FR3122088A1 - COLOR CHANGING COMPOSITION IN AQUEOUS GEL FORM - Google Patents

Abstract

The present invention relates to a color-changing composition in the form of an aqueous gel comprising, at least: a) an aqueous phase; b) microcapsules containing releasable dye(s), said microcapsules comprising: - a core comprising an organic material, - at least one layered coating surrounding said core, the layered coating comprising at least one polymer, at least at least one colorant, and preferably at least one lipid-based material; c) a salicylic acid compound and/or a derivative thereof; d) a hydrophilic gelling agent; and e) an alcohol chosen from a monoalcohol and a polyol. Figure for abstract: Figure 1

Description

COLOR CHANGING COMPOSITION IN AQUEOUS GEL FORM

The present invention relates to a color-changing composition in the form of an aqueous gel which is particularly useful for the care, hygiene and/or makeup of keratinous materials.

In particular, a color-changing composition according to the invention can be any type of cosmetic composition such as a foundation, a lip balm, a gloss, an eyeliner, a mascara, an eye cream, a eye care cream, eye make-up product, body make-up product, skin coloring product, care product such as care cream, "BB" product (Blemish Balm product capable of covering imperfections), a tinted product and/or a sunscreen product. The coloring composition according to the invention can be liquid, semi-solid or solid.

A composition of the invention is in particular a composition intended to be applied to a keratinous material, in particular the skin and more particularly the skin of the face.

Cosmetic compositions, in particular foundations, are commonly used to give the skin an aesthetic color, but also to mask skin imperfections such as redness and/or marks. In this regard, many formulations have been developed to date.

In this regard, there is a growing interest in cosmetic products that allow color change in response to external stimuli such as shear force for example.

Generally, this objective is achieved by including in the cosmetic composition microencapsulated colorants in which, when applied to the skin, the composition provides the expected color change. More particularly, the color change is ensured by the microcapsules containing the dye which, when they rupture under the effect of a mechanical force, release the dye trapped in the composition, thus changing its color. A mechanical action such as friction makes it possible to spread the topical composition and facilitates its penetration into the skin. The immediate color change of the composition produces a visual aesthetic effect. As these microcapsules have the ability to swell or soften on contact with an aqueous phase, they are generally advantageously deformable when they are applied to a keratinous material and thus provide a feeling of softness to the user. They are also usually soft enough to break on very light rubbing or pressure on the skin to release their contents but, nevertheless, they are strong enough to prevent destruction of the coating during manufacture, even at during an industrial process, and storing the corresponding color-changing composition.

Different types of trapped dyes and more particularly microcapsules containing pigments are already available. They differ mainly by the type of trapping material(s) and/or the type of encapsulation. The present invention relates more particularly to microcapsules containing releasable dye(s), said microcapsules comprising:

- a core comprising an organic material,

- at least one stratified coating surrounding said core, and comprising at least one polymer, at least one colorant, and advantageously at least one lipid-based material.

These microcapsules containing releasable dye(s) are of particular interest because they mask the original color of the encapsulated dyes, increase the stability of these dyes against degradation and prevent the unwanted release of the encapsulated dyes in the composition. during the manufacturing process and prolonged storage.

Compositions comprising microencapsulated dyes similar to those used in the present invention are known in practice in the form of emulsions, in particular in the documents WO2014136060 and WO2014136061. However, when they are formulated in compositions of aqueous gels, said microencapsulated colorants do not provide a feeling of softness to the user, and therefore do not meet consumer expectations in terms of cosmetic products. Indeed, when they are formulated in aqueous gel compositions, the microcapsules provide a feeling of discomfort on application, giving the user a sensation of "rubbing", resulting mainly from the fact that the outer layer of the microcapsules is not softened enough. It also results in an absence or defect in the release of color, for example a defect in the release and diffusion of the pigments of the microcapsules on the skin, resulting from the inability of the microcapsules to break or rupture during application.

With regard to aqueous gels, it therefore remains necessary to provide compositions allowing good diffusion of the color on application, while preserving the stability of the microcapsules and good sensoriality on the skin.

It is therefore still necessary to have aqueous gels that allow good color release on application.

It remains in particular to have aqueous gels in which the force capable of obtaining the rupture of the microcapsules is the minimum conventional force necessary to apply or spread a cosmetic composition on the skin.

There is also still a need to provide a neat-looking composition that offers good makeup effects, in particular a good covering effect.

At the same time, there is a need to provide microcapsules containing dyes, which retain good burst strength and have better resistance to flow. It is also necessary to provide a cosmetic composition in which the microcapsules are or are not visible in the mass of the composition depending on the desired appearance.

There is also a need to provide a cosmetic composition that allows adjustment of the preferred coloration or gradation pattern by varying the method or intensity of application to the skin or the use of microcapsules containing different colorants.

It is also necessary to provide a stable cosmetic composition with a large panel of associated solvents/ingredients.

It is also necessary to provide a cosmetic composition containing microcapsules of encapsulated pigments which do not cause a feeling of discomfort to the user during application.

It is also necessary to provide a cosmetic composition containing microcapsules of encapsulated pigments which disintegrate rapidly, even immediately, upon application, with a liquid sensation on the skin and leading to colored compositions devoid of any grainy appearance. In particular, the composition can have different shades or gradations of colors depending on the frictional force.

There is also a need to provide encapsulated pigment microcapsules having sufficient hardness to be mixed in an industrial process without alteration. Advantageously, the hardness of the microcapsules does not decrease significantly during the preparation process.

In particular, the technical problem underlying the present invention, namely obtaining aqueous gels comprising microcapsules containing releasable dye(s), has been solved by using the specific combination of microcapsules containing releasable dye(s) with salicylic acid or derivatives thereof.

The use of salicylic acid and derivatives thereof in topical compositions, in particular cosmetic or dermatological, for example as a keratolytic agent for the treatment of acne or as an anti-aging agent, is a known practice. Documents FR-A-2 581 542 and EP-A-378 936 describe these derivatives. Nevertheless, salicylic acid or derivatives thereof have never been reported in combination with microencapsulated dyes such as those mentioned above, in aqueous gel compositions.

Surprisingly and advantageously, the compositions according to the invention meet the needs of the prior art.

Thus, according to one of its aspects, the subject of the invention is a color-changing composition for caring for and/or making up keratinous materials in the form of an aqueous gel comprising, at least:

a) an aqueous phase;

b) microcapsules containing releasable dye(s), said microcapsules comprising:

- a core comprising organic matter,

- at least one laminated coating surrounding said core, the laminated coating comprising at least one polymer, at least one colorant, and advantageously at least one lipid-based material;

c) a salicylic acid compound and/or a derivative thereof;

d) a hydrophilic gelling agent chosen from synthetic polymeric gelling agents, natural or naturally occurring polymeric gelling agents, mixed silicates and fumed silicas, and mixtures thereof; and

e) selected from ethanol, propanol, butanol, isopropanol and isobutanol.

Preferably, the viscosity of the gel according to the invention is greater than or equal to 20UD (Mobile 3) by Rheomat at 25°C. The viscosity is generally measured at 25°C with a RHEOMAT RM 180 viscometer with spindle 3 adapted to the viscosity of the product to be tested (the spindle is chosen to have a measurement between 10 and 150 for the unit of difference UD), the measurement being made after 10 min of rotation of the mobile inside the composition, with a shear of 200 s ^-1 . The UD values can then be converted into Poise (1 Poise= 0.1 Pa.s) using a look-up table.

More preferably, the composition contains a gelled aqueous phase.

The microcapsules used according to the present invention are breakable when spreading the aqueous gel composition on the skin. The friction or pressure of the aqueous gel on the skin allows the release of the contents of the microcapsules.

The aqueous gels according to the present invention are particularly stable, in particular for 2 months at ambient temperature and even at 37° C. or 45° C., and they exhibit optimal cosmetic properties. Indeed, the aqueous gels according to the present invention have an appropriate fluidity: they are easy to handle and furthermore easy to apply and to spread on the skin. In addition, the inventors have noticed that the aqueous gels according to the invention remain without color release.

These aqueous gels also have a texture required for cosmetic use: they are not sticky and are soft to the touch.

In general, the microcapsules used according to the invention have an average particle size ranging up to about 800 μm in diameter. Preferably, the average particle size is less than about 400 µm in diameter of the dye microcapsules for skin care applications. Preferably, the average size of the particles will be from 10 μm to 800 μm, advantageously from 40 μm to 800 μm, in particular from 50 μm to 600 μm, in particular from 50 μm to 400 μm in diameter.

According to a preferred embodiment, the average particle size is in the range from about 40 µm to 400 µm in diameter, preferably from about 50 µm to 300 µm in diameter, in particular from 60 µm to 250 µm in diameter. diameter and more preferably about 80 µm to 200 µm in diameter.

Preferably, the microcapsules containing releasable dye(s) are multilayered microcapsules

Preferably, the microcapsules containing releasable dye(s) are multilayer microcapsules containing releasable dye(s), said microcapsules comprising:

- an uncolored core consisting of organic matter, and

- a multilayer coating surrounding said core and comprising at least one internal organic layer and an external organic layer of different color and respectively trapping at least one dye.

Preferably, the microcapsules comprise at least two layers, preferably at least one colored organic internal layer and an organic external layer of different color.

Preferably, the core comprises at least one monosaccharide or its derivatives such as said organic material, in particular a monosaccharide-polyol advantageously chosen from mannitol, erythritol, xylitol, sorbitol and mixtures thereof, preferably mannitol.

The stratified coating surrounding said core advantageously comprises at least one (several) hydrophilic polymer(s) chosen from the group consisting of polysaccharides and derivatives, preferably those including a type of ose or several types of monosaccharide, preferably several types of monosaccharide comprising at least D-glucose units, in particular starch and its derivatives, cellulose or its derivatives, and more preferably starch and its derivatives.

Preferably, the microcapsules include at least one lipid-based material, preferably with amphiphilic properties such as lecithins and in particular hydrogenated lecithin.

The core advantageously represents from 1% to 50% by weight, preferably from 5 to 30% by weight, and in particular from 10 to 20% by weight relative to the total weight of the microcapsule.

Advantageously, the dye(s) represent(s) from 20 to 90%, preferably from 30 to 80%; in particular from 50 to 75% by weight with respect to the microcapsule.

In particular, the microcapsules comprise at least:

- an inner core of monosaccharide-polyol, preferably mannitol,

- at least two layers of different colors,

- at least one hydrophilic polymer preferably chosen from polysaccharides or their derivatives, and more preferably from starch or its derivatives,

and advantageously at least one lipid-based material, preferably an amphiphilic compound, more preferably a phospholipid, and more preferably a phosphoacylglycerol such as hydrogenated lecithin.

Preferably, the microcapsules containing releasable dye(s) are multilayer microcapsules containing releasable dye(s), said microcapsules comprising:

- an uncolored core consisting of an organic material, and

- a multilayer coating surrounding said core and comprising at least one internal organic layer and an external organic layer of different color and respectively trapping at least one dye.

According to one embodiment, each layer of the microcapsule contains at least one specific dye or a specific mixture of dye(s).

According to another embodiment, the outer layer of the microcapsule contains at least one specific dye or a specific mixture of dye(s).

The dyes are in particular pigments, preferably chosen from the group consisting of metal oxides.

According to one embodiment, a layer of the microcapsule contains iron oxides and titanium dioxide (TiO ₂ ) as colorants.

According to one embodiment, a layer of the microcapsule contains only titanium dioxide (TiO ₂ ) as colorant.

The composition may comprise at least from 0.1% to 25% by weight, preferably from 0.5% to 15% by weight and in particular between 1 and 10% by weight of microcapsules relative to the weight of the composition.

The composition according to the invention may also comprise from 0.1 to 70% by weight, relative to the weight of the composition, of one or more additional cosmetic ingredient(s) chosen among volatile and non-volatile silicone or hydrocarbon oils, surfactants, fillers, additional gelling agents, thickening agents, film-forming agents, polymers, preservatives, silicone elastomer, self-tanning agents, non-trapped additional colorants, cosmetic actives, pH regulators, fragrances, UV filters and mixtures thereof.

The microcapsules inside the composition are advantageously breakable under pressure during application to keratinous materials.

The present invention also relates to a cosmetic process for caring for and/or making up keratinous materials, comprising the application to said keratinous materials, in particular to the skin, of a composition according to the invention.

The expression “physiologically acceptable medium” is intended to designate a medium which is particularly suitable for the application of a product of the invention to keratinous materials, in particular the skin and more particularly the skin of the face.

The word "capsule" is also used to refer to a "microcapsule".

For the purposes of the present invention, the term “keratinous material” is intended to cover the skin, the mucous membranes such as the lips, the nails and the eyelashes. The skin and the lips, in particular the skin of the face, are more particularly considered according to the invention.

As emerges from the examples which follow, the compositions in accordance with the invention prove to be advantageous in several respects.

Encapsulation of colorants prevents unwanted re-agglomeration of pigments during manufacture and prolonged storage of cosmetic compositions.

As the microcapsules of the compositions of the invention have the ability to swell or soften on contact with an aqueous phase as defined below, they are advantageously deformable when they are applied to a keratinous material and thus provide a feeling softness to the user. In addition, their small size contributes to not creating discomfort or an unfavorable, grainy feeling during application.

However, the microcapsules of the compositions of the invention are soft enough to break upon very slight friction or pressure on the skin in order to release their contents, but they are nevertheless sufficiently durable to avoid the destruction of the coating during of manufacture, even during an industrial process, and the storage of the corresponding color-changing composition.

Furthermore, the microcapsule of the invention allows the use of ordinary equipment for the preparation of the compositions of the invention because no staining of the device occurs during the manufacturing process.

Accordingly, the microcapsules of the present invention are of particular value because they mask the original color of the encapsulated dyes, increase the stability of these dyes against degradation, and prevent the unwanted release of the encapsulated dyes in the composition of the invention during the process of manufacture and prolonged storage.

Finally, the compositions of the invention also have the advantage of meeting consumer expectations in terms of cosmetic products.

According to another of its aspects, an object of the present invention also targets a cosmetic process comprising at least the steps consisting in applying at least part of a composition according to the invention to the surface of a keratinous material, in particular the skin.

According to the invention, the “color-changing composition” designates a composition in which the color before application is different from the color after application, this difference being visible to the naked eye.

In particular, this color-changing composition can be related to a color difference value ∆E in the CIE Lab 1976 system (∆E before/after application).

The ∆E is defined by the equation:

:

in which L ₁ , a ₁ , b ₁ are the parameters in the colorimetric space of the 1 ^st color (composition before application) and L ₂ , a ₂ , b ₂ those of the 2 ^nd color (composition after application and homogenization on keratinous material).

These values can be measured by spectrophotometer or with a chromosphere (for the composition applied to the skin).

The color-changing composition according to the invention can be characterized as having a ∆E before/after application greater than 1, in particular greater than or equal to 2, preferably greater than or equal to 3.

MICROCAPSULES CONTAINING A (OF THE) DYE ( S ) RELEASABLE ( S )

The term "microcapsule", as used herein, means a spherical microcapsule containing at least one layered coating trapping at least one colorant and surrounding a core chemically different from the coating. Microcapsules are distinguished from microspheres, which consist of a homogeneous spherical matrix.

According to one embodiment, the "at least one stratified coating" is a multilayer coating, preferably an organic multilayer coating.

The term "multi-layered microcapsule" refers to a microcapsule consisting of a core surrounded by a coating according to one or more inner layers and an outer layer. The one or more inner layers forming the multilayer coating of the multilayered microcapsule and the single outer layer of the microcapsule may consist of the same or different wall-forming organic compound(s). .

The microcapsule according to the invention comprises a core also called “inner core” surrounded by a coating based on one or more layers. In a preferred embodiment, the microcapsule is a “multilayer” microcapsule, comprising at least an inner layer and an outer layer. The one or more inner layers forming the multilayer coating of the multilayered microcapsule and the single outer layer of the microcapsule may consist of the same or different wall-forming organic compound(s). .

In a particular embodiment, the inner layer and the outer layer are formed of the same organic compounds forming a wall, the core is then surrounded by a one-layer coating.

In one embodiment, the outer layer contains no colorant. In another embodiment, the outer layer includes at least one colorant.

The term "wall-forming organic compound" means an organic compound or a combination of two or more different organic compounds, as defined herein, which form a component of the layer(s) of the microcapsules. In a preferred embodiment, the "wall-forming organic compound" comprises at least one polymer.

The term "dye" refers to organic pigments such as synthetic or natural dyes chosen from the well-known FD&C or D&C dyes, inorganic pigments such as metal oxides or lakes, as well as any combination (mixture) of these. Accordingly, the dye useful according to the present invention may be oil soluble or dispersible or have limited water solubility.

In preferred embodiments, the colorant is an inorganic pigment, more preferably a metal oxide.

In particular, the average particle size can be 50 to 1000 mesh (about 400 µm to 10 µm), especially 60 to 200 mesh (about 250 µm to 75 µm) as measured by the sieve test method or observed under a microscope.

Preferably, a composition according to the invention may comprise from 0.1% to 25% by weight and preferably from 0.5% to 15% by weight and in particular between 1 and 10% by weight of microcapsules relative to the total weight of said composition.

In particular for a skin care composition according to the invention, the amount of microcapsules will be in a range from 0.1% to 10%, preferably from 0.2% to 5% by weight based on the weight composition total.

In particular for a makeup composition according to the invention, the quantity of microcapsules will be in a range ranging from 0.5% to 25%, preferably from 1% to 15% by weight relative to the total weight of the composition.

The microcapsules will be integrated into the cosmetic formula generally at the last stages of the formulation and after any filtration steps, in order to prevent the microcapsules from being broken. Preferably, the microcapsules according to the inventions are added and uniformly mixed at temperatures below 50°C. They are gently mixed using a paddle rather than a homogenizer.

The microcapsules can be produced by several methods known to those skilled in the art in the field of coating or encapsulation, including pelleting, granulation, coating, etc. For example, the microcapsules can be obtained by a process comprising mixing the compounds (actives, pigments, polymers, solvents) and drying to form capsules as indicated in documents WO01/35933 and WO2011/027960, or a process comprising granulation and coating by spray drying as indicated in document FR2841155, or by fluidized bed technology, which has long been used in the food and pharmaceutical industry for the coating and encapsulation of ingredients. By way of example, mention may be made of WO2008/139053, which relates to the preparation of multilayer spheroid capsules comprising a sugar core and concentric layers of pharmaceutical active ingredients. The fixing of the pharmaceutical active ingredients on the core is carried out by impregnation, spraying or projection, then the first layer is dried before the application of a second.

The fluidized bed process is described for example in Teunou et al. (Fluid-Bed Coating, Poncelet, 2005, D. Food Science and Technology (Boca Raton, FL, USA) , volume 146, issue devoted to encapsulated and powdered foods, pages 197 to 212). A particularity of the fluidized bed process is that it leads to coated particles in which the core is well encapsulated, compared to spray drying, which leads to a matrix whose core material is randomly dispersed in a polymer.

In a preferred embodiment, the microcapsules are obtained by the fluidized bed process.

According to this embodiment, preferably at least one layer of the microcapsules is obtained by the fluidized bed process.

In a particular embodiment, the outer layer is obtained by the fluidized bed process.

In another particular embodiment, at least one internal layer is obtained by the fluidized bed process.

Preferably, all the layers are obtained by the fluidized bed process.

A person skilled in the art knows how to adjust the quantity of air, of liquid and the temperature making it possible to reproduce a capsule according to the invention.

Preferably, a fluidized bed process implemented according to the invention includes the Würster process and/or the tangential spray process. Such a process allows, unlike a pelleting process, to prepare spherical capsules with a core surrounded by one or more circumferential layers.

When the entire process for preparing the layers surrounding the core of the microcapsules according to the invention is carried out by a fluidized bed process, the layers of microcapsules are advantageously regular, concentric and have a uniform thickness.

Various examples of the preparation of capsules according to the invention will be given later in this description.

I a) Core

The core is made of at least one organic material. The size of said nucleus preferably ranges from 500 nm to 150 μm in diameter.

Preferably, the core is in solid and/or crystalline form at ambient temperature.

In a particular embodiment, the organic material is chosen from organic materials having a high capacity for dissolving in water. Preferably, the core is water soluble or water dispersible.

In a particular embodiment, the core is colorless, that is to say that it contains no coloring matter.

In a particular embodiment, the core is based on a single compound. This compound is organic and more preferably is a natural compound.

According to a preferred embodiment, the core consists of sugar-alcohol, preferably a monosaccharide-polyol advantageously chosen from mannitol, erythritol, xylitol, sorbitol.

In a particular embodiment, the core consists of mannitol and, more preferably, exclusively of mannitol.

According to an alternative embodiment, the core contains at least mannitol and at least one additional ingredient, preferably a polymer chosen from hydrophilic polymers. In particular, such a core can comprise mannitol and hydrophilic polymers chosen from cellulose polymers, starch polymers and their mixture, preferably their mixture.

In a preferred embodiment, the cellulose polymer is a carboxymethylcellulose and the starch polymer is an unmodified natural starch, for example corn starch.

The nucleus can be constituted by a seed (or a crystal) of one of the preceding materials.

The core is preferably contained in an amount of 1% to 50% by weight, preferably 4 to 40% by weight, in particular 5 to 30% by weight, and in particular 10 to 20% by weight relative to the total weight of the microcapsule.

The mannitol is preferably contained in an amount of 2% to 100% by weight, preferably 5 to 100% by weight, and in particular 100% by weight relative to the total weight of the core.

The mannitol is preferably contained in an amount of 1% to 50% by weight, preferably 4% to 40% by weight, in particular 5% to 30% by weight, and in particular 10% to 20% by weight. weight relative to the total weight of the microcapsule.

I b) Outer layer(s) or coating

As indicated above, the core is advantageously surrounded by a coating, or an outer layer(s) preferably comprising at least an inner layer and an outer layer. In the latter case, these layers preferably extend concentrically with respect to the core.

The layer(s) is (are) preferably organic, i.e. it (they) contains at least one organic compound as wall-forming material. Preferably, the inner and/or outer layer(s) includes at least one polymer, and in particular a hydrophilic polymer.

Polymer(s)

Preferably, the microcapsule according to the invention, and in particular the outer layer(s), comprises (comprises) hydrophilic polymers chosen from the group consisting of polysaccharides and derivatives, homopolymers or copolymers of acrylic acid or methacrylic or salts and esters thereof, and mixtures thereof.

In a preferred embodiment, the microcapsule according to the invention, and in particular the outer layer(s), comprises (comprises) hydrophilic polymers chosen from the group consisting of polysaccharides and derivatives, and especially starch polymers.

Said polymer(s) is (are) advantageously chosen from (poly)(alkyl)(meth)acrylic acid and its derivatives, in particular (poly)(alkyl)(meth)acrylate and its derivatives , preferably from alkylacrylic acid/alkylmethacrylic acid copolymers and their derivatives, and is (are) preferably a copolymer of ethyl acrylate, methyl methacrylate and low ester of methacrylic acid containing quaternary ammonium groups supplied under the EUDRAGIT RSPO brand of Evonik Degussa.

Said polysaccharides and derivatives are preferably chosen from chitosan polymers, chitin polymers, cellulose polymers, starch polymers, galactomannans, alginates, carrageenans, mucopolysaccharides and their derivatives, as well as the mixture of these.

In a preferred embodiment, the outer layer(s) is (are) free of microcrystalline cellulose.

According to a particularly preferred embodiment, said polysaccharides and their derivatives are preferably chosen from those which include a type of ose or several types of ose, preferably several types of ose, in particular at least one (several) units (s) D-Glucose as ose(s), preferably starch polymers, cellulose polymers, and derivatives thereof, and mixtures thereof.

According to a preferred embodiment, the microcapsule contains at least one hydrophilic polymer chosen from the group consisting of starch and its derivatives, in particular corn starch, cellulose and its derivatives, homo- and/or copolymer of methacrylic acid and/or methacrylic acid ester or copolymer of (alkyl)acrylic acid and/or (alkyl)methacrylic acid and their derivatives, preferably their salts and their ester, and in particular the capsule contains polymethyl methacrylate.

According to a preferred embodiment, the microcapsule contains at least one hydrophilic polymer chosen from the group consisting of starch and its derivatives, in particular corn starch.

The starch that can be used according to the present invention generally comes from vegetable raw materials, such as rice, soybeans, potatoes or corn. The starch can be unmodified starch or (by analogy with cellulose) modified starch. In a preferred embodiment, the starch is unmodified.

The preferred homo- and/or co-polymers of methacrylic acid and/or methacrylic acid ester are those in which the copolymer of methyl methacrylate and ethyl acrylate has a molecular weight of 750 to 850 kDa .

Cellulose derivatives include, for example, alkaline celluloses, carboxymethylcellulose (CMC), cellulose esters and ethers, and aminocelluloses. In a particular embodiment, the cellulose is a carboxymethylcellulose (CMC).

According to a preferred embodiment, the capsule contains at least one starch derivative, in particular corn starch, polymethyl methacrylate, a copolymer of (alkyl)acrylic acid and/or of (alkyl) methacrylic acid and their derivatives, preferably their salts and their ester, and/or a cellulose derivative.

Preferably, the microcapsule contains uncrosslinked polymer(s).

The polymer(s) may be in one or more layers.

In another embodiment, the polymer(s) may be in the core.

The microcapsule may contain polymer(s) in the core and/or in the layer(s).

In a particular embodiment, the polymer(s) are located in the core and in the layer(s).

In one embodiment, the core contains at least starch and/or a cellulose derivative as polymer(s). When starch is contained in the kernel, it represents the main ingredient of such a kernel, i.e. the amount of starch by weight is greater than the respective amount of the other compounds of the kernel.

The polymer can represent from 0.5 to 20% by weight of the microcapsule, in particular from 1 to 10% by weight, preferably from 2 to 8% by weight of the microcapsule.

The different layers forming the coating can be based on identical or different polymers. They will advantageously be formed from the same polymer.

On the other hand, the layers will advantageously be of different colors.

This different color can be obtained by the use of different colorants but also by the use of different concentrations in at least one colorant when the colorant will be the same for two layers.

In a particular embodiment, the outer layer contains at least one colorant.

In another embodiment, the outer layer contains no colorant.

Colorant(s)

As previously stated, the term "colorant" includes any organic or inorganic pigment or dye approved for use in cosmetics by the CTFA and FDA and used in cosmetic formulations.

Thus, the term "dye" refers to organic pigments such as synthetic or natural dyes chosen from the well-known FD&C or D&C dyes, to inorganic pigments such as metal oxides, or to lakes such as those based on cochineal carmine. , barium, strontium, calcium or aluminum and any combination (mixture) of these. These dyes are detailed below.

In a particular embodiment, the colorant may be water-soluble or water-dispersible.

In another embodiment, the colorant useful according to the present invention may be oil soluble or oil dispersible or have limited water solubility.

In preferred embodiments, the colorant is an inorganic pigment, more preferably a metal oxide.

Advantageously, the dyes of the multilayer microcapsules are primary metal oxides chosen from iron oxides, titanium dioxide, aluminum oxide, zirconium oxides, cobalt oxides, cerium oxides, nickel, tin oxide or zinc oxide, or composite oxides, more preferably an iron oxide selected from red iron oxide, yellow iron oxide or iron oxide black, or a mixture thereof.

The layer(s) may also contain lacquers corresponding to an organic dye attached to a substrate. This (these) lacquer(s) is (are) advantageously chosen from the materials below, and their mixture(s):

- cochineal carmine;

- organic pigments of azo, anthraquinone, indigoid, xanthene, pyrene, quinoeline, triphenylmethane, fluorane dyes; Among the organic pigments, mention may be made of those known under the following brands: D&C Blue No. 4, D&C Brown No. 1, D&C Green No. 5, D&C Green No. 6, D&C Orange No. 4, D&C Orange No. 5 , D&C Orange #10, D&C Orange #11, D&C Red #6, D&C Red #7, D&C Red #17, D&C Red #21, D&C Red #22, D&C Red #27, D&C Red #28, D&C Red #30, D&C Red #31, D&C Red #33, D&C Red #34, D&C Red #36, D&C Violet #2, D&C Yellow #7, D&C Yellow # #8, D&C Yellow #10, D&C Yellow #11, FD&C Blue #1, FD&C Green #3, FD&C Red #40, FD&C Yellow #5, FD&C Yellow #6;

- water-insoluble salts of sodium, potassium, calcium, barium, aluminium, zirconium, strontium, titanium, acid dyes such as azo, anthraquinone, indigoid, xanthenic, pyrenic, quinoline, triphenylmethane, fluorane dyes, these dyes may include at least one carboxylic or sulfonic acid group.

Organic lacquers can also be protected with an organic carrier such as rosin or aluminum benzoate.

Among the organic lakes, mention may be made in particular of those known under the following names: D&C Red n° 2 Aluminum lake, D&C Red n° 3 Aluminum lake, D&C Red n° 4 Aluminum lake, D&C Red n° 6 Aluminum lake, D&C Red #6 Barium lake, D&C Red #6 Barium/Strontium lake, D&C Red #6 Strontium lake, D&C Red #6 Potassium lake, D&C Red #6 Sodium lake, D&C Red #7 Aluminum lake, D&C Red #7 Barium lake, D&C Red #7 Calcium lake, D&C Red #7 Calcium/Strontium lake, D&C Red #7 Zirconium lake, D&C Red #8 Sodium lake, D&C Red #9 Aluminum lake, D&C Red #9 Barium lake, D&C Red #9 Barium/Strontium lake, D&C Red #9 Zirconium lake, D&C Red #10 Sodium lake, D&C Red #19 Aluminum lake, D&C Red #19 Barium lake, D&C Red #19 Zirconium lake, D&C Red #21 Aluminum lake, D&C Red #21 Zirconium lake, D&C Red #22 Aluminum lake, D&C Red #27 Aluminum lake, D&C Red #27 Aluminum/Titanium/Zirconium lake, D&C Red #27 Barium lake, D&C Red #27 Calcium lake, D&C Red #27 Zirconium lake, D&C Red #28 Aluminum lake, D&C Red #28 Sodium lake D&C Red #30 lake, D&C Red #31 Calcium lake, D&C Red #33 Aluminum lake, D&C Red #34 Calcium lake, D&C Red #36 lake, D&C Red #40 Aluminum lake, D&C Blue #1 Aluminum lake, D&C Green #3 Aluminum lake, D&C Orange #4 Aluminum lake, D&C Orange #5 Aluminum lake, D&C Orange #5 Zirconium lake, D&C Orange #10 Aluminum lake, D&C Orange #17 Barium lake, D&C Yellow #5 Aluminum lake, D&C Yellow #5 Zirconium lake, D&C Yellow #6 Aluminum lake, D&C Yellow #7 Zirconium lake , D&C Yellow #10 Aluminum lake, FD&C Blue #1 Aluminum lake, FD&C Red #4 Aluminum lake, FD&C Red #40 Aluminum lake, FD&C Yellow #5 Aluminum lake, FD&C Yellow #6 Aluminum lake.

The chemical substances corresponding to each of these organic dyes mentioned above are mentioned in the work entitled "International Cosmetic Ingredient Dictionary and Handbook", 1997 edition, pages 371 to 386 and 524 to 528, published by "The Cosmetic, Toiletry, and Fragrance Association”, the contents of which are incorporated by reference into this specification.

According to a preferred embodiment, the lacquer(s) is (are) chosen from cochineal carmine and the water-insoluble salts of sodium, potassium, calcium, barium, aluminium, zirconium, strontium, titanium, acid dyes such as azo, anthraquinone, indigoid, xanthene, pyrene, quinoline, triphenylmethane, fluorane dyes, it being understood that these dyes may include at least one carboxylic or sulphonic acid group, and their mixture.

According to a preferred embodiment, the lacquer(s) is/are chosen from cochineal carmine and water-insoluble salts of sodium, calcium, aluminum, and a mixture thereof.

As lacquer containing carmine, we can cite the commercial references: CARMIN COVALAC W 3508, CLOISONNE RED 424C and CHROMA-LITE MAGENTA CL4505.

The water-insoluble aluminum salts are preferably chosen from FDC Yellow No. 5 aluminum lake, FDC Blue No. 1 aluminum lake, FDC Red No. 40 aluminum lake, FDC Red No. 30 aluminum lake, FDC Green N°5 aluminum lake, and mixtures thereof. As compound incorporating this inorganic lacquer, mention may in particular be made of the commercial references: INTENZA FIREFLY C91-1211, INTENZA AZURE ALLURE C91-1251, INTENZA THINK PINK C91-1236

The water-insoluble calcium salts are preferably selected from Red N°7 calcium lake. As compound incorporating this inorganic lacquer, mention may in particular be made of the commercial references: INTENZA MAGENTITUDE C91-1234, INTENZA HAUTE PINK C91-1232, INTENZA RAZZLED ROSE C91-1231, INTENZA AMETHYST FORCE C91-7231, INTENZA PLUSH PLUM C91-7441, INTENZA ELECTRIC CORAL C91-1233, FLORASOMES-JOJOBA-SMS-10% CELLINI RED-NATURAL and their mixture.

The water-insoluble sodium salts are preferably chosen from Red No. 6 sodium lake and Red No. 28 sodium lake, and their mixture. As compound incorporating this inorganic lacquer, mention may in particular be made of the commercial references: INTENZA MANGO TANGO C91-1221 and INTENZA NITRO PINK C91-1235.

In preferred embodiments, the colorant is an inorganic colorant.

In a preferred embodiment, the colorant is a metal oxide. This metal oxide is preferably chosen from iron oxides, titanium oxides and mixtures thereof.

The color-changing compositions of the invention may comprise a mixture of two or more colorants, either individually encapsulated in microcapsules and/or one or more mixtures of colorants encapsulated in the multilayered microcapsules.

According to this specific embodiment, each layer of the microcapsule may contain at least one specific colorant or a specific mixture of colorant(s).

According to this specific embodiment, the color-changing composition of the invention comprises two or more microcapsules of the invention having different colors.

A person skilled in the art knows how to choose colorants and combinations of colorants to produce a desired color effect or color change.

As indicated previously, the microcapsules of the invention preferably contain at least titanium dioxide and/or iron oxides in their coating, preferably at least titanium dioxide.

In a preferred embodiment, the microcapsules of the invention preferably contain at least titanium dioxide and iron oxides in their coating.

According to a specific embodiment, the outer layer of said microcapsules contains titanium dioxide and, more preferably, only colorant.

According to a specific embodiment, the composition according to the invention is a colorless, “uncolored” or “colorless” composition, that is to say a transparent or white composition.

According to a preferred embodiment, the composition according to the present invention comprises uncolored microcapsules, that is to say that the outer layer is white or transparent, and when the outer layer is transparent, the visible inner layer is white. For the purposes of the present invention, the term "transparent composition" means a composition which transmits at least 40% of the light at a wavelength of 750 nm without scattering it, that is to say a composition in which the The light scatter angle is less than 5° and more preferably is about 0°.

The transparent composition can transmit at least 50%, in particular at least 60% and in particular at least 70% of the light at a wavelength of 750 nm.

The transmission is measured with a Cary 300 Scan UV-visible spectrophotometer from Varian, according to the following protocol:

- the composition is poured into a square-sided spectrophotometer tank with a length of 10 mm;

- the sample of the composition is then kept in a room thermostated at 20°C for 24 hours;

- the light transmitted through the sample of the composition is then measured on the spectrophotometer by scanning wavelengths ranging from 700 nm to 800 nm, the measurement being carried out in transmission mode;

- the percentage of light transmitted through the sample of the composition at a wavelength of 750 nm is then determined.

Transparent compositions, when placed 0.01 m in front of a black line 2 mm in diameter drawn on a sheet of white paper, allow this line to be seen; on the other hand, an opaque composition, that is to say not transparent, does not allow the line to be seen.

According to a specific embodiment, the outer layer of said microcapsules contains organic pigments or iron oxides.

The dyes are present in amounts ranging from 20 to 90% by weight, preferably from 30 to 80% by weight, more preferably from 50 to 75% by weight relative to the total weight of the microcapsule.

In a particular embodiment, the microcapsules contain metal oxides chosen from iron oxides, titanium oxides and mixtures thereof, present in a range of 20 to 90% by weight, preferably from 30 to 85 wt%, more preferably 50 to 85 wt% based on the total weight of the microcapsule.

In particular, the titanium oxide may be present in an amount ranging from 28% to 80% by weight, preferably from 30% to 75% by weight, and more preferably from 30% to 50% by weight, per relative to the total weight of the microcapsule.

In a particular embodiment, the microcapsule according to the invention comprises titanium dioxide in an amount of 50% to 80%, in particular from 55% to 70%, and more particularly from 55% to 65% by weight, by relative to the total weight of the microcapsule.

In particular, the iron oxides can be present in a proportion of 5 to 75% by weight, preferably 8 to 65% by weight relative to the total weight of the microcapsule. In a particular embodiment, the iron oxides are present in an amount greater than 15% by weight, preferably greater than 30% by weight, and in particular from 40 to 65% by weight relative to the total weight of the microcapsule .

In a preferred embodiment, in at least one layer, and preferably in each layer, the colorants are the main ingredients, i.e. they represent at least 40% by weight of the layer(s). (s), preferably at least 75% by weight of the layer(s), more preferably at least 95% by weight of the layer(s).

In a preferred embodiment, the average thickness of the titanium dioxide layer ranges from 5 µm to 150 µm.

Lipid-based material

The inner and/or outer layer(s) may also advantageously include at least one lipid-based material.

According to a particular embodiment of this invention, such a lipid-based material can have amphiphilic properties, that is to say have an apolar part and a polar part.

Such a lipid-based material may include at least one or more C ₁₂ -C ₂₂ fatty acid chains such as those selected from stearic acid, palmitic acid, oleic acid, linoleic acid, linolenic acid, etc. and mixtures thereof. Preferably, these fatty acid chains are hydrogenated. Finally, these fatty acid chains can constitute the apolar part of a lipid-based material.

This lipid-based material is preferably chosen from phospholipids. These phospholipids are preferably chosen from phosphoacylglycerols, more preferably from lecithins, and are in particular hydrogenated lecithins.

The lipid-based material can represent from 0.05 to 5% by weight of the microcapsule, in particular from 0.1 to 1% by weight of the microcapsule.

By combining three or more compounds (e.g. sugar alcohols, polymers, lipid-based material) of different hardness and/or water solubility in the microcapsule, the time required for degradation can be adjusted. dye-encapsulated microcapsules on the skin, so that by varying the method or intensity of application to the skin, the preferred coloration or gradation pattern can be adjusted.

Thus, according to a preferred embodiment, the multilayer coating contains at least starch as polymer and at least one lipid-based material, preferably lecithin.

According to an advantageous embodiment, the microcapsules according to the invention include at least one monosaccharide or its derivative and at least one polysaccharide or its derivatives.

According to a preferred embodiment, the microcapsules include a core comprising a monosaccharide derivative and a coating comprising a polysaccharide (or its derivative) including one type of sugar or several types of sugar, preferably several types of sugar.

According to a more preferred embodiment, the microcapsules include a core comprising a monosaccharide-polyol, preferably chosen from mannitol, erythritol, xylitol, sorbitol, and a coating comprising a polysaccharide (or its derivative) including as ose (s) at least one or more D-Glucose units.

According to a preferred embodiment, the microcapsules include three or more colorants in different layers.

According to a preferred embodiment, the microcapsules also include a material based on lipids chosen from phospholipids, advantageously chosen from phosphoacylglycerol and in particular from lecithins.

In a particular embodiment, the microcapsule contains mannitol, a starch polymer and a lipid-based material.

By referring to the , according to a preferred embodiment, the present invention advantageously provides a color-changing microcapsule having a size range from 10 µm to 800 µm, preferably from 50 µm to 600 µm and more preferably from 60 µm to 250 µm in diameter of the microcapsule, comprising:

i) a core (A), preferably having a size ranging from 500 nm to 150 μm in diameter, which preferably does not contain any dye, and comprising at least one organic core preferably chosen from at least one sugar alcohol, preferably a monosaccharide-polyol advantageously chosen from mannitol, erythritol, xylitol, sorbitol and a mixture thereof;

ii) a first layer (B) surrounding said core comprising:

- at least one colorant, preferably iron oxide(s), and

- a binder chosen from at least one polymer, at least one lipid-based material, and their mixture, preferably their mixture;

iii) a second layer (C) surrounding said first layer (B), preferably with a thickness of 5 to 500 µm, comprising:

- particles of titanium dioxide, and

- a binder chosen from at least one polymer, at least one lipid-based material, and their mixture, preferably their mixture;

iv) optionally a third layer (D) surrounding said second layer (C) comprising:

- at least one colorant, and

- a binder chosen from at least one polymer, at least one lipid-based material, and their mixture, preferably their mixture;

v) optionally a fourth layer (E) surrounding said third layer (D), if applicable, or surrounding said second layer (C) comprising

- at least one polymer forming a wall preferably chosen from polysaccharides such as cellulose derivatives, in particular cellulose ether and ester, from (poly)(alkyl)(meth)acrylic acid and its derivatives, in particular (poly)(alkyl)(meth)acrylate and its derivatives, and preferably from alkylacrylic acid/alkylmethacrylic acid copolymers and their derivatives.

In a preferred embodiment, the polymer is a hydrophilic polymer selected from the group consisting of starch and its derivatives, in particular corn starch.

Examples of commercially available microcapsules for use in the composition of the invention include the following microcapsules produced by Korea Particle Technology KPT under the trade names:

- Magic50-BW0105, Magic50-BW0105-00, Magic50-BW0105-01, Magic50-BW0105-03, Magic50-BP905, Magic30-BW0105 from KPT: ash-grey spherical microcapsules containing mannitol, red iron oxide, yellow iron oxide, black iron oxide, hydrogenated lecithin, titanium dioxide, Zea mays (corn) starch, having a particle size of 60 to 200 mesh.

The microcapsules suitable for the present invention are stable in the compositions according to the present invention, preferably at high temperatures, for example greater than or equal to 40° C., for example for one month, better two months and even better three months in a oven at 45°C or for 15 days in an oven at 60°C.

In a preferred embodiment, the microcapsules according to the present invention exhibit suitable softening kinetics, making it possible to provide not only aesthetic microcapsules but also generally aesthetic compositions.

In particular, the composition can lead to different shades or gradations of colors depending on the intensity of the friction. The compositions can advantageously exhibit a high C* chromaticity as measured in the CIE Lab 1976 system.

COMPOUND OF SALICYLIC ACID AND DERIVATIVES

The composition of the invention comprises a salicylic acid compound, advantageously chosen from salicylic acid and the compounds of formula (I) below:

(I)

in which :

- the radical R denotes a saturated, linear, branched or cyclic aliphatic chain, containing from 2 to 22 carbon atoms; an unsaturated chain containing from 2 to 22 carbon atoms comprising one or more optionally conjugated double bonds; an aromatic ring linked to the carbonyl radical directly or via saturated or unsaturated aliphatic chains containing 2 to 7 carbon atoms; said groups being able to be substituted by one or more substituents, identical or different, chosen from (a) halogen atoms, (b) the trifluoromethyl group, (c) hydroxyl groups in the free form or esterified by an acid containing 1 with 6 carbon atoms, or (d) a carboxyl function in the free form or esterified with a lower alcohol containing from 1 to 6 carbon atoms;

- R' is a hydroxyl group;

- as well as the salts thereof derived from an inorganic or organic base.

Preferably, the radical R denotes a saturated, linear, branched or cyclic aliphatic chain, containing from 3 to 11 carbon atoms; an unsaturated chain containing from 3 to 17 carbon atoms and comprising one or more conjugated or unconjugated double bonds; said hydrocarbon chains possibly being substituted by one or more substituents, identical or different, chosen from (a) halogen atoms, (b) the trifluoromethyl group, (c) hydroxyl groups in free form or esterified with an acid containing 1 to 6 carbon atoms, or (d) a carboxyl function in the free form or esterified with a lower alcohol containing from 1 to 6 carbon atoms;

- as well as the salts thereof obtained by salification with an inorganic or organic base.

The compounds which are more particularly preferred are those in which the radical R is a C ₃ -C ₁₁ alkyl group.

Among the particularly preferred compounds of formula (I), mention may be made of:

5-n-octanoylsalicylic acid (or capryloylsalicylic acid); 5-n-decanoylsalicylic acid; 5-n-dodecanoyl-salicylic acid; 5-n-heptyloxysalicylic acid, and corresponding salts thereof.

The salicylic acid compound is advantageously chosen from salicylic acid and 5-n-octanoylsalicylic acid.

The salts of the compounds of formula (I) can be obtained by salification with an inorganic or organic base. By way of example of an inorganic base, mention may be made of the hydroxides of alkali metals or alkaline earth metals, for example sodium hydroxide or potassium hydroxide, or aqueous ammonia.

Among the organic bases, mention may be made of amines and alkanolamines. Quaternary salts, for example those described in patent FR 2 607 498, are particularly advantageous.

The compounds of formula (I) which can be used according to the invention are described in US Pat. 5,267,407, US 5,667,789, US 5,580,549 and EP-A-570,230.

The salicylic acid compound as described above may be present in the composition according to the invention in a content ranging from 0.1% to 10% by weight, preferably from 0.15% to 5% by weight and preferentially from 0.20% to 3% by weight, and most preferably from 0.25% to 0.5% by weight relative to the total weight of the composition.

HYDROPHILIC GELLING AGENT

To obtain the composition according to the invention in the form of an aqueous gel, at least one hydrophilic gelling agent chosen from synthetic polymer gelling agents, natural or natural polymer gelling agents, mixed silicates and silicas is used. fumes, and mixtures thereof, in an aqueous liquid carrier. Said hydrophilic gelling agent is present in a sufficient quantity to give the composition the desired viscosity, which obviously depends on the intended use.

Preferably, the viscosity of the gel according to the invention is greater than or equal to 20UD (Mobile 3) by Rheomat at 25°C. The viscosity is generally measured at 25° with a RHEOMAT RM 180 viscometer with Mobile 3 adapted to the viscosity of the product to be tested (the mobile is chosen to have a measurement between 10 and 150 for the unit of difference UD), the measurement being made after 10 min of rotation of the mobile inside the composition, with a shear of 200 s- ¹ . The UD values can then be converted into Poise (1 Poise= 0.1 Pa.s) using a look-up table.

For the purposes of the present invention, the term “hydrophilic gelling agent” denotes a compound capable of gelling the aqueous phase of the compositions according to the invention.

The gelling agent is hydrophilic and is therefore, in this respect, present in the aqueous phase of the composition. The gelling agent can be water soluble or water dispersible.

In particular, a composition according to the invention comprises from 0.001% to 20%, from 0.01% to 10% by weight, preferably from 0.1% to 5% by weight, more preferably from 0.5% to 2.5% by weight, and better still from 1% to 2% by weight of hydrophilic gelling agent(s), relative to the total weight of the composition.

The hydrophilic gelling agent is chosen from synthetic polymeric gelling agents, natural or naturally occurring polymeric gelling agents, mixed silicates and fumed silicas, and mixtures thereof.

Preferably, the hydrophilic gelling agent is chosen from natural polymeric gelling agents or those of natural origin and synthetic polymeric gelling agents, and mixtures thereof.

I. g-agents natural polymeric elifiers s or d ' natural origin

The polymeric hydrophilic gelling agents suitable for the invention can be natural or of natural origin. For the purposes of the invention, the term “of natural origin” is intended to designate the polymeric gelling agents obtained by modification of natural polymeric gelling agents.

These gelling agents can be particulate or non-particulate.

More specifically, these gelling agents fall into the category of polysaccharides.

In general, polysaccharides can be divided into several categories.

Thus, the polysaccharides which are suitable for the invention can be homopolysaccharides such as fructans, glucans, galactans and mannans or heteropolysaccharides such as hemicellulose. Similarly, they can be linear polysaccharides such as pullulan or branched polysaccharides such as gum arabic and amylopectin, or even mixed polysaccharides such as starch. More particularly, the polysaccharides suitable for the invention can be distinguished according to whether they are starchy or not.

A.I. Starch polysaccharides

As representatives of this category, mention may more particularly be made of native starches, modified starches and particulate starches.

Native starches

The starches which can be used in the present invention are more particularly macromolecules in the form of polymers consisting of elementary fractions which are anhydroglucose (dextrose) units, linked by α(1,4) bonds of chemical formula (C ₆ H ₁₀ O ₅ ) _n . The number of these fractions and their assembly make it possible to distinguish between amylose, a molecule made up of approximately 600 to 1,000 linearly linked glucose molecules, and amylopectin, a polymer branched approximately every 25 glucose residues (α(1, 6)). The total chain can include between 10,000 and 100,000 glucose residues. Starch is described in particular in Kirk-Othmer's Encyclopaedia of Chemical Technology, ^3rd edition, volume 21, pages 492 to 507, Wiley Interscience, 1983.

The relative proportions of amylose and amylopectin, as well as their degree of polymerization, vary according to the botanical origin of the starches. The botanical origin of the starch molecules used in the present invention can be cereals or tubers. Thus, the starches are chosen, for example, from corn starch, rice starch, cassava starch, tapioca starch, barley starch, potato starch, wheat starch, sorghum starch and pea starch.

Native starches are represented, for example, by the products sold under the names C*Amilogel ^TM , Cargill Gel ^TM , C* Gel ^TM , Cargill Gum ^TM , DryGel ^TM and C*Pharm Gel ^TM by the company Cargill, under the name Corn Starch by the company Roquette, and under the name Tapioca Pure by the company National Starch.

Modified starches

The modified starches used in the composition of the invention can be modified by one or more of the following reactions: pregelatinization, degradation (acid hydrolysis, oxidation, dextrinization), substitution (esterification, etherification), crosslinking (esterification), bleaching.

According to the invention, it is also possible to use amphoteric starches, these amphoteric starches containing one or more anionic groups and one or more cationic groups. Anionic and cationic groups can be attached to the same reactive site of the starch molecule or to different reactive sites; they are preferably linked to the same reactive site. The anionic groups can be of the carboxylic, phosphate or sulphate type, preferably carboxylic. The cationic groups can be of the primary, secondary, tertiary or quaternary amine type. The amphoteric starches are chosen in particular from the compounds described in US patents 5,455,340 and US 4,017,460.

Starch molecules can be derived from any plant source of starch, including corn, potato, oats, rice, tapioca, sorghum, barley, or wheat. It is also possible to use the hydrolysates of the starches mentioned above.

Modified starches are represented, for example, by products sold under the names C*Tex-Instant (pregelatinized adipate), C*StabiTex-Instant (pregelatinized phosphate), C*PolarTex-Instant (pregelatinized hydroxypropyl), C*Set ( acid hydrolysis, oxidation), C*size (oxidation), C*BatterCrisp (oxidation), C*DrySet (dextrinization), C*Tex ^TM (acetyl distarch adipate), C*PolarTex ^TM (distarch hydroxypropyl phosphate), C* StabiTex ^TM (distarch phosphate), distarch acetyl phosphate) by the company Cargill, by distarch phosphates or compounds rich in distarch phosphate such as the product sold under the references Prejel VA-70-T AGGL ( hydroxypropyl phosphate of gelatinized cassava distarch) or Prejel TK1 (gelatinized cassava distarch phosphate) or Prejel 200 (gelatinized cassava distarch acetyl phosphate) by the company Avebe or Structure Zea of National Starch (gelatinized maize distarch phosphate ).

Particulate starches

Particulate starches which may be specifically mentioned include

- starches grafted with an acrylic polymer (homopolymer or copolymer) and especially with sodium polyacrylate, for example those sold under the names Sanfresh ST100MC by the company Sanyo Chemical Industries or Makimousse 25, Makimousse 12 by the company Daito Kasei (INCI name : Sodium polyacrylate starch),

- hydrolyzed starches grafted with an acrylic polymer (homopolymer or copolymer) and in particular an acryloacrylamide/sodium acrylate copolymer, for example those sold under the names Water Lock A-240, A-180, B-204, D-223 , A-100, C-200 and D-223 by the company Grain Processing (INCI name: Starch/acrylamide/sodium acrylate copolymer);

- polymers based on starch, gum and cellulose derivative, such as the product containing starch and sodium carboxymethylcellulose, for example the product sold under the name Lysorb 220 by the company Lysac.

Mention may also be made of C ₁ -C ₄ carboxyalkyl starches, also referred to below as "carboxyalkyl starch", obtained by grafting carboxyalkyl groups onto one or more alcoholic functions of the starch, in particular by reaction of the starch and the sodium monochloroacetate in an alkaline medium. The carboxyalkylated starches are advantageously used in the form of salts and in particular of salts of alkali or alkaline-earth metals such as Na, K, Li, NH ₄ , or of salts of a quaternary ammonium or of an organic amine such as monoethanolamine , diethanolamine or triethanolamine. The carboxyalkyl starches used in the invention can be chosen from carboxyalkyl potato starches, such as sodium salts of carboxyalkyl starch, in particular a sodium salt of carboxymethyl potato starch, sold in particular under the name of Primojel ^® by the company DMV International or Glycolys ^® and Glycolys ^® LV by the company Roquette.

I.B. Non-starch polysaccharides

According to a variant of an embodiment, the hydrophilic gelling agent is non-starchy.

In general, the non-starch polysaccharides can be chosen from polysaccharides produced by microorganisms, polysaccharides isolated from algae and polysaccharides from higher plants, such as homogeneous polysaccharides, in particular celluloses and derivatives thereof or fructans, heterogeneous polysaccharides such as gum arabic, galactomannans, glucomannans and pectins, and derivatives thereof, as well as mixtures thereof.

In particular, the polysaccharides can be chosen from fructans, gellans, glucans, amylose, amylopectin, glycogen, pullulan, dextrans, celluloses and derivatives thereof, in particular methylcelluloses, hydroxyalkylcelluloses, ethylhydroxyethylcelluloses and carboxymethylcelluloses, mannans, xylans, lignins , arabans, galactans, galacturonans, alginate compounds, chitin, chitosans, glucuronoxylans, arabinoxylans, xyloglucans, glucomannans, pectic acids and pectins, arabinogalactans, carrageenans, agars, glycosaminoglucans, gum arabic, gum tragacanth, gum ghatti, gum karaya, locust bean gum, galactomannans such as guar gums and nonionic derivatives thereof, in particular hydroxypropylguar, and ionic derivatives thereof, biopolysaccharide gums of microbial origin, in particular scleroglucan or xanthan gums, mucopolysaccharides, especially chondroite sulfates ine, and mixtures thereof.

These polysaccharides can be chemically modified, in particular by urea or urethane groups or by a reaction of hydrolysis, oxidation, esterification, etherification, sulfation, phosphatation, amination, amidation or alkylation, or by several of these modifications. The derivatives obtained can be anionic, cationic, amphoteric or nonionic.

The polysaccharides can advantageously be chosen from carrageenans, in particular kappa carrageenan, gellan gum, agar-agar, xanthan gum, alginate-based compounds, in particular sodium alginate, scleroglucan gum , guar gum, inulin and pullulan, and mixtures thereof.

In general, the compounds of this type which can be used in the present invention are chosen from those described in particular Kirk-Othmer's Encyclopedia of Chemical Technology, third edition, 1982, volume 3, pages 896 to 900, and volume 15, pages 439 to 458, in Polymers in Nature by E.A. MacGregor and C.T. Greenwood, published by John Wiley & Sons, Chapter 6, pages 240-328, 1980, in Robert L. Davidson's Handbook of Water-Soluble Gums and Resins published by McGraw Hill Book Company (1980) and in Industrial Gums - Polysaccharides and their Derivatives, edited by Roy L. Whistler, second edition, published by Academic Press Inc.

More specifically, these polysaccharides suitable for the invention can be distinguished according to whether they are derived from microorganisms, algae or higher plants.

Polysaccharides produced by microorganisms

Xanthan

Xanthan is a heteropolysaccharide produced on an industrial scale by the aerobic fermentation of the bacterium Xanthomonas campestris. Xanthan gums are represented, for example, by the products sold under the names Rhodicare by the company Rhodia Chimie, under the name Satiaxane™ by the company Cargill Texturizing Solutions (for the food, cosmetics and pharmaceutical industries), under the name Novaxan™ by ADM, and under the names Kelzan® and Keltrol® by CP-Kelco.

Pullulan

Pullulan is a polysaccharide made up of maltotriose units, known as α(1,4)-α(1,6)-glucan. Pullulan is produced, for example, under the reference Pullulan PF 20 by the Hayashibara group in Japan.

Dextran and dextran sulphate

Dextran is a neutral polysaccharide bearing no charged groups, biologically inert, prepared by fermentation of beet sugar containing only hydroxyl groups. Dextran is represented, for example, by the products sold under the name Dextran or Dextran T by the company Pharmacosmos, or under the name Dextran 40 Powder or Dextran 70 Powder by the company Meito Sangyo Co. Dextran sulphate is sold by PK Chemical A/S as Dextran sulfate.

Succinoglycan

Succinoglycan is a high molecular weight extracellular polymer produced by bacterial fermentation, consisting of repeating units of octasaccharides (repeating 8 sugars). Succinoglycans are sold, for example, under the name Rheozan by the company Rhodia.

Scleroglucan

Scleroglucan is a nonionic branched homopolysaccharide composed of β-D-glucan units. Scleroglucan is sold, for example, under the name Amigel by the company Alban Müller, or under the name Actigum™ CS by the company Cargill.

gellan gum

Gellan gum is an anionic linear heteropolysaccharide based on oligosaccharide units composed of 4 saccharides (tetra-saccharide). It is sold, for example, under the name Kelcogel CG LA by the company CP Kelco.

Polysaccharides isolated from algae

galactans

The polysaccharide used in the invention may be a galactan chosen especially from agar and carrageenans. Carrageenans are anionic polysaccharides constituting the cell walls of various red algae (Rhodophyceae) and are composed of two D-galactopyranose units linked alternately by α(1,3) and ß(1,4) bonds. Depending on the number and position of sulfate-ester groups on the repeating disaccharide of the molecule, several types of carrageenans are distinguished, namely: kappa-carrageenans, which carry a sulfate-ester group, iota-carrageenans, which carry two sulfate-ester groups, and lambda-carrageenans, which carry three sulfate-ester groups. Carrageenans are notably sold by the company SEPPIC under the name Solagum ^® , by the company Gelymar under the names Carragel ^® , Carralact ^® and Carrasol ^® , by the company Cargill under the names Satiagel™ and Satiagum™, and by the CP-Kelco under the names of Genulacta ^® , Genugel ^® and Genuvisco ^® .

Agar-like galactans are galactose polysaccharides contained in the cell wall of some of these species of red algae (Rhodophyceae), and are formed from a group of polymers whose basic skeleton is a β(1,3) D-galactopyranose and an α(1,4) L 3-6 anhydrogalactose chain, these units repeating regularly and alternately. Agar is produced, for example, by the B&V Agar Producers group under the names Gold Agar, Agarite and Grand Agar by the company Hispanagar, and under the names Agar-Agar, QSA (Quick Soluble Agar), and Puragar by the company Setexam.

Furcellarane

Furcellarane is obtained commercially from the red algae Furcellaria fasztigiata. Furcellarane is produced, for example, by Est-Agar.

Alginate-based compound

For the purposes of the invention, the term “compound based on alginate” denotes alginic acid, derivatives of alginic acid and salts of alginic acid (alginates) or of said derivatives. Preferably, the alginate compound is water soluble. According to a preferred embodiment, the alginate-based compound is alginic acid and/or a salt thereof, and preferably sodium alginate. The alginate-based compound can be chemically modified, in particular by urea or urethane groups or by a reaction of hydrolysis, oxidation, esterification, etherification, sulfation, phosphatation, amination, amidation or alkylation, or by several of these modifications. The alginate-based compounds suitable for the invention can be represented, for example, by the products sold under the names Kelcosol, Satialgine™, Cecalgum™ or Algogel™ by the company Cargill Products, under the name Protanal™ by the company FMC Biopolymer, under the name Grindsted ^® Alginate by Danisco, under the name Kimica Algin by Kimica, and under the names Manucol ^® and Manugel ^® by ISP.

Polysaccharides from higher plants

This category of polysaccharides can be divided into homogeneous polysaccharides (a single species of saccharide) and heterogeneous polysaccharides composed of several types of saccharides.

a) Homogeneous polysaccharides and derivatives thereof

The polysaccharide according to the invention can be chosen from celluloses and their derivatives or fructans.

Cellulose and derivatives

The polysaccharide according to the invention can also be a cellulose or a derivative thereof, in particular cellulose ethers or esters (for example: methylcellulose, carboxymethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxymethylpropylcellulose, cellulose acetate, cellulose nitrate , nitrocellulose).

The invention may also contain an associative polymer based on cellulose. According to the invention, the term “cellulose-based compound” designates any polysaccharide compound bearing in its structure linear sequences of anhydroglucopyranose (AGU) residues linked together by β(1,4) glycosidic bonds.

Cellulose hydroxyl groups can react partially or totally with various chemical reagents to give cellulose derivatives with intrinsic properties. Cellulose derivatives can be anionic, cationic, amphoteric or nonionic. Among these derivatives, a distinction is made between cellulose ethers, cellulose esters and cellulose ester ethers.

Among the nonionic cellulose ethers, mention may be made of alkylcelluloses such as methylcelluloses and ethylcelluloses; hydroxyalkylcelluloses such as hydroxymethylcelluloses, hydroxyethylcelluloses and hydroxypropylcelluloses; and mixed hydroxyalkylalkylcelluloses such as hydroxypropylmethylcelluloses, hydroxyethylmethylcelluloses, hydroxyethylethylcelluloses and hydroxybutylmethylcelluloses.

Among the anionic cellulose ethers, mention may be made of carboxyalkylcelluloses and the salts thereof. By way of example, mention may be made of carboxymethylcelluloses, carboxymethylmethylcelluloses and carboxymethylhydroxyethylcelluloses and the sodium salts thereof.

Among the cationic cellulose ethers, mention may be made of crosslinked or non-crosslinked and quaternized hydroxyethylcelluloses. Among the examples of quaternized alkylhydroxyethylcelluloses containing C ₈ -C ₃₀ fatty chains which can be indicated, one can include the products Quatrisoft LM 200, Quatrisoft LM-X 529-18-A, Quatrisoft LM-X 529-18B (alkyl in C ₁₂ ) and Quatrisoft LM-X 529-8 (alkyl in C ₁₈ ) sold by the company Amerchol and the products Crodacel QM, Crodacel QL (alkyl in C ₁₂ ) and Crodacel QS (alkyl in C ₁₈ ) sold by the company Croda.

Among the cellulose derivatives, mention may also be made of

- celluloses modified by groups comprising at least one fatty chain, for example hydroxyethylcelluloses modified by groups comprising at least one fatty chain, such as alkyl groups, in particular C ₈ -C ₂₂ , arylalkyl and alkylaryl groups, such than Natrosol Plus Grade 330 CS (C ₁₆ alkyls) sold by the company Aqualon, and

- Cellulose modified with polyalkylene glycol alkylphenyl ether groups, such as the product Amercell Polymer HM-1500 (nonylphenyl polyethylene glycol (15) ether) sold by the company Amerchol.

Cellulose esters include inorganic cellulose esters (cellulose nitrates, sulfates, phosphates, etc.), organic cellulose esters (cellulose monoacetates, triacetates, amidopropionates, acetatebutyrates, cellulose acetatepropionates and acetatetrimellitates, etc.), and mixed organic/inorganic esters of cellulose, such as cellulose acetatebutyrate sulfates and cellulose acetatepropionate sulfates. Among the cellulose ester ethers, mention may be made of hydroxypropylmethylcellulose phthalates and ethylcellulose sulphates.

Cellulose and derivatives are represented, for example, by the products sold under the names Avicel ^® (microcrystalline cellulose, MCC) by the company FMC Biopolymers, under the name Cekol (carboxymethylcellulose) by the company Noviant (CP-Kelco), under the name Akucell AF (sodium carboxymethylcellulose) by the company Akzo Nobel, under the name Methocel ^TM (cellulose ethers) and Ethocel ^TM (ethylcellulose) by the company Dow, and under the names Aqualon ^® (carboxymethylcellulose and sodium carboxymethylcellulose), Benecel ^® ( methylcellulose), Blanose ^TM (carboxymethylcellulose), Culminal ^® (methylcellulose, hydroxypropylmethylcellulose), Klucel ^® (hydroxypropylcellulose), Polysurf ^® (cetylhydroxyethylcellulose) and Natrosol ^® CS (hydroxyethylcellulose) by Hercules Aqualon.

Fructosans

The polysaccharide according to the invention may in particular be a fructan chosen from inulin and derivatives thereof (in particular dicarboxy and carboxymethyl inulin). Inulin can be obtained, for example, from chicory, dahlia or Jerusalem artichoke, preferably chicory. The inulin used for this invention is represented, for example, by the products sold under the name Beneo ^™ inulin by the company Orafti, and under the name ^Frutafit® by the company Sensus.

b) Heterogeneous polysaccharides and derivatives thereof

The polysaccharides which can be used according to the invention can be gums, for example cassia gum, karaya gum, konjac gum, tragacanth gum, tara gum, acacia gum or arabic gum.

Gum arabic

Gum arabic is a highly branched acidic polysaccharide that occurs as mixtures of potassium, magnesium and calcium salts. The monomeric elements of free acid (arabic acid) are D-galactose, L-arabinose, L-rhamnose and D-glucuronic acid.

Galactomannans (guar, carob, fenugreek, tara gum) and derivatives (guar phosphate, hydroxypropyl guar, etc.)

Galactomannans are non-ionic polysaccharides extracted from the endosperm of legume seeds, for which they constitute the storage carbohydrate. Galactomannans are macromolecules consisting of a main chain of β(1,4)-linked D-mannopyranose units, bearing side branches consisting of a single α(1,6)-linked D-galactopyranose unit at the main chain.

guar

Guar gum is characterized by a mannose/galactose ratio of around 2/1. The guar gums which can be used according to the invention can be nonionic, cationic or anionic. According to the invention, chemically modified or unmodified nonionic guar gums can be used.

Unmodified nonionic guar gums are, for example, the products sold under the names Vidogum GH, Vidogum G and Vidocrem by the company Unipektin and under the name Jaguar by the company Rhodia, under the name Meypro ^® Guar by the company Danisco , under the name Viscogum™ by the company Cargill, and under the name ^Supercol® guar gum by the company Aqualon.

The hydrolyzed nonionic guar gums which can be used according to the invention are represented, for example, by the products sold under the name ^Meyprodor® by the company Danisco.

The modified nonionic guar gums which can be used according to the invention are preferably modified with C ₁ -C ₆ hydroxyalkyl groups, among which mention may be made, for example, of the hydroxymethyl, hydroxyethyl, hydroxypropyl and hydroxybutyl groups. These nonionic guar gums optionally modified with hydroxyalkyl groups are sold, for example, under the trade names Jaguar HP60, Jaguar HP 105 and Jaguar HP 120 (hydroxypropyl guar) by the company Rhodia or under the name N-Hance ^® HP ( hydroxypropyl guar) by the company Aqualon.

In general, for the purposes of the present invention, the term "cationic galactomannan gum" refers to any galactomannan gum containing cationic groups and/or groups which can be ionized into cationic groups. The preferred cationic groups are chosen from those comprising primary, secondary, tertiary and/or quaternary amine groups.

These galactomannan gums, in particular guar gums modified with cationic groups, are products already known per se and are, for example, described in US Pat. Nos. 3,589,578 and US Pat. sold in particular under the brands Jaguar EXCEL, Jaguar C13 S, Jaguar C 15, Jaguar C 17 and Jaguar C162 (guar hydroxypropyltrimonium chloride) by the company Rhodia, under the name Amilan ^® Guar (guar hydroxypropyltrimonium chloride) by the company Degussa, and under the name N- ^Hance® 3000 (guar hydroxypropyltrimonium chloride) by the company Aqualon.

The anionic guar gums which can be used according to the invention are preferably carboxymethyl guar derivatives (carboxymethyl guar or hydroxypropyl carboxymethyl guar).

Carob

Locust bean gum is extracted from the seeds of the carob tree (Ceratonia siliqua).

The unmodified locust bean gum which can be used in this invention is sold, for example, under the name Viscogum™ by the company Cargill, under the name Vidogum L by the company Unipektin and under the name ^Grinsted® LBG by the company Danisco. Chemically modified locust bean gums which can be used in this invention can be represented, for example, by the cationic locust beans sold under the name Catinal CLB (locust bean hydroxypropyltrimonium chloride) by the company Toho.

tara gum

The tara gum which can be used in the context of this invention is sold, for example, under the name of Vidogum SP by the company Unipektin.

Glucomannans (konjac gum)

Glucomannan is a high molecular weight polysaccharide (500,000 < Mglucomannan < 2,000,000) composed of D-mannose and D-glucose units with a branch approximately every 50 or 60 units. The products which can be used according to the invention are sold, for example, under the names of Propol ^® and Rheolex ^® by the company Shimizu.

LM and HM pectins, and derivatives

Pectins are linear polymers of α-D-galacturonic acid (at least 65%) linked in positions 1 and 4 with a certain proportion of carboxylic groups esterified by a methanol group. Pectins are in particular sold by the company Cargill under the name Unipectine™, by the company CP-Kelco under the name Genu, and by Danisco under the name Grinsted Pectin.

Other polysaccharides

Among the other polysaccharides which can be used according to the invention, mention may also be made of chitin (poly-N-acetyl-D-glucosamine, β(1,4)-2-acetamido-2-deoxy-D-glucose), chitosan and its derivatives (chitosan-beta-glycerophosphate, carboxymethylchitin, etc.) such as those sold by the company France-Chitine; glycosaminoglycans (GAGs) such as hyaluronic acid, chondroitin sulphate, dermatan sulphate, keratan sulphate, and preferably hyaluronic acid; xylans (or arabinoxylans) and their derivatives.

Arabinoxylans are polymers of xylose and arabinose, all grouped together as pentosans.

II. Synthetic polymeric gelling agents

For the purposes of the invention, the term "synthetic" means that the polymer does not exist naturally and is not a derivative of a polymer of natural origin.

The synthetic polymeric hydrophilic gelling agent considered according to the invention may or may not be particulate. For the purposes of the invention, the term “particulate” means that the polymer is in the form of particles, preferably spherical.

II.A. g-agents particulate synthetic polymeric extenders

They are preferably chosen from crosslinked polymers. They may in particular be crosslinked acrylic homopolymers or copolymers, preferably partially neutralized or neutralized, and which are in the form of particles.

According to one embodiment, the particulate gelling agent according to the present invention is chosen from crosslinked sodium polyacrylates. It preferably has, in the dry or non-hydrated state, an average size less than or equal to 100 μm and preferably less than or equal to 50 μm. The average size of the particles corresponds to the mass average diameter (D50) measured by laser particle size analysis or by another equivalent method known to those skilled in the art.

As examples of crosslinked sodium polyacrylates, mention may be made of those sold under the names Octacare X100, X110 and RM100 by the company Avecia, those sold under the names Flocare GB300 and Flosorb 500 by the company SNF, those sold under the names Luquasorb 1003, Luquasorb 1010, Luquasorb 1280 and Luquasorb 1110 by the company BASF, those sold under the names Water Lock G400 and G430 (INCI name: Acrylamide/Sodium acrylate copolymer) by the company Grain Processing.

Mention may also be made of crosslinked polyacrylate microspheres, for example those sold under the name ^Aquakeep® 10 SH NF by the company Sumitomo Seika.

II.B. g-agents non-particulate synthetic polymeric elifiers

This family of gelling agents can be detailed in the following subfamilies:

1. Associative polymers,

2. Polyacrylamides and cross-linked and/or neutralized polymers and copolymers of 2-acrylamido-2-methylpropanesulfonic acid, and

3. Modified or unmodified carboxyvinyl polymers.

II.B.1 Associative polymers

For the purposes of the present invention, the term “ associative polymer ” designates any amphiphilic polymer comprising in its structure at least one fatty chain and at least one hydrophilic part. The associative polymers according to the present invention can be anionic, cationic, nonionic or amphoteric.

Anionic associative polymers

Among the associative anionic polymers which may be mentioned, mention may be made of those which comprise at least one hydrophilic unit, and at least one allyl ether unit with a fatty chain, more particularly those whose hydrophilic unit is formed by an anionic unsaturated ethylenic monomer , more particularly by a vinylcarboxylic acid and more particularly by an acrylic acid or a methacrylic acid or mixtures thereof, and of which the allylic ether unit with a fatty chain corresponds to the monomer of formula (I) below:

CH ₂ = C(R')CH ₂ OB _n R (I)

in which R' represents H or CH ₃ , B represents an ethyleneoxy radical, n is equal to zero or represents an integer ranging from 1 to 100, R represents a hydrocarbon radical chosen from alkyl, arylalkyl, aryl, alkylaryl and cycloalkyl radicals , containing from 8 to 30 carbon atoms, preferably from 10 to 24 carbon atoms and even more particularly from 12 to 18 carbon atoms.

Anionic amphiphilic polymers of this type are described and prepared, according to an emulsion polymerization process, in patent EP 0 216 479.

Among the associative anionic polymers which may also be mentioned are maleic anhydride/C ₃₀ -C ₃₈ α-olefin/alkyl maleate terpolymers, such as the maleic anhydride/C ₃₀ α-olefin copolymer product -C ₃₈ /isopropyl maleate sold under the name Performa V 1608 by the company Newphase Technologies.

Among the associative anionic polymers, mention may be made, according to a preferred embodiment, of copolymers comprising among their monomers an α,β-monoethylenically unsaturated carboxylic acid and an ester of an α,β-monoethylenically unsaturated carboxylic acid and of a oxyalkylenated fatty alcohol.

Preferably, these compounds also comprise as monomer an ester of an α,β-monoethylenically unsaturated carboxylic acid and of a C ₁ -C ₄ alcohol.

Among the examples of compounds of this type which may be mentioned, mention may be made of Aculyn 22 ^® sold by the company Röhm & Haas, which is a terpolymer of methacrylic acid/ethyl acrylate/oxyalkylenated stearyl methacrylate (comprising 20 EO units) or Aculyn 28 (methacrylic acid/ethyl acrylate/oxyethylenated behenyl methacrylate (25 EO) terpolymer).

The associative anionic polymers which may also be mentioned include anionic polymers comprising at least one hydrophilic unit of the unsaturated olefinic carboxylic acid type, and at least one hydrophobic unit exclusively of (C ₁₀ -C ₃₀ ) alkyl ester of the acid type. unsaturated carboxylic. Examples which may be mentioned include the anionic polymers described and prepared according to US Patents 3,915,921 and US 4,509,949.

Associative anionic polymers which may also be mentioned include anionic terpolymers. More particularly, an anionic terpolymer of 2-methyl-2-[(1-oxo-2-propenyl)amino]-1-propanesulfonic acid partially or totally salified in the form of an ammonium salt, of N,N-dimethylacrylamide and tetraethoxylated lauryl acrylate crosslinked with trimethylolpropane triacrylate, INCI name Polyacrylate Crosspolymer-6, such as the product sold under the trade name Sepimax ^Zen® by the company SEPPIC.

Cationic associative polymers

Cationic associative polymers which may be mentioned include polyacrylates bearing amine pendant groups.

Polyacrylates bearing quaternized or non-quaternized amine side groups contain, for example, hydrophobic groups such as steareth-20 (polyoxyethylene (20) stearyl alcohol).

Polyacrylates 8781-121B or 9492-103 from National Starch are examples of polyacrylates bearing amino side chains which may be mentioned.

Nonionic associative polymers

The nonionic associative polymers can be chosen from:

- copolymers of vinylpyrrolidone and fatty chain hydrophobic monomers;

- copolymers of C ₁ -C ₆ alkyl methacrylates or acrylates and of amphiphilic monomers comprising at least one fatty chain;

- copolymers of hydrophilic methacrylates or acrylates and hydrophobic monomers comprising at least one fatty chain, for example the copolymer of polyethylene glycol methacrylate/lauryl methacrylate;

- associative polyurethanes.

As examples of nonionic fatty-chain polyurethanes that can be used in the invention, it is also possible to use Rheolate ^® FX 1100 (copolymer of steareth-100/PEG 136/HDI (hexamethyl diisocyanate)), Rheolate ^® 205 containing a urea function, sold by the company Elementis, or Rhéolate ^® 208, 204 or 212, as well as Acrysol RM 184 or Acrysol RM 2020.

Mention may also be made of the product Elfacos ^® T210 containing a C ₁₂ -C ₁₄ alkyl chain function, and the product Elfacos ^® T212 containing a C ₁₆ - ₁₈ alkyl chain (PPG-14 Palmeth-60 Hexyl Dicarbamate), from Akzo .

Röhm &Haas' DW 1206B product containing a C ₂₀ alkyl chain and a urethane linkage, sold at 20% solids in water, can also be used.

It is also possible to use solutions or dispersions of these polymers, in particular in water or in an aqueous/alcoholic medium. Among the examples of these polymers which may be mentioned, mention may be made of Rheolate ^® 255, Rheolate ^® 278 and Rheolate ^® 244 sold by the company Elementis. DW 1206F and DW 1206J products sold by Röhm & Haas can also be used.

The associative polyurethanes which can be used according to the invention are in particular those described in the article by G. Fonnum, J. Bakke and Fk. Hansen, Colloid Polym. Science. 271, pp. 380-389 (1993).

More particularly still, according to the invention, one can also use an associative polyurethane which can be obtained by polycondensation of at least three compounds comprising (i) at least one polyethylene glycol comprising from 150 to 180 moles of ethylene oxide, (ii) stearyl or decyl alcohol, and (iii) at least one diisocyanate.

These polyurethane polyethers are notably sold by the company Röhm & Haas under the names Aculyn ^® 46 and Aculyn ^® 44. Aculyn ^® 46 is a polyethylene glycol polycondensate containing 150 or 180 moles of ethylene oxide, stearyl alcohol and of methylenebis(4-cyclohexyl isocyanate) (SMDI), at 15% by weight in a matrix of maltodextrin (4%) and water (81%), and Aculyn ^® 44 is a polycondensate of polyethylene glycol containing 150 or 180 moles of ethylene oxide, decyl alcohol and methylenebis(4-cyclohexyl isocyanate) (SMDI), at 35% by weight in a mixture of propylene glycol (39%) and water (26%).

It is also possible to use solutions or dispersions of these polymers, in particular in water or in an aqueous/alcoholic medium. Among the examples of these polymers which can be mentioned, one can include SER AD FX1010, SER AD FX1035 and SER AD 1070 from the company Elementis, as well as Rhéolate ^® 255, Rhéolate ^® 278 and Rhéolate ^® 244 sold by the company Elementis. It is also possible to use the products Aculyn ^® 44, Aculyn ^® 46, DW 1206F and DW 1206J, as well as Acrysol ^® RM 184 from Röhm & Haas, or Borchi Gel LW 44 from Borchers, and mixtures thereof.

Amphoteric associative polymers

Among the associative amphoteric polymers of the invention, mention may be made of crosslinked or uncrosslinked, branched or unbranched amphoteric polymers.

The amphoteric polymers which are particularly preferred according to the invention are chosen from acrylic acid/acrylamidopropyltrimethylammonium chloride/stearyl methacrylate copolymers.

According to a preferred embodiment, the associative polymer is chosen from nonionic associative polymers and more particularly from associative polyurethanes, such as the steareth-100/PEG-136/HDI copolymer sold under the name Rheolate FX 1100 by Elementis .

II.B.2 Polymers and copolymers of polyacrylamides and d ' 2-acrylamido-2-methylpropanesulfonic acid

The polymers used which are suitable as aqueous gelling agent for the invention may be crosslinked or non-crosslinked homopolymers or copolymers comprising at least the monomer 2-acrylamido-2-methylpropanesulfonic acid (AMPS ^® ), in a form partially or totally neutralized by a mineral base other than aqueous ammonia, such as sodium hydroxide or potassium hydroxide. They are preferably totally or almost totally neutralized, that is to say at least 90% neutralized.

These ^AMPS® polymers according to the invention may be crosslinked or non-crosslinked.

The AMPS ^® polymers suitable for the invention are soluble or dispersible in water. In this case, they are:

- either "homopolymers" comprising only AMPS monomers and, if they are crosslinked, one or more crosslinking agents such as those defined above;

- Either copolymers obtained from AMPS ^® and one or more hydrophilic or hydrophobic ethylenically unsaturated monomers and, if they are crosslinked, from one or more crosslinking agents such as those defined above. When said copolymers comprise hydrophobic ethylenically unsaturated monomers, these monomers do not contain a fatty chain and are preferably present in small amounts.

For the purposes of the present invention, the term “fatty chain” designates any chain based on hydrocarbons comprising at least 7 carbon atoms. The term “water-soluble or water-dispersible” refers to polymers which, when introduced into an aqueous phase at 25° C., at a mass concentration equal to 1%, make it possible to obtain a macroscopically homogeneous and transparent solution, i.e. that is to say a solution having a maximum value of transmission of light, at a wavelength equal to 500 nm, through a sample 1 cm thick, of at least 60% and preferably of at least 70%.

As homopolymers of AMPS soluble or dispersible in water suitable for use in the invention, mention may be made, for example, of the crosslinked or uncrosslinked polymers of sodium acrylamido-2-methylpropanesulfonate, such as those used in the commercial product Simulgel 800 (CTFA name: Sodium Polyacryloyldimethyl Taurate), crosslinked polymers of ammonium acrylamido-2-methylpropanesulfonate (INCI name: Ammonium Polydimethyltauramide) such as those described in patent EP 0 815 928 B1 and such as the product sold under the brand name Hostacerin AMPS ^® by the company Clariant.

As the water-soluble or water-dispersible AMPS copolymers according to the invention, examples which may be mentioned include:

- crosslinked acrylamide/sodium acrylamido-2-methylpropanesulfonate copolymers, such as that used in the commercial product Sepigel 305 (CTFA name: Polyacrylamide/C ₁₃ -C ₁₄ Isoparaffin/Laureth-7) or that used in the commercial product sold under the name Simulgel 600 (CTFA name: Acrylamide/Sodium acryloyldimethyltaurate/Isohexadecane/Polysorbate-80) by the company SEPPIC;

- copolymers of AMPS ^® and vinylpyrrolidone or vinylformamide, such as those used in the commercial product sold under the name Aristoflex AVC ^® by the company Clariant (CTFA name: Ammonium Acryloyldimethyltaurate/VP copolymer) but neutralized with hydroxide sodium or potassium hydroxide;

- copolymers of AMPS ^® and sodium acrylate, for example the copolymer of AMPS / sodium acrylate, such as that used in the commercial product sold under the name Simulgel EG ^® by the company SEPPIC or under the trade name Sepinov EM (CTFA name: Hydroxyethyl acrylate/Sodium acryloyldimethyltaurate copolymer);

- copolymers of AMPS ^® and hydroxyethyl acrylate, for example the copolymer of AMPS ^® / hydroxyethyl acrylate, such as that used in the commercial product sold under the name Simulgel NS ^® by the company SEPPIC (name CTFA: Hydroxyethyl acrylate/sodium acryloyldimethyltaurate copolymer (and) squalane (and) polysorbate 60), or such as the product sold under the name sodium acrylamido-2-methylpropanesulfonate copolymer/hydroxyethyl acrylate, such as the commercial product Sepinov EMT 10 (INCI name: Hydroxyethyl acrylate/Sodium acryloyldimethyltaurate copolymer).

II.B.3 Polymers carboxyvinyl modified or unmodified

The modified or unmodified carboxyvinyl polymers can be copolymers derived from the polymerization of at least one monomer (a) chosen from α,β-ethylenically unsaturated carboxylic acids or the esters thereof, with at least one ethylenically unsaturated monomer ( b) comprising a hydrophobic group.

The term " copolymers " denotes both copolymers obtained from two types of monomers and those obtained from more than two types of monomers, such as terpolymers obtained from three types of monomers.

According to a preferred embodiment, these polymers are crosslinked.

Among the polymers mentioned above, those which are most particularly preferred according to the present invention are acrylate/C ₁₀ -C ₃₀ alkyl acrylate copolymers (INCI name: Acrylates/C _10-30 Alkyl acrylate Crosspolymer) such as products sold by Lubrizol under the trade names Pemulen TR-1, Pemulen TR-2, Carbopol 1382, Carbopol EDT 2020 and Carbopol Ultrez 20 Polymer, and even more preferably Pemulen TR-2.

Among the modified or unmodified carboxyvinyl polymers, mention may also be made of sodium polyacrylates such as those sold under the name Cosmedia SP ^® containing 90% solids and 10% water, or Cosmedia SPL ^® in the form of an inverse emulsion containing approximately 60% solids, an oil (hydrogenated polydecene) and a surfactant (PPG-5 Laureth-5), both sold by the company Cognis.

Mention may also be made of partially neutralized sodium polyacrylates which are in the form of an inverse emulsion comprising at least one polar oil, for example the product sold under the name ^Luvigel® EM by the company BASF.

The modified or unmodified carboxyvinyl polymers can also be chosen from crosslinked (meth)acrylic acid homopolymers.

For the purposes of this patent application, the term “ (meth )acrylic ” means “ acrylic or methacrylic ”.

Examples that may be mentioned include the products sold by Lubrizol under the names Carbopol 910, 934, 940, 941, 934 P, 980, 981, 2984, 5984 and Carbopol Ultrez 10 Polymer, or by 3V-Sigma under the name of Synthalen ^® K, Synthalen ^® L or Synthalen ^® M.

Among the modified or unmodified carboxyvinyl polymers, mention may in particular be made of Carbopol (CTFA name: carbomer) and Pemulen (CTFA name: Acrylates/C _10-30 alkyl acrylate crosspolymer) sold by the company Lubrizol.

III. Other hydrophilic gelling agents

The hydrophilic gelling agents which are suitable for the invention can also be chosen from mixed silicates and fumed silicas.

III.A. mixed silicate

For the purposes of the present invention, the term “mixed silicate” designates all silicates of natural or synthetic origin containing several (two or more) types of cations chosen from among the alkali metals (for example Na, Li, K) or the metals alkaline earth (eg Be, Mg, Ca), transition metals and aluminum.

According to a particular embodiment, the mixed silicate(s) come(s) in the form of solid particles containing at least 10% by weight of at least one silicate with respect to the total weight of the particles. . In the rest of the present description, these particles are called “silicate particles”.

According to a particular embodiment of the invention, the silicates are phyllosilicates, namely silicates having a structure in which the tetrahedrons of SiO ₄ are organized into sheets between which the metal cations are enclosed.

The mixed silicates which are suitable for the invention can be chosen, for example, from montmorillonites, hectorites, bentonites, beidellite and saponites. According to a preferred embodiment of the invention, the mixed silicates used are more particularly chosen from hectorites and bentonites, and better still from laponites.

A family of silicates which can also be used in the compositions of the present invention is the family of laponites. Laponites are sodium and magnesium silicates which may also contain lithium, which have a layered structure similar to that of montmorillonites. Laponite is the synthetic form of the natural mineral known as hectorite. Among the laponites which may be specially mentioned are the products sold under the following names: Laponite ^® XLS, Laponite ^® XLG, Laponite ^® RD, Laponite ^® RDS, Laponite ^® XL21 (these products are sodium-magnesium silicates and sodium-lithium-magnesium) by Rockwood Additives Limited.

III.B. Hydrophilic fumed silica

The fumed silicas according to the present invention are hydrophilic.

Hydrophilic fumed silicas are obtained by pyrolysis of silicon tetrachloride (SiCl ₄ ) in a continuous flame at 1000°C in the presence of hydrogen and oxygen. Among the fumed silicas of hydrophilic nature which can be used according to the present invention, mention may be made in particular of those sold by the company Degussa or Evonik Degussa under the trade names Aerosil ^® 90, 130, 150, 200, 300 and 380 or even by the Cabot company under the name Carbosil H5.

AQU PHASE EUSE

The composition according to the present invention comprises an aqueous phase comprising water.

The aqueous phase is preferably present in an amount of at least 75% by weight, preferably at least 80% by weight, more preferably at least 85% by weight, more preferably at least 90% by weight. weight, even more preferably at least 95% by weight, more preferably at least 98% by weight, and more preferably at least 99% by weight based on the weight of the composition.

Preferably, the water is present in an amount of at least 65% by weight, preferably at least 70% by weight, preferably at least 75% by weight, preferably at least 80% by weight, preferably at least 90% by weight, preferably at least 95% by weight, preferably at least 98% by weight, and preferably at least 99% by weight with respect to the composition weight. In a particular embodiment, the aqueous phase represents 100% by weight relative to the weight of the composition.

The aqueous phase can advantageously be present in a content ranging from 65% to 100% by weight, preferably from 70% to 99% by weight, more preferably from 75% to 98% by weight, more preferably from 80% to 95% by weight relative to the total weight of said composition.

Generally, the water is present in an amount ranging from 65% to 95% by weight, preferably from 70% to 90% by weight, more preferably from 75% to 85% by weight relative to the weight of the composition.

This aqueous phase is particularly advantageous for imparting and/or improving the deformability of the microcapsules of the invention.

This aqueous phase advantageously acts as a swelling agent or as a softening agent vis-à-vis the microcapsules without breaking them. The microcapsules are not inert when placed in this aqueous phase, either they swell: their diameter increases significantly with possible softening of the microcapsules, or the microcapsules soften significantly without increasing the diameter, they become more malleable and easier to break when applied to the skin.

The aqueous phase used in the composition according to the invention is capable of acting on the softening kinetics of the microcapsules and more particularly makes it possible to obtain a good balance between the softening kinetics and the hardness.

Consequently, said aqueous phase is particularly advantageous for softening the microcapsules suitable for the present invention, in an appropriate manner, since said aqueous phase plays a role in the softening kinetics of said microcapsules.

This aqueous phase advantageously acts as a swelling agent or as a softening agent vis-à-vis the microcapsules, preferably without breaking them or without triggering dye leakage.

The aqueous phase advantageously comprises water and a water-soluble solvent.

In the present invention, the term “water-soluble solvent” denotes a compound that is liquid at room temperature and miscible with water (miscibility with water greater than 50% by weight at 25° C. and at atmospheric pressure).

The water-soluble solvents which can be used in the composition of the invention can also be volatile.

In another preferred embodiment, the aqueous phase suitable for the present invention comprises at least one polyol, in particular a glycol.

Monoalcohol / Polyol

The composition according to the invention comprises at least one monoalcohol chosen from ethanol, propanol, butanol, isopropanol and isobutanol and may also comprise at least one alcohol chosen from a monoalcohol and a polyol.

A composition of the invention may comprise at least 0.5% by weight, preferably at least 1% by weight, preferably at least 2% by weight, more preferably from 0.5% to 40% by weight, preferably from 3 to 15% by weight, preferably from 2% to 15% by weight, preferably from 2.5% to 10% by weight, preferably from 3% to 8% by weight, preferably from 4 to 8% by weight of monoalcohol and/or polyol relative to the total weight of said composition.

Monoalcohols or lower alcohols

In a particular embodiment, the composition according to the present invention comprises at least one monoalcohol and/or one lower alcohol. Such a compound is of the linear, branched or cyclic, saturated or unsaturated alkyl type, bearing only one -OH function.

Advantageously, the monoalcohols or lower alcohols capable of being used in the present invention are C ₂ -C ₈ monoalcohols, preferably non-cyclic monoalcohols, more preferably C ₂ -C ₅ monoalcohols and preferably _C2 - _C3 .

A composition according to the present invention comprises at least one monoalcohol chosen from ethanol, propanol, butanol, isopropanol and isobutanol and preferably comprises ethanol and/or isopropanol and more preferably at least ethanol.

A composition of the present invention may comprise, in a preferred embodiment, at least 1% by weight, preferably at least 2%, more preferably from 2% to 15%, advantageously from 2.5% to 10% by weight and more preferably from 3% to 8% by weight of monoalcohol and/or lower alcohol relative to the total weight of said composition.

It is also necessary to have compositions containing color-changing microcapsules in a physiological medium comprising a lower alcohol because certain cosmetic ingredients are particularly soluble in hydro-alcoholic media.

In addition, the lower monoalcohols such as ethanol make it possible to dissolve the active agents, in particular the keratolytic agents, such as, for example, salicylic acid and its derivatives.

Certain microcapsules of the prior art disintegrate rapidly in hydroalcoholic media, hence the need for compositions comprising stable color-changing microcapsules in hydroalcoholic media.

Polyols

In a particular embodiment of the invention, the composition according to the invention comprises at least one polyol. For the purposes of the present invention, the term “polyol” must be understood as meaning any organic molecule comprising at least two free hydroxyl groups.

Preferably, a polyol according to the present invention is present in liquid form at room temperature.

Polyols/glycols are moisturizers or humectants.

They may affect the stability of other ingredients in the composition, particularly the prior art microcapsules.

It is therefore necessary to have stable compositions containing color-changing microcapsules in a physiological medium comprising a polyol, in particular a glycol, because these compositions have a notable moisturizing or humectant effect.

This problem is solved by the compositions according to the invention. A polyol that can be used in the invention can be a compound of the linear, branched or cyclic, saturated or unsaturated alkyl type, bearing on each alkyl chain at least two —OH functions, in particular at least three —OH functions and more particularly at least four -OH functions.

The polyols which are advantageously suitable for the formulation of a composition according to the present invention are those containing in particular from 2 to 32 carbon atoms, preferably from 2 to 20 carbon atoms and more preferably from 2 to 16 carbon atoms, advantageously from 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms.

According to another embodiment, a polyol which is suitable for the invention can advantageously be chosen from polyethylene glycols.

According to one embodiment, a composition of the invention may comprise a mixture of polyols.

The polyol may advantageously be chosen from polyhydric alcohols, preferably C ₂ -C ₈ and more preferably C ₃ -C ₆ alcohols. The polyol can be chosen from glycerol, pentaerythritol, trimethylolpropane, ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,3-propanediol, pentylene glycol, hexylene glycol, isoprene glycol, dipropylene glycol, diethylene glycol and diglycerol, and mixtures thereof, glycerol and derivatives thereof, polyglycerols, such as glycerol oligomers, for example diglycerol, and polyethylene glycols, glycol ethers (containing in particular of 3 to 16 carbon atoms) such as (C ₁ -C ₄ ) alkyl ethers of mono-, di- or tripropylene glycol, (C ₁ -C ₄ ) alkyl ethers of mono-, di- or triethylene glycol, and mixtures thereof.

The polyol is chosen in particular from the group consisting of glycerol and glycols, preferably propylene glycol, butylene glycol, pentylene glycol, hexylene glycol, dipropylene glycol, diethylene glycol, ethylhexylglycerin, caprylyl glycol , glycol ethers, preferably mono-, di- or tripropylene glycol of an alkyl ether (C ₁ -C ₄ ) or mono-, di- or triethylene glycol of an alkyl ether ( C ₁ -C ₄ ), and mixtures thereof, more particularly glycerol. According to a preferred embodiment of the invention, said polyol is chosen from ethylene glycol, pentaerythritol, trimethylolpropane, propylene glycol, butylene glycol, glycerol, polyglycerols and polyethylene glycols, and mixtures of those -this.

In a particular embodiment, the polyol is chosen from the group consisting of glycerol and glycols chosen from propylene glycol, butylene glycol, ethylhexylglycerin, caprylyl glycol and mixtures thereof.

According to a particular embodiment, the composition of the invention comprises at least butylene glycol, glycerol or a mixture thereof.

In a preferred embodiment, the composition comprises at least glycerol.

According to a particular embodiment, the composition of the invention comprises glycerol as sole polyol.

Advantageously, the composition of the invention comprises at least 0.5%, preferably from 0.5% to 40% by weight, preferably from 3 to 15% by weight, preferably from 4 to 8% by weight polyol(s) and/or glycols, and preferably glycerol, relative to the total weight of the composition.

In another preferred embodiment, the composition of the present invention comprises at least one mono-alcohol at a concentration of at least 1% by weight, preferably at least 2%, preferably 2% to 15% , advantageously from 2.5% to 10% by weight and better still from 3% to 8% by weight of mono-alcohol relative to the total weight of said composition, and further comprises at least one polyol, preferably a glycol, at a concentration of at least 0.5%, preferably 0.5% to 40% by weight, preferably 3% to 15% by weight, preferably 4% to 8% by weight of polyol(s ) and/or glycols, and preferably glycerol, relative to the total weight of the composition.

SILICONE OILS

According to a preferred embodiment, the composition of the present invention further comprises at least one silicone oil. For the purposes of the present invention, the term "silicone oil" should be understood as an oil chosen from volatile or non-volatile polydimethylsiloxanes (PDMS) bearing a linear or cyclic silicone chain, liquid or pasty at room temperature, in particular cyclopolydimethylsiloxanes (cyclomethicones) such as cyclopentasiloxane and cyclohexadimethylsiloxane; polydimethylsiloxanes comprising alkyl, alkoxy or phenyl groups, pendent or at the end of the silicone chain, these groups containing from 2 to 24 carbon atoms; phenylsilicones, for example phenyltrimethicones, phenyl dimethicones, phenyltrimethylsiloxydiphenylsiloxanes, diphenyl dimethicones, diphenylmethyldiphenyltrisiloxanes or 2-phenylethyltrimethylsiloxy silicates, and polymethylphenylsiloxanes.

In a particular embodiment, the composition of the present invention comprises dimethicone with a viscosity of 5 CST, sold under the trademark Xiamete PMX-200 Silicone Fluid 5CS by Dow Corning, or dimethicone with a viscosity of 10 CST sold branded as Element14 PDMS 10-A by Momentive Performance Materials.

The composition of the invention advantageously comprises less than 10%, preferably less than 5%, preferably less than 2%, preferably less than 1% by weight of silicone oil relative to the weight of the composition. Advantageously, the composition of the invention comprises from 0.01 to 10%, preferably from 0.1 to 5%, more preferably from 0.4 to 1% by weight of silicone oil, based on the total weight of the composition.

Moreover, in a preferred embodiment, the composition of the invention is free of silicone polymers, and more particularly of silicone elastomers. This therefore means that the composition according to the invention comprises less than 1%, preferably less than 0.5%, preferably less than 0.25%, preferably less than 0.1% or less than 0.01% of silicone polymers.

ADDITIONAL COSMETIC INGREDIENTS

The composition according to the invention is cosmetically acceptable, that is to say it contains a physiologically acceptable medium which is non-toxic and suitable for being applied to the keratinous material of human beings.

By “cosmetically acceptable”, within the meaning of the present invention, is meant a composition having an appearance, an odor or a pleasant sensation.

The “physiologically acceptable medium” is generally adapted to the form in which the composition is intended to be packaged.

In particular, the nature and the quantity of the ingredients are suitable for a composition formulated in the form of an aqueous gel.

Depending on the form and purpose of the skin care or makeup preparation, the composition of the invention will comprise, in addition to the microcapsules containing the dye and the salicylic acid compound or a derivative thereof ci, other additional cosmetic ingredient(s) such as selected fillers, additional gelling agents, thickening agents, film-forming agents, polymers, preservatives , additional non-imprisoned colorants (for example: pigments, nacres, etc.), active agents, UV sunscreens, perfumes, humectants, pH regulators and mixtures thereof.

In another particular embodiment, the composition contains nacres. The term "nacres" should be understood as meaning iridescent or non-iridescent colored particles of any shape, specially produced by certain molluscs in their shells or alternatively synthesized, which have a color effect by optical interference.

The nacres can be chosen from pearlescent pigments such as mica coated with an iron oxide, mica coated with bismuth oxychloride, mica coated with titanium oxide or dioxide, mica coated with chromium oxide , mica coated with tin oxide, mica coated with SnO ₂ , mica coated with BaSO ₄ , mica coated with an organic dye and also pearlescent pigments based on bismuth oxychloride. Preferably, the nacres have a white appearance and are preferably formed of mica covered with at least titanium dioxide.

As preferred nacres, we use mica coated with titanium oxide or dioxide.

The pH of the cosmetic composition according to the present invention is preferably in a range from 4.5 to 8, and more preferably between 5.5 and 7.5, and most preferably between 6 and 7. A preferred base for to alter the pH is triethanolamine or potassium hydroxide.

These are routine operations for a person skilled in the art to adjust the nature and the quantity of the additives present in the compositions in accordance with the invention so that the desired cosmetic properties thereof are not affected.

The composition according to the present invention provides a very comfortable feeling during application, and a natural coloration of the skin after application. After application, all these characteristics achieve a very good balance between the perception of the effectiveness of skin care (e.g. hydration) and the effectiveness of makeup (adequate coverage and natural glow). It is best to add a suitable sun protection agent.

Otherwise, the aqueous gel according to the invention can contain at least two different types of microcapsules, for example three different types of microcapsules. The aqueous gels according to the invention can be obtained with a pure and clean appearance of the mass. However, the capsules should release pigment during application without any particulate feel. Skin coloring results are perfectly and evenly provided after application. Additionally, sunscreens can be added into the system and provide additional sun care benefit.

A gel composition according to the invention may be in the form of makeup and/or care compositions for keratinous materials, in particular for the skin or the lips. In particular, a composition according to the invention can be a BB product or a foundation specially intended to be applied to the face or the neck, a product for masking dark circles, a corrective product, a tinted cream, a colored composition for care or make-up for the skin, in particular for the face or the body, or an after-sun composition. In a preferred embodiment, a composition according to the present invention is a leave-in composition: the composition is not intended to be rinsed off after application to the skin.

A gel composition according to the invention may comprise at least one cosmetic or dermatological active agent. It can then be used as a care or make-up base for keratinous materials, in particular the skin.

In another preferred embodiment, the composition according to the present invention is not contained in a dispenser comprising a pump. This solution is advantageous because it avoids the risk of rupture of the microcapsules. Indeed, during the use of such a dispenser, said microcapsules could be crushed before their application on the keratinous materials.

These compositions are prepared according to the usual methods.

Compositions of this type can be in the form of a care or makeup product for the face and/or the body, and can be packaged, for example, in a jar or in a tube.

DESCRIPTION OF DRAWINGS

The is a diagram illustrating a typical structure of a color-changing microcapsule of the present invention, in which A represents a core and B, C, D and E are different layers concentrically surrounding said core.

The represents a schematic diagram illustrating the core-shell structure of the color-changing microcapsules B prepared according to Example 2 described below.

EXAMPLES

Example 1 : Preparation of a microcapsule A having an interior coating of brown color and an exterior coating of white color

Mannitol (spray dried mannitol: Pearitol 100SD) is used as the core.

To a mixed solution of 3200.0 g of ethanol, 120.0 g of ceramide (Ceramide PC 104) and 120.0 g of hydrogenated lecithin (Lipoid S 100-3) are added and completely dissolved at 40°C. To the resulting mixture, 1260.0 g of yellow iron oxide, 252.0 g of red iron oxide and 45.36 g of black iron oxide are added and well dispersed with a homogenizer to prepare a coating solution internal color.

347.70 g of mannitol were introduced into a fluidized bed coating system (Glatt GPCG 1, bottom spray) in the form of grains and coated at 500㎖/h of the solution feed rate. inner color coating to obtain particles having a mannitol core coated with an inner color layer.

Then, to a mixed solution of 1440.0 g of ethanol, 36.0 g of ceramide and 36.0 g of hydrogenated lecithin are added and dissolved at 40°C. To the resulting mixture, 600.0 g of titanium dioxide particles are added and well dispersed using a homogenizer to prepare a coating solution of titanium dioxide particles.

Coating with the resulting titanium dioxide particle coating solution is carried out by a fluidized bed process to obtain particles having an inner color layer coated with a layer of titanium dioxide particles.

Then, 300.0g of shellac is dissolved in 3000g of ethanol to prepare an outer layer coating solution, which is applied to the above layer of titanium dioxide particles to obtain a color microcapsule changeable having a layer of titanium dioxide particles coated with an outer layer.

Example 2 : Preparation of a microcapsule B having an interior coating of brown color and an exterior coating of white color

Using the ingredients and contents described in the table below, a color-changing microcapsule having a core and 2 layers as shown in the is prepared by a fluidized bed process (according to a process similar to that of Example 1):

(1) Ingredients: Kernel grain - inner color layer - TiO ₂ particle layer

Core Mannitol 13.7% ^1st layer Sunpuro Yellow 17.36% Sunpuro Red 3.67% Black Sunpuro 0.61% Lecithin 0.20% corn starch binder 1.0% ^2nd layer Titanium dioxide qsp, 100% Lecithin 0.3% corn starch binder 1.5%

The percentages indicate the percentage by weight relative to the total weight of the microcapsule.

Example 3 : Preparation of aqueous gels comprising a microcapsule having an interior coating of brown color and an exterior coating of white color

The following aqueous gel compositions A, B and C according to the invention were prepared.

A (invent-tion) A1 (comparative) B (invent-tion) B1 (comparative) C (invent-tion) C1 (comparative) YELLOW 5 / CI 19140 0.0010 0.0010 0.0010 0.0010 0.0010 0.0010 BLUE 1 / CI 42090 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 NIACINAMIDE 3 3 3 3 3 3 DIMETHICONE 0.5 0.5 0.5 0.5 0.5 0.5 ALCOHOL DENAT. 3 3 3 3 3 3 GLYCERINE 7 7 7 7 7 7 TETRASODIUM GLUTAMATE DIACETATE 0.2375 0.2375 0.2375 0.2375 0.2375 0.2375 PHENOXYETHANOL 0.6 0.6 0.6 0.6 0.6 0.6 CROSS-LINKED POLYMER OF SODIUM-2 ACRYLATES (and) WATER (and) SILICA ⁽¹⁾ 1 1 CARBOMER ⁽²⁾ 1 1 TRIETHANOLAMINE 1 1 SODIUM POLYACRYLATE ⁽³⁾ 1.5 1.5 KPT Magic 30-BW0105 3 3 3 3 3 3 CAPRYLOYL SALICYLIC ACID 0.3 0.3 0.3 WATER / AQUA Qsp. Qsp. Qsp. Qsp. Qsp Qsp

(1) AQUAKEEP 10SH-NFC marketed by SUMITOMO SEIKA

(2) CARBOPOL ULTREZ 10 POLYMER sold by LUBRIZOL

(3) COSMEDIA SP marketed by BASF

The resulting aqueous gels are easy to handle and spread on the skin.

E capacity assessment broadcast color :

The diffusion of the color of the compositions according to the invention is evaluated visually by applying the compositions of Table 1 to the skin. 10µg of composition are applied to an area 4cm in diameter on the testers' forearm. The composition is then rubbed during application by rotations of 10 fingers.

The compositions were tested immediately after their preparation and their mixing (T0), after 6 hours of storage at ambient temperature (T6), and after 16 hours of storage at ambient temperature (T16).

The results are as follows:

Compositions A, B, C (according to the invention) Compositions A1, B1, C1 (comparative) T0 Color diffusion +/- Color diffusion +/- T6 Diffusion of color + Color diffusion +/- T16 Diffusion of color ++ Color diffusion +/-

Compositions A, B and C made it possible to obtain a release of the color on application, while preserving the stability of the microcapsules and ensuring good sensoriality on the skin, while the comparative compositions A1, B1 and C1 n did not allow to obtain a release of the color on the skin. In addition, at T6, no sensation of discomfort was felt during the application of the compositions according to the invention, whereas a sensation of "friction" was felt at T0 or with the comparative compositions, resulting mainly because the outer layer of the microcapsules is not softened enough. It also results in absence/failure of color release, for example failure of pigment release and spreading of the microcapsules on the skin, resulting from failure to break/break the microcapsules during application.

Claims (10)

Color-changing composition for caring for and/or making up keratinous materials in the form of an aqueous gel comprising at least:
a) an aqueous phase;
b) microcapsules containing releasable dye(s), said microcapsules comprising:
- a core comprising organic matter,
- at least one laminated coating surrounding said core, the laminated coating comprising at least one polymer, at least one colorant, and advantageously at least one lipid-based material;
c) a salicylic acid compound and/or a derivative thereof;
d) a hydrophilic gelling agent chosen from synthetic polymeric gelling agents, natural or naturally occurring polymeric gelling agents, mixed silicates and fumed silicas, and mixtures thereof; and
e) a monoalcohol chosen from ethanol, propanol, butanol, isopropanol and isobutanol. A color-changing composition according to claim 1, wherein:
- the core of microcapsules containing releasable dye(s), comprises at least one monosaccharide or its derivatives such as said organic material, in particular a monosaccharide-polyol advantageously chosen from mannitol, erythritol, xylitol , sorbitol and mixtures thereof, preferably mannitol; and
- the stratified coating surrounding said core comprises at least one (several) hydrophilic polymer(s) chosen from the group consisting of polysaccharides and derivatives, preferably those comprising a type of ose or several types of ose, preferably several types of ose comprising at least D-glucose units, in particular starch and derivatives, cellulose or derivatives, and more preferably starch and derivatives;
and in which said color-changing composition comprises from 0.1% to 25% by weight, preferably from 0.5% to 15% by weight and in particular between 1 and 10% by weight of microcapsules relative to the total weight of said composition. Color-changing composition according to any one of the preceding claims, in which the said salicylic acid compound is advantageously chosen from salicylic acid and the compounds of formula (I) below:
(I)
in which :
- the radical R denotes a saturated, linear, branched or cyclic aliphatic chain, containing from 2 to 22, preferably from 3 to 11, carbon atoms; an unsaturated chain containing from 2 to 22, preferably from 3 to 17, carbon atoms comprising one or more optionally conjugated double bonds; an aromatic nucleus linked to the carbonyl radical directly or via saturated or unsaturated aliphatic chains containing from 2 to 7 carbon atoms; said groups possibly being substituted by one or more substituents, identical or different, chosen from (a) halogen atoms, (b) the trifluoromethyl group, (c) hydroxyl groups in the free form or esterified with an acid containing 1 with 6 carbon atoms, or (d) a carboxyl function in the free form or esterified with a lower alcohol containing from 1 to 6 carbon atoms;
- R' is a hydroxyl group;
- and as well as the salts thereof derived from an inorganic or organic base. Color-changing cosmetic composition according to any one of the preceding claims, in which the said compound of formula (I) is chosen from the list consisting of 5-n-octanoylsalicylic acid (or capryloylsalicylic acid); 5-n-decanoylsalicylic acid; 5-n-dodecanoyl-salicylic acid; 5-n-heptyloxysalicylic acid, and corresponding salts thereof. A color-changing cosmetic composition according to any preceding claim, wherein the amount of said salicylic acid compound is in a range from 0.1% to 10% by weight, preferably from 0.15% to 5 % by weight and preferably ranging from 0.20% to 3% by weight, and most preferably ranging from 0.25% to 0.5% by weight, relative to the total weight of the composition. Color-changing cosmetic composition according to any one of the preceding claims, in which the said hydrophilic gelling agent is a natural or naturally occurring gelling agent, chosen from among starchy polysaccharides and non-starchy polysaccharides, or a synthetic polymeric gelling agent, chosen from particulate synthetic polymeric gelling agents, non-particulate synthetic polymeric gelling agents comprising associative polymers, polyacrylamides and polymers and copolymers of 2-acrylamido-2-methylpropanesulfonic acid and modified or unmodified carboxyvinyl polymers, and wherein said hydrophilic gelling agent is present in an amount of 0.001% to 20%, 0.01% to 10% by weight, preferably 0.1% to 5% by weight, more preferably 0.5% to 2.5 % by weight, and better still from 1% to 2% by weight, relative to the total weight of the composition. Color-changing cosmetic composition according to any one of the preceding claims, in which the said monoalcohol is present in an amount of at least 0.5% by weight, preferably at least 1% by weight, preferably at least least 2% by weight, more preferably 0.5% to 40% by weight, preferably 3% to 15% by weight, preferably 2% to 15% by weight, preferably 2.5% to 10% by weight, preferably from 3% to 8% by weight, preferably from 4% to 8% by weight of monoalcohol relative to the total weight of said composition. Color-changing cosmetic composition according to any one of the preceding claims, further comprising at least one polyol chosen from the group consisting of glycerol and glycols, preferably propylene glycol, butylene glycol, pentylene glycol, hexylene glycol, dipropylene glycol, diethylene glycol, ethylhexylglycerin, caprylyl glycol, glycol ethers, preferably mono-, di- or tripropylene glycol of an alkyl ether (C ₁ -C ₄ ) or mono-, di- or triethylene glycol of a (C ₁ -C ₄ ) alkyl ether, and mixtures thereof, more preferably the polyol is glycerol, wherein said at least one polyol is present in an amount of at least 0.5%, preferably 0.5% to 40% by weight, preferably 3 to 15% by weight, preferably 4 to 8% by weight of polyol(s ) and/or glycols relative to the total weight of the composition. Color-changing cosmetic composition according to any one of the preceding claims, additionally comprising at least one cosmetic and/or dermatological active ingredient. Cosmetic process for caring for and/or making up keratinous materials, comprising the application to said keratinous materials, in particular to the skin, of a composition as defined according to any one of the preceding claims.