Cosmetic composition comprising an elastic mixture based on natural starch, polyurethane and polyol

Abstract

Cosmetic composition comprising an elastic mixture based on natural starch, polyurethane, and polyol. The invention relates to a composition comprising a mixture capable of forming a flexible elastic film comprising: at least one natural starch, at least one polyurethane, and at least one polyol selected from diols, polyglycerols of the formula H-(O-CH2-CH(OH)-CH2)n-OH in which n varies from 2 to 10, and mixtures thereof, 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.

Description

Title of the invention: Cosmetic composition comprising an elastic mixture based on natural starch, polyurethane and polyol 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 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 compositions a smoothing effect is a well-established technique in cosmetology. This can be achieved using active ingredients that penetrate the skin and have a long-lasting effect. Film-forming polymers are also used for a smoothing effect, providing immediate mechanical action on the skin's surface. However, these smoothing materials have some drawbacks. First, once the product is applied to the skin, it is often uncomfortable due to the rigidity of the films formed. This rigidity makes the films difficult to stretch and inelastic, consequently leading to poor durability of the 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 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 mixture 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 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 the mechanical properties of the film formed on the skin surface intact. Once incorporated In a cosmetic composition, the mixture capable of forming this elastic film has a combined tightening and enhanced elastic effect, able to follow the skin's movements without cracking. The resulting effect is comparable to a sheathing effect, the cosmetic composition of the invention providing 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 performances that are difficult to reconcile, namely a tightening effect combined with an elastic effect, which resolves 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 elastic properties, which are linked to the simultaneous presence of a natural starch, a polyurethane, and a polyol. The resulting cosmetic composition provides a visible and lasting smoothing of the skin's surface with exceptional user comfort.

[0006] General description of the invention

[0007] The present invention relates first to a cosmetic composition comprising a mixture capable of forming an elastic film comprising: a- at least one natural starch, b- at least one polyurethane, 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 2 to 10, and their mixtures.

[0008] 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, the terms "elastic mixture" and "mixture capable of forming an elastic film" are used interchangeably.

[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 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 elastic blend of the cosmetic composition of the invention comprises a natural α-starch, also called 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.

[0011] The natural starch a- of the invention has not undergone any chemical transformation; it corresponds to the matter as found in nature. The natural starch a- can come from a wide variety of starch sources, such as, for example, starches from maize, wheat, rice, buckwheat, barley, oats, millet, rye, sorghum, cassava, potato, sweet potato, tapioca, banana, plantain, malanga, taro, chestnut, beans, peas, and preferably native starches from maize, potato, peas, tapioca, rice, cassava, wheat, or mixtures thereof.

[0012] In a particularly preferred embodiment, the natural starch a- is tapioca starch (TAPIOCA STARCH).

[0013] According to one embodiment, the cosmetic composition of the invention comprises from 0.5 to 8%, preferably from 1 to 5%, and more preferably from 1.5 to 4%, by weight of natural starch a- relative to the total weight of said cosmetic composition.

[0014] The elastic mixture of the cosmetic composition of the invention also comprises a β-polyurethane, also called an elastic film-forming polymer, which provides an elastic (comfortable) effect to the composition. The β-polyurethane 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 the effect of multiple mechanical stresses, 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.

[0015] The polyurethane b- of the invention is preferably in the form of an aqueous dispersion of anionic polyurethane, preferably chosen from polyurethane-34, polyurethane-32, polyurethane-35, polyurethane-48, polyurethane-11, polyurethane-2, and their mixtures, marketed for example by Covestro under the names Baycusan® C1000 / 1, Baycusan® C1001 / 1, Baycusan® C1003 / 1, Baycusan® C1004 / 1, Baycusan® C1008 / 1, Baycusan® C1010, or by Wanhua under the names Carfil® 9221, Carfil® UV35, Carfil® 9235NP and Carfil® STI 1. Said aqueous dispersion of anionic polyurethane preferably has a dry extract ranging from 40 to 45% by weight.

[0016] In a particularly preferred embodiment, the polyurethane b- is polyurethane-35 (INCI name: POLYURETHANE-35), for example marketed under the name Baycusan® C1004 / 1 by the company Covestro. It is an aqueous dispersion of anionic polyurethane having a dry extract of 41% by weight.

[0017] The polyurethane b- used in the context of the invention has the advantage of providing, when mixed with the other components of the invention, elastic dry films that are transparent and remain transparent after stretching when they are prepared in the form of 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 alter the color of the deposit on the skin over time.

[0018] Polyurethane b- preferably represents 0.1 to 10%, more preferably 3 to 8%, and even more preferably 5 to 8%, by weight relative to the total weight of the cosmetic composition. When it is in the form of an aqueous dispersion of anionic polyurethane, advantageously having a dry extract of 40 to 45%, said aqueous dispersion of anionic polyurethane preferably represents 1 to 30%, preferably 2 to 25%, and more preferably 5 to 20%, by weight relative to the total weight of the cosmetic composition.

[0019] The average number molecular weight of polyurethane varies advantageously from 100,000 g.mol1 to 500,000 g.mol', more advantageously from 120,000 g.mol1 to 400,000 g.mol*, and even more advantageously from 150,000 g.mol1 to 400,000 g.mol'.

[0020] 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 free volume to the polymer chains, making them more elastic and flexible.

[0021] The c- polyol of the invention is selected from diols, polyglycerols of the formula H-(O-CH2-CH(OH)-CH2)n-OH in which n varies from 2 to 10, and mixtures thereof. The c- polyol may be an alcohol having from 1 to 30 carbon atoms and 2 to 12 hydroxyl groups, and in particular an alcohol having from 2 to 10 carbon atoms and 2 to 4 hydroxyl groups.

[0022] According to one embodiment, the c- polyol is a diol selected from aliphatic or aromatic, linear or branched C 2-Ci2 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.

[0023] 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 2 to 10.

[0024] According to a particularly advantageous embodiment, the c- polyol 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 SAKAMOTO YAKUHIN KOGYO company under reference PGL-S MB. Compared to other polyols, POLYGLYCERIN-3 allows a better level of plasticization of natural starch a- and polyurethane b- on the skin surface.

[0025] The c- polyol preferably represents 0.5 to 8%, preferably 1 to 6%, and more preferably 1.5 to 5%, by weight relative to the total weight of the cosmetic composition.

[0026] In one embodiment, the cosmetic composition of the invention comprises: a- from 0.5 to 8%, preferably from 1 to 5%, and more preferably from 1.5 to 4%, by weight of natural starch a-, b- from 0.1 to 10%, preferably from 3 to 8%, and more preferably from 5 to 8%, by weight of polyurethane b-, and c- from 0.5 to 8%, preferably from 1 to 6%, and more preferably from 1.5 to 5%, by weight of c- polyol, relative to the total weight of the cosmetic composition.

[0027] The quantities of each of the constituents 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 the constituents a-, b-, and c- are adjusted to satisfy the desired compromise between stickiness and adhesion properties. 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 quantity of polyol to be introduced will be greater in order to maintain a certain degree of plasticity and elasticity.

[0028] The mass ratio of the polyol c- relative to the natural starch a- and the polyurethane b- is preferably between 10 / 90 and 60 / 40, and preferably from 20 / 80 to 50 / 50.

[0029] 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 natural starch selected from tapioca starch (TAPIOCA STARCH), b- at least one polyurethane selected from polyurethane-35 (POLYURETHANE-35), and c- at least one diol selected from propane-1,3-diol and polyglycerol of formula H-(O-CH2-CH(OH)-CH2)n-OH in which n = 3 and / or 6 (POLYGLYCERIN-3 and / or POLYGLYCERIN-6), and more preferably propane-1,3-diol, advantageously in the preferred percentages by weight indicated previously.

[0030] In the mixture suitable for forming an elastic film of the cosmetic composition of The invention, natural starch a-, modified polyurethane b-, and polyol c-, are preferably present in proportions such that the elasticity of the dry (water-free) film, with a thickness between 50 and 1000 microns, obtained from said mixture is characterized by:

[0031] - a loss of elasticity, measured after at least one tensile test, of less than 20%, and

[0032] - a resilience of at least 50%.

[0033] 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 texture analyzer (Stable Micro Systems), by measuring the force exerted by a dry film obtained from the mixture and subjected to a tensile test at a controlled speed. The thickness of the film chosen for this measurement is preferably between 50 and 1000 microns, and more preferably between 200 and 400 microns.

[0034] The tensile test consists of 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 controlled rate over a given distance. The forces are recorded by the force sensor located on the fixed part of the machine, and a graph is plotted showing the force exerted by the sample as a function of the sample's elongation, as well as a graph showing the force exerted by the sample as a function of time.

[0035] The residual strain rate is preferably measured after at least one tensile step, at a specified distance equal to one-third of the sample length, for example, at a distance ranging from one-third to four times its length. Alternatively, successive stretching cycles can be performed by gradually increasing the stretching distance.

[0036] The amount of elastic mixture introduced into the cosmetic composition of the invention is advantageously chosen according to the desired cosmetic effect and viscosity. Indeed, the viscosity of the product must be compatible with regular, pleasant, and sufficient application to the skin. The amount 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.

[0037] The proportions of the different components will be optimized to achieve the correct viscoelasticity and adherence to the skin. Depending on the formula, for example, whether it is a foundation or a serum, a compromise will be sought between adherence to the skin and the viscoelasticity of the cosmetic composition. For example, if the formula contains powders, the amount of polyol to be introduced will be greater in order to maintain the plasticity and elasticity of the cosmetic composition.

[0038] 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 suitable for forming an elastic film consisting of natural starch a-, polyurethane b-, and polyol c-, as defined above.

[0039] The cosmetic composition of the invention may further comprise an aqueous phase, which may include water. Preferably, the composition comprises from 40 to 99%, preferably from 50 to 90%, and more preferably from 70 to 80%, by weight of water, relative to the total weight of the cosmetic composition.

[0040] 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 scavenging agent, an agent that repairs the destructive 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, 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.

[0041] The cosmetic composition of the invention may further include a gelling agent. Suitable gelling agents include 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 sold by Ashland) and hydroxypropylcellulose, corn starch, cellulose carboxymethyl ethers (such as Blanose™ 7H3SF sold by Ashland), and bis-decyltetradeceth-20 ether-based copolymers (such as Adeka Nol GT-700 sold by Adeka), polysaccharide alcaligens (such as Alcasealan sold by Iwase Cosfa), and their mixtures.Synthetic polymers can also be advantageously mentioned, preferably chosen from ammonium acryloyldimethyltaurate / VP copolymer (Aristoflex® AVC from Clariant International Ltd.) or acrylates / C 10-30 alkyl acrylate crosspolymer (Carbopol® Ultrez 21). 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), alkaligene polysaccharides (such as Alcasealan sold by Iwase Cosfa), acrylates / C10-30 alkyl acrylate crosspolymer (Carbopol® Ultrez 21), and ammonium acryloyldimethyltaurate / VP. copolymer (Aristoflex® AVC from Clariant International Ltd.), and their mixtures.

[0042] 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 nanopigments, such as zinc, iron and titanium oxides.

[0043] 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.

[0044] Another object of the invention relates to a method for preparing a cosmetic composition according to the invention, as described above.

[0045] 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 natural starch a-, at least one polyurethane b-, and at least one polyol c-, in water, and (ii) dispersion of the mixture obtained in step (i) in an aqueous phase possibly including cosmetic active ingredients and / or excipients.

[0046] In step (i), the elastic mixture can be prepared by first dissolving the polyol c- in water. The natural starch a- is then dissolved or dispersed in the water-polyol c- mixture, possibly with the addition of heat and stirring. Advantageously, the natural starch a- is dispersed in the water-polyol c- mixture, under 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. Once the natural starch a- has dissolved or dispersed, the polyurethane b- is then added. Advantageously, the mixture is cooled to a temperature below 40°C before the polyurethane b- is added.

[0047] In step (ii), the mixture prepared in step (i) is added to an aqueous phase comprising cosmetic actives and / or other cosmetic excipients.

[0048] According to another embodiment, the cosmetic composition of the invention is prepared by successively adding each of the components natural starch a-, polyurethane b-, and polyol c-, directly into the aqueous phase of the cosmetic composition, without prior mixing.

[0049] In the particular case of an emulsion, the components natural starch a-, polyurethane b-, and polyol c-, are added to the aqueous dispersing phase before dispersion of the oily phase.

[0050] 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.

[0051] 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.

[0052] The cosmetic composition, when applied directly to the skin, forms a film after application and gradual evaporation of the water in the composition. This film exhibits elastic mechanical properties and a texture particularly well-suited to makeup application. 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 the skin of the face.

[0053] 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.

[0054] In addition to the foregoing provisions, the invention also includes other provisions which will become apparent from the following supplementary description, which relates to the preparation of cosmetic compositions according to the invention.

[0055] Examples:

[0056] In the examples, 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.

[0057] Methods for characterizing elastic films: - Elastic properties (resistance to fatigue): Fatigue resistance was evaluated using a TA.XT Plus texture analyzer (Stable Micro Systems). Prepared elastic films were poured into Teflon® molds and then dried at 33°C under 50% relative humidity to a thickness of 200 to 400 µm sec. 5 x 3 cm specimens were then cut and subjected to repeated stretching: 25 stretch cycles at 50% back and forth at 1 mm / second. Elastic properties (fatigue resistance) were classified from most elastic (+++) to least elastic (+). - Evaluation of the contractile effect on nitrile support: The contractile effect of elastic films was visually assessed at room temperature (20°C). A nitrile glove cut into a 3 x 5 cm test tube was used as a support. The elastic mixtures were spread with a spatula onto the nitrile support to obtain a dry film mass of 0.05 g, corresponding to a dry film thickness (or remaining dry mass) of 33 µm, and then left to dry for 24 hours at room temperature (20°C). During the drying process, the elastic films contracted to varying degrees and were classified into three categories:

[0058] Category 1: the support is not retracted, the film exhibits no contractile effect,

[0059] Category 2: the support has slightly retracted compared to the start of the test, an effect contractile muscle is visible.

[0060] 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 is to evaluate and compare the smoothing effect on the area at the corner of the eye known as "crow's feet" after 1 hour and 4 hours on a panel of 10 volunteers. All measurements were taken at a temperature of 22°C and 50% relative humidity.

[0061] 1 - Taking an impression

[0062] A first impression was taken before application of the evaluated cosmetic composition. To create the impression, a film-forming resin was spread using a spatula over the area being studied. After drying, the replica of the skin area was peeled off.

[0063] The product was applied to the crow's foot in an amount of 2 mg.cm2, left to dry for 15 minutes, then measurements were taken after 1 hour and 4 hours.

[0064] A second impression was taken 1 hour and then 4 hours after application of the cosmetic composition. The same protocol was repeated for each cosmetic composition studied.

[0065] 2- Image analysis

[0066] Each replica was positioned on a support and illuminated with a grazing light at an angle of incidence of 35° 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.

[0067] Device used:

[0068] The QU ANTIRIDES® software calculates the following parameters: number of wrinkles, total surface area of ​​wrinkles in mm2, total length of wrinkles in mm, average length of wrinkles in mm, average depth of wrinkles in pm.

[0069] 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 the areas of wrinkles, their length and / or their surface area or depth, the more significant the observed smoothing effect.

[0070] Evaluation criteria:

[0071] +++ means that the product has a very significant smoothing effect on crow's feet, 1 or 4 hours after application,

[0072] ++ means that the product has a significant smoothing effect on crow's feet, 1 or 4 hours after application, and

[0073] + means that the product has little smoothing effect on crow's feet, 1 or 4 hours after application.

[0074] Example 1: Preparation and characterization of elastic mixtures

[0075] 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:

[0076] [Tables 1] Natural starch a-(% by weight) Polyurethane b-(% by weight) Polyol c-(% by weight) Elastic blend A TAPIOCA STARCH: 2% POLYURETHANE-35 (41% dry extract): 15% (6% active ingredient) PROPANE-1,3-DIOL: 2.5% Elastic blend B TAPIOCA STARCH: 2% POLYURETHANE-35 (41% dry extract): 15% (6% active ingredient) POLYGLYCERIN-3: 2.5% Elastic blend C TAPIOCA STARCH: 2% POLYURETHANE-35 (41% dry extract): 15% (6% active ingredient) VEGETABLE GLYCEROL: 2.5%

[0077] Three aqueous dispersions, each comprising one of the mixtures A, B and C, were prepared according to the formula in Table 2 below:

[0078] [Tables2] Ingredients (chemical names or INCI) Phases Quantities (% by weight) PURIFIED WATER Al 80.2 CHLORPHENESIN Al 0.3 POLYOL C- Al 2.5 TAPIOCA STARCH A2 2 POLYURETHANE-35 (at 41% dry extract) A3 15

[0079] The ingredients of phase A1 were weighed into a beaker and then mixed using a deflocculating turbine at 85°C. Phase A2 was weighed into a capsule and then added to phase A1 as a fine spray. The mixture was then blended at 400 rpm for 30 minutes at 85°C. The heating was stopped to allow the temperature to return to room temperature. Phase A3 was weighed into a small dish, then added to the beaker, and finally blended for 15 minutes. The prepared mixtures were then used to form elastic films, which were evaluated.

[0080] The measured characteristics for elastic mixtures A, B and C are summarized in the following Table 3:

[0081] [Tables3] Elastic properties Category of contractile effect Elastic mixture A++ 3 Elastic mixture B+++ 2 Elastic mixture C+++ 1

[0082] Elastic mixtures A and B are those which allow the best compromise between tensing effect and elastic effect, with a better feeling for elastic mixture B based on POLYGLYCERIN-3.

[0083] Example 2: Preparation and characterization of serum-type cosmetic compositions

[0084] Two serum formulas 1 and 2 according to the invention and five formulas 3, 4, 5, 6 and 7 outside The following inventions, corresponding to the following compositions, have been prepared:

[0085] [Tables4] Ingredients (chemical names or INCI) Phases Quantities (% by weight) Formula 1 Formula 2 Formula 3 Formula 4 Formula 5 Formula 6 PURIFIED WATER Al 70.58 70.58 70.58 85.58 74.63 74.63 CHLORPHENESIN Al 0.27 0.27 0.27 0.27 0.27 0.27 TAPIOCA NATURAL A2 4.00 4.00 4.00 4.00 - - CROSSLINKED HYALURONIC ACID A3 0.20 0.20 0.20 0.20 0.20 0.20 HYALURONIC ACID POWDER A3 0.30 0.30 0.30 0.30 0.30 0.30 A4 0.30 0.30 0.30 0.30 0.30 0.30 SODIUM SURFACTIN A4 0.10 0.10 0.10 0.10 0.10 0.10 PURIFIED WATER A5 0.95 0.95 0.95 0.95 0.90 0.90 SODIUM HYDROXIDE A5 0.05 0.05 0.05 0.05 0.05 0.05 PURIFIED WATER A6 0.90 0.90 0.90 0.90 0.90 0.90 TRISODIUM CITRATE DIHYDRATE A7 0.09 0.09 0.09 0.09 0.09 0.09 CITRIC ACID A7 0.01 0.01 0.01 0.01 0.01 0.01 PIGMENT A8 0.40 0.40 0.40 0.40 0.40 0.40 GLYCERIN A9 - - 5.00 5.00 5.00 - POLYGLYCERIN-3 A9 5,00 - - - - 5,00 PROPANEDIOL A9 5,00 - - - - JOJOBA EMOLLIENT A9 1,00 1,00 1,00 1,00 1,00 1,00 POLYURETHANE-3 5 A10 15,00 15,00 15,00 - 15,00 15,00 CAPRYLYL GLYCOL Ail 0,50 0,50 0,50 0,50 0,50 0,50 ,

[0086] The ingredients of phase A1 were weighed into a beaker and then mixed using a deflocculating turbine at 80°C. Phase A2 was weighed, added to phase A1 as a fine spray, and mixed at 300 rpm for 30 minutes. Phase A3 was weighed, added to phase A1 as a fine spray, and mixed at 300 rpm for 30 minutes. Phase A4 was weighed, added to phase A1 as a fine spray, and mixed at 600 rpm for 30 minutes. Phase A5 was weighed and added to phase A1. Phase A6 was weighed and added to phase A1. Phase A7 was weighed and added to phase A1. The heating was stopped to allow the temperature to return to ambient temperature. Phase A8 was weighed and added to phase AL. Phase A9 was weighed and added to phase AL. Phases A10 and A11 were weighed and added successively to phase AL.

[0087] The measured characteristics for formulas 1 to 7 are summarized in the following Table 5:

[0088] [Tables5] In vivo smoothing effect (4 hours) Formula 1 ++ +++ Formula 2 +++ ++ Formula 3 No smoothing effect No smoothing effect Formula 4 ++ No smoothing effect Formula 5 + + Formula 6 No smoothing effect +

Claims

Demands

1. Cosmetic composition characterized in that it comprises a mixture capable of forming a film comprising: a- at least one natural starch, b- at least one polyurethane, 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 2 to 10, and mixtures thereof, said polyol c- being selected from 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 / or said polyol c- being a polyglycerol of formula H-(O-CH2-CH(OH)-CH2)n-OH in which n varies from 2 to 10.

2. Composition according to claim 1, characterized in that the natural starch a- is selected from native starches of maize, potato, pea, tapioca, rice, cassava, wheat, or mixtures thereof.

3. Composition according to claim 2, characterized in that the natural starch a- is tapioca starch (TAPIOCA STARCH).

4. Composition according to any one of claims 1 to 3, characterized in that the polyurethane b- is in the form of an aqueous dispersion of anionic polyurethane, preferably selected from polyurethane-34, polyurethane-32, polyurethane-35, polyurethane-48, polyurethane-11, polyurethane-2, and mixtures thereof, and more preferably polyurethane-35 (POLYURETHANE-35).

5. Composition according to any one of claims 1 to 4, characterized in that the c- polyol is propane-1,3-diol.

6. Composition according to any one of claims 1 to 4, characterized in that the c- polyol is a polyglycerol of formula H-(O-CH2-CH(OH)-CH2)n-OH in which n varies from 2 to 4, the c- polyol 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).

7. A composition according to any one of claims 1 to 6, characterized in that it comprises a mixture capable of forming a film comprising: a- at least one natural starch selected from tapioca starch (TAPIOCA STARCH), b- at least one polyurethane selected from polyurethane-35 (POLYURETHANE-35), and c- at least one diol selected from propane-1,3-diol and polyglycerol of formula H-(O-CH2-CH(OH)-CH2)n-OH in which n = 3 and / or 6 (POLYGLYCERIN-3 and / or POLYGLYCERIN-6), and preferably propane-1,3-diol.

8. Composition according to any one of claims 1 to 7, characterized in that it comprises from 0.5 to 8%, preferably from 1 to 5%, and more preferably from 1.5 to 4%, by weight of natural starch a- relative to the total weight of the cosmetic composition.

9. Composition according to any one of claims 1 to 8, characterized in that it comprises from 0.1 to 10%, preferably from 3 to 8%, and more preferably from 5 to 8% by weight of polyurethane b- relative to the total weight of the cosmetic composition.

10. Composition according to any one of claims 1 to 9, characterized in that it comprises from 0.5 to 8%, preferably from 1 to 6%, and more preferably from 1.5 to 5%, by weight of c- polyol relative to the total weight of the cosmetic composition.

11. Composition according to any one of claims 1 to 10, characterized in that the weight ratio polyol c- / (natural starch a- + polyurethane b-) varies from 10 / 90 to 60 / 40, and preferably from 20 / 80 to 50 / 50.

12. Composition according to any one of claims 1 to 11 characterized in that the mixture of natural starch a-, polyurethane 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.

13. Composition according to any one of claims 1 to 12 characterized in that it comprises water, preferably in an amount 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.

14. Composition according to any one of claims 1 to 13 characterized in that it is in the form of a gel, a lotion, a serum, a suspension, an oil-in-water emulsion or a water-in-oil emulsion.

15. A process for preparing a cosmetic composition according to any one of claims 1 to 14, characterized in that it comprises the following steps: (i) preparing a film-forming mixture by dissolving at least one natural starch (a), at least one polyurethane (b), and (i) less a c- polyol, in water, and (ii) dispersion of the mixture obtained in step (i) in an aqueous phase comprising cosmetic actives and / or excipients.

16. Skin care method characterized in that it comprises a step of applying a composition as defined according to any one of claims 1 to 14, on at least one part of the body and / or face.

17. A method according to claim 16, 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 loss of firmness, loss of elasticity, or sagging skin, to obtain an effect selected from a smoothing effect, a tightening effect, a skin-bouncing effect, or a combination of one of these effects.