FR3021542A1 - COSMETIC PROCESS FOR ATTENUATING WRINKLES - Google Patents

Abstract

The invention relates to a cosmetic method for the care of the skin, more particularly of the skin of the face, in particular of the wrinkled skin, comprising the topical application to the skin of a cosmetic composition comprising a carrageenan polymer grafted with groups ( meth) acrylate. The invention also relates to a carrageenan polymer composed of alternate units of (1 → 3) β-D-galactopyranose and (1 → 4) α-galactopyranose sulfated grafted with (meth) acrylate groups; its preparation process and a composition comprising in a physiologically acceptable medium such a polymer.

Description

The present invention relates to a method, especially a cosmetic skin care method, for attenuating wrinkles, comprising the application to the skin of a composition comprising a grafted carrageenan polymer, and the use of this polymer as an agent. tensor of the skin.

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.

Carrageenan is known for its tensor properties of the skin, especially in the document FR-A-2838343. The inventors have discovered that a carrageenan polymer grafted with (meth) acrylate groups has an improved tensor effect on the skin and thus makes it possible to attenuate the wrinkles of the skin immediately. In addition, when the carrageenan grafted with (meth) acrylate groups is associated with a particular amino compound, the tensor effect obtained is further improved and this effect also has good water resistance and therefore good afterglow. water.

Polymers of kappa-carrageenan grafted with methacrylate groups are described in the publication S. Mihaila et al. "Photocrosslinkable Kappa-Carrageenan hydrogels for tissue engineering applications", Advanced Healthcare Materials, 2013, 2, 895-907. . They used to form after crosslinking hydrogels.

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 the topical application to the skin of a composition. , in particular cosmetic, comprising a carrageenan polymer grafted with (meth) acrylate groups.

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

According to one embodiment of the process according to the invention, the topical application to the skin is carried out of an extemporaneous mixture of a composition, in particular a cosmetic composition, comprising a carrageenan polymer grafted with (meth) acrylate groups and an amine compound, or a composition, in particular a cosmetic composition, containing it, as defined hereinafter.

According to another embodiment of the method according to the invention, the sequential application on the skin of a composition, in particular a cosmetic composition, comprising a carrageenan polymer grafted with (meth) acrylate groups and an amine compound, is carried out. or a cosmetic composition containing it, as defined below.

The subject of the invention is also the cosmetic use as a skin tightening agent, in particular of a wrinkled skin, of a grafted carrageenan polymer, optionally mixed with the amine compound, as defined above. after.

The subject of the invention is also a carrageenan polymer composed of alternating units of (1 → 3) pD-galactopyranose and sulfated (1 → 4) α-galactopyranose grafted with (meth) acrylate groups, in particular from grafted carrageenan of grafted α-carrageenan, grafted v-carrageenan, and preferably grafted β-carrageenan.

The invention also relates to a process for the preparation of a grafted carrageenan polymer comprising the reaction of a carrageenan composed of alternating units of (1-> 3) pD-galactopyranose and (1-> 4) a- sulfated galactopyranose with (meth) acrylic anhydride, preferably with acrylic anhydride.

The invention also relates to a composition comprising in a physiologically acceptable medium a grafted carrageenan polymer as described above. The subject of the invention is also a composition, in particular a cosmetic composition, obtained by mixing a cosmetic composition comprising said grafted carrageenan polymer as described above and an amino compound as defined above, or a composition, in particular cosmetic, the container. The subject of the invention is also a kit comprising a first composition, in particular a cosmetic composition, comprising said grafted carrageenan polymer as described above and a second composition comprising an amino compound as described above, the first and second compositions being each packaged in a separate packaging set.

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 skin treatment method according to the invention. The term "tensioning agent" means compounds likely to have an apparent tensing effect, that is to say to smooth the skin and reduce or even eliminate, immediately wrinkles and fine lines.

The tensor effect can be characterized by an in vitro retraction test as described in Example 2. Carrageenans are sulfated polysaccharides which constitute 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 comprise 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 moiety may be sulfated one or more times at the 2, 3, 4 or 6 position. Methyl groups, pyruvic acid groups and other sugar moieties grafted to the previously described base structures 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 are the following carrageenans: Carrageenan (1-> 3) 13-D-galactopyranose-4-sulphate- (1-> 4) -oc-D-galactopyranose -6- Sulfate Carrageenan (1 -> 3) 13 -D-galactopyrano-4-sulphate- (1 -> 4) 3, 6-anhydro-oc-D-galactopyranose OH OH Alkaline treatment 3021542 4 O OS OH OS0, - Alkaline treatment: ## STR5 ## Carrageenan (1 → 3) -D-galactopyrano-4-sulphate- (1 → 4) -oc-D-galactopyranose -2,6-disulphate I-carrageenan ( 1-> 3) 13-D-Galactopyranose-4-Sulfate- (1-> 4) 3,6-Anhydro-α-D-galactopyranose-2-Sulfate OH OS0, - Alkaline-Carrageenan Treatment (1 - > 3) -D-galactopyrano-2-sulphate- (1 → 4) -oc-D-galactopyranose -2,6-disulphate-O-carrageenan (1-> 3) (3-D-galactopyranose-2-sulphate- ( These carrageenans are thus often obtained in the form of mixtures of different structures such as, and not limited to, mixtures of forms 143. carrageenan In particular, the carrageenans which are particularly suitable for the implementation of the invention are carrageenans of the type v, X. Carrageenans of the type K, V, i, X, 0 are preferably used. Carrageenan lambda is preferably used. .

The carrageenans of the present invention may be used in acidic or 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 of from 10,000 to 1,000,000 daltons, more preferably from 10,000 to 500,000 daltons, and even more preferably from 15,000 to 350,000 daltons. The molecular weight can be determined in particular by liquid phase chromatography, eluent 0.1 M sodium chloride and 330 mg / l of sodium azide in water, 35 dextran standard, WYATT OPTILAB T-Rex refractometer detectors and diffusion of light DAWN-HELEOS II - WYATT.

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 preferentially 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 on the 3 hydroxyls of the repeat 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. ## STR5 ## Various grafting levels with the (meth) acrylate groups can be obtained by varying the amount of anhydride (## STR1 ## meth) acrylic in proportion to the amount of carrageenan. Advantageously, a carrageenan is chosen which is chosen from p-carrageenan, acaragenan, v-carrageenan and, preferably, λ-carrageenan.

The grafted carrageenan polymer as defined above may be present in the composition used according to the invention in a content ranging from 0.1 to 10% by weight, relative to the total weight of the composition, preferably 0.5 % to 10% by weight of active material, and preferably ranging from 1% to 8% by weight, and more preferably from 1% to 6% by weight.

According to one embodiment of the process according to the invention, an extemporaneous mixture of the graft polymer and an amine compound is produced and the mixture is applied to the skin. Sequential application can also be performed on the one hand of the graft polymer and on the other hand of the amine compound.

The amino compound used in the process according to the invention is chosen from amine compounds having one or more primary amine groups and / or secondary amine groups. It can therefore be chosen from monoamino compounds, diamines, triamines or polyamines.

According to a first embodiment of the invention, the amine compound is a compound comprising from 2 to 20 carbon atoms, especially a non-polymeric compound. By non-polymeric compound is meant a compound which is not directly obtained by a polymerization reaction of monomers.

Amino compounds which may be mentioned are n-butylamine, tert-butylamine, isobutylamine, propylamine, n-hexylamine, glycine, ethanolamine, 3-aminopropanol, dopamine, 7-amino-4-methylcoumarin. 1,4-bis (3-aminopropyl) piperazine, 3-aminopropyltriethoxysilane (APTES), 3-aminophenylboronic acid, N-methyl-1,3-diaminopropane, 1,3-N-propyl diaminopropane, N-isopropyl 1,3-diaminopropane, N-cyclohexyl 1,3-diaminopropane, 2- (3-aminopropylamino) ethanol, 3- (2-aminoethyl) aminopropylamine, bis (3-aminopropyl) amine , methyl bis (3-aminopropyl) amine, N- (3-aminopropyl) -1,4-diaminobutane, N, N-dimethyldipropylene triamine, 1,2-bis (3-aminopropylamino) ethane, N, N'-bis (3-aminopropyl) -1,3-propanediamine, ethylene diamine, 1,3-propylenediamine, 1,4-butylenediamine, lysine, cystamine, xylenediamine, tris (2) -aminoethyl) amine, spermidine. Preferably, the amine compound is selected from n-butylamine, 3-aminopropanol, dopamine, 7-amino-4-methylcoumarin, 1,4-bis (3-aminopropyl) piperazine, 3-aminopropyltriethoxysilane (APTES ), 3-amino phenylboronic acid, N-methyl-1,3-diaminopropane, N-propyl-1,3-diaminopropane, N-isopropyl-1,3-diaminopropane, 1,3-N-cyclohexyl, diaminopropane, 2- (3-aminopropylamino) ethanol, 3- (2-aminoethyl) aminopropylamine, bis (3-aminopropyl) amine, methyl bis (3-aminopropyl) amine, N- (3-aminopropyl) - 1,4-diaminobutane, N, N-dimethyldipropylene triamine, 1,2-bis (3-aminopropylamino) ethane, N, N'-bis (3-aminopropyl) -1,3-propanediamine, ethylene diamine, lysine. The amino compound may also be chosen from amino polymers, especially having a weight average molecular weight ranging from 500 to 1,000,000, preferably from 500 to 500,000, and preferably ranging from 500 to 100,000.

As the amine polymer, it is possible to use the poly (C2-C5 alkylene imines), and in particular the polyethyleneimines and the polypropyleneimines, in particular the poly (ethyleneimine) (for example that sold under the reference 46,852-3 by the company). Aldrich Chemical); poly (allylamine) (for example that sold under the reference 47,913-6 by Aldrich Chemical); polyvinylamines and their copolymers, especially with vinylamides; mention may especially be made of vinylamine / vinylformamide copolymers such as those sold under the name Lupamine® 9030 by the company BASF; amino polyacids having NH 2 groups such as polylysine, for example that sold by JNC Corporation 10 (formerly Chisso); dextran amino, such as that sold by CarboMer Inc; polyvinyl amino alcohol such as that sold by CarboMer Inc., copolymers based on acrylamidopropylamine; chitosan; Polydimethylsiloxanes comprising primary amino groups at the chain end or on side chains, for example terminal or lateral aminopropyl groups, for example those of formula (A) or (B) or (C): (A) (B) ) H2NCH2CH2CH2-Si (CH3) 2-0- [Si (CH3) 2-O] n-Si (CH3) 2C4Hg (C) in the formula (A): the value of n is such that the weight average molecular weight silicone is between 500 and 55,000. Examples of aminosilicone (A) include those sold under the names "DMS-A11", "DMS-Al2", "DMS-A15", " DMS-A21 "," DMS-A31 "," DMS-A32, "DMS-A35" by the company GELEST. in the formula (B), the values of n and m are such that the weight average molecular weight of the silcione is between 1000 and 55,000. Examples of silicone examples (B) are those sold under the names " AMS-132 "," AMS-152 "," AMS-162 "," AMS-163 "," AMS-191 "," AMS-1203 "by the company GELEST. in the formula (C), the value of n is such that the weight average molecular weight of the silicone is between 500 and 3000. Examples of silicone (C) include those sold under the names "MCR-A11 "," MCR-Al2 "by the company 10 GELEST. amodimethicones of formula (D): ## STR2 ## wherein R, R 'and R " , identical or different, each represents a C 1 -C 4 alkyl or hydroxyl group, A represents a C 3 alkylene group and m and n are such that the weight average molecular weight of the compound is between about 5,000 and 500,000.

Polyether amines, especially known under the reference JEFFAMINE from the company H UNSTMAN; and especially: polyethylene glycol and / or polypropylene glycol end amine function (monamine or diamine) such as those sold under the names JEFFANINE M600, M-1000, M-2005, M-2070, D-230, D-400, D-2000, D-4000, ED-600, ED-9000, ED-2003 Polytetrahydrofuran (or polytetramethylene glycol) end-amine-functional (monoamine or diamine), end-amine-functional polybutadienes (monoamine or diamine) Dendrimers and hyperbranched polymers with primary or secondary amine function (PANAM) Poly (meth) acrylates or poly (meth) acrylamides bearing primary or secondary secondary amine functions such as poly (3-aminopropyl) methacrylamide, poly (2-aminoethyl) methacrylate.

The aminated polymer used is preferably polyethylene imine, polylysine, chitosan, polyethylene oxide and / or propylene oxide with terminal amine groups.

Preferably, the amine compounds used in the process according to the invention are chosen from ethylene diamine, lysine and 3-aminopropyltriethoxysilane (APTES). More preferably, use is made of ethylenediamine. Advantageously, the amine compound used in the process according to the invention is used according to a molar ratio of amine compound / grafted carrageenan (meth) acrylate group ranging from 0.1 to 10, preferably from 0.1 to 5. and preferably from 0.1 to 2. The amino compound in contact with the grafted carrageenan reacts with the ethylenic unsaturations of the (meth) acrylate groups grafted on the carrageenan to form amine bonds with the terminal carbon of the ethylenic unsaturation. (meth) acrylate group (this reaction is known as the Michael reaction). Examples of this reaction are illustrated in the following schemes: ## STR2 ## R = H or COCH = CH 2 R = H or COCH = CH 2 H, NR = H or COCH = CH 2 Crosslinking NH, R = H or COCH = CH 2 When the grafted carrageenan comprises methacrylate groups, a catalyst may be used presence of the amino compound. This catalyst makes it possible to obtain a good reactivity of the amine 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 composition used according to the invention is generally suitable for topical application to the skin and therefore generally comprises a physiologically acceptable medium, that is to say a medium compatible with the skin and / or its integuments. It is preferably a cosmetically acceptable medium, that is to say which has a pleasant color, odor and feel and which does not generate unacceptable discomfort (tingling, tightness, redness), which is susceptible to divert the consumer from using this composition. The composition according to the invention may be in any of the galenical forms conventionally used for topical application and in particular in the form of aqueous lotion or gel type dispersions, emulsions of liquid or semi-liquid consistency of the milk type, obtained by dispersion of 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 composition is in the form of an O / W emulsion or an aqueous gel.

Advantageously, the composition used according to the invention comprises water, especially 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 composition used according to the invention may furthermore 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 in such a way that the anti-wrinkle 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 cosmetic composition comprising the grafted carrageenan (meth) acrylate polymer and an amine 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 cosmetic composition comprising the grafted carrageenan (meth) acrylate polymer is first applied to the skin, and then the amine compound or a cosmetic composition containing it is applied. The application of the amino compound can be carried out after a time of between 5 minutes and one hour after applying the grafted carrageenan polymer. According to a third embodiment of the process according to the invention, the amine compound, or a cosmetic composition containing it, is first applied to the skin and then the cosmetic composition comprising the grafted carrageenan (meth) acrylate polymer is applied. The application of the grafted carrageenan polymer can be carried out after a time of between 5 minutes and one hour after having applied the amine compound. 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. 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 not limiting. Example 1 Carrageenan Functionalized at 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 40) 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 weight) on Spectra / Por® membrane 15 kDa for 5 days in 5 liters of water (water 3021542 12 changed 4 times or 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 D20: 0.44 functionalized OH units for 3 available OH units. The carrageenan obtained is functionalized at 10% with acrylate groups.

EXAMPLE 2 Demonstration of the tensor effect of the polymers used according to the invention This test consists of comparing in vitro the tensing power of the polymer 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 an interpenetrating network of polyurethane and acrylic polymers). The polymer to be evaluated is 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. An aqueous solution containing the polymer to be evaluated is thus deposited on the elastomer strip, depositing 1.8 mg (of 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 and on another strip 104 μl of an aqueous solution containing 1% is deposited. 75% MA of carrageenan functionalized acrylate to be evaluated After drying for 24 hours at room temperature (25 ° C.), the bending (retraction) of the strip treated with the carrageenan polymer was observed in comparison with that obtained with the control ( Hybridur® 875). The tensor effect of the graft polymer in the presence of ethylene diamine was also evaluated. An aqueous solution containing 1% by weight of ethylene diamine was prepared. The acrylate grafted carrageenan solution (1.75% MA) and the ethylene diamine 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 ethylene diamine (molar equivalents) relative to the acrylate groups Amount of Volume Volume of the ethylene / carrageenan solution of the mixing solution taken for diamine (pL) acrylate The tensor effect obtained according to the previously described protocol was measured as a strip 1 (pL) 1 to 0.5 29.6 312 113.8 1b 0.1 5.9 312 106. Then, the water resistance of the tensor effect was evaluated by immersing the rubber strips treated with the polymer to be evaluated in water at room temperature 25 ° C. The unmodified carrageenan was also evaluated. The following results were obtained: Polymer tested Tensor effect Tensor effect after immersion in water Hybridure 875 correct correct Example 1 above the reference Below the reference Example the comparable to the reference greater than the reference Example 1 b Comparable to the The results obtained show that the carrageenan polymer of Example 1 mixed with 0.1 (ex 1 b) and 0.5 (ex la) equivalent, respectively, is lower than the reference Carrageenan. molar ethylene diamine has a good tensor effect. The tensor effect obtained is greater than that of unmodified carrageenan. In example 1a, the polymer also has a good tensing effect after immersion in water.

EXAMPLE 3 An anti-wrinkle gel was prepared having the following composition: polymer of Example 1 1 g-hydroxyethyl cellulose (NATROSOL® 250 HHR CS from Ashland) 0.5 g - Preservatives qs 5 - Water qs 100 g The resulting composition applied to the face can effectively smooth wrinkles. EXAMPLE 4 An anti-wrinkle gel was prepared having the following composition: polymer of Example 1 1 g-hydroxyethyl cellulose (NATROSOL® 250 HHR CS from Ashland) 0.5 g 15 - Preservatives qs - Water qs 100 Just before application to the skin, 90 mg of ethylene diamine is added to the gel.

The composition obtained, mixed with ethylene diamine, applied to the face effectively smoothes wrinkles.

Claims (26)

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 the topical application to the skin of a cosmetic composition comprising a carrageenan polymer grafted with (meth) acrylate groups. 2. Method according to the preceding claim, characterized in that the grafted carrageenan polymer has a degree of grafting ranging from 2 to 60%, preferably ranging from 2 to 50%, and preferably ranging from 5 to 30%. 3. Process according to claim 1 or 2, characterized in that the carrageenan polymer is grafted with acrylate groups. 15 4. Process according to any one of the preceding claims, characterized in that 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 from 15,000 to 350,000 daltons. 20 5. Method according to any one of the preceding claims, characterized in that the carrageenan 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. 25 6. Method according to any one of the preceding claims, characterized in that the topical application is carried out on the skin of an extemporaneous mixture of the cosmetic composition comprising the carrageenan polymer grafted with (meth) acrylate groups and an amino compound having one or more primary amine and / or secondary amine groups, or a cosmetic composition containing it. 7. Process according to any one of the preceding claims, characterized in that the sequential application on the skin of the cosmetic composition comprising the carrageenan polymer grafted with (meth) acrylate groups and an amino compound is carried out. having one or more primary amine and / or secondary amine groups, or a cosmetic composition containing it. 8. Process according to any one of claims 6 or 7, characterized in that the amine compound comprises from 2 to 20 carbon atoms. 40 9. Process according to any one of claims 6 to 8, characterized in that the amine compound is chosen from n-butylamine, tert-butylamine, isobutylamine, propylamine, n-hexylamine, glycine, and the like. ethanolamine, 3-aminopropanol, dopamine, 7-amino-4-methylcoumarin, 1,4-bis (3-aminopropyl) piperazine, 3-aminopropyltriethoxysilane (APTES), 3-aminophenylboronic acid, N-aminopropyltriethoxysilane methyl-1,3-diaminopropane, N-propyl-1,3-diaminopropane, N-isopropyl-1,3-diaminopropane, N-cyclohexyl-1,3-diaminopropane, 2- (3-aminopropylamino) ethanol, 3- (2-aminoethyl) aminopropylamine, bis (3-aminopropyl) amine, methyl bis (3-aminopropyl) amine, N- (3-aminopropyl) -1,4-diaminobutane, N, N-dimethyldipropylene triamine , 1,2-bis (3-aminopropylamino) ethane, N, N'-bis (3-aminopropyl) -1,3-propanediamine, ethylene diamine, 1,3-propylenediamine, 1,4-bis (3-aminopropyl) -1,3-propanediamine, butylenediamine, lysine, cystamine, xylene diamine, tris (2-aminoethyl) amine, spermidine; and preferably selected from ethylene diamine, lysine, 3-aminopropyltriethoxysilane, and preferably is ethylenediamine. 10. Process according to any one of claims 6 to 9, characterized in that the amine compound is chosen from amino polymers, especially having a weight average molecular weight ranging from 500 to 1,000,000, preferably from 500 to 500 000, and preferably ranging from 500 to 100 000. 11. Method according to the preceding claim, characterized in that the amine compound is an aminated polymer chosen from poly (C2-05) alkylene imines), and in particular polyethyleneimines and polypropyleneimines, especially poly (ethylene imine); poly (allylamine); polyvinylamines and their copolymers, especially with vinylamides; vinylamine / vinylformamide copolymers; polyamino acids having NH 2 groups such as polylysine; dextran amino; polyvinyl amino alcohol, copolymers based on acrylamidopropylamine; chitosan; polydimethylsiloxanes comprising primary amino groups at the chain end or on side chains, for example terminal or lateral aminopropyl groups, for example those of formula (A) or (B) or (C): (A) 3021542 17 ( B) H2 NC H2C H2C H2-S1 (CH3) 2-0- [Si (CH3) 2-O] n-Si (CH3) 2C4Hg (C) with: in formula (A): the value of n is such that the weight average molecular weight of the silicone is between 500 and 55,000. In the formula (B), the values of n and m are such that the weight average molecular weight of the silicone is between 1000 and 55,000. In the formula (C), the value of n is such that the weight average molecular weight of the silicone is between 500 and 3000; amodimethicones of formula (D): ## STR2 ## wherein R, R 'and R " , identical or different, each represents a C1-C4 alkyl or hydroxyl group, A represents a C3 alkylene group and m and n are such that the weight average molecular weight of the compound is between about 5,000 and 500,000. Amine polyethers and in particular polyethyleneglycol and / or polypropylene glycol with an amine function at the chain end (monamine or diamine); polytetrahydrofuran (or polytetramethylene glycol) end-amine amine function (monoamine or diamine), end-amine-functional polybutadienes (monoamine or diamine), dendrimers and hyperbranched polymers with primary or secondary amine function, poly (meth) acrylates or poly (meth) acrylamides bearing primary or secondary side amine functions such as poly (3-aminopropyl) methacrylamide, poly (2-aminoethyl) methacrylate; and preferably polyethylene imine, polylysine, chitosan, polyethylene oxide and / or propylene oxide with terminal amine groups. 10 12. Process according to any one of claims 6 to 11, characterized in that the amine compound is used according to a molar ratio of amine compound / grafted carrageenan (meth) acrylate group ranging from 0.1 to 10, preferably ranging from 0.1 to 5, and preferably ranging from 0.1 to 2. 13. A method according to any one of claims 6, 8 to 12, characterized in that it applies to the skin an extemporaneous mixture made less than 5 minutes before application to the skin of the cosmetic composition comprising the polymer of grafted carrageenan (meth) acrylate and the amine compound, or a cosmetic composition containing it. 20 14. Process according to any one of Claims 7 to 12, characterized in that the cosmetic composition comprising the grafted carrageenan (meth) acrylate polymer is applied to the skin first and then the amine compound or a composition is applied. cosmetic containing it. 25 15. Process according to any one of Claims 7 to 12, characterized in that the amine compound, or a cosmetic composition containing it, is applied to the skin first, then the cosmetic composition comprising the polymer of 30 is applied. carrageenan grafted (meth) acrylate. 16. Process 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. 17. Method according to any one of the preceding claims, characterized in that it is intended to reduce wrinkles. 18. Cosmetic use as skin tightening agent, in particular wrinkled skin, of a grafted carrageenan polymer as defined in any one of Claims 1 to 5 and optionally in admixture with an amino compound as defined in one of claims 6 to 12. 3021542 19 19. Carrageenan polymer composed of alternating units of (1-> 3) -3-D-galactopyranose and sulfated (1 → 4) -α-galactopyranose grafted with (meth) acrylate groups, preferably acrylate groups. 5 20. Polymer according to the preceding claim, characterized in that the grafted carrageenan polymer has a degree of grafting ranging from 2 to 60%, preferably from 2 to 50%, and preferably ranging from 5 to 30%. 21. The polymer as claimed in claim 19, wherein 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. Polymer according to any of claims 19 to 21, characterized in that the grafted carrageenan polymer is selected from grafted p-carrageenan, grafted carrageenan, grafted v-carrageenan, and preferably grafted graftane. 23. A process for the preparation of a grafted carrageenan polymer comprising reacting a carrageenan composed of alternate units of (1 → 3) -3-D-galactopyranose and sulfated (1 → 4) α-galactopyranose with (meth) acrylic anhydride, preferably with acrylic anhydride; preferably, the carrageenan is chosen from p-carrageenan, À-carrageenan and varcargenane, and preferably À-carrageenan. 25 24. A composition comprising in a physiologically acceptable medium a polymer according to one of claims 19 to 22. 25. Cosmetic composition obtained by mixing a cosmetic composition according to claim 24 and an amino compound as defined in one of claims 6 to 12, or a cosmetic composition containing it. 26. A kit comprising a first cosmetic composition according to claim 24 and a second composition comprising an amino compound as defined in any one of claims 1 and 6 to 10, the first and second compositions each being packaged in a separate package. .