WO2004006872A1

WO2004006872A1 - Cosmetic use of a polymer comprising lcst units

Info

Publication number: WO2004006872A1
Application number: PCT/EP2003/008484
Authority: WO
Inventors: Véronique Chevalier; Florence L'alloret
Original assignee: L'oréal
Priority date: 2002-07-16
Filing date: 2003-07-15
Publication date: 2004-01-22
Also published as: AU2003250199A1

Abstract

The invention concerns the cosmetic use, in a composition comprising a physiologically acceptable medium, as an agent for matifying the skin and/or for concealing blemishes and/or for camouflaging pores, of at least one hydrosoluble or hydrodispersible polymer comprising hydrosoluble or hydrodispersible units and LOST units, the said LCST units having, in water, a demixing temperature (or cloud point) of 5°C to 40°C at a concentration by weight of 1%, the said composition being free of any other compound having an optical effect selected from fillers, ,nacres, pigments, matifying polymers and tightening agents. The invention also concerns the use, in the cosmetic treatment for greasy or combination skin, of a composition containing the said polymer in a physiologically acceptable medium, excluding any other compound having an optical effect.

Description

COSMETIC USE OF A POLYMER COMPRISING LOST UNITS

The invention concerns the cosmetic use, in a composition comprising a physiologically acceptable medium, as an agent for matifying the skin and/or for concealing blemishes and/or for camouflaging pores, of at least one hydrosoluble or hydrodispersible polymer comprising LCST units, the said composition being free of any other compound having an optical effect.

For the uses described above, its use as an agent for matifying the skin as described above is of particular application to a greasy or combination skin; its use for concealing blemishes is of particular application to a skin having blemishes, wherein the composition is more particularly for use on young or tired skin; and its use for camouflaging the pores is of particular application to skin having dilated pores .

The invention also concerns the use, in the cosmetic treatment for greasy or combination skin, of a composition containing the said polymer in a physiologically acceptable medium, the composition excluding any other compound having an optical effect. Skin shine, often connected with substantial sebum secretion, and its unevenness due to superficial problems such as wrinkles, dilated pores or colour variations such as blemishes, are problems that are encountered by women of all ages. Unevenesses in the complexion can also be due to poor makeup staying power; its appearance tends to deteriorate during the course of the day.

Means used until now to reduce skin shine have essentially consisted of using fillers such as talc, starch, mica, silica, nylon powders, polyethylene powders, poly-beta-alanine and polymethyl (meth) acrylate powders. Those fillers, however, suffer from the disadvantage of giving the skin an unnatural powdery appearance which may even accentuate any problems.

Further, those compositions generally cause the skin to dry out in the long term. Still further, the matte effect only lasts a short time.

Yet still further, the said matifying compositions require the use of gelling agents in order to produce textures that are easy to apply and which feel pleasant. However, the viscosity of conventional cosmetic gelling agents, which are constituted by acrylic polymers, xanthan gum or starch, reduces with rising temperatures. Thus, any composition which is a fluid at 20°C remains a fluid at the temperature of the skin (32°C) , which does not result in good properties for application. Moreover, compositions that gel at skin temperature, which are easier to apply, also have to be gelled at 20°C; thus, the accessible range of textures for matifying compositions is limited. It thus would appear to be necessary to identify compounds that can modify the appearance of the skin by dint of an optical effect, which are not drying and which do not irritate the skin, and which can expand the range of galenical supports and textures accessible to the compositions containing them.

The Applicant has discovered that certain thermogelling polymers can satisfy this need provided that they not only have the property of gelling the aqueous phase of cosmetic compositions under the effect of a rise in temperature, but also have the property of diffusing light at the skin surface.

The said thermogelling polymers are hydrosoluble or hydrodispersible polymers comprising hydrosoluble or hydrodispersible units and LCST units. Polymers of this type have already been described in the following documents: D. HOURDET et al . , Polymer, 1994, vol. 35, n°12, pages 2624-2630; F. L'ALLORET et al., Coll. Polym. Sci., 1995, vol. 273, n°12, pages 1163-1173; F. L'ALLORET et al . , Revue de 1 ' Institut

Frangais du Petrole, 1997, vol. 52, n°2, pages 117-128; and European patents EP-A-0 583 814 and EP-A-0 629 649. The said polymers have already been described as being useful in ensuring the stability of cosmetic dispersions when subjected to temperature variations in the range 4°C to 50°C (FR-A-2 819 415, unpublished) . They—are also known to- cancel or reduce the superficial adhesion power of a film or deposit obtained from a composition having an optical effect containing the said polymer and a further agent having an optical effect selected from fillers, nacres, pigments, matifying polymers and tightening agents (FR- A-2 819 397, unpublished) . The Applicant has also demonstrated their capacity for smoothing fine lines and wrinkles by the tightening effect. In contrast, to the Applicant's knowledge, the use of thermogelling agents of the prior art without any other agent having an optical effect has never been proposed for modifying the appearance of the skin and in particular for matifying it. This matifying property produced by the polymers used in accordance with the invention is particularly surprising since the majority of hydrosoluble polymers have the contrasting tendency of forming shiny deposits on the skin. Thus, the present invention concerns the cosmetic use, in a composition comprising a physiologically acceptable medium, as an agent for matifying the skin and/or for concealing blemishes and/or for camouflaging pores, of at least one hydrosoluble or hydrodispersible polymer comprising hydrosoluble or hydrodispersible units and LCST units, the _said LCST units having, in water, a demising temperature (or cloud point) of 5°C to 40°C at a concentration by weight of 1%, the said composition being free of any other compound having an optical effect selected from fillers, nacres, pigments, matifying polymers and tightening agents .

The invention also concerns the use, in the cosmetic treatment for greasy or combination skin, of a composition containing, in a physiologically acceptable medium, at least one hydrosoluble or hydrodispersible polymer comprising hydrosoluble or hydrodispersible units and LCST units, the said LCST units having, in water, a demixing temperature (or cloud point) of 5°C to 40°C at a concentration of 1% by weight, the said composition being free of any other compound having an optical effect selected from fillers, nacres, pigments, matifying polymers and tightening agents.

One major advantage of the polymers of the invention is that their optical properties are retained, or even enhanced (as indicated in Example 2 below) as the temperature is raised, in contrast to conventional matifying agents which lose effectiveness primarily due to perspiration. This advantage renders compositions containing them highly suitable for use in warm climates. In accordance with the invention, polymers with a gelling temperature of 5°C to 50°C, preferably 15°C to 40°C, at a concentration by weight " in water of 2%, are preferably used. This characteristic is particularly advantageous, as it provides access to a wide range of textures for cosmetic compositions . As stated above, the said polymers have gelling properties in the aqueous phase that are stimulated by a rise in temperature. Thus, the polymers of the invention provide access to cosmetic compositions with a wide range of textures, which has not been the case with prior art compositions which, in addition to matifying agents, astringents or conventional blemish concealing agents, require the addition of gelling agents. The polymers used in the context of the present invention can be in the form of block polymers comprising alternating hydrosoluble or hydrodispersible units and LCST units, or in the form of graft polymers comprising a backbone, which is optionally cross- linked, formed from hydrosoluble or hydrodispersible units and carrying grafts constituted by LCST units, or vice versa.

The hydrosoluble or hydrodispersible units of the said polymers are. preferably units that are soluble in water at 5°C to 80°C in an amount of at least 10 g/1, preferably at least 20 g/l. However, it is also possible to use hydrosoluble or hydrodispersible units which do not necessarily possess the solubility mentioned above, but which in a 1% by weight aqueous solution, at 5°C to 80°C, can produce a macroscopically homogeneous and transparent solution, i.e., with a maximum light transmittance of at least 85%, preferably at least 90% at any wavelength in the range 400 nm to 800 nm, through a 1 cm thick sample. These hydrosoluble or hydrodispersible units do not possess an LCST type demixing temperature on heating. These hydrosoluble or hydrodispersible units can be obtained by radical polymerization of vinyl monomers or by polycondensation, or they can be constituted by natural polymers or existing modified natural polymers .

Examples of hydrosoluble monomers and their salts which may be used to completely or partially form the said hydrosoluble or hydrodispersible units by polymerization, used alone or as a mixture, are as follows :

(meth) acrylic acid;

- vinylsulphonic acid;

- (meth) allylsulphonic acid; - vinylphosphonic acid;

- methyl vinylimidazolium chloride; (meth) acryla id ;

- 2-vinylpyridine, 4-vinylpyridine;

- maleic acid and maleic anhydride;

- crotonic acid; - itaconic acid;

- vinyl alcohol;

- N-vinyllactams comprising a cyclic alkyl group containing 4 to 9 carbon atoms, such as N- vinylpyrrolidone, N-vinylcaprolactam or N-butyrolactam;

- hydrosoluble styrene derivatives, in particular styrene sulphonate;

- dimethyldiallyl ammonium chloride;

- N-vinylacetamide and N-methyl,N-vinylacetamide; - N-vinylformamide and N-methyl, N-vinylformamide;

- vinyl monomers with formula (I) below:

in which: - R is selected from H, -CH₃, -C₂H₅ or -C₃H₇, and

- X is selected from: alkyl -OR' type oxides, in which R' is a saturated or unsaturated, linear or branched hydrocarbon radical containing 1 to 6 carbon atoms, substituted with at least one group selected from halogen atoms (iodine, bromine, chlorine, fluorine) ; sulphonic (~S0₃ ^~) , sulphate (-SO₄ ^") , phosphate (-P0₄H₂ ^") ; hydrosyl (-OH) ; ether (-0-) ; primary amine (-NH₂) ; secondary amine (-NHRi) , tertiary amine (- Ri ₂) or quaternary amine (-N⁺RιR₂ 3) groups in which R_1# R₂ and R₃ independently represent saturated or unsaturated, linear or branched hydrocarbon radical containing 1 to 6 carbon atoms, provided that the sum of the carbon atoms of R' + Ri + R₂ + R₃ does not exceed 7 ; and -NH₂, -NHR₄ and -NR₄R5 groups in which R₄ and R₅ independently represent saturated or unsaturated, linear or branched hydrocarbon radicals containing 1 to 6 carbon atoms, provided that the total number of carbon atoms of R₄ + R₅ does not exceed 7, the said R₄ and R₅ being substituted with at least one group selected from halogen atoms (iodine, bromine, chlorine, fluorine) ; hydroxyl (-OH) ; ether (-0-) ; sulphonic (-S0₃ ^") ; sulphate

(-SO₄ ^") ; phosphate (-P0₄H₂ ^~) ; primary amine (-NH₂) ; secondary amine (-NHRi) , tertiary amine (-NR3R2) and/or quaternary amine (-N⁺RιR₂R3) groups in which R-_L, R₂ and R₃, independently represent a saturated or unsaturated, linear or branched hydrocarbon radical containing 1 to 6 carbon atoms, provided that the sum of the carbon atoms of R₄ + R₅ + R_x + R₂ + R3 does not exceed 7.

Examples of hydrosoluble monomers with formula (I) that can be cited are glycidyl (meth) acrylate, hydroxyethyl methacrylate, ethylene glycol, diethyleneglycol or polyalkyleneglycol (meth) acrylates, N,N-dimethylacrylamide, acrylamido-2- methylpropane sulphonic acid (AMPS), (meth) acrylamido propyl trimethyl ammonium chloride (APTAC and MAPTAC) and quaternized dimethylaminoethyl methacrylate (MADAME) .

More monomers that can be used to partially or completely constitute the hydrosoluble or hydrodispersible units that can be cited include hydrophobic monomers, the said monomers being copolymerized with at least one hydrosoluble monomer in a quantity such that the resulting units are hydrosoluble or hydrodispersible, the said hydrophobic monomers being selected from the following monomers : - styrene and its derivatives such as 4- butylstyrene, alpha-methylstyrene or vinyltoluene;

- vinyl acetate with formula CH₂=CH-OCOCH₃.

- vinylethers with formula CH₂=CHOR₆, in which R₆ is a saturated or unsaturated, linear or branched hydrocarbon radical containing 1 to 6 carbon atoms; - acrylonitrile;

- caprolactone;

- vinyl chloride and vinylidene chloride;

- silicone derivatives such as methacryloxypropyltris (trimethylsiloxy) silane and silicone methacrylamides;

- hydrophobic vinyl monomers with formula (II) below:

H₂C CR₇

CO (ii)

in which:

- R₇ is selected from H, -CH₃, -C₂H₅ and C₃H₇,

- Xi is selected from:

- -OR₈ type alkyl oxides in which R₈ is a saturated or unsaturated, linear or branched hydrocarbon radical containing 1 to 22 carbon atoms;

- NH₂, -NHR₉ and -NR₉Rι₀ groups in which R9 and R₁₀ independently form saturated or unsaturated, linear or branched hydrocarbon radicals containing 1 to 22 carbon atoms, provided that the total number of carbon atoms of R₉ + R₁₀ does not exceed 23.

Examples of the said monomers that can be cited are methyl methacrylate, ethyl methacrylate, n- butyl methacrylate, tertiαbutyl methacrylate, cyclohexyl acrylate, isobornyl acrylate and 2- ethylhexyl acrylate.

The hydrosoluble or hydrodispersible units can if necessary be partially or completely neutralized by a mineral or organic base selected from sodium, ammonium, lithium, calcium or magnesium salts or ammonium salts substituted with 1 to 4 alkyl groups containing 1 to 15 carbon atoms, or from mono-, di- or triethanolamine, aminoethylpropanediol, N-methyl- glucamine, basic amino acids such as arginine or lysine, and mixtures thereof.

It should also be noted that the backbone of the graft polymers can be cross-linked by the action of at least one cross-linking agent selected from compounds with an olefinic unsaturation routinely used to cross-link polymers obtained by radical polymerization. Examples of such agents that can be cited are divinylbenzene, diallyl ether, dipropyleneglycol-diallylether, polyglycol- diallylethers, triethyleneglycol-divinylether, hydroquinone-diallyl-ether, tetrallyl-oxethanoyl, allyl or vinylether derivatives of polyfunctional alcohols, tetraethyleneglycol diacrylate, triallylamine, trimethylolpropanediallylether, tetraallyloxyethane, methylene-bis-acrylamide, allyl ethers of sugar series alcohols, -allyl methacrylate, trimethylol propane triacrylate (TMPTA) and mixtures thereof. Preferably, a non-cross-linked graft polymer backbone is employed. The following polycondensates and natural polymers or modified natural polymers that can completely or partially constitute the hydrosoluble or hydrodispersible units can be cited:

- hydrosoluble polyurethanes,

- xanthan gum, in particular that sold under the trade names Keltrol T and Keltrol SF from Kelco, or Rhodigel SM and Rhodigel 200 from Rhodia;

- alginates (Kelcosol from Monsanto) and their derivatives such as propyleneglycol alginate (Kelcoloid LVF from Kelco) ; - cellulose derivatives, in particular carboxymethylcellulose (Aquasorb A500 Hercules) , hydroxypropylcellulose, hydroxyethylcellulose and quaternized hydroxyethylcellulose,

- galactomannanes and their derivatives such as Konjac gum, guar gum, hydroxypropylguar, hydroxypropylguar modified by sodium methylcarboxylate groups (Jaguar XC97-1, Rhodia) and guar hydroxypropyl trimethyl ammonium chloride, and - polyethylene-imine. Preferably, the molar mass of the hydrosoluble or hydrodispersible units is 1000 g/mol to 10 000 000 g/mol when they constitute the hydrosoluble backbone of a graft polymer. These hydrosoluble or hydrodispersible units preferably have a molar mass of 500 g/mol to 500 000 g/mol when they constitute a block of a multiblock polymer or when they constitute the grafts of a graft polymer. The LCST units of the polymers of the invention can be defined as units with a solubility in water that is modified above a certain temperature. They are units with a demixing temperature on heating (or cloud point) defining their solubility zone in water. The minimum demixing temperature obtained as a function of the polymer concentration is termed the lower critical solution temperature (LCST) . For each polymer concentration, a demixing temperature is observed on heating; it is higher than the LCST, which is the minimum point on the curve. Below that temperature, the polymer is soluble in water; above that temperature, the polymer loses water solubility. The expression "soluble in water at temperature T" means that units have a solubility at T of at least 1 g/1, preferably at least 2 g/1. The LCST can be measured visually. As an example, the temperature at which an aqueous solution becomes cloudy can be determined visually provided that at that temperature, the solution becomes more opaque or loses transparency. In general, a transparent composition will have a maximum light transmittance of at least 85%, preferably at least 90% at any wavelength in the range 400 nm to 800 nm through a 1 cm thick sample. Transmittance can be measured by placing a 1 cm thick sample in the light beam from a spectrophotometer operating in the wavelengths of the light spectrum.

The LCST units of the polymers of the invention can be constituted by one or more of the following polymers:

- polyethers such as polyethylene oxide (POE) , polypropylene oxide (POP) , and random copolymers of ethylene oxide (OE) and propylene oxide (OP) ,

- polyvinylmethylethers, - polymeric and copolymeric N-substituted derivatives of acrylamide having an LCST,

- polyvinylcaprolactam and vinyl caprolactam copolymers .

Preferably, the LCST units are constituted by random copolymers of ethylene oxide (OE) and propylene oxide (OP) represented by the formula: (OE)_m(OP)_a in which m is a whole number from 1 to 40, preferably 2 to 20, and n is a whole number from 10 to 60, preferably 20 to 50. Preferably, the molar mass of the said LCST units is 500 to 5300 g/mol, more preferably 1500 to 4000 g/mol.

It has been shown that the random distribution of the OE and OP moieties results in the existence of a lower critical demixing temperature beyond which macroscopic phase separation is observed. This behaviour is different from that of block OE/OP copolymers, which micellize beyond a critical temperature termed the micellization temperature (aggregation on a microscopic scale) .

The LCST units can thus be in the form of random copolymers of ethylene oxide and propylene oxide, which may be aminated, in particular monoa inated, diaminated or triaminated. Commercially available LCST units that can be cited are copolymers sold under the trade name Jeffamine by HUNTSMAN, in particular Jeffamine XTJ-507 (M-2005) , Jeffamine D-2000 and Jeffamine XTJ-509 (or T-3000) .

The LCST units can also be in the form of random OE/OP copolymers with OH extremities such as those sold by Clariant under the trade name Polyglycols P41 and Bll.

Advantageous examples of polymers with LCST units that can be used in the present invention are polymeric and copolymeric N-substituted derivatives of acrylamide with an LCST as well as poly N- vinylcaprolactam and N-vinylcaprolactam copolymers. Examples of N-substituted derivatives of acrylamide that can be cited are poly-N-isopropyl acrylamide, poly-N-ethyl acrylamide and copolymers of N-isopropyl acrylamide or N-ethyl acrylamide and a vinyl monomer with formula (I) or (II) given above, or a monomer selected from (meth) acrylic acid, vinylsulphonic acid, (meth) allylsulphonic acid, maleic acid and maleic anhydride, vinylphosphonic acid, crotonic acid, itaconic acid, (meth) acrylamide, vinylpyridine, vinyl alcohol, N-vinyllactams such as N- vinylpyrrolidone, styrene and its derivatives, dimethyldiallyl ammonium chloride, N-vinylacetamide, N- methyl, N-vinylacetamide, N- inylformamide, N- methylvinylformamide, vinylethers and vinyl acetate derivatives, acrylonitrile, caprolactone, vinyl chloride and vinylidene chloride.

The molar mass of the N-substituted acrylamide polymers and copolymers is preferably 1000 g/mol to 500 000 g/mol. These polymers can be synthesized by radical polymerisation using a pair of initiators such as aminoethanethiol hydrochloride in the presence of potassium persulphate to obtain oligomers with one reactive amino-containing extremity.

Examples of N-vinylcaprolactam copolymers that can be cited are copolymers of N-vinylcaprolactam and a vinyl monomer with formula (I) or (II) given above, or a monomer selected from (meth) acrylic acid, vinylsulphonic acid, (meth) allylsulphonic acid, maleic acid, maleic anhydride, vinylphosphonic acid, crotonic acid, itaconic acid, (meth) acrylamide, vinylpyridine, vinyl alcohol, N-vinyllactams such as N- vinylpyrrolidone, styrene and its derivatives, dimethyldiallylammonium chloride, N-vinylacetamide, N- methyl-N-vinylacetamide, N-vinylformamide, N- methylvinylformamide, vinyl acetate, vinylethers, acrylonitrile, caprolactone, vinyl chloride and vinylidene chloride. The molar mass of the said polymers is preferably 1000 g/mol to 500 000 g/mol. The said polymers can be synthesized by radical polymerization using a pair of initiators such as aminoethanethiol hydrochloride in the presence of azobis-isobutyronitrile to obtain oligomers with one reactive amino-containing extremity. The proportion by weight of the LCST units in the final polymer is preferably 5% to 70%, in particular 20% to 65%, and particularly 30% to 60% by weight with respect to the final polymer. As defined above, the demixing temperature of the LCST units on heating is preferably 5°C to 40°C, more preferably 10°C to 35°C for a concentration by weight of LCST units in water of 1%. The demixing temperatures are determined by UV-visible spectroscopy, by measuring the absorbance of aqueous solutions comprising 1% by weight of the said LCST units at a wavelength of 500 nm. The demixing temperature is identified as the temperature at which the absorbance of the solution is equal to 2. The polymers used in the context of the present invention can readily be prepared by the skilled person using various methods such as grafting, copolymerization, coupling or living polymerization methods . As an example, when the final polymer is in the form of a graft polymer with a hydrosoluble backbone with LCST side units, it can be prepared by grafting LCST units having at least one reactive extremity, for example aminated, onto a hydrosoluble polymer forming the backbone, the said backbone carrying a minimum of 10% (in mols) of reactive groups such as carboxylic acid functions . This reaction can be carxied out in the presence of a carbodiimide such as dicyclohexylcarbodiimide or l-(3- dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride, in a solvent such as N-methylpyrrolidone or water. A further possibility for preparing graft polymers consists of copolymerizing an LCST macromonomer (the unit described above with an unsaturated extremity) , for example, with a hydrosoluble vinyl monomer such as acrylic acid or vinyl monomers with formula (I) cited above.

When the final polymer is in the form of a block polymer, it can be prepared by coupling between hydrosoluble or hydrodispersible units and LCST units having complementary reactive sites at each extremity. It is also possible to prepare the said polymers by living polymerization of the anionic or cationic type or by controlled radical polymerization. The said latter synthesis process can be carried out using different methods such as atom transfer radical polymerization, ATRP, a radical method such as that using nitroxides or a radical addition-fragmentation chain transfer such as the MADIX process (macromolecular design via the interchange of xanthate) . The said processes can be employed to produce hydrosoluble blocks and LCST blocks of the polymers used in -the invention. They can also be used to synthesize just one of the two types of polymer blocks used in the invention, the other block being introduced into the final polymer via the initiator used or by a coupling reaction between the hydrosoluble blocks and the LCST.

As indicated above, the composition of the invention containing the polymer with LCST units described above does not include any other compound having an optical effect from one of the following categories: fillers, nacres, pigments, matifying polymers and tightening agents.

The absence of such compounds in the composition used in accordance with the invention not only surprisingly does not perturb the optical properties of the composition when it is applied to the skin, but also offers the cosmetic products formulator the possibility of formulating transparent compositions, which cannot be produced when using fillers or latex, for example, which give such compositions a white appearance.

The term "fillers" encompasses colourless or white, mineral or organic, lamellar or non lamellar, cylindrical particles, which are capable of providing body or stiffness to the composition and or softness, mattness and uniformity to the makeup. Fillers that can be.ci-ted are talc, mica, silica, boron nitride, bismuth oxychloride, kaolin, nylon powders such as nylon-12 (Orgasol sold by Atochem) , polyethylene powders, Teflon (polytetrafluoroethylene powders) , polyurethane powders, polystyrene powders, polyester powders, starch, which may be modified, microspheres of copolymers such as those sold by Nobel Industrie under the trade name Expancel, microsponges such as Polytrap sold by Dow Corning, silicone resin microbeads such as those sold by Toshiba under the trade name Tospearl, precipitated calcium carbonate, magnesium carbonate and bicarbonate, hydroxyapatite, hollow silica microspheres (Silica Beads from Maprecos) , glass or ceramic microcapsules, fibres composed, for example, of polyamide 6-6, metal soaps derived from organic carboxylic acids containing 8 to 22 carbon atoms, preferably 12 to 18 carbon atoms, for example zinc, magnesium or lithium stearate, zinc laurate, magnesium myristate, and mixtures thereof. The term "nacres" means iridescent particles that reflect light . Nacres that can be envisaged include natural nacre (mother of pearl) , mica coated with titanium oxide, iron oxide, natural pigment or bismuth oxychloride, along with coloured mica titanium. The term "pigments" includes mineral or organic white or coloured particles, which are insoluble in the medium _and are capable of colouring and/or opacifying the composition. They may be white or coloured, mineral and/or organic, of the usual size or nanometric. Mineral pigments and nanopig ents that can be cited include titanium, zirconium or cerium dioxides, also zinc, iron or chromium oxides, nanotitaniums (titanium dioxide nanopigments) , nanozincs (zinc oxide nanopigments) , and iron blue. Organic pigments that can be cited are carbon black and lakes such as calcium, barium, aluminium or zirconium salts, acid dyes such as halogeno-acid dyes, azoic dyes or anthraquinone dyes.

The term "matifying polymers" means any polymer in solution, in dispersion or in the form of particles which prevents skin shine and unifies the complexion. More precisely, the term "matifying polymer" means a compound which, when introduced into a cosmetic composition applied to a rubber support in an amount of 2 mg/cm², results in a reduction in the ratio of specular to diffuse reflections measured using a gonioreflectometer at 20°C, of at least 5% with respect to the same composition not containing that compound. Examples of matifying polymers that can be cited are silicone elastomers; resin particles; styrene acrylic copolymers (Ropaque OP 3000 sold by Rohm & Haas) and vinylpyrrolidone triacontene copolymers (Antaron WP 660 supplied by ISP) ; and mixtures thereof .

Examples of silicone elastomers that can be cited are the products sold under the trade names "KSG" by Shin-Etsu, "Trefil" , "BY29" or "EPSX" by Dow Corning or "Gransil" by Grant Industries.

Examples of resin particles that can be cited are melamine-formaldehyde and urea-formaldehyde resins described in EP-A-1 046 388. The term "tightening agent" means compounds that may have a tensing effect, i.e., which can tighten the skin and thereby smooth the skin and thus immediately reduce or even eliminate fine lines and wrinkles. Examples of tightening agents that can be cited are polymers of natural origin such as those described in in EP-A-0 912 165; synthetic polymers in the form of latex and pseudolatex such as those described in EP-A-0 944 381; dendritic polymers such as those described EP-A-0 987 016; "star" structured polymers such as those described in EP-A-1 043 345; mixed silicates; colloidal mineral dispersions; and mixtures thereof .

The polymer of the invention will be present in the cosmetic composition containing . it in an effective quantity for producing the desired effect. As an example, for application to the skin, the said polymer preferably represents 0.01% to 20%, more preferably 0.1% to 15% and still more preferably 0.5% to 5% of the total composition weight.

The composition of the invention can be fluid to a greater or lesser extent and have the appearance of a white or coloured cream, a pomade, a milk, a lotion, a serum, an aqueous transparent solution at 25°C, which may be gelled to a greater or lesser extent, a paste, or a foam. It can optionally be applied to the skin in the form of an aerosol or patch. It can also be in the solid form, in particular as a stick product for the lips or as a lipstick. It can be used as a skin care product and/or as skin or lip makeup . In a known manner, the composition of the invention can also contain adjuvants that are normal in the cosmetics field, such as hydrophilic or lipophilic gelling agents, hydrophilic or lipophilic active ingredients, preservatives, antioxidants, solvents, fragrances, filters, odour absorbers and colouring materials. The quantities of the said various adjuvants are those that are conventionally employed in the field under consideration, for example 0.01% to 20% of the total composition weight . Depending on their nature, the said adjuvants can be introduced into the oily phase or into the aqueous phase. In any event, the said adjuvants and the proportions thereof will be selected so that they do not deleteriously affect the desired properties of the polymer of the invention. The composition of the invention can be in the galenical forms normally used in the cosmetics field, and in particular in the form of an aqueous solution which may be gelled, an emulsion obtained by dispersion of an oily phase in an aqueous phase (O/W) or vice versa (W/0) , a triple emulsion (W/o/W or O/W/O) , an ionic (liposomes or oleosomes) and/or non- ionic (niosomes) type vesicular dispersion and/or a dispersion of nanocapsules or nanospheres.

For use in the cosmetic treatment of oily or combination skin, the composition of the invention will preferably be in the form of an O/W emulsion, the external aqueous phase of which provides a freshening effect.

When the composition of the invention is an emulsion, the proportion of the oily phase can be from 2% to 80% by weight, preferably 5% to 50% by weight with respect to the total composition weight . The oils, emulsifying agents and co-emulsifying agents used in the composition in the form of an emulsion are selected from those which are conventionally used in the field under consideration. The emulsifying agent . and co-emulsifying agent are generally present in the composition in a proportion of 0.3% to 30% by weight, preferably 0.5% to 20% by v/eight with respect to the total composition weight. In a variation, the composition of the invention in the form of an emulsion does not contain an emulsifying agent .

Examples of oils that can be used in the composition of the invention that can be cited are:

- hydrocarbon oils of animal origin, such as perhydrosqualene; - hydrocarbon oils of vegetable origin, such as liquid triglycerides of fatty acids containing 4 to 10 carbon atoms and the liquid fraction of karite butter;

- synthesized esters and. ethers, in particular of fatty acids, such as oils with formulae R¹COOR² and R^xOR² in which R¹ represents the residue of a fatty acid containing 8 to 29 carbon atoms, and R² represents a branched or unbranched hydrocarbon chain containing 3 to 30 carbon atoms, such as Purcellin oil, isononyl isononanoate, isopropyl myristate, 2-ethylhexyl palmitate, 2-octyldodecyl stearate, 2-octyldodecyl erucate, isostearyl isostearate; hydroxyl esters such as isostearyl lactate, octylhydroxystearate, octyldodecyl hydroxystearate, diisostearylmalate, triisocetyl citrate, fatty alcohol heptanoates, octanoates or decanoates; polyol esters such as propylene glycol dioctanoate, neopentylglycol diheptanoate or diethyleneglycol diisononanoate; and pentaerythritol esters such as pentaerythrityl tetraisostearate;

- linear or branched hydrocarbons of mineral or synthetic origin, such as paraffin oils, volatile or otherwise and their derivatives, petroleum jelly, polydecenes, hydrogenated polyisobutene such as parleam oil;

- fatty alcohols containing 8 to 26 carbon atoms, such as cetyl alcohol, stearyl alcohol and their mixtures (cetylstearyl alcohol) , octyldodecanol, 2-butyloctanol, 2-hexyldecanol, 2- undecylpentadecanol, oleic alcohol or linoleic alcohol;

- partially hydrocarbon-containing and/or silicone- containing fluorinated oils such as those described in Japanese patent JP-A-2-295912; - silicone oils such as polymethylsiloxanes (PDMS) , which may or may riot be volatile, containing a linear or cyclic silicone chain, which may be a liquid or paste at ambient temperature, in particular cyclopolydimethylsiloxanes (cyclomethicones) such as cyclohexasiloxane; polydimethylsiloxanes containing alkyl, alkoxy or phenyl -groups, which are pendent or at the end of the silicone chain, groups containing 2 to 24 carbon atoms; phenyl-containing silicones such as phenyltrimethicones, phenyldimethicones, phenyltrimethylsiloxydiphenylsiloxanes, diphenyldimethicones, diphenylmethyldiphenyltrisiloxanes, 2-phenylethyltrimethyl-siloxysilicates or polymethylphenylsiloxanes; - mixtures thereof.

Examples of other fats that may be present in the oily phase are fatty acids containing 8 to 30 carbon atoms such as stearic acid, lauric acid, palmitic acid or oleic acid; waxes such as lanolin, beeswax, carnauba wax or candelilla wax, paraffin waxes, lignite or microcrystalline waxes, ceresin or ozokerite, synthetic waxes such as polyethylene waxes, Fischer-Tropsch waxes; gums such as silicone gums (dimethiconol) ; silicone resins such as trifluoromethyl- (C1-C4) -alkyldimethicone or trifluoropropyldimethicone; and silicone elastomers such as products sold under the trade name "KSG" by Shin-Etsu, "Trefil", "BY29" or "EPSX" by Dow Corning or under the trade name "Gransil" by Grant Industries. The said fats can be selected by the skilled person in order to prepare a composition having the desired, properties, _£or_example as regards consistency or textux'e.

The emulsifying surfactants are selected as appropriate depending on the emulsion to be obtained (W/O or O/W) .

For O/W emulsions, for example, it is possible to use as the emulsifying surfactant a non- ionic emulsifying surfactant, containing ose esters or ethers such as sucrose stearate, sucrose cocoate, and a mixture of sorbitan stearate and sucrose cocoate sold by ICI under the trade name Arlatone 2121^®; polyol esters, in particular glycerol or sorbitol, such as glyceryl stearate, polyglyceryl-2 stearate or sorbitan stearate; glycerol ethers; oxyethylenated and/or oxypropylenated ethers such as the oxyethylenated; oxypropylenated ether of lauryl alcohol containing 25 oxyethylenated groups and 25 oxypropylenated groups (CTFA name "PPG-25 laureth-25") and the oxyethylenated ether of a mixture of C12-C15 fatty alcohols containing 7 oxyethylenated groups (CTFA name "C12-C15 Pareth-7"); ethylene glycol polymers such as PEG-100, and their mixtures .

Examples of emulsifying surfactants for W/O emulsions are polyol fatty esters, in particular of glycerol or sorbitol, in particular isostearic, oleic and ricinoleic polyol esters, such as the mixture of petrolatum, . olyglyceryl-3 oleate, glyceryl isostearate, hydrogenated castor oil and ozokerite sold by Goldschmidt under the trade name PROTEGIN vf , sorbitan isostearate, polyglyceryl di-isostearate, polyglyceryl-2 sesqui-isostearate; esters and ethers of oses such as "methyl glucose dioleate" ; fatty esters such as magnesium lanolate; dimethicone copolyols and alkyl-dimethicone copolyols such as laurylmethicone copolyol sold by Dow Corning under the trade name DOW CORNING 5200 FORMULATION AID and cetyl dimethicone copolyol sold by Goldschmidt under the trade name ABIL EM 90 , and mixtures thereof.

The emulsifying surfactants can be introduced as is or in the form of a mixture with other emulsifying surfactants and/or with other compounds such as fatty alcohols or oils.

It is. also possible to use, as emulsifying agents, amphiphilic polymers such as modified acrylic copolymers, for example products sold by Goodrich under the trade name Pemulen; 2-acrylamido-2-methylpropane sulphonic acid copolymers with a hydrophobic chain such as those described in EP-A-1 069 142; polyolefins with a succinic termination, optionally esterified or amidified, such as the compounds described in US-A-4,234,435, US-A-4 , 708, 753 , US-A-5, 129, 972 ,

US-A-4,931,110, GB-A-2 , 156 799 and US-A-4 , 919 , 179. Examples of _polyolefins with a succinic termination that can be cited are polyisobutylenes with a modified succinic termination, such as the products sold by Lubrizol under the trade name_L2724 and L2721. The quantity of emulsifying surfactant can be from 0 to 1% in emulsions that are free of emulsifying surfactant. In other emulsions, the quantity of emulsifying agents (surfactant or polymer) can be from 0.01% to 10% of the total composition weight. Examples of hydrophilic gelling agents that can in particular be cited are carboxyvinyl polymers (carbomers) , acrylic copolymers such as acrylate/alkylacrylate copolymers (Pemulen) , polyacrylamides, in particular those derived from acrylamido-2-methyl propane sulphonic acid (Hostacerin AMPS supplied by Clariant, and Sepigel 305 supplied by Seppic) , polysaccharides such as cellulose derivatives, natural gums and clays and, as lipophilic gelling agents, modified clays such as bentonites, metal salts of fatty acids, hydrophobic silica and polyethylenes.

For use in the cosmetic treatment for oily or combination skin, the composition of the invention will preferably contain at least one active ingredient selected from: vitamins B3 and B5; zinc salts, in particular zinc oxide or zinc gluconate; salicylic acid and its derivatives such as n-octanoyl-5-salicylic acid; antibacterial active ingredients such as 2,4,4'- trichloro-2' -hydroxydiphenylether (triclosan) ; capryloylglycine; oil of cloves; octopirox; hexamidine; and azelaic acid and its derivatives . The composition may also contain the following active ingredients : moisturizing agents, for example hydrolystates of proteins and polyols such as glycerin, glycols such as polyethylene glycols, and sugar derivatives; natural extracts; antiinflammatories; procyanidolic oligomers; vitamins such as vitamin A (retinol) , vitamin C

(ascorbic acid) , vitamin E (tocopherol) , derivatives of the said vitamins (esters in particular) and mixtures thereof; urea; caffeine; depigmenting agents such as kojic acid , hydroquinone or caffeic acid; salicylic acid and its derivatives; alpha-hydroxyacids such as lactic acid and glycolic acid and their derivatives; ■retinoids such as carotenoids and vitamin A derivatives; hydrocortisone; melatonin; extracts from algae, fungi, plants, yeasts or bacteria; enzymes; DHEA and its derivatives and metabolites; 3,4,4'- trichlorocarbanilide (or triclocarban) and the acids indicated above; and mixtures thereof.

In the event of incompatibility or to stabilize them, at least some of the active ingredients mentioned above can be incorporated into spherules, in particular ionic or non-ionic vesicles and/or nanoparticles (nanocapsules and/or nanospheres) .

Sunscreens can be selected from chemical filters, physical filters and mixtures thereof. Examples of sunscreens that can be cited are:

- butylmethoxydibenzoylmethane sold by Hoffmann- Laroche under the trade name Parsol 1789;

- octocrylene sold by BASF under the trade name Uvinul N539; - octylsalicylate sold by Haarman-Reimer under the trade name Neo Heliopan OS;

- octylmethoxycinnamate sold by Hoffmann-Laroche under the trade name Parsol MCX;

- phenylbenzimidazole sulphonic acid sold by Merck under the trade name Eusolex 232;

- oxybenzones such as benzophenone-3 , -4 or -5;

- benzotriazole silicones, in particular drometrizole trisiloxane;

- terephthalylidene di-camphor sulphonic acid, in particular Mexoryl SX sold by Chimex;

- benzotriazole silicones, in particular those described in French application FR-A-2 642 968;

- as well as insoluble organic filters such as triazine derivatives, in particular 2, 4-bis { [4- (2-ethyl-hexyloxy) -2-hydroxy] phenyl} -6- (4-methoxy- phenyl) -1, 3, 5-triazine available from CIBA GEIGY under the trade name TINOSORB S, and 2,2'- methylene-bis- [6- (2H-benzotriazol-2-yl) -4- (1, 1, 3, 3-tetramethylbutyl)phenol] available from CIBA GEIGY under the trade name TINOSORB M. Examples of physical sunscreens that can be cited are titanium or zinc oxides, in the form of micro- or nanoparticles (nanopigments) which may be coated, and mixtures thereof. An example that can be cited is the hydrophilic nanotitanium sold by Rhodia under the trade name MIRASUN TIW60, and the lipophilic nanotitanium sold by TAYCA under the trade name MTIOOT.

The invention will be better understood ^■and its advantages will be made clearer in the following examples which are given by way of non-limiting illustration.

Example 1; Matifying creasa

Aqueous phase

Sodium polyacrylate, 450 000 g/mol, carrying grafts of Jeffamine M-2005 (random copolymer of ethylene oxide (6) and propylene oxide (39)); degree of grafting = 3.9 mol %* 4.22 g

Glycerin 5 g

Preservatives 0.5 g

EDTA 0.05 g

Demineralized water 74.58 g

Oily phase

Stearyl alcohol 1 g

Mixture of dimyristyl tartrate / cetearyl alcohol/ C₁₂-C₁5 Pareth-7/PPG-25 Laureth-25 (Cosmacol PSE from Enichem) 1.5 g

Mixture of glyceryl stearate and PEG-100 stearate (Arlacel 165 from ICI) 2 g

Cyclohexadimethylsiloxane 11 g

Preservative 0.15 g

* The demixing temperature at 1% in water for the Jeffamine M-2005 LCST units is 25°C. The gelling temperature at 2% by weight in water for this polymer is 28°C.

The aqueous phase was prepared by dissolving the polymer of the invention in demineralized water containing the preservative, EDTA and glycerin, with stirring for 2 hours. The oily phase, previously heated to 75°C, was then slowly introduced into the aqueous phase, also heated to 75°C, with stirring, using a Moritz type mixer running at a speed of 4000 rpm for 20 minutes .

-Ssεsι ple_2 :_ D.<ssaoasts:atioa of optical _^properties

Protocol :

The following four compositions A to D were tested:

- composition A corresponded to that of Example 1;

- composition B was identical to that of Example 1, except that the polymer in the aqueous phase had a degree of grafting of 2 mol% (the gelling temperature at 2% by weight in water for this polymer was 33°C) ;

- composition C was identical to that of Example 1, except that the polymer in the aqueous phase was replaced with an equal quantity of silica microbeads (Silica .Beads SB 150 from MIYOSHI) ; and

- composition D was identical to that of Example 1, except that it did not have any polymer in the aqueous phase, the quantity of water being increased as a consequence. The principle of the method consisted of measuring, using a goniore lectometer, the specular reflection and the diffuse reflection of a deposit of each composition to be evaluated, spread beforehand at the temperature T on a rubber support in an amount of 2 mg/cm². The deposits were then dried at temperature T for 30 minutes. The spreading and drying phases were carried out at two temperatures: 20°C and 37°C to demonstrate the influence of temperature on the optical properties of the compositions .

The optical effect was then evaluated from the ratio R of the specular reflections (measured at an angle of 30°) and the diffuse reflections (measured at an angle of 0°) .

An optical effect sufficient to modify the appearance of the skin and render the complexion matte and homogeneous was obtained when this ratio R was at most 1.9 and preferably less than 1.6, while a ratio R of more than 2, and especially more than 2.2, was considered to mean an absence of improvement of the appearance of the skin. Results :

The results obtained for the four test compositions are shown in the table below:

The table clearly shows that only compositions A and B in accordance with the invention can homogenize the appearance of the skin, in particular camouflage pores and blemishes and mat fy the complexion. These properties of the compositions of the invention are maintained (composition B) or even enhanced (composition A) as the temperature is raised, corresponding to passage from the packaging temperature to the skin temperature .

Further, the gelling power of composition A was 1200

Pa.s at 20°C (0.1 s^"1) and 3000 Pa.s at 32°C (0.1 s^"1) , and that of composition B was 1000 Pa.s at 20°C

(0.1 s^"1) and 2500 Pa.s at 32°C (0.1 s^"1) . These compositions are thus both relatively fluid to the touch and thicker on application to the skin, which renders application easy and agreeable.

Claims

1. Cosmetic use, in a composition comprising a physiologically acceptable medium, as an agent for matifying the skin and/or for concealing blemishes and/or for camouflaging pores, of at least' one hydrosoluble or hydrodispersible polymer comprising hydrosoluble or hydrodispersible units and LCST units, the said LCST units having, in water, a demixing temperature (or cloud point) of 5°C to 40°C at a concentration by weight of 1%, the said composition being free of any other compound having an optical effect selected from fillers, nacres, pigments, matifying polymers and tightening agents.

2. Use, in the cosmetic treatment for greasy or combination skin, of a composition containing, in a physiologically acceptable medium, at least one hydrosoluble or hydrodispersible polymer comprising hydrosoluble or hydrodispersible units and LCST units, the said LCST units having, in water, a demixing temperature (or cloud point) of 5°C to 40°C at a concentration of 1% by weight, the said composition being free of any other compound having an optical effect selected from fillers, nacres, pigments, matifying polymers and tightening agents .

3. Use according to Claim 2, characterized in that the said composition is in the form of an oil- in-water emulsion.

4. Use according to Claim 2, characterized in that the composition further comprises at least one active ingredient selected from: vitamins B3 and B5; zinc salts, in particular zinc oxide and zinc gluconate; salicylic acid and its derivatives such as n-octanoyl-5-salicylic acid; triclosan; capryloylglycine; oil of cloves; octopirox; hexamidine; and azelaic acid and its derivatives .

5. Use according to any one of Claims 1 to

4, in which the polymer has a gelling temperature of 5°C to 50°C for a concentration of 2% by weight in water .

6. Use according to any one of Claims 1 to 5, in which the polymer is in the form of a block polymer comprising alternating hydrosoluble or hydrodispersible units and LCST units or in the form of a graft polymer comprising a backbone, which is optionally cross-linked, formed from hydrosoluble or hydrodispersible units and carrying grafts constituted by LCST units or vice versa.

7. Use according to any one of Claims 1 to 6, in which all or a portion of the hydrosoluble or hydrodispersible units of the polymer are/is obtained by polymerization of at least one hydrosoluble monomer or its salt selected from: - (meth) acrylic acid;

- vinylsulphonic acid;

- (meth) allylsulphonic acid;

- vinylphosphonic acid; - methyl vinylimidazolium chloride;

- (meth) acrylamide;

- 2-vinylpyridine, 4-vinylpyridine;

- maleic acid and maleic anhydride;

- crotonic acid; - itaconic acid;

- vinyl alcohol;

- N-vinyllactams comprising a cyclic alkyl group containing 4 to 9 carbon atoms, such as N- vinylpyrrolidone, N-vinylcaprolactam and N-butyrolactam;

- hydrosoluble styrene derivatives, in particular styrene sulphonate;

- dimethyldiallyl ammonium chloride;

- N-vinylacetamide and N-methyl,N-vinylacetamide; - N-vinylformamide and N-methyl N-vinylformamide;

- vinyl monomers with formula (I) below:

H₂C=CR _(|)

C i O

X in which : - R is selected from H, -CH₃ , -C₂H₅ or -C₃H₇, and - X is selected from:

- alkyl -OR' type oxides, in which R' is a saturated or unsaturated, linear or branched hydrocarbon radical containing 1 to 6 carbon atoms, substituted with at least one group selected from halogen atoms (iodine, bromine, chlorine, fluorine) ; sulphonic (-S0₃ ^~) , sulphate (-S0₄ ^") , phosphate (-P0₄H₂ ^") ; hydroxyl (-OH) ; ether (-0-) ; primary amine (-NH₂) ; secondary amine (-NHRi), tertiary amine (-NR_XR₂) or quaternary amine (-N⁺RιR₂R₃) groups in which R_lf R₂ and R₃ independently represent a saturated or unsaturated, linear or branched hydrocarbon radical containing 1 to 6 carbon atoms, provided that the sum of the carbon atoms of R' + R_x +. R₂ + R₃ does not exceed 7; and

- NH₂, -NHR₄ and -NR₄R₅ groups in which R and R₅ independently represent saturated or unsaturated, linear or branched hydrocarbon radicals containing 1 to 6 carbon atoms, provided that the total number of carbon atoms of R₄ + R₅ does not exceed 7, the said R and R₅ being substituted with at least one group selected from halogen atoms (iodine, bromine, chlorine, fluorine) ; hydroxyl (-OH) ; sulphonic (-SO₃ ^") ; sulphate (-S0₄ ^~) ; phosphate (-P0₄H₂ ^") ; primary amine (-MH₂) ; secondary amine (-NHRi) , tertiary amine (-NR1R2) and/or quaternary amine (-N⁺RχR₂R₃) groups in which R_if R₂ and R₃, independently represent a saturated or unsaturated, linear or branched hydrocarbon radical containing 1 to 6 carbon atoms, provided that the sum of the carbon atoms of R₄ + R₅ + R_x + R₂ + R₃ does not exceed 7.

8. Use according to any one of Claims 1 to 6, in which all or a portion of the hydrosoluble or hydrodispersible units of the polymer are/is obtained by copolymerization of at least one hydrophobic monomer with at least one hydrosoluble monomer, the said hydrophobic monomer being in a quantity such that the resulting units are hydrosoluble or hydrodispersible, the said hydrophobic monomer being selected from:

- styrene and its derivatives such as 4- butylstyrene, alpha-methylstyrene or vinyltoluene; - vinyl acetate with formula CH₂=CH-OCOCH_3;

- caprolactone; vinyl chloride and vinylidene chloride; silicone derivatives such as methacryloxypropyltris (trimethylsiloxy) silane and silicone methacrylamides, hydrophobic vinyl monomers with formula (II) below:

H₂C CR

CO (II)

Xi in which:

- R₇ is selected from H, -CH₃, -C₂H₅ or C₃H₇, - Xi is selected from:

- groups NH₂, -NHR₉ and -NR₉Rι₀ in which R₉ and R_i0 independently form saturated or unsaturated, linear or branched hydrocarbon radicals containing 1 to 22 carbon atoms, provided that the total number of carbon atoms of R₉ + _ι0 does not exceed 23.

9. Use according to Claim 7 or Claim 8, in which the hydrosoluble or hydrodispersible units of the polymer are completely or partially neutralized by a mineral or organic base selected from sodium, ammonium, lithium, calcium, magnesium salts, ammonium salts substituted with 1 to 4 alkyl groups containing 1 to 15 carbon atoms, mono-, di- or tri-ethanolamine, aminoethylpropanediol, N-methylglucamine, basic amino acids such as arginine or lysine, and mixtures thereof.

10. Use according to any one of Claims 7 to 9, in which the hydrosoluble or hydrodispersible units of the polymer are cross-linked by the action of at least one compound selected from divinylbenzene, diallyl ether, dipropyleneglycol-diallylether, polyglycol-diallylethers, triethyleneglycol- divinylether, hydroquinone-diallyl-ether, tetrallyl- oxethanoyl, allyl or vinylether derivatives of polyfunctional alcohols, t traethyleneglycol diacrylate, triallylamine, trimethylolpropanediallylether, tetraallyloxyethane, methylene-bis-acrylamide, allyl ethers of sugar series alcohols, allyl methacrylate, trimethylol propane triacrylate (TMPTA) and mixtures thereof.

11- Use according to any one of Claims 1 to

6, in which all or a portion of the hydrosoluble or hydrodispersible units of the polymer are/is constituted by one or more of the following components:

- hydrosoluble polyurethanes, - xanthan gum;

- alginates and their derivatives such as propyleneglycol alginate,

- cellulose derivatives, in particular carboxymethylcellulose, hydroxypropylcellulose, hydroxyethylcellulose and quaternized hydroxyethylcellulose,

- galactomannanes and their derivatives such as Konjac gum, guar gum, hydroxypropylguar, hydroxypropylguar modified by sodium methylcarboxylate groups and guar hydroxypropyl trimethyl ammonium chloride, and

- polyethylene-imine.

12. Use according to any one of Claims 1 to

11, in which the hydrosoluble or hydrodispersible units have a molar mass of 1000 g/mol to 10 000 000 g/mol when they constitute the hydrosoluble backbone of a graft polymer, or a molar mass of 500 g/mol to 500 000 g/mol when they constitute a block of a multiblock polymer or when they constitute the grafts of a graft polymer .

13. Use according to any one of Claims 1 to

12, in which the LCST units are constituted by one or more of the following polymers :

- polyvinylmethylether, - polymeric and copolymeric N-substituted derivatives of acrylamide having an LCST, and

- poly-N-vinylcaprolactam and N-vinylcaprolactam copolymers .

14. Use according to Claim 13 , in which the

LCST units are constituted by random copolymers of ethylene oxide (OE) and propylene oxide (OP) represented by the formula:

(OE)_m(OP)_n in which m is a whole number from 1 to 40, preferably 2 to 20, and n is a whole number from 10 to 60, preferably 20 to 50.

15.- Use according to Claim 14, in which the molar mass of the said LCST units is 500 to 5300 g/mol, preferably 1500 to 4000 g/mol.

16. Use according to Claim 13 , in which the LCST units are polymeric or copolymeric N-substituted acrylamide derivatives having an LCST, such as poly-N- isopropyl acrylamide, poly-N-ethyl acrylamide and copolymers of N-isopropyl acrylamide or N-ethyl acrylamide and a vinyl monomer with formula (I) or (II) as defined in Claim 7 or Claim 8, or a monomer selected from (meth) acrylic acid, vinylsulphonic acid, (meth) allylsulphonic acid, maleic acid and maleic anhydride, vinylphosphonic acid, crotonic acid, itaconic acid, (meth) acrylamide, vinylpyridine, vinyl alcohol, N-vinyllactams such as N-vinylpyrrolidone, styrene and its derivatives, dimethyldiallyl ammonium chloride, N-vinylacetamide, N-methyl, N-vinylacetamide, N-vinylformamide, N-methylvinylformamide, vinylethers and vinyl acetate derivatives, acrylonitrile, caprolactone, vinyl chloride and vinylidene chloride.

17. Use according to Claim 16, in which the said derivatives have a molar mass of 1000 g/mol to 500 000 g/mol.

18. Use according to Claim 13, in which the

LCST units are constituted by a poly-N-vinylcaprolactam or a copolymer of N-vinylcaprolactam and a vinyl monomer with formula (I) or (II) as defined in Claim 7 or Claim 8, or a monomer selected from (meth) acrylic acid, vinylsulphonic acid, (meth) allylsulphonic acid, maleic acid, maleic anhydride, vinylphosphonic acid, crotonic acid, itaconic acid, (meth) acrylamide, vinylpyridine, vinyl alcohol, N-vinyllactarns such as N- vinylpyrrolidone, styrene and its derivatives, dimethyldiallylammonium chloride, N-vinylacetamide, N- methyl-N-vinylacetamide, N-vinylformamide, N- methylvinylformamide, vinyl acetate, vinylethers, acrylonitrile, caprolactone, vinyl chloride and vinylidene chloride.

19. Use according to Claim 18, in which the molar mass of the LCST units is 1000 g/mol to 500 000 g/mol .

20. Use according to any one of Claims 1 to

19, in which the proportion by weight of LCST units in the polymer is 5% to 70%, preferably 20% to 65%, and more preferably 30% to 60% with respect to the polymer.

21. Use according to any one of Claims 1 to

20, in which the demixing temperature of the LCST units is 10°C to 35°C for a concentration by weight of LCST units in water of 1% .

22. Use according to any one of Claims 1 to

21, in which the polymer represents 0.01% to 20%, preferably 0.1% to 15% of the total composition weight.

23. Use according to any one of the preceding claims, characterized in that the said composition is a transparent aqueous solution at 25°C.