EMULSIFYING COMPOSITION FOR COSMETIC USE FOR PRODUCING AN OIL-IN-WATER PICKERING EMULSION AND METHOD FOR PRODUCING SAID EMULSION

Description

[0001] The present invention relates to a ready-to-use emulsifying composition of plant origin, which can be used directly in the cold state, and which finds applications in particular in the field of cosmetics. This composition is sufficient in itself and allows an emulsion to be directly stabilized without the necessary addition of a co-emulsifier of petrochemical origin. This emulsifying composition allows in particular the easy production of very fine O / W emulsions with varied textures, very compatible with the skin and also having a dry and fresh, silky and non-greasy feel even with a high content of fatty phase in the emulsion. This composition also makes it possible to advantageously reduce the quantity of emulsifier of natural origin required to obtain an O / W emulsion.

[0002] An emulsion is a dispersion of a liquid (or a material made liquid) in fine droplets in another liquid immiscible with the first. It has a macroscopically homogeneous appearance but appears heterogeneous under the microscope. The liquid in the form of droplets is called the dispersed (or discontinuous) phase, while the other liquid is called the dispersing (or continuous) phase. In general, an emulsion is composed of water and oil and two phases (simple emulsion): a hydrophilic (aqueous) phase and a lipophilic (fatty) phase. The most commonly encountered emulsions are emulsions comprising a lipophilic phase dispersed in a continuous aqueous phase and are called oil-in-water (O / W) emulsions, as opposed to water-in-oil (W / O) emulsions.

[0003] Many cosmetic compositions are emulsions, typically simple emulsions, stabilized by surfactants, also called emulsifiers. For example, document EP 0 685 227 proposes a very complex system of antisun cosmetic compositions, comprising an aqueous continuous phase, a protective system capable of filtering UV rays, a surfactant, organic solvents (alcohols and lower polyols) and at least one polymer or more particularly a crosslinked copolymer (alkyl acrylates, vinyl acetate).

[0004] Document FR 2 858 777 describes an oil-in-water emulsion containing at least one fatty substance (fatty acid esters, waxes, butters, natural oils - vegetable, animal, of marine origin -, synthetic or mineral, hydrogenated oils and their mixtures), at least one surfactant (ethoxylated polyglycerol fatty acid esters, alcohol ethoxylates), at least one co-surfactant and water.

[0005] Document DE 102 39 647 A1 describes cosmetic and / or dermatological oil / water (O / W) emulsions containing (a) an aqueous phase, (b) an oily phase of 0.5 to 10% by weight of non-polar to medium-polar oil(s) with a polarity of 20-60 mN / m, (c) 0.005 to 10% by weight of cyclodextrin derivative(s) and optionally other cosmetic and / or dermatological agents, adjuvants and additives.

[0006] Document EP 3 037 083 A1 describes a sunscreen composition without emulsifier.

[0007] Document FR 2 823 438 A1 describes an oil-in-water emulsion, based on a self-emulsifiable combination of fatty alcohols and glucolipids in a weight ratio of between 10:1 and 4:1, and it is distinguished in that it also comprises a viscosity-increasing agent in the fatty phase.

[0008] However, the use of surfactants in products intended for application to humans or animals, whether in topical, oral, or other forms, can be problematic. Indeed, surfactants can damage cell membranes. Thus, efforts are being made, particularly in the cosmetic field, to reduce the potentially harmful effects of surfactants, or even eliminate the use of surfactants.

[0009] Also, one of the aims of the present invention is to provide an emulsifying composition, which is capable of forming a stable emulsion by adding oil or fatty substances when it is placed in the presence of water, in particular according to a so-called “cold” process.

[0010] Advantageously, this emulsifying composition according to the invention makes it possible to significantly reduce the use of surfactants of petrochemical origin and non-biodegradable, in particular glycol derivatives and ethoxylated or polyethoxylated derivatives. According to another variant, it makes it possible to eliminate the use of these surfactants of petrochemical origin.

[0011] From this point of view, the composition according to the present invention also makes it possible to manufacture Pickering type emulsions. Emulsions of this type are free of surfactant and are stabilized by colloidal particles such as silicas which are usually placed at the interfaces of the continuous phase and the dispersed phase. In the context of the present invention, these colloidal particles are organic particles consisting of inclusion complexes between at least one cyclodextrin and at least one fatty molecule. These particles are very advantageously compatible with the skin or hair and do not damage animal cell membranes.

[0012] This result is all the more remarkable since the state of the art demonstrates that the manufacture of emulsifying systems for cosmetic use and containing cyclodextrins does not allow emulsions to be obtained easily and directly in the cold: it was necessary until now to use conventional surfactants operating at high temperature and generally of petroleum origin. This is particularly what is reported in document EP 2 091 502 B1 (WO 2008 / 003685 A1) which describes an O / W emulsion containing water, a fatty substance, a modified polysaccharide, and a cyclodextrin, the essential characteristic of this O / W emulsion being that it contains surfactants with a molecular weight of less than 5,000 g / mol and in an amount of less than 2% by weight.It was therefore not known, nor obvious, how to produce emulsifying systems containing cyclodextrins that would allow very fine and very stable emulsions to be obtained without resorting to ordinary surfactants of petrochemical origin.

[0013] Another object of the present invention is to provide a composition of natural origin. The natural origin of the ingredients used to formulate commonly used products such as cosmetic compositions is today a major issue, not only with regard to the safeguarding and protection of our environment but also for the well-being of consumers. As such, the composition according to the present invention makes it possible to reduce, or even replace, traditional emulsifiers, in particular ethoxylated emulsifiers, which we are currently seeking to replace for environmental reasons (poor biodegradability) and safety reasons (ethylene oxide is toxic and flammable).

[0014] Another object of the present invention is to provide a ready-to-use emulsifying composition, allowing the formulator a very simple implementation, with a minimal energy input, in particular by introducing all the ingredients into the same tank or reactor (formulation known as "one pot" in English language). From the point of view of its implementation, the composition which is the subject of the present invention can advantageously be used according to a "cold process", that is to say even at room temperature, unlike many conventional solid or pasty emulsifiers such as waxes which require an increase in temperature for their implementation (ingredient requiring to be melted and usable "hot"). The notion of cold process includes emulsification processes in which the only heat input is that due to the dissipation of energy caused by mechanical stirring.By "cold process" is meant that the emulsifying composition can be implemented directly by dispersion in water at a water temperature below 45°C, better still below 35°C, and better still at room temperature.

[0015] Another object of the present invention is to provide a broad-spectrum emulsifying composition for cosmetic use, i.e. versatile from the point of view of the final products envisaged: from this point of view, the composition according to the invention can be used in products as diverse as lotions, creams, gels, milks, etc. Furthermore, said composition is advantageously non-irritating and non-allergic to the skin. It also offers the advantage of not depending on the pH or the presence of electrolytes: in other words, its emulsifying capacity is not affected by the pH of the medium, nor by the presence of mono-, di- or trivalent salts. This criterion is all the more important since, in general, products for cosmetic use and in particular for topical application are likely to be subjected to or exposed to pH variations (for example, the pH of the skin is slightly acidic, and varies between 4 and 6).Having a product that does not have any particular usage limits in terms of pH therefore represents a very great technical advantage for a cosmetic composition.

[0016] Finally, another object of the present invention is to provide a composition for cosmetic use, offering a wide range of sensory properties of interest, such as in particular a sensation of freshness at the level of the epidermis or a creamy texture. Indeed, the emulsifying composition according to the invention allows the easy production of O / W emulsions which are both very stable and very fine, with adjustable textures and having a fresh, silky and non-greasy feel, even for high contents of dispersed fatty phase. It is thus possible to obtain emulsions having a good emollient effect on the skin as well as a good moisturizing effect on the upper layers of the epidermis.

[0017] All of these objectives, which constitute a complex technical problem to solve, are finally achieved thanks to the main object of the present invention, defined in claim 1, which consists of an emulsifying composition, in particular for cosmetic use, capable of allowing the production of an oil-in-water (O / W) type emulsion, comprising: a. at least one cyclodextrin, b. and at least one O / W emulsifier, wherein the O / W emulsifier is a mixture of at least one C12-C20 alkyl polyglucoside and at least one linear or branched fatty alcohol having a total number of carbon atoms ranging from 8 to 24,

[0018] the H / W emulsifier having a Hydrophilic-Lipophilic balance (HLB) greater than 8, preferably greater than or equal to 9.

[0019] The invention is also defined by claims 2 to 15.

[0020] An emulsifying composition is also described, in particular for cosmetic use, capable of allowing the production of an oil-in-water (O / W) type emulsion, comprising 1) at least one cyclodextrin, 2) and at least one H / W emulsifier of natural origin.

[0021] the H / W emulsifier having a Hydrophilic-Lipophilic balance (HLB) greater than 8, preferably greater than or equal to 9.

[0022] The calculation of HLB takes into account the molecular masses of the hydrophilic parts and the molecular mass of the molecule considered and can be obtained according to the following equation: HLB = 20 Masse moléculaire partie hydrophile Masse moléculaire de la molécule

[0023] In this Application, the term "cyclodextrin" means and includes any of the cyclodextrins otherwise known, such as native and unsubstituted cyclodextrins containing from 6 to 12 glucose units linked by covalent bonds between carbons 1 and 4, and in particular alpha-, beta- and gamma-cyclodextrins containing 6, 7 and 8 glucose units respectively.

[0024] This term also covers "cyclodextrin derivatives", namely molecules in which at least some of the OH hydroxyl groups have been transformed into OR groups, where R generally denotes an alkyl group. From this point of view, cyclodextrin derivatives include in particular methylated and ethylated cyclodextrins, but also those substituted with a hydroxyalkyl group such as hydroxypropylated and hydroxyethylated cyclodextrins.

[0025] Preferred cyclodextrins according to the present disclosure are alpha-, beta-, and gamma-cyclodextrins, with native beta-cyclodextrin being most preferred.

[0026] Cyclodextrin may in particular be in the form of a crystalline, pseudo-crystalline or amorphous powder.

[0027] In this Application, the term "O / W emulsifier of natural origin" means any molecule derived from renewable resources, in particular extracted or secreted by plants, microorganisms or algae and capable of allowing, after physical, chemical or enzymatic modification, the production of an O / W water-in-oil emulsion or of promoting its stability. This definition therefore includes products called O / W co-emulsifiers of natural origin.

[0028] The Applicant was able to observe after numerous tests and experimental plans, that in a completely surprising and unexpected manner, the association with a cyclodextrin of an emulsifier of natural origin having a Hydrophilic-Lipophilic balance (HLB) greater than 8, preferably greater than or equal to 9, making it possible in a manner known per se to obtain an O / W emulsion, far from having negative consequences on the stability and quality of O / W emulsions, on the contrary has a very favorable effect. It is thus advantageously possible to reduce the quantity of emulsifier of natural origin required to obtain a satisfactory and stable emulsion, and moreover, to finely adjust the texture and sensory profile of the emulsion.

[0029] Without wanting to be bound by any theory, it seems that the presence of very small quantities of a naturally occurring O / W emulsifier greatly facilitates the in situ formation of inclusion complexes between the cyclodextrin and certain specific molecules present in the dispersed fatty phase, and this in the form of colloidal particles, solid or semi-liquid, which are placed at the oil and water interfaces. These particles are very physically and sensorially compatible with the skin or hair and do not damage animal cell membranes.

[0030] It has been shown that the combination of cyclodextrin with small amounts of a natural O / W emulsifier with a Hydrophilic-Lipophilic Balance (HLB) greater than 8, preferably greater than or equal to 9, makes it possible to obtain very stable emulsions with droplets of size less than 30 µm, or even less than 10 µm. It has also been shown that this addition makes it possible to adjust the final viscosity of the O / W emulsion. Thanks to this viscosity adjustment, combined with the droplet size of less than 30 µm, or even 10 µm, the texture of the emulsions can be advantageously adjusted.

[0031] The H / W emulsifier of natural origin having a Hydrophilic-Lipophilic balance (HLB) greater than 8, preferably greater than or equal to 9, is preferably present in the emulsifying composition in a ratio of between 0.01 and 1 part, preferably between 0.05 and 0.5 part, more preferably between 0.10 and 0.35 part, and better still between 0.15 and 0.30 part, per 1 part by weight of cyclodextrin.

[0032] This natural O / W emulsifier can also be chosen from products that are naturally biodegradable in a hydrated natural environment, with a Hydrophilic-Lipophilic Balance (HLB) of between 8 and 20, preferably between 9 and 16, and even better between 11 and 14.

[0033] By way of example, this O / W emulsifier of natural origin as described in the present application may be chosen from the following products, provided that they satisfy the condition on the HLB above: alkyl polyglucosides; mixtures of at least one alkyl polyglucoside and at least one fatty alcohol; non-ethoxylated fatty esters of polyols, and in particular from among the non-ethoxylated fatty esters of glycerol, polyglycerols, sorbitol, sorbitan, anhydrodrohexitols such as in particular isosorbide, mannitol, xylitol, erythritol, maltitol, sucrose, glucose, polydextrose, hydrogenated glucose syrups, dextrins and hydrolyzed starches.

[0034] The O / W emulsifier of natural origin as described in the present application is preferably chosen to be naturally biodegradable in a hydrated natural environment. It may in particular be non-ethoxylated fatty esters of polyols obtained from fatty acid or by transesterification from oil or mixtures of oils. The fatty acids used comprise from 8 to 22 carbon atoms, preferably from 10 to 18 carbon atoms, and in particular from 12 to 18 carbon atoms. These acids may be linear or branched, saturated or unsaturated, and may have one or more side hydroxyl functions. The oils may be saturated or unsaturated, from liquid to solid at room temperature, and may optionally have hydroxyl functions, preferably with an iodine number of between 1 and 145, and in particular from 5 to 105.

[0035] The O / W emulsifier of natural origin as described in the present application may in particular be chosen from polyglycerol esters, and preferably from esters resulting from the reaction of polyglycerols comprising from 2 to 12 glycerol units, preferably from 3 to 10 glycerol units with at least one partially hydrogenated or non-hydrogenated vegetable oil with an iodine value of between 1 and 15, and in particular from 5 to 10. It may in particular be oleic, stearic, palmitic, lauric, diisostearic and caprylic esters of polyglycerols and in particular the following products: Polyglyceryl-5 Dioleate of HLB approximately 8 (such as Dermofeel ®< G 5 DO from Evonik Dr. Straetmans GmbH), Polyglyceryl-2 Caprate of HLB approximately 9 (such as HYDRIOL ®< PGC.2 from HYDRIOR), Polyglyceryl-3 Stearate of HLB about 9 (as Dermofeel ®< PS from Evonik Dr. Straetmans GmbH), Polyglyceryl-2 Laurate of HLB about 9 (as Dermofeel ®< G2L from Evonik Dr.Straetmans GmbH), Polyglyceryl-3 Palmitate of HLB about 10 (as Dermofeel ®< PP from Evonik Dr. Straetmans GmbH), Polyglyceryl-10 Diisostearate of HLB about 11 (as Dermofeel ®< G10 DI from Evonik Dr. Straetmans GmbH), Polyglyceryl-6 Caprylate of HLB about 11.5, Polyglyceryl-5 Laurate of HLB about 13 (as Dermofeel ®< G5L from Evonik Dr. Straetmans GmbH), Polyglyceryl-3 Caprate of HLB about 14 (as HYDRIOL ®< PGC.3 from HYDRIOR), Polyglyceryl-4 Caprate of HLB about 14 (as MASSOCARE PG4 C from Masso), Polyglyceryl-10 Monolaurate of HLB about 14.8, Polyglyceryl-6 Caprylate of HLB approx. 15 (as Dermofeel ®< G 6 CY from Dr. Straetmans GmbH / Evonik), Polyglyceryl-10 Laurate HLB approx. 16 (as Dermofeel ®< G 10 L from Dr. Straetmans GmbH / Evonik).

[0036] The O / W emulsifier of natural origin as described in the present application is preferably chosen from alkyl polyglucosides, sometimes also called alkyl polyglycosides, and designated by the acronym APG. These emulsifiers are non-ionic surfactants well known per se. Patent FR 2 948 285 presents them in terms of structure, and explains how to prepare them. They can be represented by the following general formula (I): R 1 -O-(R 2 -O) p -(S) n

[0037] In which: S represents a reducing saccharide, which may comprise between 5 and 6 carbon atoms, R1 denotes a linear or branched alkyl and / or alkenyl radical comprising approximately 8 to 24 carbon atoms, or an alkylphenyl radical whose linear or branched alkyl group comprises approximately 8 to 24 carbon atoms, R2 denotes an alkylene radical comprising 2 to 4 carbon atoms, n denotes a value ranging from 1 to 15, p denotes a value ranging from 0 to 10.

[0038] By reducing saccharide, in formula (I), we mean the saccharide derivatives which do not have in their structures a glycosidic bond established between an anomeric carbon and the oxygen of an acetal group as defined in the reference work: "Biochemistry", Daniel Voet / Judith G. Voet, p. 250, John Wyley & Sons, 1990. The oligomeric structure (S) n , can be present in any form of isomerism, whether optical isomerism, geometric isomerism or positional isomerism; it can also represent a mixture of isomers.

[0039] According to a particular aspect described in the present application, in the definition of the compounds of formula (I), S represents a reducing saccharide chosen from glucose, dextrose, sucrose, fructose, idose, gulose, galactose, maltose, isomaltose, maltotriose, lactose, cellobiose, mannose, ribose, xylose, arabinose, lyxose, allose, altrose, dextran or tallose and more particularly a reducing saccharide chosen from glucose, xylose or arabinose.

[0040] A first preferred variant of alkyl polyglucosides described in the present application are C12-C20 alkyl glucosides, i.e. compounds of formula (I) in which: R1 more particularly denotes a linear or branched alkyl and / or alkenyl radical comprising approximately 12 to 20 carbon atoms p takes a value ranging from 0 to 3, and preferably equal to zero, S denotes glucose, fructose or galactose, and more preferably glucose

[0041] A second preferred variant of alkyl polyglucosides described in the present application are the C12-C20 alkyl glucosides of the first preferred variant in which: R1 more particularly denotes a linear alkyl radical comprising approximately 12 to 20 carbon atoms p is equal to zero, S denotes glucose

[0042] Alkyl polyglucosides of formula (I) are commercially available under the names: Plantacare ®< 810 UP (R 1 is C8-C10 / INCI: caprylyl / capryl glucoside), Plantacare ®< 818 UP (R 1 is C8-C16 / INCI: Coco-glucoside), Plantacare ®< 2000 UP (R 1 is C8-C16 / INCI: decyl glucoside) and Plantacare ®< 1200 UP (R 1 is C12-C16 / INCI: lauryl glucoside) sold by BASF; Macanol ®< 810 (R 1 is C8-C10), Macanol ®< 1200 (R 1 is C12-C14), Macanol ®< 816 (mixture of R 1 is C8, C10, C12, C14, C16) sold by FCI Technology; Neocare MF 0718 (R 1 is C8-C10 / INCI: caprylyl / capryl glucoside), Neocare MF 0012 (R 1 is C12-C14 / INCI: lauryl glucoside), Neocare MF 0002 (R 1 is C8-C16 / INCI: decyl glucoside), Neocare MF 818 (R 1 is C8-C16 / INCI: coco glucoside) sold by Neochem; Tego Care CG 90 (R 1 is C14-C16 / INCI: cetearyl glucoside) sold by the company Evonik Healthcare.

[0043] The O / W emulsifier of natural origin may be a mixture consisting of at least one alkyl polyglucoside and at least one fatty alcohol. In these mixtures, the alkyl polyglucosides may be chosen from all the alkyl polyglucosides useful in the present description described previously. Concerning the fatty alcohols useful for mixing with the alkyl glucosides, linear or branched fatty alcohols having a total number of carbon atoms ranging from 8 to 24 will be found.

[0044] Mixtures of alkyl polyglucosides and fatty alcohols useful according to the present description and commercially available are those sold by the company SEPPIC: Montanov ™< 14 (INCI: Myristyl Alcohol & Myristyl Glucoside), Montanov ™< 202 (INCI: Arachidyl Alcohol and Behenyl Alcohol and Arachidyl Glucoside), Montanov ™< 68 (INCI: Cetearyl Alcohol & Cetearyl Glucoside), Montanov ™< 82 (INCI: Cetearyl Alcohol and Coco-Glucoside), Montanov ™< S (INCI: Coco-Glucoside & Coconut Alcohol), Montanov ™< L (INCI: C14-22 Alcohols & C12-20 Alkyl Glucoside).

[0045] The preferred mixture of alkyl polyglucoside and fatty alcohol is that marketed by SEPPIC under the name “Montanov ™< L”, which is a mixture of C14-C22 fatty alcohols and C12-C20 alkyl polyglucosides (INCI: C14-22 Alcohols & C12-20 Alkyl Glucoside). The more preferred mixture of alkyl polyglucoside and fatty alcohol is that marketed by SEPPIC under the name “Montanov ™< 68” (INCI: Cetearyl Alcohol & Cetearyl Glucoside).

[0046] The O / W emulsifier of natural origin according to the present description may also be chosen from fatty esters of dextrins or hydrolyzed starches, in particular in the form of sodium octenylsuccinate esters. These may be, for example, the products marketed by the Applicant under the names CLEARGUM ®< and in particular the products CLEARGUM ®< CO 01 and CLEARGUM ®< CO 03.

[0047] The emulsifying composition according to the present description makes it possible to obtain interesting sensory effects, such as a particular texture or a sensation of freshness, depending on the proportions used.

[0048] The interesting properties of the said emulsifying composition result from the combination of the two compounds used which present a good synergy both in terms of stability of the emulsions and sensory properties. Although very satisfactory results are obtained whatever the proportions in which these compounds are combined, particularly convincing results are obtained when they are combined in a very precise ratio.

[0049] In particular, each of the different constituents of the present emulsifying composition according to the present description can be integrated into a different phase, before the emulsification is carried out. Alternatively, the different compounds of the present composition according to the present description are mixed together to constitute what will be referred to hereinafter as the “emulsifying system”, said emulsifying system being able to be added to one or the other of the two immiscible phases to allow the formation of an O / W emulsion. The present description advantageously allows these two embodiments with the same compounds, which allows increased room for maneuver and simplified use.

[0050] Such an emulsifying composition according to the present description has in particular the advantage of being completely of natural origin, and of being usable according to a cold process and in particular at room temperature. Said composition according to the present description is for cosmetic use and, as such, is not sensitive to reasonable variations in pH or salinity of the medium, is not irritating and is not likely to cause allergies, in particular skin allergies. In addition, the composition according to the present description can be used to produce any type of emulsion, in particular Pickering-type emulsions, and is therefore suitable for a wide variety of uses: creams, milks, serums, lotions, etc.

[0051] The emulsifying composition according to the present description makes it possible to produce Pickering-type emulsions which can advantageously be stabilized by organic particles compatible with the skin or hair. It may additionally comprise other products capable of forming or stabilizing Pickering emulsions such as silicas and octenylsuccinate granular starches in the form of calcium or aluminum salts.

[0052] Preferably, the emulsifying composition also comprises at least one polyol.

[0053] The polyols covered by the present Application are all polyols known elsewhere, and in particular maltitol, mannitol, xylitol, erythritol, sorbitol, glycerol, glycerol and sorbitol being the preferred polyols. Preferably, this polyol is crystallized or is in the form of a powder.

[0054] According to the present description, the emulsifying composition, in particular for cosmetic use and capable of allowing the production of an oil-in-water (O / W) type emulsion, contains, in % by weight: 1) from 40% to 95% of at least one cyclodextrin, 2) from 5% to 40% of at least one O / W emulsifier of natural origin, preferably chosen from alkyl polyglucosides, mixtures of at least one alkyl polyglucoside and at least one fatty alcohol, and non-ethoxylated fatty esters of polyols, having a Hydrophilic-Lipophilic balance (HLB) greater than 8, preferably greater than or equal to 9, 3) and from 0% to 40% of at least one polyol.

[0055] Preferably, this emulsifying composition according to the present description is characterized in that it contains, in % by weight: 1) from 45% to 85% of at least one cyclodextrin, 2) from 5% to 30% of at least one O / W emulsifier of natural origin, preferably chosen from alkyl polyglucosides, mixtures of at least one alkyl polyglucoside and at least one fatty alcohol, and non-ethoxylated fatty esters of polyols, having a Hydrophilic-Lipophilic balance (HLB) greater than 8, preferably greater than or equal to 9, 3) and from 10% to 40% of at least one polyol.

[0056] Most preferably, this composition according to the present description is characterized in that it contains, in % by weight: 1) from 40% to 80% of at least one cyclodextrin, 2) from 10% to 20% of at least one O / W emulsifier of natural origin, preferably chosen from alkyl polyglucosides, mixtures of at least one alkyl polyglucoside and at least one fatty alcohol, and non-ethoxylated fatty esters of polyols, having a Hydrophilic-Lipophilic balance (HLB) greater than 8, preferably greater than or equal to 9, 3) and from 10% to 30% of at least one polyol.

[0057] Preferably, the H / W emulsifier of natural origin having a Hydrophilic-Lipophilic balance (HLB) greater than 8 is a product that is naturally biodegradable in a hydrated natural environment, and most preferably a mixture of at least one alkyl polyglucoside and at least one fatty alcohol.

[0058] Another subject of the present invention relates to a composition of the Pickering H / W emulsion type, in particular for cosmetic use, characterized in that it contains for 1 part by weight of at least one cyclodextrin, between 0.01 and 1 part, preferably between 0.15 and 0.30 part of a mixture of at least one C12-C20 alkyl polyglucoside and at least one linear or branched fatty alcohol having a total number of carbon atoms ranging from 8 to 24, said mixture having a Hydrophilic-Lipophilic balance (HLB) greater than 8, preferably greater than or equal to 9.

[0059] Also described is a composition of the Pickering H / W emulsion type, in particular for cosmetic use, characterized in that it contains for 1 part by weight of at least one cyclodextrin, between 0.01 and 1 part, preferably between 0.05 and 0.5 part, more preferably between 0.10 and 0.35 part, and better still between 0.15 and 0.30 part of at least one H / W emulsifier of natural origin, the latter preferably chosen from alkyl polyglucosides, mixtures of at least one alkyl polyglucoside and at least one fatty alcohol, and non-ethoxylated fatty esters of polyols, having a Hydrophilic-Lipophilic balance (HLB) greater than 8, preferably greater than or equal to 9.

[0060] The Pickering H / W emulsion type composition according to the present description may further comprise a fatty phase which may be at room temperature (25°C), liquid such as vegetable oils, or solid as in the case of waxes. This liquid fatty phase may be of mineral, animal, vegetable or synthetic origin and may be composed of hydrocarbon oils or possibly silicone oils. By hydrocarbon oil is meant an oil formed essentially, or even consisting of, carbon and hydrogen atoms and possibly oxygen or nitrogen atoms, which may contain alcohol, ester, ether, carboxylic acid, amine and / or amide groups.

[0061] Preferably, this composition contains one or more oils that are liquid at room temperature (25°C), preferably at least one non-volatile liquid oil. Non-volatile liquid oil means an oil that can remain on the skin at room temperature, at atmospheric pressure for at least one hour.

[0062] The liquid fatty phase advantageously comprises one or more non-volatile oils which provide an emollient effect on the skin. Fatty esters such as cetearyl isononoate, isotridecyl isononoate, isostearyl isostearate, isopropyl isostearate, isopropyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, isononyl isononate, 2-ethylhexyl palmitate, 2-hexyldecyl laurate, 2-octyl decyl palmitate, 2-octyldodecyl myristate or lactate, 2-diethylhexyl succinate, diisostearyl malate, tracetin, tricprin, caprylic / capric acid triglycerides, glycerin triisostearate, tocopherol acetate, higher fatty acids such as myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, linoleic acid, linolenic acid or isostearic acid, higher fatty alcohols such as oleic alcohol,vegetable oils such as avocado oil, camellia oil, hazelnut oil, tsubaki oil, cashew nut oil, argan oil, soybean oil, grape seed oil, sesame oil, corn oil, wheat germ oil, rapeseed oil, sunflower oil, cottonseed oil, jojoba oil, peanut oil, olive oil and their mixtures, vegetable butters such as shea butter, camellia butter.,

[0063] These oils can be hydrocarbon or silicone type oils such as paraffin oil, squalane, petrolatum, dimethyl siloxanes and their mixtures.

[0064] The liquid fatty phase may also optionally include volatile oils. A volatile oil is an oil that can evaporate from the skin in less than an hour at room temperature and atmospheric pressure. Volatile oils may be chosen, for example, from silicone oils or short fatty acid triglycerides to reduce the greasy feel.

[0065] Preferably, the Pickering H / W emulsion type composition according to the present description contains only oils of renewable origin and in particular oils or butters of vegetable origin, preferably refined. These oils and butters are perfectly suited to the emulsifying system which is the subject of the present description in the sense that they make it possible to obtain very stable emulsions, with high whiteness and easily adjustable viscosity.

[0066] The emulsifying composition according to the present description advantageously makes it possible to prepare O / W emulsions with very high oil contents. This type of oil-rich O / W emulsion is usually difficult to obtain in a stable form over time with conventional emulsifiers. The oil content of the final O / W emulsion is preferably between 10 and 65% by weight, and preferably of the order of 20 to 55% by weight. Vegetable oils or oils of vegetable origin such as sunflower oil and isopropyl palmitate make it possible in particular to obtain stable emulsions, which do not give rise to creaming or phase separation.

[0067] The composition according to the present description may further comprise a rheology agent such as in particular a thickening agent for the aqueous phase, a gelling agent or a suspending agent, such as for example gums derived from plants such as gum arabic, konjac gum, guar gum or their derivatives; gums extracted from algae such as alginates or carrageenans; gums derived from microbial fermentation such as xanthans, mannans, scleroglucans or their derivatives; cellulose and its derivatives such as carboxymethylcellulose or hydroxyethylcellulose; starch and its derivatives such as in particular modified starches, in particular acetylated, carboxymethylated, octenylsuccinate or hydroxypropylated; synthetic polymers such as polyacrylic acids or carbomers.

[0068] Preferably, the composition according to the present description comprises a rheology agent chosen from natural polysaccharides derived from plants or fermentation, optionally modified. Xanthan and its derivatives make it possible in particular to obtain O / W emulsions with very fine droplet sizes, even when used at a content of less than 1% by weight of the total emulsion.

[0069] The emulsions obtained by using the emulsifying composition according to the present description preferably have a drop size less than or equal to 30 µm, preferably less than or equal to 10 µm. By drop size of the emulsion is meant the average diameter of the drops of dispersed fatty phase suspended in the aqueous phase. A small drop size increases the stability of the emulsion by reducing the flocculation rate of the emulsion, and therefore the rate of phase separation. The drop size depends on a large number of parameters and, as such, constitutes a characteristic which should be controlled and which is not intrinsic to the formulation of the emulsifying system. The size of the droplets is measured using a LEICA DMLS optical microscope at x10 magnification.

[0070] The composition according to the present description may further comprise a preservative chosen from benzyl alcohol, dehydroacetic acid and mixtures thereof.

[0071] The composition according to the present description preferably has a Brookfield viscosity greater than 3,000 mPas at 25°C, preferably greater than 5,000 mPas at 25°C. The viscosity is measured using a Brookfield DV-II+Pro viscometer rotated at a speed of 20 rotations per minute in contact with the produced sample. The resistance of the product to this rotational movement is recorded for one minute and converted into mPascal.second. For each sample, the viscosity is measured three times and the arithmetic mean of the three values ​​is retained. A spindle adapted to the measured viscosity is selected according to the following ranges: the spindle chosen is spindle SP3 when the viscosity is less than or equal to 5,000 mPa.s, SP4 when the viscosity is between 5,000 mPa.s and 7,000 mPa.s and SP5 when the viscosity is greater than or equal to 7,000 mPa.s.

[0072] In order to characterize the sensory properties of the emulsifying systems according to the present description, sensory descriptors and a corresponding 5-step sensory evaluation protocol are used. These 5 steps correspond to the different application phases of a care product: appearance, handling, spreading after 1 minute, after 2 minutes. During these 5 phases, several sensory descriptors are evaluated by a panel of evaluators who assign a score ranging from 0 to 10.

[0073] The composition according to the present description preferably has a whiteness descriptor greater than 8. The whiteness descriptor is defined by the color palette of the figure 1 The product is examined under the lamp and compared to the color palette by a panel of evaluators.

[0074] The composition according to the present description preferably has a gloss descriptor greater than or equal to 8. Gloss is defined by the propensity of the product to reflect light.

[0075] The composition according to the present description preferably has a spreading descriptor greater than 8. The spreading is evaluated by examining the product after depositing 50 to 100µl of the product on the hand, during its spreading in 10 rotations, under a lamp. The spreading is all the greater as there is little resistance to movement between the 5th and 10th rotation on the hand.

[0076] The composition according to the present description preferably has a film-forming descriptor greater than 8. The film-forming descriptor corresponds to the propensity of the product to form a continuous film by sliding on the skin 2 minutes after having carried out 10 rotations.

[0077] Another subject of the present invention consists of a method for manufacturing a composition of the H / W Pickering emulsion type, in particular for cosmetic use, comprising the following steps: a) the dispersion in an aqueous phase of an emulsifying composition comprising at least one cyclodextrin and a mixture of at least one C12-C20 alkyl polyglucoside and at least one linear or branched fatty alcohol having a total number of carbon atoms ranging from 8 to 24, the latter being present in a ratio of between 0.01 and 1 part, preferably between 0.15 and 0.30 part, per 1 part by weight of at least this cyclodextrin;this mixture of at least one C12-C20 alkyl polyglucoside and at least one linear or branched fatty alcohol having a total number of carbon atoms ranging from 8 to 24 having a Hydrophilic-Lipophilic balance (HLB) greater than 8, preferably greater than or equal to 9, b) adding to the mixture obtained in step a) a fatty phase, in an amount of between 10 and 65% by weight with sufficient mechanical stirring to allow the dispersion of the fatty phase in fine droplets in the aqueous phase and the obtaining of an H / W emulsion having a drop size less than or equal to 30 µm, preferably less than or equal to 10 µm. ;

[0078] Also described is a method for manufacturing a Pickering H / W emulsion type composition, in particular for cosmetic use, comprising the following steps: a) the dispersion in an aqueous phase of an emulsifying composition comprising at least one cyclodextrin and at least one O / W emulsifier of natural origin, the latter being present in a ratio of between 0.01 and 1 part, preferably between 0.05 and 0.5 part, more preferably between 0.10 and 0.35 part, and better still between 0.15 and 0.30 part, per 1 part by weight of at least this cyclodextrin;this H / W emulsifier of natural origin may be chosen in particular from at least one alkyl polyglucoside, at least one mixture of at least one alkyl polyglucoside and at least one fatty alcohol, and at least one non-ethoxylated fatty ester of polyols, more preferably chosen from mixtures of at least one alkyl polyglucoside and at least one fatty alcohol, having a Hydrophilic-Lipophilic balance (HLB) of less than 8, preferably greater than or equal to 9, b) adding to the mixture obtained in step a) a fatty phase, preferably in an amount of between 10 and 65% by weight, and preferably of the order of 20 to 55% by weight relative to the final weight of the emulsion, with sufficient mechanical stirring to allow the dispersion of the fatty phase in fine droplets in the aqueous phase and the obtaining of an H / W emulsion having a drop size of less than or equal to 30 µm, preferably less than or equal to 10 µm.;

[0079] According to a variant, the method according to the present description for manufacturing a composition of the H / W Pickering emulsion type, in particular for cosmetic use, comprising the following steps: a) the dispersion in a fatty phase of an emulsifying composition comprising at least one cyclodextrin and at least one O / W emulsifier of natural origin, the latter being present in a ratio of between 0.01 and 1 part, preferably between 0.05 and 0.5 part, more preferably between 0.10 and 0.35 part and better still between 0.15 and 0.30 part per 1 part by weight of at least this cyclodextrin; this H / W emulsifier of natural origin can be chosen in particular from at least one alkyl polyglucoside, a mixture of at least one alkyl polyglucoside and at least one fatty alcohol, and a non-ethoxylated fatty ester of polyols, more preferably chosen from mixtures of at least one alkyl polyglucoside and at least one fatty alcohol, having a Hydrophilic-Lipophilic balance (HLB) greater than 8, preferably greater than or equal to 9;the fatty phase preferably representing between 10 and 65% by weight, and preferably of the order of 20 to 55% by weight of the final weight of the emulsion, b) and the addition of the mixture obtained in step a) to an aqueous phase_under sufficient mechanical stirring to allow the dispersion of the fatty phase in fine droplets in the aqueous phase and the obtaining of an H / W emulsion having a drop size less than or equal to 30 µm, preferably less than or equal to 10 µm.;

[0080] The invention may be better understood using the non-limiting exemplary embodiments described below. EXAMPLE 1

[0081] The invention may be better understood with the aid of the non-limiting exemplary embodiments described below, and by examining the appended figures: there figure 1 represents the color palette used for the evaluation of the whiteness descriptor; the figure 2is a photograph of 6 O / W emulsions obtained from emulsifying compositions according to the invention.

[0082] Six compositions in the form of an O / W emulsion according to the invention were produced using the following protocol. The compositions of these six compositions are shown in Table 1.

[0083] A gelling agent is first dispersed in water while stirring with a deflocculation paddle at 1000 rpm. The water temperature is set at 40°C when the gelling agent is xanthan gum, and at 70°C when the gelling agent is hydroxyethylcellulose.

[0084] The beta-cyclodextrin is then moistened in glycerin and the beta-cyclodextrin / glycerin mixture is added to the water / gelling agent mixture while stirring at 1000 rpm, in order to obtain an aqueous phase.

[0085] The quantity of beta cyclodextrins is set at 2% or 5% by mass of the composition depending on the case.

[0086] Separately, the alkyl polyglucoside MONTANOV 68 (INCI: cetearyl alcohol & cetearyl glucose), from the company SEPPIC, is added to sunflower oil or isopropyl palmitate under magnetic stirring, at 40°C to obtain an oily phase.

[0087] The oily phase is then emulsified in the aqueous phase at 40°C with stirring at 1500 revolutions per minute, for 15 minutes.

[0088] A preservative is added (a mixture of benzyl alcohol and dehydroacetic acid). Table 1 % Beta-cyclodextrin Oil (30%) Emulsifier (1%) Thickener (0.7%) 1 5 Sunflower Montanov ™< 68 Hydroxyethyl Cellulose 2 5 Sunflower Montanov ™< 68 Hydroxyethyl Cellulose 3 2 Isopropyl Palmitate (IPP) Montanov ™< 68 Hydroxyethyl Cellulose 4 2 Sunflower Montanov ™< 68 Xanthan 5 2 Isopropyl Palmitate (IPP) Montanov ™< 68 Xanthan 6 5 Isopropyl Palmitate (IPP) Montanov ™< 68 Xanthan

[0089] There figure 2 is a photograph of the 6 O / W emulsions obtained according to the formulations given in table 1.

[0090] It is noted that all the emulsions according to the invention comprising 1% of Montanov ™ < 68 (cetearyl alcohol and cetearyl glucose) and 2 or 5% of beta-cyclodextrin make it possible to obtain stable O / W emulsions using only 1%m of usual O / W emulsifier.

[0091] For each of these compositions, viscosity, drop size, whiteness, spreadability, greasyness, and penetrating character are measured. The compositions may be referred to interchangeably by the terms samples Or product in the remainder of this detailed description.

[0092] Viscosity is measured using a Brookfield DV-II+Pro viscometer. A fixed-size spindle (SP2 to SP7 spindles used according to the viscosity levels in accordance with the device's instructions) is rotated at a speed of 20 revolutions per minute in contact with the produced sample. The product's resistance to this rotational movement is recorded for one minute and converted into milliPascal.second, noted mPa.s. For each sample, the viscosity is measured three times and the arithmetic mean of the three values ​​is taken.

[0093] The whiteness descriptor is defined by the color palette of the figure 1 The product is examined under the lamp and compared to the color palette by a panel of evaluators.

[0094] Spreading is assessed by examining the product after depositing 50 to 100µl of the product on the hand, while spreading it in 10 rotations, under a lamp. Spreading is all the greater when there is little resistance to movement between the 5th and 10th rotation on the hand.

[0095] The oiliness of the compositions is assessed by examining the product under the lamp, 1 minute after rotating the product 10 times on the skin. A panel of evaluators then evaluates the resistance of the product when the skin on which it has been applied is placed between the thumb and index finger and a rubbing movement is applied. The panel of evaluators also takes into account the oiliness or lack thereof given to the skin.

[0096] Finally, the penetrating nature of the product is assessed by examining the product under the lamp two minutes after rotating the product 10 times on the skin, sliding it across the skin. A panel of assessors then evaluates the amount of product residue recovered.

[0097] The results obtained for the 6 O / W emulsion type compositions are recorded in Table 2. Table 2 Viscosity in mPa.s (pin used) Droplet size (microns) White Spreading Fat Penetrating 1 12 120 (SP5) Less than 10 10 7 7 10 2 12 233 (SP5) Less than 10 10 7 7 10 3 4,417 (SP3) Less than 10 10 8 5 10 4 4,917 (SP3) From 10 to 30 9 10 7 8 5 3,940 (SP3) From 10 to 20 10 10 6 10 6 4,517 (SP3) From 10 to 30 9 10 9 7

[0098] The viscosity of the emulsions increases slightly when the beta-cyclodextrin concentration increases: it goes from 3,900 - 4,900 mPa.s with 2% beta-cyclodextrin to more than 12,000 mPa.s with 5%. Similarly, the viscosity is higher when the thickener used is cellulose instead of xanthan: it goes from 4,500 to 12,000 mPa.s. The emulsifying compositions according to the invention advantageously make it possible to obtain a very wide range of viscosity, which can be used to prepare both milks and viscous creams.

[0099] It can be noted that all the H / W emulsions obtained using the emulsifying compositions according to the invention have excellent sensory properties (scores ranging from 6 to 10 according to the white, spreading, fat and penetrating criteria).

[0100] Emulsions are less white when the oil used is sunflower oil than when the oil used is isopropyl palmitate (noted IPP): the descriptor is 10 out of 10 in the case of sunflower oil, compared to 9.33 out of 10 on average in the case of isopropyl palmitate. However, the whiteness of isopropyl palmitate remains satisfactory.

[0101] Spreading is significantly easier with xanthan than with cellulose, increasing from 7.33 with cellulose to 10 with xanthan.

Claims

1. An emulsifying composition, in particular for cosmetic use, allowing an oil-in-water (O / W) emulsion to be obtained, the emulsion comprising: a. at least one cyclodextrin, and b. and at least one O / W emulsifier, wherein the O / W emulsifier is a mixture of at least one C12-C20 alkyl polyglucoside and at least one linear or branched fatty alcohol having a total carbon atom number ranging from 8 to 24, the O / W emulsifier having a hydrophilic-lipophilic balance (HLB) greater than 8, preferentially greater than or equal to 9.

2. The emulsifying composition as claimed in claim 1, characterized in that the O / W emulsifier is present in the emulsifying composition in a ratio of between 0.01 and 1 part, preferably between 0.05 and 0.5 part, more preferentially between 0.10 and 0.35 part, and even better still between 0.15 and 0.30 part, per 1 part by weight of cyclodextrin.

3. The emulsifying composition as claimed in claim 1 or 2, wherein said at least one cyclodextrin is selected from alpha-, beta-, and gamma-cyclodextrins, preferably from native beta-cyclodextrin.

4. The emulsifying composition as claimed in any one of the preceding claims, wherein the cyclodextrin is present in the form of a crystalline, pseudo-crystalline or amorphous powder.

5. The emulsifying composition as claimed in any one of the preceding claims, wherein the O / W emulsifier is also selected from products which are naturally biodegradable in a hydrated natural medium with a hydrophilic-lipophilic balance (HLB) of between 8 and 20, preferably between 9 and 16 and even better still between 11 and 14.

6. The emulsifying composition as claimed in any one of the preceding claims, wherein the O / W emulsifier is a mixture consisting of C14-C22 fatty alcohol and of C12-C20 alkyl polyglucoside.

7. The emulsifying composition as claimed in any of claims 1 to 6, also comprising at least one polyol, which is preferably selected from maltitol, mannitol, xylitol, erythritol, sorbitol and glycerol.

8. The emulsifying composition as claimed in any of claims 1 to 7, wherein the composition contains, in % by weight: a. 40% to 95% of at least one cyclodextrin, b. 5% to 40% of a mixture of at least one C12-C20 alkyl polyglucoside and at least one linear or branched fatty alcohol having a total number of carbon atoms ranging from 8 to 24, having a hydrophilic-lipophilic balance (HLB) greater than 8, preferentially greater than or equal to 9, and c. and 0% to 40% of at least one polyol.

9. A composition of the O / W Pickering emulsion type, in particular for cosmetic use, characterized in that it contains, per 1 part by weight of at least one cyclodextrin, between 0.01 and 1 part, preferably between 0.15 and 0.30 part of a mixture of at least one C12-C20 alkyl polyglucoside and at least one linear or branched fatty alcohol having a total number of carbon atoms ranging from 8 to 24, said mixture having a hydrophilic-lipophilic balance (HLB) greater than 8, preferentially greater than or equal to 9.

10. The composition as claimed in claim 9, containing one or more oils which are liquid at ambient temperature 25°C, preferably at least one nonvolatile liquid oil.

11. The composition as claimed in claim 10, wherein the oil content of the final O / W emulsion is between 10 and 65% by weight, and preferably between 20 and 55% by weight.

12. The composition as claimed in any of claims 9 to 11, further comprising a rheological agent, preferably a thickener for the aqueous phase, a gelling agent or a suspension agent.

13. The composition as claimed in any of claims 9 to 12, having a droplet size of less than or equal to 30 µm, preferentially less than or equal to 10 µm, the droplet size being measured by the method disclosed in the description.

14. The composition as claimed in any of claims 9 to 13, having a Brookfield viscosity of greater than 3000 mPas at 25°C and 20 rpm, preferably greater than 5000 mPas at 25°C and 20 rpm.

15. A process for producing a composition of the O / W Pickering emulsion type, in particular for cosmetic use, comprising the following steps: a) the dispersion in an aqueous phase of an emulsifying composition comprising at least one cyclodextrin and a mixture of at least one C12-C20 alkyl polyglucoside and at least one linear or branched fatty alcohol having a total number of carbon atoms ranging from 8 to 24, the latter being present in a ratio of between 0.01 and 1 part, preferably between 0.15 and 0.30 part, per 1 part by weight of at least this cyclodextrin; this mixture of at least one C12-C20 alkyl polyglucoside and at least one linear or branched fatty alcohol having a total number of carbon atoms ranging from 8 to 24 having a hydrophilic-lipophilic balance (HLB) greater than 8, preferentially greater than or equal to 9, b) the addition, to the mixture obtained in step a), of a fatty phase, in an amount of between 10 and 65% by weight, with mechanical stirring sufficient to allow the fatty phase to be dispersed as fine droplets in the aqueous phase and for an O / W emulsion which has a droplet size of less than or equal to 30 µm, preferentially less than or equal to 10 µm, the droplet size being measured by the method disclosed in the description.