FR2842415A1 - Use of composition comprising hydrosoluble and/or hydro-dispersible polymer comprising HS or HD units and LCST units in medium, for matifying, concealing blemishes and/or for camouflaging pores of skin - Google Patents

Abstract

The composition comprising hydrosoluble and/or hydro-dispersible (HS and/or HD) polymer comprising HS or HD units and LCST (low critical solution temperature) units in a medium, is used as an agent for matifying skin, concealing blemishes and/or for camouflaging pores. The LCST units have a de-mixing temperature (or cloud point) of 5-40 [deg]C at 1 wt.% in water. The composition is free of compounds having an optical effect. The composition comprising hydrosoluble and/or hydro-dispersible (HS and/or HD) polymer comprising HS and/or HD units and LCST units in a medium, is used as an agent for matifying the skin and/or for concealing blemishes and/or for camouflaging pores. The LCST units have a de-mixing temperature (or cloud point) of 5-40 [deg]C at a concentration of 1 wt.% in water. The composition is free of compounds having an optical effect selected from fillers, nacres, pigments, matifying polymers and tightening agents.

Description

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The invention relates to the cosmetic use, in a composition comprising a physiologically acceptable medium, as an agent for mattifying the skin and / or for concealing the rings and / or for concealing the pores, of at least one polymer water-soluble or water-dispersible composition comprising LCST units, said composition being free from any other optically active compound.

The subject of the invention is also the use, in the cosmetic treatment of oily or combination skin, of a composition containing, in a physiologically acceptable medium, the abovementioned polymer, to the exclusion of any other compound with an optical effect. the skin, often associated with a high secretion of sebum, and its inhomogeneity due to superficial defects such as wrinkles, dilated pores or color variations such as dark circles are problems faced by women of all ages. The inhomogeneity of the complexion may also be due to the poor performance of makeup, the appearance of which tends to deteriorate during the day.

The means used up to now to reduce the gloss of the skin have essentially consisted in using fillers such as talc, starch, mica, silica, nylon powders, polyethylene powders, poly powders. -beta-alanine and powders of poly [methyl (meth) acrylate]. These fillers, however, have the disadvantage of giving the skin an unnatural powdery appearance that can even accentuate its defects. In addition, these compositions generally cause drying of the skin in the long term. Their matte effect is also short-lived.

In addition, these mattifying compositions require the use of gelling agents to obtain textures that are easy to apply and pleasant to the touch. However, conventional cosmetic gelling agents which consist of acrylic polymers, xanthan gum or starch have their viscosity decrease by raising the temperature. Thus, any fluid composition at 20 C remains fluid at skin temperature (32 C), which does not lead to good application properties. On the other hand, gel compositions at skin temperature, easier to apply, must also be gelled at 20 C; the range of accessible textures for the mattifying compositions is therefore limited.

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 It thus appears necessary to identify compounds allowing to modify the appearance of the skin by optical effect that are non-drying and non-irritating vis-à-vis the skin and allow to expand the range of galenic media and accessible textures for the compositions containing them.

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

These thermogelling polymers are water-soluble or water-dispersible polymers which comprise water-soluble or water-dispersible units and units with LCST. Such polymers have already been described in the following documents: D. Hourdet et al., Polymer, 1994, vol. 35, No. 12, pp. 2624-2630; ALLORET et al., Coll. Polym. Sci., 1995, vol.

273, No. 12, pp. 1163-1173; F. ALLORET et al., Journal of the French Institute of Petroleum, 1997, vol. 52, No. 2, pages 117-128; EP-A-0 583 814 and EP-A-0 629 649.

pouvoir collant superficiel d' ul1Jilm1)u~dépôLabterllLà-partiLd'une-composition-à-effet-Qptque-::-:: contenant ledit polymère et un autre agent à effet optique choisi parmi les charges, les nacres, les pigments, les polymères matifiants et les agents tenseurs (FR-2 819 397, non publié). La Demanderesse a par ailleurs mis en évidence leur capacité à lisser les rides et ridules cutanés par effet tenseur. These polymers have already been described as being useful for ensuring the stability of cosmetic dispersions when subjected to temperature variations in the range of 4 to 50 ° C. (FR-2,819,415, unpublished). They are also known to cancel or reduce the

superficial stickiness of poly (1) -subject-deposition-of-a-composition-to-effect-:: - :: containing said polymer and another optical effect agent selected from fillers, nacres, pigments, mattifying polymers and tensors (FR-2,819,397, unpublished). The Applicant has also demonstrated their ability to smooth wrinkles and fine lines skin tightening effect.

However, to the knowledge of the Applicant, it has never been suggested to use the thermogelling polymers of the prior art without other optical effect agent, to change the appearance of the skin and in particular to matify . This matting property imparted by the polymers used according to the invention is particularly surprising in view of the tendency of the majority of water-soluble polymers to form, on the contrary, glossy deposits on the skin.

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The subject of the present invention is therefore the cosmetic use, in a composition comprising a physiologically acceptable medium, as an agent for mattifying the skin and / or for blurring the rings and / or for concealing the pores, of at least one water-soluble or water-dispersible polymer comprising water-soluble or water-dispersible units and units with an LCST, said units with LCST having in water a demixing temperature (or cloud point) of 5 to 40 C at a mass concentration of 1%, said composition being free from any other optical effect compound chosen from fillers, nacres, pigments, mattifying polymers and tensing agents.

The subject of the invention is also the use, in the cosmetic treatment of oily or combination skin, of a composition containing, in a physiologically acceptable medium, at least one water-soluble or water-dispersible polymer comprising water-soluble or water-dispersible units and water-soluble units. LCST, said LCST units having in water a demixing temperature (or cloud point) of 5 to 40 C at a mass concentration of 1%, said composition being free of any other optically selected compound selected from fillers, nacres, pigments, mattifying polymers and tensors.

 One of the major advantages of the polymers according to the invention is that their optical properties are conserved, or even enhanced (as indicated in Example 2 below) during a rise in temperature, unlike conventional mattifying agents which lose their efficiency due to sweating, in particular. This advantage makes the compositions containing them well suited for use in hot climates.

 According to the invention, polymers having a gelling temperature of 5 to 50 ° C., preferably 15 to 40 ° C., are preferably used for a mass concentration in water of 2%. This feature is particularly interesting because it provides access to a wide range of textures in cosmetic compositions. These polymers have, as mentioned above, gelling properties in the aqueous phase stimulated by a rise in temperature. Thus, thanks to the polymers according to the invention, it is possible to access cosmetic compositions having a wide range of textures, which is not the case for the compositions of the prior art which require, in addition to mattifying agents, astringents or anti-radiation agents. - classic rings, the addition of gelling agents.

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 The polymers used in the context of the invention may be in the form of block polymers (or blocks) comprising water-soluble or water-dispersible units and alternating LCST units, or in the form of graft polymers consisting of an optionally crosslinked backbone formed of water-soluble or hydrodispersible units and carrying grafts consisting of units with LCST or vice versa.

The water-soluble or water-dispersible units of these polymers are preferably water-soluble units, from 5 to 80 C, in a proportion of at least 10 g / l, preferably at least 20 g / l.

However, it is also possible to use as units that are water-soluble or water-dispersible units which do not necessarily have the solubility mentioned above, but which in aqueous solution at 1% by weight, from 5 ° C. to 80 ° C., make it possible to obtain a solution macroscopically homogeneous and transparent, ie having a maximum transmittance value of light, regardless of the wavelength between 400 and 800 nm, through a sample of 1 cm thick, at least 85%, preferably at least 90%.

polycondensatio---o--ersare--pe ,ri+e-G#Et'tes; -dolymères=rtatuels= naturels modifiés existants. These water-soluble or water-dispersible units do not have a temperature of demixing by heating of the LCST type. These water-soluble or water-dispersible units can be obtained by radical polymerization of vinyl monomers, or by

polycondensatio --- o - ersare - pe, ri + eG # Et'tes; -dolymers = existing = existing modified natural.

By way of examples, mention may be made of the following water-soluble monomers and their salts, which may be used to form, in whole or in part, by polymerization, said water-soluble or water-dispersible units, alone or as a mixture: (meth) acrylic; vinylsulfonic acid; - (meth) allylsulfonic acid; vinylphosphonic acid; methyl vinylimidazolium chloride; (meth) acrylamide; 2-vinylpyridine, 4-vinylpyridine; maleic acid and anhydride;

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dans laquelle : - R est choisi parmi H, -CH3, -C2H5 ou -C3H7, et - X est choisi parmi : - les oxydes d'alkyle de type-OR', où R' est un radical hydrocarboné, linéaire ou ramifié, saturé ou insaturé, ayant 1 à 6 atomes de carbone, substitué par au moins un groupe choisi parmi les atomes d'halogène (iode, brome, chlore, fluor); les groupements sulfonique (-SO3-), sulfate (-SO4), phosphate (-PO4H2-) ; hydroxy (-OH) ; éther (-O) ; amine primaire (-NH2), amine secondaire (-NHRi), amine tertiaire (-NR1R2) ou quaternaire (-N+R1R2R3) avec R1, R2 et R3 étant, indépendamment l'un de l'autre, un radical hydrocarboné, linéaire ou ramifié, saturé ou insaturé ayant 1 à 6 atomes de carbone, sous réserve que la somme des atomes de carbone de R' + R1 + R2 + R3 ne dépasse pas 7 ; et-les groupements -NH2, -NHR4 et -NR4R5 dans lesquels R4 et R5 sont indépendamment l'un de l'autre des radicaux hydrocarbonés, linéaires ou ramifiés, saturés ou insaturés ayant 1 à 6 atomes de carbone, sous réserve que le nombre total d'atomes de carbone de R4 + R5 ne dépasse pas 7, lesdits R4 et R5 étant substitués par au moins un groupe choisi parmi les atomes d'halogène (iode, brome, chlore, fluor) ; les groupements hydroxy (-OH) ; éther (-0-) ; sulfonique (-SO3-) ; sulfate (-SO4-) ; phosphate (-PO4H2-) ; amine primaire (-NH2) ; amine secondaire (-NHR,), tertiaire (-NR1R2) et/ou quaternaire (-N+R1R2R3) avec R1, R2 et R3 étant, indépendamment l'un de l'autre, un radical hydrocarboné, linéaire ou ramifié, saturé ou crotonic acid; - itaconic acid; the vinyl alcohol of formula CH 2 = CHOH; N-vinyllactams having a cyclic alkyl group of 4 to 9 carbon atoms such as N-vinylpyrrolidone, N-vinylcaprolactam and N-butyrolactam; water-soluble derivatives of styrene, in particular styrene sulphonate; dimethyldiallyl ammonium chloride; N-vinylacetamide and N-methyl, N-vinylacetamide; N-vinylformamide and N-methyl-N-vinylformamide; the vinyl monomers of formula (I) below:

in which: - R is chosen from H, -CH3, -C2H5 or -C3H7, and - X is chosen from: - the type-OR 'alkyl oxides, where R' is a linear or branched hydrocarbon radical, saturated or unsaturated, having 1 to 6 carbon atoms, substituted by at least one group selected from halogen atoms (iodine, bromine, chlorine, fluorine); sulfonic groups (-SO3-), sulfate (-SO4), phosphate (-PO4H2-); hydroxy (-OH); ether (-O); primary amine (-NH2), secondary amine (-NHRi), tertiary amine (-NR1R2) or quaternary amine (-N + R1R2R3) with R1, R2 and R3 being, independently of one another, a linear hydrocarbon radical or branched, saturated or unsaturated having 1 to 6 carbon atoms, provided that the sum of the carbon atoms of R '+ R1 + R2 + R3 does not exceed 7; and the groups -NH2, -NHR4 and -NR4R5 in which R4 and R5 are independently of each other linear or branched, saturated or unsaturated hydrocarbon radicals having 1 to 6 carbon atoms, provided that the number total of carbon atoms of R4 + R5 does not exceed 7, said R4 and R5 being substituted by at least one group selected from halogen atoms (iodine, bromine, chlorine, fluorine); hydroxy groups (-OH); ether (-O-); sulfonic (-SO3-); sulfate (-SO4-); phosphate (-PO4H2-); primary amine (-NH2); secondary amine (-NHR 2), tertiary (-NR 1 R 2) and / or quaternary (-N + R 1 R 2 R 3) with R 1, R 2 and R 3 being, independently of one another, a hydrocarbon radical, linear or branched, saturated or

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 unsaturated having 1 to 6 carbon atoms, with the proviso that the sum of the carbon atoms of R4 + R5 + R1 + R2 + R3 does not exceed 7.

 As examples of water-soluble monomers of formula (1), mention may be made of glycidyl (meth) acrylate, hydroxyethyl methacrylate, ethylene glycol, diethylene glycol or polyalkylene glycol (meth) acrylates, N, N-dimethylacrylamide, acrylamido-2-methylpropanesulphonic acid (AMPS), (meth) acrylamido propyltrimethylammonium chloride (APTAC and MAPTAC) and dimethylaminoethylquaternized methacrylate (MADAME).

dans laquelle : - ?7 est choisi parmi H, -CH3, -C2H5 ou C3H7, Mention may also be made, also among the monomers that may be used to form, in all or part, by polymerization, the water-soluble or water-dispersible units, hydrophobic monomers, said monomers being copolymerized with at least one water-soluble monomer in an amount such that the the resulting units are water-soluble or water-dispersible, said hydrophobic monomers being selected from the following monomers: styrene and its derivatives such as 4-butylstyrene, alpha-methylstyrene and vinyltoluene; vinyl acetate of formula CH2 = CH-OCOCH3; vinyl ethers of formula CH2 = CHOR6, in which R6 is a hydrocarbon-linear-or-branched-saturated or unsaturated radical having 1 to 6 carbon atoms; acrylonitrile; caprolactone; vinyl chloride and vinylidene chloride; silicone derivatives such as methacryloxypropyltris (trimethylsiloxy) silane and silicone methacrylamides, the hydrophobic vinyl monomers of formula (II) below:

wherein: - 7 is selected from H, -CH3, -C2H5 or C3H7,

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 - X1 is chosen from: - alkyl oxides of the type -OR8 where R8 is a hydrocarbon radical, linear or branched, saturated or unsaturated, having 1 to 22 carbon atoms; the groups NH 2, -NHR 9 and -NR 9 R 10 in which R 8 and R 10 are, independently of each other, linear or branched, saturated or unsaturated hydrocarbon radicals having 1 to 22 carbon atoms, provided that the total number of carbon atoms of Rg + Rio does not exceed 23.

By way of examples of such monomers, mention may be made of methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, cyclohexyl acrylate, isobornyl acrylate and the like. ethyl acrylate-2-hexyl.

The water-soluble or water-dispersible units may be neutralized, where appropriate, in whole or in part, with an inorganic or organic base chosen from sodium, ammonium, lithium, calcium, magnesium or ammonium salts substituted with 1 to 4 alkyl groups carrying 1 at 15 carbon atoms, or among mono-, di- and triethanolamine, aminoethylpropanediol, N-methylglucamine, basic amino acids such as arginine and lysine, and mixtures thereof.

-aetiol1-d-'-1 J---rY)oin$IIn--aget1t:-::derétic' datiQll=cboisi-parmHes-comtiull oléfinique couramment utilisés pour la réticulation des polymères obtenus par polymérisation radicalaire. A titre d'exemple de tels agents, on peut citer le divinylbenzène, l'éther diallylique, le dipropylèneglycol-diallyléther, les polyglycol-diallyléthers, le triéthylèneglycol-divinyléther, l'hydroquinone-diallyl-éther, le tétrallyl-oxéthanoyle, les dérivés allyl-ou vinyléthers alcools polyfonctionnels, le diacrylate de tétraéthylèneglycol, la triallylamine, le triméthylolpropanediallyléther, le tétraallyloxyéthane, le méthylène-bis-acrylamide, les éthers allyliques d'alcools de la série des sucres, le méthacrylate d'allyle, le triméthylol propane triacrylate (TMPTA) et leurs mélanges. De préférence, on utilise un squelette de polymère greffé non réticulé. It can also be noted that the backbone of the graft polymers can be crosslinked by

Examples of this invention are those used for the crosslinking of the polymers obtained by radical polymerization. By way of example of such agents, mention may be made of divinylbenzene, diallyl ether, dipropyleneglycol-diallylether, polyglycol-diallylethers, triethyleneglycol-divinylether, hydroquinone-diallylether, tetralyloxethanoyl, derivatives thereof. polyfunctional allyl or vinylether alcohols, tetraethylene glycol diacrylate, triallylamine, trimethylolpropane diallyl ether, tetraallyloxyethane, methylenebisacrylamide, allyl ethers of alcohols of the sugar series, allyl methacrylate, trimethylol propane triacrylate (TMPTA) and mixtures thereof. Preferably, a noncrosslinked graft polymer backbone is used.

Among the polycondensates and natural or modified natural polymers that may constitute, in whole or in part, the water-soluble or water-dispersible units, mention may be made of: water-soluble polyurethanes,

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 xanthan gum, in particular that sold under the names Keltrol T and Keltrol SF by Kelco, or Rhodigel SM and Rhodigel 200 by Rhodia; alginates (Kelcosol from Monsanto) and their derivatives such as propylene glycol alginate (Kelcoloid LVF from Kelco); cellulose derivatives and especially carboxymethylcellulose (Aquasorb A500 Hercules), hydroxypropylcellulose, hydroxyethylcellulose and quaternized hydroxyethylcellulose, galactomannans and their derivatives such as Konjac gum, guar gum, hydroxypropylguar, hydroxypropylguar modified with sodium methylcarboxylate groups (Jaguar XC97-1, Rhodia) and hydroxypropyltrimethylammonium guar chloride, and polyethyleneimine.

Preferably, the water-soluble or water-dispersible units have a molar mass of from 1000 g / mol to 10,000,000 g / mol when they constitute the water-soluble backbone of a graft polymer.

These water-soluble or water-dispersible 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 units whose water solubility is altered at the same time are modified by the following methods: ## EQU1 ## ## STR1 ## ## STR2 ## beyond a certain temperature. These are units with a temperature of demixing by heating (or cloud point) defining their zone of solubility in the water. The minimum demixing temperature obtained as a function of the polymer concentration is called "LCST" (Lower Critical Solution Temperature). For each polymer concentration, a demixing temperature by heating is observed; it is greater than the LCST which is the minimum point of the curve.

Below this temperature, the polymer is soluble in water; above this temperature, the polymer loses its solubility in water. By water-soluble at temperature T, it is meant that the units have a solubility at T of at least 1 g / l, preferably at least 2 g / l.

The measurement of the LCST can be done visually. For example, the temperature at which the cloud point of the aqueous solution appears appears to be visually determined.

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 where, at this temperature, there is a clouding of the solution, or loss of transparency.

In general, a transparent composition will have a maximum light transmittance value, regardless of wavelength between 400 and 800 nm, through a 1 cm thick sample, of at least 85 %, preferably at least 90%. Transmittance can be measured by placing a 1 cm thick sample in the light beam of a spectrophotometer working in the wavelengths of the light spectrum.

The LCST units of the polymers used in the invention may consist of one or more of the following polymers: polyethers such as polyethylene oxide (POE), polypropylene oxide (POP), and random copolymers of ethylene oxide (EO) and propylene oxide (PO), polyvinylmethylethers, N-substituted copolymeric and polymeric derivatives of acrylamide having an LCST, polyvinylcaprolactam and copolymers of vinyl caprolactam.

-nombre-entier-allant-de--10-à-60,d préférence-de-2)L- #==zrr De préférence, la masse molaire de ces unités à LCST est de 500 à 5300 g/mole, de préférence de 1500 à 4000 g/mole. Preferably, the LCST units consist of random copolymers of ethylene oxide (EO) and propylene oxide (OP) represented by the formula: (EO) m (OP) n in which m is an integer ranging from 1 to 40, preferably 2 to 20, and n is a

Preferably, the molar mass of these LCST units is from 500 to 5300 g / mol, preferably from 10 to 60, preferably from-2 to 1, preferably from preferably from 1500 to 4000 g / mol.

It has been found that the statistical distribution of the EO and OP units results in the existence of a lower critical demixing temperature, beyond which macroscopic phase separation is observed. This behavior is different from that of OP block copolymers, which micellize beyond a critical temperature called micellization (aggregation at the microscopic scale).

The units with an LCST can thus notably be in the form of random copolymers of ethylene oxide and of propylene oxide, amines, in particular monoamines, diamines or triamines. Among commercially available LCST units, mention may be made of

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 the copolymers sold under the name Jeffamine by Hunsman, and in particular Jeffamine XTJ-507 (M-2005), Jeffamine D-2000 and Jeffamine XTJ-509 (or T-3000).

The units with an LCST can also be in the form of OH / OH statistical copolymers OE / OP, such as those sold under the name Polyglycols P41 and B11 by Clariant.

Advantageously, it is possible according to the invention to use polymers having LCST units, such as the N-substituted copolymeric and acrylamide derivatives of acrylamide having an LCST as well as poly N-vinylcaprolactam and copolymers of N-vinylcaprolactam.

-vil'lylformamide.-Ia-N-méthylvinylformamida-Ies- vinyléthers- et--leS::..dérivés-de-l'-a#1ata=de vinyle, l'acrylonitrile, la caprolactone, le chlorure de vinyle, le chlorure de vinylidène. As examples of N-substituted acrylamide derivatives, there may be mentioned poly N-isopropyl acrylamide, poly N-ethyl acrylamide and copolymers of N-isopropyl acrylamide or N-ethyl acrylamide and a monomer. vinyl compound having the formula (I) or (II) given above, or a monomer selected from (meth) acrylic acid, vinylsulfonic acid, (meth) allylsulfonic acid, acid and anhydride maleic acid, vinylphosphonic acid, crotonic acid, itaconic acid, (meth) acrylamide, vinylpyridine, vinyl alcohol, N-vinyllactams such as N-vinylpyrrolidone, styrene and its derivatives, chloride of dimethyldiallyl ammonium, N-vinylacetamide, N-methyl N-vinylacetamide, N-vinyl

N-methylvinylformamide-vinylethers and vinyl derivatives thereof, acrylonitrile, caprolactone, vinyl chloride, vinylidene chloride.

The molar mass of the N-substituted polymers and copolymers of acrylamide is preferably from 1000 g / mol to 500,000 g / mol.

The synthesis of these polymers can be carried out by radical polymerization using a pair of initiators such as aminoethanethiol hydrochloride in the presence of potassium persulfate in order to obtain oligomers having an amine reactive end.

Examples of copolymers of N-vinylcaprolactam include copolymers of N-vinylcaprolactam and a vinyl monomer corresponding to the formula (I) or (II) given above, or a monomer selected from (meth) acrylic acid, vinylsulfonic acid, (meth) allylsulfonic acid, maleic acid, maleic anhydride,

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 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, vinyl ethers, acrylonitrile, caprolactone, vinyl chloride and vinylidene chloride. The molar mass of these polymers is preferably from 1000 g / mol to 500 000 g / mol.

 The synthesis of these polymers can be carried out by radical polymerization using a pair of initiators such as aminoethanethiol hydrochloride in the presence of azobisisobutyronitrile to obtain oligomers having an amine reactive end.

The mass proportion of the LCST units in the final polymer is preferably from 5 to
70%, especially 20 to 65%, and particularly 30 to 60% by weight relative to the final polymer.

As defined above, the heating demixing temperature of the units with an LCST is 5 to 40 ° C., preferably 10 to 35 ° C. for a mass concentration of the units with
LCST in 1% water. The demixing temperatures are determined by spectroscopy
UV visible by measuring, at a wavelength equal to 500 nm, the absorbance of aqueous solutions comprising 1% by weight of said LSCT units. The demixing temperature is identified at the temperature at which the absorbance of the solution is 2.

The polymers used in the context of this invention can be easily prepared by those skilled in the art by various methods, such as grafting, copolymerization, coupling or living polymerization processes.

 For example, when the final polymer is in the form of a graft polymer having in particular a water-soluble backbone with lateral units at LCST, it is possible to prepare it by grafting the LCST units having at least one reactive end, for example amine, on a water-soluble polymer forming the backbone, said backbone bearing at least 10% (in mole) of reactive groups such as carboxylic acid functions. This reaction can be carried out in the presence of a carbodiimide such as dicyclohexylcarbodiimide or 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride in a solvent such as N-methylpyrrolidone or water.

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 Another possibility for preparing graft polymers is to copolymerize for example an LCST macromonomer (previously described unit with an unsaturated end) and a water-soluble vinyl monomer such as acrylic acid or vinyl monomers having the formula (I) mentioned above.

When the final polymer is in the form of a block polymer, it can be prepared by coupling between water-soluble or water-dispersible units and
LCST having complementary reactive sites at each end.

It is also possible to prepare such polymers by living polymerization of anionic or cationic type, or by controlled radical polymerization. This last synthesis process can be implemented by various methods such as the Atom Transfer Radical Polymerization (ATRP) method, the radicals method such as nitroxides or by the reversible chain transfer method with addition-fragmentation (Radical Addition-Fragmentation Chain Transfer) such as the MADIX process (Macromolecular Design via the Interchange of Xanthate). These methods can be used to obtain the water-soluble blocks and the LCST blocks of the polymers used in the context of the invention. They can also be used to synthesize only one of the two types of blocks of the polymer used according to the invention, the other block being introduced into the final polymer via the initiator used or by coupling reaction between the blocks. Water-soluble and at LCST - - - @
As indicated above, the composition according to the invention containing the LCST-unit polymer described above does not contain any other optically-active compound belonging to any of the following categories: fillers, pearlescent agents, pigments, polymers mattifying agents and tensors.

 The absence of such compounds in the composition used according to the invention not only does not surprisingly affect the optical properties of the composition when applied to the skin, but also offers the formulator of cosmetics the possibility of to formulate transparent compositions that can not be obtained from fillers or latex, for example, which impart a white appearance to these compositions.

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By fillers, it is necessary to understand colorless or white particles, mineral or organic, lamellar or non-lamellar, cylindrical, capable of giving body or stiffness to the composition and / or softness, dullness and uniformity make-up.

As fillers, there may be mentioned talc, mica, silica, boron nitride, bismuth oxychloride, kaolin, nylon powders such as nylon-12 (Orgasol marketed by Atochem), powders polyethylene, Teflon (tetrafluoroethylene polymer powders), polyurethane powders, polystyrene powders, polyester powders, optionally modified starch, microspheres of copolymers, such as those sold under the names Expancel by the company Nobel Industry, micro-sponges such as Polytrap marketed by Dow Corning, silicone resin microbeads such as those sold by Toshiba under the name Tospearl, precipitated calcium carbonate, carbonate and magnesium hydrocarbonate, hydroxyapatite, hollow silica microspheres (Silica Beads from the Maprecos Company), microcapsules of glass or ceramics that, the fibers composed for example of polyamide 6-6, metal soaps derived from organic carboxylic acids having from 8 to 22 carbon atoms, preferably from 12 to 18 carbon atoms, for example zinc stearate, magnesium or lithium, zinc laurate, magnesium myristate, and mixtures thereof.

By nacres, we must understand iridescent particles that reflect light. Among the nacres that can be envisaged, mention may be made of natural mother-of-pearl, mica coated with titanium oxide, with iron oxide, with natural pigment or with bismuth oxychloride, and with colored titanium mica.

 By pigments, one must understand white or colored particles, mineral or organic, insoluble in the medium, capable of coloring and / or opacifying the composition. They may be white or colored, inorganic and / or organic, of usual or nanometric size. Among the pigments and mineral nanopigments, titanium, zirconium or cerium dioxides, as well as zinc, iron or chromium oxides, nanotitans (nanopigments of titanium dioxide), nanozincs (nanopigments) zinc oxide), ferric blue. Among the organic pigments, mention may be made of carbon black, and lacquers such as calcium, barium, aluminum or zirconium salts, acid dyes such as halo-acid, azo or anthraquinone dyes.

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 Matifying polymers are any polymer in solution, in dispersion or in the form of particles, which prevents the skin from shining and unifies the complexion. More specifically, the term "mattifying polymer" means a compound which, introduced into a cosmetic composition applied to a rubber substrate at a rate of 2 mg / cm 2, leads to a reduction in the ratio of the specular and diffuse reflections, measured using a gonioreflectometer at 20 C, at least 5% with respect to the same composition not comprising this compound. Mention may be made, as examples of mattifying polymers, of silicone elastomers; resin particles; acrylic styrene copolymers (Ropaque OP 3000 marketed by Rohm and Haas) and copolymers of vinylpyrrolidone triacontene (Antaron WP 660 supplied by ISP); and their mixtures As silicone elastomers, mention may be made, for example, of the products sold under the names KSG by the company Shin-Etsu, under the names Trefil, BY29 or EPSX by the company Dow Corning or under the names Gransil by the company Grant Industries .

Examples of resin particles that may be mentioned include those of melamine formaldehyde resin or urea-formaldehyde resin disclosed in EP-A-1,046,388.

jenselJrS, or peliLciterle.S-poJD1ère5-dorigjl1eJlatu#lla1eJs---que...décdts---par-exemple-daAS--le-.- document EP-912165; les polymères synthétiques se présentant sous forme de latex et pseudolatex comme ceux décrits dans le document EP-A-944381 ; les polymères dendritiques tels que décrits dans le document EP-A-987016 ; les polymères de structure en "étoiles" tels que décrits dans le document EP-A-1,043,345 ; les silicates mixtes; les dispersions colloïdales de minéraux ; et leurs mélanges. By tightening agent, it is necessary to understand compounds that may have a tensor effect, that is to say, may tend the skin and, by this tension effect, smooth the skin and reduce or even disappear immediately wrinkles and fine lines. As agents

jenselJrS, or peliLciterle.S-pojD1ère5-dorigjl1eJlatu #lla1eJs --- that ... decdts --- by-example-DAAS - the document EP-912165; synthetic polymers in the form of latex and pseudolatex such as those described in EP-A-944381; dendritic polymers as described in EP-A-987016; "star" structure polymers as described in EP-A-1,043,345; mixed silicates; colloidal dispersions of minerals; and their mixtures.

The polymer according to the invention will be present in the cosmetic composition containing it in an amount effective to obtain the desired effect. By way of example, for an application to the skin, this polymer preferably represents from 0.01 to 20%, better still from 0.1 to 15% and more preferably from 0.5 to 5% of the total weight. of the composition.

The composition according to the invention may be more or less fluid and have the appearance of a white or colored cream, an ointment, a milk, a lotion, a serum or an aqueous solution. transparent which can be more or less gelled, a paste, a mousse. She

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 may optionally be applied to the skin as an aerosol or patch. It can also be in solid form, in particular in the form of a stick for the lips or lipstick. It can be used as a care product and / or as a makeup product for the skin or lips.

In a known manner, the composition according to the invention may also contain the usual adjuvants in the cosmetic field, such as hydrophilic or lipophilic gelling agents, hydrophilic or lipophilic active agents, preservatives, antioxidants, solvents, perfumes, filters, odor absorbers and dyestuffs. The amounts of these various adjuvants are those conventionally used in the field under consideration, and for example from 0.01 to 20% of the total weight of the composition. These adjuvants, depending on their nature, can be introduced into the fatty phase or into the aqueous phase. In any case, these adjuvants, as well as their proportions, will be chosen so as not to interfere with the desired properties of the polymer according to the invention.

The composition according to the invention may be in any galenical form normally used in the cosmetics field, and it may especially be in the form of an optionally gelled aqueous solution, an emulsion obtained by dispersion of a fatty phase in a aqueous phase (O / W) or conversely (W / O), a triple emulsion (W / H / E or H / E / H), an ionic-type vesicular dispersion (liposomes or oleosomes) and / or nonionic (niosomes) and / or dispersion of nanocapsules or nanospheres.

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

When the composition of the invention is an emulsion, the proportion of the fatty phase can range from 2 to 80% by weight, and preferably from 5 to 50% by weight relative to the total weight of the composition. The oils, emulsifiers and coemulsifiers used in the composition in emulsion form are chosen from those conventionally used in the field under consideration. The emulsifier and the co-emulsifier are generally present in the composition in a proportion ranging from 0.3 to 30% by weight, and preferably from 0.5 to
20% by weight relative to the total weight of the composition. Alternatively, the composition according to the invention in emulsion form may not contain emulsifier.

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- les alcools gras aKad~e à~2atolnas~dcar~~b~neT~cmme~LaIcnoLcéiyliquel~'afcoJ-- stéarylique et leur mélange (alcool cétylstéarylique), l'octyldodécanol, le 2-butyloctanol, le 2hexyldécanol, le 2-undécylpentadécanol, l'alcool oléique ou l'alcool linoléique ; - les huiles fluorées partiellement hydrocarbonées et/ou siliconées comme celles décrites dans le document JP-A-2-295912 ; - les huiles de silicone comme les polyméthylsiloxanes (PDMS) volatiles ou non à chaîne siliconée linéaire ou cyclique, liquides ou pâteux à température ambiante, notamment les cyclopolydiméthylsiloxanes (cyclométhicones) telles que la cyclohexasiloxane ; les polydiméthylsiloxanes comportant des groupements alkyle, alcoxy ou phényle, pendant ou en bout de chaîne siliconée, groupements ayant de 2 à 24 atomes de carbone ; silicones phénylées comme les phényltriméthicones, les phényldiméthicones, les phényltriméthylsiloxydiphényl-siloxanes, les diphényl-diméthicones, les As oils that can be used in the composition of the invention, mention may be made, for example, of: hydrocarbon-based oils of animal origin, such as perhydrosqualene; hydrocarbon oils of vegetable origin, such as liquid triglycerides of fatty acids containing from 4 to 10 carbon atoms and the liquid fraction of shea butter; esters and synthetic ethers, in particular of fatty acids, such as the oils of formulas R'COOR2 and R1OR2 in which R1 represents the residue of a fatty acid comprising from 8 to 29 carbon atoms, and R2 represents a hydrocarbon-based chain, branched or unbranched, containing from 3 to 30 carbon atoms, such as for example purcellin oil, isononyl isononanoate, isopropyl myristate, 2-ethylhexyl palmitate, octyl stearate -2-dodecyl, octyl-2-dodecyl erucate, isostearyl isostearate; hydroxylated esters such as isostearyl lactate, octyl hydroxystearate, octyldodecyl hydroxystearate, diisostearyl malate, triisocetyl citrate, heptanoates, octanoates, decanoates of fatty alcohols; polyol esters, such as propylene glycol dioctanoate, neopentyl glycol diheptanoate and diethylene glycol diisononanoate; and pentaerythritol esters such as pentaerythrityl tetraisostearate; linear or branched hydrocarbons of mineral or synthetic origin, such as paraffin oils, volatile or not, and their derivatives, petroleum jelly, polydecenes, hydrogenated polyisobutene such as parleam oil;

the fatty alcohols are alkali-2-alkenyl carbonic alcoholic alcohols and their mixture (cetyl-stearyl alcohol), octyldodecanol, 2-butyloctanol, 2-oxyldecanol, 2- undecylpentadecanol, oleic alcohol or linoleic alcohol; partially fluorinated hydrocarbon oils and / or silicone oils such as those described in document JP-A-2-295912; silicone oils such as volatile or non-volatile polymethylsiloxanes (PDMS) with a linear or cyclic silicone chain, which are liquid or pasty at room temperature, in particular cyclopolydimethylsiloxanes (cyclomethicones) such as cyclohexasiloxane; polydimethylsiloxanes comprising alkyl, alkoxy or phenyl groups, during or at the end of the silicone chain, groups having from 2 to 24 carbon atoms; phenyl silicones such as phenyltrimethicones, phenyldimethicones, phenyltrimethylsiloxydiphenylsiloxanes, diphenyl dimethicones,

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 diphenylmethyldiphenyl trisiloxanes, 2-phenylethyltrimethylsiloxysilicates, and polymethylphenylsiloxanes; - their mixtures.

The other fatty substances that may be present in the oily phase are, for example, fatty acids containing from 8 to 30 carbon atoms, such as stearic acid, lauric acid, palmitic acid and oleic acid; waxes such as lanolin, beeswax, carnauba or candelilla wax, paraffin waxes, lignite waxes or microcrystalline waxes, ceresin or ozokerite, synthetic waxes such as polyethylene waxes, waxes Fischer-Tropsch; gums such as silicone gums (dimethiconol); silicone resins such as trifluoromethyl-C1-4-alkyldimethicone and trifluoropropyldimethicone; and silicone elastomers such as the products sold under the names KSG by the company Shin-Etsu, under the names Trefil, BY29 or EPSX by the company Dow Corning or under the names Gransil by the company Grant Industries.

These fatty substances may be chosen in a varied manner by those skilled in the art in order to prepare a composition having the desired properties, for example of consistency or texture.

The emulsifying surfactants are appropriately selected according to the emulsion to be obtained (W / O or O / W).

For the O / W emulsions, a nonionic emulsifying surfactant, such as esters and ether esters such as sucrose stearate, sucrose cocoate, and sorbitan stearate mixture, may be used as emulsifying surfactant. sucrose cocoate sold by ICI under the name Arlatone 2121; polyol esters, especially of glycerol or of sorbitol, such as glyceryl stearate, polyglyceryl-2 stearate, sorbitan stearate; glycerol ethers; oxyethylenated and / or oxypropylenated ethers such as the oxyethylenated, oxypropyleneated ether of oxyethylenated lauric alcohol and oxypropylene groups (CTFA name PPG-25 laureth-25) and the oxyethylenated ether of the fatty alcohol mixture in C12-C15 having 7 oxyethylenated groups (CTFA name C12-C15 Pareth-7); ethylene glycol polymers, such as
PEG-100, and mixtures thereof.

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For the W / O emulsions, mention may be made, for example, as an emulsifying surfactant, of the polyol fatty esters, in particular of glycerol or of sorbitol, and in particular the isostearic, oleic and ricinoleic esters of polyol, such as the petrolatum mixture, polyglyceryl-3 oleate, glyceryl isostearate, hydrogenated castor oil and ozokerite, sold under the name PROTEGIN W # by Goldschmidt, sorbitan isostearate, polyglyceryl di-isostearate, sesqui polyglyceryl isostearate; esters and ethers of monosaccharides such as methyl glucose dioleate; fatty esters such as magnesium lanolate; dimethicone copolyols and alkyl-dimethicone copolyols such as Laurylmethicone copolyol sold under the name DOW CORNING 5200 FORMULATION AID by Dow Corning and Cetyl dimethicone copolyol sold under the name ABIL EM 90 # by the company Goldschmidt, and mixtures thereof.

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

It is also possible to use, as emulsifiers, amphiphilic polymers such as modified acrylic copolymers, for example the products marketed under the names Pemulen by the company Goodrich; copolymers of 2-acrylamido-2-methylpropanesulphonic acid with a hydrophobic chain, as described in document EP-A-1 069 142; the optionally esterified or amidified succinic-terminated polyolefins, 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; -4919179. As succinic-terminated polyolefins, mention may be made especially of polyisobutylenes with a modified succinic terminus, such as the products sold under the names L2724 and
L2721 by the company Lubrizol.

 The amount of emulsifying surfactant may range from 0 to 1% in emulsions known to be free of emulsifying surfactant. In the other emulsions, the amount of emulsifiers (surfactant or polymer) can range from 0.01 to 10% of the total weight of the composition.

 As hydrophilic gelling agents, mention may in particular be made of carboxyvinyl polymers (carbomer) and acrylic copolymers such as acrylate / alkylacrylate copolymers.

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 (Pemulen), polyacrylamides in particular derived from acrylamido-2-methylpropanesulphonic acid (Hostacerin AMPS supplied by Clariant and Sepigel 305 supplied by Seppic), polysaccharides such as cellulose derivatives, natural gums and clays, and lipophilic gelling agents that may be mentioned are modified clays, such as bentones, metal salts of fatty acids, hydrophobic silica and polyethylenes.

For use in the cosmetic treatment of oily or combination skin, the composition according to the invention will preferably contain at least one active agent chosen from: vitamins B3 and B5; zinc salts, and in particular zinc oxide and zinc gluconate; salicylic acid and its derivatives such as n-octanoyl-5-salicylic acid; antibacterial active agents such as 2,4,4'-trichloro-2'-hydroxy diphenyl ether (triclosan); capryloylglycine; an extract of clove; octopirox; hexamidine; and azelaic acid and its derivatives. The composition may further contain the following active agents: moisturizing agents and for example protein hydrolysates and polyols such as glycerin, glycols such as polyethylene glycols, and sugar derivatives; natural extracts; anti-inflammatories; procyannidol oligomers; vitamins such as vitamin A (retinol), vitamin C (ascorbic acid), vitamin E (tocopherol), derivatives of these vitamins (especially esters) and mixtures thereof; urea; caffeine; depigmenting agents such as kojic acid, hydroquinone and caffeic acid; salicylic acid and its derivatives; alpha-hydroxy acids such as lactic acid and glycolic acid and their derivatives; retinoids such as carotenoids and vitamin A derivatives; hydrocortisone; melatonin; extracts of algae, mushrooms, vegetables, yeasts, bacteria; enzymes; DHEA and its derivatives and metabolites; 3,4,4'-trichlorocarbanilide (or triclocarban) and the acids indicated above; and their mixtures.

 In the event of incompatibility or to stabilize them, at least some of the assets mentioned above may be incorporated in spherules, in particular ionic or nonionic vesicles and / or nanoparticles (nanocapsules and / or nanospheres).

 The sunscreens may be selected from chemical filters, physical filters and mixtures thereof.

 As chemical sunscreens, there may be mentioned for example:

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 butylmethoxydibenzoylmethane sold in particular by Hoffmann-Laroche under the name Parsol 1789, octocrylene sold in particular by BASF under the name Uvinul N539, octylsalicylate sold by Haarman-Reimer under the name Neo Heliopan. OS, - octylmethoxycinnamate sold in particular by the company Hoffmann-Laroche under the name Parsol MCX, - phenylbenzimidazole sulfonic acid sold in particular by Merck under the name Eusolex 232, - oxybenzones such as benzophenones-3, -4 or -5, - benzotriazole silicones and in particular trisiloxane drometzol, - terephthalylidene di-camphorsulfonic acid, in particular Mexoryl SX sold by the company Chimex, - benzotriazole silicones, in particular those described in application FR-A- 2,642,968, as well as insoluble organic filters such as triazine derivatives, and in particular 2,4-bis [4- (2- thyl-hexyloxy) -2-hydroxy-phenyl-6- (4-methoxy-phenyl) -1,3,5-triazine available from CIBA GEIGY under the tradename TINOSORB S, and 2,2 ' -methylenebis- [6- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) -phenol] available from CIBA GEIGY under the tradename TINOSORB M.

As physical sunscreens, mention may be made, for example, of titanium or zinc oxides, in the form of optionally coated micro- or nanoparticles (nanopigments), and mixtures thereof. There may be mentioned, for example, the hydrophilic nanotitanium sold under the name MIRASUN TIW60 by the company Rhodia, and the lipophilic nanotitanium sold under the name MT100T by the company Tayca.

 The invention will be better understood and its advantages will emerge more clearly, in the light of the following examples which are given by way of illustration and without limitation.

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EXAMPLES Example 1: Matifying cream Aqueous phase Sodium polyacrylate 450,000 g / mole bearing Jeffamine M-2005 grafts (random copolymer of ethylene oxide (6) and propylene oxide (39)); molar grafting rate = 3.9% *
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 Dimyristyl tartrate / cetearyl alcohol mixture / 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 * 1% demixing temperature in water units Jeffamine M-2005 is 25 C. The gelling temperature at 2% by weight in water of this polymer is 28 C.

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

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EXAMPLE 2 Demonstration of Optical Properties Protocol: Four compositions A to D were tested, where: 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 molar grafting level of 2% (the gelling temperature at 2% by weight in the water of this polymer is 33 ° C.), the composition C was identical to that of the Example 1, except that the aqueous phase polymer was replaced by the same amount of silica microspheres (Silica Beads SB 150 MIYOSHI), and - the composition D was identical to that of Example 1, except that it did not contain of polymer in aqueous phase, the amount of water being increased accordingly.

The principle of the method is to measure using a gonioreflectometer specular reflection and diffuse reflection of a deposit of each composition to be evaluated, previously spread at temperature T on a rubber support at a rate of 2 mg / ml. cm2. The deposits are then dried at the temperature T for 30 minutes. The spreading and drying phases were carried out at two temperatures: 20 C and 37 C in order to demonstrate the influence of temperature on the optical properties of the compositions.

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

 An optical effect sufficient to modify the appearance of the skin and to make the complexion matte and homogeneous is obtained when this ratio R is at most 1.9 and preferably less than 1.6, whereas a ratio R greater than 2, and especially greater than 2.2, is considered to reflect a lack of improvement in the appearance of the skin.

Results:
The results obtained for the four compositions tested are summarized in the following table:

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<Tb>
<tb> Composition <SEP> R <SEP> (20 C) <SEP> R <SEP> (37 C)
<tb> A <SEP> 1.84 <SEP> 1.53 <SEP>
<tb> B <SEP> 1.44 <SEP> 1.50 <SEP>
<tb> C <SEP> 2.01 <SEP> 2.16
<tb> D <SEP> 2.06 <SEP> 2.26
<Tb>
It is thus clear from the above table that only the compositions A and B according to the invention make it possible to homogenize the appearance of the skin, in particular to camouflage the pores and the rings and to mattify the complexion. These properties of the compositions according to the invention are maintained (Composition B) or further reinforced (Composition A) during a temperature rise, corresponding to the transition from the conditioning temperature to the temperature of the skin.

In addition, the gelling power of composition A is 1200 Pa at 20 C (0.1 s-1) and 3000 Pa at 32 C (0.1 s-1) and that of composition B is 1000 Pa at 20 C (0.1 s-1) and 2500 Pa s at 32 C (0.1 s-1). These compositions are therefore both relatively fluid to the touch and thicker to the application on the skin, which makes their application easy and pleasant.

Claims (23)

 1. Cosmetic use, in a composition comprising a physiologically acceptable medium, as an agent for mattifying the skin and / or for concealing the rings and / or for concealing the pores, of at least one water-soluble or water-dispersible polymer comprising water-soluble or water-dispersible units and units with LCST, said units with LCST having in water a demixing temperature (or cloud point) of 5 to 40 C at a mass concentration of 1%, said composition being free from any other compound optical effect chosen from fillers, nacres, pigments, mattifying polymers and tensors. 2. Use, in the cosmetic treatment of oily or combination skin, of a composition containing, in a physiologically acceptable medium, at least one water-soluble or water-dispersible polymer comprising water-soluble or water-dispersible units and units with LCST, said LCST units having in water a demixing temperature (or cloud point) of 5 to 40 ° C at a mass concentration of 1%, said composition being free from any other optically selected compound selected from fillers, pearlescent agents, pigments, mattifying polymers and tensors. 3. Use according to claim 2, characterized in that said composition is in the form of an oil-in-water emulsion. 4. Use according to claim 2, characterized in that the composition also contains at least one active agent chosen from: vitamins B3 and B5; zinc salts, and in particular zinc oxide and zinc gluconate; salicylic acid and its derivatives such as n-octanoyl-5-salicylic acid; triclosan, capryloylglycine; an extract of clove; octopirox; hexamidine; and azelaic acid and its derivatives. 5. Use according to any one of claims 1 to 4, wherein the polymer has a gelling temperature of 5 to 50 C for a mass concentration in water of 2%.  The use according to any one of claims 1 to 5, wherein the polymer is in the form of a block polymer (or blocks) comprising water-soluble or water-dispersible units and alternating LCST units or in the form of a <Desc / Clms Page number 25>  graft polymer consisting of an optionally crosslinked skeleton formed of water-soluble or water-dispersible units and carrying grafts consisting of LCST units or vice versa. 7. Use according to any one of claims 1 to 6, wherein the water-soluble or water-dispersible units of the polymer, in whole or in part, are obtained by polymerization of at least one water-soluble monomer or its salt chosen from: - acid (meth) acrylic; vinylsulfonic acid; - (meth) allylsulfonic acid; vinylphosphonic acid; methyl vinylimidazolium chloride; (meth) acrylamide; 2-vinylpyridine, 4-vinylpyridine; maleic acid and anhydride; crotonic acid; - itaconic acid; vinyl acid of formula CH 2 = CHOH; N-vinyllactams having a cyclic alkyl group of 4 to 9 carbon atoms such as N-vinylpyrrolidone, N-vinylcaprolactam and N-butyrolactam; water-soluble derivatives of styrene, in particular styrene sulphonate; dimethyldiallyl ammonium chloride; N-vinylacetamide and N-methyl, N-vinylacetamide; N-vinylformamide and N-methyl-N-vinylformamide.  in which: - R is chosen from H, -CH3, -C2H5 or -C3H7, and - X is chosen from: - alkyl oxides of -OR 'type where R' is a hydrocarbon radical, linear or branched, saturated or unsaturated, having from 1 to 6 carbon atoms, substituted by at least one group selected from halogen atoms (iodine, bromine, chlorine, fluorine); sulphonic groups (-

 the vinyl monomers of formula (I) below: <Desc / Clms Page number 26>  SO3-), sulfate (-SO4-), phosphate (-PO4H2-); hydroxy (-OH); ether (-O-); primary amine (NH2); secondary amine (-NHR 4), tertiary (NR 1 R 2) or quaternary (-N + R 1 R 2 R 3) with R 1, R 2 and R 3 being, independently of each other, a linear or branched, saturated or unsaturated hydrocarbon radical having 1 to 6 carbon atoms, provided that the sum of the carbon atoms of R '+ R1 + R2 + R3 does not exceed 7; and the -NH2, -NHR4 and -NR4R5 groups in which R4 and R5 are independently of each other linear or branched, saturated or unsaturated hydrocarbon radicals having 1 to 6 carbon atoms, provided that the number total of carbon atoms of R4 + R5 does not exceed 7, said R4 and R5 being substituted by at least one group selected from halogen atoms (iodine, bromine, chlorine, fluorine); hydroxy groups (-OH); sulfonic (-SO3-); sulfate (-SO4-); phosphate (-PO4H2-); primary amine (-NH2); secondary amine (NHRi), tertiary (-NR1R2) and / or quaternary (-N + R1R2R3) with R1, R2 and R3 being, independently of one another, a linear or branched, saturated or unsaturated hydrocarbon radical having 1 to 6 carbon atoms, provided that the sum of the carbon atoms of R4 + R5 + R1 + R2 + R3 does not exceed 7; 8. Use according to any one of claims 1 to 6, wherein the water-soluble or water-dispersible units of the polymer, in whole or in part, are obtained by copolymerisarion of at least one hydrophobic monomer with at least one water-soluble monomer, said hydrophobic monomer being in such a quantity that the resulting units are water-soluble or water-dispersible, said hydrophobic monomer being chosen from: styrene and its derivatives such as 4-butylstyrene, alpha-methylstyrene and vinyltoluene; vinyl acetate of formula CH2 = CH-OCOCH3; vinyl ethers of formula CH2 = CHOR6, in which R6 is a linear or branched, saturated or unsaturated hydrocarbon-based radical containing from 1 to 6 carbon atoms; acrylonitrile; caprolactone; vinyl chloride and vinylidene chloride; silicone derivatives, such as methacryloxypropyltris (trimethylsiloxy) silane, silicone methacrylamides, and hydrophobic vinyl monomers of formula (II) below: <Desc / Clms Page number 27>  in which: - R7 is chosen from H, -CH3, -C2H5 or C3H7, - X1 is chosen from: - alkyl oxides of type -ORB where R8 is a linear or branched, saturated or unsaturated hydrocarbon radical, having from 1 to 22 carbon atoms; the groups NH 2, -NHR 9 and -NR 9 R 10 in which R 8 and R 10 are, independently of each other, linear or branched, saturated or unsaturated hydrocarbon radicals having 1 to 22 carbon atoms, provided that the total number of carbon atoms of Rg + R10 does not exceed 23.

9. Use according to claims 7 or 8, wherein the water-soluble or water-dispersible units of the polymer are neutralized, in whole or in part with a mineral or organic base selected from sodium, ammonium, lithium, calcium, magnesium, ammonium substituted by 1 to 4 alkyl groups having 1 to 15 carbon atoms, mono, di- and triethanolamine, aminoethylpropanediol, N-methylglucamine, basic amino acids such as arginine and lysine, and their mixtures. 10. Use according to any one of claims 7 to 9, wherein the water-soluble or water-dispersible units of the polymer are crosslinked by action of at least one compound selected from divinylbenzene, diallyl ether, dipropylene glycol diallyl ether, polyglycol diallyl ethers, triethylene glycol divinyl ether, hydroquinone diallyl ether, tetralyl oxethanoyl, allyl or vinyl ether derivatives of polyfunctional alcohols, tetraethylene glycol diacrylate, triallylamine, trimethylolpropane diallylether, tetraallyloxyethane, methylenebis acrylamide, allyl ethers of alcohols of the series of sugars, methylene-bis-acrylamide, allyl methacrylate, trimethylolpropane triacrylate (TMPTA), and mixtures thereof. <Desc / Clms Page number 28> 11. Use according to any one of claims 1 to 6, wherein the water-soluble or water-dispersible units of the polymer consist in whole or in part of one or more of the following components: - water-soluble polyurethanes, - xanthan gum, alginates and their derivatives such as propylene glycol alginate, cellulose derivatives and in particular carboxymethylcellulose, hydroxypropylcellulose, hydroxyethylcellulose and quaternized hydroxyethylcellulose, galactomannans and their derivatives such as Konjac gum, guar gum, hydroxypropylguar, hydroxypropylguar modified with sodium methylcarboxylate groups, and hydroxypropyltrimethylammonium guar chloride, and polyethyleneimine. Use according to any one of claims 1 to 11, wherein the water-soluble or water-dispersible units have a molar mass of from 1000 g / mol to 10,000,000 g / mol when they constitute the water-soluble skeleton of a polymer. grafted, or a molar mass ranging from 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, wherein the units to LCST consist of one or more of the following polymers: polyethers such as polyethylene oxide (POE), propylene polyoxide (POP), and random copolymers of ethylene oxide (EO) and propylene oxide (PO), polyvinyl methyl ether, N-substituted polymeric and copolymeric derivatives of acrylamide having an LCST; and poly N-vinylcaprolactam and copolymers of N-vinylcaprolactam.  The use according to claim 13, wherein the LCST units are random copolymers of ethylene oxide (EO) and propylene oxide (PO) represented by the formula:

<Desc / Clms Page number 29>  wherein m is an integer from 1 to 40, preferably 2 to 20, and n is an integer from 10 to 60, preferably from 20 to 50. 15. Use according to claim 14, wherein the molar mass of the LCST units is 500 to 5300 g / mol, preferably 1500 to 4000 g / mol. The use according to claim 13, wherein the LCST units are N-substituted acrylamide or copolymeric derivatives of acrylamide having an LCST such as poly N-isopropyl acrylamide, poly N-ethyl acrylamide and N copolymers. isopropyl acrylamide or N-ethyl acrylamide and a vinyl monomer corresponding to formula (I) or (II) given in claim 7 or 8, or a monomer selected from (meth) acrylic acid, vinylsulfonic acid, (meth) allylsulfonic acid, maleic acid and anhydride, vinylphosphonic acid, crotonic acid, itaconic acid, (meth) acrylamide, vinylpyridine, vinyl alcohol, N-vinyllactams such as Nvinylpyrrolidone, styrene and its derivatives, dimethyldiallyl ammonium chloride, Nvinylacetamide, N-methyl-N-vinylacetamide, N-vinylformamide, N-methylvinylformamide, vinyl ethers and derivatives thereof. vinyl acetate, acrylonitrile, ca prolactone, vinyl chloride, vinylidene chloride.  17. Use according to claim 16, wherein said derivatives have a molar mass ranging from 1000 g / mole to 500,000 g / mole.  18. Use according to claim 13, wherein the units with LCST are constituted by a poly-N-vinylcaprolactam or a copolymer of N-vinylcaprolactam and a vinyl monomer corresponding to the formula (I) or (II) given in the Claim 7 or 8, or a monomer selected from (meth) acrylic acid, vinylsulfonic acid, (meth) allylsulfonic 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, vinyl ethers, acrylonitrile, caprolactone, vinyl chloride, vinylidene chloride. <Desc / Clms Page number 30>  19. Use according to claim 18, wherein the molar mass of the units with LCST is from 1000 glmol to 500 000 g / mol. 20. Use according to any one of claims 1 to 19, wherein the mass proportion of the LCST units of the polymer is 5 to 70%, preferably 20 to 65% and more preferably 30 to 60% relative to polymer. 21. Use according to any one of claims 1 to 20, wherein the demixing temperature of the units at LCST is 10 to 35 C for a mass concentration of units in LCST in water of 1%. 22. Use according to any one of claims 1 to 21, wherein the polymer is from 0.01 to 20%, preferably from 0.1 to 15%, of the total weight of the composition. 23. Use according to any one of the preceding claims, characterized in that said composition is a transparent aqueous solution.