Cosmetic composition comprising an alginate-based elastic mixture

Abstract

The invention relates to a composition comprising a mixture capable of forming a flexible elastic film, said composition comprising at least one polysaccharide selected from: a- at least one alginate, an alginate derivative, or mixtures thereof; b- at least one modified polysaccharide; and c- at least one polyol selected from diols, polyglycerols of formula H-(O-CH2-CH(OH)-CH2)n-OH, in which n varies from 1 to 10, and mixtures thereof. The composition provides a tensioning effect and deforms elastically in order to follow the mechanical deformations and movements of the skin's surface. The present invention also relates to a method for preparing a cosmetic composition according to the invention, and to a skin care method comprising a step of applying a cosmetic composition according to the invention to the skin.

Description

Description Title of the invention: Cosmetic composition comprising an elastic alginate-based mixture Technical Field The present invention relates to the cosmetic field, and more particularly to a cosmetic composition comprising a mixture capable of forming an elastic film, which provides a tightening effect and deforms elastically to follow the movements and mechanical deformations of the skin surface. The present invention also relates to a method for preparing a cosmetic composition according to the invention, as well as a skincare method comprising a step of applying a cosmetic composition according to the invention to the skin.

[0002] Giving cosmetic formulations a smoothing effect is a well-established technique in cosmetology. This is achieved using active ingredients that penetrate the skin and provide long-lasting action. Film-forming polymers are also used for a smoothing effect, offering immediate mechanical action on the skin's surface. However, these smoothing materials have some drawbacks. First, once applied to the skin, the product is often uncomfortable due to the rigidity of the films formed. This rigidity makes the films inelastic and not very stretchable, consequently leading to poor durability of the cosmetic formulations, which quickly crack and crumble.

[0003] The Applicant has already described in application WO 2013 / 167835 a cosmetic treatment providing a tightening and smoothing effect comprising a specific elastic complex made up of at least one gelling or thickening starch, at least one polyol, and at least one polymer selected from polyvinyl alcohols, vinylpyrrolidone polymers and copolymers, and latex. However, these compositions have the disadvantage of being too sticky; they also lack adhesion to the skin (peelability problem).

[0004] The inventors have now developed a cosmetic composition comprising a blend of specific compounds capable of forming an elastic film with an immediate, visible, and lasting smoothing effect. The film thus formed can deform reversibly, so that after deformation, for example, after stretching, it returns to the state it had before the application of the mechanical stress provided, for example, by skin deformation. The film formed by the cosmetic composition containing this blend has greater resistance to breakage, which allows the mechanical properties of the film formed on the skin's surface to remain intact. Once incorporated into a cosmetic composition, the blend capable of forming this elastic film has an enhanced combined tightening and elastic effect, able to follow the skin's movements without cracking.The resulting effect is comparable to a tightening effect, as the cosmetic composition of the invention provides elasticity to skin naturally subjected to deformations, such as changes in facial expression or contact with hands or clothing. The inventors have thus succeeded in developing a cosmetic composition capable of combining performance characteristics that are difficult to reconcile: a tightening effect combined with an elastic effect, resolving the tightening / elasticity paradox. The new cosmetic composition is capable of effectively smoothing the skin's surface, notably achieving partial or total erasure of wrinkles, including medium and deep wrinkles.

[0005] The cosmetic composition of the invention exhibits remarkable skin-tightening and elasticizing properties, which are linked to the simultaneous presence of an alginate, a modified polysaccharide, and a polyol. The resulting cosmetic composition provides a visible and lasting smoothing of the skin's surface with exceptional user comfort. Furthermore, the nature of the ingredients used makes the cosmetic composition of the invention easy to formulate. General description of the invention

[0006] The present invention has as its first object a cosmetic composition which comprises a mixture capable of forming an elastic film comprising: a- at least one alginate, an alginate derivative, or mixtures thereof, b- at least one modified polysaccharide, and c- at least one polyol selected from diols, polyglycerols of formula H- (O-CH2-CH(OH)-CH2)n-OH in which n varies from 1 to 10, and mixtures thereof.

[0007] In the following description, the term "cosmetic composition" refers both to the cosmetic composition according to the invention and to the cosmetic composition used in the process of the invention. The terms "elastic mixture" and "mixture capable of forming an elastic film" are used interchangeably in this description.

[0008] The elastic blend of the cosmetic composition of the invention comprises an α-alginate, also known as a contractile film-forming polymer, which provides an immediate smoothing / tightening (lifting) effect. This contractile effect occurs upon drying, as hydrogen bonds form between the polymer chains to create contraction.

[0009] A polymer is said to be film-forming within the meaning of the invention if, after evaporation of the volatile substances present in the medium, a continuous and homogeneous film is observed to form. Intermolecular bonds, responsible for the mechanical properties, then form between the polymer chains and with other components such as plasticizers to create a film that does not penetrate the skin and provides resistance to water and sebum, non-transfer, etc.

[0010] The alginate of the invention can be selected from sodium alginate (INCI name: ALGIN), potassium alginate (INCI name: POTASSIUM ALGINATE), ammonium alginate (INCI name: AMMONIUM ALGINATE), sodium alginate sulfate (INCI name: SODIUM ALGINATE SULFATE), propylene glycol alginate (INCI name: PROPYLENE GLYCOL ALGINATE), triethanolamine alginate (INCI name: TEA-ALGINATE), and mixtures thereof. Advantageously, the alginate of the invention is sodium alginate (INCI name: ALGIN), for example, marketed under the reference GELCARIN® FF 46 by IFF. [OOllJAccording to one embodiment, the cosmetic composition of the invention comprises from 0.1 to 15%, preferably from 0.1 to 10%, and more preferably from 0.5 to 5%, by weight of alginate a- relative to the total weight of said cosmetic composition.

[0012] The elastic mixture of the cosmetic composition of the invention also comprises a modified β-polysaccharide, also called an elastic film-forming polymer, which provides an elastic (comfortable) effect to the composition. The modified β-polysaccharide of the invention has the advantage of providing, when mixed with the other ingredients, a dry, elastic film that is transparent and remains transparent after undergoing mechanical deformation (stretching). In particular, the film formed on the skin retains its transparency under repeated mechanical stress, so that it does not, over time, alter the color of the cosmetic composition deposited on the skin into which the mixture has been incorporated.

[0013] The modified β- polysaccharide, distinct from α- alginate, is advantageously a modified starch. The modified starches of the invention are obtained from native starches that have been modified chemically and / or physically and / or enzymatically to improve their elastic properties. The native starches can be derived from a wide variety of sources, such as, for example, starches from maize, wheat, rice, buckwheat, barley, oats, millet, rye, sorghum, cassava, potato, sweet potato, tapioca, banana, plantain, malanga, tara, chestnut, beans, peas, and preferably native starches from maize, wheat, rice, cassava, potato, tapioca, and peas.

[0014] The modified starches used in the invention have the advantage of producing, when mixed with the other components of the invention, elastic dry films that are transparent and remain transparent after stretching when prepared as thin films (typically less than one millimeter thick). Indeed, it is particularly advantageous in the context of the present invention that the film formed on the skin by application of the cosmetic composition of the invention retains its transparency under the effect of multiple mechanical stresses, and does not disturb the color of the deposit on the skin over time.

[0015] The modified β- polysaccharide advantageously has a weight-average molecular weight greater than or equal to 10 6 g. mol -1 , and preferably 10 6 at 10 9 g. mol 1The weight-average molecular weight can be determined by HPSEC-MALLS (high-performance size exclusion chromatography coupled online with multi-angle laser light scattering detection).

[0016] Among the preferred modified starches are alkylated starches, hydroxyalkylated starches, acetylated starches, and mixtures thereof, and more preferentially hydroxyalkylated starches.

[0017] The modified β- polysaccharide is advantageously selected from among hydroxyalkylated starches. In a preferred embodiment, the modified β- polysaccharide is hydroxypropyl starch, which may have the INCI name: HYDROXYPROPYL STARCH, such as the Beauté By Roquette® ST 720 and ST 730 products marketed by the ROQUETTE company.

[0018] In a particularly preferred embodiment, the modified β- polysaccharide is a hydroxyalkylated starch, and even more preferably a hydroxypropyl starch, having a weight-average molecular weight greater than or equal to 10 6 g. mol -1 , and advantageously by 10 6 at 10 9 g. mol -1 In one embodiment, the hydroxypropyl starch has a weight average molecular weight of 10 6 at 10 7 g. mol -1 , as is the case with the product Beauté By Roquette® ST 720 marketed by the company ROQUETTE. In a particularly advantageous embodiment, hydroxypropyl starch has a weight average molecular weight of 10 8 at 10 9 g. mol 1 , as is the case with the product Beauté By Roquette® ST 730 marketed by the company ROQUETTE. The average molecular weight by weight can be determined by HPSEC-MALLS.

[0019] The modified b- polysaccharide preferably represents 0.5 to 15%, preferably 0.5 to 10%, and more preferably 1 to 8%, by weight relative to the total weight of the cosmetic composition.

[0020] The elastic blend of the cosmetic composition of the invention also includes a c-polyol, which aids in the dispersion and plasticizes the polymers present in the cosmetic composition. Thus, the c-polyol acts as a plasticizer by providing mobility between the polymer chains, making them more elastic and flexible.

[0021] The c- polyol of the invention is selected from diols, polyglycerols of formula H-(O-CH2-CH(OH)-CH2)n-OH in which n varies from 1 to 10, and preferably from 1 to 6, and their mixtures.

[0022] According to another embodiment, the c- polyol is a polyglycerol of formula H-(O-CH2-CH(OH)-CH2)n-OH in which n varies from 1 to 10, and preferably from 1 to 6, and their mixtures.

[0023] According to an advantageous embodiment, the c- polyol is a polyglycerol with the formula H-(O-CH2-CH(OH)-CH2)n-OH in which n = 1 (INCI name: GLYCERIN), n = 3 (INCI name: POLYGLYCERIN-3), or n = 6 (INCI name: POLYGLYCERIN-6), and more advantageously, a polyglycerol with the formula H-(O-CH2-CH(OH)-CH2)n-OH in which n = 1 (INCI name: GLYCERIN) or n = 3 (INCI name: POLYGLYCERIN-3). POLYGLYCERIN-3 (PGL-S MB) and POLYGLYCERIN-6 (POLYGLYCERIN 500 MB) are marketed, for example, by the company SAKAMOTO YAKUHIN KOGYO.

[0024] According to one embodiment, the c- polyol is a diol selected from among the C2-C12 aliphatic or aromatic, linear or branched diols, preferably propane-1,2-diol, propane-1,3-diol, butane-1,2-diol, butane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, octane-1,8-diol, and mixtures thereof, and more preferably propane-1,3-diol.

[0025] The c- polyol preferably represents 1 to 20%, preferably 3 to 15%, and more preferably 5 to 10%, by weight relative to the total weight of the cosmetic composition.

[0026] In one embodiment, the cosmetic composition of the invention comprises: a- from 0.1 to 15%, preferably from 0.1 to 10%, and more preferably from 0.5 at 5%, by weight of alginate a-, b- from 0.5 to 15%, preferably from 0.5 to 10%, and more preferably from 1 to 8%, by weight of modified polysaccharide b-, and c- from 1 to 20%, preferably from 3 to 15%, and more preferably from 5 to 10%, by weight of polyol c- selected from diols, polyglycerols of formula H-(O-CH2-CH(OH)-CH2)n-OH in which n varies from 1 to 10, and their mixtures, relative to the total weight of the cosmetic composition.

[0027] The quantities of each of components a-, b-, and c- are preferably chosen so that the cosmetic composition provides a pleasant feel without being too sticky, while ensuring good adhesion to the skin. Thus, the proportions of each of components a-, b-, and c- are adjusted to achieve the desired compromise between stickiness and adhesion. Depending on the formula, for example, if it is a foundation or a serum, a compromise will be sought between adherence to the skin and the viscoelasticity of the composition. For example, if the formula contains powders, the amount of polyol to be introduced will be greater in order to maintain a certain degree of plasticity and elasticity.

[0028] The mass ratio of polyol c- / (alginate a- + modified polysaccharide b-) is preferably between 20 / 80 and 80 / 20, and preferably between 40 / 60 and 60 / 40.

[0029] According to a particularly advantageous embodiment, the cosmetic composition of the invention comprises a mixture capable of forming a film comprising: a- at least one alginate selected from sodium alginate (INCI name: ALGIN), b- at least one modified polysaccharide selected from hydroxypropyl starch (INCI name: HYDROXYPROPYL STARCH), and c- at least one polyol selected from a polyglycerol of formula H-(O-CH2- CH(OH)-CH2)n-OH in which n = 1 and / or 3.

[0030] In an advantageous embodiment, the cosmetic composition of the invention contains from 0.5 to 50%, preferably from 1 to 30%, and more Preferably, 5 to 25% by weight relative to the total weight of the cosmetic composition, of a mixture capable of forming an elastic film, consisting of α-alginate, β-modified polysaccharide, and β-polyol, as defined above. The mixture of α-alginate, β-modified polysaccharide, and β-polyol, as defined above, is also called a mixture of active ingredients.

[0031] The cosmetic composition of the invention may also include an aqueous phase, which may include water. Preferably, the composition comprises 40 to 99%, preferably 50 to 90%, and more preferably 60 to 70%, by weight of water, relative to the total weight of the cosmetic composition.

[0032] According to one embodiment of the invention, the cosmetic composition may further comprise at least one cosmetic active ingredient. The cosmetic active ingredient may, in particular, advantageously be chosen from among a moisturizing agent, an anti-wrinkle agent, an antioxidant, a free radical scavenger, an agent that repairs the damaging effects of ultraviolet rays, or a slimming agent such as caffeine. Preferably, the cosmetic active ingredient is chosen from among hyaluronic acids, such as sodium hyaluronate. The invention thus relates, in one of its aspects, to a cosmetic composition containing water and at least one cosmetic active ingredient in a proportion ranging from 0.01 to 5% by weight, relative to the total weight of the cosmetic composition.

[0033] The cosmetic composition of the invention may further comprise a gelling agent. Advantageously, natural or synthetic polysaccharides may be used as gelling agents, preferably selected from xanthan gum (such as Rhodicare® XC or T sold by Solvay Novecare or Keltrol® CG LAXT sold by CP Keltro), agar-agar (such as Ina Agar CS 83 sold by Iwase Cosfa), gellan gum (such as Kelcogel® CG-LA sold by Azelis), carrageenans (such as Satiagum™ VPC 430 sold by Cargill Beauty), cellulose and its derivatives such as hydroxyethylcellulose (such as Klucel® GF and Natrosol® 250 HHX, sold by Ashland) and hydroxypropylcellulose, corn starch, and cellulose carboxymethyl ethers. (such as Blanose™ 7H3SF sold by Ashland), bis-decyltetradeceth-20 ether-based copolymers (such as Adeka Nol GT-700 sold by Adeka), alkaligene polysaccharides (such as Alcasealan sold by Iwase Costa), Sclerotium gum (INCI name: Sclerotium Gum) (such as Amigel® sold by Alban Muller International (Croda)), and mixtures thereof. Synthetic polymers may also be advantageously mentioned, preferably selected from ammonium acryloyldimethyltaurate / VP copolymer (Aristoflex® AVC from Clariant International Ltd.), acrylate / C10-30 alkyl acrylate crosspolymer (Carbopol® Ultrez 21), or Polyacrylate Crosspolymer-6 (such as SEPIMAX ZEN™ sold by SEPPIC).The gelling agent is particularly advantageous when chosen from among xanthan gum (such as Rhodicare® XC or T sold by Solvay Novecare or Keltrol® CG LAXT sold by CP Keltro), gellan gum (such as Kelcogel® CG-LA sold by Azelis), hydroxyethylcellulose (such as Klucel® GF and Natrosol® 250 HHX sold by Ashland), alkaligene polysaccharides (such as Alcasealan sold by Iwase Cosfa), sclerotium gum (INCI name: Sclerotium Gum) (such as Amigel® sold by Alban Muller International (Croda)), acrylate / C10-30 alkyl acrylate crosspolymer (Carbopol® Ultrez 21), polyacrylate crosspolymer-6 (such as SEPIMAX ZEN™ sold by SEPPIC), and ammonium. acryloyldimethyltaurate / VP copolymer (Aristoflex® AVC of Clariant International Ltd.), and their mixtures.

[0034] The cosmetic composition of the invention may further include one or more cosmetic excipients such as opacifying agents, perfumes, reflective agents, coalescing agents, preservatives such as chlorphenesin (INCI name: CHLORPHENESIN), UVA and UVB ultraviolet protection agents, in particular filters, organic pigments and nano-pigments, such as zinc, iron and titanium oxides.

[0035] The cosmetic composition of the invention may be in the form of a gel, lotion, serum, suspension, oil-in-water emulsion, water-in-oil emulsion, or mask, and preferably in the form of a serum or an oil-in-water emulsion.

[0036] Another object of the invention relates to a method for preparing a cosmetic composition according to the invention, as described above.

[0037] The process for preparing the cosmetic composition of the invention comprises the following steps: (i) preparation of a mixture capable of forming an elastic film by dissolving in water: - at least one α-alginate or one of its derivatives, - at least one modified β- polysaccharide, and - at least one c- polyol selected from diols, polyglycerols of formula H-(O-CH2-CH(OH)-CH2)n-OH in which n varies from 1 to 10, and mixtures thereof, and (ii) dispersion of the mixture obtained in step (i) in an aqueous phase possibly including cosmetic active ingredients and / or excipients.

[0038] The components alginate a-, polysaccharide b- and polyol c-, used in the process of preparing the cosmetic composition of the invention are as defined above.

[0039] Advantageously, step (i) is carried out, under stirring, at a temperature ranging from 50 to 120°C, and preferably from 70 to 100°C, for a period ranging from 5 minutes to 1 hour, and preferably for about 30 minutes. The mixture obtained at the end of step (i) is then cooled to room temperature (20°C).

[0040] In step (i), the elastic mixture can be prepared by first dissolving the c- polyol in water. The a- alginate is then dissolved or dispersed in the water-c- polyol mixture, possibly with the addition of heat and stirring. Once the a- alginate has dissolved or dispersed, the b- modified polysaccharide is added, with heat added to thoroughly homogenize the different components. Advantageously, the a- alginate and the b- modified polysaccharide are added successively, with stirring, at a temperature of 50 to 120°C, and preferably 70 to 100°C, for a period of 5 minutes to 1 hour, and preferably for about 30 minutes. minutes. The mixture obtained at the end of step (i) is then cooled to room temperature (20°C).

[0041] In step (ii), the mixture prepared in step (i) is added to an aqueous phase comprising cosmetic actives and / or other cosmetic excipients.

[0042] According to another embodiment, the cosmetic composition of the invention is prepared by successively adding each of the components alginate a-, modified polysaccharide b-, and polyol c-, directly into the aqueous phase of the cosmetic composition, without prior mixing. Advantageously, the components alginate a-, modified polysaccharide b-, and polyol c- are added successively, with stirring, at a temperature ranging from 50 to 120°C, and preferably from 70 to 100°C, for a period ranging from 5 minutes to 1 hour, and preferably for approximately 30 minutes. The mixture obtained at the end of step (i) is then cooled to room temperature (20°C).

[0043] In the particular case of an emulsion, the components alginate a-, modified polysaccharide b-, and polyol c-, are added to the aqueous dispersing phase before dispersion of the oily phase.

[0044] Finally, a last object of the invention relates to a skin care process comprising a step of applying a cosmetic composition as defined according to the invention, on at least one part of the body and / or face, for a firming and smoothing effect.

[0045] In one embodiment, the application step on at least one part of the body and / or face is carried out on at least one area of ​​skin, in particular of the face and / or décolleté, showing signs of aging or fatigue such as loss of firmness, loss of elasticity, or sagging skin, to obtain an effect chosen from a smoothing effect, a tightening effect, a skin-bouncing effect, or a combination of one of these effects.

[0046] The cosmetic composition, when applied directly to the skin, forms, after application and gradual evaporation of the water in the composition, a film that exhibits elastic-type mechanical properties with a texture that... It is particularly well-suited to makeup. Furthermore, this type of texture possesses properties that are useful both aesthetically and in terms of user comfort, especially near highly mobile areas such as the eyes and lips. The elastic properties of the cosmetic composition of the invention are particularly useful for application to areas of the body subject to significant movement, such as facial skin.

[0047] The skin care process may include the topical application to the affected areas of skin of an effective amount of a cosmetic composition according to the invention as defined above, to obtain a second-skin sensation.

[0048] In addition to the foregoing provisions, the invention includes further provisions which will become apparent from the following supplementary description, relating to the preparation of cosmetic compositions according to the invention and comparative cosmetic compositions. Examples:

[0050] In the examples that follow, and unless otherwise indicated, all percentages are given as mass percentages, ingredients are designated by their INCI name, and the temperature is given in degrees Celsius.

[0051] Method for characterizing the smoothing effect: The test consists of evaluating and comparing the smoothing and tightening effect on the area at the corner of the eye known as "crow's feet" after 4 hours on a panel of four volunteers. The elastic mixture was applied to the crow's foot and then left to dry for 15 minutes. Visual observations were made immediately after drying and after 4 hours. Evaluation criteria: +++ means that the product has a very significant smoothing / tightening effect on crow's feet. ++ means that the product has a significant smoothing / tightening effect on crow's feet, + means that the product has a slightly visible smoothing effect on crow's feet, and x means that the product has no smoothing effect. Example 1:

[0052] Two compositions according to the invention (compositions 1 and 2) were prepared and compared to two comparative compositions (compositions 3 and 4) corresponding to the following formulas:

[0053] [Table 1]

[0054] The ingredients of phase A1 were weighed into a beaker and then mixed using a deflocculating turbine in a water bath at 85°C. Phase A2 was weighed, added to phase A1, and mixed for 30 minutes at 600 rpm. Phase A3 was weighed, added to phase A1, and mixed at 600 rpm for 30 minutes. The mixture was removed from the water bath and cooled to room temperature.

[0055] The smoothing effect of these four compositions was characterized. The results obtained are summarized in Table 2 below:

[0056] [Table 2]

[0057] Compositions 1 and 2 of the invention, comprising an alginate, a modified polysaccharide, and respectively, as a polyol, POLYGLYCERIN-3 (PGL-S) or VEGETABLE GLYCEROL, exhibit a very good immediate and long-term (4-hour) smoothing effect. Composition 1, based on POLYGLYCERIN-3 (PGL-S), even demonstrates an improved smoothing effect compared to Composition 2, based on VEGETABLE GLYCEROL.

[0058] On the contrary, comparative composition 3, combining an alginate, an unmodified polysaccharide (TAPIOCA NATURAL), and a polyol, presents an immediate smoothing effect but one that does not last over time.

[0059] Similarly, the comparative composition 4, combining alginate, a modified polysaccharide, and polyethylene glycol (PEG 6000), exhibits a slight, immediate smoothing effect that does not last. The film becomes rigid and brittle. Example 2: Anti-wrinkle serum according to the invention

[0060] An anti-wrinkle serum according to the invention, corresponding to the composition of Table 3 below, has been prepared.

[0061] [Table 3]

[0062] The ingredients of phase A were weighed successively into a beaker, then mixed using a deflocculating turbine in a water bath at 85°C. Once the mixture was homogeneous, it was removed from the water bath. The ingredients of phase B were weighed and then added to phase A at 70°C. The ingredients of phase C were weighed and then added to the previous phase at 50°C. The mixture was then blended until it reached room temperature. Example 3:

[0063] Three compositions (compositions 5, 6 and 7) conforming to the following formulas were prepared and compared:

[0064] [Table 4] Beauté By Roquette® ST 730: HYDROXYPROPYL STARCH with a molecular weight of 10 8 has 10 9 g.mol' 1Beauté By Roquette® ST 720: HYDROXYPROPYL STARCH with a molecular weight of 10 6 at 10 7 g. mol -1 Beauté By Roquette® ST 320: HYDROXYPROPYL STARCH PHOSPHATE

[0065] The ingredients of phase A1 were weighed into a beaker and then mixed using a deflocculating turbine in a water bath at 85°C. Phase A2 was weighed, added to phase A1, and mixed for 30 minutes at 600 rpm. Phase A3 was weighed, added to phase A1, and mixed at 600 rpm for 30 minutes. The mixture was removed from the water bath and cooled to room temperature.

[0066] The smoothing effect of these four compositions was characterized. The results obtained are summarized in Table 5 below:

[0067] [Table 5]

[0068] Compositions 5 and 6 have a comparable immediate smoothing effect (at 15 min), but this smoothing effect is less long-lasting for composition 6.

[0069] Compositions 5 and 6 exhibit a superior immediate smoothing effect (at 15 minutes) compared to composition 7, which is based on hydroxypropyl starch phosphate. Composition 5 also demonstrates a superior smoothing effect at 4 hours compared to composition 7, which is based on hydroxypropyl starch phosphate.

Claims

Demands

1. Cosmetic composition characterized in that it comprises a mixture capable of forming an elastic film comprising: a- at least one alginate, an alginate derivative, or mixtures thereof, b- at least one modified polysaccharide, and c- at least one polyol selected from diols, polyglycerols of formula H-(O-CH2-CH(OH)-CH2)n-OH in which n varies from 1 to 10, and mixtures thereof.

2. Composition according to claim 1, characterized in alginate a- is sodium alginate (INCI name: ALGIN).

3. Composition according to claim 1 or claim 2, characterized in that the modified polysaccharide b- is a modified starch, selected from alkylated starches, hydroxyalkylated starches, acetylated starches, and mixtures thereof, and preferably hydroxyalkylated starches.

4. Composition according to claim 3, characterized in that the modified b- polysaccharide is hydroxypropyl starch (HYDROXYPROPYL STARCH).

5. Composition according to claim 4, characterized in that the hydroxypropyl starch (INCI name: HYDROXYPROPYL STARCH) has a weight-average molecular weight greater than or equal to 10 6 g. mol 1 , and preferably 10 6 at 10 9 g. mol -1 .

6. Composition according to claim 5, characterized in that the hydroxypropyl starch (INCI name: HYDROXYPROPYL STARCH) has a weight average molecular weight of 10 8 at 10 9 g. mol 1 .

7. Composition according to any one of claims 1 to 6, characterized in that the c- polyol is a polyglycerol of formula H-(O-CH2- CH(OH)-CH2)n-OH in which n varies from 1 to 10, and preferably from 1 to 6.

8. Composition according to claim 7, characterized in that the c- polyol is a polyglycerol of formula H-(O-CH2-CH(OH)-CH2)n-OH in which n = 1, n = 3 or n = 6, and preferably a polyglycerol of formula H-(O-CH2-CH(OH)-CH2)n-OH in which n = 1 or n = 3.

9. Composition according to any one of claims 1 to 6, characterized in that the c- polyol is a diol selected from the aliphatic or aromatic, linear or branched C2-C12 diols, preferably propane-1,2-diol, propane-1,3-diol, butane-1,2-diol, butane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, octane-1,8-diol, and mixtures thereof, and more preferably propane-1,3-diol.

10. Composition according to any one of claims 1 to 9, characterized in that it comprises a mixture capable of forming a film comprising: a- at least one alginate selected from sodium alginate (INCI name: ALGIN), b- at least one modified polysaccharide selected from hydroxypropyl starch (INCI name: HYDROXYPROPYL STARCH), and c- at least one polyol selected from a polyglycerol of formula H-(O-CH2- CH(OH)-CH2)n-OH in which n = 1 and / or 3.

11. Composition according to any one of claims 1 to 10, characterized in that it comprises from 0.1 to 15%, preferably from 0.1 to 10%, and more preferably from 0.5 to 5%, by weight of an alginate α- relative to the total weight of the cosmetic composition.

12. Composition according to any one of claims 1 to 11, characterized in that it comprises from 0.5 to 15%, preferably from 0.5 to 10%, and more preferably from 1 to 8%, by weight of b-modified polysaccharide relative to the total weight of the cosmetic composition.

13. Composition according to any one of claims 1 to 12, characterized in that it comprises from 1 to 20%, preferably from 3 to 15%, and more preferably from 5 to 10%, by weight of a c- polyol relative to the total weight of the cosmetic composition.

14. Composition according to any one of claims 1 to 13, characterized in that the weight ratio polyol c- / (alginate a- + modified polysaccharide b-) varies from 20 / 80 to 80 / 20, and preferably from 40 / 60 to 60 / 40.

15. Composition according to any one of claims 1 to 14 characterized in that the mixture of alginate a-, modified polysaccharide b- and polyol c- represents from 0.5 to 50%, preferably from 1 to 30%, and more preferably from 5 to 25%, by weight relative to the total weight of the cosmetic composition.

16. Composition according to any one of claims 1 to 15 characterized in that it is in the form of a gel, lotion, serum, suspension, oil-in-water emulsion, or mask, and preferably in the form of a serum or an oil-in-water emulsion.

17. A method for preparing a cosmetic composition according to any one of claims 1 to 16, characterized in that it comprises the following steps: (i) preparation of a mixture capable of forming a film by dissolving in water: - at least one α-alginate or one of its derivatives, - at least one modified β- polysaccharide, and - at least one c- polyol selected from diols, polyglycerols of formula H-(O-CH2-CH(OH)-CH2)n-OH in which n varies from 1 to 10, and mixtures thereof, and (ii) dispersion of the mixture obtained in step (i) in an aqueous phase possibly including cosmetic active ingredients and / or excipients.

18. A skin care method characterized in that it comprises a step of applying a composition as defined according to any one of claims 1 to 16, to at least one part of the body and / or face.

19. A method according to claim 18, characterized in that the application step on at least one part of the body and / or face is carried out on at least one area of ​​skin, in particular of the face and / or décolleté, showing signs of aging or fatigue such as a loss of firmness, loss of elasticity, or sagging skin, to obtain an effect chosen from a smoothing effect, a tightening effect, a skin bouncing effect, or a combination of one of these effects.

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