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Title:
ADDITIVE COMPOSITIONS AND USES THEREOF
Document Type and Number:
WIPO Patent Application WO/2018/229460
Kind Code:
A1
Abstract:
The invention provides for a particulate additive composition comprising a porous particulate material comprising a reversible colour changing material dissolved in a hydrophobic carrier, wherein the colour changing material and hydrophobic carrier together comprise at least 25% w/w of the particulate additive composition.

Inventors:
LYNCH DANIEL ERIC (GB)
GOUGH LEE DAVID (GB)
HANCU DAN ALEXANDRU (GB)
Application Number:
PCT/GB2018/051554
Publication Date:
December 20, 2018
Filing Date:
June 07, 2018
Export Citation:
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Assignee:
NIVIEST LTD (GB)
International Classes:
C08K9/12
Foreign References:
US20030012943A12003-01-16
Other References:
DATABASE WPI Week 199835, 1998 Derwent World Patents Index; AN 1998-408872, XP002784739
Attorney, Agent or Firm:
WILSON GUNN (BIRMINGHAM) (GB)
Download PDF:
Claims:
CLAIMS

1. A particulate additive composition comprising a porous particulate material comprising a reversible colour changing material dissolved in a hydrophobic carrier, wherein the colour changing material and hydrophobic carrier together comprise at least 25% w/w of the particulate additive composition.

2. A particulate additive composition as claimed in claim 1 wherein the composition further comprises a UV-absorbing material, or the hydrophobic carrier has UV- absorbent properties.

3. A particulate additive composition as claimed in claim 1 or 2 wherein the colour changing material is a leuco dye or a liquid crystal.

4. A particulate additive composition as claimed in claim 3 wherein the leuco dye is a photochromic dye, a thermochromic dye or a halochromic dye.

5. A particulate additive composition as claimed in claim 4 wherein the photochromic compound is selected from a spiropyran, spirooxazine, naphthopyran, benzopyran or chromene compound, spironaphthoxazine, spirobenzoxazine, organo-metal dithizonate, and fulgide or fulgimide compound, and mixtures thereof.

6. A particulate additive composition as claimed in claim 4 wherein the thermochromic compound is selected from a spirolactone, fluoran, thermochromic spiropyran, and thermochromic fulgide.

7. A particulate additive composition as claimed in any preceding claim wherein the colour changing material is present in the composition in an amount of between 0.1 w/w and 25% w/w of the total weight of the composition.

8. A particulate additive composition as claimed in any preceding claim wherein the hydrophobic carrier and colour changing material together comprise between 25% to 90% w/w of the particulate additive composition, preferably between 25% and 75%.

9. A particulate additive composition as claimed in any preceding claim wherein the porous particulate material is present in the composition in an amount of between 5% w/w and 70% w/w of the total weight of the composition.

10. A particulate additive composition as claimed in any preceding claim wherein the porous particulate material is selected from a colourless material, a transparent material and a translucent material.

11. A particulate additive composition as claimed in any preceding claim wherein the porous particulate material is selected from silicon dioxide, synthetic or natural alumina silicate, fly ash, a halloysite clay, or any mixture thereof.

12. An article or product containing a particulate additive composition of any one of claims 1 to 11.

13. An article or product as claimed in claim 12 wherein the article comprises a thermoplastics material, a thermoplastic material, a thermoset material, a thermoplastic elastomer, a natural or synthetic rubber and/or a silicone rubber.

14. An article or product as claimed in claim 12 or claim 13 wherein the particulate additive composition is dispersed substantially homogeneously in at least a portion of the article or product.

15. An article or product as claimed in any one of claims 12 to 14, wherein the article or product is a solid article or product.

16. An article or product as claimed in any one of claims 12 to 14, wherein the article or product is a liquid product.

17. A method of manufacturing a particulate additive composition of any one of claims 1 to 1 1, the method comprising dissolving a colour changing material in a hydrophobic carrier and then impregnating a porous particulate material with the resultant solution of colour changing material.

18. A method as claimed in claim 17, wherein the colour changing material is first dissolved in a secondary carrier, and the resultant solution is then dissolved in the hydrophobic carrier, followed by removal of the secondary carrier.

19. A method as claimed in claim 18, where the secondary carrier comprises a secondary solvent.

20. A method as claimed in claim 19, wherein the secondary solvent comprises an organic solvent, such as toluene.

21. A method of manufacturing an article or product of any one of claims 12 to 16, the method comprising locating a particulate additive composition of any one of claims 1 to 1 1 within and/or on at least a portion of an article or product.

22. A method as claimed in claim 21 wherein the article or product comprises at least a portion comprising a thermoplastics material, a thermoplastic material, a thermoset material, a natural or synthetic rubber and/or a silicone rubber, and wherein the method comprises; heating the material to a flowable state, dispersing the particulate additive composition substantially homogeneously within the material; further processing the resulting mixture of material and particulate additive composition to form at least a portion of the article or product.

23. A method as claimed in claim 22, wherein the method comprises coating solid pieces of the thermoplastics material, thermoplastic material, thermoset material, natural or synthetic rubber and/or silicone rubber with the particulate additive composition, and subsequently melting the pieces.

24. A method as claimed in claim 22 or 23, wherein the further processing comprises extruding, moulding, injection- moulding, blow moulding, film or rota-moulding, two- part liquid moulding, laminating, calendaring, rolling or pressing.

Description:
ADDITIVE COMPOSITIONS AND USES THEREOF

Technical Field of the Invention

This invention relates to particulate additive compositions and in particular to particulate additive compositions for use in colour changing applications. The invention further relates to the use of colour changing particulate additive compositions in articles such as, but not limited to, moulded or extruded articles, coatings, thin film materials and paints.

Background to the Invention

It is known to incorporate photochromic, thermochromic and liquid crystal materials into articles, in order to provide a colour-changing functionality to the article upon application of a suitable physical or chemical stimulus. Thermochromic dyes and inks have been widely used in many industries, including security features applied to, or incorporated into articles such as packaging labels, tags and banknotes. Such thermochromic dyes are generally leuco dyes which change between a colourless, or leuco, state, and a coloured, or non-leuco state. The thermochromic inks are configured to change between a colourless and coloured state on reaching specific temperatures. For example, thermochromic leuco inks may be used which is colourless state at temperatures below -15°C but coloured above -15°C. Such inks may be used, for example, in packaging for temperature-sensitive or perishable goods, such as food-stuffs, pharmaceuticals and the like.

In some known systems, such as those described in US6280838, the dyes or dye solutions are directly compounded into an article such as a thermoplastics material. Thermochromic and photochromic dyes have also been incorporated into porous material, such as a zeolite material or silica particles before subsequent incorporation into articles such as plastics articles. In known methods, such as those described in DE102006033906, the dyes are entrapped in a porous material via a volatile solvent, with the solvent being subsequently removed, such that the dyes are retained in the pores in a dry state through electrostatic forces (such as Van der Waals forces).

In known systems, there are a number of problems. For systems in which a photochromic or thermochromic dye is directly compounded into a final article, the reversible colour change transition time can be relatively slow and the dyes may be easily inactivated through physical or thermal means. For systems in which the dyes are incorporated into porous particles in a volatile solvent, which is subsequently removed to provide solid dye which is electrostatically coated within the pores of the particles, again the dyes will be prone to slow reversible colour changes and inactivation or destruction through physical or thermal means. There are also some systems in which the dyes are microencapsulated, but such capsules are designed for coating formulations such as inks and paints and would not survive compounding into plastics materials due to the shear forces of compounding apparatus.

It is therefore an aim of embodiments of the invention to provide colour change materials which may be incorporated into plastics or other articles, which are stable throughout plastics compounding, and which retain effective colour change (reversibly) in effective timescales, and which do not suffer significant loss of activity in the environment to which the articles are subjected during use.

It would be advantageous to be able to provide a colour change material that can be incorporated into an article, in which the colour change material is effectively protected throughout the manufacturing process, and which retains effective colour change characteristics post manufacture. It would also be advantageous to provide particulate additive compositions in which the load of colour change material is maximised such that the colour-change properties are also maximised.

It is therefore an aim of embodiments of the present invention to overcome or mitigate at least one problem of the prior art.

Summary of the Invention

According to a first aspect of the invention there is provided a particulate additive composition comprising a porous particulate material comprising a reversible colour changing material dissolved in a hydrophobic carrier, wherein the colour changing material and hydrophobic carrier together comprise at least 25% w/w of the particulate additive composition.

The current invention contains three specific elements, (a) a colour changing material dissolved in (b) a hydrophobic carrier that is absorbed into or entrained within (c) a porous particulate material. The colour changing material may comprise a material which can reversibly change between two colour states, one of which may be colourless, upon the application of a chemical or physical stimulus or reaction. In some embodiments the colour changing material may change between a colourless state and a coloured state, whilst in other embodiments the colour changing material may change between two different colours. The colour change may be gradual, and may be over a period of no more than 10 seconds, 15 seconds, 30 seconds, 45 seconds, 60 seconds, 75 seconds, 90 seconds, 105 seconds or no more than 120 seconds, upon application of the effective stimulus. Alternatively, the colour change may be substantially instantaneous or may be over a period of less than 5 seconds, 4 seconds, 3 seconds, 2 seconds or less than 1 second upon the application of the effective stimulus. The colour change may take place between 1 second and 120 seconds from application of the effective stimulus.

The colour changing material may comprise a leuco dye or a liquid crystal, for example.

A leuco dye is a dye which can switch between two chemical forms; one of which is colourless and one of which is coloured. Leuco dyes may undergo reversible transformations caused by many different physical or chemical stimuli, such as heat, light or pH; resulting in examples of thermochromism, photochromism and halochromism respectively.

The colour changing material may be present in the additive composition in an amount of at least 0.1% w/w, 0.2% w/w, 0.3% w/w, 0.4% w/w, 0.5% w/w, 0.75% w/w, 1% w/w, 1.5% w/w, 2% w/w or at least 2.5 % w/w of the particulate additive composition. The colour changing material may be present in the additive composition in an amount of no more than 10% w/w, 7.5% w/w or no more than 5% w/w of the particulate additive composition. In preferred embodiments, the colour changing material may be present in the additive composition in an amount of between 2% and 5% w/w, such as between 2% to 3% w/w. The hydrophobic carrier may be present in the additive composition in an amount of at least 15% w/w, 20% w/w or at least 25 % w/w of the particulate additive composition. The hydrophobic carrier may be present in the additive composition in an amount of no more than 90% w/w, 80% w/w, 70% w/w, 60% w/w or no more than 50% w/w of the particulate additive composition. The colour changing material may be dissolved in the hydrophobic carrier in an amount of at least 0.1% w/w, 0.2% w/w, 0.3% w/w, 0.4% w/w, 0.5% w/w, 0.75% w/w, 1% w/w, 1.5% w/w, 2% w/w, 2.5 % w/w, 3% w/w, 3.5% w/w, 4% w/w, 4.5% w/w, 5% w/w or at least 10% w/w of the solution of hydrophobic carrier and colour changing material. The colour changing material may be dissolved in the hydrophobic carrier in an amount of no more than 10% w/w, 7.5% w/w or no more than 5% w/w of the solution of hydrophobic carrier and colour changing material.

The solution of colour changing material and hydrophobic carrier may together comprise at least 30% w/w, 35% w/w, 40% w/w, 45% w/w, 50% w/w, 55% w/w, 60% w/w, 65% w/w or at least 70% w/w of the particulate additive composition. The solution of colour changing material and hydrophobic carrier may together comprise no more than 95%, 90%, 85%, 80% , 75%, 70%, 60%, 50%, 40%, or no more than 30% of the particulate additive composition. The solution of colour changing material and hydrophobic carrier may together comprise between 25% to 95% w/w, between 25% to 90%, between 25% to 85%, between 25% to 80%, between 25% to 75%, between 25% to 60% w/w, between 25% to 50% w/w, between 30% to 80% w/w or between 30% to 75% w/w of the particulate additive composition.

In preferred embodiments, the colour changing material may comprise between 1% and 10%) w/w, between 2% and 8% w/w or between 3% and 6% w/w of the mixture of hydrophobic carrier and colour changing material, such as around 4% w/w of the mixture of hydrophobic carrier and colour changing material. In some embodiments, the colour changing material may comprise between 1% and 5% w/w of the mixture of hydrophobic carrier and colour change material and the mixture of colour change material and hydrophobic carrier may comprise between 25% to 80% w/w of the particulate additive composition. In especially preferred embodiments, the colour changing material may comprise 4% w/w of the mixture of hydrophobic carrier and colour changing material, and may comprise 2.6% w/w of the overall particulate additive composition.

The porous particulate material may comprise at least 5% w/w, 7.5% w/w, 10% w/w, 12.5% w/w or at least 15% w/w of the additive composition and may comprise up to 60% w/w, or up to 50% w/w of the particulate additive composition. In some embodiments the porous particulate material may comprise between 10% w/w and 50% w/w, or between 15% and 35% w/w, of the particulate additive composition.

The leuco dyes used in the additive compositions of the invention may comprise a photochromic dye, a thermochromic dye, a halochromic dye, a liquid crystal leuco dye, or a mixture thereof, for example.

It is important that the colour change material is dissolved in the hydrophobic carrier material within the porous particulate material, and remains dissolved and in the localised solubilised environment within the particulate material, as this imparts significant advantages to the reversible rate of transition between the two molecular transformations of the colour change material, the resistance of the colour change material to thermal and physical degradation, and also to long term stability under harsh conditions.

Photochromic Dyes

In some preferred embodiments, the leuco dye may comprise a photochromic dye. Many photochromic materials change colour upon irradiation with ultraviolet (UV) or visible light and then revert back to their original colour following removal of the illuminant; this is known as T-type photochromism when the back reaction is driven thermally. If the photochromic material only returns to its original state through irradiation with light of another range of wavelengths, i.e. the change is photochemically driven, then it is said to exhibit P- type photochromism.

The photochromic agent may comprise a P-type photochrome or a T-type photochrome. Suitable photochromic agents include those selected from oxazine derivatives; spirooxazines; chromenes; chromene-derived photochromic compounds such as pyrans; fulgides; iulgimides; and dithizonate organometallic derivatives, as well as mixtures thereof.

Preferred photochromic additives are spiropyrans, spirooxazines, naphthopyrans, benzopyrans or chromene compounds, spironaphthoxazines, spirobenzoxazines, organo-metal dithizonates, and fulgide or fulgimide compounds and mixtures thereof.

Suitable chromene compounds include any known compounds having a chromene skeleton and a photochromic property.

Chromene has the following structure:

Preferred photochromic compounds comprising a chromene moiety may be illustrated by the following formula:

wherein the fragment: represents an optionally substituted, aromatic hydrocarbon radical or an optionally substituted unsaturated heterocyclic radical, R 1 and R 2 represent radicals, being the same or different, selected from a hydrogen atom, an optionally substituted hydrocarbon radical and a substituted amino radical, or combine to form a ring, and R 3 and R 4 represent radicals, being the same or different, selected from a hydrogen atom, an optionally substituted hydrocarbon radical and a substituted amino radical.

Specific examples of chromenes useful in the invention include 2,2-diphenyl-7- octoxy(2H)benzo(f)chromene, spiro(bicyclo[3.3.1 ]nonane-9,2'-(2H)benzo(h)chromene), spiro(norbornane-2,2'-(2H)benzo(h)chromene), 7'-methoxyspiro(bicyclo[3.3.1]nonane-9,2'- (2H)benzo(h)chromene), 7'-methoxyspiro(norbornane-2,2'-(2H)benzo(h)chromene), and 2,2- dimethyl-7-octoxy(2H)benzo(f)chromene.

Amongst these compounds, a first preferred class is that of the naphthopyrans, in particular those having two substituted or not phenyl moieties on the carbon atom in a position adjacent to the oxygen atom of the pyran ring. Such photochromic compounds display an excellent resistance towards degradation induced by radicals in aqueous medium. An example thereof is the following compound (I):

A second preferred chromene derivative class is that of spiropyrans. The preferred spiropyrans comprise the following base moiety:

wherein R represents a linear or a branched alkyl group. The aromatic positions of this compound may be substituted. Example thereof is the following compound (II):

Suitable fulgide compounds include any known compounds having a fulgide skeleton and a photochromic property. Specific examples of fulgides include N-methyl-6,7-dihydro-4- methylspiro(5,6-benzo[b]triiophene-dicarboxyimido-7,2-tricyc lo[3.3.1. ljdecane), N- cyanomethyl-6,7-dihydro-4-methyl-2-phenylspiro(5,6-benzo[b]t hiophenedicarboxyimi 7,2-tricyclo-[3.3.1. l]decane), N-cyanomethyl-6,7-dihydro-4-methyl-2-(p-methoxyphenyl)- spiro(5,6-benzo[b]thiophenedicarboxyimido-7,2-tricyclo-[3.3. 1. l]decane), N-cyanomethyl- 6,7-dihydro-4-methylspiro(5,6-benzo[b]thio-phenedicarboxyimi do-7,2- tricyclo[3.3.1. l]decane), N-cyanomethyl-6,7-dihydro-4-cyclopropylspiro(5,6-benzo[b]- thiophenedicarboxyimido-7,2-tricyclo[3.3.1.1]decane), and 6,7-dihydro-N- methoxycarbonylmethyl-4-methyl-2-phenylspiro(5,6-benzo[b]thi ophenedicarboxyimido-7,2- tricyclo[3.3.1. l]decane).

Preferred oxazine compounds are compounds of the spiro[indohno]benzoxazine, spiro[indolino]naphthoxazine and spiro[indolino]pyridobenzoxazine type. Preferred oxazine compounds include compounds comprising the following base moiety:

wherein R represents a linear or branched alkyi group, and X is a carbon or a nitrogen atom, The aromatic positions of this compound may be substituted. Specific examples of such compounds are the following compounds of formulas (III) to (V):

Suitable spirooxazine compounds include any known compounds having a spirooxazine skeleton and a photochromic property. Specific examples of spirooxazines include l,3,3-trimethyl-spiro(indole-2,3-[3,2-a][l,4]naphthooxazine) , l,3,3-trimethyl-6'- piperidinospiro(indole-2,3 - [3 ,2-a] [ 1 ,4] -naphthooxazine), 6-fluoro- 1 '-methyl-8 '-methoxy-6 '- morpholinodi spiro(cyclo-hexane- 1 , 3 '-(3H)indole-2 '-(2 Ή),3 '-(3H)naphtho(3 ,2-a)( 1 ,4)- oxazine), 1 '-methoxycarbonylmethyl-8 '-methoxy-6'-(4- methylpiperazino)di spiro(cyclohexane- 1 , 3 '-(3H)indole-2 '-(2 Ή), 3 '(3H)-naphtho(3 ,2- a)(l,4)oxazine), Γ-(2-dioxazine-2-yl)ethyl)-6'-moφholinodispiro(cyclohexane - 1,3 '(3H)indole-2 '-(2 Ή),3 '-(3H)naphtho(3 ,2-a)(l ,4)oxazine), 5 -fluoro- 1 '-methyl-6 '- piperidinodispiro(cyclohexane-l,3 '-(3H)indole-2'-(2'H),3 '-(3H)naphtho(3,2-a)(l,4)oxazine), and 8 r -methoxydispiro(cyclohexane-l,3'-(3H)indole-2'-(2'H),3 '-(3H)naphtho(2,3- a)(l,4)oxazine).

Particularly preferred photochromic compounds are chromene derivatives and oxazine derivatives such as benzoxazines and naphthoxazines, in particular spirooxazine derivatives of the spiro[indolino]benzoxazine, spiro[indolino]naphthoxazine and spiro[indolino]pyridobenzoxazine type.

Thermochromic Dyes

In some embodiments, the leuco dye may comprise a thermochromic dye. Suitable thermochromic dyes may comprise one or more thermochromic leuco dyes which display a color change (usually between a colourless (leuco) form and a coloured (non- leuco) form) in dependence on temperature.

The thermochromic leuco dye may comprise an auxiliary ingredient such as an activator. The thermochromic dye may be present in a thermochromic composition comprising the thermochromic dye and an activator. The activator may comprise an acid, which may be a weak acid having a pH of between 2 - 6, for example. The thermochromic composition may comprise microcapsules with the composition located inside a microencapsulating material. Microencapsulation may allow the use of thermochromic leuco dyes in a wider range of materials and products than would otherwise be achievable with non-encapsulated dye. Suitable thermochromic dyes include spirolactones, fluorans, spiropyrans, and thermochromic fulgides. The acid may comprise bisphenol A, parabens, 1,2,3-triazole derivatives, or 4-hydroxycoumarin and act as proton donors, changing the dye molecule between its leuco form and its protonated colored form; stronger acids may make the change irreversible and so a weak acid of pH 2 - 6 is preferred. Thermochromic dyes have less accurate temperature response than liquid crystals. They may be useful for general indicators of approximate temperature or for general colour change requirements, for example. The thermochromic dye may be used in combination with a pigment, and may produce a colour change between the color of the base pigment and the colour of the pigment combined with the colour of the coloured (non-leuco) form of the thermochromic leuco dye, dependent on the temperature of the composition.

Suitable thermochromic leuco dyes are preferably operable in temperature ranges between about -5°C (23°F) and 60°C (140°F).

Liquid Crystals

Some liquid crystals are capable of displaying different colours at different temperatures. This change is dependent on selective reflection of certain wavelengths by the crystallic structure of the material, as it changes between the low-temperature crystallic phase, through anisotropic chiral or twisted nematic phase, to the high-temperature isotropic liquid phase. The twisted nematic phase has the molecules oriented in layers with regularly changing orientation, which gives them periodic spacing. The light passing through the crystal undergoes Bragg diffraction on these layers, and the wavelength with the greatest constructive interference is reflected back, which is perceived as a spectral colour. A change in the crystal temperature can result in a change of spacing between the layers and therefore in the reflected wavelength. The colour of the thermochromic liquid crystal can therefore continuously range from non-reflective (black) through the spectral colours to black again, depending on the temperature. Typically, the high temperature state will reflect blue-violet, while the low- temperature state will reflect red-orange. Since blue is a shorter wavelength than red, this indicates that the distance of layer spacing is reduced by heating through the liquid-crystal state.

The liquid crystal material may be selected from cholesteryl nonanoate, cholesteryl oleyl carbonate, cholesteryl benzoate, cyanobiphenyls, or mixtures thereof, for example.

Mixtures with 3 - 5°C span of temperatures and ranges from about 17 - 23°C to about 37 - 40°C can be composed from varying proportions of cholesteryl oleyl carbonate, cholesteryl nonanoate, and cholesteryl benzoate. For example, the mass ratio of 65 :25: 10 yields a range of 17 - 23°C, and 30:60: 10 yields a range of 37 - 40°C.

The liquid crystal may be microencapsulated.

Hydrophobic Carrier The hydrophobic carrier may be selected from; liquid, oil from plant, mineral, animal and/or synthetic origin; emulsion, including a microemulsion, an oily or aqueous solution, an oily or aqueous gel, an oil-in-water or water-in-oil emulsion, a dispersion of oil in water by means of vesicles, the vesicles being at the oil/water interface; gel, mousse, or any combination thereof.

The hydrophobic carrier may comprise a carrier with some hydrophilic characteristics. The term "hydrophobic carrier" therefore includes substantially completely hydrophobic carriers, but also carriers with some hydrophilic characteristics, such as zwitterionic or amphoteric carriers, liquid lipophilic agents, such as siloxanes, other silicones, hydrocarbons, glycol ethers, glycerine derivatives such as glycerine ethers, perfluorinated amines, perfluorinated and hydrofluoroether solvents, low-volatility nonfluorinated organic solvents, diol solvents and mixtures thereof, 2-ethylhexyl a-cyano-P,P-diphenylacrylate, phospholipids, or surfactants including alkanolamines, phosphate / phosphonates, geminal surfactants, such as but not limited to, gem diol, gem amide alkoxylates, gem and aminoalkoxy thereof, terminated nonionic surfactants, capped silicone surfactants such as nonionic organic silicone polymers, silicone amine derivatives thereof, alkyl alkoxylates, polyol surfactants, and mixtures thereof; silicone based surfactants such as siloxane polymers; ketones, which are liquid at room temperature, such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, isophorone, cyclohexanone and acetone; alcohols, which are liquid at room temperature, such as ethanol, isopropanol, diacetone alcohol, 2-butoxyethanol and cyclohexanol; glycols, which are liquid at room temperature, such as ethylene glycol, propylene glycol and pentylene glycol; propylene glycol ethers, which are liquid at room temperature, such as propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate and dipropylene glycol mono- n-butyl ether; short-chain esters, containing from 3-8 carbon atoms in total, such as ethyl acetate, methyl acetate, propyl acetate, n-butyl acetate and isopentyl acetate; ethers, which are liquid at room temperature, such as diethyl ether, dimethyl ether and dichlorodiethyl ether; aldehydes which are liquid at room temperature, such as benzaldehyde and acetaldehyde, and/or mixtures thereof. The hydrophobic carrier may solubilise the colour changing material directly.

The colour changing material may be covalently bonded to the hydrophobic carrier. In such embodiments, the colour changing material may be a pendant group of and/or may be within/form at least a part of the hydrophobic polymer backbone, if the hydrophobic carrier is an oligomer or polymer.

The hydrophobic carrier should be one that retains solubility of the colour change material when exposed to the specific stimuli required to force the colour change in the colour change material. It is important that the colour change material remains in a localised solubilised state in the particulate composition to ensure the efficiency of reversible transition between the two rearrangement (colour) states. This means that the carrier should not be a carrier that ' sets' or 'cures' upon thermal or chemical reaction (or other applied stimulus) and it also must not be volatile at temperatures < 150°C.

In some embodiments, the hydrophobic carrier is a liquid. In such embodiments, the hydrophobic carrier liquid may have a boiling point of at least 150°C, 175°C, 200°C, 225°C, 250°C, 250°C, 275°C or at least 300°C.

Suitable hydrophobic carrier liquids will depend upon the chemical and physical properties of the colour changing material, but in some embodiments, it may be selected from an aliphatic or aromatic organic liquid, such as nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, C9 aromatics, tetralin, cyclohexanol, «-octanol, ethanediol, 1,2-propandiol, cyclohexanone, ethylene glycol, diethylene glycol, glycerol, diglyme, hexamethylphosphoramide, hexamethylphosphorous triamide, N-methyl-2- pyrrolidone, acetophenone, dimethylformamide, dimethylacetamide, a mineral oil or paraffin oil, for example; an acrylate or methacrylate solvent, such as bisphenol A ethoxylate dimethacrylate, 1,6-hexanediol dimethacrylate, l,2,2,6,6-pentamethyl-4-piperidyl methacrylate, for example; a phenylformamidine, such as N-(4-ethoxycarbonylphenyl)-N'- methyl-N'-phenylformamidine, N,N'-bis(4-ethoxycarbonylphenyl)-N-phenylformamidine, for example; a benzotriazole, such as 3-(2H-benzotriazol-2-yl)-5-(l, l-dimethylethyl)-4-hydroxy- benzenepropanoic acid, -[3-(2-H-benzotriazol-2-yl)-4-hydroxy-5-tert.butylphenyl]pro pionic acid-poly(ethylene glycol) 300-ester, bis{P-[3-(2-H-benzotriazol-2-yl)-4-hydroxy-5- tert.butylphenyl]-propionic acid}-poly(ethylene glycol) 300-ester, linear C7-C9 alkyl 3-[3-(2H- benzotriazol-2-yl)-5-(l, l-dimethylethyl)-4-hydroxyphenyl]propionates, for example; a sebacate ester, such as bis(l,2,2,6,6-pentamethyl-4-piperidyl)sebacate, methyl 1,2,2,6,6- pentamethyl-4-piperidyl sebacate, bis(2,2,6,6-tetramethyl-l-octyloxypiperidin-4-yl)-l, 10- decanedioate, l,8-bis[(2,2,6,6-tetramethyl-4-((2,2,6,6-tetramethyl-l-octyl oxypiperidin-4-yl)- decan-l, 10-dioyl)piperidin-l-yl)oxy]octane, for example.

The hydrophobic carrier preferably contains or is a UV absorber. The carrier may comprise or be a free radical scavenger such as a hindered amine. The hydrophobic carrier may comprise an antioxidant. The hydrophobic carrier may contain UV absorbers or heat stabilisers, or the hydrophobic liquid itself may be a liquid UV absorber, and may further be a heat stabiliser

In some embodiments, the hydrophobic carrier comprises at least two of; or at least three of; a UV absorber, a free radical scavenger, an antioxidant and a heat stabiliser. In some embodiments, the hydrophobic carrier may comprise all four of a UV absorber, a free radical scavenger, an antioxidant and a heat stabiliser.

In yet further embodiments the hydrophobic carrier may be a UV absorber and may comprise one, two or three of a free radical scavenger, an antioxidant and a heat stabiliser. Suitable UV absorbers, free radical scavengers, antioxidant agents and heat stabilisers will depend upon the chemical and physical properties of the colour changing material, but in some embodiments, they may be selected from a phenylformamidine, such as N-(4- ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidine, N,N'-bis(4- ethoxycarbonylphenyl)-N-phenylformamidine, for example; a benzotriazole, such as 3-(2H- benzotriazol-2-yl)-5-(l, l-dimethylethyl)-4-hydroxy-benzenepropanoic acid, β-[3-(2-Η- benzotriazol-2-yl)-4-hydroxy-5-Z-butylphenyl]propionic acid-poly(ethylene glycol) 300-ester, bis(P-[3-(2-H-benzotriazol-2-yl)-4-hydroxy-5-i-butylphenyl]- propionic acid}-poly(ethylene glycol) 300-ester, linear C7-C9 alkyl 3-[3-(2H-benzotriazol-2-yl)-5-(l, l-dimethylethyl)-4- hydroxyphenyljpropionates, for example; a sebacate ester, such as bis(2,2,6,6-tetramethy-4- piperidinyl)sebacate, bis(l,2,2,6,6-pentamethyl-4-piperidyl)sebacate, methyl 1,2,2,6,6- pentamethyl-4-piperidyl sebacate, bis(2,2,6,6-tetramethyl-l-octyloxypiperidin-4-yl)-l, 10- decanedioate, l,8-bis[(2,2,6,6-tetramethyl-4-((2,2,6,6-tetramethyl-l-octyl oxypiperidin-4-yl)- decan-l, 10-dioyl)piperidin-l-yl)oxy]octane, for example; other compounds, such as octadecyl 3 -(3 , 5-di-z-butyl-4-hy droxyphenyl)propionate, poly [ { 6-(l, 1 , 3 , 3 -tetramethylbutyl)amino- 1,3,5- triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidinyl)imino}hexamethylene 2,2,6,6- tetramethyl-4-piperidinyl)imino], l-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine poly condensation product, 2-(3,5-di-i-butyl-4-hydroxybenzyl)-2-«-butylmalonic acid bis(l,2,2,6,6-pentamethyl-4-piperidyl), l-[2-{3-(3,5-di-t-butyl-4- hy droxyphenyl)propionyloxy } -ethyl] -4- { 3 -(3 , 5 -di-t-butyl-4-hy droxyphenyl)propionyloxy } - 2,2,6, 6-tetramethylpiperidine}, 8'-benzyl-7,7,9,9-tetramethyl-3-octyl- 1,3,8- triazaspiro[4,5]undecane-2,4-dione and the polyethylene glycol ether of butyl-2-cyano-3-(4- hydroxy-3-methoxyphenyl)acrylate, for example.

The hydrophobic carrier may comprise two or more hydrophobic solvents as described hereinabove. The carrier may be present in the particulate additive composition in an amount of at least 5% w/w, 10% w/w, 15% w/w, 20% w/w or at least 25% w/w of the total weight of the composition. The carrier may be present in an amount of no more than 90% w/w, 80% w/w or 75%) w/w of the total weight of the composition. It is important for the compositions of the invention to include a relatively large proportion of hydrophobic carrier, in order to ensure optimal protection for the colour changing material dissolved therein, and reduce the possibility of thermal degradation thereof during use of the compositions.

Porous Particulate Material

The porous particulate material may comprise finely divided powder which acts as a solid support for the colour changing material dissolved in a hydrophobic carrier.

The particulate material may comprise colourless, transparent or translucent particles.

The particulate material may comprise particles having an average particle diameter (or largest dimension) of at least 10 nm, 15 nm, 20 nm, 25 nm, 50 nm, 100 nm, 250 nm, 500 nm, 750 nm or at least 1 μιη. The particles may have an average particle diameter (or largest dimension) of no more than 1 mm, 750 μιη , 500 μπι, 250 μιη, 150 um or 100 μιη. The particles may have an average particle diameter (or largest dimension) of between 10 nm and 500 μπι, or between 10 nm and 250 μπι, or between 10 nm and 400 μπι.

The pores of the porous particulate material may have an average pore size of at least 0.01 nm, at least 0.02 nm, at least 0.03nm, at least 0.04 nm, at least 0.05 nm, or at least 0.1 nm. The pores may have an average pore size of up to 100 μιτι, 75 μπι, 50 μπι or 40 μιη. The size of the pores will be restricted by the average particle size, and so particles having an average particles size of up to 1 μιη, may, for example, have pores in the 0.01 nm to 0.05 μιη range, while particles having an average particle size of at least 100 μιη or above may have pore sizes in the micron range, such as between 1 μηι and 40 μηι, for example.

The porous particulate material may comprise particles comprising an open porous network through at least 25%, 50%, 75% or even at least 80% of the particles. By "open porous network" we mean that each pore in the particle is in communication with at least one adjacent pore, which forms a network of interconnected pores, through which the dissolved colour change material may disperse, in use.

The particles may comprise granules or powder.

The particulate material may comprise templated, precipitated or fumed silicon dioxide, synthetic or natural alumina silicate, fly ash, halloysite clays (e.g. Dragonite (RTM)), zeolite materials, any other porous inorganic or organic particle capable of absorbing a hydrophobic carrier, or any combination thereof. In some embodiments, the particulate material comprises silicon dioxide powder having an average particle size of between 10 nm and 400 μιη.

The porous particulate material may comprise particles with a single pore, cavity or void, or may comprise particles which have a plurality of pores, cavities or voids. In embodiments where the porous particulate material comprises particles with a single pore, cavity or void, the particles may comprise an at least partially hollow shell which may have a single main pore void, wherein the main pore void may comprise at least 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98% or at least 99% of the entire volume of the hollow shell. In embodiments where the porous particulate material comprises a plurality of pores, cavities or voids, the particles may comprise an at least partially hollow shell comprising a plurality of pore voids which may comprise at least 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98% or at least 99% of the entire volume of the hollow shell. In such embodiments, the hollow shell may comprise internal scaffolding which may separate a single pore, void, cavity, or pore void into a plurality of pores, voids, cavities or pore voids. At least a portion of the pores, cavities, voids and/or pore voids may be in fluid communication with each other and/or with the space outside the particulate material.

According to a second aspect of the invention there is provided an article or product containing a particulate additive composition of the first aspect of the invention.

The article or product may be a cosmetics article or product. The cosmetics article or product may be selected from eye shadow, eye liner, mascara, lipstick, lip gloss, lip balm and nail varnish for example. In such embodiments, the hydrophobic carrier may comprise a carrier approved for use on human skin, for example fatty substances, such as gums and/or waxes. Waxes may be, but are not limited to, hydrocarbon-based, fluorine-based and/or silicone-based and may be of plant, mineral, animal and/or synthetic origin. Suitable waxes include, but are not limited to, lanolin, beeswax, camauba wax or candelilla wax, paraffin, lignite wax, microcrystalline wax, ceresin or ozokerite, synthetic waxes such as polyethylene waxes, Fischer-Tropsch waxes, silicone waxes such as alkyl- or alkoxydimethicone containing from 16-45 carbon atoms, and mixtures and/or derivatives thereof. Suitable gums include organopolysiloxanes such as PDMS with an average molecular weight of from 1,000-500,000. Suitable fatty substances, which are liquid at room temperature, include, but are not limited to, hydrocarbon-based oils of animal origin such as perhydrosqualene; hydrocarbon-based plant / vegetable oils such as liquid triglycerides of fatty acids of 4-10 carbon atoms such as triglycerides of heptanoic and octanoic acids, or alternatively sunflower oil, corn oil, soybean oil, marrow oil, grapeseed oil, sesame oil, hazelnut oil, apricot oil, macadamia oil, castor oil, avocado oil, caprylic / capric acid triglycerides, jojoba oil, karite butter, lemon oil, orange oil, lavender oil, citronella oil, rosemary oil, eucalyptus oil, mint oil, cinnamon oil, pine oil, Artemisia oil, marjoram oil, or savory oil; linear or branched hydrocarbons of mineral or synthetic origin such as liquid paraffins and derivatives thereof, petroleum jelly, polydecenes, hydrogenated polyisobutene such as parleam; isoparaffins such as isohexadecane and isodecane; synthetic esters and ethers, in particular those of fatty acids such as the oils of formula R-COOR' in which R is a higher fatty acid residue comprising from 7-29 carbon atoms and R' is a hydrocarbon-based chain containing from 3-30 carbon atoms such as, for example, purcellin oil, isopropyl myristate, 2-ethylhexyl palmitatic, 2-octyldodecyl stearate, 2- octyldodecyl erucate, isostearyl isostearate, hydroxylated esters such as isostearyl lactate, octylhydroxystearate, octyldodecyl hydroxystearate, diisostearyl malate, triisocetyl citrate, heptanoates, octanoates and decanoates of fatty alcohols, polyolesters such as propylene glycol dioctanoate, neopentyl glycol diheptanoate, diethylene glycol diisononanoate; and pentaerythritol esters, fatty alcohols containing from 12-26 carbon atoms such as octyldodecanol, 2-butyloctanol, 2-hexyldecanol, 2-undecylpentadecanol and oleyl alcohol; partially hydrocarbon-based and/or silicone-based fluoro oils; non-volatile silicone oils, linear or cyclic polymethylsiloxanes (PDMS) which are liquid or pasty at room temperature; phenylsilicones such as phenyltrimethicones, diphenyldimethicones, phenyldimethicones and phenyltrimethylsiloxydiphenyl siloxanes, fluoro oils and fluorosilicone oils, and/or mixtures and/or derivatives thereof. Fatty substances may also include the polyoxyalkylenes dextrans, fatty acid esters of saccharose, fatty alcohol ethers of oligoglucosides (for example the alkylpolyglucosides), fatty acid esters of glycerol (for example glycerol mono/distearate or glycerol monolaurate), and polyoxyethylene type compounds (for example polyoxyethylene (POE), polyethylene glycol (PEG), polyethylene oxide (PEO)). The latter also include polyethoxylated fatty acid esters of sorbitan (for example polysorbates), fatty acid esters of poly(ethylene oxide) (for example polyoxyethylene stearates), fatty alcohol ethers of poly(ethylene oxide) (for example polyoxyethylated lauryl ether), alkylphenol ethers of poly(ethylene oxide) (for example polyethoxylated octylphenol), polyoxyethylene- polyoxypropylene block copolymers (also known as poloxamers), and ethoxylated fats and oils (for example ethoxylated castor oil, or polyoxyethylated castor oil, also known as polyethylene glycol-glyceryl triricinoleate), and/or mixtures and/or derivatives thereof.

The article or product may be a polymeric article or product or an article or product comprising a polymeric material, in preferred embodiments. The particulate additive composition may be dispersed within at least a portion of the polymeric article or product, and may be dispersed throughout the polymeric article or product or may be dispersed within the polymeric article or product at or adjacent to a surface thereof. Alternatively, the particulate additive composition may be dispersed in multiple areas of the polymeric article or product. The polymeric article or product may comprise a thermoplastic material, a thermoplastics material, an elastomeric material, a thermoset material, a natural or synthetic rubber, and/or a silicone rubber, or a mixture of any two or more of the aforementioned materials. The polymeric article or product may comprise layers or separate portions, each of which may independently comprise one or more of a thermoplastic material, a thermoplastics material, an elastomeric material, a thermoset material, a natural or synthetic rubber and/or a silicone rubber. At least one layer or portion comprises the particulate additive material of the invention, and each other layer or portion may independently comprise the same particulate additive material, a different particulate additive material, or no particulate additive material.

The polymeric material or article or product, or each layer or portion thereof may comprise a synthetic polymer or a natural polymer.

Suitable thermoplastic materials include polyamides (such as nylon), acrylic polymers, polystyrenes, polypropylene (PP), polyethylene (including low-density polyethylene (LDPE) and high density polyethylene (HDPE), acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), polyglycolic acid, polycarbonates, polybenzimidazole, poly ether sulphone, polyether ether ketones (PEEK), polyetherimide, polyphenylene oxide, polyphenylen sulphide, polyvinyl chloride (PVC), and polytetrafluoroethylene (PTFE), polyoxymethylene (POM), cellulose acetate or derivatives thereof, or any suitable mixture of the aforesaid compounds. Suitable thermoset polymers include epoxy resins, melamine formaldehyde, polyester resins and urea formaldehyde, for example.

Suitable elastomers include natural and synthetic rubbers, chloroprene, neoprene, isoprene, polybutadiene, butyl rubber, halogenated butyl rubber, styrene-butadiene, nitrile rubber, latex, fluoroelastomers, silicone rubbers, epichlorhydrin, poly ether block amides and ethylene vinyl acetate (EVA), for example. The elastomer may comprise a thermoplastic elastomer, which may be selected from styrenic block copolymers (TPE-s), thermoplastic olefins (TPE-o), elastomeric alloys (TPE-v or TPV), thermoplastic polyurethanes (TPU), thermoplastic copolyester (TPE-E) and thermoplastic polyamides, for example.

Suitable acrylic polymers (which may be thermoplastics, thermosets or thermoplastic elastomers) include polyacrylic acid resins, polymethyl methacrylates (PMMA), polymethyl acrylates, polyethyl acrylates, polyethyl ethacrylates, and polybutyl methacrylates, for example.

The polymeric material may be cross-linked.

The particulate additive composition of the invention may comprise at least 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.75%, 1%, 1.5% or at least 2% of the total weight of the article or product, or portion or layer thereof.

The particulate material comprising colour change material (dissolved in the carrier) located therein, may uniformly disperse in plastics materials. This system allows the colour change material to be retained in a localised solubilised state (dissolved in the hydrophobic carrier) while being supported by a robust framework in a solid / solidified plastics material. The particulate material provides protection for the colour change material both physically and thermally.

If said plastics material is a thermoplastics, thermoset or thermoplastic elastomer material then dispersion of the particulate material into the plastics material may occur upon the application of heat to melt the material, and the colour change material may not decompose due to the heat applied.

The particulate additive composition of the invention will not impair the plasticity or other properties of any plastics material when the additive composition is introduced into the plastics material.

The particulate material may also help significantly reduce the migration of the colour change material dissolved in a hydrophobic carrier through the plastics material to prevent build-up of the colour change material on the surface of the plastics material.

The article or product may comprise a solid article or product or may comprise a liquid product. The solid article or product may be rigid or flexible.

The solid article or product (or layer or portion thereof) may comprise a compounded article or product such as a compounded pellet, an extruded article or product, injection- moulded article or product, blow moulded article or product, film or rota-moulded plastics article or product, two-part liquid moulded article or product, laminate, 3D printer filament, felt, woven fabric, knitted fabric, embroidered fabric, nonwoven fabric, geotextiles, fibres or a solid sheet, for example. The liquid product may comprise paint, a coating material, a varnish, a cosmetic (liquid, gel, mousse, cream or the like, for example) (such as nail varnish), a liquid stain or a curable liquid polymer, for example.

By "liquid product", we include gels, mousses, creams, and other flowable products, as well as liquids per se.

According to a third aspect of the invention there is provided a method of manufacturing a particulate additive composition of the first aspect of the invention, the method comprising dissolving a colour changing material in a hydrophobic carrier and then impregnating a porous particulate material with the resultant solution of colour changing material.

The hydrophobic carrier may solubilise the colour changing material directly.

The hydrophobic carrier may solubilise the colour changing material indirectly. In such embodiments, the method may comprise dissolving the colour changing material in a mixture of hydrophobic carrier and a secondary carrier such that the colour changing material is substantially fully dispersed in the hydrophobic carrier, and then removing the secondary carrier. The method may comprise dissolving the colour changing material in the secondary carrier, followed by addition of the hydrophobic carrier. The hydrophobic carrier may solubilise the colour changing material upon removal of the secondary carrier. The hydrophobic carrier may be miscible with the secondary carrier. In preferred embodiments, the secondary carrier dissolves and/or is miscible with and/or solubilises both hydrophobic carrier and colour changing material. In such embodiments, the secondary carrier may be removed to leave a solution of colour changing material and hydrophobic carrier. The secondary carrier may comprise a secondary solvent. The secondary carrier/secondary solvent may comprise an organic solvent, such as toluene. According to a fourth aspect of the invention there is provided a method of manufacturing an article or product of the second aspect of the invention, the method comprising locating a particulate additive composition of the first aspect of the invention within and/or on at least a portion of an article or product.

In some embodiments, the article or product is a solid body and the particulate additive composition may be coated or absorbed onto the surface of the article or product. The article or product may be a textile article or product and the particulate additive composition may be coated onto at least one surface of fibres of the textile material, and may impregnate the fibres.

In embodiments where the article or product comprises a thermoplastics material, a thermoplastic material, a thermoset material, a natural or synthetic rubber and/or a silicone rubber, the method may comprise; heating the material to a flowable state, dispersing the particulate additive composition substantially homogeneously within the material; further processing the resulting mixture of material and particulate additive composition to form at least a portion of the article or product. In such, embodiments, the particulate additive composition may be coated onto the solid thermoplastics material, thermoplastic material, thermoset material, natural or synthetic rubber and/or silicone rubber, followed by subsequent melting, and the further processing of the material may comprise extruding, moulding, injection- moulding, blow moulding, film or rota-moulding, two-part liquid moulding, laminating, calendaring, rolling or pressing, for example.

In some embodiments, the method comprises providing pieces of a thermoplastics material, a thermoset material, a thermoplastic material, a thermoplastic elastomer material, a natural or synthetic rubber and/or a silicone rubber; coating the pieces with a composition of the first aspect of the invention, and melting the pieces. Thus, the coated pieces, when melted, will blend homogeneously and the particulate additive composition will disperse within the blended polymeric article.

In other embodiments, the product may be a liquid product, such as paint or cosmetic (including gel, mousse, cream or the like, for example), and the particulate additive composition may be dispersed within the liquid. The liquid product may be a gel, mousse, cream, or other flowable product, as well as liquids per se.

The article or product may be substantially the same as the articles and products as described for the second aspect of the invention.

The method may be used to locate a particulate additive composition of the first aspect of the invention within and/or on at least a portion of an article or product after the article or product has already been manufactured.

The method may be used to locate a particulate additive composition of the first aspect of the invention within and/or on at least a portion of an article or product during its manufacture. According to a fifth aspect of the invention there is provided use of a particulate additive composition of the first aspect of the invention in imparting colour change character to at least a portion of an article or product.

The article or product may be as described for the second aspect of the invention.

Detailed Description of the Invention Embodiments of the invention will now be described by way of example.

Examples Example 1 Preparation of a particulate additive composition of the invention in the form of a colour changing photochromic additive powder

2.8 grams of PS 7-219 (a photochromic colour changing material supplied by PPG Corp.) were dissolved in 300 mL of toluene (as a secondary solvent) by mechanical stirring. This solution was then dissolved in 70 grams of SR540 (a hydrophobic carrier liquid, supplied by Arkema), with additional stirring. Following dissolution of the two liquids the toluene (secondary solvent) was removed by heat induced evaporation to leave 72.8 grams of final mixture. This mixture was then used to impregnate porous finely divided silicon dioxide powder in a 2: 1 w/w ratio of mixture to porous finely divided silicon dioxide powder and mixed until all of the resultant powder was free-flowing. The resultant particulate additive composition of the invention consisted of a porous particulate material in which a solution of dissolved photochromic material is entrapped, with the photochromic material in a local liquid (SR540) environment in the pores of the particulate.

Examples 2 - 13

Particulate additive compositions according to the invention were prepared in the same manner as Example 1 above, with a range of leuco dyes dissolved in either SR540 carrier liquid (Examples 6-13), SR540 carrier and Zikasorb-BS (a hydrophobic carrier with UV absorber, supplied by Devine (Examples 2-4)), or in Zikasorb-BS alone (Example 5), and the resultant mixture entrained in porous finely divided silicon dioxide powder, as described above for Example 1. Table 1 sets out the various mixtures used.

Example Colour Manufacturer SR540 liquid carrier Zikasorb-BS (UV

Change Dye containing dissolved absorber) (grams) colour change dye

(grams)

2 PS 7-219 PPG Corp 52.5 17.5

3 PS 7-219 PPG Corp 35 35

4 PS 7-219 PPG Corp 17.5 52.5

5 PS 7-219 PPG Corp 70

(reference

example)

6 PS 7-2350 PPG Corp 70

7 PS 7-1497 PPG Corp 70

8 PS 7-2258 PPG Corp 70

9 Reversacol Vivimed 70

Mulberry Labs

10 Reversacol Vivimed 70

Sunflower Labs

1 1 Reversacol Vivimed 70

Heather Labs

12 Reversacol Vivimed 70

Sea Green Labs

13 Reversacol Vivimed 70

Ruby Labs

Table 1 : Particulate additive compositions according to the invention

Examples 2, 3 and 4 were prepared using mixtures of SR540 and Zikasorb-BS (Devine Chemicals) as the hydrophobic carrier liquids; Example 5 was prepared using only Zikasorb- BS as the hydrophobic carrier liquid; and Examples 6-13 were prepared using only SR540 as the hydrophobic carrier liquid. Each mixture was used to impregnate finely divided silicon dioxide powder at a 2: 1 w/w ratio of mixture to finely divided silicon dioxide powder.

Examples 14 - 26 Production of injection moulded articles of the invention

8.0 grams of each of the powder mixtures (particulate additive compositions) from examples 1 - 13 were evenly coated over separate batches of 400 grams of HDPE pellets in a rotating mixing drum before the coated pellets were added to the hopper of an injection moulding machine that produced 90 mm diameter x 3 mm thick disks, for further testing. When exposed to bright sunlight each set of disks changed colour according to Table 2 below.

Examples 27 - 29

20.0 grams of each of the powder mixtures from examples 9, 10 and 12 were evenly coated over separate batches of 2 kgs of nylon-6 pellets in a rotating mixing drum before the coated pellets were added to the hopper of an injection moulding machine that produced 80 mm square x 3 mm thick plates, for further testing. When exposed to bright sunlight each set of disks changed colour according to Table 2 below.

Example Example powder Colour without Colour with

sunlight sunlight

14 - 18 1 - 5 Light purple Dark purple

19 6 Light green Dark blue

20 7 Light purple Purple-black 21 8 Off-white Dark brown

22 9 Light purple Dark purple

23 10 Light yellow Dark yellow- orange

24 1 1 Light purple Dark purple

25 12 Light green Dark green

26 13 Light pink Dark purple-red

27 9 Light purple Purple

28 10 Light yellow Yellow-orange

29 12 Light green Blue-green

Table 2: results of colour change achieved in articles comprising particulate additive compositions of Examples 14-29.

The colour change for all Examples in Table 2 was completed within 30 seconds and the reverse colour change (back to the original colour or colourless) was completed within 5 mins following removal from both direct and indirect UV exposure.

Example 30 UV exposure tests

Disks produced in examples 14 - 18 were half covered and subjected to continuous UV radiation exposure in a QUV machine at 60°C with disks being removed at 16 hours and 96 hours, and were visually analysed in both active and inactive states.

After 16 hours, example 14 had photo-bleached in the exposed areas, although still retained some colour change in the active state. After 96 hours, examples 15 - 17 had photo- bleached in the exposed areas, although still retained some colour change in the active state, with discolouration (or 'browning') of the plastic evident in the exposed areas in the inactive state. After 96 hours continuous UV exposure, example 18 remained unaffected in both active and non-active states, in comparison of exposed and non-exposed areas of the disks.

The results indicate that whilst the use of a hydrophobic carrier alone confers adequate protection on the photochromic compound, the use of a UV absorber in addition to the hydrophobic carrier (such as provided by Zikasorb-BS alone) ensures that any photo-based damage to the photochromic material and article in which it is placed, is mitigated or avoided for a much longer period of time.

Examples 31 - 35 Preparation of photochromic nail polish 200 milligrams of each of the powder mixtures from examples 1, 6, 9, 10 and 12 were separately mixed by stirring into 10 grams of a commercial clear nail polish lacquer, and were then applied by brushing onto plastic false nails. The colour changes observed in Table 2 for each example were also observed for the coated false nails upon exposure and removal from sunlight.

Examples 36 - 40 Preparation of photochromic varnish

200 milligrams of each of the powder mixtures from examples 1, 6, 9, 10 and 12 were separately mixed by stirring into 10 grams of a commercial clear varnish, and were then applied by brushing onto white plastic test panels made of polypropylene. The colour changes observed in Table 2 for each example were also observed for the coated plastic test panels upon exposure and removal from sunlight. Example 41 - 45 Production of extruded articles

90 grams of each of the powder mixtures from examples 1, 6, 9, 10 and 13 were evenly coated over separate batches of 6 kg of cellulose acetate pellets in a rotating mixing drum before the coated pellets were added to the hopper of an extrusion moulding machine that produced 1 mm thick extruded sheets. The colour changes observed in Table 2 for each example were also observed for test pieces cut from each of the extruded sheets.

Examples 46 - 52

8.0 grams of powder mixture from example 5 was evenly coated over separate batches of 400 grams of AB S, PLA, PMMA, POM, PP, TPE, and TPU pellets in a rotating mixing drum before the coated pellets were added to the hopper of an injection moulding machine that produced 90 mm diameter x 3 mm thick disks, for further testing. When exposed to bright sunlight each set of disks changed colour according to example 18 in Table 2.

Example 53

2.8 grams of PS 7-219 were dissolved in 300 mL of toluene by mechanical stirring. This solution was then dissolved in 70 grams of a mixture of Tinuvin 292 and Tinuvin 384-2 (both hydrophobic carrier liquids, supplied by BASF), with additional stirring. Following dissolution of the component liquids the toluene was removed by heat induced evaporation to leave 72.8 grams of final mixture. This mixture was then added to a 2: 1 w/w ratio of mixture to porous finely divided silicon dioxide powder and mixed until all of the resultant powder was free- flowing. 8.0 grams of the powder mixture was evenly coated over separate batches of 400 grams of HDPE pellets in a rotating mixing drum before the coated pellets were added to the hopper of an injection moulding machine that produced 90 mm diameter x 3 mm thick disks, for further testing. When exposed to bright sunlight each set of disks changed colour according to example 18 in Table 2.

The above embodiments are described by way of example only. Any variations are possible without departing from the scope of the invention as defined in the appended claims.