Cosmetic composition comprising a chitosan-based elastic mixture

Abstract

The invention relates to a composition which comprises a mixture capable of forming a flexible elastic film comprising a chitosan, or a salt or derivative thereof, a modified polysaccharide, and a polyol, and which provides a tightening effect and deforms elastically in order to follow the mechanical movements and deformations of the surface of the skin. The present invention likewise relates to a method for preparing a cosmetic composition according to the invention, and also 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 mixture based on chitosan Technical Field

[0001] 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 surface of the skin. The present invention also relates to a process for preparing a cosmetic composition according to the invention, as well as a skin care process comprising a step of applying a cosmetic composition according to the invention to the skin.

[0002] Giving a smoothing effect to cosmetic compositions is a technique mastered in cosmetology. For this, we can use active ingredients, which penetrate the skin, and which will have a lasting effect over the long term. Film-forming polymers are also used for a smoothing effect, and their instantaneous mechanical actions on the surface of the skin. These smoothing materials, however, have certain drawbacks. First of all, once the product is applied to the skin, it is often uncomfortable due to the rigidity of the films formed. This rigidity of the films makes them poorly stretchable and inelastic, and consequently leads to poor durability of cosmetic compositions which crack and crumble quickly.

[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 consisting of at least one gelling or thickening starch, at least one polyol and at least one polymer chosen from polyvinyl alcohols, vinylpyrrolidone polymers and copolymers and latexes. These compositions, however, 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 mixture of specific compounds capable of forming an elastic film having an immediate, visible and lasting smoothing effect. The film thus formed can deform reversibly, so that it resumes after deformation, for example after stretching, the state it had before the application of the mechanical stress provided, for example by deformation of the skin. The film formed by the cosmetic composition comprising said mixture has greater resistance to breakage, which makes it possible to maintain intact the mechanical properties of the film formed on the surface of the skin. Once incorporated into a cosmetic composition, the mixture capable of forming this elastic film has an improved combined tensing and elastic effect, capable of following the movements of the skin without cracking.The effect obtained is comparable to a sheathing effect, the cosmetic composition of the invention providing elasticity to the skin naturally stressed by deformations, such as changes in facial expression or contact with the hands or clothing. The inventors have thus succeeded in developing a cosmetic composition capable of combining performances that are difficult to combine, namely a tightening effect combined with an elastic effect, which resolves the tightening / elasticity paradox. The new cosmetic composition is capable of acting effectively to smooth the surface of the skin, in particular obtaining a partial or total erasure of wrinkles, including medium and deep wrinkles.

[0005] The cosmetic composition of the invention has remarkable properties of tightening and elastic effect on the skin, properties which are linked to the simultaneous presence of a chitosan, salt or derivative, of a modified polysaccharide, and of a polyol. The cosmetic composition thus obtained allows a visible and lasting smoothing of the surface of the skin with very great comfort of use. General description of the invention

[0006] The present invention relates firstly to a cosmetic composition which comprises a mixture capable of forming an elastic film comprising: a- at least one polysaccharide selected from chitosan, its salts and derivatives, and their mixtures, b- at least one modified polysaccharide different from polysaccharide a-, and their mixtures, and c- at least one polyol.

[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. In the description, we speak indifferently of an elastic mixture or of a mixture capable of forming an elastic film.

[0008] A polymer is said to be film-forming within the meaning of the invention if, after evaporation of the volatile materials present in the medium, the formation of a continuous and homogeneous film is observed. Intermolecular bonds, responsible for the mechanical properties, are then formed 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.

[0009] The elastic blend of the cosmetic composition of the invention comprises an α-polysaccharide, also called a contractile film-forming polymer, which provides an immediate smoothing / tightening (lifting) effect. This contractile effect occurs upon drying, with hydrogen bonds forming between the polymer chains to create a contraction.

[0010] The polysaccharide a- of the invention is advantageously an unmodified chitosan or a modified chitosan. The chitosans that can be used in the context of the invention may be fully or partially deacetylated chitins. The molecular mass of the chitosan used may vary from 20,000 to approximately 5,000,000 g. mol 1 , preferably from 100,000 to 700,000 g. mol 1 The degree of deacetylation of chitosan can preferably vary from 50 to 99%.

[0011] In a preferred embodiment, the polysaccharide a- is an unmodified chitosan or a modified chitosan selected from alkylated chitosans, hydroxyalkylated chitosans, carboxylated chitosans, acylated chitosans, quaternized chitosans, and mixtures thereof.

[0012] According to one embodiment, the cosmetic composition of the invention comprises from 0.1 to 15%, preferably from 0.5 to 10%, and more preferably from 1 to 5%, by weight of polysaccharide a- relative to the total weight of said cosmetic composition.

[0013] The unmodified chitosan is advantageously selected from chitosan of fungal origin (CHITOSAN FUNGAL) or crustacean origin, for example from crabs, lobsters, squid or shrimp. In a particularly preferred embodiment, the polysaccharide a- is fungal chitosan (CHITOSAN FUNGAL).

[0014] The elastic mixture of the cosmetic composition of the invention also comprises a b-modified polysaccharide, also called an elastic film-forming polymer, which provides an elastic effect (comfort) to the composition. The b-modified polysaccharide of the invention has the advantage of providing, when mixed with the other ingredients, an elastic dry film which is transparent and which remains transparent after undergoing mechanical deformation (stretching). In particular, the film formed on the skin retains its transparency under the effect of multiple mechanical stresses, so that it does not disturb over time the color of the deposit on the skin of the cosmetic composition into which the mixture has been introduced.

[0015] The modified polysaccharide b- different from the polysaccharide a- is advantageously a modified starch. The modified starches of the invention are obtained from native starches which have been chemically and / or physically and / or enzymatically modified to improve their elastic properties. The native starches can come from a wide variety of sources, such as, for example, starches of corn, wheat, rice, buckwheat, barley, oats, millet, rye, sorghum, cassava, potato, sweet potato, tapioca, banana, plantain, malanga, tara, chestnut, beans, peas, and preferably native starches of corn, wheat, rice, cassava, potato, tapioca, peas.

[0016] The modified starches used in the context of the invention have the advantage of providing, when mixed with the other components of the invention, elastic dry films which are transparent and which remain transparent after stretching(s) when they are prepared in the form of thin films (typically of thicknesses less than one millimeter). 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.

[0017] The modified polysaccharide b- advantageously has a weight-average molecular weight greater than 10 6 g. mol' 1 , and preferably 10 6 at 10 9 g. mol' 1 . The weight average molecular weight can be determined by HPSEC-MALLS (high performance size exclusion chromatography coupled online with multi-angle laser light scattering detection).

[0018] Among the preferred modified starches, mention may be made of alkylated starches, hydroxyalkylated starches, acetylated starches, starch hydrolysates, oxidized starches, phosphated starches, hydroxyalkylated, phosphated or acetylated distarch phosphates, and mixtures thereof. More particularly preferred starches are alkylated starches, hydroxyalkylated starches, acetylated starches, oxidized starches, phosphated starches, hydroxyalkylated, phosphated or acetylated distarch phosphates, and mixtures thereof, and even more preferably hydroxyalkylated starches.

[0019] The b-modified polysaccharide is advantageously selected from hydroxyalkylated starches. In a preferred embodiment, the b-modified polysaccharide is hydroxypropylated starch which may have the INCI name: HYDROXYPROPYL STARCH, such as the Beauté By Roquette® ST 720 product marketed by the company ROQUETTE.

[0020] In a particularly preferred embodiment, the modified polysaccharide b- is a hydroxyalkylated starch, and even more preferably a hydroxypropylated starch, having a weight average molecular weight greater than 10 6 g. mol' 1 , and advantageously 10 6 at 10 9 g. mol' 1 . The weight average molecular weight can be determined by HPSEC-MALLS.

[0021] The modified polysaccharide b- preferably represents from 1 to 15%, preferably from 2 to 10%, and more preferably from 4 to 8%, by weight relative to the total weight of the cosmetic composition.

[0022] The elastic mixture of the cosmetic composition of the invention also comprises 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, and making them more elastic and more flexible.

[0023] The polyol c- of the invention may be an alcohol having from 1 to 30 carbon atoms and 2 to 12 hydroxyl functions, and in particular an alcohol having from 2 to 10 carbon atoms and 2 to 4 hydroxyl functions. The polyol c- may also be a sugar such as glucose, sorbitol, mannitol. Advantageously, the polyol c- has a weight-average molecular weight which varies from 300 to 800 g. mol 1 .

[0024] The polyol c- is advantageously selected from diols, polyglycerols of formula H-(O-CH2-CH(OH)-CH2)n-OH in which n varies from 2 to 10, and preferably from 2 to 4, and mixtures thereof.

[0025] According to one embodiment, the polyol c- is a diol selected from linear or branched aliphatic or aromatic 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, more preferably propane-1,3-diol, butane-1,2-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, octane-1,8-diol, and mixtures thereof, and even more preferably propane-1,3-diol.

[0026] According to another embodiment, the polyol c- is a polyglycerol of formula H-(O-CH2-CH(OH)-CH2) n -OH in which n varies from 2 to 10.

[0027] According to a particularly advantageous embodiment, the polyol c- is a polyglycerol of formula H-(O-CH2-CH(OH)-CH2) n -OH in which n = 3 and / or 6 (POLYGLYCERIN-3 (PGL-S MB) and / or POLYGLYCERIN-6 (POLYGLYCERIN 500 MB), marketed for example by the company SAKAMOTO YAKUHIN KOGYO. More particularly, it is the polyglycerol of formula H-(O-CH2-CH(OH)- CH2) n -OH in which n = 3 (POLYGLYCERIN-3), marketed by the company SAKAMOTO YAKUHIN KOGYO under the reference PGL-S MB. Compared to other polyols, POLYGLYCERIN-3 allows a better level of plasticization of the polysaccharide a- and the modified polysaccharide b- on the surface of the skin.

[0028] The polyol c- preferably represents from 1 to 20%, preferably from 3 to 15%, and more preferably from 5 to 10%, by weight relative to the total weight of the cosmetic composition.

[0029] In one embodiment, the cosmetic composition of the invention comprises: a- from 0.1 to 15%, preferably from 0.5 to 10%, and more preferably from 1 to 5%, by weight of polysaccharide a-, b- from 1 to 15%, preferably from 2 to 10%, and more preferably from 4 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-, relative to the total weight of the cosmetic composition.

[0030] The quantities of each of the constituents a-, b- and c- are preferably chosen so that the cosmetic composition provides a pleasant sensation to the touch, without being too sticky, while ensuring good adhesion to the skin. Thus, the proportions of each of the constituents a-, b- and c- are adjusted to satisfy the desired compromise between stickiness and adhesion properties. Depending on the formulas, for example if it is a foundation or a serum, a compromise will be sought between adhesion to the skin and the viscoelasticity of the composition. For example, if the formula contains powders, the quantity of polyol to be introduced will be greater in order to maintain a certain plasticity and elasticity.

[0031] The mass ratio between the polyol c- and the two polysaccharides a- and b- is preferably between 20 / 80 and 80 / 20, and preferably from 40 / 60 to 60 / 40.

[0032] According to a particularly advantageous embodiment, the cosmetic composition of the invention comprises a mixture capable of forming an elastic film comprising: a- at least one polysaccharide selected from fungal chitosan (CHITOSAN FUNGAL), b- at least one modified polysaccharide selected from hydroxypropyl starch (HYDROXYPROPYL STARCH), and c- at least one polyol selected from polyglycerol of formula H-(O-CH2- CH(OH)-CH2) n -OH in which n = 3 and / or 6 (POLYGLYCERIN-3 and / or POLYGLYCERIN-6), advantageously in the preferred weight % indicated above.

[0033] In the mixture capable of forming an elastic film of the cosmetic composition of the invention, the polysaccharide a-, the modified polysaccharide b-, and the polyol c-, are preferably present in proportions such that the elasticity of the dry film (free of water), with a thickness of between 50 and 1,000 microns, obtained from said mixture is characterized by: - a loss of elasticity, measured after at least one pull, less than 20%, and - resilience of at least 50%.

[0034] The elasticity of the elastic mixture present in the cosmetic composition of the invention can be measured by a method well known to those skilled in the art, for example with a TA.XT Plus reference texturometer (Stable Micro Systems), by measuring the force exerted by a dry film obtained from the mixture and undergoing a tensile test at an imposed speed. The thickness of the film chosen to carry out this measurement is preferably between 50 and 1,000 microns, and more preferably between 200 and 400 microns.

[0035] Tensile testing involves applying two opposing forces to the sample. The ends of a film sample are clamped between two jaws of the tensile testing machine, one fixed and the other attached to a pneumatic piston. The sample is then subjected to uniaxial stretching at a set speed over a given distance. The forces are recorded by the force sensor located on the fixed part of the machine, and a diagram is plotted showing the force exerted by the sample as a function of the elongation of the film. the sample, as well as a diagram reproducing the force exerted by the sample as a function of time.

[0036] The residual strain rate is preferably measured after at least one tensile step, at a set distance equal to one third of the sample length, for example at a distance ranging from one third to four times its length. Successive stretching cycles can also be carried out by gradually increasing the stretching distance.

[0037] The quantity of elastic mixture introduced into the cosmetic composition of the invention is advantageously chosen according to the desired cosmetic effect and the desired viscosity. Indeed, the viscosity of the product must be compatible with regular, pleasant and sufficient application to the skin. The quantity of mixture capable of forming an elastic film is chosen in particular to allow the formation of an elastic film at the time of application of the cosmetic composition to the skin.

[0038] The proportions between the different components will be optimized to achieve the right viscoelasticity and good adhesion to the skin. Depending on the formula, for example if it is a foundation or a serum, a compromise will be sought between adhesion to the skin and the viscoelasticity of the cosmetic composition. For example, if the formula contains powders, the quantity of polyol to be introduced will be greater in order to maintain the plasticity and elasticity of the cosmetic composition.

[0039] In an advantageous embodiment, the cosmetic composition of the invention contains 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, of a mixture capable of forming an elastic film consisting of polysaccharide a-, modified polysaccharide b-, and polyol c-, as defined above.

[0040] The cosmetic composition of the invention may further comprise an aqueous phase, which may comprise water. Preferably, the composition comprises from 40 to 99%, preferably from 50 to 90%, and more preferably from 60 to 70%, by weight of water, relative to the total weight of the cosmetic composition.

[0041] According to a variant of the invention, the cosmetic composition may further comprise at least one cosmetic active ingredient. The cosmetic active ingredient may in particular be advantageously chosen from a moisturizing agent, an anti-wrinkle agent, an antioxidant agent, an anti-free radical agent, an agent for repairing the destructive effects of ultraviolet rays, or a slimming agent such as caffeine. Preferably, the cosmetic active ingredient is chosen from hyaluronic acids, such as sodium hyaluronate. The invention thus relates, according to 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.

[0042] The cosmetic composition of the invention may further comprise a gelling agent.As gelling agent, mention may advantageously be made of natural or synthetic polysaccharides, preferably chosen 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, cellulose carboxymethyl ethers (such as Blanose™ 7H3SF sold by Ashland), copolymers with bis-decyltetradeceth-20 ether base (such as Adeka Nol GT-700 sold by Adeka), Sclerotium gum (INCI name: Sclerotium Gum) (such as Amigel® sold by Alban Muller International (Croda)), and mixtures thereof.Synthetic polymers such as ammonium acryloyldimethyltaurate / VP copolymer (Aristoflex® AVC from Clariant International Ltd.) may also advantageously be mentioned. Particularly advantageously, the gelling agent is chosen from 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), Sclerotium gum (INCI name: Sclerotium Gum) (such as Amigel® sold by Alban Muller International (Croda)), ammonium acryloyldimethyltaurate / VP copolymer (Aristoflex® AVC from Clariant International Ltd.), and mixtures thereof.

[0043] The cosmetic composition of the invention may further comprise at least one pH adjusting agent. This pH adjusting agent is advantageously chosen from alkali hydroxides such as sodium hydroxide or ammonium hydroxide, triethanolamine, 2-amino-2-(hydroxymethyl)-1,3-propanediol, borates, phosphates, pyrophosphates, ascorbic acid and its salts such as trisodium citrate dihydrate, sorbic acid and its salts, phosphoric acid and its salts, citric acid and its salts, lactic acid and its salts, boric acid and its salts, acetic acid and its salts, preferably alkali hydroxides, and more preferably an alkali hydroxide such as sodium hydroxide. The pH adjusting agent is advantageously used in an amount capable of giving the cosmetic composition a pH ranging from 4 to 7.According to one embodiment, the pH adjusting agent is present in an amount ranging from 0.01 to 1% by weight relative to the total weight of the cosmetic composition.

[0044] The cosmetic composition of the invention may further comprise one or more cosmetic excipients such as opacifying agents, perfumes, reflective agents, coalescing agents, preservatives such as chlorphenesin (INCI name: CHLORPHENESIN), protective agents against UVA and UVB ultraviolet rays, in particular filters, organic pigments and nano-pigments, such as zinc, iron and titanium oxides.

[0045] The cosmetic composition of the invention may be in the form of a gel, a lotion, a serum, a suspension, an oil-in-water emulsion, a water-in-oil emulsion, or a mask, and preferably in the form of a serum or an oil-in-water emulsion.

[0046] Another subject of the invention relates to a process for preparing a cosmetic composition according to the invention, as described previously.

[0047] 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 at least one polysaccharide a-, at least one modified polysaccharide b-, and at least one polyol c-, in water, and (ii) dispersion of the mixture obtained in step (i) in an aqueous phase optionally comprising cosmetic active ingredients and / or excipients.

[0048] Advantageously, step (i) is carried out, 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).

[0049] In step (i), the elastic mixture can be prepared by first dissolving the polyol c- in water. The polysaccharide a- is then dissolved or dispersed in the mixture based on water and polyol c-, with the optional addition of heat and stirring. Once the polysaccharide a- is dissolved or dispersed, the modified polysaccharide b- is then added, with the addition of heat to thoroughly homogenize the various constituents. Advantageously, the polysaccharide a- and the modified polysaccharide b- 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).

[0050] In step (ii), the mixture prepared in step (i) is added to an aqueous phase comprising cosmetic active ingredients and / or other cosmetic excipients.

[0051] According to another embodiment, the cosmetic composition of the invention is prepared by successively adding each of the components polysaccharide a-, modified polysaccharide b-, and polyol c-, directly into the aqueous phase of the cosmetic composition, without prior mixing. Advantageously, the components polysaccharide 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).

[0052] In the particular case of an emulsion, the components polysaccharide a-, modified polysaccharide b-, and polyol c- are added to the dispersing aqueous phase before dispersion of the fatty phase.

[0053] Finally, a final object of the invention relates to a skin care method comprising a step of applying a cosmetic composition as defined according to the invention, to at least one part of the body and / or the face.

[0054] In one embodiment, the step of application to at least one part of the body and / or face is carried out on at least one area of ​​skin, in particular the face and / or décolleté, showing signs of aging or fatigue such as a loss of firmness, a loss of elasticity, or sagging skin, to obtain an effect chosen from a smoothing effect, a tightening effect, a skin plumping effect, or a combination of one of these effects.

[0055] The cosmetic composition directly applied to the skin forms, after application and gradual evaporation of the water in the composition, a film which has elastic-type mechanical properties with a texture which is particularly well suited to makeup. In addition, this type of texture has useful properties both in terms of aesthetics and comfort of use, particularly 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 the skin of the face.

[0056] The skin care method may comprise the topical application to the areas of the skin concerned of an effective amount of a cosmetic composition according to the invention as defined above, to obtain a second skin sensation.

[0057] In addition to the preceding provisions, the invention also comprises other provisions which will emerge from the additional description which follows, which relates to the preparation of cosmetic compositions according to the invention and comparative cosmetic compositions.

[0058] Examples:

[0059] In the following examples, and unless otherwise indicated, all percentages are given in mass percentages, the ingredients are designated by their INCI name, and the temperature is indicated in degrees Celsius.

[0060] Methods for characterizing elastic films: - Elastic properties (fatigue resistance): Fatigue resistance was assessed using a TA.XT Plus texturometer (Stable Micro Systems). The prepared elastic films were cast into Teflon® molds and then dried at 33°C under 50% relative humidity, to achieve a thickness of 200 to 400 μm dry. 5 x 3 cm specimens were then cut and subjected to repeated stretching: 25 cycles of 50% stretching back and forth at 1 mm / second. Elastic properties (fatigue resistance) were ranked from most elastic (+++) to least elastic (+). - Evaluation of the contractile effect on nitrile support: The contractile effect of the elastic films was evaluated visually at room temperature (20°C). A nitrile glove cut into a 3 x 5 cm test piece was used as a support. The elastic mixtures were spread with a spatula on the nitrile support in order to obtain a dry film mass of 0.05 g, which corresponds to a dry film thickness (or remaining dry mass) of 33 μm, then left to dry for 24 hours at room temperature (20°C). During the drying of elastic films, they shrink more or less and are classified into three categories: Category 1: the support is not retracted, the film does not show any contractile effect, Category 2: the support has slightly retracted compared to the start of the test, a contractile effect is visible, Category 3: the support has retracted and rolled up on itself, the contractile effect is significant. - Method for characterizing the smoothing effect in vivo at 1 hour and 4 hours: The aim of the test was to evaluate and compare the smoothing effect on the area of ​​the corner of the eye called "crow's feet" after 1 hour and 4 hours on a panel of 10 volunteers. All measurements were carried out at a temperature of 22°C and 50% relative humidity. 1- Taking a fingerprint A first impression was taken before applying the cosmetic composition under evaluation. To make the impression, a film-forming resin was spread using a spatula on the area under study. After drying, the replica of the skin area was peeled off. The product was applied to the crow's feet in an amount of 2 mg.cnT 2 , left to dry for 15 minutes, then measurements were taken after 1 hour and 4 hours. A second impression was taken 1 hour, then 4 hours, after application of the cosmetic composition. The same protocol was reproduced for each cosmetic composition studied. 2- Image analysis Each replica was positioned on a support and illuminated using a grazing illuminator with an angle of incidence of 35°, in order to generate shadows behind each line of the skin surface. These shadows were then analyzed on high-resolution images of the replica to obtain numerical values ​​of the gray levels of each analyzed pixel. Device used: The QUANTIRIDES® software calculates the following parameters: number of wrinkles, total surface area of ​​wrinkles in mm 2 , total wrinkle length in mm, average wrinkle length in mm, average wrinkle depth in pm. The smoothing effect was evaluated by comparing these parameters before and after application of the cosmetic composition (1 hour and 4 hours after application). The greater the reduction in wrinkle areas, their length and / or their surface or depth, the more significant the smoothing effect observed. Evaluation criteria: +++ means that the product has a very significant smoothing effect on crow's feet, 1 or 4 hours after application, ++ means that the product has a significant smoothing effect on crow's feet, 1 or 4 hours after application, and + means that the product has little smoothing effect on crow's feet, 1 or 4 hours after application. [00611 Example 1: Preparation and characterization of mixtures

[0062] Two elastic mixtures A and B according to the invention and a mixture C outside the invention corresponding to the formulas in Table 1 were prepared:

[0063] [Table 1]

[0064] Three aqueous dispersions each comprising one of the mixtures A, B and C were prepared according to the formula in Table 2 below:

[0065] [Table 2]

[0066] Purified water, sodium hydroxide, and polyol c- were weighed into a beaker and mixed using a deflocculating turbine at 150 rpm in a water bath at 80°C. Polysaccharide a- was weighed into a dish and then incorporated into the beaker in a fine spray while stirring at 400 rpm. Once the mixture was homogeneous, polysaccharide b- was weighed into a dish and then incorporated into the beaker while stirring at 600 rpm. Once the mixture was homogeneous, the prepared mixture was removed from the water bath and cooled to room temperature while stirring at 300-400 rpm. The prepared mixtures were then used to form elastic films, which were evaluated.

[0067] The measured characteristics for elastic mixtures A, B and C are summarized in the following Table 3:

[0068] [Table 3]

[0069] The elastic mixtures A and B comprising the three components a-, b- and c- are those which allow the best compromise between tensor effect and elastic effect to be obtained.

[0070] Example 2: Preparation and characterization of mixtures

[0071] Two elastic mixtures D and E corresponding to the formulas in Table 4 were evaluated:

[0072] [Table 4]

[0073] Two aqueous dispersions each comprising one of the mixtures D and E were prepared according to the formula in Table 5 below:

[0074] [Table 5]

[0075] Purified water, sodium hydroxide, chlorphenesin and polyol c- were weighed into a beaker and then mixed using a deflocculating turbine, at water bath at 75°C. The polysaccharide a- was weighed into a dish and then incorporated into the beaker in a fine spray, while stirring at 600 rpm. Once the mixture was homogeneous, the polysaccharide b- was weighed into a dish and then incorporated into the beaker, while stirring at 600 rpm. Once the mixture was homogeneous, the prepared mixture was removed from the water bath and cooled to room temperature. The prepared mixtures were then used to form elastic films, which were evaluated.

[0076] The measured characteristics for elastic mixtures D and E are summarized in the following Table 6:

[0077] [Table 6]

[0078] Elastic mixture D based on HYDROXYPROPYL STARCH provides a better compromise between tightening effect and elastic effect than elastic mixture E. Elastic mixture E based on HYDROGENATED STARCH HYDROLYSATE produces an elastic film, but does not have an immediate and lasting smoothing effect.

[0079] Example 3: Serum according to the invention A serum composition according to the invention corresponding to the formula in Table 7 was prepared according to the following protocol:

[0080] [Table 7]

[0081] The ingredients of phase Al were weighed into a beaker and mixed under slow stirring using a deflocculating turbine in a water bath at 80°C. Phase A2 was weighed and added to phase Al. Phase B was weighed, emulsified in phase A, and mixed at 600 rpm. Phase Cl was weighed and slowly stirred using a deflocculating turbine in a water bath at 80°C. Phase C2 was weighed into a dish and added in a fine rain to Cl. Phase C3 was weighed into a dish and added in a fine rain to phases Cl and C2. All of phase C was emulsified with phase A in a water bath at 80°C. The temperature was then cooled to room temperature. Phase D was weighed into a dish and added to the beaker. Phases E and F were weighed into capsules and then added to the beaker.

[0082] The mixture thus prepared allowed the formation of an elastic film, presenting the following properties:

[0083] [Table 8]

[0084] Example 4: Eye contour cream according to the invention An eye contour cream composition according to the invention corresponding to the formula in Table 9 was prepared according to the following protocol:

[0085] [Table 9]

[0086] The ingredients of phase A were weighed into a beaker and mixed under stirring using a deflocculating turbine in a water bath at 85°C. Phase B1 was weighed into a beaker and mixed under stirring using a deflocculating turbine in a water bath at 85°C. Phase B2 was weighed into a dish and added to phase B1 in a fine rain shower and mixed under stirring at 300 rpm for 20 minutes. Phase B3 was weighed and added to phases B1 and B2 in a fine rain shower and mixed under stirring at 600 rpm for 30 minutes. All of phase B was de-bubbled by reducing stirring to 200 rpm. Phase B was emulsified in phase A by slowly pouring phase B into phase A in a water bath at 85°C and gradually increasing the stirring speed to 800 rpm. The mixture was stirred at at this speed for 10 minutes, then removed from the water bath. Phase C was weighed into a dish and then added to the beaker at a temperature of 50°C. Phase D was weighed and then added to the beaker at a temperature below 40°C.

[0087] The mixture thus prepared allowed the formation of an elastic film, presenting the following properties:

[0088] [Table 10]

[0089] Example 5: Serum according to the invention and comparative serum A serum composition according to the invention corresponding to the formula of Table 11 was prepared according to the following protocol:

[0090] [Table 11]

[0091] The ingredients of phase A were weighed into a beaker and mixed under slow stirring using a deflocculating turbine in a water bath at 80°C. Phase B was weighed into a dish and emulsified in phase A by increasing the stirring speed to 600 rpm. Phase Cl was weighed into a beaker and mixed under slow stirring using a deflocculating turbine in a water bath at 80°C. Phase C2 was weighed into a dish and added to phase Cl in a fine rain. Phase C3 was weighed into a dish and added to phases Cl and C2 in a fine rain. All of phase C was emulsified in phase A at a temperature of 80°C and then brought back to room temperature. Phase D was weighed into a dish and added to the beaker. Phases E and F were weighed into capsules and then added to the beaker.

[0092] The mixture thus prepared allowed the formation of an elastic film, presenting the following properties:

[0093] [Table 12]

[0094] A serum formula similar to that in Table 11, but without modified polysaccharide b-(HYDROXYPROPYL STARCH) was prepared using the same procedure as before. The film formed was uncomfortable because it was too tight, and then cracked due to lack of elasticity.

[0095] The mixture thus prepared allowed the formation of a film, presenting the following properties:

[0096] [Table 13]

[0097] Example 6: Eye contour cream according to the invention and comparative cream An eye contour cream composition according to the invention corresponding to the formula in Table 14 was prepared according to the following protocol:

[0098] [Table 14]

[0099] The ingredients of phase A were weighed into a beaker and then mixed under stirring using a deflocculating turbine in a water bath at 85°C. Phase B1 was weighed into a beaker and mixed with stirring using a deflocculating turbine in a water bath at 85°C. Phase B2 was weighed into a dish and added to phase B1 in a fine spray, then mixed with stirring at 300 rpm for 20 minutes. Once phase B was homogenized, phase B3 was weighed and then added to phases B1 and B2. All of phase B was de-bubbled by reducing stirring to 200 rpm. Phase B was emulsified in phase A by slowly pouring phase B into phase A in a water bath at 85°C and gradually increasing the stirring speed to 800 rpm. The mixture was stirred at this speed for 10 minutes and then removed from the water bath. Phase C was weighed into a dish and then added to the beaker at a temperature of 50°C. Phases D and E were weighed and then added to the beaker at a temperature below 40°C.

[0100] The mixture thus prepared allowed the formation of an elastic film, presenting the following properties:

[0101] [Table 15]

[0102] A cream formula similar to that of Example 6, but free of modified polysaccharide b-(HYDROXYPROPYL STARCH) was prepared using the same procedure as above. The film formed proved uncomfortable because it was too tight, and then cracked due to a lack of elasticity.

[0103] The mixture thus prepared allowed the formation of a film, presenting the following properties:

[0104] [Table 16] r0105~l Example 7: Creams according to the invention Two cream compositions according to the invention corresponding to the formulas in Table 17 were prepared according to the following protocol:

[0106] [Table 17]

[0107] The ingredients of phase A were weighed into a beaker and then mixed under stirring using a deflocculating turbine in a water bath at 85°C. Phase B1 was weighed into a beaker and then mixed under stirring using a deflocculating turbine in a water bath at 85°C. Phase B2 was weighed into a dish and added to phase B1 in a fine rain, then mixed under stirring at 300 rpm for 30 minutes at 85°C. Phase B3 was weighed into a capsule, then added to phases B1 and B2 in fine rain, and mixed under stirring at 300 rpm for 30 minutes at 85°C. All of phase B was de-bubbled, reducing stirring to 200 rpm. Phase B was emulsified in phase A in a water bath at 85°C, mixed for 10 minutes, then removed from the water bath. Phase C was weighed into a capsule, mixed using a spatula, then added to phase B1 in fine rain, and finally mixed under stirring at 300 rpm for 30 minutes at 85°C. Phase D was weighed, then added to the beaker, at a temperature below 40°C.

[0108] The mixtures thus prepared allowed the formation of elastic films, presenting the following properties:

[0109] [Table 18] [OllOlExemole 8: Fluid foundation according to the invention A fluid foundation composition according to the invention corresponding to the formula in Table 19 was prepared according to the following protocol: [YES] [Table 19]

[0112] The ingredients of phase Al were weighed into a beaker and mixed under stirring using a deflocculating turbine at room temperature. Phase A2 was weighed into a dish, dispersed in phase Al, and mixed under stirring using a deflocculating turbine at 150 rpm. Phase B1 was weighed into a beaker and mixed under stirring using a deflocculating turbine in a water bath at 80°C. Phase B2 was weighed into a dish and added to phase B1 in a fine rain. Phase B3 was weighed into a dish and added to phases B1 and B2 in a fine rain. The mixture was then cooled to room temperature. Phases B4 and B5 were then added. All of phase B was emulsified in phase A, then mixed under agitation using a deflocculating turbine at 1000 rpm for 5 minutes, then at 800 rpm for 30 minutes.

[0113] After application, the foundation produces a smoothing effect on the user's skin, without any feeling of tightness during the day.

Claims

Claims 1. Cosmetic composition characterized in that it comprises a mixture capable of forming an elastic film comprising: a- at least one polysaccharide selected from chitosan, its salts and derivatives, and their mixtures, b- at least one modified polysaccharide different from polysaccharide a-, and their mixtures, and c- at least one polyol.

2. Composition according to claim 1, characterized in that the polysaccharide a- is an unmodified chitosan or a modified chitosan selected from alkylated chitosans, hydroxyalkylated chitosans, carboxylated chitosans, acylated chitosans, quaternized chitosans, and mixtures thereof.

3. Composition according to claim 1 or claim 2, characterized in that the polysaccharide a- is an unmodified chitosan selected from fungal chitosan (CHITOSAN FUNGAL), crustacean chitosan, and their mixture, and preferably fungal chitosan (CHITOSAN FUNGAL).

4. Composition according to one of claims 1 to 3, characterized in that the modified polysaccharide b- is a modified starch, preferably selected from alkylated starches, hydroxyalkylated starches, acetylated starches, starch hydrolysates, oxidized starches, phosphated starches, hydroxyalkylated, phosphated or acetylated distarch phosphates, and mixtures thereof, more preferably selected from alkylated starches, hydroxyalkylated starches, acetylated starches, starch hydrolysates, oxidized starches, phosphated starches, hydroxyalkylated, phosphated or acetylated distarch phosphates, and mixtures thereof, and even more preferably hydroxyalkylated starches.

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

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

7. Composition according to one of claims 1 to 6, characterized in that the polyol c- is selected from diols, polyglycerols of formula H-(O-CH2- CH(OH)-CH2) n -OH in which n varies from 2 to 10, and preferably from 2 to 4, and mixtures thereof.

8. Composition according to one of claims 1 to 7, characterized in that the polyol c- is a diol selected from C2-Ci2 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, more preferably propane-1,3-diol, butane-1,2-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, octane-1,8-diol, and mixtures thereof, and even more preferably propane-l,3-diol.

9. Composition according to one of claims 1 to 8, characterized in that the polyol c- is a polyglycerol of formula H-(O-CH2-CH(OH)-CH2) n -OH in which n varies from 2 to 10, and preferably from 2 to 4, the polyol c- preferably being a polyglycerol of formula H-(O-CH2-CH(OH)-CH2) n -OH in which n = 3 and / or 6 (POLYGLYCERIN-3 and / or POLYGLYCERIN-6).

10. Composition according to one of claims 1 to 9, characterized in that it comprises a mixture capable of forming a film comprising: a- at least one polysaccharide selected from fungal chitosan (CHITOSAN FUNGAL), b- at least one modified polysaccharide selected from hydroxypropyl starch (HYDROXYPROPYL STARCH), and c- at least one polyol selected from polyglycerol of formula H-(O-CH2- CH(OH)-CH2) n -OH in which n = 3 and / or 6 (POLYGLYCERIN-3 and / or POLYGLYCERIN-6).

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

12. Composition according to one of claims 1 to 11, characterized in that it comprises from 1 to 15%, preferably from 2 to 10%, and more preferably from 4 to 8%, by weight of modified polysaccharide b- relative to the total weight of the cosmetic composition.

13. Composition according to 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 polyol c- relative to the total weight of the cosmetic composition.

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

15. Composition according to one of claims 1 to 14, characterized in that the mixture of polysaccharide 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 one of claims 1 to 15, characterized in that it comprises water, preferably in an amount ranging from 40 to 99%, preferably from 50 to 90%, and more preferably from 60 to 70%, by weight relative to the total weight of the cosmetic composition.

17. Composition according to one of claims 1 to 16, characterized in that it comprises a pH adjusting agent, preferably an alkali hydroxide such as sodium hydroxide, and more preferably in an amount ranging from 0.01 to 1% by weight relative to the total weight of the cosmetic composition.

18. Composition according to one of claims 1 to 17, characterized in that it is in the form of a gel, a lotion, a serum, a suspension, an oil-in-water emulsion, or a mask, and preferably in the form of a serum or an oil-in-water emulsion.

19. Process for preparing a cosmetic composition according to one of claims 1 to 18, characterized in that it comprises the following steps: (i) preparing a mixture capable of forming a film by dissolving at least one polysaccharide a-, at least one modified polysaccharide b-, and at least one polyol c-, in water, and (ii) dispersion of the mixture obtained in step (i) in an aqueous phase optionally comprising cosmetic active ingredients and / or excipients.

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

21. Method according to claim 20, characterized in that the step of application to at least one part of the body and / or face is carried out on at least one area of ​​skin, in particular the face and / or décolleté, showing signs of aging or fatigue such as a loss of firmness, a loss of elasticity, or sagging skin, to obtain an effect chosen from a smoothing effect, a tightening effect, a skin plumping effect, or a combination of one of these effects.

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