Compositions comprising chitosan and mineral pigments subjected to nano-specific surface treatment

Abstract

The present invention relates to a cosmetic composition comprising, in a physiologically acceptable aqueous medium: a) at least 0.01% by weight, relative to the total weight of the composition, of natural chitosan having a molecular weight strictly greater than 3000 Daltons in an amount strictly less than 15% by weight, and b) at least one surface-treated mineral pigment having a size less than or equal to 100 nm. The invention also relates to a method for making up and / or caring for the skin and / or skin appendages, wherein a composition according to the invention is applied to the skin and / or skin appendages.

Description

TECHNICAL FIELD

[0001] The present invention relates to a cosmetic composition comprising, in a physiologically acceptable aqueous medium: a) at least 0.01 % by weight, relative to the total weight of the composition, of natural chitosan having a molecular weight strictly greater than 3000 Daltons, this amount being strictly less than 15% by weight, and b) at least one surface-treated mineral pigment, said pigment having a size less than or equal to 100 nm.

[0002] The present invention also relates to a method for making up and / or caring for the skin and / or the skin appendages, in which a composition according to the invention is applied to the skin and / or the skin appendages. BACKGROUND

[0003] For many cosmetic compositions, it is desirable that the deposit film after application to keratin materials be resistant. For example, lipsticks or nail varnishes are among them. To obtain this effect, specific raw materials, in particular film-forming agents, can be used in combination. However, the presence of such agents for the resistance of the film on keratin materials results in a composition that causes drying. Furthermore, the film-forming agents generally used are generally petroleum chemical products in nature, such as silicones or acrylic polymers.

[0004] Furthermore, it is generally sought to obtain compositions with good coverage power.

[0005] Thus, formulators are looking for raw materials and / or systems that make it possible to obtain fluid (i.e. flowing) compositions whose deposit is covering, uniform and resistant (i.e. with good resistance), in particular with good water resistance.

[0006] Furthermore, formulations of environmentally friendly solutions, designed and developed taking into account environmental challenges, are becoming a major concern to help tackle global challenges.

[0007] Thus, it becomes essential to propose more sustainable compositions and / or preparation processes and / or ingredients to tackle these environmental challenges.

[0008] In this context, it is important to develop new cosmetic compositions with a better carbon footprint, in particular by promoting the use of renewable raw materials and / or those with a good wilderness quality index and / or of natural origin, and more particularly of plant origin, while reducing the use of compounds of petrochemical origin. SUMMARY

[0009] The aim of the present invention is to provide aqueous cosmetic compositions that have good cosmetic properties, in particular in terms of coverage power and uniformity, but also good resistance, in particular with good water resistance.

[0010] After application, these compositions leave a covering and uniform film-forming deposit, which has good resistance to abrasion. The film formed is adherent and cohesive and has enhanced water resistance.

[0011] Furthermore, the surface treatment of mineral pigments, said pigments having a size less than or equal to 100 nm, makes it possible to increase the sun protection factor of the composition obtained.

[0012] These compositions also comprise sustainable ingredients, thus enabling them to meet environmental challenges.

[0013] The present application thus relates to a cosmetic composition, in particular for making up and / or caring for the skin and / or the lips, in particular for skin care, comprising, in a physiologically acceptable aqueous medium: a) at least 0.01 % by weight, relative to the total weight of the composition, of natural chitosan having a molecular weight strictly greater than 3000 daltons, this amount being strictly less than 15% by weight, and b) at least one surface-treated mineral pigment, said pigment having a size less than or equal to 100 nm.

[0014] “Physiologically acceptable” means a medium that is compatible with keratin materials.

[0015] The present application also relates to a process for making up and / or caring for the skin and / or the skin appendages, in which the composition according to the application is applied to the skin and / or the skin appendages.

[0016] Preferably, the composition according to the application is substantially free of (meth)acrylic polymers. Preferably, the composition according to the application is substantially free of silicone.

[0017] “Substantially free of (meth)acrylic polymers” means that the composition comprises less than 1 % by weight, preferably less than 0.5% by weight, preferably less than 0.3% by weight, preferably less than 0.1 % by weight, of (meth)acrylic polymers, relative to the total weight of the composition. Preferably, the composition is completely free of (meth)acrylic polymers. By (meth)acrylic polymers, we mean polymers comprising at least one acrylic monomer or at least one methacrylic monomer.

[0018] “Substantially free of silicone” means that the composition comprises less than 1 % by weight, preferably less than 0.5% by weight, preferably less than 0.3% by weight, preferably less than 0.1 % by weight, of silicone, relative to the total weight of the composition. Preferably, the composition is completely free of silicone. By silicone, we mean any silicone compound.

[0019] Chitosan The composition according to the application comprises at least 0.01 % by weight of at least one natural chitosan having a molecular weight strictly greater than 3000 Daltons (3 kDa) (1 Da = 1 g / mol) relative to the total weight of the composition.

[0020] The amount of natural chitosan is strictly less than 15% by weight relative to the total weight of the composition.

[0021] Preferably, the natural chitosan has a molecular weight greater than or equal to 10 kDa, preferably greater than or equal to 15 kDa, preferably greater than or equal to 20 kDa. Preferably, the natural chitosan has a molecular weight between 10 kDa and 2 MDa, preferably between 15 kDa and 1.5 MDa, preferably between 20 kDa and 300 kDa, preferably between 20 kDa and 200 kDa.

[0022] Chitosan is obtained by deacetylation of chitin. Chitin is a polysaccharide composed of several N-acetyl-D-glucosamine units linked to each other by beta-(1,4) type bonds.

[0023] The ideal chemical structure of chitosan is a chain of beta-D-glucosamine monomers linked by glycosidic (1→4) bonds.

[0024] According to the application, "chitosan" means any copolymer composed of units of N-acetyl-D-glucosamine and D-glucosamine, the degree of acetylation of which is less than 90%. Chitosan is composed of glucosamine sugar units (deacetylated units) and N-acetyl-D-glucosamine units (acetylated units) linked to each other by beta (1,4) type bonds and represents a polymer of the poly(N-acetyl-D-glucosamine)-poly(D-glucosamine) type.

[0025] Preferably, the degree of acetylation of chitosan is less than or equal to 80%, preferably less than or equal to 70%, preferably less than or equal to 60%, preferably less than or equal to 50%, preferably less than or equal to 35%, preferably less than or equal to 25%, and preferably less than or equal to 15%.

[0026] The degree of acetylation is the percentage of acetylated units relative to the total number of units and can be determined by Fourier transform infrared spectroscopy (FTIR) or titration with a strong base.

[0027] The chitosan of the application is preferably a polysaccharide prepared from a fungal source. The chitosan of the application is in particular extracted and purified from a safe and abundant food-grade or biotechnological fungal source such as Agaricus bisporus ( Agaricus bisporus ) or Aspergillus niger ( Aspergillus niger ).

[0028] The chitosan of the application is preferably derived from mycelium of an Ascomycete fungus, in particular Aspergillus niger, and / or a Basidiomycete fungus, in particular Lentinula edodes (shiitake) and / or Agaricus bisporus. Lentinula edodes (shiitake) and / or Agaricus bisporus. Agaricus bisporus ) Preferably, the fungus is Aspergillus niger. Aspergillus niger

[0029] The chitosan can be GMO-derived, but is preferably non-GMO-derived.

[0030] The chitosan according to the application is natural, i.e. it has not been modified. In particular, it has not been subjected to any chemical modification.

[0031] A method for preparing chitosan is described in application WO03068824.

[0032] Preferably, the chitosan used in the present application is in powder form. It is notably sold by Kitozyme under the name Kiosmetine or Kionutrime.

[0033] The chitosan is preferably present in an amount of 0.01 to 14% by weight, preferably 0.1 to 14% by weight, preferably 0.1 to 12% by weight, preferably 0.2 to 7% by weight, preferably 0.25 to 5% by weight, relative to the total weight of the composition.

[0034] Nanosurface-treated mineral pigments The composition according to the application comprises at least one surface-treated mineral pigment, said pigment having a size of less than or equal to 100 nm (“nano-surface-treated mineral pigment”).

[0035] The term “pigment” means a white or coloured mineral particle which is insoluble in aqueous solution and which is intended to colour the composition and / or the resulting deposit.

[0036] The treated pigment can be present in the composition in a content of 1 to 70% by weight, preferably 1 to 60% by weight, preferably 1 to 50% by weight, preferably 3 to 45% by weight, preferably 4 to 30% by weight, preferably 6 to 20% by weight, preferably 6 to 15% by weight, relative to the weight of the composition.

[0037] Preferably, the weight ratio between the nano-surface-treated mineral pigment and the chitosan (i.e. the weight ratio pigment: chitosan) is greater than 1, preferably between 1 and 30. Preferably, the weight ratio is between 1 and 25, preferably between 5 and 20.

[0038] Mineral pigments ​By "mineral pigments" is meant any pigments meeting the definition in the chapter on inorganic pigments in Ullmann's Encyclopedia.

[0039] The size of the mineral pigments that can be used within the scope of the application is nanometric, i.e. less than or equal to 100 nm. According to a particular embodiment of the application, the size of the pigments is characterized in that the D

[50] is less than 100 nm, preferably less than 50 nm, preferably between 5 nm and 40 nm, preferably between 10 nm and 30 nm.

[0040] This size is measured by means of a commercial MasterSizer 3000 from Malvern ® The particle size analyser measures by measurement of static light scattering, making it possible to understand the particle size distribution of all the particles over a wide range of 0.01 pm to 1000 pm. The data are processed on the basis of the classic Mie scattering theory. This theory is best suited to size distributions ranging from submicron to several microns and makes it possible to determine the "effective" diameter of the particles. This theory is described in detail in the book by Van de Hulst, H.C., "Light Scattering by Small Particles", chapters 9 and 10, Wiley, New York, 1957.

[0041] D

[50] represents the maximum size of 50% by volume of the particles.

[0042] Any mineral pigments having a nanometric size can be used in the application.

[0043] Among the mineral pigments that can be used in the application, mention can be made of titanium dioxide, iron oxides (black, yellow or red), zirconium or cerium oxides, zinc or chromium oxides, manganese violet, ultramarine blue, chromium hydrate and iron blue, metallic powders such as aluminium and copper powder.

[0044] Preferably, the mineral pigments are more particularly titanium dioxide.

[0045] Mention can also be made of nacres and / or pigments which, once they have a nanometric size, have an optical effect that is different from a simple conventional toning effect (for example a monochromatic pigment).

[0046] The term "nacre" is understood to mean coloured particles, of any shape, which are iridescent or non-iridescent, which are in particular produced by certain molluscs in their shells, or are synthetic, and which exhibit a colour effect by optical interference.

[0047] The nacres can be chosen from pearl pigments such as titanium mica coated with an iron oxide, titanium mica coated with a bismuth oxychloride, titanium mica coated with a chromium oxide, titanium mica coated with an organic dye, and a pearl pigment based on bismuth oxychloride. This can also involve mica particles on which at least two successive layers of metal oxides and / or organic dyes are superimposed on the surface. By way of example of nacres, mention can also be made of natural micas coated with titanium oxide, iron oxide, natural pigments or bismuth oxychloride. The nacres can more particularly have a yellow, pink, red, bronze, orange, brown and / or coppery or lustrous color.

[0048] Among the pigments that can be used according to the application, mention can also be made of those having an optical effect that is different from a simple conventional toning effect, i.e. a uniform and stable effect as produced by conventional dyes, for example monochromatic pigments.

[0049] For the purposes of the present application, "stable" means the absence of an effect of variability of the color with the angle of observation or in response to a change in temperature.

[0050] Surface treatment agent The surface treatment agent according to the application is a hydrophobizing agent. The hydrophobizing agent is preferably chosen from fatty acids, metal salts and mixtures thereof.

[0051] Fatty acid "Fatty acid" means a carboxylic acid having an aliphatic chain comprising from 8 to 30 carbon atoms, preferably from 12 to 24 carbon atoms, more preferentially from 16 to 18 carbon atoms. The fatty acid can be liquid or non-liquid.

[0052] Liquid fatty acid means a fatty acid that is liquid at ordinary temperature (25°C) and at atmospheric pressure (760 mmHg, i.e. 1,013.10 5 Pa).

[0053] The fatty acid of the application can be saturated or unsaturated.

[0054] The fatty acid suitable for implementing the application is more particularly chosen from linear or branched, saturated or unsaturated acids containing from 8 to 30 carbon atoms.

[0055] Preferably, the fatty acid is chosen from stearic acid, palmitic acid, palmitoleic acid, linoleic acid, octanoic acid, myristic acid, lauric acid, behenic acid and isostearic acid.

[0056] Metal salt The metal salt is preferably a hydroxide, for example aluminum hydroxide; a hydroxide of an alkali metal such as sodium or potassium; or a hydroxide of an alkaline earth metal such as magnesium.

[0057] Preferably, the metal salt is aluminum hydroxide.

[0058] Preferably, the surface treatment agent according to the application is a mixture of a fatty acid and a metal salt, preferably a mixture of stearic acid and aluminum hydroxide.

[0059] Preferably, the nanosurface-treated mineral pigment according to the application is a nanotitanium dioxide treated with aluminum hydroxide and stearic acid, such as the nanotitanium dioxide sold under the name MICRO TITANIUM DIOXIDE MT-100 T V by TAYCA.

[0060] Physiologically acceptable aqueous medium The composition according to the application comprises a physiologically acceptable aqueous medium. The medium comprises water.

[0061] The water used can be sterile demineralized water and / or floral water, such as rose water, cornflower water, chamomile water or linden tree water, and / or spring water or natural mineral water.

[0062] The composition preferably comprises at least 5% by weight, preferably at least 10% by weight, preferably at least 20% by weight, preferably at least 30% by weight, preferably at least 40% by weight of water, relative to the total weight of the composition.

[0063] The composition preferably comprises from 5% to 95% by weight, more preferentially from 10% to 85% by weight, even more preferentially from 20% to 80% by weight, even more preferentially from 25% to 70% by weight, even more preferentially from 28% to 60% by weight, even more preferentially from 30% to 50% by weight of water, relative to the total weight of the composition.

[0064] The aqueous phase can also comprise, at 25°C, at least one organic solvent miscible with water.

[0065] Preferably, the organic solvent miscible with water is chosen from alcohols, polyols and mixtures thereof.

[0066] Among the alcohols, mention can be made of Ci-Ci2alcohols, preferably Ci-C5alcohols, such as ethanol, isopropanol, propanol and butanol. 10 , more preferentially Ci-C5alcohols, such as ethanol, isopropanol, propanol and butanol.

[0067] The polyols, preferably, are chosen from polyols having from 2 to 20 carbon atoms, preferably from 2 to 6 carbon atoms, such as glycerol, diglycerol, propylene glycol, isoprene glycol, dipropylene glycol, butylene glycol, hexylene glycol, 1,2-propanediol, 1,3-propanediol, pentylene glycol, polyethylene glycol having from 2 to 200 ethylene oxide units and mixtures thereof.

[0068] The composition can comprise from 0.1% to 25% by weight, more preferentially from 0.5% to 20% by weight, even more preferentially from 0.9% to 15% by weight of the organic solvent miscible with water, relative to the total weight of the composition.

[0069] Alpha hydroxy acid (AHA) The composition according to the application can comprise at least one AHA.

[0070] According to the application, by alpha hydroxy acid is meant a carboxylic acid having at least one hydroxyl function occupying an alpha position on said acid (carbon adjacent to the carboxylic function). This acid can be present in the final composition in the form of the free acid and / or in the form of one of its associated salts, in particular with an organic base or an alkali metal, in particular according to the final pH imposed on the composition.

[0071] The alpha-hydroxy acid (alpha hydroxy acid or AHA) is for example chosen from lactic acid, citric acid, methyl lactic acid, glucuronic acid, glycolic acid, pyruvic acid, 2-hydroxybutyric acid, 2-hydroxyvaleric acid, 2-hydroxyhexanoic acid, 2-hydroxyheptanoic acid, 2-hydroxyoctanoic acid, 2-hydroxynonanoic acid, 2-hydroxydecanoic acid, 2-hydroxyundecanoic acid, 2-hydroxydodecanoic acid, 2-hydroxytetradecanoic acid, 2-hydroxyhexadecanoic acid, 2-hydroxyoctadecanoic acid, 2-hydroxytetracosanoic acid, 2-hydroxyeicosanoic acid, mandelic acid, phenyllactic acid, gluconic acid, galacturonic acid, alepunic acid, ribonic acid, tartronic acid, tartaric acid, malic acid, fumaric acid, their salts, and mixtures thereof.

[0072] According to a preferred embodiment, the alpha hydroxy acid is chosen from lactic acid, citric acid, malic acid, tartaric acid and their salts. More particularly, the alpha hydroxy acid is chosen from lactic acid, citric acid, their salts and mixtures thereof.

[0073] The alpha hydroxy acid can be present in an amount ranging from 0.001 to 10% by weight, from 0.005 to 5% by weight, preferably from 0.01 to 3% by weight, relative to the total weight of the composition.

[0074] Surfactant The composition can comprise at least one surfactant. The surfactant is preferably chosen from anionic, cationic, nonionic, zwitterionic and amphoteric surfactants. Preferably, the surfactant is chosen from: a) non-ionic surfactants, in particular non-ionic surfactants with an HLB greater than or equal to 8 at 25°C, which can be used alone or in mixture. Mention can be made in particular of esters of fatty acids and of polyglycerol, esters of fatty acids and of polyethylene glycol, alkyl C8-C30 (poly)glycosides or mixtures thereof. In particular, the non-ionic surfactant can be an ester of a fatty acid comprising from 10 to 18 carbon atoms and of a polyglycerol comprising from 2 to 10 glycerol units. In a preferred embodiment of the application, the fatty acid ester comprises 12 carbon atoms and 10 glycerol units and is polyglyceryl monolaurate comprising 10 glycerol units, i.e. polyglyceryl-10 monolaurate (sold under the trade name DERMOFEEL G10L by Dr Straetmans). It can also be polyglyceryl-2 monooleate (sold under the trade name SUNSOFT Q-17D(G)-C by TAIYO KAGAKU), or polyglyceryl-4 monocaprate or PG-4 caprate (sold under the trade name TEGOSOFT PC 41 by EVONIK GOLDSCHMIDT).

[0075] b) anionic surfactants such as: polyoxyethylenated fatty acid salts, in particular those derived from alkaline salts, and mixtures thereof; phosphoric esters and their salts, such as "DEA oleth-10 phosphate" (Crodafos N 10N sold by CRODA) or potassium monohexadecyl phosphate (Amphisol K sold by Givaudan); sulfosuccinates, such as "PEG-5 citrate lauryl sulfosuccinate" and "Ricinoleamido MEA sulfosuccinate" di-sodium; alkyl ether sulfates, such as sodium lauryl ether sulfate; isethionates; acyl glutamates, such as "di-sodium hydrogenated tallow glutamate" (Amisoft HS-21R sold by AJINOMOTO ® ) and sodium stearoyl glutamate (AMISOFT HS-11 PF sold by AJINOMOTO ® ) and mixtures thereof; derivatives of soybean, such as potassium soyate; citrates, such as glyceryl stearate citrate (Axol C 62 pellets sold by Degussa); derivatives of proline, such as sodium palmitoyl proline (Sepicalm VG sold by Seppic), or mixtures of sodium palmitoyl cysteate, magnesium palmitoyl glutamate, palmitic acid and palmitoyl proline (Sepifeel One sold by Seppic); Lactylates such as sodium stearoyl lactylate (Akoline SL, ex Karlshamns AB); Sarcosinates such as sodium palmitoyl sarcosinate (Nikkol sarcosinate PN), or a 75 / 25 mixture of stearoyl sarcosinate and myristoyl sarcosinate (Crodasin SM, ex Croda); Sulfonates such as sodium C14-17 sec alkylsulfonate (Hostapur SAS 60, ex Clariant); Glycinates such as sodium cocoyl glycinate (Amilite GCS-12, ex Ajinomoto); C16-C30 fatty acid salts, in particular those derived from amines such as triethanolamine stearate and / or amino-2-methyl-2-propane diol-1,3 stearate; c) amphoteric surfactants such as N-acyl-amino acids such as N-alkyl-amino acetates, disodium cocoamphoacetate and amine oxides such as stearamine oxide or even silicone surfactants such as dimethicone copolyol phosphate, for example under the trade name PECOSIL PS 100 ® products sold; and mixtures thereof.

[0076] pH of the composition The composition according to the application has a pH less than or equal to 7, preferably less than or equal to 6.5, preferably less than or equal to 6.3. Advantageously, the pH of the composition is between 3 and 6.3, preferably between 4 and 6.3.

[0077] Preferably, the cosmetic composition according to the application comprises at least one base and / or at least one acid. The bases and acids according to the application are known and are conventionally used in the cosmetic field.

[0078] The base and / or the acid are in particular used to adjust the final pH of the composition between 3 and 6.3.

[0079] The acid can be, for example, citric acid.

[0080] The base can be chosen from mineral bases, for example alkali metal hydroxides, such as sodium hydroxide, potassium hydroxide.

[0081] Preferably, the base of the composition is an alkali metal hydroxide, preferably sodium hydroxide or potassium hydroxide.

[0082] The composition according to the application can comprise at least one base, the active material content of which is from 0.5% to 10% by weight, in particular from 1% to 5% by weight, preferably from 1% to 4% by weight, relative to the total weight of the composition.

[0083] The composition according to the application is conventionally obtainable by the person skilled in the art.

[0084] The application also relates to a method for making up and / or caring for the skin and / or the skin appendages, in which a composition according to the application is applied to the skin and / or the skin appendages. DETAILED DESCRIPTION

[0085] The following examples make it possible to better understand the application, without in any way being limiting. The raw materials are denoted by their chemical name or their INCI name. The amounts indicated are % (% w / w) of raw material relative to the total weight of the composition, unless otherwise indicated.

[0086] Example 1 : Preparation of the composition according to the application and comparison with a comparative composition The composition A according to the application, as well as the comparative composition B, are prepared by mixing the ingredients of Table 1.

[0087] The composition A according to the application comprises Ti02surface-treated with aluminium hydroxide and stearic acid.

[0088] The comparative composition B does not contain chitosan.

[0089] The composition A according to the application has a good carbon footprint, in particular by promoting the use of raw materials that are renewable and / or that have a good wilderness quality index and / or that are of natural origin, and more particularly of plant origin.

[0090] The results are in Table 1.

[0091] [Table 1]

[0092] The formulations are prepared according to the same method as follows: The lactic acid and the chitosan are mixed with the rotor-stator from VMI until the chitosan is completely dissolved. The glycerin and the polyglyceryl-10 laurate are added with gentle stirring. The Ti02is then gradually added and kept under stirring for 20 minutes.

[0093] Evaluation: Macroscopic: The samples are observed 24 hours after preparation in order to detect any phase separation of the system.

[0094] Tolerance: To assess the resistance to dry, water and oil rubs, 30 μΙ of the preparation was deposited on a 5 x 5 cm2black plate. Each spread was performed with the fingers by making 5 back and forth passes, then a light circling on the whole surface. The deposits were left to dry in the open air for 3 hours. They were then subjected to various rubbing stresses: - Dry rub: each deposit was rubbed back and forth with the fingers 15 times; - Water rub: each deposit was rubbed back and forth with the fingers 15 times after water deposition; - Water rub + dry cloth rub: each deposit was rubbed with the fingers 15 times then wiped with a dry cloth; - Oil (octyldodecanol) rub + dry cloth rub: each deposit was rubbed with the fingers 15 times then wiped with a dry cloth.

[0095] Results: Macroscopic: The samples showed no phase separation. However, chitosan allowed a better stabilization of the Ti02dispersion.

[0096] Tolerance: The resistance evaluation of all the deposits subjected to various stresses showed a clear difference between the samples with and without chitosan. The deposits with chitosan remained intact after the stresses, while the deposits without chitosan degraded substantially.

[0097] All the results are summarized in the following table: [Table 2]

[0098] The comparative formulation without chitosan B showed, in addition to a fast phase separation, a deliquoring of the Ti02on the surface forming a cloud of potentially inhalable powder.

[0099] Example 2: Evaluation of the SPF of the composition according to the application and comparison with a comparative composition This protocol consists in comparing the in vitro sun protection factor (SPF) of the aqueous formulation according to the application with a comparative oily formulation with the same amount of the same Ti02.

[0100] The two formulations tested were prepared as described in example 1.

[0101] [Table 3]

[0102] In vitro SPF evaluation Filtering efficiency evaluation protocol In vitro: The Sun Protection Factor (SPF) was determined based on the initial absorbance according to the "in vitro" method described by M. Pissavini et al in International Journal of Cosmetic Science, 40, 263-268 (2018).

[0103] The in vitro UVA Protection Factor UVA (UVAPF) of the sunscreen product against UVA radiation was mathematically calculated by in vitro spectroscopic modeling according to the ISO 24443:2012 (Fr) protocol.

[0104] Each composition was applied in the form of a uniform and regular deposit at a rate of 1 mg / cm2on six rough PMMA plates. An automatic robot was used to perform a regular and uniform movement to spread each composition on three plates called HD6 (molded particle plates) and three plates called SB6 (sandblasted particle plates). The plates were weighed before and after spreading. Once the six plates had been spread, they were placed in a thermostat in the dark at 25°C for 30 minutes. The measurements were performed using a Labsphere UV-1000S spectrophotometer. Nine measurements were performed for each plate, then analyzed using an Excel spreadsheet, providing the SPF and UVAPF values of the measured compositions.

[0105] [Table 4]

[0106] The results show an increase in the in vitro SPF of 46.4% for the formulation according to the application.

[0107] Conclusion: The composition according to the application makes it possible to increase the SPF relative to a comparative oily composition containing the same amount of the same Ti02.

[0108] Example 3: Comparison between the composition according to the application and a comparative composition comprising non-surface-treated nano-TiO2 8.2% by weight of active material (TiO2) with respect to the total weight of the composition due to the surface treatment The two formulations tested were prepared as described in Example 1.

[0109]

[0110] * Evaluation and results: In vitro SPF evaluation The deposit resistance evaluations (dry rubbing, water + dry cloth rubbing and oil + dry cloth rubbing) were measured according to the same protocol as Example 1.

[0111] The results are as follows:

[0112] Conclusion: The amount of nano-TiO2 in the formulation of the present application (8.2 wt% nano-TiO2) is lower compared to the comparative composition (10 wt% nano-TiO2) and the dry and water rub are improved due to the surface treatment of the TiO2 according to the present application.

[0113] The comparative composition is neither resistant to dry rub nor to water rub.

[0114] ​ The in vitro SPF was evaluated according to the same protocol as for example 2.

[0115] The results are as follows:

[0116] Conclusion: The results show an increase of 78% of the in vitro SPF for the composition according to the present application.

[0117] The comparative composition allows a higher filtering under UVAPF.

Claims

1. A cosmetic composition, particularly for cosmetic and / or skin care and / or lip treatment, comprising, in a physiologically acceptable aqueous medium: a) At least 0.01% by weight of natural chitosan with a molecular weight strictly greater than 3000 Daltons, relative to the total weight of the composition, and the amount is strictly less than 15% by weight. b) At least one surface-treated mineral pigment having a size of less than or equal to 100 nm.

2. The composition according to claim 1, wherein, The natural chitosan has a molecular weight greater than or equal to 10 kDa, preferably greater than or equal to 15 kDa, and more preferably greater than or equal to 20 kDa; more preferably, the natural chitosan has a molecular weight between 10 kDa and 2 MDa, more preferably between 15 kDa and 1.5 MDa, more preferably between 20 kDa and 300 kDa, and more preferably between 20 kDa and 200 kDa.

3. The composition according to claim 1 or 2, wherein, The natural chitosan has an acetylation degree of less than or equal to 80%, preferably less than or equal to 70%, preferably less than or equal to 60%, preferably less than or equal to 50%, preferably less than or equal to 35%, preferably less than or equal to 25%, and preferably less than or equal to 15%.

4. The composition according to any one of the preceding claims, wherein, The natural chitosan is a polysaccharide prepared from fungal sources, preferably derived from the mycelium of ascomycete fungi, and especially from Aspergillus niger ( Aspergillus niger ), and / or basidiomycete fungi, and especially shiitake mushrooms ( Lentinula edodes ) and / or button mushrooms ( Agaricus bisporus Preferably, the fungus is Aspergillus niger.

5. The composition according to any one of the preceding claims, wherein, The natural chitosan is present in an amount ranging from 0.01% to 14% by weight, preferably 0.1% to 14% by weight, preferably 0.1% to 12% by weight, preferably 0.2% to 7% by weight, and preferably 0.25% to 5% by weight, relative to the total weight of the composition.

6. The composition according to any one of the preceding claims, wherein the composition comprises, relative to the weight of the composition, 1% to 70% by weight, preferably 1% to 60% by weight, preferably 1% to 50% by weight, preferably 3% to 45% by weight, preferably 4% to 30% by weight, preferably 6% to 20% by weight, preferably 6% to 15% by weight of treated mineral pigment.

7. The composition according to any one of the preceding claims, wherein, The mineral pigment is titanium dioxide.

8. The composition according to any one of the preceding claims, wherein, The mineral pigment is characterized by a size of D[50] less than 100 nm, preferably less than 50 nm, preferably between 5 nm and 40 nm, and preferably between 10 nm and 30 nm, wherein D[50] represents the maximum size of 50% by volume of the particles.

9. The composition according to any one of the preceding claims, wherein, The pigment is treated with a hydrophobic surface treatment agent, which is preferably selected from fatty acids, metal salts, and mixtures thereof; preferably, the surface treatment agent is a mixture of fatty acids and metal salts, more preferably a mixture of stearic acid and aluminum hydroxide.

10. The composition according to any one of the preceding claims, wherein, The surface-treated pigment is titanium dioxide treated with aluminum hydroxide and stearic acid.

11. The composition according to any one of the preceding claims, wherein, The physiologically acceptable aqueous medium comprises, relative to the total weight of the composition, at least 5% by weight, preferably at least 10% by weight, preferably at least 20% by weight, preferably at least 30% by weight, preferably at least 40% by weight of water; preferably 5% to 95% by weight, more preferably 10% to 85% by weight, even more preferably 20% to 80% by weight, even more preferably 25% to 70% by weight, even more preferably 28% to 60% by weight, even more preferably 30% to 50% by weight of water; and optionally at least one organic solvent miscible with water at 25°C, said organic solvent being selected from alcohols, polyols, and mixtures thereof.

12. The composition according to any one of the preceding claims, wherein the composition comprises at least one α-hydroxy acid, preferably the at least one α-hydroxy acid selected from lactic acid, citric acid, methyl lactic acid, glucuronic acid, glycolic acid, pyruvic acid, 2-hydroxybutyric acid, 2-hydroxyvalerate, 2-hydroxyhexanoic acid, 2-hydroxyheptanoic acid, 2-hydroxyoctanoic acid, 2-hydroxynonanoic acid, 2-hydroxydecanoic acid, 2-hydroxyundecanoic acid, 2-hydroxydodecanoic acid, 2-hydroxytetradecanoic acid, 2-hydroxyhexadecanoic acid, 2-hydroxyoctadecanoic acid, 2-hydroxytetracosanoic acid, 2-hydroxyeicosanoic acid, mandelic acid, phenyllactic acid, gluconic acid, galacturonic acid, tung oil acid, ribonucleic acid, hydroxymalonic acid, tartaric acid, malic acid; fumaric acid; their salts and mixtures thereof.

13. The composition according to any one of the preceding claims, wherein the composition has a pH of less than or equal to 7, preferably less than or equal to 6.5, preferably less than or equal to 6.3, preferably between 3 and 6.3, and preferably between 4 and 6.

3.

14. The composition according to any one of the preceding claims, wherein the composition is substantially free of (meth)acrylic polymers and / or silicones; preferably, the composition contains less than 1% by weight, preferably less than 0.5% by weight, preferably less than 0.3% by weight, preferably 0.1% by weight of (meth)acrylic polymers relative to the total weight of the composition, preferably, the composition is completely free of (meth)acrylic polymers; preferably, the composition contains less than 1% by weight, preferably less than 0.5% by weight, preferably less than 0.3% by weight, preferably 0.1% by weight of silicone relative to the total weight of the composition, preferably, the composition is completely free of silicones.

15. The composition according to any one of the preceding claims, characterized in that, The weight ratio between the nano-surface treated mineral pigment and chitosan (i.e., the weight ratio of pigment to chitosan) is greater than 1, preferably between 1 and 30, more preferably between 1 and 25, and more preferably between 5 and 20.

16. A method for applying cosmetics and / or care to skin and / or skin appendages, wherein, The composition according to any one of the preceding claims is applied to the skin and / or skin appendages.

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