FR3026299A1 - COSMETIC PROCESS FOR ATTENUATING WRINKLES - Google Patents

Abstract

The invention relates to a cosmetic process for wrinkled skin, comprising either the topical application to the skin of an extemporaneous mixture of a cosmetic composition comprising a polysaccharide polymer grafted with (meth) acrylate groups and a crosslinking thiol compound having one or more thiol groups; or the sequential application on the skin of a cosmetic composition comprising a polysaccharide polymer grafted with (meth) acrylate groups, followed by the application of a crosslinking thiol compound having one or more thiol groups, or a cosmetic composition on container. The invention also relates to the use of the mixture of said grafted polysaccharide polymer and said crosslinking thiol as a skin tightening agent. The invention also relates to a cosmetic composition obtained by mixing a cosmetic composition comprising said grafted polysaccharide polymer and said crosslinking thiol. The invention relates to a kit comprising a first cosmetic composition comprising said grafted polysaccharide polymer and a second composition comprising said crosslinking thiol, the first and second compositions being each packaged in a separate packaging unit.

Description

The present invention relates to a method, especially a cosmetic skin care method, for attenuating wrinkles, comprising applying to the skin of the mixture a composition comprising a grafted polysaccharide polymer and a particular crosslinking thiol compound, and the use of this mixture as a skin tightening agent.

During the aging process, there are various signs on the skin, very characteristic of this aging, resulting in particular in a modification of the structure and cutaneous functions. The main clinical signs of skin aging include the appearance of fine lines and deep wrinkles, which increases with age. It is known to treat these signs of aging by using cosmetic or dermatological compositions containing active agents capable of combating aging, such as α-hydroxy acids, p-hydroxy acids and retinoids. These active agents act on wrinkles by eliminating dead skin cells and accelerating the process of cell renewal. However, these assets have the disadvantage of being effective for the treatment of wrinkles after a certain time of application. However, we seek more and more to obtain an immediate effect of the assets used, leading quickly to a smoothing of lines and wrinkles and the disappearance of fatigue marks.

The inventors have discovered that a polysaccharide polymer grafted with (meth) acrylate groups associated with a particular thiol compound, applied to the skin, has a good tensor effect on the skin and thus makes it possible to attenuate the wrinkles of the skin so that immediate. In addition, this tensor effect has good water resistance and therefore good water retention. The tensor effect is also resistant to sweat, and to the mechanical stresses induced by the movement of the skin. Polymers of hyaluronic acid grafted with (meth) acrylate groups are described in documents VVO 2007/106738 and publications J. Burdick et al. Controlled degradation and mechanical behavior photopolymerized hyaluronic acid networks, Biomacromolecules, 2005, 6, pages 386. -391; Mark Grinstaff "Photocrosslinkable polysaccharides for in situ hydrogel formation", Journal of Biomedical Materials Research, 2001, Volume 55, Issue 2, pages 115-121. They used to form after crosslinking hydrogels.

Dextran polymers grafted with methacrylate groups are described in WO2010 / 083039. They used in combination with riboflavin and arginine or chitosan to form after crosslinking under UV exposure or visible light hydrogels that are applied to the skin.

S.H.Kim, "Synthesis and characterization of dextran-methacrylate hydrogels and structural study by SEM" J. Biomed Mater Res, 49 (2005) 517 describes hydrogels obtained by photocrosslinking with UV exposure of dextran methacrylate.

Carrageenans are known for their tensor properties of the skin, especially in FR-A-2838343. More specifically, the subject of the present invention is a process, in particular a cosmetic method, for the care of the skin, more particularly of the skin of the face, in particular of the wrinkled skin, comprising: either the topical application on the skin of an extemporaneous mixture of a composition, in particular a cosmetic composition, comprising at least one, preferably a polysaccharide polymer grafted with (meth) acrylate groups and at least one, preferably a crosslinking thiol compound having one or more thiol groups; or the sequential application on the skin of a composition A, in particular a cosmetic composition, comprising at least one, preferably a polysaccharide polymer grafted with (meth) acrylate groups, followed by the application of at least one, preferably one crosslinking thiol compound having one or more thiol groups, or a composition B, especially a cosmetic composition, containing it.

The subject of the invention is also the use, in particular as a cosmetic, of a skin-tightening agent, in particular of a wrinkled skin, of a grafted polysaccharide polymer as defined above, or of a composition, in particular cosmetic, the container, mixed with the crosslinking thiol compound as defined above.

The subject of the invention is also a composition, in particular a cosmetic composition, obtained by mixing a composition, in particular a cosmetic composition, comprising a grafted polysaccharide polymer as defined above and a crosslinking thiol compound as defined above or a composition, especially cosmetic, the container.

The subject of the invention is also a kit comprising a first composition (composition A), in particular a cosmetic composition, comprising a grafted polysaccharide polymer as defined above and a second composition (composition B), in particular a cosmetic composition, comprising a crosslinking thiol compound as described. previously, the first and second compositions being each packaged in a separate package. The packaging assembly of the compositions is in a known manner any packaging adapted to store the cosmetic compositions (bottles, tube, spray bottle, aerosol bottle in particular).

Such a kit makes it possible to implement the method of treating the skin according to the invention.

The method according to the invention is particularly intended to smooth the wrinkled human skin of the face and / or the body, in particular to reduce or erase wrinkles and / or fine lines of the skin.

The tensor effect can be characterized by an in vitro retraction test as described in Examples 1 to 4. A polysaccharide grafted with (meth) acrylate groups is understood to mean a polysaccharide of which all or some free hydroxyl groups have been esterified to form (meth) acrylate ester groups. The graft polysaccharide used according to the invention may be chosen from hyaluronic acid, dextran and carrageenan grafted (meth) acrylate, such as those described below. Advantageously, the grafted polysaccharide (meth) acrylate has a weight average molecular weight ranging from 5,000 to 1,000,000 daltons, preferably ranging from 10,000 to 500,000 daltons, and even more preferably ranging from 15,000 to 350,000 daltons.

According to a first embodiment of the process according to the invention, the grafted polysaccharide may be a (meth) acrylate grafted hyaluronic acid. Hyaluronic acid is a linear glycosaminoglycan composed of repeating units of D-glucuronic acid and N-acetyl-D-glucosamine linked together by alternating beta-1,4 and beta-1,3 glycoside linkages. Preferably, the grafted hyaluronic acid polymer has a weight average molecular weight ranging from 5,000 to 1,000,000 daltons, more preferably ranging from 10,000 to 500,000 daltons, and even more preferentially ranging from 15,000 to 350,000 daltons. The molecular weight can be determined in particular by liquid phase chromatography, 0.1 M sodium chloride eluant and 330 mg / I sodium azide in water, dextran standard, VVYATT OPTILAB T-Rex refractometer detectors and light scattering. DAVVN-HELEOS II - VVYATT.

Advantageously, the grafted hyaluronic acid polymer has a degree of grafting in (meth) acrylate groups ranging from 10 to 80% or 20 to 80%, preferably ranging from 40 to 70%, and preferably ranging from 45 to 65%. The degree of grafting corresponds to the molar percentage of hydroxyl groups of hyaluronic acid which are grafted with a (meth) acrylate group. By way of example, a degree of grafting of 50% corresponds to 2 acrylate groups grafted onto the 4 hydroxyls of the repeating unit of hyaluronic acid. The grafting of hyaluronic acid by the (meth) acrylate groups results from the presence of ester (meth) acrylate group formed with the free hydroxyls of hyaluronic acid.

Preferably, the hyaluronic acid is grafted with acrylate groups. The hyaluronic acid grafted with (meth) acrylate groups can be obtained by reaction of hyaluronic acid with (meth) acrylic anhydride. The reaction is advantageously carried out in a basic aqueous medium, especially in the presence of an organic or inorganic base such as sodium hydroxide. Preferably, the reaction is conducted at a temperature ranging from 5 to 10 ° C, especially for a period ranging from 24 hours to 48 hours.

## STR1 ## Various levels of grafting with the (meth) acrylate groups can be obtained by varying the amount of (meth) acrylic anhydride used in proportion to the amount of hyaluronic acid. According to a second embodiment of the process according to the invention, the grafted polysaccharide may be a grafted dextran (meth) acrylate.

Dextran is a branched polysaccharide of d-glucose (dextrose) having a linear backbone whose glucoses are linked together by alpha 1-6 bonds; it has branched chains consisting of d-glucose linked together by alpha bonds 12 or 1-3 or 1-4.

Preferably, the grafted dextran polymer has a weight average molecular weight ranging from 10,000 to 1,000,000 daltons, more preferably ranging from 10,000 to 500,000 daltons, and even more preferably ranging from 15,000 to 350,000 daltons. The weight average molecular weight may in particular be determined by gel permeation liquid phase chromatography or by size exclusion chromatography. Advantageously, the grafted dextran polymer has a degree of grafting in (meth) acrylate groups ranging from 2 to 70%, preferably ranging from 3 to 65%, and preferentially ranging from 5 to 60%. The degree of grafting corresponds to the molar percentage of hydroxyl groups of dextran which are grafted with a (meth) acrylate group. By way of example, a grafting rate of 50% corresponds to 1.5 acrylate groups grafted onto the 3 hydroxyls of the repeating unit of dextran. The grafting of dextran by the (meth) acrylate groups results from the presence of ester group ( meth) acrylate formed with the free hydroxyls of dextran.

Preferably, the dextran is grafted with methacrylate groups. Dextran grafted with (meth) acrylate groups can be obtained by reaction of dextran with (meth) acrylic anhydride. The reaction is advantageously carried out in aprotic polar solvent medium (for example dimethylformamide, N-methylpyrrolidine, N-ethylpyrrolidine), especially in the presence of a non-nucleophilic organic or inorganic base, such as, for example, tertiary amines (such as triethanolamine). ). Preferably, the reaction is conducted at a temperature ranging from 20 to 100 ° C, especially for a period of from 1 to 12 hours. 31. Various levels of grafting with the (meth) acrylate groups can be obtained by varying the amount of (meth) acrylic anhydride employed in proportion to the amount of dextran, as well as the reaction conditions such as the temperature and the duration of the reaction. According to a third embodiment of the process according to the invention, the grafted polysaccharide may be a grafted carrageenan (meth) acrylate. Carrageenans are sulphated polysaccharides that form the cell walls of various red algae from which they can be obtained. Among these red algae include but are not limited to Kappaphycus alvarezii, Eucheuma denticulatum, Eucheuma spinosum, Chondrus crispus, Betaphycus gelatinum, Gigartina skottsbergii, Gigartina canaliculata, Sarcothalia crispata, Mazzaella laminaroides, Hypnea musciformis, Mastocarpus stellatus and Iridaea cordata.

They have long galactan chains, formed by disaccharide units. These polysaccharides are composed of alternating (1-> 3) pD-galactopyranose (unit G) and (1-> 4) a-galactopyranose (unit D) or 3,6-anhydro-a-galactopyranose (unit AnGal ). Each sugar unit may be sulphated one or more times at the 2, 3, 4 or 6 position. Methyl groups, pyruvic acid groups and also other sugar units grafted onto the basic structures described above may also be found. The carrageenans were initially subdivided according to their solubility in KCl, then according to the number, the position of the sulfate groups and the presence of 3 ', 6'-anhydro bridges on the galactopyranosyl residues. There are at least fifteen listed carrageenans whose structure depends on the original algae and the extraction method. Among the most common one may mention the carrageenans below: ## STR5 ## Carrageenan (1 - 3) 13-D-galactopyranose-4-sulphate (1 -> 4) - α-D-galactopyranose-6-sulphate Carrageenan (1-> 3) 13-D-galactopyranose-4-sulphate- (1-> 4) 3,6-anhydro-α-D-galactopyranose OH 2 SO 3 - Alkaline-Carrageenan (1 → 3) -D-galactopyrano-4-sulphate- (1 → 4) -oc-D-galactopyranose -2,6-disulfate-1-carrageenan (1->) 3) 13-D-galactopyranose-4-sulphate- (1-> 4) 3,6-anhydro-α-D-galactopyranose-2-sulphate O 30 OH 0s03 - Alkaline treatment - Os0, - HO Carrageenan (1 - > 3) -D-galactopyrano se-2-sulphate- (1 → 4) -oc-D-galactopyranose -2,6-disulfate O-carrageenan (1 → 3) 13-D-galactopyranose-2-sulphate (1) -> 4) 3,6-anhydro-oc-D-galactopyranose-2-sulphate These carrageenans are thus often obtained in the form of mixtures of different structures such as, and without limitation, mixtures of forms 143, the usable carrageenans may especially be selected from carrageenan type t, K, V, X, 0. Carrageenan particularly suitable for the implementation of the invention are carrageenan type t, v, X. It is preferably used lambda carrageenan . The carrageenans of the present invention can be used in acid form or in salified form. As acceptable salts include, but not limited to, the salts of lithium, sodium, potassium, calcium, zinc, ammonium. Preferably, the grafted carrageenan polymer has a weight average molecular weight ranging from 10,000 to 1,000,000 daltons, more preferably ranging from 10,000 to 500,000 daltons, and even more preferably ranging from 15,000 to 350,000 daltons.

The molecular weight can be determined in particular by liquid phase chromatography, 0.1 M sodium chloride eluant and 330 mg / I sodium azide in water, dextran standard, VVYATT OPTILAB T-Rex refractometer detectors and light scattering. DAVVN-HELEOS II - VVYATT.

Advantageously, the grafted carrageenan polymer has a degree of grafting in (meth) acrylate groups ranging from 2 to 60%, preferably ranging from 2 to 50%, and preferably ranging from 5 to 30%. The degree of grafting corresponds to the molar percentage of hydroxyl groups of carrageenan which are grafted with a (meth) acrylate group.

By way of example, a grafting rate of 50% corresponds to 1.5 acrylate groups grafted onto the 3 hydroxyls of the repeating unit of carrageenan. The grafting of carrageenan by the (meth) acrylate groups results from the presence of ester group ( meth) acrylate formed with the free hydroxyls of carrageenan. Preferably, the carrageenan is grafted with acrylate groups.

Carrageenan grafted with (meth) acrylate groups can be obtained by reacting carrageenan with (meth) acrylic anhydride. The reaction is advantageously carried out in a basic aqueous medium, especially in the presence of an organic or inorganic base such as sodium hydroxide. Preferably, the reaction is conducted at a temperature ranging from 5 to 10 ° C, especially for a period ranging from 24 hours to 48 hours. 8 -03S / R = H or COCH = CH2 Different levels of grafting with the (meth) acrylate groups can be obtained by varying the amount of (meth) acrylic anhydride used in proportion to the amount of carrageenan. Advantageously, a carrageenan chosen from p-carrageenan, À-carrageenan,--carrageenan and preferably À-carrageenan is used. The grafted polysaccharide polymer as defined above may be present in the composition used according to the invention (in particular composition A) in a content ranging from 0.1 to 10% by weight, relative to the total weight of the composition, preferably from 0.5% to 10% by weight of active material, and preferably from 1% to 8% by weight, and more preferably from 1% to 6% by weight. Advantageously, the grafted polysaccharide is chosen from acrylate grafted hyaluronic acid, methacrylate grafted dextran and acrylate grafted carrageenan. The crosslinking thiol used in the invention is a compound comprising one or more thiol groups (SH) and optionally another function capable of reacting with the ethylenic unsaturation of the (meth) acrylate groups grafted onto the polysaccharide, such as an amine function. primary or secondary, preferably primary amine. The crosslinking thiol may be a crosslinking polythiol or monothiol as described below. By polythiol compound is meant an all-carrier compound of two or more thiol groups SH. It may be a non-polymeric organic molecule carrying two or more thiol groups, or a polymer carrying two or more thiol groups. The polythiol compound according to the invention must not contain vinyl (C = C) (non-aromatic) or acetylenic (CEC) vinyl functional groups. The polythiol compound may be aromatic, or heteroaromatic, or contain an aromatic radical. The polythiol compound used according to the invention may also contain one or more heteroatoms chosen from O, N, S and / or one or more functions chosen from the ester, ketone, amide, urea and isocyanurate functions. Preferably, the compound The polythiol used according to the invention may furthermore contain one or more heteroatoms chosen from O, N, S and / or one or more functions chosen from among the ester and ketone functions. According to a first variant, the polythiol compound used according to the invention refers to a non-polymeric organic compound and can be represented by the formula (1) vv (S1-1) n (I) in which n denotes an integer greater than or equal to 2, preferably between 2 and 10, preferably between 2 and 5. and VV denotes a multivalent (at least divalent) radical 02-080 linear or branched or (hetero) cyclic, saturated, an aromatic radical, a heteroaromatic cyclic radical, VV may also contain one or more heteroatoms such as O, N, S, and / or one or more functions chosen from esters, ketones, amides, ureas, preferably esters, ketones) and / or be substituted by one or more linear C1-010 alkyl groups. or branched, hydroxyl, amino, linear or branched C1-010 (C1-C6 alkyl) amino, carboxylic acid, carboxylate, C1-C10 alkoxy, it being understood that when the radical VV is substituted, the thiol functions can be borne by the substituent (s) ).

By cyclic radical is meant a saturated monocyclic radical, hydrocarbon or heterocyclic, a saturated or aromatic polycyclic radical for example biphenyl or condensed rings such as for example the naphthyl radical.

The molar mass of the compounds of formula (1) is generally between 70 and 1500 g / mol and preferably between 70 and 500 g / mol. According to a first embodiment, the polythiol compound of formula (1) is such that n = 2 (dithiol) and VV denotes a linear or branched, divalent saturated hydrocarbon radical O 2 - O 2 O, preferably O 2 - O 12. According to this embodiment, the polythiol compound of the invention denotes, for example, 1,2-ethanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, 1,6 hexanedithiol, 1,7-heptanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, 1,10-decanedithiol, 1,12-dodecanedithiol, 2,2-dimethyl-1,3-propanedithiol, 3-Methyl-1,5-pentanedithiol, 2-methyl-1,8-octanedithiol, According to a second embodiment, the thiol-containing compound of formula (1) is such that n = 3 and VV denotes a radical. saturated linear hydrocarbon saturated 03-020 linear or branched, preferably 02-012 linear or branched.

According to this embodiment, the thiol unit compound may be chosen for example from 1,1,1-tris (mercaptomethyl) ethane, 2-ethyl-2-mercaptomethyl-1,3-propanedithiol, 1,2, 3-propanetrithiol. According to a third embodiment, the thiol unit compound of formula (1) is such that n = 2 or 3 and VV denotes a linear or branched, divalent or trivalent saturated hydrocarbon radical 03-020, preferably linear or branched 02-012 said radical containing one or more non-adjacent heteroatom (s) selected from O, S. According to this embodiment, the thiol-patterned compound may be chosen for example from bis-2-mercaptoalkyl ethers and sulfides, such as bis (2-mercaptoethyl) ether, bis (2-mercaptoethyl) sulfide, bis- (2-mercaptoethylthio-3-mercaptopropane) sulfide o alkanes (C 1 -C 5) bis (2-mercapto alkyl (C 1 -C 3) thio) or mercaptoalkanes (C 1 -C 5) bis (2-mercapto alkyl (C 1 -C 3) thio) such as, for example, bis (2-mercaptoethylthio) methane, 1,2-bis (2-mercaptoethylthio) ethane, 1,3-bis (2-mercaptoethylthio) ethane, bis (2-mercaptoethylthio) propane, 1,2-bis (2-mercaptoethylthio) propanethiol, 1,2-bis (2-mercaptoethyl) thio-3-mercaptopropane, 1,2,3-tris (2-mercapto) ethyl thio) propane Preferably, according to this embodiment, the compound (1) is chosen from 1,2-bis (2-mercaptoethylthio) propanethiol, 1,2,3-tris (2-mercaptoethylthio) propane, Tetrakis (2-mercaptoethylthiomethyl) methane. According to a fourth embodiment, the thiol unit compound of formula (1) is such that n denotes an integer greater than or equal to 2 and VV denotes a linear or branched saturated hydrocarbon saturated (at least divalent) radical 03-020 of preferably linear or branched 02-012, said radical containing at least one ester function. According to this embodiment, the thiol unit compound may be chosen, for example, from polyol esters (glycols, triols, tetraols, pentaols, hexaols) and from C1-C6 mercaptocarboxylic acid such as ethylene glycol bis (2). mercaptoacetate), ethylene glycol bis (3-mercaptopropionate), ethylene glycol bis (thioglycolate), trimethylolpropane tris (thioglycolate), trimethylolpropane tris (beta-mercaptopropionate), pentaerythritol tetrakis (thioglycolate), pentaerythritol tetrakis (. beta.-mercaptopropionate), dipentaerylthritol hexakis (.beta.-mercaptoproprionate), trimethylolpropane tris (2-mercaptoacetate), trimethylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (2-mercaptoacetate), pentaerythritol tetrakis (3mercaptopropionate) , pentaerythritol tetrakis (3-mercaptobutanate), dipentaerythritol hex-3-mercaptopropionate, Preferably, according to this embodiment, the thiol-patterned compound is chosen from tri methylolpro pane tris (2-mercaptoacetate), tri-methylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (2-mercaptoacetate), pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptobutanate), dipentaerythritol hex-3 -mercaptopropionate. Particularly preferably, the thiol-patterned compound is pentaerythritol tetrakis (3-mercaptopropionate).

According to a fifth embodiment, the thiol unit compound of formula (I) is such that n = 4 and VV denotes a saturated hydrocarbon radical saturated with 0-020, preferably branched 08-014 interrupted by one or more sulfur atoms According to this embodiment, the thiol unit compound may be chosen, for example, from tetrakis (2-mercaptoethylthiomethyl) methane, bis (2-mercaptoethylthio-3-mercaptopropane) sulfide. According to a sixth embodiment, the thiol unit compound of formula (I) is such that n = 2 and VV denotes a cyclic divalent hydrocarbon radical optionally containing one or more non-adjacent sulfur atoms, optionally substituted by one or more alkyl radicals. C1-010 linear or branched. According to this embodiment, the thiol unit compound may be chosen for example from 1,4-cyclohexane dithiol, 1,4-bis (mercaptomethyl) cyclohexane, 1,1-cyclohexane dithiol, 1,2-cyclohexane dithiol, 1,1-bis (mercaptomethyl) cyclohexane, 2,5-dimercapto-1,4-dithiane. According to a seventh embodiment, the thiol unit compound of formula (I) is such that n = 3 and VV denotes a cyclic radical of substituted isocyanurate type.

According to this embodiment, the thiol unit compound may be chosen for example from the polythiols of the isocyanurate class described in US Pat. Nos. 3,676,440 and US20110230585, such as tris ((mercaptopropionyloxy) ethyl) isocyanurate. According to this embodiment, the thiol-patterned compound refers to tris ((mercaptopropionyloxy) -ethyl) isocyanurate.

According to an eighth embodiment, the thiol unit compound of formula (I) is such that n = 2 or 3 or 4 and VV denotes an aromatic radical optionally substituted with one or more identical or different radicals of C1-010 alkyl type, C1-C10 alkoxy, it being understood that when the radical VV is substituted, the thiol functions can be borne by the substituent (s). According to this embodiment, the thiol unit compound may be chosen, for example, from 1,2-dimercaptobenzene, 1,3-dimercaptobenzene, 1,4-dimercaptobenzene, 1,2-bis (mercaptomethyl) benzene, , 3-bis (mercaptomethyl) benzene, 1,4-bis (mercaptomethyl) benzene, 1,2-bis (2-mercaptoethyl) benzene, 1,3-bis (2-mercaptoethyl) benzene, 1,4 bis (2-mercaptoethyl) benzene, 1,2-bis (2-mercaptoethyleneoxy) benzene, 1,3-bis (2-mercaptoethyleneoxy) benzene, 1,4-bis (2-mercaptoethyleneoxy) benzene, , 2,3-trimercaptobenzene, 1,2,4-trimercaptobenzene, 1,3,5-trimercaptobenzene, 1,2,3-tris (mercaptomethyl) benzene, 1,2,4-tris (mercaptomethyl) benzene 1,3,5-tris (mercaptomethyl) benzene, 1,2,3-tris (2-mercaptoethyl) benzene, 1,2,4-tris (2-mercaptoethyl) benzene, 1,3,5-tris tris (2-mercaptoethyl) benzene, 1,2,3-tris (2-mercaptoethyleneoxy) benzene, 1,2,4-tris (2-mercaptoethyleneoxy) benzene, 1,3,5-tris (2- mercaptoethyleneoxy) benzene, 1,2,3,4-tetramercaptobenzene, 1 2,3,5-tetramercaptobenzene, 1,2,4,5-tetramercaptobenzene, 1,2,3,4-tetrakis (mercaptomethyl) benzene, 1,2,3,5-tetrakis (mercaptomethyl) benzene, 1,2,4,5-tetrakis (mercaptomethyl) benzene, 1,2,3,4-tetrakis (2-mercaptoethyl) benzene, 1,2,3,5-tetrakis (2-mercaptoethyl) benzene, 1,2,4,5-tetrakis (2-mercaptoethyl) benzene, 1,2,3,4-tetrakis (2-mercaptoethyleneoxy) benzene, 1,2,3,5-tetrakis (2-mercaptoethyleneoxy) benzene, 1,2,4,5-tetrakis (2-mercaptoethyleneoxy) benzene, 2,2'-dimercaptobiphenyl, 4,4'-dimercaptobiphenyl, 4,4'-dimercaptobibenzyl, 2,5-toluenedithiol, 3 , 4-toluenedithiol, 1,4-naphthalenedithiol, 1,5-naphthalenedithiol, 2,6-naphthalenedithiol, 2,7-naphthalenedithiol, 2,4-dimethylbenzene-1,3-dithiol, 4,5 1,3-bis (2-mercaptoethylthio) benzene, 1,4-bis (2-mercaptoethylthio) benzene, 1,2-bis (2-dimethylbenzene-1,3-dithiol, 9,10-anthracenedimethanethiol, 1,3-bis (2-mercaptoethylthio) benzene) -mercaptoethylthiomethyl) benzene, 1,3-bis (2-mercaptoethylthiomethyl) benzene, 1,4-bis (2-mercaptoethylthiomethyl) benzene, 1,2,3-tris (2-mercaptoethylthio) benzene, 1,2,4-tris (2-mercaptoethylthio) benzene, 1,3,5-tris (2-mercaptoethylthio) benzene, 1,2,3,4-tetrakis (2-mercaptoethylthio) benzene, 1,2,3,5-tetrakis (2-mercaptoethylthio) benzene, 1,2,4,5- Tetrakis (2-mercaptoethylthio) benzene, 3,4-thiophenedithiol. According to this embodiment, the compound (I) is chosen from 1,2,3-trimercaptobenzene, 1,2,4-trimercaptobenzene, 1,3,5-trimercaptobenzene, 1,2,3-tris ( mercaptomethyl) benzene, 1,2,4-tris (mercaptomethyl) benzene, 1,3,5-tris (mercaptomethyl) benzene, 1,2,3-tris (2-mercaptoethyl) benzene, 1,2, 4-tris (2-mercaptoethyl) benzene, 1,3,5-tris (2-mercaptoethyl) benzene, 1,2,3-tris (2-mercaptoethyleneoxy) benzene, 1,2,4-tris (2-mercaptoethyl) benzene, -mercaptoethyleneoxy) benzene, 1,3,5-tris (2-mercaptoethyleneoxy) benzene, 1,2,3,4-tetramercaptobenzene, 1,2,3,5-tetramercaptobenzene, 1,2,4,5 tetramercaptobenzene, 1,2,3,4-tetrakis (mercaptomethyl) benzene, 1,2,3,5-tetrakis (mercaptomethyl) benzene, 1,2,4,5-tetrakis (mercaptomethyl) benzene, 2,3,4-tetrakis (2-mercaptoethyl) benzene, 1,2,3,5-tetrakis (2-mercaptoethyl) benzene, 1,2,4,5-tetrakis (2-mercaptoethyl) benzene, 1,2,3,4-tetrakis (2-mercaptoethyleneoxy) benzene, 1,2,3,5-tetrakis (2-mercaptoethyleneoxy) benzene 1,2,4,5-tetrakis (2-mercaptoethyleneoxy) benzene, 1,2,3-tris (2-mercaptoethylthio) benzene, 1,2,4-tris (2-mercaptoethylthio) benzene, , 3,5-tris (2-mercaptoethylthio) benzene, 1,2,3,4-tetrakis (2-mercaptoethylthio) benzene, 1,2,3,5-tetrakis (2-mercaptoethylthio) benzene, 1, 2,4,5-Tetrakis (2-mercaptoethylthio) benzene, 3,4-thiophenedithiol. According to a ninth embodiment, the thiol unit compound of formula (I) is such that n = 2 or 3 or 4 and VV denotes a fatty acid triglyceride or an optionally substituted vegetable oil, it being understood that when the radical VV is substituted, the thiol functions can be carried by the substituent (s). According to this embodiment, the thiol unit compound may be chosen for example from: triglycerides of fatty acids or vegetable oils modified with thiol groups by chemical reaction, for example thiolated soybean oils and soybean oils and thiolated products in particular polymercaptan® products from Chevron Phillips such as polymercaptan 358 (mercaptanized soybean oil) and polymercaptan 407 (mercapto hydroxy soybean oil), IL (cH2) 17cH3 sH According to a tenth embodiment, the thiol-patterned compound of formula (I) is such that n = 2 and VV denotes a C2-C6 saturated divalent hydrocarbon radical, substituted with one or more hydroxyl groups. According to this embodiment, the thiol unit compound may be chosen for example from dithiothreitol, 2,3-dimercapto-1-propanol. According to an eleventh embodiment, the thiol unit compound of formula (I) is such that n = 2 and VV denotes a C2-C6 saturated hydrocarbon divalent radical substituted by one or more carboxylic acid or carboxylate group (ester group in C2-05). According to this embodiment, the thiol unit compound of formula (I) may be meso-2,3-dimercaptosuccinic acid and its C 1 -C 4 alcohol esters.

According to this first variant, the compounds of formula (I) for which n denotes an integer ranging from 2 to 4 are preferred. Preferably, according to this variant, the compounds of formula (I) are chosen from the compounds of the fourth embodiment. ; especially tris (2-mercaptoacetate) triethylolpropane, trimethylol propane tris (3-mercaptopropionate), pentaerythritol tetrakis (2-mercaptoacetate), pentaerythritol O -O-LL (CH2) 70 (CH2), CH3 HS ## STR2 ## Polymercaptan 358 tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptobutanate), dipentaerythritol hex-3-mercaptopropionate, and more particularly pentaerythritol Tetrakis (3-mercaptopropionate); or among the compounds of the tenth embodiment, such as, in particular, dithiothreitol.

Particularly preferably, according to this variant, the compounds of formula (I) denote pentaerythritol tetrakis (3-mercaptopropionate), dithiothreitol. According to a second variant, the polythiol compound used according to the invention denotes a polymeric compound and may be represented by the formula (II) POL (SH) n (II) in which n denotes an integer greater than or equal to 5, preferably between 5 and 5000, preferably between 5 and 1000. and POL denotes a multivalent polymeric radical (at least pentavalent) carbon or silicone, POL may further contain one or more heteroatoms such as 0, N, S, and / or one or more functions chosen from the ester, ketone, amide, urea and carbamate functions, and / or be substituted by one or more linear or branched C1-010 linear or branched C1-010 alkyl groups, it being understood that when POL is substituted, thiol functions can be carried by the substituent (s). The molar mass of the compounds of formula (II) is generally between 500 and 400000 g / mol, preferably between 500 and 150 000 g / mol.

POL may denote a multivalent radical of the homopolymer or copolymer type; POL may denote a polymeric radical of the star, comb, brush or dendritic radical type. The POL radical may be of natural origin (such as polysaccharides, peptides) or synthetic (such as acrylic polymers, polyesters, polyglycols).

The thiol functions (-SH) may be terminal and / or pendant groups. According to a first embodiment, the thiolated compound of formula (II) is such that POL denotes a polymeric hydrocarbon radical. Examples of these are the polymers described in the following articles: Polymers containing groups of biological activity, CG Overberger et al., Polytechnic Institute of Brooklyn, http://pac.iupac.org/publications/pac/pdf/1962/pdf/ 0402x0521.pdf and Mercaptan-containing Polymers, Advances in Polvmer Science Volume 15, 1974, pp 6190.

In particular, mention may be made of thiol-containing compounds of formula (II) such as poly (vinylmercaptan), poly (4-mercaptostyrene), poly (vinylbenzylmercaptan), poly (4-mercaptostyrene) -co-poly (methylmethacrylate), and also polymers containing the amide functions in the polymer such as poly (hexamethylene adipamide thiolated). The compounds of formula (II) also denote proteins and peptides with thiol units, for example the structures represented in the following table: ## STR1 ## CH 2 CH 3 CH 3 CH 3 CH 2 COOH 0 0 0. ## STR2 ## wherein CH 2 -C (CH 2) n -CH (CH 2) 2 -CH-C-NH- (CH 2) O -NH- (CH 2) 2 -NH- (CH 2) 4 CI 1 I to ## STR5 ## ## STR2 ## ## STR2 ## ## STR2 ## ## STR2 ## The thiolated compound of formula (II) also denotes the compounds of formula (II) such as: ## STR2 ## ## STR4 ## that POL denotes a so-called dendrimer radical, branched or hyperbranched polymer and the thiol groups are terminal. Examples that may be mentioned include the polymers described in Progress in Organic Coatings, Volume 63, Issue 1, July 2008, Pages 100-109. As an example of synthesis of such polymers include the synthesis described in this article where the Boltorn H40 polymer is converted into thiolated polymer of formula (II) according to the scheme below: HI 6 is given below: The thiol unit compound of formula (II) can also denote a hyperbranched or dendritic polymer modified with thiol functions as described in application FR 2761691. F, S Polypropylene ether bis glycol polymers (beta.-mercaptopropionate) are also usable. They are prepared from polypropylene ether glycol (e.g., Pluracol P201, Wyandotte Chemical Corp.) and beta-mercaptopropionic acid by esterification reaction and known to those skilled in the art. Certain thiol-patterned polymers of formula (II) are also commercially available such as THIOCURE® products from Bruno Brock, THIOCURE® ETTMP 1300 (Ethoxylated-Trimethylolpropan Tri-3-Mercaptopropionate (CAS # 34535219-4) and THIOCURE ETTMP 700 (Ethoxylated trimethylolpropan tri-3-mercaptopropionate (CAS # 345352-19-4); In a second embodiment, the compound of formula (II) is such that POL denotes a silicone polymeric radical. mention may be made of polythiol silicones. Polythiol silicones are in particular polydimethylsiloxane comprising two or more thiol groups such as, for example, the products SMS-022, SMS 042 and SMS 992 sold by the company Gelest Inc. SM CH. (.1 Si-Si / CH3 CH3 The crosslinking thiol may also be a monothiol comprising another function capable of reacting with the ethylenic unsaturation of the (meth) acrylate groups grafted onto the polysaccharide, such as a primary or secondary amine function, preferably a primary amine. The crosslinking thiol may in particular be an aminothiol, in particular a compound of formula (III): HS) -L- (NHR) b (III) in which b denotes an integer ranging from 1 to 5, preferably ranging from 1 to 3 , and more preferably equal to 1; L denotes a linear or branched (saturated) or saturated (hetero) cyclic (at least divalent) radical 02-080, an aromatic radical, a heteroaromatic cyclic radical, VV may also contain one or more non-adjacent heteroatoms such as O, N, S, and / or one or more functional groups selected from esters, ketones, amides, ureas, carbamates, preferably esters, ketones) and / or be substituted by one or more linear or branched C 1 -C 10 alkyl, hydroxyl or carboxylic groups. linear or branched C 1 -C 20 alkoxycarboxylate, carboxylate, it being understood that when the radical VV is substituted, the thiol functions may be borne by the substituent (s); R denotes a hydrogen atom or a C1-C6 alkyl radical, or CH300- or C2H5-CO-, and preferably a hydrogen atom. Aminothiol compounds that may be mentioned include cysteamine, N-acetylcysteamine, cysteine, N-acetylcysteine, homocysteine, compounds of formula HS- (CH2) n-NH- (CH2) m -NH2, n and m being integers from 1 to 4, ortho-aminothiophenol, meta-aminothiophenol, para-aminothiophenol. Preferably, the crosslinking thiol is chosen from: cysteamine, dithiothreitol, pentaerhytritol tetra (3-mercaptopropionate). Preferably, the crosslinking thiol is cysteamine.

Preferably, the process according to the invention is carried out with hyaluronic acid grafted with acrylate groups and cysteamine. Advantageously, the composition (in particular composition B) comprising the crosslinking thiol used in the process according to the invention is an aqueous composition having a pH ranging from 5 to 10.5, preferably ranging from 6 to 9, and preferably ranging from from 7 to 8.5. According to one embodiment of the process according to the invention, an extemporaneous mixture of the grafted polysaccharide polymer is carried out with (meth) acrylate groups and a crosslinking thiol compound and the mixture is applied to the skin. Sequential application to the skin can also be carried out on the one hand of the saccharide polymer grafted with (meth) acrylate groups and on the other hand with the crosslinking thiol compound.

Advantageously, the thiol compound used in the process according to the invention is used according to a molar ratio thiol compound / (meth) acrylate group of the graft polysaccharide ranging from 0.01 to 10, preferably ranging from 0.01 to 5. The thiol compound may be present in the composition B used according to the invention in a content ranging from 0.1 to 100% by weight, relative to the total weight of the composition, and preferably ranging from 1 to 10% by weight. The crosslinked thiol compound in contact with the grafted polysaccharide of (meth) acrylate groups reacts with the ethylenic unsaturations of the (meth) acrylate groups grafted onto the polysaccharide to form thio bonds with the terminal carbon of the ethylenic unsaturation of the (meth) group. acrylate (this reaction is known as Michael's reaction).

Examples of this reaction are illustrated with dextran (meth) acrylate in the following schemes: ## STR2 ## When the grafted dextran comprises methacrylate groups, a catalyst can be used in the presence of the thiol compound. This catalyst makes it possible to obtain a good reactivity of the thiol compound on the ethylenic unsaturation of the methacrylate group. The catalyst may be chosen from the catalysts described in the articles "Tetrahedron Letters 48 (2007) pages 141-143" and "Tetrahedron Letters 46 (2005) pages 8329-8331" as well as the articles cited in these two articles. Examples of catalysts that may be mentioned are Lewis acids such as boric acid, aluminum chloride or cerium chloride, as well as phosphines such as trimethylphosphine (trialkylphosphine), phenyldimethylphosphine (dialkylarylphosphine), diphenylmethylphosphine (alkyldiarylphosphine) triphenylphosphine (triarylphosphine), tricarboxyethylphosphine, and oxide equivalents. The compositions used according to the invention are generally suitable for topical application to the skin and therefore generally comprise a physiologically acceptable medium, that is to say a medium that is compatible with the skin and / or or its integuments. It is preferably a cosmetically acceptable medium, that is to say which has a pleasant color, odor and feel and that does not generate unacceptable discomfort (tingling, tightness, redness), likely to divert the consumer from using this composition. The compositions according to the invention may be in any of the galenical forms conventionally used for topical application and especially in the form of dispersions of the lotion or aqueous gel type, emulsions of liquid or semi-liquid consistency of the milk type, obtained by dispersion. a fatty phase in an aqueous phase (O / W) or conversely (W / O), or suspensions or emulsions of soft, semi-solid or solid consistency of the cream or gel type, or multiple emulsions (E / H / E or H / E / H), microemulsions, vesicular dispersions of ionic and / or nonionic type, or wax / aqueous phase dispersions. These compositions are prepared according to the usual methods. According to a preferred embodiment of the invention, the compositions are in the form of an O / W emulsion or an aqueous gel. Advantageously, the compositions used according to the invention comprise water, in particular in a content ranging from 10 to 99% by weight, relative to the total weight of the composition, and preferably ranging from 50 to 99% by weight. The compositions used according to the invention may also contain one or more adjuvants commonly used in the cosmetics field, such as emulsifiers, preservatives, sequestering agents, perfumes, thickeners, oils, waxes and film-forming polymers. Of course, those skilled in the art will take care to choose this or these optional additional compounds and / or their amount so that the properties of the composition according to the invention are not, or not substantially impaired by the addition envisaged. According to a first embodiment of the process according to the invention, an extemporaneous mixture of a composition, in particular a cosmetic composition, comprising the grafted polysaccharide (meth) acrylate polymer and a crosslinking thiol compound as described above is applied to the skin. . The extemporaneous mixture is advantageously carried out less than 5 minutes before its application to the skin, and preferably less than 3 minutes. According to a second embodiment of the process according to the invention, the composition, in particular the cosmetic composition, comprising the grafted (meth) acrylate polysaccharide polymer, is first applied to the skin, and then the crosslinking thiol compound or a cosmetic composition is applied thereto. container. The application of the crosslinking thiol compound can be carried out after a time of between 5 minutes and one hour after having applied the grafted polysaccharide polymer. The application of the cosmetic composition used according to the invention is carried out according to the usual techniques, for example by application (in particular of creams, gels, serums, lotions) to the skin to be treated, in particular the skin of the skin. face and / or neck, especially the skin around the eye. As part of this process, the composition may be, for example, a care composition. The invention will now be described with reference to the following examples given for illustrative and non-limiting. Synthesis Example 1 (polymer 1): Hyaluronic acid functionalized to 60% with acrylic anhydride In a thermostated reactor, 5 g of hyaluronic acid (Hyacare® 50 from Evonik) were dissolved in 100 ml of water and the mixture was maintained at a temperature of 7 ° C. then 14.8 g of acrylic anhydride was added dropwise for about 2 minutes. the pH was adjusted to 7.7 by slow addition (for about one hour) of 30% sodium hydroxide in water (7 M). It was allowed to react for 24 hours. The mixture obtained was purified by dialysis (polymer in 150 ml of water, 3.3% by mass) on Spectra / Por® membrane 15 kDa for 5 days in 5 liters of water (water changed 4 times, ie 20 liters in total ), then the mixture of the purified fraction was lyophilized by freezing with a dry ice + acetone bath at -80 ° C and then placing the frozen mixture in a lyophilization apparatus for 4 days. 2.5 g of a white solid were obtained. Analyzes: 1H NMR D 2 O: 2.45 (7.36 / 3) functionalized OH units for 4 available OH units.

The hyaluronic acid obtained is functionalized to 60% by acrylate groups. Synthesis example 2 (polymer 2): Dextran functionalized with 33% of methacrylate groups 10 g of dextran (sold under the reference 406261000 by ACROS) were suspended in 40 ml of a mixture of lithium chloride / dimethylformamide ( to 10% by weight of LiCl) and the suspension was heated to 100 ° C. 20 ml of the lithium chloride / dimethylformamide mixture were added until complete dissolution of the dextran. The mixture was then cooled to 80 ° C and then 0.56 g of triethanolamine was added, stirred for 15 minutes at 80 ° C and then 8.55 g of methacrylic anhydride added by slow addition (10 minutes). It was left stirring for 5 hours at 70 ° C and then allowed to warm to room temperature (25 ° C). The reaction mixture was then poured into 150 ml of isopropanol, stirred for 1 hour and then filtered. 11.8 g of a white solid were obtained. Analyzes: 1H NMR D20: 1 OH functionalized unit for 3 OH units available.

The dextran obtained is functionalized at 33% by acrylate groups. Synthesis Example 3 (Polymer 3): Dextran Functionalized to 50% of Methacrylate Groups 10 g of dextran (sold under the reference 406261000 by ACROS) were suspended in 40 ml of a mixture of lithium chloride / dimethylformamide ( to 10% by weight of LiCl) and the suspension was heated to 100 ° C. 20 ml of the lithium chloride / dimethylformamide mixture were added until complete dissolution of the dextran. The mixture was then cooled to 80 ° C and then 0.56 g of triethanolamine was added, stirred for 15 minutes at 80 ° C and then 8.55 g of methacrylic anhydride added by slow addition (10 minutes). It was left stirring for 5 hours at 80 ° C and then allowed to warm to room temperature (25 ° C). The reaction mixture was then poured into 150 ml of isopropanol, stirred for 1 hour and then filtered. 13.4 g of a white solid were obtained.

Analyzes: 1H NMR D20: 1.5 OH functionalized units for 3 available OH units. The dextran obtained is functionalized at 50% with methacrylate groups.

Synthesis Example 4 (polymer 4): Carrageenan functionalized to 15% with acrylic anhydride In a thermostated reactor, 5 g of carrageenan (lambda form) (Satiagum UTC 10 from Cargill) were dissolved in 100 ml of water and the mixture was maintained at a temperature of 7 ° C. then 10.7 g of acrylic anhydride was added dropwise for about 2 minutes. the pH was adjusted to 7.7 by slow addition (for about one hour) of 30% sodium hydroxide in water (7 M). It was allowed to react for 24 hours. The mixture obtained was purified by dialysis (polymer in 150 ml of water, 3.3% by mass) on Spectra / Por® membrane 15 kDa for 5 days in 5 liters of water (water changed 4 times, ie 20 liters in total ), then the mixture of the purified fraction was lyophilized by freezing with a dry ice + acetone bath at -80 ° C and then placing the frozen mixture in a lyophilization apparatus for 4 days. 3.7 g of a white solid were obtained. Analyzes: 1H NMR D 2 O: 0.44 functionalized OH units for 3 available OH units. The carrageenan obtained is functionalized at 10% with acrylate groups.

Examples 1 to 4: Demonstration of the tensing effect of polymer blends with a thiol The tensor effect of the polymer of Example 1 was evaluated by an in vitro shrinkage test.

This test consists in comparing in vitro the tensor strength of the polymer and thiol mixture to be evaluated with respect to a standard tensor polymer: Hybridur® 875 polymer dispersion from Air Products (aqueous dispersion at 40% by weight of particles of a interpenetrating network of polyurethane and acrylic polymers).

The mixture of polymer and thiol to be evaluated was deposited on a strip of nitrile rubber cut in a glove sold under the reference "Safeskin Nitrile Criticial" No. 038846 by the company Dominique Dutscher SA, with a surface area of 3.5 cm 2 previously stretched on a support. The polymer and thiol mixture was deposited on the elastomeric strip by depositing 1.8 mg (dry matter) of polymer.

26 μl of an aqueous solution containing 7% MA of Hybridur® 875 polymer are thus deposited on a strip of nitrile rubber to thereby obtain a tensor reference strip. On another strip was deposited 104 μl of the mixture containing 1.75% MA hyaluronic acid acrylate and thiol. After drying for 24 hours (overnight) at room temperature (25 ° C), bending (retraction) of the strip treated with the mixture was observed in comparison with that obtained with the control (Hybridur® 875). A 1% by weight aqueous solution of cysteamine was prepared. The solution of hyaluronic acid acrylate (3.50% MA) and the cysteamine solution were then mixed in the proportions indicated in the table below and then a quantity of the mixture prepared was deposited on the nitrile rubber strips. . With the polymer of Example 1: Example Proportion of cysteamine (molar equivalent) with respect to the quantity of cysteamine solution (pL) Quantity of volume of the hyaluronic acid mixture mixture with acrylate groups sample for acrylate of the ex strip 1 (pL) 1 51 104 75 lb 0.5 40 104 63 1 c 0.4 10 104 67 ld 0.1 5 104 64 The tensor effect obtained according to the previously described protocol was measured. Then, the water resistance of the tensor effect was evaluated by dipping the treated rubber strips with the polymer to be evaluated in water at room temperature (25 ° C.) for 10 minutes. Mixture tested Tensor effect Tensor effect after immersion in water Hybridure number 875 correct correct Example 1 greater than the reference Less than the reference Example the comparable to the reference greater than the reference Example lb Comparable to the reference greater than the reference Example lc Comparable to the reference superior to the reference Example 1 d Comparable to the reference superior to the reference The results obtained show that mixtures of hyaluronic acid and cysteamine (ex la, 1b, 1c, 1d) make it possible to obtain a good residual tensor effect with water. Example 5 Demonstration of the tensing effect of polymer and thiol blends The tensing effect of the polymer of Example 3 mixed with a thiol was evaluated by an in vitro shrinkage test. This test consists of comparing in vitro the tensor strength of the polymer + thiol mixture to be evaluated with respect to a standard tensor polymer: Hybridur® 875 polymer dispersion from Air Products (aqueous dispersion at 40% by weight of particles of a network interpenetrating polyurethane and acrylic polymers). The polymer to be evaluated was deposited on a strip of nitrile rubber cut in a glove sold under the reference "Safeskin Nitrile Criticial" No. 038846 by the company Dominique Dutscher SA, with a surface of 3.5 cm 2 previously stretched on a support . Thus, an aqueous solution containing 7% MA of Hybridur® 875 polymer was deposited on a strip of nitrile rubber to thereby obtain a tensor reference strip.

On another strip was deposited a mixture containing the polymer and the thiol according to the amounts described in the table below.

After drying overnight (12 hours) at room temperature (22 ° C / 45% relative humidity), bending (shrinking) of the polymer-treated strip was observed in comparison with that obtained with the control (Hybridur® 875). The persistence of the tensor effect (i.e., the retention of the tensor effect upon transpiration or washing) was evaluated by rinsing the nitrile strips with an aqueous solution of 0.9M NaCl (10mL of the saline solution are projected onto the strip at a distance of 5 cm using a pipette). It was allowed to dry for 3 hours and the tensor effect (bending (retraction) of the strip) was again observed by comparing it to the effect obtained before rinsing.

The following solutions were prepared and applied (26 μl of the final solution) immediately onto the strips. Example Thiol polymer referenced aqueous solution of - 7% Hybridur 875 2 solution of the polymer of Example 3 at 5% m.a. in water - 2a 100 μl of a solution 50 μl of a solution of 5% dithiothreitol polymer in water Example 3 at 5% m.a. in the water The following results were obtained: Example Tensor effect before retentivity test Tensor effect after reference persistence test Lower Correct 2 Same as lower reference 2a Same as reference No change The result obtained with dextran grafted methacrylate Example 2 without thiol (Example 2) shows that it has a good tensor effect but the latter is not water-resistant. On the other hand, with treatment with a thiol such as dithiothreitol (Example 2a), the tensor effect of the polymer after rinsing shows no change with respect to the tensioning effect before rinsing. Treatment with the thiol compound thus makes it possible to obtain a remanent tensor effect. Examples 6 to 13: 30 Demonstration of the tensor effect in base coat application with polymer and in top coat with thiol application The tensor effect of the polymers of Examples 1 to 4 was evaluated according to the in vitro shrinkage test described in the previous example with the same reference of tensor polymer. On an elastomer strip, an aqueous solution of the polymer to be evaluated was deposited in the amount indicated in the table below. Then waited 5 minutes to then apply the aqueous solution containing the thiol.

The following applications were carried out: Example "Basecoat" with the "Topcoat" polymer with the thiol referenced 50 ml of an aqueous solution of Hybridur 875 at 7% by weight of 150 μl of a solution of the polymer P1 at 3% m.a. in water Nothing to 50 μl of a solution of the polymer P1 at 3% m.a. in water 10 μl of a solution of 5% dithiothreitol in water (pH 8 adjusted with ammonia) 1 b '50 μl of a solution of the polymer P1 at 3% m.a. in water 10 μl of a solution of pentaerythritol tetra (3-mercaptopropionate) at 10 μl in DMSO / ammonia 28 μl / 0 (99/1 v / v) 2 50 μl of a solution of the polymer P2 at 2.5% my in water nothing 2a '50 pl of a solution of the polymer P2 at 2.5% m.a. in water 10 μl of a solution of 5% dithiothreitol in water (pH 8 adjusted with ammonia) 2b 50 μl of a solution of polymer P2 at 2.5% m.a. in water 10 μl of a 10% pentaerythritol tetra (3-mercaptopropionate) solution in DMSO / 28% ammonia (99/1 v / v) 3 50 μl of a P3 polymer solution at 2.5% my in the water nothing is more than 50 μl of a solution of the 2.5% polymer m.a. in water 10 μl of a solution of 5% dithiothreitol in water (pH 8 adjusted with ammonia) 3b 50 μl of a 2.5% solution of polymer P3 m.a. in water 10 μl of a solution of pentaerythritol tetra (3-mercaptopropionate) at 10 ° C. in DMSO / ammonia 28 μl / 0 (99/1 v / v) 4 50 μl of a solution of the polymer P4 at 3% ma in water Nothing 4a 50 μl of a solution of the polymer P4 at 3% m.a. in water 10 μl of a solution of 5% dithiothreitol in water (pH 8 adjusted with ammonia) 4b 50 μl of a solution of the polymer P4 at 5% m.a. in water 10 μl of a solution of pentaerythritol tetra (3-mercaptopropionate) at 10 ° C / 0 in DMSO / ammonia 28 °) / 0 (99/1 v / v) The following results were obtained: Example tensor effect before test of remanence Tensor effect after retesting test reference Correct lower 1 Idem to the lower reference the 'Idem to the reference No change 1 b' Idem to the reference No change 2 Idem to the lower reference 2a 'Idem to the reference No change 2b 'Same as reference No change 3 Same as lower reference 3a' Same as reference No change 3b 'Same as reference No change 4 Same as lower reference 4a' Same as reference No change 4b 'Same as reference No change The results obtained with P1 acrylate grafted hyaluronic acid (Example 1), methacrylate grafted dextran P2, P3 (Example 2 and 3), P4 acrylate grafted carrageenan without thiol show that these polyme res exhibit a good tensor effect but the latter is not persistent in water. On the other hand, with post-treatment with a thiol such as dithiothreitol (examples la ', 2a', 3a ', 4a'), pentaerythritol tetra (3-mercaptopropionate) (Examples Ib ', 2b', 3b ', 4b' ), the tensor effect of the polymers after rinsing shows no change with respect to the tensor effect before rinsing. Post-treatment with the thiol compound thus makes it possible to obtain a remanent tensor effect. EXAMPLE 14 An anti-wrinkle gel is prepared having the following composition: polymer of Example 1 1 g-hydroxyethyl cellulose (NATROSOLO 250 HHR CS from Ashland) 0.5 g - Preservatives qs - Water qs 100 g A similar composition is also prepared using the polymer of Example 2.

Just before application to the skin, 1 g of an aqueous solution containing 1% by weight of cysteamine, based on the total weight of the solution, is added to the gel.

The composition obtained, mixed with cysteamine, applied to the face (approximately 20 mg of composition per cm 2 of treated skin) makes it possible to smooth wrinkles effectively.

EXAMPLE 15 A gel base coat is prepared having the following composition: polymer of Example 1 3.5 g Polyacrylamidomethyl propanesulfonic acid partially neutralized with ammonia and highly crosslinked (Hostacerin AMPS® from Clariant) 2 g Preservatives qs - Water qs 100 g. A similar composition is also prepared using the polymer of Example 2. The gel obtained is applied to the wrinkled skin of the face (approximately 20 mg of composition per cm 2 of treated skin). Then an aqueous solution (top coat) at 0.5% by weight of cysteamine is applied to the treated zone according to the following mass criteria: 26 μl of gel base coat and either 2.6 μl or 10.6 μl of solution top coat . After drying, the application of the 2 compositions on the face makes it possible to smooth wrinkles effectively.

EXAMPLE 16 An anti-wrinkle gel is prepared having the following composition: polymer of example 1 1 g-hydroxyethyl cellulose (NATROSOLO 250 HHR CS from Ashland) 0.5 g - Preservatives qs - Water qs 100 g A similar composition is also prepared using the polymer of Example 2. Just before application to the skin, 10 g of a 5% by weight aqueous solution of dithiothreitol, pH adjusted to 8 with dithiothreitol, are added to the gel. Ammonia. The composition obtained, mixed with dithiothreitol, applied to the face (approximately 20 mg of composition per cm 2 of treated skin) makes it possible to smooth wrinkles effectively.

EXAMPLE 17 An anti-wrinkle gel base gel is prepared having the following composition: polymer of Example 1 1 g-hydroxyethyl cellulose (NATROSOLO 250 HHR CS from Ashland) 0.5 g - Preservatives qs - Water qs 100 g similar composition is also prepared using the polymer of Example 2. The gel obtained is applied to the wrinkled skin of the face (about 20 mg of composition per cm 2 of treated skin). Then an aqueous gel (top coat) having the following composition is applied to the treated zone: Dithiothreitol 5 g Hydroxyethyl cellulose (NATROSOLO 250 HHR CS from Ashland) 0.5 g Preservative qs Perfume qs Ammonia qsp pH 8 Water qs 100 g After drying, the application of 2 compositions on the face can effectively smooth wrinkles.

EXAMPLE 18 An anti-wrinkle gel is prepared having the following composition: polymer of Example 3 1 g-hydroxyethyl cellulose (NATROSOLO 250 HHR CS from Ashland) 0.5 g - Preservatives qs - Water qs 100 g A similar composition is also prepared using the polymer of Example 4.

Just before application to the skin, 10 g of a 10% by weight ethanolic solution of pentaerythritol tetra (3-mercaptopropionate) are added to the gel. The composition obtained, mixed with pentaerythritol tetra (3-mercaptopropionate), applied to the face can effectively smooth wrinkles.

Claims (18)

REVENDICATIONS1. A cosmetic process for the care of the skin, more particularly of the skin of the face, in particular of the wrinkled skin, comprising: either the topical application to the skin of an extemporaneous mixture of a cosmetic composition comprising at least one grafted polysaccharide polymer of (meth) acrylate groups and of at least one crosslinking thiol compound having one or more thiol groups, ie the sequential application on the skin of a cosmetic composition comprising at least one polysaccharide polymer grafted with (meth) acrylate groups, followed by the application of at least one crosslinking thiol compound having one or more thiol groups, or a cosmetic composition containing it. 2. Method according to the preceding claim, characterized in that the grafted polysaccharide polymer has a degree of grafting ranging from 10 to 80%, preferably ranging from 40 to 70%. 3. Method according to one of the preceding claims, characterized in that the grafted polysaccharide polymer is selected from hyaluronic acid, dextran and carrageenan grafted (meth) acrylate. 4. Method according to one of the preceding claims, characterized in that the grafted polysaccharide polymer is selected from hyaluronic acid grafted with acrylate groups, dextran grafted with methacrylate groups, and carrageenan grafted with acrylate groups. 5. Method according to any one of the preceding claims, characterized in that the grafted polysaccharide polymer has a weight average molecular weight ranging from 5,000 to 1,000,000 daltons, preferably ranging from 10,000 to 500,000 daltons, preferably ranging from 15,000 at 350,000 daltons. 6. Method according to any one of the preceding claims, characterized in that the grafted polysaccharide polymer is present in the composition in a content ranging from 0.1 to 10% by weight, relative to the total weight of the composition, preferably from 0.5% to 10% by weight of active material, and preferably from 1% to 8% by weight, and more preferably from 1% to 6% by weight. 7. Process according to any one of the preceding claims, characterized in that the crosslinking thiol is chosen from: (i) non-polymeric organic compounds of formula (I) vv (SI-1) n (I) in which n denotes an integer greater than or equal to 2, preferably between 2 and 10, preferably between 2 and 5. and VV denotes a multivalent (at least divalent) radical 02-080 linear or branched or (hetero) cyclic, saturated, a radical aromatic, a heteroaromatic cyclic radical, VV may additionally contain one or more heteroatoms such as 0, N, S, and / or one or more functions selected from ester functions, ketones, amides, ureas, preferably esters, ketones) and and / or be substituted by one or more linear or branched C1-C10 alkyl, hydroxyl, amino, linear or branched C1-C10 alkyl (C1-C6 alkyl) amino, carboxylic, carboxylate or alkoxy groups, it being understood that when the VV radical is substituted , the functions t hiols may be carried by the substitute (s); (ii) the polymeric compounds of formula (II): POL (SH) n (II) in which n denotes an integer greater than or equal to 5, preferably between 5 and 5000, preferably between 5 and 1000, and POL denotes a multivalent (at least pentavalent) polymeric radical carbon or silicone, POL may further contain one or more heteroatoms such as 0, N, S, and / or one or more functions selected from the functions esters, ketones, amides, ureas , carbamates, and / or be substituted by one or more linear or branched C1-010 linear or branched C1-010 alkyl groups, it being understood that when POL is substituted, the thiol functions may be borne by the substituent (s) ); (Iii) aminothiols of formula (III): HS) -L- (NHR) b (III) wherein b denotes an integer ranging from 1 to 5, preferably from 1 to 3, and more preferably equal to at 1; L denotes a linear or branched (saturated) or saturated (hetero) cyclic (at least divalent) radical 02-080, an aromatic radical, a heteroaromatic cyclic radical, VV may also contain one or more non-adjacent heteroatoms such as O, N, S, and / or one or more functional groups selected from esters, ketones, amides, ureas, carbamates, preferably esters, ketones) and / or be substituted by one or more linear or branched, hydroxyl-substituted Cl-010 groups, linear or branched carboxylic, carboxylate, alkoxy Cl-010, it being understood that when the radical VV is substituted, the thiol functions can be borne by the substituent (s); R denotes a hydrogen atom or a C1-C6 alkyl radical, or OH300- or O2H5-40 CO-, and preferably a hydrogen atom. 8. Process according to any one of the preceding claims, characterized in that the crosslinking thiol is chosen from: 1,2-ethanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, 1,4-butanedithiol , 1,6-hexanedithiol, 1,7-heptanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, 1,10-decanedithiol, 1,12-dodecanedithiol, 2,2-dimethyl 1,3-propanedithiol, 3-methyl-1,5-pentanedithiol, 2-methyl-1,8-octanedithiol; 1,1,1-tris (mercaptomethyl) ethane, 2-ethyl-2-mercaptomethyl-1,3-propanedithiol, 1,2,3-propanetrithiol; bis (2-mercaptoethyl) ether, bis (2-mercaptoethyl) sulfide, bis- (2-mercaptoethylthio-3-mercaptopropane) sulfide; bis (2-mercaptoethylthio) methane, 1,2-bis (2-mercaptoethylthio) ethane, 1,3-bis (2-mercaptoethylthio) propane, 1,2-bis (2-mercaptoethylthio) propanethiol, 1 2-bis (2-mercaptoethyl) thio-3-mercaptopropane, 1,2,3-tris (2-mercaptoethylthio) propane; ethylene glycol bis (2-mercaptoacetate), ethylene glycol bis (3-mercaptopropionate), ethylene glycol bis (thioglycolate), trimethylolpropane tris (thioglycolate), trimethylolpropane tris (beta-mercaptopropionate), pentaerythritol tetrakis (thioglycolate) ), pentaerythritol tetrakis (.beta.-mercaptopropionate), dipentaerylthritol hexakis (.beta.-mercaptoproprionate), trimethylolpropane tris (2-mercaptoacetate), trimethylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (2-mercaptoacetate) pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptobutanate), dipentaerythritol hex-3-mercaptopropionate; tetrakis (2-mercaptoethylthiomethyl) methane, bis- (2-mercaptoethylthio-3-mercaptopropane) sulfide; 1,4-cyclohexane dithiol, 1,4-bis (mercaptomethyl) cyclohexane, 1,1-cyclohexane dithiol, 1,2-cyclohexane dithiol, 1,1-bis (mercaptomethyl) cyclohexane, 2,5 dimercapto-1,4-dithiane; tris ((mercaptopropionyloxy) -ethyl) isocyanurate; 1,2-dimercaptobenzene, 1,3-dimercaptobenzene, 1,4-dimercaptobenzene, 1,2-bis (mercaptomethyl) benzene, 1,3-bis (mercaptomethyl) benzene, 1,4-bis (mercaptomethyl) ) benzene, 1,2-bis (2-mercaptoethyl) benzene, 1,3-bis (2-mercaptoethyl) benzene, 1,4-bis (2-mercaptoethyl) benzene, 1,2-bis (2) -mercaptoethyleneoxy) benzene, 1,3-bis (2-mercaptoethyleneoxy) benzene, 1,4-bis (2-mercaptoethyleneoxy) benzene, 1,2,3-trimercaptobenzene, 1,2,4-trimercaptobenzene, 1,3,5-trimercaptobenzene, 1,2,3-tris (mercaptomethyl) benzene, 1,2,4-tris (mercaptomethyl) benzene, 1,3,5-tris (mercaptomethyl) benzene, 1, 2,3-tris (2-mercaptoethyl) benzene, 1,2,4-tris (2-mercaptoethyl) benzene, 1,3,5-tris (2-mercaptoethyl) benzene, 1,2,3-tris (2-mercaptoethyleneoxy) benzene, 1,2,4-tris (2-mercaptoethyleneoxy) benzene, 1,3,5-tris (2-mercaptoethyleneoxy) benzene, 1,2,3,4-tetramercaptobenzene, , 2,3,5-tetramercaptobenzene, 1,2,4,5-tetramercaptobenzene, 1,2,3,4-tetrakis (mercaptomethy l) benzene, 1,2,3,5-tetrakis (mercaptomethyl) benzene, 1,2,4,5-tetrakis (mercaptomethyl) benzene, 1,2,3,4-tetrakis (2-mercaptoethyl) benzene , 1,2,3,5-tetrakis (2-mercaptoethyl) benzene, 1,2,4,5-tetrakis (2-mercaptoethyl) benzene, 1,2,3,4-tetrakis (2-mercaptoethyleneoxy) benzene, 1,2,3,5-tetrakis (2-mercaptoethyleneoxy) benzene, 1,2,4,5-tetrakis (2-mercaptoethyleneoxy) benzene, 2,2'-dimercaptobiphenyl, 4,4'- dimercaptobiphenyl, 4,4'-dimercaptobibenzyl, 2,5-toluenedithiol, 3,4-toluenedithiol, 1,4-naphthalenedithiol, 1,5-naphthalenedithiol, 2,6-naphthalenedithiol, 2,7- naphthalenedithiol, 2,4-dimethylbenzene-1,3-dithiol, 4,5-dimethylbenzene-1,3-dithiol, 9,10-anthracenedimethanethiol, 1,3-bis (2-mercaptoethylthio) benzene, 4-bis (2-mercaptoethylthio) benzene, 1,2-bis (2-mercaptoethylthiomethyl) benzene, 1,3-bis (2-mercaptoethylthiomethyl) benzene, 1,4-bis (2-mercaptoethylthiomethyl) benzene, 1,2,3-tris (2-mercaptoethylthio) benzene, 1,2,4 tris (2-mercaptoethylthio) benzene, 1,3,5-tris (2-mercaptoethylthio) benzene, 1,2,3,4-tetrakis (2-mercaptoethylthio) benzene, 1,2,3,5- tetrakis (2-mercaptoethylthio) benzene, 1,2,4,5-tetrakis (2-mercaptoethylthio) benzene, 3,4-thiophenedithiol. dithiothreitol, 2,3-dimercapto-1-propanol; meso-2,3-dimercaptosuccinic acid and its C 1 -C 4 alcohol esters. cysteamine, N-acetylcysteamine, cysteine, N-acetylcysteine, homocysteine, compounds of formula HS- (CH2) n -NH- (CH2) m -NH2, n and m being integers ranging from 1-4, ortho-aminothiophenol, meta-aminothiophenol, para-aminothiophenol. 9. Method according to any one of the preceding claims, characterized in that the crosslinking thiol is selected from cysteamine, dithiothreitol, pentaerhytritol tetra (3-mercaptopropionate), and preferably cysteamine. 10. Method according to any one of the preceding claims, characterized in that the crosslinking thiol is carried out according to a molar ratio thiol crosslinking / (meth) acrylate group of the graft polysaccharide ranging from 0.01 to 10, preferably from 0.01 to 5. 11. Method according to any one of the preceding claims, characterized in that an extemporaneous mixture is applied to the skin carried out less than 5 minutes before application to the skin of the cosmetic composition comprising the grafted polysaccharide polymer (meth) acrylate and thiol crosslinker. 12. Process according to any one of Claims 1 to 10, characterized in that the cosmetic composition comprising the grafted (meth) acrylate polysaccharide is then applied to the skin and then the crosslinking thiol, or a cosmetic composition, is applied. container. 13. Method according to any one of the preceding claims, characterized in that the composition is in the form of an O / W emulsion or an aqueous gel. 14. Process according to any one of the preceding claims, characterized in that the composition comprising the crosslinking thiol is an aqueous composition having a pH ranging from 5 to 10.5, preferably ranging from 6 to 9, and preferably ranging from 7 to 8.5. 15. Method according to any one of the preceding claims, characterized in that it is intended to attenuate wrinkles. 16. Cosmetic use as tensor of the skin, in particular of wrinkled skin, of the mixture of a graft polysaccharide polymer as defined in any one of Claims 1 to 5 and of a crosslinking thiol such as as defined in one of claims 6 to 10. 17. Cosmetic composition obtained by mixing a cosmetic composition comprising a polysaccharide polymer grafted with (meth) acrylate groups as defined in any one of claims 1 to 5 and a crosslinking thiol as defined in one of the Claims 7 to 9, or a cosmetic composition containing it. 18. Kit comprising a first cosmetic composition comprising a polysaccharide polymer grafted with (meth) acrylate groups as defined in any one of claims 1 to 5 and a second composition comprising a crosslinking thiol as defined in one of claims 7. at 9, the first and second compositions being each packaged in a separate package.