -diyl))dicarbamate (SOC), 9- fluorenylmethyl oxycarbonyl and benzyl oxycarbonyl; benzoyl; carboxy benzyl; and allyloxycarbonyl; cycloalkyls such as cyclododecane and cyclooctane; amide groups such as acetamide and trifluoroacetamide; phthalimide; triphenylmethyl; benzylidene; and p-toluenesulfonyl.

Preferably, P is an alkyl or aryl oxycarbonyl group or a cycloalkyl, more preferably P is selected from tert- butyloxycarbonyl (BOC), benzoyl, carboxy benzyl, cyclododecane, cyclooctane, 9-fluoreny I methyl oxycarbonyl, 2,4- dimethylpent-3-yloxycarbonyl (DOC), and dioctyl(((docosa-10,12- diynedioyl)bis(azanediyl))bis(ethane-2, 1 -diyl))dicarbamate (SOC). More preferably, P is an alkyl or aryl oxycarbonyl group, and most preferably P is selected from tert- butyloxycarbonyl (BOC), 9-fluoreny I methyl oxycarbonyl, benzoyl, carboxybenzyl, 2,4-dimethylpent-3-yloxycarbonyl (DOC), and dioctyl(((docosa-10, 12-diynedioyl)bis(azanediyl))bis(ethane-2, 1 - diyl))dicarbamate (SOC).

The deactivatable component may be a diacetylene compound having the following formula (II): wherein x is from 2 to 8, y is from 0 to 6, and P is selected from tert- butyloxycarbonyl (BOC), benzoyl, 9-fluoreny I methyl oxycarbonyl, carboxy benzyl, cyclodecane, cyclooctane, 2,4-dimethylpent-3-yloxycarbonyl (DOC) and dioctyl(((docosa-10, 12-diynedioyl)bis(azanediyl))bis(ethane-2, 1 - diyl))dicarbamate (SOC).

Preferably, the deactivatable component is selected from di-tert-butyl 2,2'- (tetradeca-6,8-diynedioyl)bis(hydrazine-1 -carboxylate), di-tert-butyl(((docosa- 10, 12-diynedioyl)bis(azanediyl))bis(ethane-2, 1 -diyl))dicarbamate, di-tert-butyl 2,2'-(docosa-10,12-diynedioyl)bis(hydrazine-1 -carboxylate), dibenzyl 2,2'- (docosa-10,12-diynedioyl)bis(hydrazine-1 -carboxylate), N'1 ,N'22- dibenzoyldocosa-10, 12-diynedihydrazide, tert-butyl 2-(pentacosa-10, 12- diynoyl)hydrazine-1 -carboxylate, N 1 , N22-dicyclodecyldocosa-10, 12- diynediamide and di-tert-butyl(((docosa-10,12- diynedioyl)bis(azanediyl))bis(hexane-6, 1 -diyl))dicarbamate.

Diacetylene compounds are well known to a skilled person as compounds capable of forming colour. Typical diacetylene compounds are disclosed for this purpose in WO 2012/114121 , the content of which is incorporated herein by reference. Suitable examples of diacetylene compounds and the synthesis of such are taught in W02009/093028, WO2010/001171 , WO2010/029329, and WO2013/068729, the content of each of which is incorporated herein by reference. Known methods of synthesis of diacetylene compounds include the formation of a reactive acid chloride and subsequent addition of an amine or alcohol, or the formation of a mixed anhydride and subsequent reactions with an amine or alcohol. For the diacetylene compounds disclosed herein, such syntheses include the installation of a protecting group P. Typically, the diacetylene compounds have first and second coloured states. It will be appreciated by a skilled person that when the diacetylene compounds of the present invention are in the non-coloured state, they are considered to be monomers. The first coloured state of the diacetylene compounds are formed on account of polymerisation of these monomers upon exposure to the applied transition stimulus. Polymerisation of at least a portion of the monomers enables the formation of the first coloured states of the diacetylene compounds. In addition, without being bound by theory, the inventors consider that the different first and second coloured states are achieved through changes in conjugation of the diacetylene polymer, i.e. a structural change, upon exposure to the deactivation temperature.

It will be understood be a skilled person that a coloured state of the deactivatable component is stable under ambient conditions.

The deactivatable component may be present in a composition according to the second aspect of the present invention in any suitable amount. Preferably, the composition comprises from 0.1 to 50 %, such as from 0.4 to 40 %, or even from 3 to 30 % of the deactivatable component based on the total solid weight of the composition. Most preferably, the composition comprises from 5 to 25 % of the deactivatable component based on the total solid weight of the composition.

The applied transition stimulus applied to the deactivatable component is radiation. It will be appreciated that the radiation selected will be the radiation required to facilitate a transition of the deactivatable component from the non- coloured to a coloured state. The radiation is selected from gamma radiation with a wavelength of less than 0.01 nm, X-ray radiation with a wavelength of from 0.01 to 10 nm, ultraviolet (UV) radiation with a wavelength of from 10 to 400 nm, and microwave radiation with a wavelength of from 1 mm to 1 m. Preferably, the applied transition stimulus is selected from ultraviolet (UV) with a wavelength of from 10 to 400 nm. More preferably, the applied transition stimulus is selected from ultraviolet (UV) with a wavelength of from 100 to 400 nm.

It will be appreciated that from the radiation and wavelength ranges detailed herein for the applied transition stimulus relating to the deactivatable component, a skilled person would select a specific applied transition stimulus as required to achieve the desired transition of the deactivatable component from a non- coloured to a coloured state. It will be appreciated that the specifically selected applied transition stimulus will differ depending upon the components in the composition.

The applied transition stimulus may be applied to the deactivatable component of the composition using any suitable means. Suitable means include laser excitation through application of radiation to the component or composition and thus the deactivatable component by a laser source(s). It will be understood by a skilled person that the applied transition stimulus may be applied to the component or composition at localised positions to selectively develop the coloured state of the deactivatable component at these localised positions. These localised positions may overlap with each other. Alternatively, it will be appreciated by a skilled person that the applied transition stimulus may be applied to the component or composition on or within a substrate by flood illumination, meaning that the composition as a whole is flooded with radiation. This can be done using any suitable lamp or bulb, such as a UV lamp, or medium pressure mercury or amalgam lamp or microwave powered UV lamp, a Xe, Hg or XeHg arc (broadband UV sources); a germicidal lamp, a diode bar; or LED(s). Where a broadband UV source is utilised, it will be appreciated that a range of wavelengths over the 10 to 400 nm range will be emitted. It will be understood by a skilled person that the radiation is applied to the composition for an appropriate amount of time required to facilitate the transition of the deactivatable component from the non-coloured state to the coloured state. Typically the time required to deliver sufficient radiation will depend upon the power of the means used to apply radiation and the method of application i.e. at localised positions, or by flood illumination. For example, in one embodiment, the applied transition stimulus may be applied to the deactivatable component for less than 120 seconds (such as between 30 to 110 seconds, or even between 75 to 105 seconds), or for less than 60 seconds, such as for less than 20 seconds, or even for less than 10 seconds. It will be appreciated that when applied using a laser source(s), the radiation dosage applied can be controlled by alteration of the time for which the radiation is applied, the power of the means used to apply the radiation (wattage) and thus, the fluence (amount of energy delivered per unit area) delivered by a laser source(s), i.e. J/cm ²

The deactivation temperature may be any suitable temperature. It will be appreciated that the temperature will be the temperature required to deactivate the non-coloured or coloured state of the deactivatable component. As discussed above, for the deactivation of coloured state, this may be accompanied by a transition from the coloured state to a further coloured state, i.e. from a first coloured state to a second deactivated coloured state. The deactivation temperature may be a temperature of from 50 to 160°C. Preferably, the deactivation temperature is from 55 to 140 °C.

The deactivation temperature may be applied to the deactivatable component either prior to the transition to the coloured state effected by the application of the applied transition stimulus, i.e. when the deactivatable component is in the non-coloured state, or after the transition to a coloured state effected by the application of the applied transition stimulus, i.e. when the deactivatable component is in a coloured state. After the application of the deactivation temperature, the deactivatable component is‘deactivated’ and will not undergo any subsequent transitions

As discussed above, when the deactivation temperature is applied to a first coloured state of a deactivatable component, the component may transition from the first coloured state to the second coloured state.

The deactivation temperature may be applied to the deactivatable component of the composition by any suitable means. Suitable means include laser excitation through application of radiation to the deactivatable component by a laser source(s). It will be understood by a skilled person that the deactivation temperature may be applied to the component or composition on or within the substrate at localised positions to selectively deactivate the non-coloured or the coloured state of the deactivatable component at these localised position. These localised positions may overlap with each other. Alternatively, it will be appreciated by a skilled person that the deactivation temperature may be applied to the deactivatable component by flood illumination, meaning that the composition as a whole is flooded with radiation. This may be done using a lamp or bulb, such as a IR lamp,; diode bar; or LED(s). It will further be appreciated that the deactivation temperature may be applied to the deactivatable component using a conductive temperature source. Conductive temperature sources include sources of steam and hot air, lamps, heat tunnels, LED(s), thermal print heads, hotplates, thermal conductors, hot liquids and heated substrates. It will be understood by a skilled person that the deactivation temperature is applied to the component or composition for an appropriate amount of time required to cause the deactivation of the non-coloured or coloured state of the deactivatable component. Typically the time required to deliver sufficient temperature will depend upon the power of the means used to apply radiation and the method of application i.e. at localised positions, by flood illumination, or using a conductive temperature source. For example, in one embodiment, the deactivation temperature may be applied to the deactivatable component for less than 120 seconds (such as between 30 to 110 seconds, or even between 75 to 105 seconds), or for less than 60 seconds, such as for less than 20 seconds, or even for less than 10 seconds.

It will be appreciated that when applied using a laser source(s), the radiation dosage applied to achieve the deactivation temperature can be controlled by alteration of the time for which the radiation is applied, the power of the means used to apply the radiation (wattage) and thus, the fluence (amount of energy delivered per unit area) delivered by a laser source(s), i.e. J/cm ²

It will be appreciated by a skilled person that the deactivation temperature may be applied to the deactivatable component using a combination of the suitable means listed above, i.e. using combinations of laser excitation at localised positions, flood illumination, and a conductive temperature source. For example, in one embodiment, the deactivation temperature may be applied to the deactivatable component using laser excitation at localised positions, in addition to using a conductive thermal energy source. In addition, it will be appreciated that where the deactivation temperature is applied using radiation, i.e. at localised positions using a laser source(s) or by flood illumination, the deactivatable component may be exposed to a temperature in excess of the stated temperature ranges for a very short period of time, i.e. microseconds. It will be understood that this will not have any significant effect on the result to be achieved.

The deactivation temperature may be applied to the deactivatable component using electromagnetic radiation selected from visible radiation with a wavelength of from 400 to 700 nm, and infrared (IR) with a wavelength of from 700 nm to 1 mm, including near-infrared (NIR) with a wavelength of from 700 to 1600 nm. Preferably, the deactivation temperature is applied using visible radiation with a wavelength of from 400 to 700 nm, infrared (IR) radiation with a wavelength of 10600 nm from a C0 ₂ laser, and near-infrared (NIR) radiation with a wavelength of from 700 to 1600 nm.

It will be appreciated that from the temperature and wavelength ranges detailed herein for the deactivation temperature, a skilled person would select a specific deactivation temperature as required to achieve the desired deactivation of the deactivatable component. It will be appreciated that the specifically selected deactivation temperature will differ depending upon the components in the composition.

A coloured state of the deactivatable component may have any colour. It will be appreciated by a skilled person that the means used to apply the applied transition stimulus or deactivation temperature (where there is a transition from a first coloured state to a second coloured state and accompanying colour change) will affect the colour of the coloured state formed. For example, where a laser source(s) is used to apply the applied transition stimulus or deactivation temperature, the fluence (amount of energy delivered per unit area) may affect the colour, lightness or intensity of the coloured state formed. In the context of the present invention, the fluence is dependent upon the power of the means used to apply the applied transition stimulus or deactivation temperature (wattage), and the time for which the applied transition stimulus or deactivation temperature is applied to a particular localised position on the substrate, which can be controlled by the scanning speed of the laser or the speed of the moving stage. These two variables can be altered to change the fluence. Where the fluence is low (e.g. lower power and/or shorter irradiation times), the coloured state of the deactivatable component will be of a less intense colour, and where the fluence is high (e.g. higher power and/or longer irradiation times), the coloured state of the deactivatable component will be of a more intense colour. In the context of the present invention, fluence values may range from 0.01 to 20 J/cm ² , such as from 0.1 to 10 J/cm ² and even from 0.5 to 5 J/cm ²

Preferably, a coloured state of the deactivatable component is selected from red, yellow or blue.

As detailed above, the deactivatable component may be present in a composition.

It will be appreciated by a skilled person that the composition according to the second aspect of the present invention may be formed through the combination of formulations containing different components of the composition, for example the deactivatable component may be in a separate formulation to an NIR absorber, the formulations being combined to form the composition according to the second aspect of the present invention.

The composition according to the second aspect of the present invention may further comprise one or more additional component capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an additional applied stimulus or additional temperature, wherein, if formed, the coloured states of the deactivatable component and the one or more additional component are different in colour. Preferably, the coloured state of the one or more additional component is selected from yellow, orange, black and red.

It will be appreciated that the one or more additional component and deactivatable component will be selected based on the colour(s) of their coloured states that can be achieved. Furthermore, the one or more additional component and the deactivatable component will be selected such that their formation of colour is triggered by different conditions. ‘Different conditions’ encompasses the differing orders of application of the applied transition stimulus, deactivation temperature and additional temperature or additional applied stimulus, as required, for the formation of colour for each of the one or more additional component and the deactivatable component.

The terms "non-coloured state", "coloured state", "stable coloured state" as defined above in relation to the deactivatable component are applicable to the one or more additional component. The term "transition" as defined above in relation to the deactivatable component is also applicable to the one or more additional component, the applied transition stimulus being replaced by the additional applied stimulus or additional temperature.

The one or more additional component may be selected to be any suitable component. Examples of suitable one or more additional components include, but are not limited to the following (a) to (e): (a) a pyrazole (thio)semicarbazone compound;

(b) a keto acid compound;

(c) a leuco dye;

(d) an oxyanion of a multivalent metal; and

(e) a compound formed from a salicylic aldehyde or salicylic ketone compound.

Groups (a) to (e) are as defined below:

(a) a pyrazole (thio)semicarbazone compound.

By the term "pyrazole (thio)semicarbazone compound" is meant a compound having a pyrazole group and a (thio) semicarbazone group. The brackets around thio indicate that the moeity may be present or absent. The term pyrazole group encompasses derivatives of a pyrazole group. Preferably, the pyrazole group is a pyrazolone, including the enol (C-OH) tautomer form. Preferably, the (thio) semicarbazone group is a semicarbazone.

Preferably, the pyrazole (thio)semicarbazone compound is a pyrazolone semicarbazone compound. Preferably, the pyrazole (thio)semicarbazone compound is a compound having the formula (III):

wherein each of A, B, C and D are independently selected from:

C1-18 alkyl; -CCI ₃ ; -CF ₃ ; C ₆ -12 aryl optionally substituted with Ci-i ₈ alkoxy, -CN, - CF ₃ , halogen, -N0 ₂ , or Ci-i ₈ alkyl; a heterocyclic ring and a heteroaryl.

Preferably, A is selected from C ₆ -12 aryl optionally substituted with Ci-i ₈ alkoxy, - CN, -CF ₃ , halogen, -N0 ₂ , or Ci-i ₈ alkyl, more preferably from C ₆ -s aryl, and most preferably phenyl.

Preferably, B is selected from Ci-i ₈ alkyl and C ₆ -12 aryl optionally substituted with Ci-i ₈ alkoxy, -CN, -CF ₃ , halogen, -N0 ₂ , or Ci-i ₈ alkyl, more preferably from Ci _-4 alkyl and C ₆ -s aryl, and most preferably from methyl and phenyl.

Preferably, C is selected from C ₆ -12 aryl optionally substituted with Ci-i ₈ alkoxy, - CN, -CF ₃ , halogen, -N0 ₂ , or Ci-i ₈ alkyl; -CCI ₃ ; and Ci-i ₈ alkyl; more preferably from C _6-8 aryl optionally substituted with Ci _-4 alkoxy, -CN, -CF ₃ or -N0 ₂ ; -CCI ₃ ; and Ci _-4 alkyl, and most preferably, from phenyl, 4-methoxy phenyl, 4- cyanophenyl, 4-(trifluoromethyl)phenyl, 4-nitrophenyl; -CCI ₃ ; and C(CH ₃ ) ₃ . Preferably, D is selected from C _6- 12 aryl optionally substituted with C _{M S} alkoxy, - CN, -CF ₃ , halogen, -N0 ₂ , or C _{M S} alkyl, more preferably from C ₆ -s aryl, and most preferably phenyl.

The pyrazole (thio)semicarbazone compound may be a component having the formula (IV):

wherein B is selected from C _{M S} alkyl and C _6- 12 aryl optionally substituted with Ci_ 18 alkoxy, -CN, -CF ₃ , halogen, -N0 ₂ , or Ci-i ₈ alkyl, preferably from Ci _-4 alkyl and C _6-8 aryl, and more preferably from methyl and phenyl, and C is selected from C _6- 12 aryl optionally substituted with C _{1 -18} alkoxy, -CN, -CF ₃ , halogen, -N0 ₂ , or C _{1 -18} alkyl; -CCI ₃ ; and C _1-18 alkyl; preferably from C ₆ -s aryl optionally substituted with Ci _-4 alkoxy, -CN, -CF ₃ or -N0 ₂ ; -CCI ₃ ; and Ci _-4 alkyl, and more preferably, from phenyl, 4-methoxy phenyl, 4-cyanophenyl, 4- (trifluoromethyl)phenyl, 4-nitrophenyl; -CCI ₃ ; and C(CH ₃ ) ₃ . Preferably, the pyrazole (thio)semicarbazone compound is selected from (£)- 2- ((5-hydroxy-1 ,3-diphenyl-1 /-/-pyrazol-4-yl)(phenyl)methylene)-A/- phenylhydrazine-1 -carboxamide (B and C are phenyl), (£)-2-((5-hydroxy-3- methyl-1 -phenyl-1 /-/-pyrazol-4-yl)(phenyl)methylene)-A/-phenylhydrazine-1 - carboxamide (B is methyl and C is phenyl), (£)-2-((5-hydroxy-1 ,3-diphenyl-1 /-/- pyrazol-4-yl)(4-nitrophenyl)methylene)-A/-phenylhydrazine-1 -carboxamide (B is phenyl and C is 4-nitrophenyl), (£)-2-((5-hydroxy-1 ,3-diphenyl-1 /-/-pyrazol-4- yl)(4-(trifluoromethyl)phenyl)methylene)-A/-phenylhydrazine- 1 -carboxamide (B is phenyl and C is 4-(trifluoromethyl)phenyl), (£)-2-((5-hydroxy-1 ,3-diphenyl-1 /-/- pyrazol-4-yl)(4-methoxyphenyl)methylene)-A/-phenylhydrazine- 1 -carboxamide (B is phenyl and C is 4-methoxyphenyl), (£)-2-((5-hydroxy-3-methyl-1 -phenyl-1 H- pyrazol-4-yl)(4-(trifluoromethyl)phenyl)methylene)-A/-phenyl hydrazine-1 - carboxamide (B is methyl and C is 4-(trifluoromethyl)phenyl), and (E)-2-((4- cyanophenyl)(3-hydroxy-2,5-diphenyl-2,3-dihydro-1 H-pyrazol-4-yl)methylene)-N- phenylhydrazine-1 -carboxamide (B is phenyl, and C is 4-cyanophenyl). More preferably, the pyrazole (thio)semicarbazone compound is selected from (£)- 2- ((5-hydroxy-1 ,3-diphenyl-1 /-/-pyrazol-4-yl)(phenyl)methylene)-A/- phenylhydrazine-1 -carboxamide (B and C are phenyl), and (£)-2-((5-hydroxy- 1 ,3-diphenyl-1 /-/-pyrazol-4-yl)(4-(trifluoromethyl)phenyl)methylene)-A/- phenylhydrazine-1 -carboxamide (B is phenyl and C is 4-(trifluoromethyl)phenyl), and (E)-2-((4-cyanophenyl)(3-hydroxy-2,5-diphenyl-2,3-dihydro-1 H-pyrazol-4- yl)methylene)-N-phenylhydrazine-1 -carboxamide (B is phenyl, and C is 4- cyanophenyl).

All references to the components of formulas (III) and (IV) are to be interpreted as covering the components of the formulas (III) and (IV) per se, and also, all tautomers or isomers thereof.

(b) a keto acid compound.

By the term "keto acid compound" is meant a compound having a carboxylic acid group and a ketone group.

Preferably, the keto acid compound is of formula (V):

wherein Xi _a , X _2a , and X _3a are independently selected from C, N, B and S; the two R groups may be the same or different, and are independently selected from: hydrogen; Ci-i ₈ alkyl; C ₆ -i ₂ aryl optionally substituted with Ci-i ₈ alkoxy, -CN, - CF ₃ , -N0 ₂ , halogen, or C _{M S} alkyl; halogen; -N0 _2; -CF ₃ ; -OR ³ ; -NR ³ ₂ ; -CN; -SR ³ ; - COR ³ ; -C0 ₂ R ³ ; and -CONR ³ ₂ ; wherein R ³ is selected from an alkali metal; hydrogen; Ci-i ₈ alkyl; and Ce-^ aryl optionally substituted with CM _S alkoxy, -CN, - CF ₃ , -N0 ₂ , halogen, or CM _S alkyl; or both R groups, together with the nitrogen atom to which they are attached, join together to form a cyclic amino group, wherein the cyclic amino group is optionally substituted with CM _S alkoxy, -CN, - CF ₃ , -N0 ₂ , halogen, or CM _S alkyl .

A may be the same as or different to B’ (defined below), and is independently selected from: hydrogen; Ci-i ₈ alkyl; C _6- 12 aryl optionally substituted with CM _S alkoxy, -CN, -CF ₃ , -N0 ₂ , halogen, or CM _S alkyl; a heterocyclic ring; a heteroaryl; halogen; -N0 ₂ ; -CF ₃ ; -OR ³ ; -NR ³ ₂ ; -CN; -SR ³ ; -COR ³ ; -C0 ₂ R ³ ; -CONR ³ ₂ ; wherein R ³ is selected from an alkali metal; hydrogen; Ci-i ₈ alkyl; and C _6- 12 aryl optionally substituted with CM _S alkoxy, -CN, -CF ₃ , -N0 ₂ , halogen, or CM _S alkyl; and

R ¹ is selected from

wherein Xi _b , X _2b , X3 _b and X _4b are independently selected from C, N, B and S; and B’ is the same or different to A and is independently selected from hydrogen; Ci-i ₈ alkyl; C _6- 12 aryl optionally substituted with CM _S alkoxy, -CN, -CF ₃ , -N0 ₂ , halogen, or CM _S alkyl; a heterocyclic ring; a heteroaryl; halogen; -N0 _2; -CF _3; - OR ³ ; -NR ³ ₂ ; -CN; -SR ³ ; -COR ³ ; -C0 ₂ R ³ ; -CONR ³ ₂ ; wherein R ³ is selected from an alkali metal; hydrogen; Ci-i ₈ alkyl; and Ce-^ aryl optionally substituted with Ci_ is alkoxy, -CN, -CF ₃ , -N0 ₂ , halogen, CM _S alkyl, hydroxyl (-OH), or -NR ₂ wherein R is as defined above. It will be appreciated that A and B’ may constitute a substituent at a single position on the benzene ring to which each of A and B’ relates or A and B’ may constitute multiple independently selected substituents at any of the available positions on the benzene ring to which each of A and B’ relates. For example, the benzene ring to which B’ relates may be substituted with a single substituent or up to 4 independently selected substituents.

Preferably, the keto acid compound is selected from formula (VI):

wherein Xi _a , X _2a , X3 _a , Xi _b , X2 _b , X3 _b and X _4b , R, A and B’ are as described above for formula (V).

Preferably, the keto acid compound is selected from formula (VII):

wherein R and B’ are as described above for formula (V). Preferably, the two R groups are the same and are selected from Ci-i ₈ alkyl; and C ₆ -i ₂ aryl optionally substituted with C _{M S} alkoxy, -CN, -CF ₃ , -N0 ₂ , halogen, or C _{M S} alkyl. More preferably, the two R groups are the same and C _{M S} alkyl, more preferably Ci _-6 alkyl. Preferably, B’ is independently selected from hydrogen; -N0 ₂ and halogen, more preferably, hydrogen and chlorine, and most preferably hydrogen. Preferably, the keto acid compound is selected from2-(4-(dimethylamino)-2- hydroxybenzoyl)benzoic acid, 2-(4-(dibutylamino)-2-hydroxybenzoyl)benzoic acid, 2-(4-(diethylamino)-2-hydroxybenzoyl)benzoic acid, and 2, 3,4,5- tetrachloro-6-(4-(diethylamino)-2-hydroxybenzoyl)benzoic acid. More preferably, 2-(4-(dimethylamino)-2-hydroxybenzoyl)benzoic acid, 2-(4-(dibutylamino)-2- hydroxybenzoyl)benzoic acid, and 2-(4-(diethylamino)-2-hydroxybenzoyl)benzoic acid.

The keto acid compounds of formulas (V) to (VII) are commercially available, for example, they can be sourced from Chameleon Speciality Chemicals Limited. It is noted that in one embodiment, the keto acid compound may be in the form of a‘dimer’, whereby B’ denotes a -C0 ₂ R ³ group (where R ³ is hydrogen such that the benzene ring carries two carboxyl groups) and also, an independently selected -COR ³ group, where R ³ is a C _6- 12 aryl substituted with hydroxyl (-OH) and NR ₂ , wherein R is as defined above for formula (V). Preferably, the -C0 ₂ R ³ group (where R ³ is hydrogen such that the benzene ring carries two carboxyl groups) is at X _2b and the -COR ³ group is at X _3b .

(c) a leuco dye.

Leuco dyes are well known to a skilled person as compounds capable of forming colour. They can be photochromic (change colour on exposure to light such as UV light), chemochromic, thermochromic or halochromic (change colour on exposure to change in environmental pH). Examples of suitable leuco dyes are contained in WO2015/015200 and WO2013/068729, the content of which is incorporated by reference. Suitable lecuo dyes include, but are not limited to any commercially available or chemically synthesisable leuco dye, including but not limited to: commercially available photochromic, thermochromic, chemochromic, and halochromic leuco dyes. Examples of suitable leuco dyes include, but are not limited to: spiroxazines, naphthopyrans, phthalides, fluorans, triarylmethanes, benzoxazines, quinazolines, spiropyrans, quinones, tetrazolium salts, thiazines, phenazines and oxazines. Suitable suppliers of leuco dyes include, but are not limited to: Yamada Chemical Company Limited, Chameleon Speciality Chemicals Limited, and Connect Chemicals.

The leuco dye may be selected from: 2-Anilino-3-diethylamino-6-methylfluoran (Chameleon Black 1 ), 2-Anilino-6-dibutylamino-3-methylfluoran (Chameleon Black 2), 6-(Dimethylamino)-3,3-bis [4-(dimethylamino) phenyl] phthalide (Chameleon Blue 3), 4,4'-[(9-butyl-9H-carbazol-3-yl)methylene]bis[N-methyl-N- phenylaniline] (Chameleon Blue 4), 3,3'-Bis(1 -n-octyl-2-methylindol-3- yl)phthalide (Chameleon Red 5), 6'-(Diethylamino)-3-oxo-spiro [isobenzofuran- 1 (3H),9'-[9H] xanthene]-2'-carboxylic acid ethyl ester (Chameleon Orange 6), 7- [4-(diethylamino)-2-ethoxyphenyl]-7-(2-methyl-1 -octyl-1 H-indol-3-yl) Furo[3,4- b]pyridin-5(7H)-one (Chameleon Blue 8),

2'-(Dibenzylamino)-6'- (diethylamino)fluoran (Chameleon Blue 9), N,N-dimethyl-4-[2-[2-(octyloxy)phenyl]-6-phenyl-4-pyridinyl] - Benzenamine (Chameleon Yellow 10), and 6'-(diethylamino)-2'-[(dimethylphenyl) amino]-3'- methylspiro [isobenzofuran-1 (3H),9'-[9H]xanthene]-3-one (chameleon Black 15).

Preferably, the leuco dye is -(dimethylamino)-3,3-bis [4-(dimethylamino) phenyl] phthalide (Chameleon Blue 3), 7-[4-(diethylamino)-2-ethoxyphenyl]-7-(2-methyl- 1 -octyl-1 H-indol-3-yl) furo[3,4-b]pyridin-5(7H)-one (Chameleon Blue 8), 3,3'- bis(1 -n-octyl-2-methylindol-3-yl)phthalide (Chameleon Red 5), 2-anilino-3- diethylamino-6-methylfluoran (Chameleon Black 1 , ODB-1 ), 2-anilino-6- dibutylamino-3-methylfluoran, (Chameleon Black 2, ODB-2), N,N-dimethyl-4-[2- [2-(octyloxy)phenyl]-6-phenyl-4-pyridinyl]- benzenamine (Chameleon Yellow 10), 6'-(diethylamino)-2'-[(dimethylphenyl) amino]-3'-methylspiro [isobenzofuran- 1 (3H),9'-[9H]xanthene]-3-one (Chameleon Black 15); all commercially available from Chameleon Speciality Chemicals Limited.

(d) an oxyanion of a multivalent metal.

The use of oxyanions of multivalent metals in laser-markable compositions are disclosed in US7485403, the content of which is incorporated herein by reference. A particularly preferred oxyanion is ammonium octamolybdate (NH ₄ ) ₄ MO ₈ 0 ₂₆ or“AOM”, which is a commercially available molybdenum composition with the CAS number 12411-64-2. The AOM pigment will typically be formulated together with a binder, e.g. a polymeric binder, in the compositions of the invention. Suitable oxyanions include molybdate, tungstate or analogous transition metal compounds, including di- and hept-molybdates. Preferably, the oxyanion of a multivalent metal is ammonium octamolybdate (AOM).

(e) a compound formed from a salicylic aldehyde or salicylic ketone compound.

By the term "a compound formed from a salicylic aldehyde or salicylic ketone compound" is meant a compound formed from a parent salicylic aldehyde or salicylic ketone compound (aldehyde or ketone derivatives of salicylic acid).

Preferably, the compound formed from a salicylic aldehyde or salicylic ketone compound is a compound formed from the condensation reaction of a linked primary diamine and independently selected from two salicylic aldehyde or salicylic ketone compounds. By the term "linked primary diamine" is meant a compound comprising two primary amine groups joined by a carbon chain of 0 to 20 carbon atoms, preferably 0 to 10 carbon atoms, more preferably 0 to 8 carbon atoms, and most preferably 0 to 6 carbon atoms.

Preferably, the compound formed from a salicylic aldehyde or salicylic ketone compound is a compound formed from the condensation reaction of hydrazine and independently selected from two salicylic aldehyde or salicylic ketone compounds.

The compound formed from a salicylic aldehyde or salicylic ketone compound may have the following formula (VIII):

wherein R ¹ and R ² may be the same or different and are independently selected from hydrogen; halogen; hydroxyl; C _{M S} alkoxy; C _{M S} alkyl; C _{M S} cycloalkyl; a primary, secondary or tertiary amino group; -CN; -N0 ₂ ; -CF ₃ ; -COOH; -COR ³ ; - CONR ³ ₂ ; a heterocyclic ring; a heteroaryl and Ce-^aryl optionally substituted with C1-18 alkoxy, -CN, -CF ₃ , -N0 ₂ , halogen, or C _{M S} alkyl;

R ³ and R ⁴ may be the same or different and are independently selected from hydrogen, Ci-i ₈ alkyl, Ce-^aryl, and Ci-i ₈ alkyl-C ₆ -i2aryl; and

Xia, X _2a , X _3a , X _4a , Xi _b , X _2b , Xs _b and X _4b are independently selected from C, N or S.

It will be appreciated that R ¹ and R ² may constitute a substituent at a single position on the benzene ring to which each of R ¹ and R ² relates or R ¹ and R ² may constitute multiple independently selected substituents at any of the available positions on the benzene ring to which each of R ¹ and R ² relates. For example, R ¹ or R ² may constitute a single substituent on the benzene ring to which it relates, or R ¹ or R ² may constitute two substituents on the benzene ring to which it relates, the two substituents being different and situated at different positions on the benzene ring. For example, R ¹ or R ² may constitute a single substituent on the benzene ring to which it relates, or R ¹ or R ² may constitute two substituents on the benzene ring to which it relates, the two substituents being different and situated at different available positions on the benzene ring. Preferably, R ¹ and R ² are the same and are selected from hydrogen; halogen; hydroxyl; C _{M S} alkoxy including methoxy; C _{M S} alkyl including methyl, tertiary butyl and isopropyl; a secondary amino group (including -NR ₂ wherein R is Ci _-6 alkyl such as diethylamino and dimethylamino); -CN, -N0 ₂ , -CF ₃ , -COOH; C _6- i ₂ aryl optionally substituted with C _{M S} alkoxy, -CN, -CF ₃ , -N0 ₂ , halogen, or C _{M S} alkyl, including phenyl; and a heterocyclic ring such as pyridyl. More preferably, R ¹ and R ² are the same and are selected from hydrogen; halogen; hydroxyl; Ci_ i ₈ alkoxy including methoxy; a secondary amino group (including -NR ₂ wherein R is Ci-e alkyl such as diethylamino and dimethylamino); and N0 ₂ . Preferably, R ³ and R ⁴ are the same and are selected from hydrogen and Ci_ i ₂ alkyl. More preferably, R ³ and R ⁴ are the same and are selected from hydrogen and Ci _-6 alkyl. Most preferably, R ³ and R ⁴ are the same and are hydrogen.

Preferably, Xi _a , X _2a , X3 _a , X _4a , Xi _b , X2 _b , X3 _b and X _4b are independently selected from C or N. More preferably, Xi _a , X _2a , X3 _a , X _4a , Xi _b , X2 _b , X3 _b and X _4b are C.

Or, the compound formed from a salicylic aldehyde or salicylic ketone compound has the following formula (IX):

wherein R ¹ , R ² , R ³ , R ⁴ and Xi _a , X _2a , X _3a , X _4a , Xi _b , X _2b , X _3b and X _4b are as defined above for formula (VIII). Preferably, the compound formed from a salicylic aldehyde or salicylic ketone compound is 2,2'-((1 E,TE)-hydrazine-1 ,2- diylidenebis(methaneylylidene))diphenol, 6,6'-((1 E, 1 '£)-hydrazine-1 ,2- diylidenebis(methaneylylidene))bis(3-nitrophenol), 3,3’-((1 E,1’E)-hydrazine-1 ,2- diylidenebis(methaneylylidene))bis(benzene-1 ,2-diol), 6,6’-((1 E,1’E)-hydrazine- 1 ,2-diylidenebis(methaneylylidene))bis(4-bromo-2-methoxypheno l), 6,6’-

((1 E, 1’E)-hydrazine-1 ,2-diylidenebis(methaneylylidene))bis(3- (diethylamino)phenol), 2,2’-((1 E, 1’E)-hydrazine-1 ,2-diylidenebis(ethan-1 -yl-1 - ylidene))diphenol and 1 ,1’-((1 E, 1’E)-hydrazine-1 ,2- diylidenebis(methaneylylidene))bis(naphthalene-2-ol). Most preferably, the compound of formula formed from a salicylic aldehyde or salicylic ketone compound is 6,6’-((1 E, 1’E)-hydrazine-1 ,2-diylidenebis(methaneylylidene))bis(3- nitrophenol).

It will be appreciated by a skilled person that the selection of the additional applied stimulus or additional temperature is dependent upon the nature of the one or more additional component.

When the one or more additional component is a compound of formula (III) or (IV), a compound of formula (V), (VI) or (VII), a leuco dye or a compound of formula (VIII) or (IX), the additional applied stimulus may be utilised to facilitate a transition from the non-coloured state to a coloured state of the one or more additional component. Further, when the one or more additional component is a compound of formula (III) or (IV), a compound of formula (V), (VI) or (VII), a lecuo dye, an oxyanion of a multivalent metal or a compound of formula (VIII) or (IX), the additional temperature may be utilised to facilitate a transition from the non-coloured state to a coloured state of the one or more additional component.

When the one or more additional component is a compound of formula (III) or (IV), the one or more additional component may be accompanied in the composition by an acid or base-generating agent. It will be appreciated by a skilled person that the acid or base-generating agent and the one or more additional component of formula (III) or (IV) interact to achieve colour formation. The acid- or base-generating agent is present to facilitate a pH change through generation of acid or base (for the acid-generating or base-generating agents respectively) upon application of the additional applied stimulus or additional temperature to the composition and thus the compound of formula (III) or (IV) and acid or base-generating agent. This acid or base generation facilitates the transition of the one or more additional component of formula (III) or (IV) to transition from a non-coloured state to a coloured state. By‘acid’ is meant any molecular entity or chemical species capable of donating a hydrogen (proton) or capable of forming a covalent bond with an electron pair. By‘base’ is meant a chemical species or molecular entity having an available pair of electrons capable of forming a covalent bond with a proton, or with a vacant orbital of some other species.

Suitable acid-generating agents include any suitable commercially available or chemically synthesisable acid-generating agents. Suitable acid-generating agents include, but are not limited to the following: thermal acid-generating agents (TAGs) based on amine salts of borobenzilate and tri-n-butylammonium borodisalicylate; photoacid-generating agents such as but not limited to triphenylsulfonium triflate, triphenylsulfonium hexafluorophosphate, triphenylsulfonium perluorobutane sulfonate, triphenylsulfonium trifluoromethylsulfonate, N-phenylbis(trifluoromethanesulfonimide), Bisphenol derivatives including but not limited to bisphenol A, bisphenol F, bisphenol S, bisphenol E, bisphenol B, bisphenol AF, bisphenol AP, and bisphenol BP. Suitable photoacid-generating agents include those described in US 8932797, the content of which is incorporated herein by reference.

Suitable base-generating agents include any suitable commercially available or chemically synthesisable base-generating agents. Suitable base-generating agents include, but are not limited to the following: thermal base-generating agents such as n-phenyliminodiacetic acid, 1 ,2-bis(2-aminophenoxy)-ethane- N,N,N’,N’-tetraacetic acid, and N-methylpyridinium oxalate; and photobasic- generating agents such as 9-anthrylmethyl 4’-nitrophenylcarbonate, 9- anthrylmethyl 1 -piperidinecarboxylate, and 2-anthraquinonylmethyl 4’nitrophenylcarbonate. Suitable thermal base-generating agents include those described in WO2015199219 and photobase-generating agents include those described in EP2368875, the content of each of which is incorporated herein by reference.

It will be understood by a skilled person that the selection of the acid- or base- generating agent is dependent upon the particular compound of formula (III) or (I IV) utilised in the composition. The requirement of either an acid- or a base- generating agent can be determined by a skilled person.

It will further be appreciated by a skilled person that the selection of the additional applied stimulus or additional temperature is dependent upon the nature of the acid- or base-generating agent accompanying the compound of formula (III) or (IV). It will be appreciated by a skilled person that the additional applied stimulus is utilised to facilitate a transition when a photoacid- or photobase-generating agent is present in relation to the compound of formula (INI) or (IV), and the additional temperature is utilised to facilitate a transition when a thermal acid- or base-generating agent is present in relation to the compound of formula (III) or (IV).

When the one or more additional component is a compound of formula (V), (VI) or (VII) or a leuco dye, the one or more additional component is accompanied in the composition by an acid-generating agent, the acid-generating agent being as described above. The additional applied stimulus or additional temperature is applied to the composition as described above to facilitate a transition from the non-coloured to the coloured state of the one or more additional component. It will be appreciated by a skilled person that the acid-generating agent and the one or more additional component of formula (V), (VI) or (VII) or a leuco dye interact to achieve colour formation. The acid-generating agent is present to facilitate a pH change through generation of acid upon application of the additional applied stimulus or additional temperature to the composition and thus the one or more additional component and acid -generating agent. This acid generation facilitates the transition of the one or more additional component of formula (V), (VI) or (VII) or the leuco dye from a non-coloured state to a coloured state. It will be understood by a skilled person that the selection of the acid-generating agent is dependent upon the particular compound of formula (V), (VI) or (VII), or leuco dye utilised in the composition. It will further be appreciated by the skilled person that the selection of the additional applied stimulus or additional temperature is dependent upon the nature of the acid-generating agent accompanying the compound of formula (V), (VI) or (VII), or the leuco dye. It will be appreciated by a skilled person that the additional applied stimulus is utilised to facilitate a transition when a photoacid-generating agent is present in relation to the compound of formula (V), (VI) or (VII), or lecuo dye, and the additional temperature is utilised to facilitate a transition when a thermal acid-generating agent is present in relation to the compound of formula (V), (VI) or (VII), or a leuco dye.

When the one or more additional component is a compound of formula (VIII) or (IX), the one or more additional component is preferably accompanied in the composition by an acid- or base-generating agent, the acid- or base-generating agent being as described above. The additional applied stimulus or additional temperature is applied to the composition as described above to facilitate a transition from the non-coloured to the coloured state of the compound of formula (VIII) or (IX). It will be appreciated by a skilled person that the acid or base-generating agent and the one or more additional component of formula (VIII) or (IX) interact to achieve colour formation. The acid- or base-generating agent is present to facilitate a pH change through generation of acid or base upon application of the additional applied stimulus or additional temperature to the composition and thus the one or more additional component and acid- or base-generating agent. This acid or base generation facilitates the transition of the one or more additional component of formula (VIII) or (IX) to transition from a non-coloured state to a coloured state.

It will be understood by a skilled person that the selection of the acid- or base- generating agent is dependent upon the particular compound of formula (VIII) or (IX) utilised in the composition. The requirement of either an acid- or a base- generating agent can be determined by a skilled person. It will further be appreciated by a skilled person that the selection of the additional applied stimulus or additional temperature is dependent upon the nature of the acid- or base-generating agent accompanying the compound of formula (VIII) or (IX). It will be appreciated by a skilled person that the additional applied stimulus is utilised to facilitate a transition when a photoacid- or photobase-generating agent is present in relation to the compound of formula (VIII) or (IX), and the additional temperature is utilised to facilitate a transition when a thermal acid- or base-generating agent is present in relation to the compound of formula (VIII) or (IX).

The additional applied stimulus is radiation. It will be appreciated that the radiation will be the radiation required to facilitate a transition of the one or more additional compound from the non-coloured to a coloured state. The radiation selected will therefore be dependent upon the one or more additional component present in the composition. The radiation is selected from gamma radiation with a wavelength of less than 0.01 nm, X-ray radiation with a wavelength of from 0.01 to 10 nm, and microwave radiation with a wavelength of from 1 mm to 1 m. Preferably, the additional applied stimulus is selected ultraviolet (UV) radiation with a wavelength of from 10 to 400 nm. More preferably, the additional applied stimulus is selected from ultraviolet (UV) radiation with a wavelength of from 100 to 400 nm.

It will be appreciated that from the radiation and wavelength ranges detailed herein for the one or more additional component, a skilled person would select a specific additional applied stimulus as required to achieve the desired transition of the one or more additional component from a non-coloured to a coloured state. It will be appreciated that the specifically selected additional applied stimuli will differ depending upon the components in the composition.

The additional applied stimulus may be applied to the one or more additional component of the composition by any suitable means. Suitable means include laser excitation through application of radiation to the composition and thus the fourth component by a laser source(s). It will be understood by a skilled person that the additional applied stimulus may be applied to the composition at localised positions to selectively develop the coloured state of the one or more additional component at these localised positions in the composition. These localised positions may overlap with each other. Alternatively, it will be appreciated by a skilled person that the additional applied stimulus may be applied to the composition on or within the substrate by flood illumination, meaning that the composition as a whole is flooded with radiation. This can be done using any suitable lamp or bulb, such as a UV lamp, or medium pressure mercury or amalgam lamp or microwave powered UV lamp, a Xe, Hg or XeHg arc (broadband UV sources); a germicidal lamp, a diode bar; or LED(s). When a broadband UV source is utilised, it will be appreciated by a skilled person that a range of wavelengths will be emitted over the 10 to 400 nm range. It will also be understood by a skilled person that the radiation is applied to the composition for an appropriate amount of time required to facilitate the transition of the one or more additional component from the non-coloured state to the coloured state. Typically the time required to deliver sufficient radiation will depend upon the power of the means used to apply radiation and the method of application i.e. at localised positions, or by flood illumination. For example, in one embodiment, the additional applied stimulus may be applied to the one or more additional component for less than 120 seconds (such as between 30 to 110 seconds, or even between 75 to 105 seconds), or for less than 60 seconds, such as for less than 20 seconds, or even for less than 10 seconds.

It will be appreciated that when applied using a laser source(s), the additional applied stimulus can be controlled by alteration of the time for which the radiation is applied, the power of the means used to apply the radiation (wattage) and thus, the fluence (amount of energy delivered per unit area) delivered by a laser source(s), i.e. J/cm ²

The additional temperature may be any suitable temperature. It will be appreciated by a skilled person that the additional temperature will be a temperature required to facilitate a transition of the one or more additional component from the non-coloured to a coloured state. The additional temperature will therefore be selected dependent upon the one or more additional component present in the composition. The additional temperature may be a temperature of from 50 to 300 °C. Preferably, the additional temperature is from 50 to 250 °C, such as from 80 to 200 °C.

The additional temperature may be applied to the one or more additional component of the composition by any suitable means. Suitable means include laser excitation through application of radiation to the composition and thus the one or more additional component by a laser source(s). It will be understood by a skilled person that the additional temperature may be applied to the composition at localised positions to selectively develop the coloured state of the one or more additional component at these localised positions in the composition. These localised positions may overlap with each other. Alternatively, it will be appreciated by a skilled person that the additional temperature may be applied to the one or more additional component by flood illumination, meaning that the composition as a whole is flooded with radiation. This may be done using a lamp or bulb, such as a IR lamp; diode bar; or LED(s). It will further be appreciated that the additional temperature may be applied to the one or more additional component using a conductive temperature source. Conductive temperature sources include sources of steam and hot air, lamps, heat tunnels, hotplates, LED(s), thermal print heads, thermal conductors, hot liquids and heated substrates. It will be understood by a skilled person that the additional temperature is applied to the composition for an appropriate amount of time required to facilitate the transition of the one or more additional component from the non-coloured to the coloured state. Typically the time required to deliver sufficient temperature will depend upon the power of the means used to apply radiation and the method of application i.e. at localised positions, by flood illumination, or using a conductive temperature source. For example, in one embodiment, the additional temperature may be applied to the one or more additional component for less than 120 seconds (such as between 30 to 110 seconds, or even between 75 to 105 seconds), or for less than 60 seconds, such as for less than 20 seconds, or even for less than 10 seconds.

It will be appreciated that when applied using a laser source(s), the additional temperature can be controlled by alteration of the time for which the radiation is applied, the power of the means used to apply the radiation (wattage) and thus, the fluence (amount of energy delivered per unit area) delivered by a laser source(s), i.e. J/cm ²

It will be appreciated by a skilled person that the additional temperature may be applied to the one or more additional component using a combination of the suitable means listed above, i.e. using combinations of laser excitation at localised positions, flood illumination, and a conductive temperature source. For example, in one embodiment, the additional temperature may be applied to the one or more additional component using laser excitation at localised positions, in addition to using a conductive thermal energy source.

In addition, it will be appreciated that where the additional temperature is applied using radiation, i.e. at localised positions using a laser source(s) or by flood illumination, the composition and thus the one or more additional component may be exposed to a temperature in excess of the stated temperature ranges for a very short period of time, i.e. microseconds. It will be understood that this will not have any significant effect on the result to be achieved.

The additional temperature may be applied to the one or more additional component using radiation selected from visible radiation with a wavelength of from 400 to 700 nm, and infrared (IR) radiation with a wavelength of from 700 nm to 1 mm, including near-infrared (NIR) radiation with a wavelength of from 700 to 1600 nm. Preferably, the additional temperature is applied using infrared (IR) radiation with a wavelength of from 700 nm to 1 mm, infrared radiation with a wavelength of 10600 nm using a C0 ₂ laser, near-infrared (NIR) radiation with a wavelength of 700 to 1600 nm, and visible radiation with a wavelength of from 400 to 700 nm.

It will be appreciated that from the temperature and wavelength ranges detailed herein for the one or more additional component, a skilled person would select a specific additional temperature as required to achieve the desired transition of the one or more additional component. It will be appreciated that the specifically selected additional temperature will differ depending upon the components in the composition. The coloured state of the one or more additional component may have any colour. It will be appreciated by a skilled person that the means used to apply the additional applied stimulus or additional temperature will affect the colour of the coloured state formed. For example, where a laser source(s) is used to apply the additional applied stimulus or additional temperature, the fluence (amount of energy delivered per unit area) may affect the colour, intensity or lightness of the coloured state of the one or more additional component formed. In the context of the present invention, the fluence is dependent upon the power of the means used to apply the additional applied stimulus or additional temperature (wattage), and the time for which the additional applied stimulus or additional temperature is applied to a particular localised position on the substrate, which can be controlled by the scanning speed of the laser or the speed of the moving stage. These two variables can be altered to change the fluence. Where the fluence is low (e.g. lower power and/or shorter irradiation times), the coloured state of the one or more additional component will be of a less intense colour, and where the fluence is high (e.g. higher power and/or longer irradiation times), the coloured state of the one or more additional component will be of a more intense colour. Changing the fluence may also result in the coloured state of the one or more additional component changing colour. For example, low fluence may form a coloured state of the one or more additional component having a yellow colour, and higher fluence may form the same coloured state but having an orange or red colour. This is particularly applicable for (a), (b) and (e). In the context of the present invention, fluence values may range from 0.01 to 20 J/cm ² , such as from 0.1 to 10 J/cm ² and even from 0.5 to 5 J/cm ² .

Further, it will be appreciated by a skilled person that the required fluence from the additional applied stimulus or additional temperature to facilitate a transition from the non-coloured state to a coloured state of the one or more additional component may be different to the required fluence from the applied transition stimulus or deactivation temperature. Preferably, the required fluence from the additional applied stimulus or additional temperature will be different to the require fluence from the applied transition stimulus or deactivation temperature. It will be understood by a skilled person that if an acid- or base-generating agent accompanies the one or more additional component in the composition according to the second aspect of the present invention, the acid- or base- generating agent is exclusive to the one or more additional component and will not affect the deactivatable component.

It will be appreciated by a skilled person that the composition according to the second aspect of the present invention may comprise more than one of the one or more additional components.

It will be appreciated by a skilled person that if more than one of the one or more additional components are present in the composition, two of the one or more additional components cannot be selected to both by accompanied by an acid- or base-generating agent, i.e. the composition may only comprise one acid- or base-generating agent. If two of the one or more additional components are present, they will be selected such that only one requires an acid- or base- generating agent, or in certain instances, the acid- or base-generating agent associated with one of the two components will also interact with the other of the two components as discussed above.

Preferably, if the one or more additional component is present, the composition comprises a deactivatable component and a leuco dye. Preferably, if the one or more additional component is present, the composition comprises a deactivatable component, a leuco dye, and an oxyanion of a multivalent metal.

Preferably, if the one or more additional component is present, the composition comprises a deactivatable component, a pyrazole (thio)semicarbazone compound, and an oxyanion of a multivalent metal.

Preferably, if the one or more additional component is present, the composition comprises a deactivatable component and a keto acid compound. Preferably, if the one or more additional component is present, the composition comprises a deactivatable component and a compound formed from a salicylic ketone or salicylic aldehyde compound.

It will be understood by a skilled person that a coloured state of the one or more additional component is stable under ambient conditions.

It will be appreciated that a composition comprising the deactivatable component and one or more additional component enables the production of a broad range of colours in the formation of an image. The different applied transition stimulus and/or deactivation temperature, and additional applied stimulus or additional temperature can be applied in different combinations as required across the whole composition or at particular localised positions, enabling the formation many different colours. It will be appreciated that the stimuli and temperatures used are dependent upon the components present in the composition. The invention thus enables the formation of desired single- and multi-coloured images with a broad colour gamut.

If present, the one or more additional component may be present in the composition in any suitable amount. Preferably, the composition comprises from 0.1 to 50%, such as from 0.1 to 40 %, or even from 3 to 30 % of the one or more additional component based on the total solid weight of the composition. Most preferably, the composition comprises from 5 to 25 % of the one or more additional component based on the total solid weight of the composition.

If required, the acid or base-generating agent relating to the one or more additional component may be individually present in the composition in any suitable amount. Preferably, the composition comprises from 1 to 50 %, such as from 5 to 40 % of the acid or base-generating agent based on the total solid weight of the composition. Most preferably, the composition comprises from 5 to 30 % of the acid or base-generating agent based on the total solid weight of the composition.

If acid- or base-generating agent is required, the ratio of the acid-or base generating to the one or more additional component based on the total solid weight of the composition is from 4: 1 to 1 :4, preferably from 3: 1 to 1 :3, and more preferably from 2:1 to 1 :2.

The composition according to the second aspect of the present invention may further comprise a binder. Suitable binders will be well known to a person skilled in the art. Examples of suitable binders include, but are not limited to the following: polymeric binders such as acrylic polymers, styrene polymers and hydrogenated products thereof; vinyl polymers; polyolefins and hydrogenated or epoxidised products thereof; aldehyde-containing polymers; epoxide-containing polymers; polyamides; polyesters; polyurethanes; sulphone-containing polymers; natural products and derivatives thereof; and combinations thereof. The binder may be present in the composition in any suitable amount. Preferably, the composition comprises from 1 to 50 %, such as from 5 to 40 % and most preferably, from 10 to 35 % of binder based on the total solid weight of the composition.

The composition according to the second aspect of the present invention may further comprise a near-infrared radiation (NIR) absorber. It will be appreciated that an NIR absorber may be utilised when NIR radiation is to be utilised, the NIR absorber being capable of enhancing the absorption of the NIR radiation. Examples of suitable NIR absorbers include, but are not limited to the following: inorganic copper salts such as copper (II) hydroxyl phosphate; organic NIR dyes and pigments such as N,N,N’,N’-tetrakis(4-dibutylaminophenyl)-p-benzoquinone bis(iminium hexafluoro-antimonate); non-stoichiometric inorganic compounds such as reduced indium tin oxide, reduced zinc oxide, reduced tungsten oxide (tungsten bronze), reduced doped tungsten oxide, reduced antimony tin oxide, or doped metal oxides such as aluminium-doped zinc oxide (AZO) and fluorine- doped tin oxide (FTO); conductive polymers such as poly polystyrene sulfonate (PEDOT); and combinations thereof. Preferably, the NIR absorber is a non- stoichiometric inorganic compound. Preferably, the composition comprises from 0.05 to 5 %, such as from 0.05 to 4 % and most preferably, from 0.05 to 3 % of an NIR absorber based on the total solid weight of the composition.

The composition according to the second aspect of the present invention may further comprise a curable compound. Suitable curable compounds will be well known to a person skilled in the art. Examples of suitable curable compounds include, but are not limited to: any commercially available monomers, oligomers, monomer and oligomer mixtures, or photoinitiators. The curable compound may be present in the composition in any suitable amount.

The composition according to the second aspect of the present invention may further contain an additive or combination of additives. Suitable additives will be well known to a person skilled in the art. Examples of suitable additives include, but are not limited to the following: polymers; light or energy absorbing agents; UV absorbers; surfactants; wetting agents; drying promoters; colourants such as pigments; tinting agents; fluorescent agents; plasticisers; optical brighteners; oxidising or reducing agents; stabilisers; light stabilising agents such as hindered amines; rheology modifiers such as thickening or thinning agents; humectants; adhesion promotors; acid or base scavenging agents; retarders; defoamers; antifoaming agents; and combinations thereof. Preferably, the composition comprises 0.1 to 7 %, such as from 0.1 to 5 %, or even from 0.1 to 3 % of additives based on the total solid weight of the composition.

The composition according to the second aspect of the present invention may further comprise a solvent. The composition may comprise a single solvent or a mixture of solvents. The solvent may comprise water, an organic solvent, a mixture of water and an organic solvent, or a mixture of organic solvents. Suitable organic solvent include, but are not limited to the following: alcohols such as ethanol, n-propanol, isopropanol and n-butanol; esters such as ethyl acetate, butyl acetate, and n-hexyl acetate; aromatic hydrocarbons such as benzene, toluene, xylene, and solvent naphtha 100, 150, 200; ketones such as acetone, cyclohexanone, methylisobutyl ketone, and methyl ethyl ketone; glycols such as butyl glycol; glycol ethers such as methoxy propanol, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether; and combinations thereof. Preferably, the solvent is present in the composition in amounts of from 15 to 70 %, such as from 15 to 60 %, or even from 20 to 55 %.

The composition according to the second aspect of the present invention preferably comprises, in addition to the deactivatable component and optional one or more additional component and acid- or base-generating agents, a binder, an additive or combination of additives, and a solvent or combination of solvents. If near-infrared radiation is to be used as the deactivation temperature or additional temperature, an NIR absorber is preferably present.

The composition according to the second aspect of the present invention may have a viscosity of from 14 to 120 Zahn seconds (efflux time), suitably measured using a Zahn cup #2 viscosity measurement device at a temperature of 16 to 30 °C. It will be appreciated that the viscosity of the composition is dependent upon a number of factors, including the number, type and amount of the components present in the composition in addition to the printing application and desired coat weight of the composition when applied on a substrate.

It will be appreciated by a skilled person that the composition according to the second aspect of the present invention may be formed through the combination of formulations containing different components of the composition, for example the deactivatable component may be in a separate formulation to an NIR absorber, the formulations being combined to form the composition according to the second aspect of the present invention.

It will further be appreciated that if a one or more additional component is present in the composition according to the first aspect of the present invention, the composition may be formed through the combination of formulations containing the different components of the composition, for example the deactivatable component and the one or more additional component may each be in separate formulations, the formulations being combined together to form the composition according to the second aspect of the present invention. It will be further appreciated that the formulations comprise components such as binders, solvents and additives.

The composition according to the second aspect of the present invention may be applied to or incorporated within any suitable substrate. It will be appreciated by a skilled person that the components of a composition will likely vary depending on the substrate to which the composition is to be applied or incorporated within. Thus, according to a third aspect of the present invention there is provided a substrate comprising the composition according to the second aspect of the present invention applied to or incorporated within.

Examples of suitable substrates to which the composition may be applied, include, but are not limited to: polymers and recycled polymer materials such as polyethylene terephthalate (PET), polyethylene (PE), low density polyethylene (LDPE), high density polyethylene (HDPE), polystyrene (PS), polypropylene (PP), orientated polypropylene (OPP), biaxially orientated polypropylene (BOPP), cast polypropylene (CPP), polyamide (PA) such as nylon, polyvinyl chloride (PVC), or combinations thereof; cellulose; glass; plastic; metal and metal foils; textiles; paper; corrugated paperboard, cardboard, and equivalent recycled analogues, or combinations thereof; ceramics; foodstuffs and pharmaceutical preparations; or combinations thereof, e.g. polymer lined paper. The polymer and recycled polymer materials may be in the form of polymer film substrates.

Examples of suitable substrates within which the composition may be incorporated include, but are not limited to: polymers and recycled polymer materials such as polyethylene terephthalate (PET), polyethylene (PE), low density polyethylene (LDPE), high density polyethylene (HDPE), polystyrene (PS), polypropylene (PP), orientated polypropylene (OPP), biaxially orientated polypropylene (BOPP), cast polypropylene (CPP), polyamide (PA) such as nylon, polyvinyl chloride (PVC), or combinations thereof; and any thermoplastic material such as plastic; or combinations thereof. The polymer and recycled polymer materials may be in the form of polymer film substrates.

Preferably, the substrate to which the composition is applied to or incorporated within is a polymer film. Preferably, the substrate is colourless (i.e. transparent and translucent), off-white or white. More preferably, the substrate is colourless, off-white or white, and a polymer film.

The composition according to the second aspect of the present invention or the substrate according to the third aspect of the present invention may be suitable for end use as labels (adhesive and wraparound) and/or in, for example, fast- moving consumer goods; packaging such as disposable packaging including food and hot or cold beverage containers; hygiene and personal care product packaging such as shampoo bottles; cosmetic product packaging; medical and diagnostic devices and associated packaging; and outdoor products such as signage.

It will be appreciated by a skilled person that the substrate to which the composition has been applied to or incorporated within may itself be applied to a further substrate. Examples of further substrates include, but are not limited to the following: polymers and recycled polymer materials such as polyethylene terephthalate (PET), polyethylene (PE), low density polyethylene (LDPE), high density polyethylene (HDPE), polystyrene (PS), polypropylene (PP), orientated polypropylene (OPP), biaxially orientated polypropylene (BOPP), cast polypropylene (CPP), polyamide (PA) such as nylon, polyvinyl chloride (PVC), or combinations thereof; cellulose; glass; plastic; metal and metal foils; textiles; paper; corrugated paperboard, cardboard, and equivalent recycled analogues, or combinations thereof; ceramics; foodstuffs and pharmaceutical preparations; or combinations thereof, e.g. polymer lined paper. The polymers and recycled polymer materials may be in the form of polymer film substrates.

Preferably, the substrate comprises an additional adhesive layer. It will be appreciated that this additional adhesive layer is operable to apply the substrate to a further substrate or any other material and is therefore on an exterior surface of the substrate. The adhesive layer may cover all, substantially all, or part of the surface area of an exterior surface of the substrate. When the composition is applied to the substrate, the additional adhesive layer is preferably on an exterior surface of the substrate other than that to which the composition is applied.

Preferably, the composition according to the second aspect of the present invention is applied to the substrate.

When the composition according to the second aspect of the present invention is applied on a substrate, the substrate may further comprise a one or more additional component either incorporated within or applied to the substrate. Preferably, the further one or more additional component is applied to the substrate. If the further one or more additional component is applied to the substrate, this may be in a layer on the substrate formed from a composition comprising the one or more additional component, the composition being as defined above for the composition according to the first aspect of the present invention, the deactivatable component replaced by the further one or more additional component. This layer comprising the further one or more additional component may be applied to the substrate underneath the composition applied to the substrate, or applied over the composition applied on the substrate. If a one or more additional compound is present in the composition according to the second aspect of the present invention, the further one or more additional compound in the separate composition will be different. By different is meant that the one or more additional component in the composition according to the present invention and the further one or more additional component are selected either from different groups of (a) to (e) defined above, or are selected from the same group of (a) to (e), but are selected so as to be different compounds in that group, e.g. two different leuco dyes. Preferably, the one or more additional component in the composition according to the second present invention and the further one or more additional component are selected from different groups of (a) to (e) as defined above. Preferably, the additional component is a leuco dye or oxyanion of a multivalent metal and applied to the substrate as a composition comprising an additional component.

Thus, according to a fourth aspect of the present invention, there is provided a method of forming a substrate comprising applying to or incorporating within the substrate the composition according to the second aspect of the present invention.

The composition may be applied to the substrate by any suitable method. Methods of applying the composition to a substrate will be well known to a person skilled in the art. Suitable application methods include, but are not limited to the following: flexographic printing, gravure printing, screen printing, offset printing and meyer bar coating. The composition may be applied to all, substantially all or part of the surface area of an exterior surface of the substrate. The composition may be applied on the substrate to any suitable coat weight dependent upon both the substrate to which the composition is applied and the application method. Preferably, the composition is applied to a coat weight of from 0.1 to 50 gsm (grams per square metre), more preferably from 0.1 to 25 gsm and most preferably, 0.1 to 15 gsm. This coat weight is per individual layer of the composition that is applied to the substrate.

The coat weight may be measured by any suitable method. Suitable measuring methods will be well known to those skilled in the art. Preferably, the coat weight is measured by weighing the same area of substrate with and without the composition applied thereto, and comparing the two weights.

The composition may be applied to the substrate as a single layer or as part of a multi-layer system. The composition may be applied to the substrate as an undercoat or an overcoat, on top of a primer or as a primer layer. The composition may be applied to the substrate once or multiple times. The composition may be applied to at least part or all of an exterior surface of the substrate. As discussed above in relation to the third aspect of the present invention, a layer comprising a one or more additional component may be applied underneath the composition applied to the substrate, or applied over the composition applied on the substrate. The composition according to the present invention may be incorporated within the substrate by any suitable method. Methods of incorporating the composition within a substrate will be well known to a person skilled in the art. Suitable incorporation methods include, but are not limited to: extrusion methods including melt extrusion; injection molding; blow molding; compression molding; film insert molding; gas assisted molding; rotational molding; structural foam molding; thermoforming; and combinations thereof.

It will be appreciated by a skilled person that the composition may be incorporated within the substrate on its own or as part of a solid and/or liquid masterbatch. The composition may be incorporated within a substrate to any suitable weight percentage of the total solid weight of the substrate. Preferably, the substrate comprises 0.001 to 50 % of the composition incorporated within, based on the total solid weight of the substrate. More preferably, the substrate comprises 0.002 to 30 % of the composition incorporated within, based on the total solid weight of the substrate. Most preferably, the substrate comprises 0.003 to 20 % of the composition incorporated within, based on the total solid weight of the substrate.

Preferably, the composition according to the second aspect of the present invention is applied to the substrate.

The application to, or incorporation of the composition within the substrate enables an image to be formed on or within the substrate.

According to a fifth aspect of the present invention, there is provided a method of forming colour on or within a substrate comprising a composition applied to or incorporated within, the composition comprising a deactivatable component capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an applied transition stimulus, wherein the deactivatable component can be deactivated, either before or after transitioning, by application of a deactivation temperature, such that subsequent transitioning cannot occur, and wherein the method comprises applying to the composition on or within the substrate, the applied transition stimulus and deactivation temperature as required to develop a coloured state of the deactivatable component of the composition.

According to a sixth aspect of the present invention, there is provided a method of forming an image on or within a substrate comprising a composition applied to or incorporated within, the composition comprising a deactivatable component capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an applied transition stimulus, wherein the deactivatable component can be deactivated, either before or after transitioning, by application of a deactivation temperature, such that subsequent transitioning cannot occur, and wherein the method comprises applying to the composition on or within the substrate, the applied transition stimulus and/or deactivation temperature as required to selectively develop the non-coloured and/or the coloured states of the deactivatable component at localised positions of the composition, and thereby create an image on or within the substrate.

It will be appreciated that the non-coloured and coloured states of the deactivatable component may be present at different localised positions of the composition. The coloured states of the deactivatable component may be selectively developed at localised positions.

Suitable means for applying the applied transition stimulus and deactivation temperature are as discussed above.

It will further be understood by a skilled person that the application of the applied transition stimulus and/or the deactivation temperature to the composition, will be conducted in the appropriate order required to form the desired image. It will also be appreciated that if the composition comprises one or more additional component, the method of forming an image on the substrate comprising the composition includes the application of an additional applied stimulus or additional temperature to effect the transition of the one or more additional component from its non-coloured state to a coloured state. If the composition comprises the one or more additional component, it will be further understood by a skilled person that the application of the applied transition stimulus and/or deactivation temperature, and additional applied stimulus or additional temperature, will be conducted in the appropriate order required to selectively develop the non-coloured and/or coloured states of the deactivatable component and one or more additional component at localised positions of the composition. If the composition comprises the one or more additional component, it will be appreciated by a skilled person that the relationship between the deactivation temperature and additional temperature will vary dependent upon the colours required in the image that is to be formed. It will further be appreciated by a skilled person that the relationship between the wavelengths of the applied transition stimulus and additional applied stimulus will vary dependent upon the colours required in the image that is to be formed. Suitable means for applying the additional applied stimulus and additional temperature are as discussed above.

It will be understood by a skilled person that more than one of the applied transition stimulus, deactivation temperature, additional applied stimulus or additional temperature may be applied at the same localised position. For example, in order to form a colour resulting from the mixing of two colours (i.e. the mixing of the colours of a coloured state of the deactivatable component and a coloured state of the one or more additional component of a different colour) the applied transition stimulus and deactivation temperature and the additional applied stimulus or additional temperature may be applied at that particular localised position.

Optionally, a separate conductive source of temperature may also be provided to the composition before, during or after the formation of the image. Conductive sources of temperature include, but are not limited to the following: sources of steam and hot air, lamps, heat tunnels, LED(s), thermal print heads, hotplates, thermal conductors, hot liquids, and heated substrates.

According to a seventh aspect of the present invention, there is provided a use of the composition according to the second aspect of the invention in the formation of colour on or within a substrate.

According to an eighth aspect of the present invention, there is provided a use of the composition according to the second aspect of the invention in the formation of an image on or within a substrate.

According to a ninth aspect of the present invention, there is provided a substrate having applied thereon a plurality of discrete layers, wherein at least one of the discrete layers comprises a deactivatable component capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an applied transition stimulus, wherein the deactivatable component can be deactivated, either before or after transitioning, by application of a deactivation temperature, such that subsequent transitioning cannot occur; and wherein at least one of the discrete layers comprises one or more additional component capable of transitioning from a non-coloured state to a coloured state, the transition being effected by the application of an additional applied stimulus or additional temperature; wherein, if formed, the coloured state of the deactivatable component and the one or more additional component are different in colour, and the discrete layer comprising the deactivatable component is a different layer to the discrete layer comprising the one or more additional component.

In the ninth aspect of the present invention, the deactivatable component and one or more additional component are as defined above throughout the first to eighth aspects of the present invention. In addition, the applied transition stimulus, deactivation temperature, additional applied stimulus and additional temperature are as defined above throughout the first to eighth aspects of the present invention. It will further be appreciated that the substrate according to the ninth aspect of the present invention is based upon the substrate according to the third aspect of the present invention, the substrate according to the third aspect of the present invention having a composition layer applied to or incorporated within and the substrate according to the ninth aspect of the present invention having a plurality of discrete layers applied thereon.

The plurality of discrete layers may comprise one or more additional layers. Suitable additional layers may be selected from, but not limited to: thermal insulating layers; polymer layers; radiation blocking layers such as layers comprising UV absorbing components or layers comprising UV absorbing components; primers; adhesion promoting layers; quenching layers; layers comprising hindered amine light stabilisers; overprint varnish layers; barrier layers; diffusion barrier layers; and combinations thereof.

It will be appreciated that the plurality of discrete layers may comprise more than one of the one or more additional components. The plurality of discrete layers may further comprise a second of a one or more additional component. This second of a one of more additional component may be present in the discrete layer comprising the deactivatable component, the different discrete layer comprising the one or more additional component, or a separate different discrete layer of the plurality of discrete layers. Preferably, the second of the one or more additional component is present in a separate different discrete layer of the plurality of discrete layers. Accordingly, the substrate may comprise a first discrete layer comprising the deactivatable component, a second different discrete layer comprising a one or more additional component, and a third different discrete layer comprising the second of a one or more additional component. It will be understood that the one or more additional component and the second of a one or more additional component will be selected dependent upon the colours required, and will be different. By different is meant that the two components are selected either from different groups of (a) to (e) as defined above, or are selected from the same group (a) to (e), but are selected so as to be different compounds in that group, e.g. two different leuco dyes.

Preferably, the plurality of discrete layers comprises a deactivatable component and a leuco dye, the two components being in different discrete layers.

Preferably, the plurality of discrete layers comprises a deactivatable component, a leuco dye, and an oxyanion of a multivalent metal. Preferably, the three components are each present in a different discrete layer.

Preferably, the plurality of discrete layers comprises a deactivatable component, a pyrazole (thio)semicarbazone compound, and an oxyanion of a multivalent metal. Preferably, the three components are each present in a different discrete layer.

Preferably, the plurality of discrete layers comprises a deactivatable component and a keto acid compound, the two components being in different discrete layers.

Preferably, the plurality of discrete layers comprises a deactivatable component and a compound formed from a salicylic ketone or salicylic aldehyde compound, the two components being in different discrete layers. It will be further appreciated that the discrete layer comprising the deactivatable component may be formed of a composition applied to the substrate. In this regard, the composition is as defined above for the second aspect of the present invention. The one or more additional component present in a different discrete layer of the plurality of discrete layers applied to the substrate according to the ninth aspect of the present invention may be present as a composition that forms the different layer of the plurality of discrete layers. When the one or more additional component is present in a composition in a separate layer of the plurality of discrete layers, the one or more additional component may be present in any suitable amount, preferably from 5 to 60% of the total solid weight of the composition, more preferably from 5 to 50%, or from 5 to 35% of the total solid weight of the composition, or even from 5 to 15% of the total solid weight of the composition. Such compositions are formulated with other components such as NIR absorbers, binders, solvents and additives as defined above in relation to the composition of the second aspect of the present invention, the deactivatable component being replaced by the one or more additional component.

It will be appreciated by a skilled person that if the plurality of discrete layers comprises one or more additional layers and these one or more additional layers are positioned between the discrete layer comprising the deactivatable component and the discrete layer comprising the one or more additional component, the one or more additional layers mean that the applied transition stimulus and/or deactivation temperature and additional applied stimulus or additional temperature can be applied to the substrate from both sides in order to form multi-coloured images, the two sides being defined by the one or more additional layers.

It will further be appreciated that if the one or more additional component is accompanied by an acid- or base-generating agent, the acid- or base-generating agent will be the same discrete layer comprising the one or more additional component.

The plurality of discrete layers may have any suitable overall coat weight. Preferably, the plurality of discrete layers individually have a coat weight as set out above in relation to the composition according to the second aspect of the present invention. Further, preferably the plurality of discrete layers have an overall coat weight (encompassing all layers) of less than 100 gsm (grams per square metre), more preferably less than 50 gsm, and most preferably less than 30 gsm. It will be appreciated by a skilled person that the overall coat weight of the plurality of discrete layers will be dependent upon the layer formation and substrate.

The substrate according to the ninth aspect of the present invention may be suitable for end use as labels (adhesive and wraparound) and/or, in fast-moving consumer goods; packaging such as disposable packaging including food and hot or cold beverage containers; hygiene and personal care product packaging such as shampoo bottles; cosmetic product packaging; medical and diagnostic devices and associated packaging; and outdoor products such as signage.

The plurality of discrete layers may be applied to any suitable substrate. It will be appreciated by a skilled person that the layer structure of the plurality of discrete layers may vary depending on the substrate to which it is to be applied. The substrates to which the plurality of discrete layers may be applied are as described above in relation to the substrate according to the third aspect of the present invention

Examples of suitable substrates to which the plurality of discrete layers may be applied to, include, but are not limited to: polymers and recycled polymer materials such as polyethylene terephthalate (PET), polyethylene (PE), low density polyethylene (LDPE), high density polyethylene (HDPE), polystyrene (PS), polypropylene (PP), orientated polypropylene (OPP), biaxially orientated polypropylene (BOPP), cast polypropylene (CPP), polyamide (PA) such as nylon, polyvinyl chloride (PVC), or combinations thereof; cellulose; glass; plastic; metal and metal foils; textiles; paper; corrugated paperboard, cardboard, and equivalent recycled analogues, or combinations thereof; ceramics; foodstuffs and pharmaceutical preparations; or combinations thereof, e.g. polymer lined paper. The polymers and recycled polymer materials may be in the form of polymer film substrates. Preferably, the substrate to which the plurality of discrete layers are applied is a polymer film substrate. Preferably, the substrate is colourless (i.e. transparent or translucent), off-white or white. Preferably the substrate is colourless, and is a polymer film substrate.

It will be appreciated by a skilled person that the substrate to which the plurality of discrete layers have been applied to may itself be applied to a further substrate. Examples of further substrates include, but are not limited to the following: polymers and recycled polymer materials such as polyethylene terephthalate (PET), polyethylene (PE), low density polyethylene (LDPE), high density polyethylene (HDPE), polystyrene (PS), polypropylene (PP), orientated polypropylene (OPP), biaxially orientated polypropylene (BOPP), cast polypropylene (CPP), polyamide (PA) such as nylon, polyvinyl chloride (PVC), or combinations thereof; cellulose; glass; plastic; metal and metal foils; textiles; paper; corrugated paperboard, cardboard, and equivalent recycled analogues, or combinations thereof; ceramics; foodstuffs and pharmaceutical preparations; or combinations thereof, e.g. polymer lined paper. The polymers and recycled polymer materials may be in the form of polymer film substrates.

Preferably, the substrate to which the plurality of discrete layers has been applied comprises an additional adhesive layer. It will be appreciated that this additional adhesive layer is operable to apply the substrate to a further substrate and is therefore on an exterior surface of the substrate. The adhesive layer may cover all, substantially all, or part of the surface area of an exterior surface of the substrate.

Thus, according to a tenth aspect of the present invention there is provided a method of forming the substrate according to the ninth aspect of the present invention, the method comprising applying to a substrate the plurality of discrete layers.

It will be appreciated that the method of forming the substrate according to the tenth aspect of the present invention is as defined above for the fourth aspect of the present invention. The plurality of discrete layers may be applied to the substrate by any suitable method. Methods of applying the multi-layered product to a substrate will be well known to a person skilled in the art. Suitable application methods include, but are not limited to the following: flexographic printing, gravure printing, screen printing, offset printing and meyer bar coating. The plurality of discrete layers may be applied to all, substantially all or part of the surface area of the substrate. The plurality of discrete layers is applied to the substrate layer by layer as required.

The application of the plurality of discrete layers to the substrate enables an image to be formed on or within the substrate.

Thus, according to an eleventh aspect of the present invention, there is provided a method of forming colour on the substrate according to the ninth aspect of the present invention, the method comprising applying to the substrate, the applied transition stimulus and deactivation temperature, and additional applied stimulus or additional temperature as required to develop a coloured state of the deactivatable component and the one or more additional component.

According to a twelfth aspect of the present invention, there is provided a method of forming an image on a product according to the ninth aspect of the present invention, the method comprising applying to the substrate, the applied transition stimulus and deactivation temperature as required to selectively develop the non-coloured and/or the coloured states of the deactivatable component and one or more additional component at localised positions, and thereby create an image on or within the substrate.

It will be appreciated that the methods of forming colour and an image according to the eleventh and twelfth aspects of the present invention require similar considerations to those defined above for the fifth and sixth aspects of the present invention.

The application of the applied transition stimulus and/or deactivation temperature, and additional applied stimulus or additional temperature, will be conducted in the appropriate order as required to selectively develop the non- coloured and/or coloured states of the deactivatable component and the one or more additional component at localised positions to create an image. The coloured states of the deactivatable component and the one or more additional component may be selectively developed at localised positions. Multi-coloured images can be formed. Suitable means for applying the applied transition stimulus, deactivation temperature, additional applied stimulus and additional temperature are as defined above.

It will be understood by a skilled person that more than one of the applied transition stimulus and/or deactivation temperature and additional applied stimulus or additional temperature may be applied at the same localised position. For example, in order to form a colour resulting from the mixing of two colours (i.e. the mixing of the colours of a coloured state of the deactivatable component and a coloured state of a one or more component of a different colour), the applied transition stimulus and deactivation temperature, and additional applied stimulus or additional temperature may be applied at that particular localised position of the substrate.

It will be appreciated by a skilled person that the ordering of the plurality of discrete layers on the substrate according to the ninth aspect of the present invention can have an effect on colour formed. When the means used to apply the applied transition stimulus, deactivation temperature, additional applied stimulus or additional temperature is a laser source(s), the fluence received by each layer varies dependent upon the position of the deactivatable component and the one or more additional component in the layer structure of the plurality of discrete layers relative to the means.

It will further be appreciated by a skilled person that dependent upon the required image to be formed, the relationship between the applied transition stimulus and/or deactivation temperature and the additional applied stimulus or additional temperature will vary. The specific applied transition stimulus and/or deactivation temperature and additional applied stimulus or additional temperature will be selected dependent upon the colours required in the image to be formed so as to facilitate formation of the desired image. Optionally, a separate conductive source of temperature may be provided to the composition before, during or after the formation of the image. Conductive sources include, but are not limited to the following: sources of steam and hot air, lamps, heat tunnels, LED(s), thermal print heads, hotplates, thermal conductors, hot liquids and heated substrates.

It will be appreciated by a skilled person that the radiation applied to the compositions or substrates disclosed herein, whether by a laser source(s) or flood illumination, is applied using an apparatus suitable for such purpose, i.e. suitable for calculating the radiation required relating to the different stimuli and temperatures required to produce a desired image and applying it to a composition or substrate or a substrate comprising a plurality of discrete layers applied thereon. It will be appreciated that the apparatus will be programmed to effect the application of the different stimuli and temperatures to the compositions or substrates in the required order and facilitate the formation of an image.

Chemical Definitions

The term "Ci-i ₈ alkyl" demotes a straight or branched saturated alkyl group having from 1 to 18 carbon atoms; optionally "C _{M S} alkyl" groups can contain some degree of unsaturation (partial unsaturation) i.e. may contain one or more alkene/alkenyl moiety(s). For parts of the range C _{M S} alkyl, all sub-groups thereof are contemplated, such as C _{M O} alkyl, C _{5-i 5} alkyl, C _{5-i 0} alkyl, and Ci _-6 alkyl. Examples of said Ci _-4 alkyl groups include methyl, ethyl, n-propyl, iso- propyl, n-butyl, iso-butyl, sec-butyl, and tert-butyl. The alkyl groups may be optionally substituted with one or more functional groups, including C _{M S} alkyl groups, "C _6- 12 aryl", and "C _{M S} alkoxy", halogen, and "C _3-i8 cycloalkyl".

The term "C _6- 12 aryl" denotes a monocyclic or polycyclic conjugated unsaturated ring system having from 6 to 12 carbon atoms. For parts of the range C _6- 12 aryl, all sub-groups thereof are contemplated, such as C _6-i o aryl, C10-12 aryl, and C ₆ -s aryl. An aryl group includes condensed ring groups such as monocyclic ring groups, or bicyclic ring groups. Examples of C _6- 12 aryl groups include phenyl, biphenyl, indenyl, naphthyl or azulenyl. Condensed rings such as indan and tetrahydro naphthalene are also included in the C _6- 12 aryl group. The aryl groups may be optionally substituted with other functional groups. The aryl groups may be optionally substituted with one or more functional groups, including C _{M S} alkyl groups, halogen, and "C _{M S} alkoxy". The aryl groups may be substituted with these substituents at a single position on their unsaturated ring system, or may be substituted with these substituents at multiple positions on their unsaturated ring system.

The term "C _{M S} alkoxy" denotes a straight of branched C _{M S} alkyl group which is attached to the remainder of the molecule through an oxygen atom. For parts of the range C _{M S} alkoxy, all sub-groups thereof are contemplated such as C _{M O} alkoxy, C _{5-i 5} alkoxy, C _5-i0 alkoxy, and Ci _-6 alkoxy. Examples of said Ci _-4 alkoxy groups include methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, iso-butoxy, sec-butoxy, and tert-butoxy. The alkoxy groups may be optionally substituted with other functional groups. The alkoxy groups may be optionally substituted with one or more functional groups, including C _{M S} alkyl groups, "C _6- 12 aryl", and "Ci-is alkoxy", halogen, and "C _3-i8 cycloalkyl".

The term "C _3-i8 cycloalkyl" denotes a non-aromatic, saturated or partially saturated (i.e. may contain one or more alkene or alkenyl moiety(s)) monocyclic ring system having from 3 to 18 carbon atoms. For parts of the range C _{3-i 8} cycloalkyl, all sub-groups thereof are contemplated, such as C _3-8 cycloalkyl, C _{5-i 5} cycloalkyl, and C _5-i0 cycloalkyl. Examples of suitable C _3-i0 cycloalkyls include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl. The cycloalkyl groups may be optionally substituted with other functional groups. The cycloalkyl groups may be optionally substituted with one or more functional groups, including Ci _-20 alkyl groups, "C _5-2 o aryl", "Ci _-20 alkoxy", "hydroxylCi _-2 o alkoxy" and "C _{3-i 8} cycloalkyl".

The terms“unsaturated” and“partially saturated” refer to rings wherein the ring structure(s) contains atoms sharing more than one valence bond i.e. the ring contains at least one multiple bond e.g. a C=C, CºC or N=C bond. The term “fully saturated” refers to rings where there are no multiple bonds between ring atoms. Optional” or “optionally” means that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances in which it does not.

"Halogen" refers to fluorine, chlorine, bromine or iodine.

The term "heterocycle" and "heterocyclic ring" denotes a non-aromatic, saturated or partially saturated monocyclic or polycylic ring system having from 4 to 18 ring atoms in which one or more of the ring atoms is not carbon, e.g. nitrogen, sulphur or oxygen. The said ring system may be attached to the rest of the molecule through either a heteroatom or a carbon atom of the ring system. Examples of heterocyclic groups include but are not limited to: piperidinyl, morpholinyl, homomorpholinyl, azepanyl, piperazinyl, oxo-piperazinyl, diazepinyl, tetrahydropyridinyl, tetrahydropyranyl, pyrrolidinyl, tetrahydrofuranyl and dihydropyrrolyl.

The terms “heteroaryl” and “heteroaromatic ring” denote a monocyclic or polycyclic hetero-aromatic group comprising 5 to 18 atoms in which one or more of the atoms are other than carbon, such as nitrogen, phosphorus, sulphur or oxygen. The said hetero-aromatic ring may be attached to the rest of the molecule through either a heteroatom or a carbon atom of the ring system. Examples of heteroaryl groups include but are not limited to furyl, pyrrolyl, thienyl, oxazolyl, isoxazolyl, oxadiazolyl, imidazolyl, oxatriazoly, thiazolyl, isothiazolyl, tetrazolyl, pyrazolyl, pyridinyl, pyrimidinyl, pyridazinyl, pyrazinyl, triazinyl and thiadiazolyl. In some embodiments, the heteroaryl group contains at least one ring nitrogen atom. The nitrogen atoms in the heteroaryl groups can be basic, as in the case of an imidazole or pyridine, or essentially non-basic as in the case of an indole or pyrrole nitrogen. In general the number of basic nitrogen atoms present in the heteroaryl group, including any amino group substituents of the ring, will be less than five.

The term “cyclic amino group” refers to a non-aromatic, fully saturated or partially unsaturated monocyclic ring system having from 4 to 18 ring atoms in which one of the ring atoms is nitrogen and the group is attached to the rest of the molecule via this nitrogen atom. In such cyclic amino groups, one or more of the remaining ring atoms may be other than carbon, such as nitrogen, sulphur or oxygen. Examples of such cyclic amino groups include piperidine (1 -piperidinyl), pyrrolidine (1 -pyrrolidinyl), pyrrolidone, morpholine or piperazine.

By "secondary amino group" is meant an amine group formed by replacement of two of the hydrogen atoms in ammonia by groups or atoms other than the hydrogen atoms, the group being attached to the rest of the molecule by the bond other than the two joining the two groups or atoms replacing the hydrogen atoms to the nitrogen atom.

All of the features contained herein may be combined with any of the above aspects and in any combination.

For a better understanding of the present invention, and to show embodiments of the same may be carried into effect, reference will now be made, by way of example, to the following experimental data.

Examples

Specific Examples of the Synthesis of Deactivatable Components According to the Present Invention

Synthesis of di-tert-butyl(((docosa-10,12-divnedioyl)bis(azanediyl))bis(e thane- 2,1 -diyl))dicarbamate

1 . Weigh docosa-10,12-diynedioic acid (DCDA) (27.6 mmol, 1 equiv.) into a beaker.

2. Dissolve DCDA in THF (200 ml_) and stir for 10 minutes. 3. Meanwhile weigh 3-(((ethylimino)methylene)amino)-N,N-dimethylpropan-1 - amine hydrochloride (EDAC) (57.9 mmol 2.1 equiv.) into a round bottom flask fitted with a stirrer bar.

4. Weigh N,N-dimethylpyridin-4-amine (DMAP) (0 2.76 mmol, 0.1 equiv) into the round bottom flask.

5. Weigh tert-butyl (2-aminoethyl)carbamate (57.9 mmol, 2.1 equiv.) into the round bottom flask.

6. Add THF (50 ml_) to the round bottom flask and stir the solids creating a white suspension.

7. Weigh and flute a filter paper.

8. Filter the DCDA solution into the round bottom flask using the pre-weighed filter paper.

9. Dry and weigh the used filter paper to calculate exact quantity of DCDA used.

10. Add the filtrate to the above reaction mixture at room temperature and stir overnight.

1 1 . Vacuum filter solids on paper to obtain an off-white solid (crop 1 ).

12. Transfer the solids (crop 1 ) to a beaker and slurry for 2 hours in water (200 ml_).

13. Concentrate the filtrate using a rotary evaporator resulting in a white solid (crop 2).

14. Slurry this solid (crop 2) with 250 ml_ of de-ionised water for 1 hour.

15. Vacuum filter crop 1 on paper.

16. Stir the solids obtained (crop 1 ) with 200 mL of acetone for 1 hour.

17. Vacuum filter crop 2 on paper.

18. Stir the solids obtained (crop 2 with 200 mL of acetone for 1 hour.

19. Vacuum filter crop 1 on paper to obtain off-white solid and leave to air dry overnight.

20. Vacuum filter crop 2 on paper to obtain off-white solid and leave to air dry overnight.

21 . Dry both crop 1 & 2 further at 20 °C in a vacuum oven for 1 hour, and combine crops 1 & 2 to obtain resulting solids (10.7 g, 60%). Synthesis of di-tert-butyl 2,2'-(tetradeca-6,8-divnedioyl)bis(hvdrazine-1 - carboxylate

d t ~tert~ butyl 2: , 2'- (tet ra deca-b , S-di y nedioyi ) bt s ( hyd raztne- 1 -ca rfaoxy late

1. Tetradeca-6,8-diynedioic acid (40 mmol, 1.0 equiv.) was stirred in tetrahydrofuran (THF) (100 equiv.) in a 500 ml_ round bottom flask.

2. Triethyl amine (87.9 mmol, 2.2 equiv.) and ethyl chloroformate (87.9 mmol, 2.2 equiv) were added to the above stirring mixture.

3. The reaction mixture was stirred for 1 hour.

4. The resultant precipitate was removed by vacuum filtration on paper.

5. The filtrate was added to a solution of tert-butyl carbazate (87.9 mmol, 2.2 qquiv.) and N-methylmorpholine (132 mmol, 3.3 equiv.) in THF (20 ml_) in a 500 ml_ round bottom flask at room temperature.

6. The reaction was wrapped in tin foil and stirred.

7. The reaction mixture was concentrated using rotary evaporator to afford a light brown syrup.

8. The residue was dissolved in Acetone (20 ml_) and poured into a beaker containing Dl water (40 ml_) causing a precipitate to form.

9. The suspension was stirred for 1 hour at room temperature.

10. The solids were vacuum filtrated on paper to afford a white solid.

1 1. The solids were stirred with 100 ml_ de-ionised water for 1 hour.

12. The solids were vacuum filtered on paper and allowed to air dry overnight.

13. This white solid material was dried again at 20 °C in a vacuum oven for 1 hour (8.84 g, 71 %).

Colour Formation Using Deactivatable Components According to the Present Invention

For each of the examples, unless otherwise stated, the natural state (non- coloured state) of the deactivatable component and one or more additional components is either off-white or white. For each of the examples, unless otherwise stated, the 10.6 pm C0 ₂ laser is set at a speed of 2600- 5350 mm/s and at 38% power. The speed or power of the laser can be altered to vary the fluence applied by the laser source. Marking speeds within the 2600-5350 mm/s range are 2600, 2975, 3325, 3600, 3850, 4100, 4300, 4750, 5050 and 5350 mm/s.

Example 1

A composition comprising a deactivatable component was formulated according to Table 3, using the millbase formulations of Tables 1 and 2. All amounts are provided in weight percentages (wt%).

Di-tert-butyl(((docosa-10, 12-diynedioyl)bis(azanediyl))bis(ethane-2, 1 - diyl))dicarbamate was synthesised as set out above.

Table 1 - Millbase Formulation of Deactivatable Component

Table 2 - Millbase Formulation of NIR absorber

Table 3

A layer of the composition comprising a deactivatable component was applied to a PET substrate using a 16 pm K-bar applicator and dried with a warm air stream.

Following application to the substrate, the deactivatable component is in its non- coloured state. An applied transition stimulus was applied by flood illumination using a 254 nm low pressure mercury lamp to form a red first coloured state of the deactivatable component across the whole composition. Upon application of a deactivation temperature of around 125 to 130 °C to the red background at localised positions using a 1070 nm NIR fibre laser, the deactivable component transitions from the red first coloured state to a second black coloured state at these localised positions. The deactivatable component is deactivated at these localised positions and will not undergo any subsequent transition. It is noted that the intensity of the black colour formed can be varied by varying the fluence applied by the laser. Upon further application of UV radiation by flood illumination using a germicidal lamp, the substrate visually remains the same with the deactivatable component remaining in the black coloured state, i.e. not undergoing any subsequent transition.

Alternatively, prior to the application of the applied transition stimulus (flood illumination using a 254 nm low pressure mercury lamp), a deactivation temperature of around 125 to 130 °C was applied at localised positions using a 1070 nm NR fibre laser. The deactivatable component is deactivated at these localised positions and will not undergo any subsequent transitions. Upon application of the applied transition stimulus through flood illumination using a 254 nm low pressure mercury lamp, the red first coloured state of the deactivatable component is formed in the composition, but the localised positions of the composition at which the deactivatable component has been deactivated are not effected and remain in the non-coloured state and will not undergo any subsequent transition.

A multi-coloured image displaying red and black can therefore be formed. In addition, the non-coloured state of the diacetylene component can form part of the multi-coloured image.

Example 2

A composition comprising a deactivatable component was formulated according to Table 6, the millbase formulations of Tables 4 and 5. All amounts are provided in weight percentages (wt%).

Di-tert-butyl 2,2'-(tetradeca-6,8-diynedioyl)bis(hydrazine-1 -carboxylate was synthesised as set out above. Table 4 - Millbase Formulation of Deactivatable Component

Table 5 - Millbase Formulation of NIR absorber

Table 6

A layer of the composition comprising a deactivatable component formulated according to Table 6 was applied to a PET substrate using a 16 pm K-bar applicator and dried with a warm air stream. Following application to the substrate, the deactivatable component is in its non- coloured state. An applied transition stimulus was applied by flood illumination using a 254 nm low pressure mercury lamp to form a red first coloured state of the deactivatable component across the whole composition.

Upon application of a deactivation temperature of around 125 to 130 °C to the red background at localised positions using a 1070 nm NIR fibre laser, the deactivatable component transitions from the red first coloured state to a second yellow coloured state at these localised positions. The deactivatable component is deactivated at these localised positions and will not undergo any subsequent transition. Upon further application of UV radiation by flood illumination using a germicidal lamp, the substrate visually remains the same with the deactivatable component not undergoing any subsequent transition.

Alternatively, prior to the application of the applied transition stimulus (flood illumination using a 254 nm low pressure mercury lamp), a deactivation temperature of around 125 to 130 °C was applied at localised positions using a 1070 nm NIR fibre laser. The deactivatable component is thus deactivated at those positions. Upon application of the applied transition stimulus through flood illumination using a 254 nm low pressure mercury lamp, the red first coloured state of the deactivatable component is formed in the composition. However, the localised positions of the composition at which the deactivatable component has been deactivated are not effected and remain in the non- coloured state and will not undergo any subsequent transition A multi-coloured image displaying red and yellow colours can therefore be formed. In addition, the non-coloured state of the diacetylene component can form part of the multi-coloured image.

General Procedure for the Synthesis of an Additional Component: Pyrazole (Thio)Semicarbazone Compound of Formula (III)

Step 1 : Synthesis of a pyrazaole ring

A hydrazine and an ethyl-3-oxo-3-propanoate are refluxed together releasing ethanol and water, and forming a pyrazalone ring product having substituents A and B on the ring. The product is purified by precipitation or recrystallization from an appropriate solvent.

Step 2: Addition of a reactive ketone substituent

The pyrazalone ring product from step 1 is reacted with an acyl chloride in the presence of calcium hydroxide under reflux. The reactive ketone product is purified by either precipitation or recrystallization from an appropriate solvent.

Step 3: Formation of the semicarbazide

The condensation of the reactive ketone product from step with a hydrazine carboxamide in the presence of an acetic acid catalyst produces the final reaction product. The product is then purified by precipitation or recrystallization from an appropriate solvent.

Specific Synthesis of An Additional Component: Pyrazole (Thio)Semicarbazone Compound of Formula (III): (E)-2-((5-hvdroxy-1 ,3-diphenyl-1 H-pyrazol-4-yl)(4- (trifluoromethyl)phenyl)methylene)-N-phenylhvdrazine-1 -carboxamide

For (E)-2-((5-hydroxy-1 ,3-diphenyl-1 H-pyrazol-4-yl)(4- (trifluoromethyl)phenyl)methylene)-N-phenylhydrazine-1 -carboxamide: A = phenyl, B = phenyl, C = phenyl substituted with CF ₃ , and D = phenyl.

Step One: Synthesis of 1 ,3-diphenyl-5-pyrazalone (DPP)

1. A 3 neck round bottom flask (rbf) fitted with a thermometer and stirrer bar is charged with Toluene (50 ml_, colourless liquid). 2. Ethyl 3-oxo-3-phenylpropanoate (100 g, 0.52 mmol, colourless liquid) is added to the round bottom flask.

3. Phenylhydrazine (56 g, 0.51 mmol, yellow liquid) is added to the round bottom flask and the mixture is stirred resulting in a pale-yellow solution. 50 ml of additional toluene is used to rinse any excess phenylhydrazine into the reaction.

4. A dean stark trap is fitted to the flask with a reflux condenser attached.

5. A heating block is used to heat the reaction solution to 110 °C.

6. The dean stark apparatus is used to remove water/ethanol and assess when the reaction has gone to completion (TLC may also be used to assess progress of reaction eluting with DCM/Heptane 4:1 ). 7. The reaction mixture is allowed to cool with stirring to avoid the formation of large clumps of product.

8. Once the reaction mixture is cool enough to handle, it is poured into a large beaker and any large product clumps are broken up with a spatula. 9. Heptane (-100 ml_) is added to the beaker and a large spatula is used to break up all the clumps rending the material into a relatively free flowing crystalline powder.

10. An additional 1.4 L of heptane is added and the product slurried overnight.

1 1. The pale-yellow solids are vacuum filtered and dried under vacuum (108.4 g, 88 %).

Step Two: Synthesis of (5-hvdroxy-1 ,3-diphenyl-1 H-pyrazol-4-yl)(4-

(trifluoromethvDphenvDmethanone Bn-DPP)

1. DPP (25.75 g, 109.0 mmol) is weighed and placed in a 3-neck round bottom flask (rbf) fitted with a stirrer, thermometer and dropping funnel. 2. 1 ,4-dioxane (300 ml_) is added and the mixture stirred until the DPP is

dissolved, giving a pale-yellow solution.

3. Calcium hydroxide (24.22 g, 326.9 mmol) is added and the suspension

stirred.

4. 4-(trifluoromethyl)benzoyl chloride (25.00 g, 1 19.9 mmol) is weighed into a beaker and dissolved in 1 ,4-dioxane (100 ml_).

5. The 4-(trifluoromethyl)benzoyl chloride solution is transferred to the dropping funnel.

6. The reaction suspension is cooled using a cold water-bath.

7. The 4-(trifluoromethyl)benzoyl chloride solution is added dropwise over 40 minutes ensuring that the reaction mixture does not exceed 50 °C. 8. The dropping funnel is replaced by a reflux condenser and the reaction mixture is heated to reflux and followed by TLC (DCM 20% EtOAc).

9. The reaction is stirred for 2 hours.

10. The reaction solution is allowed to cool back to 50 °C. 1 1. The reaction solution is poured into aqueous HCI (2 M,1.1 L, 2.18 mol) with strong stirring causing a pale-yellow precipitate to form which rapidly clumps and turns brown.

12. The suspension is stirred vigorously for approximately 2 hours.

13. The precipitate is vacuum filtered on paper and partially dried by suction giving a sandy brown solid.

14. The brown solids are transferred to a large beaker and slurried in hot I PA for around 3 hours, the solvent is allowed to cool while still slurrying.

15. The yellow solids are then vacuum filtered on paper and dried by suction for around 1 hour. 16. The yellow solids are transferred to a drying dish and dried in a vacuum oven

(30 °C) over night (36.60 g, 82.24 %).

Step Three: Synthesis of (E)-2-((5-hvdroxy-1 ,3-diphenyl-1 H-pyrazol-4-yl)(4-

(trifluoromethyl)phenyl)methylene)-N-phenylhvdrazine-1 -carboxamide

1. CF ₃ -Bn-DPP (20.08 g, 49.17 mmol) is weighed and placed into a 3-neck round bottom flask (rbf) fitted with a stirrer bar, thermometer and condenser.

2. 4-phenylsemicarbazide (8.18 g, 54.09 mmol) is weighed and placed into the round bottom flask.

3. Ethanol (200 ml_) is added to the reaction vessel and the mixture stirred.

4. Glacial acetic acid (0.1 M in ethanol, 5 ml_, 0.49 mmol) is added to the

reaction mixture. 5. The reaction mixture is heated to reflux (80 °C) and followed by TLC (DCM 40% ethylacetate).

6. The reaction kis refluxed for 6 hours and then left to cool and stand over the weekend. 7. Over the weekend a large quantity of white precipitate formed, this is vacuum filtered on paper, washed with I PA and dried by suction for an hour.

8. The solids are placed in a beaker and dried under vacuum overnight (30 °C) giving an off-white fluffy powder (22.35 g, 83.9 %).

General Procedure for the Synthesis of an Additional Component: Compound of Formula (VIII) or (IX) Formed From a Salicylic Aldehyde or Salicylic Ketone

Compound

1. The selected 2-hydroxyarylcarbonyl (aldehyde or ketone) (2.1 molar equivalent) is dissolved/suspended in ethanol (0.3 to 1.2 molar equivalent) in a 3-neck round bottom flask fitted with a dropping funnel, stirrer bar and thermometer.

2. A solution of hydrazine hydrate (35% or 79% w/v, 1.0 molar equivalent) in ethanol is prepared and placed in the dropping funnel.

3. The hydrazine hydrate solution is added with stirring over the course of 5 to 20 minutes to the solution of the 2-hydroxyarylcarbonyl. This addition may result in a small exotherm.

4. The dropping funnel is replaced with a condenser and the reaction mixture brought to reflux (80 °C).

5. The reaction mixture is refluxed with stirring for 5 hours and then left to cool overnight. 6. Once cooled, any precipitate which is formed is vacuum filtered on paper and washed with additional ethanol and optionally, additional water, to ensure the complete removal of any remaining hydrazine hydrate.

7. The collected solids may be vacuum filtered on paper and dried in a vacuum oven overnight; or the collected solids may be dissolved with heating in solvent and then precipitated by addition of further solvent, and the resulting solids vacuum filtered on paper and dried in a vacuum oven overnight; or the collected solids may be recrystallised from hot ethanol, and vacuum filtered on sintered glass and left to air dry.

It will be appreciated that the selection of the methodology in step 7 will be dependent upon the properties of the specific solids formed.

Specific Synthesis of an Additional Component: Compound of Formula (VIII) Formed From a Salicylic Aldehyde or Salicylic Ketone Compound: 2,2'-((1 E,TE)- hvdrazine-1 ,2-diylidenebis(methaneylylidene))diphenol

For 2,2'-((1 E,TE)-hydrazine-1 ,2-diylidenebis(methaneylylidene))diphenol: Xi _a , X _2a , X3 _a , X _4a , Xi _b , X2 _b , X3 _b and X _4b are C, R ¹ and R ² are hydrogen, and R ³ and R ⁴ are hydrogen. 1. A solution of salicylaldehyde (45 g, 0.37 mol) in ethanol (100 ml) was prepared in a 3-neck round bottom flask (rbf) fitted with a dropping funnel, stirrer bar and thermometer.

2. A solution of hydrazine hydrate (35 % w/v, 15.8 ml, 0.17 mol) in ethanol (50 ml) is prepared and placed in the dropping funnel. 3. The hydrazine hydrate solution is added with stirring over the course of 20 minutes to the salicylaldehyde solution resulting in a small exotherm (initial temperature 20 °C, final temperature 50 °C). 4. During the addition, the suspension thickens to the point where stirring is ineffective, therefore three additional portions of ethanol (50 ml each) are added to the flask during the addition to maintain stirring of the suspension.

5. The dropping funnel is replaced with a condenser and the reaction brought to reflux (80 °C).

6. The reaction is refluxed with stirring for 5 hours and then left to cool overnight

7. The cooled crystalline yellow precipitate that formed is vacuum filtered on paper and washed with additional ethanol.

8. The collected solids are recrystallised from hot ethanol yielding a pale yellow crystalline solid.

9. The resulting solids are vacuum filtered on sintered glass and left to air dry to yield a pale-yellow crystalline product (40.4 g, 96 %).

An Additional Component: A Keto Acid Compound of Formula (V)

Keto acid compounds of formula (V) can be purchased from Chameleon Speciality Chemicals Ltd, or formulated according to the following syntheses.

Generic Synthesis of a Keto Acid Compound of Formula (V)

The amino-phenol (1 equivalent) and anhydride (1 equivalent) are weighed into a round bottom flask fitted with a stirrer bar, thermometer and reflux condenser. The solids are suspended in toluene (0.3 to 2.0 molar solution) and refluxed for 18 hours. The reaction mixture is allowed to cool to room temperature and the solvent removed on a roto-evaporator. The product is isolated by flash column chromatography eluting with a polarity gradient from Heptane/DCM 1 :1 to DCM 20 % ethyl acetate. The column fractions are concentrated on a roto-evaporator to ~0.5 L and precipitated by adding the solution to a beaker of stirred heptane (1 to 2 L). The precipitate is vacuum filtered onto paper, dried by suction for - 10 mins then transferred to a drying dish and dried in a vacuum oven (20 °C) overnight yielding the product as a pale coloured powder. Specific Synthesis of (2-(4-(dimethylamino)-2-hvdroxybenzoyl)benzoic acid

3-(Dimethylamino)phenol (26.0 g, 190 mmol) and Phthalic anhydride (28.07 g, 189.5 mmol) were weighed into a round bottom flask fitted with a stirrer bar, thermometer and reflux condenser. The solids were suspended in Toluene (100 ml_) and reflux for 18 hours. The reaction mixture was allowed to cool to room temperature and the solvent removed on a roto-evaporator. The residue was extracted into Ethyl Acetate (500 ml_) with sonication and heating. The mixture was filtered through sintered glass. The filtrate was precipitated by addition of Heptane (500 ml_) and the dark solids vacuum filtered onto paper. The solids were dissolved in Dichloromethane (300 ml_) and passed through a silica pad eluting with dichloromethane until the filtrate ran clear. The dichloromethane solution was concentrated on a roto-evaporator to ~0.5 L and was precipitated by adding the dichloromethane solution to a beaker of stirred Heptane (1 L). The Precipitate was vacuum filtered onto paper, dried by suction for around 10 minutes then transferred to a drying dish and dried in a vacuum oven (20 °C) overnight yielding the product as a beige coloured powder (22.23 g, 77.92 mmol, 41.1 %).

Specific Synthesis of (2-(4-(diethylamino)-2-hvdroxybenzoyl)-5-nitrobenzoic acid

3-(Diethylamino)phenol (21.47 g, 129.9 mmol) and 4-nitro-phthalic anhydride (25.07 g, 129.8 mmol) were weighed into a round bottom flask fitted with a stirrer bar, thermometer and reflux condenser. The solids were suspended in toluene (100 ml_) and reflux for 18 hours. The reaction mixture was allowed to cool to room temperature and the solvent removed on a roto-evaporator. The product was isolated by flash column chromatography eluting with a polarity gradient from Heptane/DCM 1 :1 to DCM 10 % Ethyl Acetate. The column fractions were concentrated on a roto-evaporator to ~ 0.5 L and was precipitated by adding the solution to a beaker of stirred heptane (1 L). The precipitate was vacuum filtered onto paper, dried by suction for around 10 minutes then transferred to a drying dish and dried in a vacuum oven (20 °C) overnight yielding the product as a pale-yellow coloured powder (7.60 g, 21.2 mmol, 16.3 %). Specific _ Synthesis _ of _ (2,3,4,5-tetrachloro-6-(4-(diethylamino)-2- hvdroxybenzovDbenzoic acid

3-(Diethylamino)phenol (22.00 g, 131.1 mmol) and tetrachloro-phthalic anhydride (38.06 g, 131.1 mmol) were weighed into a round bottom flask fitted with a stirrer bar, thermometer and reflux condenser. The solids were suspended in toluene (100 ml_) and reflux for 18 hours. The reaction mixture was allowed to cool to room temperature and the solvent removed on a roto-evaporator. The product was isolated by flash column chromatography eluting with a polarity gradient from Heptane/DCM 1 :1 to DCM 10 % ethyl acetate. The column fractions were concentrated on a roto-evaporator to ~0.5 L and was precipitated by adding the solution to a beaker of stirred heptane (1 L). The precipitate was vacuum filtered onto paper, dried by suction for around 10 minutes then transferred to a drying dish and dried in a vacuum oven (20 °C) overnight yielding the product as a yellow coloured powder (15.63 g, 34.65 mmol, 26.02 %).

Specific Synthesis of (2,5-bis(4-(diethylamino)-2-hvdroxybenzoyl)terephthalic acid

3-(Diethylamino)phenol (39.3 g, 230 mmol) and Pyromellitic anhydride (25.0 g, 1 14.6 mmol) were weighed into a round bottom flask fitted with a stirrer bar, thermometer and reflux condenser. The solids were suspended in toluene (400 ml_) and reflux for 18 hours. The reaction mixture was allowed to cool to room temperature and the solvent removed on a roto-evaporator. The product was isolated by flash column chromatography eluting with a polarity gradient from Heptane/DCM 1 :1 to DCM 20 % ethyl acetate. The column fractions were concentrated on a roto-evaporator to ~0.5 L and was precipitated by adding the solution to a beaker of stirred Heptane (2 L). The precipitate was vacuum filtered onto paper, dried by suction for around 10 minutes then transferred to a drying dish and dried in a vacuum oven (20 °C) overnight yielding the product as a yellow coloured powder (5.84 g, 10.6 mmol, 9.29 %). Colour Formation Using Deactivatable Components and One or More Additional Components According to the Present Invention

Example 3

A composition comprising a deactivatable component was formulated according to Table 9, using a 50:50 mixture of the millbase formulations of Tables 7 and 8. All amounts are provided in weight percentage (wt%).

Di-tert-butyl 2,2'-(tetradeca-6,8-diynedioyl)bis(hydrazine-1 -carboxylate was synthesised as set out above.

Table 7 - Millbase Formulation of Deactivatable Component

Table 8 - Millbase Formulation of NIR absorber

Table 9

A composition comprising a leuco dye and acid-generating agent was formulated according to Table 12, using the millbase formulations of Tables 10 and 11 and Table 8. All amounts are in weight percentage (wt%). Table 10 - Millbase Formulation of Leuco dye

Table 11 - Millbase Formulation of Acid-Generating Agent

Table 12

A layer of the composition comprising the leuco dye and acid-generating agent was applied to a PET substrate using a 16 pm K-bar applicator. A layer of the composition comprising the deactivatable component formulated was applied on top of the layer of the composition comprising the deactivatable component in an identical manner.

(Note: The composition comprising the leuco dye and acid-generating agent and the composition comprising the deactivatable component can also be combined and applied to the substrate as a single layer, i.e. a composition according to the second aspect of the present invention).

Following application to the substrate, the deactivatable component and the leuco dye are in their non-coloured states. An applied transition stimulus was applied by flood illumination using a 254 nm low pressure mercury lamp to form a red first coloured state of the deactivatable component across the substrate. It is noted that the transition of the leuco dye from its non-coloured to a coloured state is not effected by the application of the 254 nm radiation on account of the fact that the acid-generating agent accompanying the leuco dye is a thermal acid-generating agent. The transition to a coloured state for the leuco dye is therefore only be effected by application of the additional temperature.

Upon application of a deactivation temperature of around 125 to 130 °C to the red background at localised positions using a 1070 nm NIR fibre laser, the deactivatable component transitions from the red first coloured state to a second yellow coloured state at these localised positions. The deactivatable component is deactivated at these localised positions and will not undergo subsequent transition. The application of the deactivation temperature of around 125 to 130 °C also facilitated the transition of the leuco dye from the non- coloured state to a blue coloured state (additional temperature) at these localised positions. The intensity of the colours of the coloured states of the deactivatable component and the leuco dye can be made to vary by variation of the fluence of the means used to apply the radiation. At the localised positions at which the two coloured states have been formed, i.e. the yellow coloured state of the deactivatable component and the blue coloured state of the leuco dye have been formed, the final colour displayed at these localised positions is dependent upon the intensity of each of the colours of the coloured states formed, i.e. the final colour at each of the localised positions results from the combination of the colours of the coloured states of the two components. Accordingly, blue, yellow and green colours can be formed.

Alternatively, prior to the application of the applied transition stimulus, (flood illumination using a 254 nm low pressure mercury lamp), a deactivation temperature of around 125 to 130 °C was applied at localised positions using a 1070 nm NIR fibre laser. The deactivatable component is deactivated at these localised positions. Upon application of the applied transition stimulus through flood illumination using a 254 nm low pressure mercury lamp, the red first coloured state of the deactivatable component is formed across the substrate. However, the localised positions at which the deactivatable component has been deactivated are not effected and remain off-white in the non-coloured state and will not undergo any subsequent transition

A multi-coloured image displaying red, blue, green and yellow can thus be formed. In addition, the non-coloured state of the diacetylene component can form part of the multi-coloured image.

Example 4 A composition comprising a deactivatable component was formulated according to Table 15, using the millbase formulations of Tables 13 and 14. All amounts are provided in weight percentage (wt%).

Table 13 - Millbase Formulation of Deactivatable Component

Table 14 - Millbase Formulation of NIR absorber

Table 15

A composition comprising a compound of formula (VIII) formed from a salicylic aldehyde or salicylic ketone compound and an acid-generating agent is formulation according to a 50:50 mixture of the formulations of Tables 16 and 17. Table 16 - Formulation comprising compound of formula (VIII)

Table 17 - Formulation comprising acid-generating agent

To a first PET substrate, a layer of the composition comprising the deactivatable component is applied using a 16 pm k-bar applicator. A layer of the composition comprising the compound of formula (VIII) and acid-generating agent was then applied using a 16 pm k-bar applicator over the layer of the composition comprising the deactivatable component.

To a second PET substrate, a layer of the composition comprising the compound of formula (VIII) and acid-generating agent is applied using a 16 pm k-bar applicator. A layer of the composition comprising the deactivatable component was then applied using a 16 pm k-bar applicator over the layer of the composition comprising the compound of formula (VIII) and acid-generating agent. Following application of the layers to the first and second PET substrates, the deactivatable component and the compound of formula (VIII) are in their non- coloured states. The natural state (non-coloured state) of the compound of formula (VIII) is yellow, and therefore the PET substrates display this colour.

Upon application of UV radiation by flood illumination using a 30W germicidal UV lamp for 20 seconds (applied transition stimulus), the non-coloured state of the deactivatable component transitions from the non-coloured to a first coloured state. It is noted that the compound of formula (VIII) does not transition as it is accompanied by a thermal acid-generating agent, and thus required additional temperature to facilitate a transition from the non-coloured state to a coloured state of the compound of formula (VIII). The first coloured state of the deactivatable component is blue in colour. For the first PET substrate having the deactivatable component applied first to the substrate, the colour displayed on the PET substrate appears to remain predominantly yellow, i.e. predominantly display the non-coloured state of the compound of formula (VIII). However, for the second PET substrate having the deactivatable component applied over the layer comprising the compound of formula (VIII), the colour displayed on the PET substrate is green, i.e. a mixture of the yellow displayed by the non- coloured state of the compound of formula (VIII) and the blue first coloured state of the deactivatable component. This difference is as a result of the different ordering of the layers on the PET substrate. Absorption of the applied radiation (and thus depth of colour formation) by the deactivatable component differs dependent upon its distance from the laser, i.e. the layer in which it is situated.

Following the application of the applied transition stimulus to the two PET substrates, IR radiation using a 10.6 pm C0 ₂ laser (2600-5350 mm/s, 38% power) is applied to localised positions of the substrate (additional temperature). At these localised positions, the compound of formula (VIII) transitions from its yellow non-coloured state to a coloured state. The colour of the coloured state, and the intensity thereof, can be made to vary between yellow or orange by variation of the fluence applied by the laser. It is noted that the deactivation temperature of the deactivatable component is lower than the additional temperature required to facilitate a transition of the compound of formula (VIII) from the non-coloured to a coloured state. Therefore, upon application of the IR radiation, the deactivation temperature is also reached and at these localised positions, the deactivatable component also transitions from the first blue coloured state to a red second coloured state. The deactivatable component is deactivated at these localised positions and will not undergo any subsequent transition. The intensity of the coloured state can be made to vary by variation of the fluence applied by the C0 ₂ laser. As the second coloured state of the deactivatable component is formed at the same localised position at which the coloured state of the compound of formula (VIII) has been formed, the final colour displayed at these localised positions is dependent upon the colour of the coloured state of the compound of formula (VIII), and the colour of the red second coloured state of the deactivatable component, i.e. the final colour at these localised positions results from the combination of colours of the coloured states of these two components. Accordingly, yellow and orange colours may be formed.

Alternatively, following application of the layers to the first and second PET substrates, IR radiation (additional temperature) using a 10.6 pm C0 ₂ laser (2600-5350 mm/s, 38% power) is applied at localised positions of the substrate. At these localised positions, the compound of formula (VIII) transitions from its yellow non-coloured state to a coloured state at these localised positions. The colour of the coloured state, and intensity thereof, can be made to vary between yellow or orange by variation of the fluence applied by the C0 ₂ laser. It is noted that, as discussed above, the deactivation temperature of the deactivatable component is lower than the additional temperature required to facilitate a transition of the compound of formula (VIII) from the non-coloured to a coloured state. It will therefore be appreciated that upon application of the IR radiation, the deactivation temperature will also be reached and the deactivatable component will be ‘deactivated’ at the localised positions, such that it is not capable of undergoing any subsequent transitions.

The application of the additional temperature can then be followed by the application of UV radiation by flood illumination using a 30W germicidal (254nm) lamp such that the non-coloured state of the deactivatable component transitions from the non-coloured to a first coloured state. This occurs across all of the substrate apart from the localised positions at which the coloured state of the compound of formula (VIII) has been formed and the deactivatable component ‘deactivated’. The first coloured state of the deactivatable component is blue in colour. The same difference in colour displayed by the first and second PET substrates (i.e. a green or a yellow colour displayed) is seen as described above as a result of the different ordering of the layers applied on the PET substrates. Absorption of the applied radiation (and thus depth of colour formation) by the deactivatable component differs dependent upon its distance from the laser, i.e. the layer in which it is situated.

A multi-coloured image displaying yellow, orange, and green colours can therefore be formed.

Example 5

A composition comprising a deactivatable component was formulated according to Table 15 above, using the millbase formulations of Tables 13 and 14. A composition comprising a compound of formula (VIII) formed from a salicylic aldehyde or salicylic ketone compound and an acid-generating agent is formulated according to a 50:50 mixture of the formulations of Tables 16 and 17 above.

To a paper substrate, a layer of the composition comprising the compound of formula (VIII) and acid-generating agent is applied using a 16 pm k-bar applicator. A layer of the composition comprising the deactivatable component was then applied using a 16 pm k-bar applicator over the layer of the composition comprising the compound of formula (VIII) and the acid-generating agent.

Following application of the layers to the paper substrate, the deactivatable component and the compound of formula (VIII) are in their non-coloured states. The natural state (non-coloured state) of the compound of formula (VIII) is yellow, and therefore the PET substrate displays this colour.

Upon application of UV radiation by flood illumination using a 30W germicidal UV lamp for 20 seconds (applied transition stimulus), the non-coloured state of the deactivatable component transitions from the non-coloured to a first coloured state. It is noted that the compound of formula (VIII) does not transition as it is accompanied by a thermal acid-generating agent, and thus requires additional temperature to facilitate a transition from its non-coloured state to a coloured state. The first coloured state of the deactivatable component is blue in colour, and as the layer comprising the deactivatable component is closest to the laser source, a more intense blue colour is developed as opposed to if the layer comprising the deactivatable component had been the first applied onto the substrate. The PET substrate therefore displays a green colour following application of the UV radiation, i.e. a mixture of the yellow displayed by the non- coloured state of the compound of formula (VIII) and the blue first coloured state of the deactivatable component.

Following the application of the applied transition stimulus to the substrate, IR radiation using a 10.6 pm C0 ₂ laser (2600-5350 mm/s, 5%, 10% and 38% power) is applied to localised positions of the substrate (additional temperature). At these localised positions, the compound of formula (VIII) transitions from its yellow non-coloured state to a coloured state at these localised positions. The colour of the coloured state, and intensity thereof, can be made to vary between yellow or orange by variation of the fluence applied by the laser, e.g. by varying the power of the C0 ₂ laser. It is noted that the deactivation temperature of the deactivatable component is lower than the additional temperature required to facilitate a transition of the compound of formula (VIII) from the non-coloured to a coloured state. It will therefore be appreciated that upon application of the IR radiation, the deactivation temperature will also be reached and the deactivatable component transitions from the first blue coloured state to red second coloured state. The deactivatable component is deactivated at these localised positions and will not undergo any subsequent transition. The intensity of the second coloured state of the deactivatable component can be made to vary by variation of the fluence. As the second coloured state of the deactivatable component is formed at the same localised position at which the coloured state of the compound of formula (VIII) has been formed, the final colour displayed at these localised positions is dependent upon the colour of the coloured state of the compound of formula (VIII), and the colour of the second red coloured state of the deactivatable component, i.e. the final colour at these localised positions results from the combination of colours of the coloured states of these two components. Accordingly, different orange and yellow colours may be formed.

Alternatively, following application of the layers to the paper substrate, IR radiation (additional temperature) using a 10.6 pm C0 ₂ laser (2600-5350 mm/s, 5%, 10% and 38% power) is applied at localised positions of the substrate. At these localised positions, the compound of formula (VIII) transitions from its yellow non-coloured state to a coloured state at these localised positions. The colour of the coloured state, and intensity thereof, can be made to vary between yellow or orange by variation of the fluence applied by the laser, e.g. by varying the power of the C0 ₂ laser. It is noted that, as discussed above, the deactivation temperature of the deactivatable component is lower than the additional temperature required to facilitate a transition of the compound of formula (VIII) from the non-coloured to a coloured state. It will therefore be appreciated that upon application of the IR radiation, the deactivation temperature will also be reached and the deactivatable component will be ‘deactivated’ at the localised positions, such that it is not capable of undergoing any subsequent transitions.

The application of the additional temperature can then be followed by the application of UV radiation by flood illumination using a 30W germicidal (254nm) lamp such that the non-coloured state of the deactivatable component transitions from the non-coloured to a first coloured state. This occurs across all of the substrate apart from the localised positions at which the coloured state of the compound of formula (VIII) has been formed and the non-coloured state of the deactivatable component ‘deactivated’. The first coloured state of the deactivatable component is blue in colour, and as discussed above, these areas of the substrate display a green colour on account of the combination of the colour of the non-coloured state of the compound of formula (VIII) and the coloured state of the deactivatable component.

A multi-coloured image displaying yellow, orange, and green colours can therefore be formed.

Example 6

A composition comprising a deactivatable component was formulated according to Table 15 above, using the millbase formulations of Tables 13 and 14.

A composition comprising a compound of formula (VIII) formed from a salicylic aldehyde or salicylic ketone compound and a base-generating agent is formulated according to a 50:50 mixture of the formulations of Tables 18 and 19.

Table 18 - Formulation comprising compound of formula (VIII)

Table 19 - Formulation comprising base-generating agent

To a PET substrate, a layer of the composition comprising the compound of formula (VIII) and base-generating agent is applied using a 16 pm k-bar applicator. A layer of the composition comprising the deactivatable component was then applied using a 16 pm k-bar applicator over the layer of the composition comprising the compound of formula (VIII) and the base-generating agent.

Following application of the layers to the PET substrate, the deactivatable component and the compound of formula (VIII) are in their non-coloured states. Upon application of IR radiation using a 10.6 pm C0 ₂ laser (2600-5350 mm/s, 1 %, 38% and 80% power) to localised positions of the substrate (additional temperature). At these localised positions, the compound of formula (VIII) transitions from its non-coloured state to a pale yellow coloured state at these localised positions. The intensity of the colour of the coloured state can be made to vary by altering the fluence applied by the laser, e.g. by varying the power of the C0 ₂ laser. It is noted that the deactivation temperature of the deactivatable component is lower than the additional temperature required to facilitate a transition of the compound of formula (VIII) from the non-coloured to a coloured state. Therefore, it will be appreciated that upon application of the IR radiation, the deactivation temperature is reached and the deactivatable component will be ‘deactivated’ at the localised positions, such that it is not capable of undergoing any subsequent transitions.

It is noted that if the C0 ₂ laser is applied at lower power, only the deactivation temperature will be reached and therefore the deactivatable component is deactivated at the localised positions, but the compound of formula (VIII) does not transition from the non-coloured to a pale yellow coloured state, such that the colour displayed by the substrate at the localised positions is dependent solely on the non-coloured state of the deactivatable component.

UV radiation is then applied to the substrate by flood illumination using a 30W germicidal UV lamp for 1 minute. The non-coloured state of the deactivatable component therefore transitions from the non-coloured to a first blue coloured state across the substrate except from those localised positions where the coloured state of the component of (VIII) has been formed and the deactivatable component has been‘deactivated’.

Alternatively, after application of the layers to the PET substrate, UV radiation is applied by flood illumination using a 30W germicidal lamp. The non-coloured state of the deactivatable component transitions from the non-coloured to the first blue coloured state across the whole substrate. Following application of IR radiation using a 10.6 C0 ₂ pm laser (2600-5350 mm/s, 38% power) (deactivation temperature) to localised positions of the substrate, the deactivatable component at these positions transitions from the first blue coloured state to the second red coloured state. The intensity of the red second coloured state can be varied by alteration of the fluence applied by the C0 ₂ laser. Upon application of the IR radiation, the additional temperature has also been reached and the compound of formula (VIII) also transitions from the non- coloured to a coloured state. As the second coloured state of the deactivatable component is formed at the same localised position at which the coloured state of the compound of formula (VIII) has been formed, the final colour displayed at these localised positions is dependent upon the colour of the coloured state of the compound of formula (VIII), and the colour of the second red coloured state of the deactivatable component, i.e. the final colour at these localised positions results from the combination of colours of the coloured states of these two components. Accordingly, orange and red colours may be formed.

A multi-coloured image can therefore be formed displaying yellow, blue, orange and red colours.

Example 7

A composition comprising a deactivatable component and a compound of formula (VIII) formed from a salicylic aldehyde or salicylic ketone compound and an acid-generating agent is formulated by combing 1 part of the formulation of Table 15 above, using the millbase formulations of Tables 13 and 14, with 1 part of a 50:50 mixture of the formulations of Tables 16 and 17 above.

A layer of the composition was applied onto a paper substrate (paperboard) using a 20 pm k-bar applicator.

Following application of the layer to the paper substrate, the deactivatable component and the compound of formula (VIII) are in their non-coloured states. The natural state (non-coloured state) of the compound of formula (VIII) is a pale yellow, and therefore the PET substrate displays this colour.

Upon application of IR radiation using a 10.6 pm C0 ₂ laser (2600-5350 mm/s, 38%, power) or NIR radiation using a Nd:YAG laser 1064 nm NIR laser (50% speed, 20-80% power) to localised positions of the substrate (additional temperature), the compound of formula (VIII) transitions from its non-coloured state to a coloured state at these localised positions. The colour of the coloured state, and intensity thereof, of the compound of formula (VIII) can be made to vary between yellow or orange by variation of fluence, e.g. by varying the power of the C0 ₂ or NIR laser. It is noted that the deactivation temperature of the deactivatable component is lower than the additional temperature required to facilitate a transition of the compound of formula (VIII) from the non-coloured to a coloured state. It will therefore be appreciated that upon application of the NIR or IR radiation, the deactivation temperature will also be reached and the deactivatable component will be‘deactivated’ at the localised positions, such that it is not capable of undergoing any subsequent transitions.

UV radiation is then applied to the substrate by flood illumination using a 30W germicidal UV lamp for 20 seconds. The non-coloured state of the deactivatable component therefore transitions from the non-coloured to a first blue coloured state across the substrate except from those localised positions where the coloured state of the component of (VIII) has been formed and the deactivatable component has been‘deactivated’. The first coloured state of the deactivatable component is blue in colour, and in combination with the pale yellow colour displayed by the non-coloured state of the compound of formula (VIII), the substrate displays a green colour where the first coloured state of the deactivatable component has been formed.

Alternatively, following application of the layers to the paper substrate, UV radiation by flood illumination using a 30W germicidal UV lamp for 30 seconds (applied transition stimulus) is applied to the substrate. Across the substrate, the non-coloured state of the deactivatable component transitions from the non- coloured to a first blue coloured state. It is noted that the compound of formula (VIII) does not transition as it is accompanied by a thermal acid-generating agent, and thus requires additional temperature to facilitate a transition from its non-coloured state to a coloured state. However, following the application of the applied transition stimulus to the substrate, IR radiation using a 10.6 pm C0 ₂ laser (2600-5350 mm/s, 38% power) or NIR radiation using a Nd:YAG 1064 nm NIR laser (50% speed, 20-80% power) is applied to localised positions of the substrate (additional temperature). At these localised positions, the compound of formula (VIII) transitions from its non-coloured state to a coloured state at these localised positions. The colour of the coloured state, and intensity thereof, can be made to vary between yellow or orange by variation of fluence, e.g. by varying the power of the C0 ₂ or NIR laser. It is noted that, as discussed above, the deactivation temperature of the deactivatable component is lower than the additional temperature required to facilitate a transition of the compound of formula (VIII) from the non-coloured to a coloured state. It will therefore be appreciated that upon application of the NIR or IR radiation, the deactivation temperature will also be reached and the deactivatable component transitions from the first blue coloured state to a red second coloured state. The red deactivatable component is deactivated at these localised positions and will not undergo any subsequent transition. The intensity of the coloured state can be made to vary by variation of the fluence. As the second coloured state of the deactivatable component is formed at the same localised position at which the coloured state of the compound of formula (VIII) has been formed, the final colour displayed at these localised positions is dependent upon the colour of the coloured state of the compound of formula (VIII), and the colour of the second red coloured state of the deactivatable component, i.e. the final colour at these localised positions results from the combination of colours of the coloured states of these two components. Accordingly, orange and red colours may be formed.

A multi-coloured image displaying blue, yellow, orange, green and red colours may therefore be formed.

Example 8

A composition comprising a deactivatable component and a compound of formula (VIII) formed from a salicylic aldehyde or salicylic ketone compound and an acid-generating agent is formulated by combing 1 part of the formulation of Table 15 above, using the millbase formulations of Tables 13 and 14 (the deactivatable component having been replaced by di-tert-butyl 2,2’-(tetradeca- 6,8-diynedioyl)bis(hydrazine-1 ,20 carboxylate)), with 1 part of a 50:50 mixture of the formulations of Tables 16 and 17 above. A layer of the composition was applied onto a paper substrate (folding carton) using a 20 pm k-bar applicator.

Following application of the layer to the paper substrate, the deactivatable component and the compound of formula (VIII) are in their non-coloured states. The natural state (non-coloured state) of the compound of formula (VIII) is a pale yellow, and therefore the PET substrate displays this colour.

Upon application of IR radiation using a 10.6 pm C0 ₂ laser (2600-5350 mm/s, 38%, power) to localised positions of the substrate (additional temperature), the compound of formula (VIII) transitions from its non-coloured state to a coloured state at these localised positions. The colour of the coloured state, and intensity thereof, of the compound of formula (VIII) can be made to vary between yellow or orange by variation of the fluence applied by the laser, e.g. by varying the power of the C0 ₂ or NIR laser. It is noted that the deactivation temperature of the deactivatable component is lower than the additional temperature required to facilitate a transition of the compound of formula (VIII) from the non-coloured to a coloured state. It will therefore be appreciated that upon application of the IR radiation, the deactivation temperature will also be reached and the deactivatable component will be‘deactivated’ at the localised positions, such that it is not capable of undergoing any subsequent transitions.

UV radiation is then applied to the substrate by flood illumination using a germicidal UV lamp (applied transition stimulus). The non-coloured state of the deactivatable component therefore transitions from the non-coloured to a first red coloured state across the substrate except from those localised positions where the coloured state of the compound of formula (VIII) has been formed and the non-coloured state of the deactivatable component has been‘deactivated’.

Alternatively, following application of the layers to the paper substrate, UV radiation by flood illumination using a germicidal UV lamp (applied transition stimulus) is applied to the substrate. Across the substrate, the non-coloured state of the deactivatable component transitions from the non-coloured to a first red coloured state. It is noted that the compound of formula (VIII) does not transition as it is accompanied by a thermal acid-generating agent, and thus requires an additional temperature to facilitate a transition from its non-coloured state to a coloured state. However, following the application of the applied transition stimulus to the substrate, IR radiation using a 10.6 pm C0 ₂ laser (2600-5350 mm/s, 38% power) is applied to localised positions of the substrate (additional temperature, and deactivation temperature). At these localised positions, the compound of formula (VIII) transitions from its non-coloured state to a coloured state. The colour of the coloured state, and intensity thereof, can be made to vary between yellow or orange by variation of fluence, e.g. by varying the power of the C0 ₂ laser. It is noted that, as discussed above, the deactivation temperature of the deactivatable component is lower than the additional temperature required to facilitate a transition of the compound of formula (VIII) from the non-coloured to a coloured state. It will therefore be appreciated that upon application of the IR radiation, the deactivation temperature will also be reached and the deactivatable component transitions from the first red coloured state to a second yellow coloured state. The deactivatable component is deactivated at these localised positions. The intensity of the coloured state can be made to vary by variation of the fluence. As the second coloured state of the deactivatable component is formed at the same localised position at which the coloured state of the compound of formula (VIII) has been formed, the final colour displayed at these localised positions is dependent upon the initial colour formed by the coloured state of the compound of formula (VIII), and the colour of the second coloured state of the deactivatable component, i.e. the final colour at these localised positions results from the combination of colours of the coloured states of these two components. Accordingly, yellow and orange colours may be formed.

A multi-coloured image displaying different red, yellow and orange colours can therefore be formed.

Example 9 A composition comprising a deactivatable component and a pyrazole (thio)semicarbazone compound of formula (III) was formulated by combining a 50:50 mixture of the formulation of Table 15 above, using the millbase formulations of Tables 13 and 14, and Table 20. All amounts are provided in weight percentages (wt%).

Table 20

A layer of the composition was applied onto a paper substrate (craft paper) using a k2 k-bar applicator.

Following application of the composition to the paper substrate, the deactivatable component and the compound of formula (III) are in their non- coloured states.

Upon application of IR radiation to localised positions of the substrate using a 10.6 pm C0 ₂ laser (3000-5350 mm/s, 38-80% power) (deactivation temperature), the deactivatable component is‘deactivated’ and these localised positions such that it remains in the non-coloured state and will not undergo any subsequent transitions. Following application of UV radiation by flood illumination (applied transition stimulus) using a germicidal lamp, the deactivatable component transitions from the non-coloured state to a first blue coloured state across the substrate, apart from at those localised positions at which the deactivatable component has been‘deactivated’. In addition, the UV radiation acts as an additional applied stimulus such that the non-coloured state of the compound of formula (III) transitions to a pale yellow coloured state across the substrate. As the colour displayed by the substrate, except at those positions at which the non-coloured state of the deactivatable component has been deactivated, is a combination of the blue first coloured state of the deactivatable component and the pale yellow coloured state of the compound of formula (III), a blue colour is displayed. However, at the localised positons at which the deactivatable component has been deactivated, the pale yellow colour of the coloured state of the compound of formula (III) can be seen.

Alternatively, following application of the composition to the substrate, UV radiation by flood illumination using a germicidal lamp (applied transition stimulus) can be applied to the substrate such that the deactivatable component transitions from the non-coloured state to the first blue coloured state across the substrate. The compound of formula (III) also transitions from the non-coloured state to a pale yellow coloured state upon application of the UV radiation (additional applied stimulus) across the substrate. However, as the colour displayed by the substrate is a combination of the blue first coloured state of the deactivatable component and the pale yellow coloured state of the compound of formula (III), a blue colour is displayed.

Following application of the UV radiation, IR radiation is applied at localised positions using a 10.6 pm C0 ₂ laser (3000-5350 mm/s, 38-80% power) (deactivation temperature) and the first blue coloured state of the deactivatable component transitions to a second red coloured state at these localised positions.

A multi-coloured image displaying blue, yellow and red colours can therefore be formed. Example 10

A composition comprising an oxyanion of a multivalent metal was formulated according to Table 21. All amounts are provided in weight percentage (wt%).

Table 21

A composition comprising a leuco dye was formulated according to Table 22. All amounts are provided in weight percentage (wt%). Table 22

Table 23

A composition comprising a deactivatable component was formulated according to Table 15, using the millbase formulations of Tables 13 and 14 replacing the deactivatable component with di-tert-butyl-2,2’-(tetradeca-6,8- diynedioyl)bis(hydrazine-1 ,20-carboxylate).

A layer of the composition comprising the oxyanion of a multivalent metal was applied to a paper substrate using a k2 k-bar applicator. A layer of the composition comprising the leuco dye was then applied using a k2 k-bar applicator over the layer of the composition comprising the oxyanion of a multivalent metal. A layer of the composition comprising the deactivatable component was then applied using a k2 k-bar applicator over the layer of the composition comprising the leuco dye. Following application of the layers to the paper substrate, the deactivatable component, the leuco dye and the oxyanion of a multivalent metal are in their non-coloured states.

Upon application of IR radiation using a 10.6 pm C0 ₂ laser (38% power) to localised positions of the substrate (additional temperature), the oxyanion of a multivalent metal transitions from its non-coloured state to a coloured state at these localised positions. The colour of the coloured state of the oxyanion of a multivalent metal is black, the intensity of which can be altered by variation of fluence. In addition, the leuco dye also transitions from its non-coloured to a blue coloured state at these localised positions, the additional temperature for this component being very similar to the additional temperature required to effect the transition of the oxyanion of a multivalent metal. The intensity of the blue colour formed can be altered by varying the fluence applied by the laser. It is further noted that the deactivation temperature of the deactivatable component is lower than the additional temperature required to facilitate a transition of the oxyanion of a multivalent metal from the non-coloured to a coloured state. It will therefore be appreciated that upon application of the IR radiation, the deactivation temperature will also be reached and the deactivatable component will be ‘deactivated’ at the localised positions, such that it is not capable of undergoing any subsequent transitions. The final colour displayed at the localised positions is a combination of the blue colour of the coloured state of the leuco dye and the black colour of the coloured state of the oxyanion of a multivalent metal. Accordingly, different black and blue colours can be formed.

UV radiation is then applied to the substrate by flood illumination using a germicidal UV lamp (applied transition stimulus). The non-coloured state of the deactivatable component therefore transitions from the non-coloured to a first red coloured state across the substrate except from those localised positions where the coloured state of the oxyanion of a multivalent metal has been formed and the deactivatable component has been‘deactivated’.

Alternatively, following application of the layers to the paper substrate, UV radiation by flood illumination using a germicidal UV lamp (applied transition stimulus) is applied to the substrate. Across the substrate, the non-coloured state of the deactivatable component transitions to a first red coloured state. It is noted that the oxyanion of anion of a multivalent metal and leuco dye do not transition as they require an additional temperature to facilitate a transition from the non-coloured state to a coloured state.

Following the application of the UV radiation to the substrate, IR radiation using a 10.6 pm C0 ₂ laser (10-20% power) is applied to localised positions of the substrate (deactivation temperature). At these localised positions, the deactivatable component transitions from the first red coloured state to a yellow second coloured state. The deactivatable component is deactivated at these localised positions and will not undergo any subsequent transition. The intensity of the coloured state can be made to vary by variation of the fluence. However, the 10-20% power of the C0 ₂ laser means that the temperature applied to the localised positions is not high enough to facilitate a transition of the oxyanion of a multivalent metal or leuco dye as the additional temperatures for transition of the oxyanion of a multivalent metal and leuco dye are higher than the deactivation temperature for the deactivatable component. The coloured state of the oxyanion of a multivalent metal or leuco dye is therefore not formed at these positions. However, if the power of the 10.6 pm C0 ₂ laser is increased to 38%, the deactivatable component transitions from the red first coloured state to the yellow second coloured state, and the oxyanion of a multivalent metal and leuco dye also transitions from a non-coloured to a black coloured state and blue coloured state respectively. The intensity of the black colour of the coloured state of the oxyanion of a multivalent metal and the blue colour of the coloured state of the leuco dye can be varied by alteration of the fluence of the C0 ₂ laser. As the second yellow coloured state of the deactivatable component is formed at the same localised position at which the black coloured state of the oxyanion of a multivalent metal and the blue coloured state of the leuco dye are formed, the final colour displayed at these localised positions is dependent upon the black colour of the coloured state of the oxyanion of the multivalent metal, the blue colour of the coloured state of the leuco dye and the yellow colour of the second coloured state of the deactivatable component, i.e. the final colour at these localised positions results from the combination of colours of the coloured states of these two components. Accordingly, black-yellow, black-blue and black colours may be formed.

A multi-coloured image displaying yellow, black, red, blue, black-yellow and black-blue colours can therefore be formed.

Example 1 1

A composition comprising a deactivatable component and a pyrazole (thio)semicarbazone compound of formula (III) was formulated using 1 part of the formulation according to Table 15 above, using the millbase formulations of Tables 13 and 14, and 1 part of the formulation according to Table 20 above. A layer of the composition was applied to a paper substrate using a k2 k-bar applicator.

Following application of the composition to the paper substrate, the deactivatable component and compound of formula (III) are in their non-coloured states.

Upon application of IR radiation using a 10.6 pm C0 ₂ laser (20% power) to localised positions of the substrate (deactivation temperature), the deactivatable component will be‘deactivated’ at those localised positions, such that it is not capable of undergoing any subsequent transitions.

UV radiation is then applied to the substrate by flood illumination using a germicidal UV lamp (applied transition stimulus). The non-coloured state of the deactivatable component therefore transitions from the non-coloured to a first blue coloured state across the substrate except from those localised positions where the non-coloured state of the deactivatable component has been ‘deactivated’. In addition, upon application of the UV radiation, the compound of formula (III) transitions from the non-coloured to a yellow coloured state across the substrate. At the localised positions at which the deactivatable component has been deactivated, solely the yellow colour of the coloured state of the compound of formula (III) is displayed. For the rest of the substrate, the colour displayed is a combination of the yellow colour of the coloured state of the compound of formula (VIII) and the blue colour of the first coloured state of the deactivatable component. Accordingly, other than at the localised positions discussed above, the substrate displays a turquoise colour. An increased length of application of the UV radiation provides a more intense turquoise colour.

A multi-coloured image displaying yellow and turquoise colours can therefore be formed.

Example 12 A composition comprising an oxyanion of a multivalent metal was formulated according to Table 21 above.

A composition comprising a deactivatable component was formulated according to Table 15, using the millbase formulations or Tables 13 and 14, but replacing the deactivatable component with di-tert-butyl-2,2’-(tetradeca-6,8- diynedioyl)bis(hydrazine-1 ,20-carboxylate).

A layer of the composition comprising the oxyanion of a multivalent metal was applied to a paper substrate using a k2 k-bar applicator. A layer of the composition comprising the deactivatable component was then applied using a k2 k-bar applicator over the layer of the composition comprising the oxyanion of a multivalent metal.

Following application of the layers to the paper substrate, the deactivatable component and the oxyanion of a multivalent metal are in their non-coloured states.

Upon application of IR radiation using a 10.6 pm C0 ₂ laser (10% power) to localised positions of the substrate (deactivation temperature), the deactivatable component is‘deactivated’ at the localised positions, such that it is not capable of undergoing any subsequent transitions. It is noted that the temperature required for the additional temperature to facilitate a transition of the oxyanion of a multivalent metal is higher than the deactivation temperature. The temperature applied by the 10% power C0 ₂ laser is thus not great enough to facilitate such a transition, and the oxyanion of a multivalent metal remains in its non-coloured state and these localised positions.

UV radiation is then applied to the substrate by flood illumination using a germicidal UV lamp (applied transition stimulus). The non-coloured state of the deactivatable component therefore transitions from the non-coloured to a first red coloured state across the substrate except from those localised positions where the non-coloured state of the deactivatable component has been ‘deactivated’. Alternatively, following application of the layers to the paper substrate, IR radiation using a 10.6 pm C0 ₂ laser (38% power) is applied to localised positions of the substrate (deactivation temperature, and additional temperature). At these localised positions, not only is the deactivatable component ‘deactivated’ such that it is not capable of undergoing any subsequent transitions, but the transition of the oxyanion of a multivalent metal is facilitated as the 38% power provides the higher temperature required for the additional temperature. The coloured state of the oxyanion of a multivalent metal formed is black, and the intensity of the colour can be altered by variation of the fluence of the C0 ₂ laser. UV radiation is then applied to the substrate by flood illumination using a germicidal UV lamp (applied transition stimulus). The non-coloured state of the deactivatable component therefore transitions from the non-coloured to a first red coloured state across the substrate except from those localised positions where the coloured state of the oxyanion of a multivalent metal has been formed and the deactivatable component has been‘deactivated’.

Alternatively, following application of the layers to the paper substrate, UV radiation by flood illumination using a germicidal UV lamp (applied transition stimulus) is applied to the substrate. Across the substrate, the non-coloured state of the deactivatable component transitions from the non-coloured to a first red coloured state. Following the application of the applied transition stimulus to the substrate, IR radiation using a 10.6 pm C0 ₂ laser (10% power) is applied to localised positions of the substrate (deactivation temperature). At these localised positions, the deactivatable component transitions from the first red coloured state to a yellow second coloured state. The deactivatable component is deactivated at these localised positions and does not undergo any subsequent transition. The intensity of the coloured state can be made to vary by variation of the fluence. However, as discussed above, the 10% power of the C0 ₂ laser means that the temperature applied to the localised positions is not high enough to facilitate a transition of the oxyanion of a multivalent metal as the additional temperature required to effect the transition of the oxyanion of a multivalent metal is higher than the deactivation temperature for the deactivatable component. The coloured state of the oxyanion of a multivalent metal is therefore not formed at these positions. However, if the power of the 10.6 pm C0 ₂ laser is increased to 20%, the deactivatable component transitions from the red first coloured state to the yellow second coloured state, and the oxyanion of a multivalent metal also transitions from a non-coloured to a black coloured state. The intensity of the colour of the coloured state can be varied by alteration of the fluence of the C0 ₂ laser. If the transition from the non-coloured state to the coloured state of the oxyanion of a multivalent metal is facilitated, as the second coloured state of the deactivatable component is formed at the same localised position at which the coloured state of the oxyanion of a multivalent metal is formed, the final colour displayed at these localised positions is dependent upon the initial colour formed by the coloured state of the oxyanion of the multivalent metal, and the colour of the second coloured state of the deactivatable component, i.e. the final colour at these localised positions results from the combination of colours of the coloured states of these two components. Accordingly, yellow, brown and black colours can be formed.

A multi-coloured image can therefore be formed having black, brown, red and yellow colours. In addition, the non-coloured state of the diacetylene component can form part of the multi-coloured image.

Example 13

A composition comprising an oxyanion of a multivalent metal was formulated according to Table 21 above.

A composition comprising a compound of formula (VIII) formed from a salicylic aldehyde or salicylic ketone compound and acid-generating agent was formulated according to a 50:50 mixture of the formulations of Tables 16 and 17.

A composition comprising a deactivatable component was formulated according to T able 15 above, using the millbase formulations of T ables 13 and 14.

A layer of the composition comprising the oxyanion of a multivalent metal was applied to a paper substrate using a k2 k-bar applicator. A layer of the composition comprising the compound of formula (VIII) and acid-generating agent was applied using a k2 k-bar applicator over the layer of the composition comprising the oxyanion of a multivalent metal. A layer of the composition comprising the deactivatable component was then applied using a k2 k-bar applicator over the layer of the composition comprising the compound of formula (VIII) and acid-generating agent.

Following application of the layers to the paper substrate, the deactivatable component, the oxyanion of a multivalent metal and the compound of formula (VIII) are in their non-coloured states. The natural state (non-coloured state) of the compound of formula (VIII) is pale yellow and therefore, the substrate displays this colour.

Upon application of IR radiation using a 10.6 pm C0 ₂ laser (20% power) to localised positions of the substrate (additional temperature), the non-coloured state of the compound of formula (VIII) transitions from the pale yellow non- coloured to a coloured state. The colour of the coloured state, and intensity thereof, can be made to vary between yellow or orange by variation of the fluence applied by the laser. It is noted that the deactivation temperature is lower than the additional temperature required to facilitate a transition of the compound of formula (VIII) from the non-coloured to a coloured state. Therefore, it will be appreciated that upon application of the IR radiation for the additional temperature, the deactivation temperature is also reached and the deactivatable component will be‘deactivated’ at those localised positions, such that it is not capable of undergoing any subsequent transitions and remains in the non-coloured state at these localised positions. It is noted that the application of IR radiation using a C0 ₂ laser at 10% power does not apply a temperature high enough to facilitate a transition of the oxyanion of a multivalent metal from the non-coloured state to a coloured state. This is on account of the fact that the additional temperature of the oxyanion of a multivalent metal is higher than the additional temperature required for the compound of formula (VIII) to transition, and the deactivation temperature of the deactivatable component. However, if the power of the laser is increased to 38% power, the additional temperature for the oxyanion of a multivalent metal is reached and the oxyanion of a multivalent metal transitions from the non-coloured to a black coloured state. The intensity of the black coloured state can be made to vary by variation of fluence. As the coloured state of the compound of formula (VIII) is formed at the same localised position at which the coloured state of the oxyanion of a multivalent metal is formed, the final colour displayed at these localised positions is dependent upon the black colour of the coloured state of the oxyanion of the multivalent metal, and the colour of the coloured state of the compound of formula (VIII), i.e. the final colour at these localised positions results from the combination of colours of the coloured states of these two components. Accordingly, black, brown and yellow colours can be formed.

UV radiation is then applied to the substrate by flood illumination using a germicidal UV lamp (applied transition stimulus). The non-coloured state of the deactivatable component therefore transitions from the non-coloured to a first blue coloured state across the substrate except from those localised positions where the non-coloured state of the deactivatable component has been ‘deactivated’. It will be appreciated that the colour displayed is a combination of the pale yellow colour displayed by the non-coloured state of the compound of formula (VIII) and the blue colour of the first coloured state of the deactivatable component. Accordingly, other than at the localised positions discussed above, the substrate displays a turquoise colour. An increased length of application of the UV radiation provides a more intense turquoise colour.

Alternatively, following application of the layers to the paper substrate, UV radiation by flood illumination using a germicidal UV lamp (applied transition stimulus) is applied to the substrate. Across the substrate, the non-coloured state of the deactivatable component transitions from the non-coloured to a first blue coloured state. It will be appreciated that the colour displayed is a combination of the pale yellow colour displayed by the non-coloured state of the compound of formula (VIII) and the blue colour of the first coloured state of the deactivatable component. Accordingly, other than at the localised positions discussed above, the substrate displays a turquoise colour. An increased length of application of the UV radiation provides a more intense turquoise colour.

IR radiation is then applied using a 10.6 pm C0 ₂ laser (20% power) to localised positions of the substrate (additional temperature), as discussed above the non- coloured state of the compound of formula (VIII) transitions from the pale yellow non-coloured to a coloured state. The colour of the coloured state, and intensity thereof, can be made to vary between yellow or orange by variation of fluence. As discussed above, the deactivation temperature is lower than the additional temperature required to facilitate a transition of the compound of formula (VIII) from the non-coloured to a coloured state. Therefore, upon application of the IR radiation, the deactivation temperature is reached and the first blue coloured state of the deactivatable component transitions to a second red coloured state. As the second red coloured state of the deactivatable component is formed at the same localised position at which the coloured state of the compound of formula (VIII) is formed, the final colour displayed at these localised positions is dependent upon the colour of the coloured state of the compound of formula (VIII), and the second red coloured state of the deactivatable component, i.e. the final colour at these localised positions results from the combination of colours of the coloured states of these two components. Accordingly, orange and brown colours can be formed.

It is noted that the application of IR radiation using a C0 ₂ laser at 20% power does not apply a temperature high enough to facilitate a transition of the oxyanion of a multivalent metal from the non-coloured state to a coloured state. This is on account of the fact that the additional temperature of the oxyanion of a multivalent metal is higher than the additional temperature required for the compound of formula (VIII) to transition, and the deactivation temperature of the deactivatable component. However, if the power of the laser is increased to 38% power, the additional temperature for the oxyanion of a multivalent metal is also reached and the oxyanion of a multivalent metal transitions from the non- coloured to a black coloured state. The intensity of the black coloured state can be made to vary by variation of the fluence applied by the laser. As the black coloured state of the oxyanion of a multivalent metal is formed at the same localised position at which the coloured state of the deactivatable component and the compound of formula (VIII) is formed, the final colour displayed at these localised positions is dependent upon the black colour of the coloured state of the oxyanion of the multivalent metal, and the red second coloured state of the deactivatable component and the compound of formula (VIII), i.e. the final colour at these localised positions results from the combination of colours of the coloured states of these two components. Accordingly, black and orange colours can be formed.

A multi-coloured image displaying yellow, orange, red, black, brown and turquoise can therefore be formed.

Example 14

A composition comprising an oxyanion of a multivalent metal was formulated according to Table 21 above.

A composition comprising a deactivatable component and a pyrazole (thio)semicarbazone compound of formula (III) formulated according to 1 part of the formulation of Table 15 above, using the millbase formulations of Tables 13 and 14, and 1 part of the formation of Table 20 above.

A layer of the composition comprising the oxyanion of a multivalent metal was applied to a paper substrate using a k2 k-bar applicator. A layer of the composition comprising the deactivatable component and the compound of formula (III) was applied using a k2 k-bar applicator over the layer of the composition comprising the oxyanion of a multivalent metal.

Following application of the layers to the paper substrate, the deactivatable component, the oxyanion of a multivalent metal and the compound of formula (III) are in their non-coloured states.

Upon application of IR radiation using a 10.6 pm C0 ₂ laser (20% power) to localised positions of the substrate (deactivation temperature), the deactivatable component is‘deactivated’ in its non-coloured state at the localised positions, such that it is not capable of undergoing any subsequent transitions. It is noted that the temperature required for the additional temperature to facilitate a transition of the oxyanion of a multivalent is higher than the deactivation temperature. The temperature applied by the 20% power C0 ₂ laser is thus not great enough to facilitate such transitions, and the oxyanion of a multivalent metal remains in its non-coloured state at these localised positions. However, if the power of the laser is increased to 38% power, the additional temperature is reached and the oxyanion of a multivalent metal transitions from the non- coloured to a black coloured state. The intensity of the black coloured state can be made to vary by variation of fluence.

UV radiation is then applied to the substrate by flood illumination using a germicidal UV lamp (applied transition stimulus). The non-coloured state of the deactivatable component therefore transitions from the non-coloured to a first blue coloured state across the substrate except from those localised positions where the deactivatable component has been ‘deactivated’, and the coloured state of the oxyanion of a multivalent metal optionally formed. An increased length of application of the UV radiation provides a more intense colour. The UV radiation also acts as the additional applied stimulus and the compound of formula (III) also transitions from the non-coloured to a pale yellow coloured state across the substrate. The pale yellow colour can be seen at the localised positions at which the deactivatable component has been deactivated.

Alternatively, following application of the layers to the paper substrate, UV radiation by flood illumination using a germicidal UV lamp (applied transition stimulus) is applied to the substrate. Across the substrate, the non-coloured state of the deactivatable component transitions from the non-coloured to a first blue coloured state. An increased length of application of the UV radiation provides a more intense colour. The UV radiation also acts as the additional applied stimulus and the compound of formula (I) transitions from the non- coloured to a pale yellow coloured state across the substrate. As the colour displayed across the substrate is a combination of the pale yellow coloured state of the compound of formula (III) and the blue colour of the coloured state of the deactivatable component, the colour displayed across the substrate is blue.

IR radiation is then applied using a 10.6 pm C0 ₂ laser (20% power) to localised positions of the substrate (deactivation temperature), and the deactivatable component transitions from its blue first coloured state to its red second coloured state at these localised positions. The intensity of the colour of the second coloured state can be made to vary by altering the fluence applied by the C0 ₂ laser. As discussed above, the temperature applied by the 20% power C0 ₂ laser is not great enough to facilitate the transition of the oxyanion of a multivalent metal from the non-coloured to a coloured state, and the oxyanion of a multivalent metal remains in its non-coloured state at these localised positions. However, if the power of the laser is increased to 38% power, the additional temperature for the oxyanion of a multivalent metal is reached and the oxyanion of a multivalent metal also transitions from the non-coloured to a black coloured state. The intensity of the black coloured state can be made to vary by variation of fluence. As the second coloured state of the deactivatable component is formed at the same localised position at which the coloured state of the oxyanion of a multivalent metal is formed, the final colour displayed at these localised positions is dependent upon the black colour of the coloured state of the oxyanion of the multivalent metal, and the red second coloured state of the deactivatable component, i.e. the final colour at these localised positions results from the combination of colours of the coloured states of these two components. Accordingly, black and brown colours may be formed.

A multi-coloured image displaying black, orange, red, brown and blue colours can be formed. In addition, the non-coloured state of the deactivatable component can form part of the multi-coloured image.

Example 15

A composition comprising an oxyanion of a multivalent metal was formulated according to Table 21 above.

A composition comprising a compound of formula (VIII) and a base-generating agent is formed from a salicylic aldehyde or salicylic ketone compound was formulated according to a 50:50 mixture of the formulations of Tables 18 and 19 above.

A composition comprising a deactivatable component was formulated according to T able 15 above, using the millbase formulations of T ables 13 and 14.

A layer of the composition comprising an oxyanion of a multivalent metal was applied to a paper substrate using a k2 k-bar applicator. A layer of the composition comprising a compound of formula (VIII) was then applied using a k2 k-bar applicator over the layer of the composition comprising an oxyanion of a multivalent metal. A layer of the composition comprising deactivatable component was then applied using a k2 k-bar applicator over the layer of the composition comprising a compound of formula (VIII).

Following application of the layers to the substrate, UV radiation (applied transition stimulus) was applied by flood illumination using a germicidal lamp. The deactivatable component transitions from the non-coloured state to a first coloured state across the substrate, such that a blue colour is displayed across the substrate. Upon application of IR radiation using a 10.6 pm C0 ₂ laser (20% power) at localised positions (deactivation temperature), this first blue coloured state transitions to a second red coloured state. The deactivatable component is deactivated at these localised positions and incapable of undergoing any subsequent transitions. The intensity of the red second coloured state formed can be varied by altering the fluence applied by the laser. In addition, upon application of the IR radiation, the additional temperature for the compound of formula (VIII) is also reached (the additional temperature is slightly lower than the deactivation temperature in this case) and the compound of formula (VIII) transitions from the non-coloured state to a yellow coloured state at the localised positions. It will be appreciated that the intensity of this coloured state can be varied by altering the fluence applied by the laser. As the coloured state of the compound of formula (VIII) is formed at the same localised position at which the second red coloured state of the deactivatable component has been formed, the final colour displayed at these localised positions is dependent upon the red second coloured state of the deactivatable component, and the yellow coloured state of the compound of formula (VIII), i.e. the final colour at these localised positions results from the combination of colours of the coloured states of the two components. Accordingly, different orange colours can be formed.

It is noted that the application of the IR radiation using a 10.6 pm C0 ₂ laser at 20% does not provide an additional temperature high enough to facilitate a transition of the oxyanion of a multivalent metal from its non-coloured state to a coloured state. This is on account of the fact that the additional temperature required for the transition of the oxyanion of a multivalent metal to be effected is higher than the additional temperature required for the transition of the compound of formula (VIII) to be effected, and the deactivation temperature of the deactivatable component. Accordingly, when IR radiation is applied using a 10.6 pm C0 ₂ laser at 38% power, i.e. increased power, the additional temperature for the oxyanion of a multivalent metal is reached and the oxyanion of a multivalent metal transitions from the non-coloured to a black coloured state. The intensity of this black coloured state can be varied by alteration of the applied fluence. If the coloured state of the oxyanion of a multivalent metal is formed, as the coloured state will be formed at the same localised position at which the second red coloured state of the deactivatable component and the yellow or orange coloured state of the compound of formula (VIII) has been formed, the final colour displayed at these localised positions is dependent upon the colour of the red second coloured state of the deactivatable component, the yellow or orange colour of the coloured state of the compound of formula (VIII) and the black coloured state of the oxyanion of a multivalent metal i.e. the final colour at these localised positions results from the combination of colours of the coloured states of the three components. Accordingly, different orange, brown and black colours can be formed.

Alternatively, following application of the layers to the substrate, IR radiation is applied to the substrate using a 10.6 pm C0 ₂ laser (38% power) (additional temperature). As discussed above, given the power of the C0 ₂ laser, a transition from the non-coloured to a black coloured state of the oxyanion of a multivalent metal is effected. The intensity of the coloured state formed can be varied by altering the applied fluence. As the additional temperature required to facilitate the transition of the oxyanion of a multivalent metal is greater than the additional temperature required for the transition of the compound of formula (VIII) from the non-coloured to a coloured state, the transition of the compound of formula (VIII) to a yellow coloured state is also effected upon application of the IR radiation. If the C0 ₂ laser is utilised at a lower power, as discussed above, only the compound of formula (VIII) will transition to a coloured state and a yellow colour is displayed at those localised positions on the substrate.

A multi-coloured image displaying black, yellow, blue, orange, brown and black colours can therefore be formed. Example 16

A composition comprising a keto acid compound of formula (V) and an acid- generating agent is formulated according to Table 24. All amounts are provided in weight percentage (wt%). Table 24

A composition comprising a deactivatable component is formulated according to Table 15 above, using the millbase formulations of Tables 13 and 14.

A layer of the composition comprising a keto acid compound of formula (V) and an acid-generating agent is applied to a paper substrate using a k2 k-bar applicator. A layer of the composition comprising a deactivatable component is applied using a k2 k-bar applicator over the layer of the composition comprising a compound of formula (V) and an acid-generating agent. Upon application to the substrate, the deactivatable component and the compound of formula (V) are in their non-coloured states. The non-coloured state of the keto acid compound of formula (V) is pale yellow, and therefore the paper substrate displays this colour.

Upon application of IR radiation using a 10.6 pm C0 ₂ laser (20%) (deactivation temperature) at localised positions of the substrate, the deactivatable component is‘deactivated’ and will remain in the non-coloured state, i.e. not be capable of undergoing any subsequent transitions. It is noted that the deactivation temperature is lower than the additional temperature required to facilitate a transition of the keto acid compound of formula (V) from the non-coloured to a yellow coloured state. Therefore, upon application of the IR radiation with the laser only a 20% power, the transition of the keto acid compound of formula (V) does not occur. However, if the power of the C0 ₂ laser is increased to 38%, the keto acid compound of formula (V) transitions from the non-coloured state to a yellow coloured state. The intensity of the colour of the formed coloured state can be varied by variation of the fluence, e.g. by varying the power of the C0 ₂ laser.

Following application of UV radiation by flood illumination using a germicidal lamp (applied transition stimulus), the deactivatable component transitions from the non-coloured state to a blue first coloured state across the substrate, apart from at those localised positions at which the non-coloured state of the deactivatable component has been deactivated. If the transition of the keto acid compound of formula (V) was not facilitated by the previous IR radiation, the localised positions display the non-coloured state of the deactivatable component. If the transition of the keto acid compound of formula (V) was facilitated by the IR radiation, the localised positions display the yellow coloured state of the keto acid compound of formula (V).

Alternatively, following application of the layers to the substrate, if UV radiation is applied by flood illumination using a germicidal lamp to the substrate (applied transition stimulus), the deactivatable component transitions from the non- coloured state to a blue first coloured state across the substrate. Following subsequent application of IR radiation at localised positions of the substrate using a 10.6 pm C0 ₂ laser (20% power) (deactivation temperature), the first blue coloured state transitions to a red second coloured state at those localised positions. The deactivation component is deactivated at these localised positions and will not undergo any further transitions. The intensity of the colour of the red second coloured state can be made to vary by altering the fluence applied by the laser. As discussed above, the keto acid compound of formula (V) does not also transition to a coloured state as the additional temperature required is greater than the deactivation temperature. However, if the power of the C0 ₂ laser is increased to 38%, the keto acid compound of formula (V) also transitions at the localised positions from the non-coloured to a yellow coloured state. The intensity of the colour of the coloured state can be made to vary by altering the fluence applied by the laser. As both the yellow coloured state of the keto acid compound of formula (V) and the red second coloured state of the deactivatable component are formed at the same localised positions on the substrate, the colour displayed is a combination of these colours. Accordingly, different orange colours can be formed.

A multi-coloured image displaying blue, yellow and orange colours can therefore be formed. In addition, the non-coloured state of the deactivatable component can form part of the multi-coloured image.

Example 17

A composition comprising a keto acid compound of formula (V) and an acid- generating was formulated according to Table 24, the keto acid compound of formula (V) being replaced by (2,3,4,5-tetrachloro-6-(4-(diethylamino)-2- hydroxybenzoyl)benzoic acid.

A composition comprising a deactivatable component was formulated according to T able 15 above, using the millbase formulations of T ables 13 and 14.

A layer of the composition comprising a keto acid compound of formula (V) was applied to a paper substrate using a k2 k-bar applicator. A layer of the composition comprising a deactivatable component was applied using a k2 k-bar applicator over the layer of the composition comprising a keto acid compound of formula (V).

Following application of the layers to the substrate, the deactivatable component and the compound of formula (V) are in their non-coloured states.

Upon application of IR radiation using a 10.6 pm C0 ₂ laser (20%) (deactivation temperature) at localised positions of the substrate, the deactivatable component is‘deactivated’ and will remain in the non-coloured state, i.e. not be capable of undergoing any subsequent transitions. It is noted that the deactivation temperature is lower than the additional temperature required to facilitate a transition of the keto acid compound of formula (V) from the non-coloured to a yellow coloured state. Therefore, upon application of the IR radiation with the laser only a 20% power, the transition of the keto acid compound of formula (V) does not occur. However, if the power of the C0 ₂ laser is increased to 38%, the keto acid compound of formula (V) transitions from the non-coloured state to a yellow coloured state. The intensity of the colour of the formed coloured state can be varied by variation of the fluence, e.g. by varying the power of the C0 ₂ laser.

Upon application of UV radiation by flood illumination using a germicidal lamp (applied transition stimulus), the non-coloured state of the deactivatable component transitions to a first blue coloured state across the substrate apart from those localised positions at which the deactivatable component has been ‘deactivated’. If the transition of the keto acid compound of formula (V) was not facilitated by the previous IR radiation, the localised positions display the non- coloured state of the deactivatable component. If the transition of the keto acid compound of formula (V) was facilitated by the IR radiation, the localised positions display the yellow coloured state of the keto acid compound of formula (V).

Alternatively, following application of the layers to the substrate, if UV radiation is applied by flood illumination using a germicidal lamp to the substrate (applied transition stimulus), the deactivatable component transitions from the non- coloured state to a blue first coloured state across the substrate. Following subsequent application of IR radiation at localised positions of the substrate using a 10.6 pm C0 ₂ laser (20% power) (deactivation temperature), the first blue coloured state transitions to a red second coloured state at those localised positions. The intensity of the colour of the red second coloured state can be made to vary by altering the fluence applied by the laser. As discussed above, the keto acid compound of formula (V) does not also transition to a coloured state as the additional temperature required is greater than the deactivation temperature. However, if the power of the C0 ₂ laser is increased to 38%, the keto acid compound of formula (V) also transitions at the localised positions from the non-coloured to a yellow coloured state. The intensity of the colour of the coloured state can be made to vary by altering the fluence applied by the laser. As both the yellow coloured state of the keto acid compound of formula (V) and the red second coloured state of the deactivatable component are formed at the same localised positions on the substrate, the colour displayed is a combination of these colours. Accordingly, different orange colours can be formed.

A multi-coloured image displaying blue, yellow and orange colours can therefore be formed. In addition, the non-coloured state of the deactivatable component can form part of the multi-coloured image.

Example 18

A composition comprising a keto acid compound of formula (V) and an acid- generating agent was formulated according to Table 24, the keto acid compound of formula (V) being replaced with (2-(4-(diethylamino)-2-hydroxybenzoyl)-5- nitrobenzoic acid.

A composition comprising a deactivatable component was formulated according to T able 15 above, using the millbase formulations of T ables 13 and 14.

A layer of the composition comprising a keto acid compound of formula (V) was applied to a paper substrate using a k2 k-bar applicator. A layer of the composition comprising a deactivatable component was then applied using a k2 k-bar applicator over the layer of the composition comprising a keto acid compound of formula (V). Following application of the layers to the substrate, the deactivatable component and the keto acid compound of formula (V) are in their non-coloured states. The non-coloured state of the keto acid compound of formula (V) is pale yellow, and therefore the paper substrate displays this colour.

Upon application of IR radiation using a 10.6 pm C0 ₂ laser (20%) (deactivation temperature) at localised positions of the substrate, the deactivatable component is‘deactivated’ and will remain in the non-coloured state, i.e. not be capable of undergoing any subsequent transitions. It is noted that the deactivation temperature is lower than the additional temperature required to facilitate a transition of the keto acid compound of formula (V) from the non-coloured to a coloured state. Therefore, upon application of the IR radiation with the laser only a 20% power, the transition of the keto acid compound of formula (V) does not occur. However, if the power of the C0 ₂ laser is increased to 38%, the keto acid compound of formula (V) transitions from the non-coloured state to a yellow coloured state. The colour of the coloured state, and intensity thereof can be made to vary between yellow and orange by altering the fluence applied by the laser.

Upon application of UV radiation by flood illumination using a germicidal lamp (applied transition stimulus), the non-coloured state of the deactivatable component transitions to a first blue coloured state across the substrate apart from those localised positions at which the deactivatable component has been ‘deactivated’. If the transition of the keto acid compound of formula (V) was not facilitated by the previous IR radiation, the localised positions display the non- coloured state of the deactivatable component. If the transition of the keto acid compound of formula (V) was facilitated by the IR radiation, the localised positions display the coloured state of the keto acid compound of formula (V).

Alternatively, following application of the layers to the substrate, if UV radiation is applied by flood illumination using a germicidal lamp to the substrate, the deactivatable component transitions from the non-coloured state to a blue first coloured state across the substrate. Following subsequent application of IR radiation at localised positions of the substrate using a 10.6 pm C0 ₂ laser (20% power) (deactivation temperature), the first blue coloured state transitions to a red second coloured state at those localised positions. The deactivatable component is deactivated. The intensity of the colour of the red second coloured state can be made to vary by altering the fluence applied by the laser. As discussed above, the keto acid compound of formula (V) does not also transition to a coloured state as the additional temperature required is greater than the deactivation temperature. However, if the power of the C0 ₂ laser is increased to 38%, the keto acid compound of formula (V) also transitions at the localised positions from the non-coloured to a yellow coloured state. The colour of the coloured state, and intensity thereof, can be made to vary between yellow or orange by altering the fluence applied by the laser. As both the coloured state of the keto acid compound of formula (V) and the red second coloured state of the deactivatable component are formed at the same localised positions on the substrate, the colour displayed is a combination of these colours. Accordingly, different red, brown and orange colours can be formed.

A multi-coloured image displaying blue, yellow, red, brown and orange colours can therefore be formed. In addition, the non-coloured state of the deactivatable component can form part of the multi-coloured image.

Example 19

A composition comprising a keto acid compound of formula (V) and an acid generating agent was formulated according to Table 24, the keto acid compound of formula (V) being replaced with (2,5-bis(4-(diethylamino)-2- hydroxybenzoyl)terephthalic acid.

A composition comprising a deactivatable component formulated according to Table 15, using the millbase formulations of Tables 13 and 14, the deactivatable component replaced by di-tert-butyl (((docosa-10,12- diynedioyl)bis)azanediyl))bis(ethane-1 ,2,diyl))dicarbamate.

A layer of the composition comprising a keto acid compound of formula (V) and an acid generating agent is applied to a paper substrate using a k2 k-bar applicator. A layer of the composition comprising a deactivatable component was applied using a k2 k-bar applicator over the layer of the composition comprising a keto acid compound of formula (V) and an acid-generating agent. Following application of the layers to the substrate, the keto acid compound of formula (V) and the deactivatable component are in their non-coloured states. The non-coloured state of the compound of formula (V) is yellow and therefore the substrate displays this colour.

Upon application of UV radiation using a germicidal lamp (applied transition stimulus), the non-coloured state of the deactivatable component transitions to a red first coloured state across the whole substrate. Following further application of IR radiation using a 10.6 pm C0 ₂ laser (38% power) (deactivation temperature) to localised positions of the substrate, the first red coloured state of the deactivatable component transitions to a blue second coloured state. The intensity of the colour of the second coloured state formed can be varied by altering the fluence of the C0 ₂ laser. It is noted that the deactivatable component is deactivated, and cannot undergo any subsequent transitions. It is further noted that the additional temperature required to facilitate a transition of the keto acid compound of formula (V) from the non-coloured to a coloured state is greater than the deactivation temperature. In this instance, the 38% power C0 ₂ laser provides a high enough temperature to reach the additional temperature and effect the transition of the keto acid compound of formula (V) from the non-coloured state to a coloured state. The colour of the coloured state, and intensity thereof, of the keto acid compound of formula (V) can be varied between yellow or orange by variation of fluence applied by the laser. As the coloured state of the compound of formula (V) is formed at the same localised position at which the second coloured state of the deactivatable component has been formed, the final colour displayed at these localised positions is dependent upon the blue colour of the second coloured state of the deactivatable component, and the colour of the coloured state of the compound of formula (V) that has been formed, i.e. the final colour at these localised positions results from the combination of colours of the coloured states of these two components. Accordingly, different orange, yellow and blue colours can be formed.

Upon further application of deactivation temperature by flood illumination using a heat gun, the deactivatable component transitions across the substrate from the first red coloured state to a blue second coloured state apart from at those localised positions at which the deactivatable component has already been deactivated. The deactivatable component remains unchanged at these localised positions, demonstrating that the deactivatable component will not undergo any further transitions. A multi-coloured image displaying yellow, orange, red and blue colours can be formed.

Example 20

A layer of a composition comprising a pyrazole (thio)semicarbazone compound of formula (III) and a base-generating agent was formulated according to a 2:1 blend of the formulations of Tables 25 and 26. All amounts are provided in weight percentage (wt%).

Table 25

Table 26

A composition comprising a deactivatable component was formulated according to Table 15, using the millbase formulations according to tables 13 and 14, the deactivatable component replaced by di-tert-butyl (((docosa-10,12- diynedioyl)bis)azanediyl))bis(ethane-1 ,2,diyl))dicarbamate.

A layer of the composition comprising a compound of formula (III) and a base- generating agent was applied to a paper substrate using a k2 k-bar applicator. A layer of the composition comprising a deactivatable component was then applied using a k2 k-bar applicator over the layer of the composition comprising a compound of formula (III) and a base-generating agent.

Following application of the layers to the substrate, UV radiation by flood illumination using a germicidal lamp was applied to the substrate (applied transition stimulus). The non-coloured state of the deactivatable component transitions to a first red coloured state across the substrate. It is noted that the transition of the compound of formula (III) from the non-coloured to a coloured state does not occur as a thermal acid-generating agent is utilised such that the additional temperature is required to facilitate the formation of colour with the compound of formula (III). Following application of IR radiation using a 10.6 pm C0 ₂ laser (38% power) to localised positions on the substrate (additional temperature), a transition from the non-coloured state to the coloured state of the compound of formula (III) is effected. The colour of the coloured state formed can be changed between yellow or orange, and the intensity thereof, by variation of the fluence of the C0 ₂ laser. It is noted that the deactivation temperature of the deactivatable component is lower than the additional temperature and therefore, upon application of the IR radiation, the deactivation temperature is reached and the deactivatable component transitions from the red first coloured state to a blue second coloured state at those positions. As the second blue coloured state of the deactivatable component is formed at the same localised positions as the coloured state of the compound of formula (III), the colour displayed at these localised positions is a combination of the colour of the coloured state of the compound of formula (III) and the second blue coloured state of the diacetylene compound. Accordingly, blue, yellow and orange colours can be formed.

Upon further application of either UV radiation by flood illumination using a germicidal lamp or application of temperature by flood illumination using a heat gun, the substrate displays no change. The deactivatable component has been deactivated and thus does not undergo any subsequent transitions.

A multi-coloured image displaying blue, red, yellow, green and orange colours can therefore be formed.