Technical field

The present invention relates to homecare or personal care articles for carrying out multistep treatments, in particular homecare or personal care wipes.

Background

For many types of homecare and personal care applications, it is advantageous to carry out multiple treatment steps in order to achieve a desired effect.

Typically, these multiple treatment steps are provided using separate products which are applied individually. However, this is not so convenient for the consumer, since it requires them to purchase and store separate products, and often consult detailed instructions to carry out the treatment effectively. If the instructions are not followed strictly, this can result in poor results, or can even be dangerous or damaging.

The need for multiple treatment steps may be dictated by the desired effect to be achieved, for example, ingredients used during a washing step may be different to those used during a conditioning step. Additionally or alternatively, multiple step treatment may be necessary in order to avoid unwanted interaction between constituent ingredients which would otherwise render the ingredients inactive e.g. through being broken down, or through having their activity masked.

It is known to provide dissolvable products which provide multistep treatments by exploiting differences in dissolution rate. For example, it is known to provide pressed- powder multi-layer dishwasher tablets with two layers which dissolve at different times during a wash. However, the need to completely dissolve the product in water is inconvenient or, with water-sensitive ingredients, impossible. Furthermore, handling of the product requires direct contact with the active ingredients, which rules out the use of such tablets with certain types of ingredient (e.g. corrosive chemicals). Finally, this product format requires the relevant active ingredients to be formulated into a stable powder capable of being pressed into a tablet and being self-supporting, which can be difficult to achieve with many types of ingredients. Thus, there remains a need to provide more convenient homecare and personal care products for carrying out multistep treatment protocols, which are relatively simple to use and applicable to a range of different active ingredient types.

Summary of the invention

In view of the above, it is an aim of the present invention to provide storage stable multi-ingredient homecare and personal care products which can be used in multi-step treatments, and can be used straight from the packet.

To this end, at its most general, the present invention provides an article suitable for providing a multistep homecare or personal care treatment, comprising:

(i) a substrate;

(ii) a lower layer provided on the substrate; and

(iii) an erodible upper layer at least partially overlaying the lower layer;

wherein the upper layer comprises a first composition providing a first homecare or personal care benefit, and the lower layer comprises a second composition providing a second homecare or personal care benefit.

Advantageously, the upper layer is erodible such that, in use, it is broken down to expose the lower layer underneath for subsequent use. In this way, the upper and lower layers are used sequentially in a relatively straightforward manner to provide the first and second benefits in sequence.

Furthermore, the substrate underlying the lower layer helps to protect the underside of the lower layer from use or damage. This provides an advantage over conventional two- layer dishwasher tablets, where both layers contact water at the same time. In addition, the substrate may reinforce the multilayer structure so as to reduce the effect of mechanical stresses and strains which would otherwise break an equivalent unsupported multilayer structure apart. Furthermore, the substrate provides a means by which the consumer can handle the article, without requiring them to make direct contact with the active layers of the product.

In particular, the article of the present invention allows application of the upper and lower layers directly onto a surface, whilst handling the product via the substrate. This is in contrast to dishwasher tablets where the active ingredients require dispersal/dissolution in water before being used, and are not intended to withstand the forces associated with directly applying the product mechanically to a surface. The ability to apply active ingredients directly to a surface using the article of the present invention opens up a range of different homecare or personal care applications and products, in particular those using water-incompatible ingredients.

By“erodible” we mean that the upper layer disintegrates (breaks down) or is gradually worn away upon application of a mechanical force or a suitable chemical or physical stimulus.

For example, the upper layer may be spreadable, abradable (worn down by rubbing or scraping), or friable (capable of crumbling upon application of a mechanical force). Most preferably, the upper layers are spreadable or abradable. The amount of force required to erode the upper layer is adapted to the particular application. For example, when the article is intended to be rubbed against a surface by hand, the amount of mechanical force required to erode the upper layer is designed to be within the limits which can be delivered by hand, e.g. causing erosion of the layer when the layer is pressed against a surface with a pressure of 5 N, 10 N, 20 N or 50 N and moved across said surface.

Additionally or alternatively, the upper layer may be soluble so that it dissolves in a suitable solvent, e.g. water-soluble (for example, at a temperature of 20°C, 30°C, 40°C, or 50°C).

The lower layer may also be erodible, for example, soluble.

Preferably, the article is suitable for rubbing against a surface to provide a homecare or personal care benefit. In such embodiments, the upper layer of the article erodes upon application of a mechanical force. For example, the upper layer may be abradable, spreadable or friable. In this way, the upper layer is broken down by rubbing against said surface, so as to expose the lower layer underneath for subsequent use. Suitably, in instances where the upper and lower layers are for rubbing aganst a surface, the upper and, optionally, lower layers are wholly or partially transferred onto said surface when rubbed. Advantageously, the consumer can handle the substrate and use this to rub the upper and lower layers sequentially against the surface.

Preferably, the article is in the form of a wipe article. By“wipe article” we mean a sheet which can be rubbed against a surface to provide a homecare or personal care benefit. For example, the wipe article may be a cloth, pad, sponge or tissue. Advantageously, a wipe article allows the consumer to easily handle and rub the article against a surface in order to provide the desired homecare or personal care benefits. This is in contrast to, for example, multi-layer dishwasher tablets, whose pressed-powder construction is liable to crumble in its entirety when mechanical forces are applied, and requires the user to touch the active products when handling.

Configuration

The upper layer and lower layers at least partially overlap/overly one another. The amount of the upper layer overlaying the lower layer may be, for example, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% or 100%. The amount of the lower layer underlying the upper layer may be, for example, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% or 100%. The amount of overlap is assessed based on the projections of the layers onto the substrate when viewed from above (i.e. perpendicular to the surface of the substrate), by calculating the overlapping projected area of the layer as a percentage of the overall area of the projected layer.

In embodiments in which the lower and upper layers at least partially overlap/overlay, the two layers may be directly in contact with one another (i.e. without any intervening layers). Alternatively, the two layers may be separated by an intervening layer. The intervening layer may act as a protective membrane or“barrier layer” between the upper and lower layers. Optionally, the intervening layer lacks any active ingredients. The intervening layer may be made from any of the matrix materials described in relation to the upper and lower layers.

The lower layer may be directly bonded to the substrate (i.e. without any intervening layers). In embodiments in which there is only partial overlap between the lower and upper layers, both layers may be directly bonded to the substrate. Optionally, the upper layer completely overlays the lower layer. For example, the lower layer may be encased/enclosed by the upper layer - i.e. such that that the portions of the lower layer not in contact with the substrate are covered by the upper layer.

The lower and upper layers may take the form of a sheet or film, e.g. a planar sheet or film. The layers may each have a thickness of, for example, 0.25 mm or more, 0.5 mm or more, 0.75 mm or more, 1 mm or more, 1.5 mm or more, 2 mm or more, 3 mm or more, 4 mm or more, 5 mm or more, 7.5 mm or more, 10 mm or more, or 20 mm or more. The maximum thickness of each of the layers is not particularly limited, but may be, for example, 50 mm, 40 mm, 30 mm, 20 mm, 10 mm, 5 mm, 4 mm, 3 mm, 2 mm, or 1 mm.

The provision of the upper and lower layers on a substrate allows the absolute thickness of the layers to be relatively small. In particular, the reinforcement provided by the substrate allows the formation of thin, high surface area layers which would be

insufficiently mechanically robust to exist in a free-standing form. Advantageously, the high surface area of the layers can be used to achieve fast delivery of the components during treatment, e.g. fast dissolution characteristics and/or quick transfer of the components when rubbed against a surface.

Thus, the present invention also covers articles in which the overall thickness of the upper and lower layers is relatively small, and is small compared to the layers’ lateral dimensions. For example, the overall combined thickness of the upper and lower layers may be 10 mm or less; 5 mm or less; 4 mm or less; 3 mm or less; or 2 mm or less. The aspect ratio (the ratio of the longest lateral dimension of the multilayer structure to its thickness) may be at least 2:1 ; at least 3:1 ; at least 4:1 ; at least 5:1 ; at least 7:1 ; at least 10:1 ; at least 15:1 ; or at least 20:1.

The article may have only the lower and upper layers. Alternatively, the article may incorporate further layers, in addition to the upper and lower layers. In this regard, it should be noted that the word“upper” and“lower” are intended to indicate the relative location of each of the said layers, and should not be considered to be synonymous with “uppermost” and“lowermost”. As mentioned above, the reinforcement provided by the substrate allows the formation of relatively thin structures having a high aspect ratio (length:thickness) which would be insufficiently mechanically robust to exist in a free-standing form. Thus, advantageously, the articles of the present invention may have an overall thickness of 10 mm or less, 7 mm or less, 5 mm or less, 4 mm or less, 3 mm or less or 2 mm or less. Additionally or alternatively, the ratio of the length dhickness of the article may be at least 3:1 ; at least 4:1 ; at least 5:1 ; at least 7:1 ; at least 10:1 ; at least 15:1 ; or at least 20:1.

Substrate

The substrate provides a surface on which said lower and upper layers are arranged.

Optionally, the substrate is an applicator - a part which is suitable for consumers to handle so as to allow application of the lower and upper layers to a surface.

Suitably, the substrate has an active face, having the lower and upper layers arranged thereon, and a handling face for the consumer to hold and use the article. This is particularly useful when the article rubbed against a surface by a user, since the substrate can provide a safe area for a user to handle.

For ease of handling, the substrate may be relatively larger than the layers provided thereon. For example, the substrate may be longer, wider and/or deeper than both layers. This minimises the chances of the consumer contacting the active layers when handling the article.

The substrate may be in the form of a sheet material, such as a sheet or film. For example, the substrate may take the form of a sheet material having a length

(corresponding to the longest lateral dimension) of at least 0.5 cm, at least 1 cm, at least 2 cm, at least 3 cm, or at least 5 cm. The average thickness of the sheet material is not particularly limited but may be, for example, at least 100 pm, at least 200 pm, at least 300 pm, at least 400 pm, at least 500 pm, at least 750 pm, or at least 1000 pm (as measured, for example, by determining the mean thickness based on the thickness at five equally spaced points along the length of the sheet material). The surface area of the substrate may be at least 1 cm ² , at least 2 cm ² , at least 3 cm ² , at least 4 cm ² , at least 5 cm ² , or at least 10 cm ² .

Suitably, the substrate is mechanically robust, in particular non-friable. The substrate may be flexible. Alternatively, the substrate may be rigid. Advantageously, this allows the consumer to handle and manipulate the substrate without the article disintegrating.

The substrate may be made from, for example, polymer, fibrous materials including fabrics, paper, or cardboard.

The substrate may be water insoluble at a temperature below 25°C, below 30°C, below 40°C, below 50°C, below 60°C, below 70°C, or below 80°C. For example, the weight of the substrate may remain unchanged (less than 1 wt.% difference) when immersed in distilled water at one of the above temperatures for a period of one hour.

Alternatively, the substrate may be water soluble at a temperature below 25°C, below 30°C, below 40°C, below 50°C, below 60°C, below 70°C, or below 80°C. For example, the weight of the substrate may change by at least 5 wt.%, at least 10 wt.%, at least 20 wt.%, at least 30 wt.%, at least 40 wt.% at least 50 wt.%, or at least 75 wt.% when immersed in distilled water at one of the above temperatures for a period of one hour, or the substrate may completely dissolve when immersed as above.

The substrate may be free or substantially free of active ingredients, in particular homecare or personal care active ingredients.

Compositions

The first and second compositions impart specific homecare or personal care benefits to the article. By“benefit” we mean a specific homecare or personal care result which is obtained when the composition is used.

For example, the first and second compositions may be independently selected from a cleaning composition (providing a cleaning benefit), a care composition (providing a care benefit), a conditioning composition (providing a conditioning benefit), a perfuming composition (providing a fragrance benefit), an abrasive composition (providing a scouring benefit), a corrosive composition (providing a corroding benefit), a cosmetic composition (providing a cosmetic benefit), a beauty composition (providing a beautifying benefit), a skin exfoliating composition (providing a skin exfoliating benefit), a hair removal composition (providing a hair removing benefit), a skin enhancement composition (providing a skin enhancement benefit), or an anti-bacterial composition (providing an anti-bacterial benefit).

To achieve the above benefits, the first composition generally comprises a first active ingredient dispersed in a first matrix material, and the second composition comprises a second active ingredient dispersed in a second matrix material.

The“active ingredients” are constituents which, either alone or in combination with other ingredients, impart the specified benefit to the article.

The first and second active ingredients are homecare and/or personal care active ingredients.

The homecare or personal care active ingredients may be one or more actives selected from a cleaning active, conditioning active, care active, cosmetic active, fragrance active, a corrosive active or an abrasive active.

The first and/or second active ingredient may be a cleaning active, such as a surface cleaning active (e.g. hard surface cleaning active), a fabric cleaning active, a body cleaning active, or a make-up removal active.

The first and/or second active ingredient may be a care active, such as a conditioning active (e.g. a fabric conditioning active), a softening active, a skincare active (e.g.

moisturiser or sunscreen), a medical active, an anti-corrosion active, or a polish active.

The first and/or second active ingredient may be a cosmetic active, such as a make-up colorant.

The first and/or second active ingredient may be a fragrance active, such as a perfume. The first and/or second active ingredient may be a corrosive active, such as a paint stripper.

The first and/or second active ingredient may be an abrasive active, such as particles for scouring a surface.

The first and/or second active ingredient may be a surfactant. The surfactants may be selected form the group consisting of anionic, non-ionic, cationic, amphoteric/zwitterionic surfactants and mixtures thereof. The surfactants may be present in an amount of 50 wt.% or less, 40 wt.% or less, 30 wt.% or less, 20 wt.% or less, or 10 wt.% or less, as a wt.% of the relevant layer. The surfactant may be present in an amount of 0.001 wt.% or more, 0.01 wt.% or more, 0.05 wt.% or more, or 0.1 wt.% or more of the relevant layer.

The first and/or second active ingredient may be present in its active form, i.e. the form which provides the desired activity/benefit. Alternatively, it may be present in the form of a precursor (e.g. a protected compound) which becomes active in use to provide the desired activity/benefit.

The first and/or second active ingredient may be present as dispersed compounds, or in the form of solid particles.

The first active ingredient may be present in the upper layer in an amount of, for example, 50 wt.% or less, 40 wt.% or less, 30 wt.% or less, 20 wt.% or less, or 10 wt.% or less, as a percentage of the weight of the layer.

The second active ingredient may be present in the lower layer in an amount of, for example, 50 wt.% or less, 40 wt.% or less, 30 wt.% or less, 20 wt.% or less, or 10 wt.% or less, as a percentage of the weight of the layer.

Optionally, the lower layer is substantially free of the first active ingredient, and the upper layer is substantially free of the second active ingredient. By“substantially free” we mean a small or negligible amount of the specified active ingredient is present in the layer, e.g. less than 1 wt.%, less than 0.5 wt.%, less than 0.1 wt.%, less than 0.01 wt.%, or less than 0.001 wt.% as a percentage of the weight of the layer. In this way, contact between the first and second active ingredients can be minimised or avoided. In instances in which the upper layer and lower layer are in direct contact with one another, there may be some mixing of the first and second active ingredients at the interface between the layers. In such instances, the bulk composition of the lower layer (i.e. away from the interface with the upper layer) may be substantially free of the second active ingredient, and the bulk composition of the upper layer may be substantially free of the first active ingredient. The bulk composition corresponds to the composition away from the interface between lower and upper layers. For example, the bulk composition of a layer may be that measured for a sample taken from a central portion of the layer.

The amount of the first active ingredient provided as part of the article may correspond to a unit dose of the first active ingredient. Similarly, the amount of the second active ingredient provided as part of the article may correspond to a unit dose of the second active ingredient. In other words, the article may be a single-use (disposable) article containing a unit dose of each of the first and second active ingredients. Advantageously, this simplifies use of the article by a consumer, since they can apply the article until all of the active species are consumed, without having to consult or follow detailed instructions.

Incompatible ingredients

The article of the present invention is suited to situations where the first and second active ingredients are incompatible. Therefore, optionally, the first and second active ingredients are incompatible. By“incompatible” we mean that the first and second active ingredients cannot be stored in a mixture together, either due to some interaction between the ingredients or due to the requirement for the ingredients to be stored and/or used in different chemical or physical environments.

The first and second ingredients may be incompatible because they interact with one another. For example, the first and second ingredients may interact with one another when in a mixture (e.g. in aqueous solution) at temperatures typically used for storage (e.g. at a room temperature of 25°C) in such a way that the ingredients are unsuitable for long term storage in an admixture.

The ingredients may be incompatible because they react with one another. For example: (i) the first active ingredient may degrade the second active ingredient, or vice versa; (ii) the first active ingredient and second active ingredient may react to form an inactive species; (iii) the first active ingredient and second active ingredient may react to form a short-lived active species which degrades during storage; or (iv) the first active ingredient and second active ingredient may form an active species which degrades a further component of the article. Alternatively, the ingredients may be incompatible because the first active ingredient masks the activity of the second ingredient, or vice versa.

Additionally or alternatively, the first and second ingredients may be incompatible because they require different conditions in order to be effectively stored and/or used.

For example, the first and second ingredients may have different solvent requirements (e.g. the first active ingredient is water soluble, whereas the second active ingredient is water insoluble), different pH requirements (e.g. first active ingredient must be stored in acidic conditions, whereas the second active ingredient must be stored in basic conditions), different mechanical requirements (e.g. first active ingredient is a soft particle, second active ingredient is a hard particle), different co-ingredient requirements (e.g. the first active ingredient may require the presence of a further compound which reacts with the second active ingredient).

Advantageously, isolating the incompatible ingredients from one another in separate layers improves storage stability, and facilitates more effective use of the articles.

Articles incorporating incompatible active ingredients include the following.

( i ) Protease and other proteins

Biological laundry detergents typically contain a range of different enzymes intended to break down different types of stains. In particular, proteases are commonly added to in order to remove unwanted proteinaceous stains. However, as well as breaking down unwanted proteins, proteases are also liable to degrade other enzymes in the laundry detergent itself, which complicates their use.

Thus, the present invention provides an article (preferably a laundry article) in which the first active ingredient is a protease and the second active ingredient is a protein (e.g. enzyme) other than a protease. Optionally, the article as described above may comprise an upper layer comprising a protease, and a lower layer comprising a protein, which lower layer is free of protease.

The second active ingredient may be, for example, a lipase, alpha-amylase, cellulase, peroxidase/oxidase, pectate lyase, mannanase, or mixtures thereof.

( ii ) Oppositely charged species

In multi-ingredient formulations, it is common to include species which have positive charge alongside others having negative charge. However, such species are liable to interact when stored together, which can reduce or mask the activity of the ingredients.

Thus, the present invention provides an article in which the first active ingredient is a positively charged species and the second active ingredient is a negatively charged species. For example, the first active ingredient may be a cationic surfactant, and the second active ingredient may be an anionic surfactant.

Suitable cationic surfactants include quaternary ammonium salts having the formula:

R ^a R ^b R ^c R ^d N ⁺ X- where R ^a , R ^b , R ^c , and R ^d are each C1-24 alkyl, aryl or aralkyl groups, and X is a suitable counterion such as F, Cl, Br, I or an alkyl sulfate.

Suitable anionic surfactants include alkyl sulphonates, such as alkylbenzene sulphonates, particularly linear alkylbenzene sulphonates having an alkyl chain length of Cs-C-is. The counter ion for anionic surfactants is generally an alkali metal, typically sodium, although other counter-ions for example MEA, TEA or ammonium can be used. Suitable linear alkyl benzene sulphonate surfactants include Detal LAS with an alkyl chain length of from 8 to 15, more preferably 12 to 14.

Other examples of suitable anionic surfactants include linear carbon chain sulfates, alcohol ether sulfates, alcohol sulfates, alkyl- and alkylaryl-alkyoxylated carboxylic acid, and the acid forms of these anionic surfactants. For example, the composition may comprise an alkyl polyethoxylate sulphate anionic surfactant of the formula: R0(C ₂ H ₄ 0) _X S03-M ⁺ where R is an alkyl chain having from 10 to 22 carbon atoms, saturated or unsaturated, M is a cation which makes the compound water-soluble, especially an alkali metal, ammonium or substituted ammonium cation, and x averages from 1 to 15. Preferably R is an alkyl chain having from 12 to 16 carbon atoms, M is sodium and x averages from 1 to 3, preferably x is 3; This is the anionic surfactant sodium lauryl ether sulphate (SLES). It is the sodium salt of lauryl ether sulphonic acid in which the predominantly C12 lauryl alkyl group has been ethoxylated with an average of 3 moles of ethylene oxide per mole.

(iii) Bleach + bleach-sensitive components

Bleaches, such as sodium perborate, sodium percarbonate or sodium hypochlorite, are commonly included in laundry compositions in order to boost the colour properties of treated fabric. However, such bleaches are liable to degrade other components in the composition, such as perfumes, dyes, enzymes and surfactants. This complicates or precludes the use of certain bleach-sensitive components, so that it is common to restrict the selection of these components to those known to be compatible with bleaches.

Thus, the present invention provides an article (preferably a laundry article) as described above in which the first active ingredient is a bleach and the second active ingredient is a bleach-sensitive component. Separating the bleach from other bleach-sensitive component minimises degradation of the bleach-sensitive component during storage.

The bleach may be, for example, an oxygen bleach, such as an alkali metal perborate, alkali metal percarbonate, or hydrogen peroxide, in particular sodium perborate, sodium percarbonate, or hydrogen peroxide. Alternatively, the bleach may be, a chlorine bleach, such as sodium hypochlorite.

The bleach-sensitive component contains a moiety which is sensitive to the action of an oxidant. For example, the bleach-sensitive component may be a compound containing an alcohol moiety, or unsaturated moiety (e.g. an alkene, alkyne or aryl moiety). The bleach-sensitive component may be, for example, a fragrance, a dye, an enzyme, a surfactant or a structuring agent/polymer. (iv) Acid + acid-sensitive components

In some products, it is useful to include an acid alongside an acid-sensitive component. The acid-sensitive component may be a compound whose breakdown (e.g. hydrolysis) is catalysed by the acid.

Thus, the present invention provides an article in which the first active ingredient is an acid and the second active ingredient is an acid-sensitive component. Separating the acid from the acid-sensitive component minimises degradation of the acid-sensitive component during storage.

(v) Base + base-sensitive components

In some products, it is useful to include a base alongside a base-sensitive component. The base-sensitive component may be a compound whose breakdown (e.g. hydrolysis) is catalysed by the base.

Thus, the present invention provides an article in which the first active ingredient is a base and the second active ingredient is a base-sensitive component. Separating the base from the base-sensitive component minimises degradation of the base-sensitive component during storage.

(vi) Different pH requirements

In some products, it is useful to include components whose pH requirements are incompatible. For example, it may be useful to include a component which is most or only effective at acidic pH alongside another component which is most or only effective at alkaline pH.

Thus, the present invention provides an article as described above in which the first active ingredient and the second active ingredient have different pH requirements. In such embodiments, the first and second layers may be water-soluble, and the pH of the first layer when dissolved in water is different to an equivalent mass of the second layer when dissolved in an equivalent mass of water. Matrix materials

The matrix materials suitable for use with the above active ingredients are solid. Suitable materials include gels, waxes, soaps, plastics and powders, including sintered powders and powders held together by a binder.

When the matrix material is a gel, it is sufficiently viscous to maintain its shape during storage of the homecare or personal care article. It may be a soft gel, which breaks up easily when disturbed. It may be a firm gel, which can retain its shape during handling, but can be broken up by application of greater force. In between, the gel may be elastic, but retain its shape better than a soft gel.

The first and second matrix materials used in the upper and lower layers may be the same. Alternatively, the matrix materials may be different.

For example, the matrix materials can be chosen to suit the particular active ingredients being used, to ensure the best compatibility between matrix and active ingredient.

Alternatively or additionally, the matrix materials can be chosen in order to achieve a particular delivery profile of the different active ingredients.

For example, the first matrix material used in the upper layer may be a relatively low viscosity material which is easily spread onto a surface, and the second matrix material used in the lower layer may be a relatively hard abradable material which slowly wears away as it is rubbed against a surface. This can be achieved, for example, when the first and second matrix materials are thickened gels, and a relatively smaller quantity of thickener is included in the first matrix material.

Advantageously, designing such functionality into the article helps to dictate the use of the article, increasing convenience for consumers and enabling improved compliance with optimal delivery protocols. In particular, multistep treatments can be carried out using a single article, with pre-defined quantities of active ingredients delivered according to a pre-determined protocol. The matrix material may be a gel. For example, the matrix material may be a gel comprising at least 15 wt.% of a polyamide-based thickener, as described in our co- pending application EP 16174137.6.

The present applicants have found that compositions incorporating polyamide-based thickeners at levels of at least 15 wt.% can form solid, dry self-supporting gels.

Advantageously, the formation of these solid, dry gels is relatively insensitive to the nature of the active ingredient and other components in the composition, and can tolerate, for example, both non-ionic and cationic surfactants as active ingredients. In addition to versatility in the range of ingredients which can be tolerated, gel formation can also occur over a broad pH range.

The upper limit for the amount of such polyamide-based thickener may be, for example, 60 wt.%, 50 wt.%, 40 wt.%, 35 wt.%, 30 wt.% or 25 wt.%. Preferably, the polyamide- based thickener may be incorporated in the composition at a level of 15 to 25 wt.%. For example, the polyamide-based thickener may be incorporated into the composition at between 16 to 24 wt.%, 17 to 23 wt.%, 18 to 22 wt.%, or 19 to 21 wt.%. Advantageously, the applicants have found that thickener incorporated in an amount of 20 wt.% leads to formation of gels which show particularly good mechanical properties. In particular, the gels may be solid and dry.

The polyamide-based thickener may be an end-capped polyamide, such as a

polyaklyleneoxy-terminated polyamide thickener.

The polyalkyleneoxy-terminated polyamide thickener may comprise or consist of a block copolymer of the formula hydrocarbon-polyalkyleneoxy-polyamide- polyalkyleneoxy- hydrocarbon. The“polyalkyleneoxy” group is a polyether group based on repeated alkyleneoxy units, such as -CH2CH2O-, -CH ₂ CH ₂ (CH ₃ )0-. The block copolymer may have the following formula:

wherein, independently at each occurrence, R ¹ is selected from C1-22 hydrocarbon radicals; R ² is selected from C2-6 alkylene diradicals; R ³ is selected from C2-52

hydrocarbon diradicals (preferably where at least 50 mol% of the R ³ radicals have at least 34 carbons); R ⁴ is selected from C2-36 hydrocarbon diradicals and C4-100 polyether diradicals; Z is selected from O and NH; x is an integer from 2 to 100; y is an integer from 1 to 10; and z is an integer from 2 to 100.

The term“hydrocarbon group” is intended to refer to groups containing only carbon and hydrogen atoms. Suitable hydrocarbon groups are formed from one or more of aliphatic and aromatic moieties. Suitable aliphatic moieties are alkyl, alkylene, alkenyl, alkenylene, alkynyl, alkynylene, cylocalkyl, cycloalkylene, cycloalkenyl, cycloalkenylene, cycloalkynyl, and cycloalkynylene moieties. Exemplary alkyl moieties are methyl, ethyl, propyl, hexyl, and 2-ethylhexyl; while exemplary alkylene groups are monoradials such as methylidene (=CH ₂ ) and diradicals such as methylene (-CH2-), and ethylene (-CH2CH2-). Suitable aromatic moieties include, for example, phenyl, and naphthyl, and combinations thereof such as biphenyl. The hydrocarbon groups may be a combination of aromatic and aliphatic groups, such as benzyl, tolyl or xylyl.

The R ¹ groups may be alkyl, such as C1-12 alkyl, in particular C1-4 alkyl. Optionally, each R ¹ group is methyl.

The R ² groups are C2-6 alkylene, in particular C2-4 alkylene. Optionally, each R ² group is - CH2CH(R ^2a )- wherein R ^2a is selected from hydrogen, methyl and ethyl.

The R ³ groups may have at least 30 carbons, such as 30-42 carbons. Preferably, at least 50 mol% of the R ³ groups are C34 groups. For example, C34 groups may constitute at least 60 mol%, at least 70 mol%, at least 80 mol%, at least 90 mol% or at least 95 mol% of the R ³ groups. The R ⁴ groups may be hydrocarbon groups having, for example, 1-20 carbons, in particular 1-10 carbons. For example, the R ⁴ groups may be C1-20 alkylene groups, C _MO alkylene groups, or C2-6 alkylene groups. Optionally, at least 50% of the R ⁴ groups have 2 carbons. Preferably, the R ⁴ groups are ethylene groups (-CH2CH2-).

Alternatively, the R ⁴ groups may be polyether groups, i.e. groups having blocks containing the repeating formula -O-R ² -, where R ² is as defined above.

Optionally, the block copolymer may have R ¹ selected from C1-12 alkyl; R ² selected from C2-6 alkylene, R ³ selected from C30-42 hydrocarbon groups where at least 50 mol% are C34 groups; and R ⁴ selected from C1-20 alkylene groups.

Optionally, the block copolymer may have R ¹ selected from C1-4 alkyl; R ² selected from -CH2CH (R ^2a )- where R ^2a is hydrogen, methyl or ethyl; R ³ selected from C30-42 hydrocarbon groups where at least 50 mol% are C34 groups; and R ⁴ groups which are -CH2CH2-.

The above block copolymers may be made by reacting together reactants comprising dimer acid, diamine, and a polyether having both hydrocarbon termination and

termination selected from amine, hydroxyl and carboxyl, according to the methods discussed in WO 02/059181.

The polyamide-based thickener may have a weight average molecular weight (M _w ) of greater than 10,000, greater than 12,000, greater than 15,000; greater than 17,000, greater than 18,000, or greater than 18,500. The upper limit for the weight average molecular weight may be, for example, 25,000; 24,000; 23,000; 22,000; 21 ,000 or 20,000. For example, the weight average molecular weight may be 15,000 to 25,000; 17,000 to 23,000; 18,000 to 22,000; 18,000 to 21 ,000; or 18, 000 to 20,000; or 18, 500 to 20,000. Weight average molecular weights within these ranges are preferred, since the resulting gels are found to be dry and have good mechanical properties with comparatively low sensitivity to the other components and pH of the gel.

A particularly good balance of properties is observed for polyalkyleneoxy-terminated polyamide polymers having a M _w of -19,000, and hence ranges of 17,000 to 23,000; 18,000 to 22,000 and, in particular 18,500 to 20,000 are preferred. In particular, polymers having this range of molecular weights produced solid gels which displayed particularly good dryness, making them suitable for attaching to surfaces. These advantageous properties allow the gel compositions formed from polymers having this molecular weight range to be used in a variety of practical applications.

The weight average molecular weight is measured by preparing a solution of the copolymer or composition in a suitable solvent, e. g., tetrahydrofuran (THF) and identifying the retention time of the copolymer by gel permeation chromatography, and comparing that retention time to the retention times of solutions of polystyrene having known molecular weight characterizations.

The polyamide-based thickener may have a softening point of 50°C to 150°C, preferably 75°C to 125°C, more preferably 80°C to 100°C, most preferably 90°C to 100°C. The softening point may be determined by a Ring and Ball method, such as ISO 4625.

The polyamide-based thickener may have an acid number of less than 25, less than 20, preferably less than 15, more preferably less than 10. The skilled reader understands that the acid number corresponds to the mass of potassium hydroxide in milligrams required to neutralise one gram of the polyamide-based thickener. In instances where the polyamide-based thickener comprises a polyalkylkeneoxy-terminated polyamide copolymer of the formhydrocarbon-polyether-polyamide-polyether-hydrocarbon, the copolymer does not have any free carboxylic acid groups, and accordingly has an acid number of zero. However, when prepared from diacid, diamine and hydrocarbon- terminated polyether, some of the diacid may not react with the diamine and/or polyether, and accordingly the final product may have some unreacted carboxylic acid that will be responsible for the final product having an acid number greater than zero. Preferably, the product has a minor amount of this unreacted diacid, and thus only a small acid number. Esterification catalysts may be used to encourage all of the diacid to react with hydroxyl groups, so as to minimise the amount of free acid.

The polyamide-based thickener may have an amine number of less than 25, less than 20, less than 15, less than 10, less than 5, less than 3, less than 2 or less than 1. The skilled reader understands that the amine number is determined by titration of amine acetate from the polyamide thickener by a dilute, typically 1 N, HCI solution, and is calculated according to (A x N x 56.1 )/g sample, where A is ml. of HCI titrant consumed, N is the normality of HCI titrant and g is the sample weight in grams. In instances where the polyamide-based thickener comprises a polyalkylkeneoxy-terminated polyamide copolymer of the form hydrocarbon-polyether-polyamide-polyether-hydrocarbon, the copolymer does not have any free amine groups, and accordingly has an acid number of zero. However, when prepared from diacid, diamine and hydrocarbon-terminated polyether, some of the diamine may not react with the diacid and/or polyether, and accordingly the final product may have some unreacted amine groups that will be responsible for the final product having an amine number greater than zero. Preferably, the product has a minor amount of this unreacted diamine, and thus only a small amine number. Amidification catalysts may be used to encourage all of the diamine to react with carboxyl groups, so as to minimise the amount of free amine.

Optionally, the polyamide-based thickener is a polyalkyleneoxy-terminated polyamide thickener having a weight average molecular weight of 15,000 to 25,000, and a softening point of 75°C to 125°C. Preferably, the polyamide-based thickener is a polyalkyleneoxy- terminated polyamide thickener having a weight average molecular weight of 18,500 to 20,000, and a softening point of 80°C to 100°C. Thickeners having these properties were found to produce gels with particularly good properties with comparatively low sensitivity to the other components and pH of the gel. A particularly preferred polyalkyleneoxy- terminated polyamide thickener is Crystasense HP5, marketed by Croda.

Advantageously, polyalkyleneoxy-terminated polyamide thickeners, such as Crystasense HP5, may be water soluble.

The skilled reader is familiar with methods for depositing the gels, and other matrix materials. For example, the gels can be either be spread or dropped onto a surface, and allowed to set on the substrate.

Article forms

The article may be provided in a packaging material. For example, the article may be provided in a packet or container formed from, e.g. plastic, metal, paper or cardboard. Thus, the present invention also includes a product comprising an article as described above in a packaging material.

The article of the present invention may be a homecare article. By“homecare article” we mean an article intended for the treatment (including cleaning, caring or conditioning) of the home or any of its contents. For example, the article may be used for treating hard surfaces in the home, cleaning items such as dishes or other kitchen hardware, conditioning the atmosphere of the home (e.g. an air freshener), or may be used in laundry applications.

The article of the present invention may be a personal care article. By“personal care article” we mean an article intended for the treatment, cleaning, caring or conditioning of a person, for example for personal hygiene or beautification. For example, the article may be used for cleaning or conditioning the skin, hair or oral cavity, for applying or removing make-up, or applying deodorant or antiperspirant.

The article may be a surface-treating article, such as a hard-surface treating article.

The article may be a cleaning article, such as a surface-cleaning article, in particular a hard surface-cleaning article.

The article may be a surface-care article.

The article may be a surface-conditioning article, such as a skin-conditioning article.

Methods of production and use

In a further aspect, the present invention provides methods of producing an article of the present invention, comprising adding a lower layer to a substrate, and subsequently adding an upper layer at least partially overlaying the lower layer, wherein the substrate, lower layer and upper layer are as defined above.

For example, the methods may involve forming a first gel composition comprising a first active ingredient and a thickener, applying the first gel composition to an area on a substrate, and allowing the gel composition to solidify to form the lower layer; forming a second gel composition comprising a second active ingredient and a thickener, applying the second gel composition so as to at least partially overlay the lower layer, and allowing the gel composition to solidify to form the upper layer.

The present invention also relates to methods of using an article of the present invention.

For example, a further aspect provides a method of treating an area using the article of the first aspect of the invention, comprising rubbing the upper layer of the article against the area to provide the first homecare or personal care benefit, continuing to rub the upper layer so that it gradually erodes to expose the underlying lower layer, and rubbing the lower layer of the article against the area to provide the second homecare or personal care benefit. The method may optionally involve activating the upper and/or lower layers before use. Such activation may involve, for example, immersing the article in water before use.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of our proposals are now described with reference to the accompanying drawings, in which:

Figure 1 A is a perspective view of an article according to the present invention, taking the form of a wipe having planar layers of erodible material;

Figure 1 B is a cross-section through the dotted line shown in Figure 1A;

Figure 2A is a perspective view of an article according to the present invention, taking the form of a wipe having dome-shaped layers of erodible material, including a protective membrane to separate active ingredients; and

Figure 2B is a cross-section through the dotted line shown in Figure 2A.

DETAILED DESCRIPTION

Figures 1 A and 1 B show surface treatment wipe 1 , having gel layers 3 and 5 provided on a flexible plastic sheet 7. The wipe is formed by depositing the lower gel layer 3 onto the plastic sheet 7, and then depositing upper gel layer 5 onto lower gel layer 3 so that it completely overlays the lower gel layer 3. Upper gel layer 5 is an elastic, water-soluble gel having a bleach-containing cleaning composition dispersed throughout. Lower gel layer 3 is a relatively firmer gel (due to the incorporation of a greater quantity of thickening agent) containing a surface care composition, containing a polish and fragrance. The fragrance in lower gel layer 3 is degraded by the bleach in upper gel layer 5, and thus the separation of these components into different gel layers helps to limit degradation of the fragrance during storage.

The wipe is specifically designed to treat a bathroom sink bowl. In this case, to treat the sink, the consumer pre-wets the surface of the sink, picks up the plastic sheet and repeatedly rubs the upper gel layer 5 against the surface so that the relatively soft gel layer is spread across the surface, and dissolves in the water. Through doing this, the consumer carries out a first cleaning step using the bleach. The consumer does not need to handle the bleach directly, and the consumer’s hands are protected from contacting the bleach by the plastic sheet. As the consumer continues to rub the wipe against the surface, lower gel layer 3 is exposed. The relatively firmer lower gel layer 3 then comes into contact with the surface and is worn away gradually (i.e. abraded) to deliver the polish and fragrance to the surface, until the consumer is happy with the overall finish.

The amounts of active ingredients in both layers correspond to a unit dose for treatment of a standard bathroom sink bowl, to achieve optimal treatment without significant wastage of materials. Once the application is complete, the consumer disposes of the wipe, optionally folding the plastic sheet 7 over the regions which contained the gel layers to prevent any remnants of the layers transferring to other waste/trash.

Figures 2A and 2B show an alternative surface treatment wipe 11 , having gel layers 13 and 15 separated by a protective membrane 19, provided on a flexible fabric 17. The wipe has been formed by placing a drop of thickened-liquid gel on the cloth 17 and allowing it to set to form solid lower gel layer 13, subsequently coating with a further gel to form the protective membrane 19, and finally coating with a gel to form the upper gel layer 15. In this way, the layers are dome-shaped. The upper and lower gel layers contain respectively a cleaning composition and surface care composition, as described above in relation to Figures 1A and 1 B. However, in this case, the compositions are separated from one another by protective membrane 19, which prevents mixing of the compositions and hence avoids degradation of the fragrance by the bleach during storage. The protective membrane is made from the same gel composition as the upper layer 15 but lacks any active ingredients. The protective membrane spreads across a surface to expose the lower layer 13 when applied by a consumer, in the process described above in relation to Figures 1A and 1 B. EXAMPLES

Experiments were carried out to demonstrate the production and use of an article according to the present invention.

In this case, the article was a toilet cleaning wipe, consisting of a waterproof sheet (serving as a substrate) having an array of discrete cleaning features present. Each cleaning feature consisted of a multilayer structure having the following layers:

^(a) Rheology modifier was Crystasense HP5 (Croda)

^(b) Neodol 91-8 (Shell), which corresponds to ethoxylated C9-11 alcohols having -69-7% EO groups, EO/OH 8.3, M _w of 524 and HLB of 13.9.

^(c) pH was adjusted using citric acid or sodium hydroxide.

^(d) PEG-12 dimethicone

The multilayer structures were built up by depositing the bottom layer on the sheet, and then subsequently adding the middle and top layers. The bottom and middle layers were prepared by adding a commercially available polyamide-based thickener (Crystasense HP5, from Croda - a polymer having a M _w -19,000, softening point of 93°C, acid number of less than 15 and amine number of less than 3) to an aqueous solution containing the other ingredients. The bottom and middle layers were formed by: 1. melting pastilles of the thickener at 95°C;

2. heating the water to 70°C;

3. adding the remaining components to the water and stirring for 1-2 minutes at 150- 300 rpm using a Heidolph RZR 1 overhead stirrer, to create a uniformly dispersed aqueous composition;

4. slowly adding the molten thickener to the aqueous composition and stirring for 5 minutes until fully dispersed and uniform;

5. depositing a layer of the molten thickener; and

6. cooling the composition to produce a solid gel.

To form the top layer, a commercially available limescale removing gel was heated and deposited on top of the middle layer, before allowing the gel to cool. The top layer remained as a relatively soft self-supporting gel.

The resulting wipe was tested. It was found that rubbing the cleaning features onto a surface led the top, middle and bottom layers to be spread in sequence onto the surface. The layers were sufficiently robust to maintain their shape before application, but were capable of being spread onto the surface by hand without requiring excessive force to be applied. The sequential delivery was evident from the change in fragrance over the course of application, with the initial fragrance from the top layer gradually being replaced by the fragrance from the bottom layer. Through use of the wipe in this way, it was possible to achieve a limescale removing benefit, followed by cleaning and surface conditioning benefits (gloss and fragrance) through the simple repeated rubbing motion of the wipe across the toilet surface.