FR2902330A1 - Cosmetic use an amphiphilic block copolymer comprising a hydrophobic polymer block of polystyrene and poly (tert-butylstyrene) and a non-ionic hydrophilic polymer block of poly ethylene oxide as keratinous materials i.e. skin moisturizer - Google Patents

Abstract

Cosmetic use an amphiphilic block copolymer comprising a hydrophobic polymer block of polystyrene and poly (tert-butylstyrene) and a non-ionic hydrophilic polymer block of poly ethylene oxide as a moisturizer for keratinous materials, preferably skin.

Description

USE OF AMPHIPHILIC TYPE BLOCK COPOLYMERS

  The present application relates to the use of amphiphilic block copolymers of the polystyrene-polyethylene oxide type as hydrating agents for keratin materials and more particularly for the skin. BACKGROUND OF THE INVENTION

  The Stratum Corneum is the thin stratum corneum that forms the interface between the body and the drying environment. It is formed of the upper epithelial tissue: the epidermis, and connective tissue located below: the dermis. The Stratum Corneum, about 10 to 15 m thick, consists of vertically stacked corneocytes surrounded by a matrix of lipids organized in lamellar liquid crystal phase. Thus, it is a two-compartment system that can be compared to a brick wall, consisting of anucleate cells (bricks) and intercellular lamellar liquid crystal phases (cement).

  One of the functions of the Stratum Corneum is to regulate the flow of water into and out of the skin and thus to delay the excessive loss of water from the deeper layers of the epidermis. The Stratum Corneum also protects against mechanical aggression and the passage of chemicals and foreign microorganisms. It is also the first defense against UV radiation. In general, a moisturizing agent is defined as a substance that decreases the feeling of dry skin by affecting the water content of the skin by addition or retention.

  Generally, corneometry is the method used to measure the hydration provided by humectants such as glycerol, urea and its derivatives. But this method can not be used to highlight the moisturizing properties of polymers, so it was necessary to develop a suitable method to highlight the moisturizing properties of polymers. Different methods based on spectroscopic techniques (infrared, Raman, NMR, etc.) have been developed in recent years with the aim of improving the knowledge of the skin, in particular in the medical field. These techniques have the advantage of not requiring any special preparation of the sample and are non-invasive and non-destructive. These methods are described in particular in: 1. K. Wichrowski, G. Sore, and A. Khaiat, "Use of infrared spectroscopy for in vivo measurement of stratum corneum moisturization after application of cosmetic preparations," Int. J. Cos. Sci. 17, 1-11 (1995). 2. Querleux B, Richard S, Bittoun J, Jolivet O, Idy-peretti I, Bazin R, Lévêque JL: In vivo hydration profile in skin layers by highresolution magnetic resonance imaging. Skin Pharmacol 1994; 7: 210-216. 3. B. Schrader, B. Dippel, S. Fendel, S. Keller, T. Lochte, M. Riedl, R. Schulte, and E. Tatsch, "NIR FT Raman Spectroscopy, a new tool in medical diagnosis," J. mol. Struct. 408/409, 23-31 (1997). In the context of the present application, the method adopted for measuring the amount of water supplied by polymer solutions at 1% by weight is laser confocal microscopy associated with Raman spectroscopy. Raman spectroscopy provides information on the molecular composition and structure of the test sample. Associated with confocal microscopy, it offers the advantage of providing information on the Stratum Corneum from the surface of the skin to a depth of a few tens of microns. In addition, the method used in this application has the advantage of being non-invasive and non-destructive.

  This method has established that the polymers used in accordance with the present application are such that a 1% solution by weight of these polymers makes it possible to provide a water content at least equal to that provided by a 7% solution. % by weight of glycerol.

  To implement this method, Isolated Stratum Corneum, compacted Stratum Corneum dander pellets, artificial skin (Episkin, Matek, Skinethic ...) from cosmetic surgery skin can be used as an evaluation support. . These examples are not limiting, all the media modeling the skin can be used. In the context of the present application, compacted dander pellets having a weight of 80 to 100 mg, a thickness of more than 100 μm and a surface area of approximately 1 cm 2 are used as a Stratum Corneum model; 5 measurements are made on each plantar pellet and 5 pellets are used for each polymer solution, 25 measurements for each polymer solution. The amount of polymer solution applied to each pellet is about 500. A Raman laser confocal microscope of LabRam type (Jobin Yvon to Horiba) equipped with a He: Ne laser (k 633 nm of power of approximately 8.4 mW) and a CCD detector is used to perform the measurements. The laser beam is focused in the skin with an X50 objective and the Raman spectra are recorded using a point-to-point mode, from the sample surface, to the depth. The acquisition parameters of the spectra are: hole and slit: 20011m, acquisition time: 30s on a frequency of 2800 to 4000 cm -1. The microscope in question was the subject of a technical modification essential to the measurement of water, with the incorporation of a chamber allowing to control during the acquisitions the temperature and the humidity: the parameters are of 25 C and 50% relative humidity Quantization of the water is determined by the ratio of the OH bands of the water / CH3 bands of the proteins, in Raman spectrography, as described in: 1 Chrit L, Hadjur C, Morel S, Sockalingum GD, Lebourdon G, Leroy F, Manfait M: In In vivo chemical investigation of Human skin using a confocal Raman Optic microprobe, J. Biomed Opt 2005. 2 Caspers PJ, Lucassen GW, EA Carter, Bruining HA, Puppels GJ: In vivo confocal Raman microspectroscopy of the skin: noninvasive determination of molecular concentration Journal of Investigative Dermatology 2 001; 116 (3): 434-442.

  The water / protein ratios in the Stratum Corneum were determined in Raman spectrography, by calculating the ratio between the intensity of the OH bands of the water (area under the curve) integrated between 3350cm "'and 3550 cm-1 and the Intensity of the protein CH3 bands (area under the curve) integrated between 2910cm- 'and 2965 cm-1.

  Quantification of water is calculated from the following equations

  W / P = (m ,,, / mp) R Water content (%): mw, / (mW, + mp) -100% (W / P) / (W / (P + R)) 20 m, ,, and mp respectively being the masses of water and protein in the volume of the tested sample W being the intensity of the Raman signal of the integrated water (integrated OH bands of the water (area under the curve)) ; Where P is the intensity of the integrated protein Raman signal (embedded protein CH3 (area-under-the-curve) bands); R is a proportionality constant expressing the ratio between the Raman signals of water and proteins in a 50% solution. The water content is expressed in grams of water per 100 grams of wet tissue. These features are integrated into Jobin-Yvon Horiba's LabSpec software.

  To evaluate the moisturizing performance, the measurements are made at T = 0, before the treatment and at T + 1 hour after the treatment, the surface at 201.tm depth. The problem posed by the present application was to propose families of compounds that can be used as moisturizing agents for keratin materials and more particularly for the skin. The inventors of the present application have shown that this problem can be solved by means of amphiphilic block copolymers comprising a hydrophobic polymeric block chosen from polystyrene and poly (tert.-butylstyrene) and a nonionic hydrophilic block which is polyoxyethylene oxide. The present invention therefore relates to the cosmetic use of at least one amphiphilic block copolymer comprising a hydrophobic polymeric block chosen from polystyrene and poly (tert-butylstyrene) and a nonionic hydrophilic block which is the polyethylene oxide as a moisturizing agent of keratin materials and more particularly of the skin. Preferably, the hydrophobic polymeric block is polystyrene. Amphiphilic block copolymers comprising a hydrophobic polymeric block selected from polystyrene and poly (tert.-butylstyrene) and a nonionic hydrophilic block which is polyethylene oxide have been found to be more moisturizing than glycerol. Amphiphilic block copolymers comprising a hydrophobic polymeric block chosen from polystyrene and poly (tert-butylstyrene) and a nonionic hydrophilic block which is polyethylene oxide which can be used in the context of the present application may be used alone or in mixtures . In particular, the copolymers used according to the invention consist of a hydrophobic block and a hydrophilic block as described above. Advantageously, the amphiphilic block copolymers used in the present application have the property of forming, in contact with water, micelles, and in particular very stable micelles leading to transparent suspensions. The amphiphilic block copolymers used in the present application are diblocks (hydrophobic polymeric block -non ionic hydrophilic polymeric block), their average molecular weight may be between 1,000 and 100,000, the weight ratio hydrophobic polymeric block / nonionic hydrophilic polymeric block can be between 1/100 and 50/1. The amphiphilic block copolymer is preferably chosen from the following block copolymers: polystyrene / polyoxyethylene, poly (tert-butylstyrene) / polyoxyethylene, for example, Tegomer SE 1010 (polystyrenepolyoxyethylene 1000/1000, that is, the molecular weight of the polystyrene is 1000 and the molecular weight of the polyoxyethylene is 1000) and Tegomer SE 1030 (polystyrene-polyoxyethylene 1000/3000, that is, the molecular weight of the polystyrene is 1000 and the Molecular weight of polyoxyethylene is 3000) marketed by DEGUSSA.

  These amphiphilic block copolymers are conventionally obtained from polystyrene according to the reaction scheme: ## STR1 ## The inventors of the present application have shown that the polymers used in accordance with the present application are such that 1% solution by weight of these polymers makes it possible to provide a quantity of water in the Stratum Corneum at least equal to that provided by a solution containing 7% by weight of glycerol. As part of the present application, amphiphilic block copolymers comprising a hydrophobic polymeric block selected from polystyrene and poly (tert.-butylstyrene) and a nonionic hydrophilic block which is polyethylene oxide can be used in cosmetic compositions in an amount of between 0.01% and 20% by weight, preferably between 0.1% and 10% by weight relative to the total weight of said composition. The cosmetic compositions that can be used contain a physiologically acceptable medium, that is to say compatible with cutaneous tissues such as the skin and the scalp. This physiologically acceptable medium may more particularly consist of water and optionally of a physiologically acceptable organic solvent chosen, for example, from lower alcohols containing from 1 to 8 carbon atoms and in particular from 1 to 6 carbon atoms, such as ethanol, isopropanol, propanol, butanol; polyethylene glycols having from 6 to 80 ethylene oxide units and polyols such as propylene glycol, isoprene glycol, butylene glycol, glycerine and sorbitol. The compositions which may be used may be the galenical forms conventionally used for a topical and in particular in the form of hydroalcoholic solutions, oil-in-water (O / W) or (W / O) or multiple (triple: W / O / W) emulsions. E or H / E / H), dispersing gels of a fatty phase in a spherical phase, these spherules possibly being polymeric nanoparticles such as nanospheres and nanocapsules or lipid vesicles of ionic and / or nonionic type (liposomes , niosomes, oleosomes). These compositions are prepared according to the usual methods. In addition, the compositions that can be used can be more or less fluid and have the appearance of a white or colored cream, an ointment, a milk, a lotion, a serum, a paste or of a foam. They may optionally be applied to the skin in the form of an aerosol. They may also be in solid form, for example in the form of a stick. When the composition that can be used according to the invention comprises an oily phase, the latter preferably contains at least one oil. It may also contain other fatty substances. As oils that can be used in the composition of the invention, mention may be made, for example, of: hydrocarbon-based oils of animal origin, such as perhydrosqualene; Hydrocarbon oils of vegetable origin, such as liquid triglycerides of fatty acids containing from 4 to 10 carbon atoms, such as triglycerides of heptanoic or octanoic acids, under any aqueous application, aqueous water-in-oil, or aqueous with or, for example, sunflower, corn, soya, squash, grape seed, sesame, hazelnut, apricot, macadamia, arara, castor oil, avocado, caprylic / capric acid triglycerides such as those sold by Stearineries Dubois or those sold under the names Miglyol 810, 812 and 818 by Dynamit Nobel, jojoba oil, shea butter oil; esters and synthetic ethers, in particular of fatty acids, such as the oils of formulas R 1 COOR 2 and R 1 OR 2 in which R 1 represents the residue of a fatty acid comprising from 8 to 29 carbon atoms, and R 2 represents a hydrocarbon-based chain, branched or unbranched, containing from 3 to 30 carbon atoms, such as for example purcellin oil, isononyl isononanoate, isopropyl myristate, 2-ethylhexyl palmitate, octyl stearate -2-dodecyl, octyl-2-dodecyl erucate, isostearyl isostearate; hydroxylated esters such as isostearyl lactate, octyl hydroxystearate, octyldodecyl hydroxystearate, diisostearyl malate, triisocetyl citrate; heptanoates, octanoates, decanoates of fatty alcohols; polyol esters, such as propylene glycol dioctanoate, neopentyl glycol diheptanoate and diethylene glycol diisononanoate; and pentaerythritol esters such as pentaerythrityl tetraisostearate; linear or branched hydrocarbons of mineral or synthetic origin, such as paraffin oils, volatile or not, and their derivatives, petroleum jelly, polydecenes, hydrogenated polyisobutene such as parleam oil; fatty alcohols having from 8 to 26 carbon atoms, such as cetyl alcohol, stearyl alcohol and their mixture (cetylstearyl alcohol), octyldodecanol, 2-butyloctanol, 2-hexyldecanol, 2-undecylpentadecanol, oleic alcohol or linoleic alcohol; partially fluorinated hydrocarbon oils and / or silicone oils such as those described in document JP-A-2-295912; silicone oils such as volatile or non-volatile polymethylsiloxanes (PDMS) with a linear or cyclic silicone chain, which are liquid or pasty at room temperature, in particular cyclopolydimethylsiloxanes (cyclomethicones) such as cyclohexasiloxane; polydimethylsiloxanes comprising alkyl, alkoxy or phenyl groups, during or at the end of the silicone chain, groups having from 2 to 24 carbon atoms; phenyl silicones such as phenyltrimethicones, phenyldimethicones, phenyltrimethylsiloxydiphenylsiloxanes, diphenyl-dimethicones, diphenylmethyldiphenyltrisiloxanes, 2-phenylethyltrimethylsiloxysilicates, and polymethylphenylsiloxanes; their mixtures. By hydrocarbon oil is meant in the list of oils mentioned above, any oil predominantly comprising carbon and hydrogen atoms, and optionally ester, ether, fluoro, carboxylic acid and / or alcohol groups. The other fatty substances that may be present in the oily phase are, for example, fatty acids containing from 8 to 30 carbon atoms, such as stearic acid, lauric acid, palmitic acid and oleic acid; waxes such as lanolin, beeswax, carnauba or candelilla wax, paraffin waxes, lignite waxes or microcrystalline waxes, ceresin or ozokerite, synthetic waxes such as polyethylene waxes, waxes Fischer-Tropsch; silicone resins such as trifluoromethyl-C 1-4 alkyl dimethicone and trifluoropropyldimethicone; and silicone elastomers such as the products sold under the names KSG by the company Shin-Etsu, under the names Trefil, BY29 or EPSX by the company Dow Corning or under the names Gransil by the company Grant Industries. These fatty substances may be chosen in a varied manner by those skilled in the art in order to prepare a composition having the desired properties, for example of consistency or texture. The emulsions generally contain at least one emulsifier chosen from amphoteric, anionic, cationic or nonionic emulsifiers, used alone or as a mixture, and optionally a co-emulsifier. The emulsifiers are suitably selected according to the emulsion to be obtained (W / O or O / W). The emulsifier and the co-emulsifier are generally present in the composition, in a proportion ranging from 0.3 to 30% by weight, and preferably from 0.5 to 20% by weight relative to the total weight of the composition. For the W / O emulsions, examples of emulsifiers that may be mentioned include dimethicone copolyols such as the mixture of cyclomethicone and dimethicone copolyol, sold under the name DC 5225 C by the company Dow Corning, and alkyl dimethicone copolyols such as Laurylmethicone copolyol sold under the name Dow Corning 5200 Formulation Aid by the company Dow Corning and cetyl dimethicone copolyol sold under the name Abil EM 90 by the company Goldschmidt. It is also possible to use, as surfactant of W / O emulsions, a crosslinked solid elastomeric organopolysiloxane comprising at least one oxyalkylene group, such as those obtained according to the procedure of Examples 3, 4 and 8 of US Pat. No. 5,412,004 and examples US-A-5,811,487, especially the product of Example 3 (synthetic example) of US-A-5,412,004. and such as that sold under the reference KSG 21 by Shin Etsu. For O / W emulsions, mention may be made, for example, as emulsifiers, of nonionic emulsifiers such as oxyalkylenated (more particularly polyoxyethylenated) fatty acid esters of glycerol; oxyalkylenated fatty acid and sorbitan esters; oxyalkylenated fatty acid esters (oxyethylenated and / or oxypropylenated); oxyalkylenated fatty alcohol ethers (oxyethylenated and / or oxypropylenated); sugar esters such as sucrose stearate; and mixtures thereof such as the mixture of glyceryl stearate and PEG-40 stearate. In known manner, the cosmetic or dermatological compositions that may be used may also contain adjuvants that are customary in the cosmetic or dermatological field, such as gelling agents, film-forming polymers, preservatives, solvents, perfumes, fillers, UV filters, bactericides. odor absorbers, dyestuffs, plant extracts and salts. The amounts of these various adjuvants are those conventionally used in the field under consideration, and for example from 0.01 to 20% of the total weight of the composition. These adjuvants, depending on their nature, can be introduced into the fatty phase and / or into the aqueous phase.

  In the context of cosmetic compositions, amphiphilic block copolymers comprising a hydrophobic polymeric block chosen from polystyrene and poly (tert.-butylstyrene) and a nonionic hydrophilic block which is polyethylene oxide may be combined with one another, or other additional skin hydrating agents and / or at least one other cosmetic active. As such an additional cosmetic asset, there may be mentioned the active agents acting on the barrier function of the skin, the active agents promoting the hydration of the skin and the desquamating agents. In the context of dermatological compositions, amphiphilic block copolymers comprising a hydrophobic polymeric block chosen from polystyrene and poly (tert.-butylstyrene) and a nonionic hydrophilic block which is polyethylene oxide may be associated with one another, or with other additional skin hydrating agents and / or at least one other active agent, this active ingredient may be cosmetic or dermatological. As such an additional asset, there may be mentioned active agents acting on the barrier function of the skin, the active agents promoting the hydration of the skin and the desquamating agents. By desquamating agent is meant any compound capable of acting: either directly on desquamation by promoting exfoliation, such as (3-hydroxyacids, in particular salicylic acid and its derivatives (including n-octanoyl 5-salicylic acid), α-hydroxyacids, such as glycolic, citric, lactic, tartaric, malic or mandelic, urea, gentisic acid, oligofucoses, cinnamic acid, Saphora japonica extract, resveratrol, or enzymes involved in desquamation or degradation of corneodesmosomes, such as glycosidases, Stratum Corneum chymotryptic enzym (SCCE) or even other proteases (trypsin, chymotrypsin-like) .Choose inorganic salt chelating agents: EDTA; N-acyl acid; -N, N ', N' diaminetriacetic thylene; aminosulfonic compounds and in particular N- (2-hydroxyethyl) piperazine-N'-2-ethanesulfonic acid (HEPES); 2-oxothiazolidine-4-carboxylic acid derivatives (procysteine); glycine-type alpha amino acid derivatives (as described in EP-0 852 949, as well as the sodium methyl glycine diacetate marketed by BASF under the trade name TRILON M); honey ; sugar derivatives such as O-octanoyl-6-D-maltose and N-acetyl glucosamine.

  Among the active agents acting on the barrier function of the skin, or promoting the hydration of the skin, mention may be made of: - either the compounds acting on the barrier function, with a view to maintaining the hydration of the Stratum Corneum, or the occlusive compounds , in particular ceramides, sphingoid-based compounds, lecithins, glycosphingolipids, phospholipids, cholesterol and its derivatives, phytosterols (stigmasterol, 13-sitosterol, campesterol), essential fatty acids, 1-2 diacylglycerol, 4-chromanone, pentacyclic triterpenes such as ursolic acid, petrolatum and lanolin; or compounds directly increasing the water content of Stratum Corneum, such as thralose and its derivatives, hyaluronic acid and its derivatives, glycerol, pentanediol, sodium pidolate, serine, xylitol, lactate sodium, glycerol polyacrylate, ectoin and its derivatives, chitosan, oligo- and polysaccharides, cyclic carbonates, N-lauroyl pyrrolidone carboxylic acid, and Na-benzoyl-L-arginine; or compounds that activate the sebaceous glands, such as steroid derivatives (including DHEA) and vitamin D and its derivatives. The compositions can show their effectiveness as a non-therapeutic skin care treatment, that is, as a preventive measure. They can also be used as a non-therapeutic treatment of the skin after a manifestation of disorders of the hydration of the skin. The composition may be presented as a non-therapeutic care product and / or makeup, and also a lip balm.

  Amphiphilic block copolymers comprising a hydrophobic polymeric block chosen from polystyrene and poly (tert.-butylstyrene) and a nonionic hydrophilic block which is polyethylene oxide may also be used in or for the implementation of a process cosmetic treatment for the non-therapeutic care and / or for the make-up of the skin, characterized in that it comprises the application to the skin of at least one cosmetic composition according to the present invention comprising at least one amphiphilic block copolymer comprising a hydrophobic polymeric block selected from polystyrene and poly (tert.-butylstyrene) and a nonionic hydrophilic block which is polyethylene oxide as defined above or a mixture thereof in all proportions. Among the makeup type applications that the cosmetic treatment process makes it possible to envisage, mention may be made of foundations, blushers, eyeshadows, concealer and body make-up. Amphiphilic block copolymers comprising a hydrophobic polymeric block chosen from polystyrene and poly (tert.-butylstyrene) and a nonionic hydrophilic block which is polyethylene oxide as defined above or from a mixture thereof may also be used. be used for the preparation of a dermatological composition intended for the hydration of the skin and more particularly to the treatment of dry skin or the treatment of dry skin.

  The following examples are given by way of illustration of the present invention, and can not limit the scope thereof. Examples The moisturizing performance of the following solutions was tested. 93% Solution A Distilled water Glycerol 7% Solution B 99% Distilled water Tegomer SE 1010 (PS-POE 1000/1000) 1% Solution C 99% Distilled water Tegomer SE 1030 (PS-POE 1000/3000) 1% 20 25 30 Moisture Performance Solution Measured by Confocal Raman Laser Confocal Microscopy Method A 1 B 1.57 C 1.53 Significantly, amphiphilic block copolymers comprising a hydrophobic polymeric block which is polystyrene and a nonionic hydrophilic block which is polyoxyethylene oxide. ethylene solution in water at 1%, have a moisturizing performance, measured in confocal laser Raman microscopy, higher than that of glycerol at 7% in water.

Sample composition

  The following moisturizing cosmetic composition was carried out: Phase Al: Sucrose distearate (marketed by the company 2.0% "STEARINERIE DUBOIS") Sorbitan stearate oxyethylenated with 4 moles of oxide 1.4% ethylene (marketed under the name "TWEEN 61" by the company ICI) stearic acid 0.75% Stearyl heptanoate (marketed by the company 5.50% DRAGOCO under the name PCL solid) Vaseline codex 2, 1% Avocado oil 4.50 % Jojoba oil 4.10% Volatile silicone oil 3.70% Vitamin E acetate 0.50% Perfume Propylparaben Methyl paraben Triethanolamine Demineralized water Phase A2: Phase B: Phase C: Mix of carboxyvinyl polymers 0.30% (marketed under the name "CARBOPOL 980" by the company GOODRICH) Tegomer SE 1010 (PS-POE 1000/1000) from 2% Degussa Demineralized water 9.70% The two phases Al and B are brought to 65 C before being associated (B in Al) under very vigorous agitation (rotor-stator). After controlling for a perfect dispersion, it is possible, optionally, to homogenize the dispersion between 20 × 10 6 Pascal and 60 × 10 6 Pascal, to obtain a dispersion whose size of the oil globules is less than 500 nm. Phase A2 is dispersed at room temperature Silicone gum (marketed by the company 4.00% Dow Corning under the name "Q2-1403 Fluid") 0.3% 0.1% 0.30% 0.40% q.s. 100.00% in the first dispersion, with vigorous stirring. Phase C, previously prepared, is then dispersed in order to gel the suspension. A moisturizing emulsion suitable for dry skin is obtained. Tegomer SE 1010 contributes to this moisturizing activity.

Claims (6)

  A cosmetic use of at least one amphiphilic block copolymer comprising a hydrophobic polymeric block selected from polystyrene and poly (tert.-butylstyrene) and a nonionic hydrophilic polymeric block which is polyethylene oxide as a hydrating agent for keratin materials, preferably the skin.   2. Cosmetic use according to claim 1 characterized in that the hydrophobic polymeric block is polystyrene.   3. Cosmetic use according to claim 1 or 2, characterized in that the amphiphilic block copolymers are chosen from the following block copolymers: polystyrene / polyoxyethylene, poly (tert-butylstyrene) / polyoxyethylene,   4. Cosmetic use according to one of the preceding claims characterized in that the diblock type amphiphilic block copolymer (hydrophobic polymeric block - nonionic hydrophilic polymeric block) has a molecular weight of between 1000 and 100 000.   5. Cosmetic use according to one of the preceding claims characterized in that the diblock type amphiphilic block copolymer (hydrophobic polymeric block - nonionic hydrophilic polymeric block) has a hydrophobic polymeric block ratio / non ionic hydrophilic polymeric block of between 1/100 and 50/1.   6. Cosmetic use according to one of the preceding claims characterized in that the amphiphilic block copolymer is chosen from polystyrene-polyoxyethylene 1000/1000 and polystyrene-polyoxyethylene 1000/3000.