Oil-in-water emulsion comprising an emulsifier system consisting of a cyclodextrin and an emulsifier of starch origin

Abstract

The present application relates to an oil-in-water emulsion obtained by means of an emulsifier system which is of natural origin and consists of a cyclodextrin and a starch-based emulsifier and / or an emulsifier of starch origin, preferably a native beta-cyclodextrin and an octenyl succinate-modified pregelatinized hydrolysed starch. The emulsion has the advantage of having a viscosity which can be adjusted in a range from 3000 mPa.s to less than 10 mPa.s, making it possible to obtain various forms ranging from gel, through milk, to fluid lotion. These emulsions are suitable as cosmetic, dermatological, veterinary and pharmaceutical products. In particular in cosmetics, these emulsions can be used in skincare, in haircare, in oral care, in hygiene and in make-up.

Description

Description Title: Oil-in-water emulsion comprising an emulsifying system consisting of a cyclodextrin and an emulsifier of starchy origin Technical field

[0001] The invention relates to the field of oil-in-water emulsions, in particular cosmetic or dermatological emulsions in which the emulsifying surfactants are mainly of natural origin, and which may even be entirely of natural origin. Prior art

[0002] Concerning the emulsifying properties of cyclodextrins and emulsifiers of starchy origin separately, the state of the art teaches that cyclodextrins are emulsifiers capable of forming Pickering oil-in-water emulsions, which are emulsions stabilized by fine insoluble particles, and also that emulsifiers of starchy origin, for example octenyl succinate starches, are emulsifiers capable of forming oil-in-water, Pickering or conventional emulsions stabilized by amphiphilic molecules comprising a hydrophobic part and a hydrophilic part.

[0003] Conventional emulsions are stabilized by surfactant and amphiphilic molecules comprising a hydrophobic part and a hydrophilic part which are placed at the interfaces between water and oil and lower the interfacial tensions. The so-called Pickering emulsions are stabilized without the use of surfactant, by very fine particles (and not molecules) of silica, talc or granular starches..., at the same time insoluble, solid, colloidal and without effect on the interfacial tensions, adsorbing irreversibly at the interfaces of the emulsion drops, thus giving them long-term stability.

[0004] Concerning the combination of a cyclodextrin and another emulsifier, Henkel patent application WO2008 / 003685 teaches combining the cyclodextrin with a hydrophobically modified polysaccharide, said polysaccharide preferably being a modified cellulose, particularly Hydroxypropylmethylcellulose. The hydrophobically modified polysaccharides presented are exclusively celluloses. The proposed emulsifying system is capable of forming stable oil-in-water emulsions, with low or no amounts of low molecular weight surfactants, in order to reduce or avoid irritation, dehydration and redness of the skin. This application proposes to add modified starches in addition to the cyclodextrin and the hydrophobically modified polysaccharide, but does not specify any nature of the modification of said starches.

[0005] Wuhan Polytechnic University patent CN 112759772 proposes a method for preparing a Pickering emulsion including a step of preparing a starch octenyl succinate from a millet starch in a granular state, followed by a step of adding beta-cyclodextrin to a starch milk prepared with said millet starch octenylsuccinate, and finally the addition of a medium chain length triglyceride. This patent specifies that the cyclodextrin content in the aqueous phase would preferably be 1 to 3% by weight of the aqueous phase, and remains silent on the choice of the millet starch octenyl succinate content, whether in the aqueous phase or the fatty phase. In this patent, the starch octenyl succinate is said to be prepared in the form of a starch milk, meaning for those skilled in the art that the starch is dispersed and not solubilized in water.The ability of this millet starch to form Pickering emulsions is, as known in the literature, essentially due to the combination of octenyl succinate modification and the very small size of the starch particles. Such a mechanism is for example described by Li et al in their article “Starch granules as Pickering emulsifiers: role of octenylsuccinylation and particle size” in the journal Food Chemistry, 2019, vol. 283, p.437-444. In addition, the viscosities of the emulsions disclosed in this patent CN 112759772 are very high: at least 10,000 mPa.s for a shear of 0.1 s. -1 These viscosity values ​​are incompatible with obtaining thin to fluid, or even very fluid, emulsions according to the present invention.

[0006] Beiersdorf's patent application EP1923044 discloses cosmetic emulsions comprising three compounds: a cellulose ether, a water-soluble carbohydrate, and a water-insoluble modified starch. Cyclodextrin is among the possible water-soluble carbohydrates, but is not the preferred one and is not exemplified. Maltodextrins are preferred. Starch octenyl succinate is among the possible modified starches, and the preferred modified starch is the aluminum salt of starch octenylsuccinate. All emulsions proposed and disclosed by this application comprise all three compounds together. Technical problem

[0007] Oil-in-water emulsions widely used in cosmetics and dermatology are obtained by mixing an oily phase and an aqueous phase in the presence of one or more emulsifying surfactants. Historically, since the advent of petrochemicals, these emulsifying surfactants were molecules obtained by chemical synthesis from raw materials exclusively derived from petrochemicals. Despite their good performance in emulsifying and stabilizing various emulsions, the discovery of the harmfulness of some of them in the medium or long term, as well as the pollution linked to their production and their release into the environment, are pushing the cosmetics market towards emulsions containing little or no of these emulsifying surfactants of petrochemical origin.

[0008] Natural emulsifying surfactants have been known for several years now and are used in cosmetic emulsions as a partial or total replacement for petrochemical emulsifying surfactants. However, the physical qualities of emulsions obtained with said natural emulsifying surfactants are difficult to match those of emulsions obtained with petrochemical emulsifying surfactants. Among the desired qualities, viscosity, stability of the emulsion during storage, and sensory profile are the three most important. The target values ​​for these qualities may vary depending on the target market, both in terms of application and country, and according to consumer preferences.For example, gel-like emulsions may be preferred for some products, such as moisturizers, while thick or fluid milk-like emulsions may be preferred for other products, such as sunscreen or after-sun care products. Gels generally have. viscosities of several thousand mPa.s, while thick milks have viscosities of less than 1000 mPa.s, or even 500 mPa.s, and even rather close to 100 mPa.s, and fluid milks have viscosities of a few tens of mPa.s.

[0009] Having emulsions obtained from emulsifying surfactants of natural origin whose viscosities can be adjusted to prepare products meeting these preferences is thus a need of cosmetic product producers. It would also be an economic and also ecological advantage if this need could be satisfied by using the same emulsifying surfactant, or at the very least, by using a mixture of molecules and / or macromolecules of natural origin, to obtain different viscosities. This is the main subject of the present application: an oil-in-water emulsion comprising an emulsifying system composed of a cyclodextrin and an emulsifier of starchy origin. Summary of the purpose of this application

[0010] According to a first object, the invention relates to an oil-in-water (O / W) emulsion comprising: - an oily phase dispersed in an aqueous phase, - an emulsifying system consisting of at least one cyclodextrin and at least one starchy and / or starchy-origin emulsifier, said emulsion having a Brookfield viscosity, at 20°C at 20 rpm for 1 min with the SP5 spindle, of less than 3000 mPa.s, preferably less than or equal to 2800 mPa.s, preferably less than or equal to 2600 mPa.s, and in which the starchy and / or starchy-origin emulsifier has a solubility in water at 22°C according to test A of greater than or equal to 50%, or greater than or equal to 75%, or greater than or equal to 85%, or greater than or equal to 95%, or greater than or equal to 98%, or greater than or equal to 99%, or equal to 100%.

[0011] In embodiments, the O / W emulsion according to the invention further comprises the following characteristics: - said emulsion has a Brookfield viscosity at 20°C at 20 rpm for 1 min with the SP1 spindle, greater than 10 mPa.s, preferably greater than or equal to 20 mPa.s, preferably greater than or equal to 30 mPa.s, preferably greater than or equal to 50 mPa.s; - the emulsion is biodegradable at more than 90%, in particular at more than 93% according to the OECD 301 F standard; - the emulsion comprises less than 1% by weight, preferably less than 0.5% by weight, preferably 0% by weight, of surfactant having a molecular weight or mass average molecular weight, less than or equal to 250 Da, preferably less than or equal to 500 Da, preferably less than or equal to 750 Da, preferably less than or equal to 1 kDa, preferably less than or equal to 10 kDa; - said at least one cyclodextrin is chosen from native cyclodextrins and modified cyclodextrins, preferably from native or modified alpha-cyclodextrin, gamma-cyclodextrin or beta-cyclodextrin, more preferably from native alpha-cyclodextrin, gamma-cyclodextrin or beta-cyclodextrin, and most preferably is native beta-cyclodextrin; - the starchy or starchy emulsifier is a starch, a dextrin or a maltodextrin, in particular a starch; - the starchy and / or starchy emulsifier has a solubility in water at 22°C according to test A greater than or equal to greater than or equal to 50%, or greater than or equal to 75%, or greater than or equal to 85%, or greater than or equal to 95%, or greater than or equal to 98%; - said at least one starchy and / or starchy emulsifier comprises at least one amphiphilic group, preferably at least one alkenyl succinate group, preferably at least one alkali or alkaline earth metal octenyl succinate group, most preferably at least one sodium or calcium octenyl succinate group; - the starch is a pregelatinized, gelatinized, atomized, acid-hydrolyzed or enzymatically hydrolyzed starch, or a starch modified by a combination of these modifications, preferably the starch is a hydrolyzed and pregelatinized starch; - the starchy or starchy emulsifier is chosen from a granular starch octenyl succinate, a pregelatinized starch octenyl succinate, a gelatinized starch octenyl succinate, a hydrolyzed starch octenyl succinate, a hydrolyzed and pregelatinized starch octenyl succinate, a dextrin octenyl succinate, a maltodextrin octenyl succinate, and mixtures thereof; - the ratio of the mass of starchy emulsifier or emulsifier of starchy origin to the mass of cyclodextrin is within a range from 0.2 to 2, preferably from 0.3 to 1.6, preferably from 0.4 to 1.2, preferably from 0.5 to 1, preferably from 0.55 to 0.9, and most preferably from 0.60 to 0.80; - the mass content of said emulsifying system in said emulsion is greater than or equal to 0.5% by weight, preferably 1% by weight, preferably 1.5% by weight, preferably 2% by weight, preferably 2.5% by weight, preferably 3% by weight, preferably 3.5% by weight, preferably 4% by weight, preferably 4.5% by weight, preferably 5% by weight; - the mass content of said emulsifying system relative to the total weight of the emulsion is less than or equal to 18% by weight, 10% by weight, 9% by weight, 8% by weight, 7% by weight, 6.5% by weight, and most preferably 6% by weight; - the mass content of said at least one cyclodextrin relative to the total weight of the emulsion is within a range from 0.25% to 9%, from 0.5 to 8% by weight of said emulsion, from 1.5 to 7% by weight, from 2 to 7% by weight, from 2.5 to 6% by weight, from 3 to 5% by weight, and most preferably from 3.5 to 4.5% by weight; - the mass content of said at least one starchy emulsifier and / or emulsifier of starchy origin relative to the total weight of the emulsion is within a range from 0.25 to 9%, from 0.5 to 8% by weight, from 1 to 7% by weight, from 1.5 to 6% by weight, from 2 to 5% by weight, and most preferably from 2.5 to 4.5% by weight; - the mass content of the oily phase relative to the total weight of the emulsion is within a range from 5 to 50% by weight, from 15 to 45% by weight, from 20 to 40% by weight, from 25 to 35% by weight; - the oily phase consists of at least one oil chosen from oils of natural origin, in particular vegetable oils, and mineral oils, silicones, preferably the oily phase consists of at least one oil of natural origin, in particular vegetable oil; - the emulsion further comprises at least one rheology agent, preferably a hydrophilic and / or hydrophobic thickener, preferably a hydrophilic thickener.

[0012] According to a second aspect, the invention relates to a cosmetic, dermatological or pharmaceutical composition comprising an oil-in-water emulsion according to the invention. In embodiments, the cosmetic, dermatological or pharmaceutical composition further comprises one or more of the following features: - it is a skin care product, a hair care product, a mouth care product, a makeup product, or a hygiene product, preferably a skin care product, a hair care product, a mouth care product, a makeup product; - it is a skin care product chosen from moisturizers, sunscreens, after-sun care; - it is a hair care product chosen from moisturizing hair care, conditioners, smoothing care, coloring; - it is a mouth care product chosen from toothpastes and mouthwashes; - it is a makeup product chosen from foundations, mascaras, eye shadows, lipsticks; - it is a hygiene product chosen from washing creams.

[0013] The present invention has several advantages.

[0014] One of the advantages of the emulsion that is the subject of the present application is that it essentially comprises, or even consists solely of, ingredients 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 emulsion according to the present application comprises a reduced quantity, or even zero, of traditional emulsifiers of petrochemical origin, in particular glycol derivatives and ethoxylated and polyethoxylated derivatives, which we are currently seeking to replace for environmental reasons (poor biodegradability) and safety reasons (ethylene oxide is toxic and flammable).

[0015] The emulsion also has the advantage of being able to be prepared using a cold process, particularly at room temperature. The emulsion thus has the advantage of not being irritating and of being unlikely to cause allergies, particularly skin allergies. Furthermore, the emulsion can take the form of numerous cosmetic products: creams, milks, serums, lotions, etc.

[0016] The main advantage of the emulsion that is the subject of the present application is that it has an adjustable Brookfield viscosity, in a wide range from 10 mPa.s to 3000 mPa.s, thus offering a wide range of sensory properties of interest. Indeed, the O / W emulsions according to the present application can be sprayable or fluid. The emulsions thus have a good emollient effect on the skin as well as a good moisturizing effect on the upper layers of the epidermis.

[0017] According to one embodiment, the emulsion comprising a cyclodextrin and a modified starch has a Brookfield viscosity of less than 3000 mPa.s, preferably less than or equal to 2800 mPa.s, preferably less than or equal to 2600 mPa.s, which can even reach values ​​of less than 10 mPa.s, while being stable, in the absence of an aqueous phase thickening agent.

[0018] Another advantage of the emulsion is that it is suitable for broad-spectrum cosmetic or dermatological use, i.e. versatile from the point of view of the final products envisaged: from this point of view, the emulsion, depending on the application, can be a fluid gel, a lotion, a cream, a milk, etc. Furthermore, said emulsion is advantageously non-irritating and non-allergic to the skin.

[0019] Another advantage is that the emulsion can be prepared by a process characterized by very simple implementation, with minimal energy input, in particular by introducing all the ingredients into the same tank or reactor (formulation known as "one pot" in English). From the point of view of its implementation, the process is advantageously "a cold process", unlike many conventional solid or pasty emulsifiers such as waxes which require a rise in temperature for their implementation (ingredient requiring to be melted and usable "hot") above 60°C, or even 80°C. The concept of cold process includes emulsification processes in which the only heat input is that due to the dissipation of energy caused by mechanical agitation. By "cold process" we mean that the emulsion can be prepared at temperatures less than or equal to 45°C, or 35°C, or better still at room temperature. Detailed description

[0020] The subject of the present application is a cosmetic or dermatological emulsion of moderate to fluid, or even very fluid, viscosity, which can then be sprayed, the emulsifier of which is mainly, or even exclusively, composed of ingredients of plant origin chosen from cyclodextrins and starchy and / or starchy emulsifiers. The emulsion is made possible by the combination of a cyclodextrin and a starchy and / or starchy emulsifier, which can make it possible not to add additional emulsifying surfactants, such as emulsifiers of petrochemical origin or emulsifying co-surfactants of petrochemical origin or of natural origin. An emulsion according to the subject of the present application has the advantage of being able to comprise an advantageously reduced quantity of emulsifier of petrochemical origin of low molecular weight, or even of not comprising said emulsifiers at all.

[0021] The Applicant has been able to observe that the oil-in-water emulsions formed by combining a cyclodextrin with an emulsifier containing starch and / or of starch origin, such as for example a starch octenyl succinate, advantageously have Brookfield viscosities, at 20°C and 20 rpm for 1 minute, of less than 3000 mPa.s, and are also stable. For a viscosity of 3000 mPa.s, the emulsion has the consistency of a gel. By adjusting the quantities of cyclodextrin and emulsifier of starch origin, it is advantageously possible to modify the viscosity of the emulsions formed: down to less than 1000 mPa.s or less than 100 mPa.s, i.e. fluid enough to be applied by spraying, and even down to less than 10, i.e. very fluid. Emulsions can therefore have varied textures.

[0022] The emulsions according to the present application may consist of drops of spherical or oblong shape, of size less than 30 pm, or even less than 10 pm. The adjustable viscosity, combined with the drop size less than 30 pm, or even 10 m, allows you to obtain advantageously varied textures, ranging from cream to lotion to milk.

[0023] Emulsion

[0024] 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.

[0025] An object of the present application is an oil-in-water emulsion comprising: - an oily phase dispersed in an aqueous phase, - an emulsifying system consisting of at least one cyclodextrin and at least one starchy and / or starchy-origin emulsifier, said emulsion having a Brookfield viscosity, at 20°C at 20 rpm for 1 min with the SP5 spindle, of less than 3,000 mPa.s, preferably less than or equal to 2,800 mPa.s, preferably less than or equal to 2,600 mPa.s, and in which the starchy and / or starchy-origin emulsifier has a solubility in water at 22°C according to test A of greater than or equal to 50%, or greater than or equal to 75%, or greater than or equal to 85%, or greater than or equal to 95%, or greater than or equal to 98%, or greater than or equal to 99%, or equal to 100%.

[0026] Preferably, the oil-in-water emulsion comprises a mass content of said at least one cyclodextrin relative to the total weight of the emulsion in a range from 2.5 to 6% by weight, from 3 to 5% by weight, and most preferably from 3.5 to 4.5% by weight of emulsion, or from 2.5 to 4% by weight.

[0027] Preferably, the oil-in-water emulsion comprises a mass content of said at least one starchy emulsifier and / or of starchy origin by relative to the total weight of the emulsion in a range from 1 to 7% by weight, from 1.5 to 6% by weight, from 2 to 5% by weight, and most preferably from 2.5 to 4.5% by weight of emulsion, or from 1.0 to 2.5% by weight.

[0028] Preferably, the oil-in-water emulsion contains an amount of native or modified granular starch, preferably amphiphilic modified granular starch, more preferably octenyl succinate granular starch, less than or equal to 5% by weight, preferably less than or equal to 2% by weight, more preferably less than or equal to 1% by weight, even more preferably less than or equal to 0.5% by weight, and most preferably equal to 0% by weight, relative to the total weight of the emulsion.

[0029] Preferably, the emulsifying system is the one and only emulsifier present in the emulsion.

[0030] Cyclodextrin

[0031] 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.

[0032] 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.

[0033] The preferred cyclodextrins according to the present invention are alpha-, beta- and gamma-cyclodextrins, with native beta-cyclodextrin being the most preferred. The cyclodextrin may in particular be in the form of a crystalline, pseudo-crystalline or amorphous powder. Examples of cyclodextrins useful for the emulsion which is the subject of the present application are those marketed by the applicant under the reference “Beauté by Roquette® CD 102” or “Beauté by Roquette Roquette® CD 100”.

[0034] Among the cyclodextrins useful for the present invention as described above, it will be possible to select cyclodextrins whose size distribution has a volume average diameter of between 5 microns and 300 microns, preferably between 10 microns and 250 microns, more preferably between 10 microns and 100 microns. Still among the cyclodextrins useful for the present invention, it is also possible to select cyclodextrins having water contents ranging from 0.5 to 20% by weight of crude cyclodextrin, preferably from 1 to 15%, and more preferably from 3 to 13%. Finally, it is possible to select cyclodextrins by combining the above size distribution and water content characteristics.

[0035] Without being bound by a theory, the applicant believes that the cyclodextrins of the emulsifying system useful for the oil-in-water emulsions according to the present application make it possible to obtain stable emulsions, that is to say that they give these emulsions a stability of at least 24 hours, or at least 48 hours, or at least 1 week, or at least 1 month, or at least 6 months, or at least 12 months, or at least 24 months. By "stable" is meant the absence of creaming or marbling visible to the naked eye.

[0036] According to one embodiment, the mass content of cyclodextrin relative to the total weight of the emulsion is within a range from 2.5 to 6% by weight, from 3 to 5% by weight, and most preferably from 3.5 to 4.5% by weight of emulsion, or from 2.5 to 4% by weight.

[0037] Starchy and / or starchy emulsifier

[0038] By "starchy emulsifier" is meant a starch having emulsifying properties, in particular having the capacity to emulsify an oil in water. A starchy emulsifier useful in the invention is thus a starch modified by a hydrophobic functionalization, or an amphiphilic functionalization, or a combination of these functionalizations. The starch undergoing at least one of said functionalizations may be a native starch or better still a modified starch thermally or enzymatically, the thermally or enzymatically modified starch being able to be a pregelatinized, gelatinized, atomized, hydrolyzed starch.

[0039] According to one embodiment, the starch undergoing at least one of said functionalizations is a native starch. According to another preferred embodiment, the starch undergoing at least one of said functionalizations is a pregelatinized starch. According to another preferred embodiment, the starch undergoing at least one of said functionalizations is a hydrolyzed starch.

[0040] "Starchy emulsifier" means a dextrin, or a hydrolyzed starch, or a maltodextrin, having the capacity to emulsify an oil in water. A starch emulsifier may be a dextrin, a hydrolyzed starch, or a maltodextrin, having undergone hydrophobic functionalization, or amphiphilic functionalization, or a combination of these functionalizations.

[0041] The term "hydrophobic and / or amphiphilic functionalization" refers to a chemical reaction between, on the one hand, a hydrophobic and / or amphiphilic reagent, and on the other hand, some or all of the hydroxyl groups of the starch or starchy material. This reaction is generally a "substitution" or "grafting" by creating covalent bonds of the ester, ether or amide type.

[0042] According to a so-called "amphiphilic" embodiment, the starchy emulsifier, or the emulsifier of starchy origin, is obtained by esterification of the hydroxyl groups by reaction with an acyl chloride (RC(=O)CI), or with an alcohol ester (RC(=O)OR') or an acid anhydride (RC(=O))2O or (RC(=O)OC(=O)R ').

[0043] The acyl chloride may be a chloride obtained from one of the following carboxylic acids (RC(=O)OH), where R is a saturated or unsaturated aliphatic group, said acid having from 2 to 24 carbons, preferably 4 to 24 carbons, and more preferably among propionic acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid, pelargonic acid, octanoic acid, decanoic acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, oleic acid, stearic acid, the anhydrides of these acids, the mixed anhydrides of these acids, and any mixtures of these products.

[0044] The alcohol may be a linear, branched, or cyclic alcohol, consisting of a carbon skeleton with at least 2 carbon atoms. The alcohol may have at least one unsaturation, i.e., at least one carbon-carbon double bond. The alcohol may be a linear, branched, or cyclic fatty alcohol, consisting of a carbon skeleton with 8 to 36 carbon atoms. The fatty alcohol may have at least one unsaturation. Examples of fatty alcohols without unsaturation are octanol, nonanol, decanol, undecanol, dodecanol, tetradecanol, hexadecanol, octadecanol, docosanol, policosanol.

[0045] The acid anhydride may be an anhydride of one of the polycarboxylic acids described below.

[0046] The polycarboxylic acid may be a linear, branched, or cyclic polycarboxylic acid, consisting of a carbon skeleton containing at least 2 carbon atoms. The polycarboxylic acid may comprise at least one unsaturation, i.e., at least one carbon-carbon double bond, such as, for example, maleic acid, glutaconic acid, or fumaric acid. The polycarboxylic acid may also comprise at least one alcohol group attached to the carbon chain. The polycarboxylic acid may comprise at least two carboxylic acid groups. According to one embodiment, the polycarboxylic acids are linear dicarboxylic acids carrying the acid groups at the ends of the carbon chain.Examples of linear dicarboxylic acids are ethanedioic acid (or oxalic acid), propanedioic acid, butanedioic acid (or succinic acid), dihydroxybutanedioic acid (or tartaric acid), 2-hydroxybutanedioic acid (or malic acid), pentanedioic acid (or glutaric acid), hexanedioic acid (or adipic acid), tetrahydroxyhexanedioic acid (or saccharic acid), gluconic acid, heptanedioic acid (or pimelic acid), octanedioic acid, nonanedioic acid, decanedioic acid (or sebacic acid).

[0047] In one embodiment, the acid anhydride is a linear dicarboxylic acid anhydride. In one embodiment, the acid anhydride is succinic anhydride.

[0048] According to one embodiment, the acid anhydride is a succinic acid anhydride, in particular substituted by a saturated or unsaturated alkyl chain, such as octenylsuccinic anhydride, or dodecylsuccinic anhydride.

[0049] The level of functionalization can result in solubility of the functionalized starch. If the solubility is insufficient, a pregelatinization treatment can be applied to the functionalized starch to make it sufficiently soluble.

[0050] The starch may be tuber, legume or cereal starch, or a mixture of at least two of these starches. For example, the starch may be wheat, corn, potato, pea, bean, rice starch, or a mixture of at least two of these starches. The dextrin, hydrolyzed starch, and maltodextrin may be derived from one of said starches. Said starches may also be starches rich in amylopectin. Preferably, the starch is not a millet starch. More preferably, the starch is chosen from starches comprising at least 90% by weight of amylopectin relative to the weight of starch, preferably at least 95%, preferably at least 98%, and most preferably at least 99%.Even more preferably, the starch is a corn starch rich in amylopectin, and most preferably, the starch is a waxy corn starch, that is to say a starch whose polymer chains comprise at least 99% amylopectin by weight.

[0051] According to one embodiment, the emulsifying starch is a waxy starch functionalized by an alkenyl succinate group, in particular octenyl succinate or dodecyl succinate. Examples of starches carrying octenyl succinate functions are Cleargum® CO 01 and CO 03 marketed by Roquette. These starches are hydrolyzed starches, and are known to be water-soluble, i.e. soluble in water, and to allow the preparation of conventional emulsions.

[0052] According to one embodiment, the starch octenyl succinate useful in the emulsion and the process which are the subject of the present application, is in the form of a sodium, calcium or aluminum salt, preferably in the form of a sodium or calcium salt, and more preferably in the form of a sodium salt.

[0053] According to another embodiment, the emulsifier of starchy origin is a dextrin which has undergone octenyl succinate functionalization, such as for example Cleargum® CO A1 marketed by Roquette. This dextrin is also known to be water-soluble and allows the preparation of classic emulsions.

[0054] According to a so-called “hydrophobic” embodiment, the emulsifying starch, or the emulsifier of starchy origin, is obtained by grafting purely hydrophobic groups by radical reaction, for example as set out in the applicant's application EP3180372.

[0055] According to one embodiment, the emulsifiers of starchy origin have a weight-average molecular mass, measured by HPSEC-MALLS, ranging from 10 to 2,000 kDa, or from 20 to 1,500 kDa, or from 30 to 1,000 kDa, or from 40 to 800 kDa, or from 45 to 700 kDa.

[0056] The weight-average molecular mass, denoted Mw, is determined by a person skilled in the art using size exclusion chromatography of the HPSEC-MALLS type (High Performance Size Exclusion Chromatography coupled online with Multiple Angle Laser Light Scattering). This mass can be measured by size exclusion chromatography, according to the following protocol: - preparation of a sample by solubilization of a sample of emulsifier of starchy origin, by heating at 100°C for 30 min in a dilution solvent consisting of a DMSO / NaNO3 mixture (0.1 M of NaNO3 in DMSO), said sample being able to have a concentration ranging from 2 to 10 mg of sample of emulsifier of starchy origin per mL of dilution solvent; - use of a high-performance liquid chromatography (HPLC) device equipped with a pump, operating in isocratic mode, circulating an elution solvent at 0.3 mL / min, a refractometer, an 18-angle multiple angle light scattering laser detector heated to 35°C, for example a DAWN DSP detector from Wyatt, and a column thermostatization oven heated to 35°C, for example equipped with SUPREMA-type polyhydroxymethacrylate columns and whose elution solvent is, for example, a 0.1 M aqueous sodium nitrate solution, containing 0.02% by mass of sodium azide; - injection into the device of a sample volume of approximately 100pL.

[0057] Weight- and number-average molecular masses can be determined from the obtained spectra, for example, by reprocessing the spectra in 1st order exponential, using ASTRA v.4 type analysis software.

[0058] According to one embodiment, the starchy or starch-derived emulsifiers have a solubility in water at 22°C according to the following test A, greater than or equal to 50%, or greater than or equal to 75%, or greater than or equal to 85%, or greater than or equal to 95%, or greater than or equal to 98%, or greater than or equal to 99%, or equal to 100%. Starchy emulsifiers having solubilities in water in these ranges of values ​​are amphiphilic and pregelatinized modified starches, amphiphilic and atomized modified starches, amphiphilic and acid-hydrolyzed modified starches, and amphiphilic and enzymatically hydrolyzed modified starches. Thus the starchy or starchy emulsifier may be chosen from a pregelatinized starch octenyl succinate, a gelatinized starch octenyl succinate, a hydrolyzed starch octenyl succinate, a hydrolyzed and pregelatinized starch octenyl succinate, and mixtures thereof.

[0059] According to one embodiment, the emulsifying system contains an amount of native or modified granular starch, preferably amphiphilic modified granular starch, more preferably octenyl succinate granular starch, less than or equal to 5% by weight, preferably less than or equal to 2% by weight, more preferably less than or equal to 1% by weight, even more preferably less than or equal to 0.5% by weight, and most preferably equal to 0% by weight, relative to the weight of said starchy or starchy emulsifier.

[0060] Without being bound by a theory, the applicant considers that the use of a water-soluble starchy emulsifier or emulsifier of starchy origin, in particular whose solubility in water is at least 50% at 22°C according to test A, preferably greater than or equal to 98%, preferably greater than or equal to 99%, more preferably equal to 100%, possibly combined with at least one of the following characteristics: - the selection of a mass content of cyclodextrin in the emulsion in a range from 2.5 to 4% by weight of emulsion, - the selection of a mass content of starchy or starchy emulsifier in a range from 1.0 to 2.5% by weight of emulsion, makes, or makes, possible the preparation of oil-in-water emulsions having moderate viscosities, i.e. less than or equal to 3000 mPa.s, to low viscosities, i.e. less than or equal to 1000 mPa.s, or even very low viscosities, i.e. less than or equal to 100 mPa.s.

[0061] When the starchy emulsifier is a starch and has a solubility according to test A equal to 100%, almost no starch granules, otherwise no solid starch particles, are visible in the aqueous phase under observation under an optical microscope, because all the starch granules have been deconstructed and transformed into anhydroglucose polymer chains solubilized in the aqueous phase. Amphiphilic modified starches that are pregelatinized or atomized or hydrolyzed by acid or enzymatic means are in fact sufficiently soluble in water to be solubilized without resorting to cooking with water vapor. Their dispersion in water in a stirred enclosure, possibly by heating, for example by a double jacket or by a dipping coil, allows their complete dissolution in water, preferably at a temperature ranging from 10°C to 60°C, or from 15°C to 60°C, or from 20°C to 60°C, or from 20°C to 50°C, or from 20°C to 40°C.On the contrary, granular starches in general, as well as amphiphilic modified granular starches, and specifically amphiphilic modified granular starches that are not pregelatinized or not atomized or not hydrolyzed by acid or enzymatic means, require heating to a temperature between 60°C and 150°C, often between 70-80°C and 120°C. Most often this heating is done by “cooking” with water steam at 100-150°C and 1-5 bars, which requires special equipment such as a water steam nozzle and a specific stirred tank adapted to the stirring of the viscous starch gel obtained by cooking with water steam.

[0062] Examples of water-soluble starches with octenyl succinate functions and pregelatinized starches are Cleargum® CO 01 and CO 03 marketed by Roquette. These octenyl succinate starches have a solubility in water at 22°C according to test A close to 100%, or even equal to 100%.

[0063] Solubility is measured using test A, which consists of the following method: - take a test sample mass (m test sample) of approximately 5.0 g of starchy emulsifier sample, this mass being expressed as dry mass; - dispersion of this mass in 200 mL of water at 22°C in an Erlenmeyer flask, which is then placed at 22°C in a water bath for 4 hours under magnetic stirring with stirring for 5 minutes every 30 minutes; - Filtration of the contents of the bottle on a filter with a porosity of 8 pm, for example of the Whattamn 2 V type; - pipetting 50 mL of filtrate and introducing this quantity into a dry, tared crystallizer; - evaporation of the water from the crystallizer by heating at 60°C for 45 minutes, then at 130°C for 90 minutes; - after cooling in a desiccator, weigh the mass of emulsifier of starchy origin obtained after drying (m dry extract).

[0064] Solubility is calculated as follows:

[0065] Solubility = [m dry extract x 200 x 100] / [50 xm test sample]

[0066] The dry mass of the test portion is calculated according to ISO 1666:1996.

[0067] According to one embodiment, the starchy or starchy emulsifiers have a degree of substitution in hydrophobic and / or amphiphilic groups ranging from 0.001 to 3, or from 0.01 to 2.8, or from 0.015 to 2.6. According to another embodiment, the degree of substitution in hydrophobic and / or amphiphilic groups ranges from 0.001 to 0.1, or from 0.01 to 0.10, or from 0.015 to 0.05. For example, for starchy or starchy emulsifiers functionalized by an octenyl succinate type group, the degree of substitution will be deduced from the measurement of the quantity of octenylsuccinate groups fixed on said emulsifier, which is determined by gas chromatography on a sample derivatized in methyl form and with an internal calibration. The chromatography column is a J&W Scientific DB1 capillary column or equivalent. Derivatization in methyl form is done by transesterification with hydrochloric methanol followed by extraction with chloroform.The internal standard is methyl laurate. The amount of octenylsuccinate groups attached to said emulsifier. starchy or of starchy origin is then expressed as a percentage by weight relative to the gross mass of the sample of said emulsifier.

[0068] According to one embodiment, the mass content of starchy emulsifier and / or emulsifier of starchy origin relative to the total weight of the emulsion is within a range from 1 to 7% by weight, from 1.5 to 6% by weight, from 2 to 5% by weight, and most preferably from 2.5 to 4.5% by weight of emulsion, or from 1.0 to 2.5% by weight.

[0069] Emulsifying co-surfactant of petrochemical origin

[0070] The term "emulsifying co-surfactant of petrochemical origin" means an emulsifying surfactant of petrochemical origin added to the emulsion in addition to the emulsifying system consisting of a cyclodextrin and an emulsifier of starch origin already present, and in a quantity less than that which would be required if said emulsifying surfactant of petrochemical origin were the only emulsifier present in the emulsion. The term "emulsifying surfactant of petrochemical origin" means any molecule or macromolecule derived from raw materials originating solely from petrochemicals.

[0071] Among the emulsifying surfactants of petrochemical origin, mention will be made of glycol derivatives, and in particular ethoxylated and polyethoxylated derivatives of glycols.

[0072] Naturally sourced emulsifying O / W co-surfactant

[0073] In this Application, the term "O / W emulsifying co-surfactant of natural origin" means an oil-in-water emulsifying surfactant of natural origin added to the emulsion in addition to the emulsifying system consisting of a cyclodextrin and a starchy and / or starchy emulsifier already present, and in a quantity less than that which would be required if said emulsifying surfactant were the only emulsifier present in the emulsion. "O / W emulsifying oil-in-water surfactant of natural origin" means any molecule derived from renewable resources, in particular extracted from, or secreted by, plants, microorganisms or algae and capable of allowing, after physical, chemical or enzymatic modification, the production of an O / W oil-in-water emulsion or of promoting its stability.

[0074] This natural origin O / W emulsifying co-surfactant can also be chosen from products that are naturally biodegradable in a hydrated natural environment, with in particular a Hydrophilic-Lipophilic balance (HLB) of between 8 and 20, preferably between 9 and 16, and even better between 11 and 14.

[0075] By way of example, this O / W emulsifying co-surfactant of natural origin 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.

[0076] The O / W emulsifying co-surfactant of natural origin 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.

[0077] The O / W emulsifying co-surfactant of natural origin 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 (as Dermofeel® G 5 DO from Evonik Dr. Straetmans GmbH), Polyglyceryl-2 Caprate of HLB about 9 (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 about 15 (as Dermofeel® G 6 CY from Dr.Straetmans GmbH I Evonik), Polyglyceryl-10 Laurate from HLB approx. 16 (like Dermofeel® G 10 L from Dr. Straetmans GmbH I Evonik).

[0078] The O / W emulsifying co-surfactant of natural origin can be chosen from alkyl polyglucosides, sometimes also called alkyl polyglycosides, and designated by the acronym APG. These emulsifiers are non-ionic surfactants well known in themselves. 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): R1 -O-(R2-O)p-(S)n

[0079] In which: - S represents a reducing saccharide, which can contain between 5 and 6 carbon atoms, - R1 denotes a linear or branched alkyl and / or alkenyl radical containing approximately 8 to 24 carbon atoms, or an alkylphenyl radical whose linear or branched alkyl group contains approximately 8 to 24 carbon atoms, - R2 denotes an alkylene radical containing 2 to 4 carbon atoms, - n denotes a value ranging from 1 to 15, - p denotes a value ranging from 0 to 10.

[0080] By reducing saccharide, we mean in formula (I), the saccharide derivatives which do not have a glycosidic bond in their structures 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 present itself in any form of isomerism, whether optical isomerism, geometric isomerism or positional isomerism; it can also represent a mixture of isomers.

[0081] According to a particular aspect of the present invention, 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.

[0082] A first preferred variant of alkyl polyglucosides according to the present invention 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.

[0083] A second preferred variant of alkyl polyglucosides according to the present invention 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

[0084] Alkyl polyglucosides of formula (I) are commercially available under the names: Plantacare® 810 UP (R1 is C8-C10 / INCI: caprylyl / capryl glucoside), Plantacare® 818 UP (R1 is C8-C16 / INCI: Coco- glucoside), Plantacare® 2000 UP (R1 is C8-C16 I INCI: decyl glucoside) and Plantacare® 1200 UP (R1 is C12-C16 I INCI: lauryl glucoside) sold by BASF; Macanol® 810 (R1 is C8-C10), Macanol® 1200 (R1 is C12-C14), Macanol® 816 (mixture of R1 is C8, C10, C12, C14, C16) sold by FCI Technology; Neocare MF 0718 (R1 is C8-C10 I INCI: caprylyl / capryl glucoside), Neocare MF 0012 (R1 is C12-C14 I INCI: lauryl glucoside), Neocare MF 0002 (R1 is C8-C16 / INCI: decyl glucoside), Neocare MF 818 (R1 is C8-C16 / INCI: coco glucoside) sold by Neochem; Tego Care CG 90 (R1 is C14-C16 I INCI: cetearyl glucoside) sold by Evonik Healthcare.

[0085] The O / W emulsifying co-surfactant 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 invention described above. Regarding 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.

[0086] Mixtures of alkyl glucosides and fatty alcohols useful in the invention 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).

[0087] Pickering emulsion

[0088] The emulsion according to the present application may also be a Pickering type emulsion.

[0089] Pickering emulsions are stabilized by colloidal particles such as silicas, talc or insoluble granular starches, which are placed at the interfaces of the continuous phase and the dispersed phase. In the context of the present invention, these colloidal particles are particles organic particles formed by in-situ precipitation from inclusion complexes between at least one cyclodextrin and at least one fatty molecule present in the emulsion, which may be derived from the oil constituting the emulsion. These particles are very advantageously compatible with skin or hair and do not damage animal cell membranes. Without being bound by a theory, it is possible that the emulsifier of starchy origin contributes to forming or stabilizing the Pickering emulsion thus formed.

[0090] Mixed emulsion

[0091] The emulsion according to the present invention can also be a mixed emulsion, that is to say it can be both and jointly stabilized by amphiphilic molecules like conventional emulsions and by organic particles formed by in-situ precipitation of inclusion complexes between at least one cyclodextrin and at least one fatty molecule present in the emulsion.

[0092] Oily phase

[0093] The oily phase includes: - at least one oil, chosen from non-volatile oils or volatile oils, - and / or at least one wax, chosen from polar hydrocarbon waxes, ester waxes, alcohol waxes, apolar hydrocarbon waxes, or silicone waxes.

[0094] Oil

[0095] The term “oil” means any fatty substance in liquid form at room temperature (25°C) and atmospheric pressure (1.013.105 Pa).

[0096] Non-volatile oils

[0097] As indicated above, the oil-in-water emulsion according to the invention comprises at least one non-volatile oil. More particularly, the non-volatile oil is chosen from non-volatile silicone oils, from non-volatile hydrocarbon oils, polar or apolar, as well as mixtures thereof; and preferably from non-volatile polar oils, in particular chosen from C10-C26 alcohols, ester oils, vegetable oils, alone or in mixtures.

[0098] By "hydrocarbon oil" is meant an oil formed essentially, or even consisting of, carbon and hydrogen atoms, and possibly atoms oxygen, nitrogen, and not containing any silicon or fluorine atoms. Hydrocarbon oil is therefore distinct from a silicone oil and a fluorinated oil. For the purposes of the invention, the term "silicone oil" means an oil comprising at least one silicon atom, and in particular at least one Si-O group. Non-volatile means oils whose vapor pressure is less than 2.66 Pa, preferably less than 0.13 Pa (measurement according to OECD standard 104 of 27 / 07 / 95).

[0099] Polar non-volatile hydrocarbon oils

[0100] Preferably, the oil-in-water emulsion according to the invention comprises at least one polar hydrocarbon non-volatile oil. This hydrocarbon oil may contain alcohol, ester, ether, carboxylic acid, amine and / or amide groups. Preferably, the hydrocarbon oil is free of heteroatoms such as nitrogen, sulfur and phosphorus. In the present case, the polar hydrocarbon non-volatile oil comprises at least one oxygen atom. In particular, this polar hydrocarbon non-volatile oil comprises at least one alcohol function (it is then an “alcohol oil”) or at least one ester function (it is then an “ester oil”). The ester oils that can be used in the oil-in-water emulsion according to the invention may in particular be hydroxylated. Thus, the oil-in-water emulsion comprises one or more polar hydrocarbon non-volatile oils, in particular chosen from:

[0101] (1) C10-C26 alcohols, preferably monoalcohols: C10-C26 alcohols are saturated or unsaturated, branched or unbranched, and comprise from 10 to 26 carbon atoms, preferably from 14 to 24 carbon atoms. Examples of fatty alcohols that can be used according to the invention include linear or branched fatty alcohols of synthetic origin, or natural, such as alcohols from plant materials (copra, palm kernel, palm, etc.) or animal materials (tallow, etc.). Of course, other long-chain alcohols can also be used, such as ether alcohols or so-called Guerbet alcohols. Finally, we can also use certain more or less long cuts of alcohols of natural origin, such as coconut (C12 to C16) or tallow (C16 to C18) or compounds such as diols or cholesterol.As particular examples of fatty alcohols which can be used preferably, mention may in particular be made of lauryl alcohol, isostearyl alcohol, oleyl alcohol, 2-butyloctanol, 2-undecyl pentadecanol. 2-hexyldecyl alcohol, isocetyl alcohol, octyldodecanol and mixtures thereof. According to an advantageous embodiment of the invention, the alcohol is chosen from octyldodecanol.

[0102] (2) monoesters, diesters, triesters, optionally hydroxylated, of a C2-C8 mono or polycarboxylic acid and a C2-C8 alcohol. In particular: (2.1) monoesters of a C2-C8 carboxylic acid and a C2-C8 alcohol, optionally hydroxylated, (2.2) diesters of a C2-C8 dicarboxylic acid and a C2-C8 alcohol, optionally hydroxylated; such as diisopropyl adipate, 2-diethylhexyl adipate, dibutyl adipate, 2-diethylhexyl succinate, (2.3) triesters of a C2-C8 tricarboxylic acid and a C2-C8 alcohol, optionally hydroxylated, such as citric acid esters, such as trioctyl citrate, triethyl citrate, acety Itributy I citrate, tributy I citrate.

[0103] (3) esters of a C2-C8 polyol and one or more C2-C8 carboxylic acids: such as glycol monoacid diesters, such as neopentyl glycol diheptanoate, or glycol monoacid triesters such as triacetin.

[0104] (4) ester oils, in particular having between 17 and 70 carbon atoms: examples include mono-, di- or triesters. Ester oils may be hydroxylated or not. The non-volatile ester oil may be chosen, for example, from:

[0105] (4.1) monoesters comprising between 17 and 40 carbon atoms in total, in particular monoesters of formula R1 -COO-R2 in which R1 represents the residue of a linear or branched or aromatic fatty acid comprising from 4 to 40 carbon atoms, saturated or unsaturated, and R2 represents a hydrocarbon chain, in particular a branched chain, containing from 3 to 40 carbon atoms provided that R1 +R2 is greater than or equal to 17, such as, for example, Purcellin oil (cetostearyl octanoate), isononyl isononanoate, C12 to C15 alcohol benzoate, 2-ethylhexyl palmitate, octyldodecyl neopentanoate, 2-octyldodecyl stearate, 2-octyldodecyl erucate, isostearate isostearyl, 2-octyldodecyl benzoate, octanoates, decanoates or ricinoleates of alcohols or polyalcohols, isopropyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, 2-ethylhexyl palmitate, 2-hexyldecyl laurate, 2-octyldecyl palmitate, 2-octyldodecyl myristate. Preferably, these are esters of formula R1 -COO-R2 in which R1 represents the residue of a linear or branched fatty acid comprising from 4 to 40 carbon atoms and R2 represents a hydrocarbon chain, in particular a branched one, containing from 3 to 40 carbon atoms, R1 and R2 being 10 such that R1 +R2 is greater than or equal to 17. Even more particularly, the ester comprises between 17 and 40 carbon atoms in total. Preferred monoesters include isononyl isononanoate, isopropyl palmitate, oleyl erucate and / or octyl-2-docecyl neopentanoate.

[0106] (4.2) fatty acid monoesters, in particular of 18 to 22 carbon atoms, and in particular of oleic acid, lauric acid, stearic acid, and diols, such as propylene glycol monostearate.

[0107] (4.3) diesters, in particular comprising between 18 and 60 carbon atoms in total, in particular between 18 and 50 carbon atoms in total. It is possible in particular to use diesters of dicarboxylic acid and monoalcohols, such as preferably diisostearyl malate; or diesters of monocarboxylic acid and dialcohols, such as 1,3-propanediyl ester of octanoic acid (or propanediol dicaprylate), sold under the name DUB ZENOAT by the company Stéarinerie Dubois; or diesters of glycol and monocarboxylic acids, such as neopentyl glycol diheptanoate, propylene glycol dioctanoate, diethylene glycol diisononanoate, or polyglyceryl-2 diisostearate (in particular such as the compound sold under the commercial reference DERMOL DGDIS by the company Alzo);

[0108] (4.4) hydroxylated monoesters and diesters, preferably having a total carbon number ranging from 18 to 70, such as polyglyceryl-3 diisostearate, isostearyl lactate, octylhydroxystearate, octyldodecyl hydroxystearate, diisostearyl malate, glycerin stearate;

[0109] (4.5) triesters, in particular comprising between 35 and 70 carbon atoms in total, in particular such as tricarboxylic acid triesters, such as triisostearyl citrate, or tridecyl trimellitate, or triesters of glycol and monocarboxylic acids such as polyglycerol-2 triisostearate;

[0110] (4.6) tetraesters, in particular having a total carbon number ranging from 35 to 70, such as tetraesters of penthaerythritol or polyglycerol and a monocarboxylic acid, for example such as pentaerythrityl tetrapelargonate, pentaerythrityl tetraisostearate, pentaerythrityl tetraisononanoate, glyceryl tri-2-decyl tetradecanoate, polyglyceryl-2-tetraisostearate or pentaerythrityl tetra-2-decyl tetradecanoate;

[0111] (4.7) polyesters obtained by condensation of dimer and / or trimer of unsaturated fatty acid and diol such as those described in patent application FR 0 853634, such as in particular dilinoleic acid and 1,4-butanediol. In this respect, mention may be made in particular of the polymer marketed by Biosynthis under the name Viscoplast 14436H (INCI name: dilinoleic acid / butanediol copolymer), or copolymers of polyols and dimer diacids, and their esters, such as Hailucent ISDA;

[0112] (4.8) esters and polyesters of dimer diol and mono- or dicarboxylic acid, such as esters of dimer diol and fatty acid and esters of dimer diols and dimer dicarboxylic acid, in particular obtainable from a dimer dicarboxylic acid derived in particular from the dimerization of an unsaturated fatty acid in particular C8 to C34, in particular C12 to C22, in particular C16 to C20, and more particularly C18, such as esters of dilinoleic diacids and dilinoleic diol dimers, for example such as those marketed by the company NIPPON FINE CHEMICAL under the trade name LUSPLAN DD-DA5® and DD-DA7®;

[0113] (4.9) polyesters resulting from the esterification of at least one triglyceride of hydroxylated carboxylic acid(s) by an aliphatic monocarboxylic acid and by an aliphatic dicarboxylic acid, optionally unsaturated, such as succinic acid and isostearic acid castor oil marketed under the reference Zenigloss by Zenitech;

[0114] (4.10) vegetable hydrocarbon oils such as fatty acid triglycerides (liquid at room temperature), in particular fatty acids having 7 to 40 carbon atoms, such as triglycerides of heptanoic or octanoic acids, in particular, mention may be made of saturated triglycerides such as caprylic / capric triglyceride and mixtures thereof, for example such as that marketed under the reference Myritol 318 from Cognis, glyceryl triheptanoate, glycerin trioctanoate, C18-36 acid triglycerides such as those marketed under the reference DUB TGI 24 marketed by Stéarineries Dubois), jojoba oil, macadamia oil, apricot kernel oil, as well as unsaturated triglycerides such as castor oil, olive oil, ximenia oil, pracaxi oil; and other vegetable hydrocarbon oils such as Japanese Camellia seed oil, 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, peanut oil.

[0115] (4.11) and mixtures thereof, such as oils consisting of a mixture of C8-C10 fatty acid monoesters and C12-C18 fatty alcohols, such as MIGLYOL Coco 810 from IOI Oleo GmbH (INCI name: coco-Capyrlate / Caprate).

[0116] In a particular embodiment of the invention, the oil-in-water emulsion does not comprise vegetable oil.

[0117] In a particular embodiment of the invention, the oil-in-water emulsion does not comprise canola oil.

[0118] Preferably, the polar non-volatile hydrocarbon oil(s) are chosen from C10-C26 monoalcohols, ester oils, and in particular monoesters comprising at least 17 carbon atoms in total, diesters, hydroxylated or not, comprising at least 18 carbon atoms in total, triesters, in particular having at least 35 carbon atoms, tetraesters, in particular having at least 35 carbon atoms, vegetable hydrocarbon oils, and mixtures thereof.

[0119] Non-volatile non-polar hydrocarbon oils

[0120] As regards non-volatile apolar oils, we can particularly mention paraffin oil, squalane, pentadecane, nonadecane, eicosane, isoeicosane, polybutenes, hydrogenated or not, polyisobutenes, hydrogenated or not, polydecenes, hydrogenated or not, copolymers decene / butene, polybutene / polyisobutene copolymers, and mixtures thereof. An example of a mixture of non-volatile non-polar hydrocarbon oils is the product Emogreen L15 sold by Seppic, which is a mixture of C15-C19 alkanes.

[0121] Non-volatile silicone oils

[0122] As regards non-volatile silicone oils, examples include non-phenylated non-volatile silicone oils, such as polydimethylsiloxanes.

[0123] Phenyl silicone oils may also be mentioned, such as diphenyl dimethicone, phenyl trimethicone, trimethylsiloxyphenyl dimethicone, diphenylsiloxy phenyl trimethicone, trimethyl pentaphenyl trisiloxane, or tetramethyl tetraphenyl trisiloxane, as well as mixtures thereof. Advantageously, the non-volatile silicone oil does not comprise any C2-C3 oxyalkylenated group(s) (oxyethylenated, oxypropylenated), nor any glycerol group(s).

[0124] According to a particular embodiment of the invention, the non-volatile oil is chosen from polar non-volatile oils, in particular chosen from C10-C26 alcohols, ester oils, vegetable oils, alone or in mixtures. Thus, as indicated previously, the oil-in-water emulsion comprises at least one C10-C26 alcohol, preferably C14-C24. The mass percentage of non-volatile oils represents more particularly from 4 to 65% by weight, preferably from 5% to 60%, more preferably from 10 to 30% by weight, relative to the weight of the oil-in-water emulsion.

[0125] Volatile oils

[0126] The oil-in-water emulsion according to the invention may optionally comprise at least one volatile oil. For the purposes of the invention, the term "volatile oil" denotes oils having in particular a non-zero vapor pressure, at room temperature and atmospheric pressure, in particular having a vapor pressure ranging from 2.66 Pa to 40,000 Pa), in particular ranging from 2.66 Pa to 13,000 Pa, and more particularly ranging from 2.66 Pa to 1,300 Pa. The volatile oils may be hydrocarbon-based or silicone-based.

[0127] Among the volatile non-polar hydrocarbon oils having from 8 to 16 carbon atoms, mention may in particular be made of branched C8-C16 alkanes such as C8-C16 isoalkanes (also called isoparaffins), isododecane, isodecane, isohexadecane and for example the oils sold under the trade names Isopars or Permetyls. Preferably, the volatile hydrocarbon oil is chosen from volatile hydrocarbon oils having from 8 to 16 carbon atoms and their mixtures, in particular from isododecane, isodecane, isohexadecane, and is in particular isohexadecane.Mention may also be made of volatile linear alkanes comprising from 8 to 16 carbon atoms, in particular from 10 to 15 carbon atoms, and more particularly from 11 to 13 carbon atoms, for example such as n-dodecane (C12) and n-tetradecane (C14) sold by Sasol respectively under the references PARAFOL 12-97 and PARAFOL 14-97, as well as their mixtures, the undecane-tridecane mixture, such as Cetiol Ultimate from BASF, the mixtures of n-undecane (CH) and n-tridecane (C13) obtained in examples 1 and 2 of application WO 2008 / 155059 from Cognis, and their mixtures, as well as ethers having a maximum of 16 carbon atoms, such as for example dicaprylylether.

[0128] Examples of volatile silicone oils include linear volatile silicone oils such as hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, tetradecamethylhexasiloxane, hexadecamethylheptasiloxane and dodecamethylpentasiloxane. Examples of volatile cyclic silicone oils include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopenta-siloxane and dodecamethylcyclohexasiloxane.

[0129] Advantageously, if the oil-in-water emulsion comprises them, the content of volatile oil(s) is between 0.5 and 10% by weight, or between 1 and 5% by weight, relative to the weight of the oil-in-water emulsion.

[0130] Waxes:

[0131] The oil-in-water emulsion according to the invention may optionally comprise at least one silicone wax, or one hydrocarbon wax, polar or apolar. The wax considered in the context of the present invention is of a generally a lipophilic compound which is solid at room temperature (25°C), with a reversible solid / liquid state change, having a melting point in particular greater than or equal to 30°C, more particularly greater than 45°C. Advantageously, the melting point is less than or equal to 90°C, more particularly less than or equal to 80°C, and preferably less than or equal to 70°C. The melting point of a solid fatty substance can be measured using a differential scanning calorimeter (DSC), for example the calorimeter sold under the name “DSC Q100” by the company TA Instruments with the “TA Universal Analysis” software.

[0132] The measurement protocol is as follows: A solid fat sample of approximately 5 mg is placed in a crucible "hermetic aluminum capsule". The sample is subjected to a first temperature rise from 20°C to 120°C, at a heating rate of 2°C / minute up to 80°C, then left at the isotherm of 100°C for 20 minutes, then cooled from 120°C to 0°C at a cooling rate of 2°C / minute, and finally subjected to a second temperature rise from 0°C to 20°C at a heating rate of 2°C / minute. The melting temperature value of the solid fat is the value of the top of the most endothermic peak of the melting curve observed, representing the variation of the difference in absorbed power as a function of temperature.

[0133] Polar hydrocarbon waxes

[0134] More particularly, the polar wax is chosen from hydrocarbon ester waxes, hydrocarbon alcohol waxes, silicone waxes, and mixtures thereof. The term "hydrocarbon wax" means a wax formed essentially, or even consisting of, carbon and hydrogen atoms, and optionally oxygen and nitrogen atoms, and not containing any silicon or fluorine atoms. It may contain alcohol, ester, ether, carboxylic acid, amine and / or amide groups. The term "ester wax" means, according to the invention, a wax comprising at least one ester function. Ester waxes may also be hydroxylated. The term "alcohol wax" means, according to the invention, a wax comprising at least one alcohol function, i.e. comprising at least one free hydroxyl (OH) group. The additional alcohol wax does not in particular comprise an ester function.By “silicone wax” is meant a wax comprising at least one silicon atom, and in particular comprising Si-O groups.

[0135] Ester waxes:

[0136] In particular, the following can be used as ester wax:

[0137] i) waxes of formula R1 -COO-R2 in which R1 and R2 represent linear, branched or cyclic aliphatic chains whose number of atoms varies from 10 to 50, which may contain a heteroatom, in particular oxygen, and whose melting point temperature varies from 30°C to 120°C, preferably from 30°C to 100°C. In particular, a C20-C40 alkyl (hydroxystearyloxy)stearate (the alkyl group comprising from 20 to 40 carbon atoms), alone or as a mixture, or a C20-C40 alkyl stearate, may be used as ester wax. Such waxes are sold under the names "Kester Wax K 82 P®", "Hydroxypolyester K 82 P®", "Kester Wax K 80 P®", or "KESTER WAX K82H" by the company KOSTER KEUNEN. Mixtures of C14-C18 carboxylic acid esters and alcohols can also be used, such as the products "Cetyl Ester Wax 814" from the company KOSTER KEUNEN, "SP Crodamol MS MBAL", "Crodamol MS PA" from the company CRODA, "Miraceti" from the company LASERSON.It is also possible to use a glycol and butylene glycol montanate (octacosanoate) such as LICOWAX KPS FLAKES wax (INCI name: glycol montanate) marketed by Clariant.

[0138] ii) di-(trimethylol-1,1,1-propane) tetrastearate, sold under the name Hest 2T4S® by the company HETERENE.

[0139] iii) diester waxes of a dicarboxylic acid of general formula R3-(-OCO-R4-COO-R5), in which R3 and R5 are identical or different, preferably identical and represent a C4-C30 alkyl group (alkyl group comprising from 4 to 30 carbon atoms) and R4 represents a linear or branched C4-C30 aliphatic group (alkyl group comprising from 4 to 30 carbon atoms) and which may or may not contain one or more unsaturations. Preferably, the C4-C30 aliphatic group is linear and unsaturated.

[0140] (iv) waxes obtained by catalytic hydrogenation of animal or vegetable oils having in particular linear or branched fatty chains, in C8-C32, for example such as hydrogenated jojoba oil, hydrogenated sunflower oil, hydrogenated castor oil, hydrogenated coconut oil, as well as waxes obtained by hydrogenation of castor oil esterified with cetyl alcohol, such as those sold under the names Phytowax ricin 16L64® and 22L73® by the company SOPHIM. Such waxes are described in application FR-A-2792190. As waxes obtained by hydrogenation of olive oil esterified with stearyl alcohol, mention may be made of those sold under the name “PHYTOWAX Olive 18 L 57”.

[0141] (v) waxes of animal or vegetable origin, such as beeswax, synthetic beeswax, carnauba wax, candelilla wax, lanolin wax, rice bran wax, ouricury wax, alfa wax, berry wax, shellac wax, cork fiber wax, sugar cane wax, Japan wax, sumac wax, montan wax, orange and lemon waxes, laurel wax, hydrogenated jojoba wax, sunflower wax, in particular refined.

[0142] vi) Mention may also be made of hydrocarbon waxes, polyoxyalkylenated or polyglycerolated, natural or synthetic, of animal or vegetable origin; the number of oxyalkylenated units (in C2-C4) may vary from 2 to 100, the number of glycerolated units may vary from 1 to 20. Examples include polyoxyethylenated beeswax, such as PEG-6 beeswax, PEG-8 beeswax; polyoxyethylenated carnauba waxes, such as PEG-12 carnauba; lanolin waxes, hydrogenated or not, polyoxyethenate or polyoxypropylenate, such as PEG-30 lanolin, PEG-75 lanolin; PPG-5 lanolin wax glyceride; polyglycerol beeswax, including polyglyceryl-3 Beewax, Acacia Decurrens / Jojoba / Sunflower Seed Wax / Polyglyceryl-3 Esters blend, polyglycerol vegetable waxes such as mimosa, jojoba, sunflower wax, and blends thereof (Acacia Decurrens / Jojoba / Sunflower Seed Wax Polyglyceryl-3 Esters.

[0143] vii) Waxes corresponding to partial or total, preferably total, esters of a saturated, optionally hydroxylated, C16-C30 carboxylic acid with glycerol. By total esters, it is meant that all the hydroxyl functions of the glycerol are esterified. By way of example, mention may be made of trihydroxystearin (or glyceryl trihydroxystearate), tristearin (or glyceryl tristearate), tribehenin (or glyceryl tribehenate), alone or in a mixture. Among suitable compounds, mention may be made of the triesters of glycerol and 12- hydroxystearic acid, or hydrogenated castor oil, such as Thixcin R, Thixcin E, marketed by Elementis Specialties.

[0144] (viii) as well as their mixtures.

[0145] Alcohol waxes

[0146] As alcohol wax, mention may be made of alcohols, preferably linear, preferably saturated, comprising from 16 to 60 carbon atoms, the melting point of which is between 25°C and 90°C. As examples of alcohol wax, mention may be made of stearic alcohol, cetyl alcohol, myristyl alcohol, palmitic alcohol, behenic alcohol, erucic alcohol, arachidyl alcohol, or mixtures thereof.

[0147] Non-polar hydrocarbon waxes

[0148] The oil-in-water emulsion may optionally comprise at least one additional wax chosen from apolar hydrocarbon waxes. For the purposes of the present invention, the term "apolar hydrocarbon wax" means a wax comprising only carbon or hydrogen atoms in its structure. In other words, such a wax is free of other atoms, in particular heteroatoms such as, for example, nitrogen, oxygen, silicon. As illustrations of the apolar waxes suitable for the invention, mention may in particular be made of hydrocarbon waxes such as microcrystalline waxes, paraffin waxes, ozokerite, polymethylene waxes, polyethylene waxes, waxes obtained by Fischer-Tropsch synthesis, microwaxes, in particular polyethylene.

[0149] Silicone waxes

[0150] As silicone wax, mention may be made, for example, of mixtures comprising a compound of the C30-45 Alkyldimethylsilyl Polypropylsilsesquioxane type (INCI name), for example the product Dow Corning SW-8005 C30 Resin Wax marketed by the company Dow Corning. Mention may also be made of mixtures comprising a compound of the C30-45 Alkyl Methicone type (INCI name), such as for example the product Dow Corning® AMS-C30 Cosmetic Wax. Mention may also be made of silicone beeswax. The oil-in-water emulsion according to the invention may comprise a content of wax(es), preferably polar, preferably hydrocarbon, of between 0.5 and 10% by weight, or from 0.5 to 6% by weight, or from 1 to 4% by weight, relative to the weight of the composition.

[0151] The emulsion according to the application can be an O / W emulsion with a very high oil content. 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 in 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.

[0152] Rheology agents (or hydrophilic thickeners)

[0153] The emulsion according to the application may further comprise a rheology agent, such as in particular an aqueous phase thickening agent, a gelling agent or a suspending agent. The rheology agent may be chosen from hydrophilic thickeners such as 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; microcrystalline cellulose; starch and its derivatives such as in particular starches modified by hydrophilic or ionic groups, in particular acetylated, carboxymethylated, or hydroxypropylated; synthetic polymers such as polyacrylic acids or carbomers.

[0154] Preferably, the emulsion according to the application comprises a rheology agent chosen from natural polysaccharides derived from plants or fermentation, optionally modified, used at a content ranging from 0.1% to 1% by weight of the total emulsion.

[0155] Preferably the gum of plant or microbial origin is a non-ionic polysaccharide. Gums derived from fermentation such as xanthans, gellans, mannans and scleroglucans are preferred, and in particular xanthans and scleroglucans, and more particularly xanthans. Such xanthan gums generally have a molecular weight of between 1,000 000 and 50,000,000 Da. Possible commercial products include, for example, the product Xanthan Gum FNCS-PC from the company: Jungbunzlauer International AG, the product Keltrol® CG-T from the company CP Kelco, the product Cosphaderm® X 17 from the company Cosphatec, the product Kahlgum 6673 FEE - Xanthan Gum from the company KahIWax, the products Rhodicare® S and Rhodicare® XC from the company Solvay and the product VANZAN® NF-C from the company Vanderbilt Minerals.

[0156] As cellulose derivative, modified celluloses may be used, in particular methylcelluloses, hydroxyalkylcelluloses, ethylhydroxyethylcelluloses, methylethylcelluloses, carboxymethylcelluloses, hydroxypropylcelluloses, hydroxypropylmethylcelluloses; carboxymethylcelluloses and hydroxyethylcelluloses being preferred, hydroxyethylcelluloses being the most preferred. In particular, the following commercial products may be mentioned: Natrosol™ 250 HHR PC from Ashland Specialty Chemical; Espesante CH from Chemir; Tylose® H 15 YG4 from SE Tylose and Cellosize™ HEC QP 40 from DowDuPont (Dow).

[0157] According to one embodiment, the rheology agent is chosen from xanthan, guar, carob or tara gums, or hydroxyethylated celluloses, microcrystalline celluloses, or mixtures thereof. According to a very preferred embodiment, the rheology agent is xanthan gum.

[0158] Brookfield Viscosity:

[0159] Brookfield viscosity measurement is performed at 20°C using a Brookfield DV-ll+Pro viscometer equipped with an appropriately chosen SP1, SP2 or SP3 spindle, rotated at a speed of 20 rotations per minute in contact with the sample produced. The emulsion's resistance to this rotational movement is recorded for one minute and converted into mPascal. second, noted mPa.s. Under these measurement conditions, the spindle develops very low shear, of the order of 0.1 s -1 . For each emulsion sample, the viscosity is measured three times and the arithmetic mean of the three values ​​is taken. The choice of the spindle adapted to the viscosity to be measured is made according to the following ranges:

[0160] - when the viscosity is less than or equal to 500 mPa.s, the chosen spindle is spindle SP1,

[0161] - when the viscosity is between 500 mPa.s and 5000 mPa.s, the chosen spindle is the SP2 spindle,

[0162] - when the viscosity is between 5,000 mPa.s and 10,000 mPa.s, the chosen spindle is the SP3 spindle.

[0163] In case of viscosity above 5000 mPa.s, the following pins could be chosen: SP4 when the viscosity is between 10,000 mPa.s and 20,000 mPa.s and SP5 when the viscosity is between 20,000 and 50,000 mPa.s.

[0164] According to one embodiment, the emulsion according to the present application preferably has a Brookfield viscosity of less than 3,000 mPas at 20°C, or less than or equal to 2,800 mPas at 20°C, or less than or equal to 2,600 mPa.s, or less than or equal to 2,250 mPa.s, or less than or equal to 2,000 mPa.s, or less than or equal to 1,750 mPa.s, or less than or equal to 1,500 mPa.s, or less than or equal to 1,000 mPa.s, or less than or equal to 500 mPa.s, or less than or equal to 100 mPa.s.

[0165] According to an embodiment complementary to the previous one, said emulsion has a Brookfield viscosity greater than or equal to 10 mPa.s, or greater than or equal to 20 mPa.s, or greater than or equal to 30 mPa.s, or greater than or equal to 50 mPa.s, or greater than or equal to 60 mPa.s, or greater than or equal to 70 mPa.s, or greater than or equal to 80 mPa.s, or greater than or equal to 90 mPa.s

[0166] Characteristic size of the dispersed phase

[0167] The emulsions according to the application 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 that 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.

[0168] Emulsification process

[0169] An object of the present application is a process for emulsifying an oily phase in an aqueous phase to obtain an oil-in-water emulsion having a Brookfield viscosity at 20°C and 20 rpm for 1 min with the SP5 spindle, less than 3000 mPa.s, preferably less than 2000 mPa.s, more preferably less than 1000 mPa.s, and most preferably less than 500 mPa.s, said process comprising the steps of: a) providing an aqueous phase, b) solubilizing an emulsifying system consisting of at least one emulsifier of starchy origin and at least one cyclodextrin in the aqueous phase to obtain a homogeneous aqueous phase, c) emulsifying an oily phase in the aqueous phase by means of stirring at a rotation speed less than or equal to 7500 rpm, preferably ranging from 1000 to 7500 rpm, preferably from 2000 to 5000 rpm, more preferably 2500 to 4000 rpm.

[0170] The stirring speeds selected for the emulsification process according to the invention make it possible to develop a shear considered moderate to low in the field of emulsification, where values ​​of 10,000 rpm or even 20,000 rpm are more common.

[0171] Preferably, this emulsion has a Brookfield viscosity at 20°C and 20 rpm for 1 min with the SP1 spindle, greater than or equal to 10 mPa.s, or greater than or equal to 20 mPa.s, or greater than or equal to 30 mPa.s, or greater than or equal to 50 mPa.s, or greater than or equal to 60 mPa.s, or greater than or equal to 70 mPa.s, or greater than or equal to 80 mPa.s, or greater than or equal to 90 mPa.s.

[0172] The emulsification process may comprise an additional step b') consisting of solubilizing a low molecular weight emulsifying surfactant at a content of less than or equal to 1% by gross weight of emulsion, preferably less than or equal to 0.5%, more preferably less than or equal to 0.1%. This step is preferably carried out before step c).

[0173] According to one embodiment, step b) is carried out with a starchy emulsifier or emulsifier of starchy origin having a solubility in water at 22°C according to test A greater than or equal to greater than or equal to 50%, or greater than or equal to 75%, or greater than or equal to 85%, or greater than or equal to 95%, or greater than or equal to 98%, or greater than or equal to 99%, or equal to 100%.

[0174] Preferably, the emulsifying system of step b) can also provide a quantity of cyclodextrin representing from 2.5 to 6% by weight, preferably from 3 to 5% by weight, and more preferably from 3.5 to 4.5% by weight, or from 2.5 to 4% by weight, relative to the total weight of emulsion.

[0175] Preferably, the emulsifying system of step b) can also provide a quantity of starchy emulsifier or emulsifier of starchy origin representing from 1 to 7% by weight, preferably from 1.5 to 6% by weight, more preferably from 2 to 5% by weight, and most preferably from 2.5 to 4.5%, or from 1.0 to 2.5% by weight, relative to the total weight of emulsion.

[0176] Preferably, the emulsifying system consisting of at least one emulsifier of starchy origin and at least one cyclodextrin, the emulsification process is the only emulsifier introduced into the process.

[0177] Preferably, the process temperature is between 10°C and 60°C, preferably between 15°C and 40°C, and more preferably between 18°C ​​and 30°C.

[0178] The solubilization of the emulsifying system is almost complete in the aqueous phase, i.e. at 22°C at least 50%, better still at least 75%, and even better still, greater than or equal to 85%. Ideally, at least 95% by weight of said emulsifying system is solubilized in the aqueous phase, preferably at least 98% by weight, more preferably at least 99% by weight, and most preferably 100% by weight. According to one embodiment, all the solid particles of emulsifying system are solubilized in the aqueous phase. The aqueous phase therefore does not contain solid particles of emulsifying system, or derived from said emulsifying system.

[0179] An advantage of the emulsification process which is the subject of the present application is that it can be carried out at moderate temperatures, for example below 60°C, or low temperatures, for example below 30°C. This process makes it possible to avoid using high temperatures, in particular to avoid using temperatures above 60°C.

[0180] Another advantage of the emulsification process that is the subject of the present application is that the emulsification can be carried out with stirring inducing moderate to low shear, thus avoiding heating of the emulsion. Compared to emulsifications made at high shear, the total energy consumption of the emulsification process is lower, and in particular the amount of energy to be dissipated in the medium to be emulsified is reduced, which is favorable to maintaining the integrity of the polymeric structure of the emulsifier of starchy origin, and to the non-degradation of the other heat-sensitive constituents introduced into the emulsion. Indeed, the polymeric chains of anhydroglucose like those of other molecules are likely to be broken under the effect of high shear, in particular when it is combined with a high temperature. Such breaks lead to the degradation of the ability of the starch-based emulsifier to emulsify oil in water.To maximize the emulsifying power of the emulsifier of starch origin, it is imperative that the latter retains a sufficient polymeric structure, i.e. preferably a weight-average molecular mass, measured by HPSEC-MALLS, ranging from 10 to 2,000 kDa, or from 20 to 1,500 kDa, or from 30 to 1,000 kDa, or from 40 to 800 kDa, or from 45 to 700 kDa.

[0181] The process which is the subject of the present application effectively makes it possible to preserve the complexity of the starch polymer chains, and thus to maintain its maximum capacity to emulsify an oily phase in an aqueous phase.

[0182] The oil-in-water emulsions and cosmetic compositions which are the subject of the present application are advantageously prepared by the moderate to low shear emulsification process, optionally at moderate to low temperature, as defined above. Examples

[0183] Example 1: Preparation of sunflower oil emulsions according to the invention

[0184] Oil-in-water emulsions were prepared from sunflower oil and by combining a native beta-cyclodextrin “Beauté by Roquette® CD 102” and an emulsifier of starchy origin chosen from two water-soluble octenyl succinate starches Cleargum® CO 01 and Cleargum® CO 03, and an octenyl dextrin water-soluble succinate Cleargum® CO A1, in mass contents ranging from 2.5 to 4% by weight of emulsion for beta-cyclodextrin and from 1 to 4% by weight of emulsion for the starchy emulsifier, and this for a mass proportion of oil of 30% by weight of emulsion, according to the compositions in table 1.

[0185] [Table 11

[0186] To prepare each emulsion, the aqueous phase was prepared by dispersing the required amounts of cyclodextrin and emulsifier of starch origin in the total required mass of water at 40-45°C while stirring with a deflocculating blade at 1000 rpm for 10 min. Then the mass of oil previously heated to 40-45°C was added to the aqueous phase while stirring with a deflocculating blade at 3000-3300 rpm, which corresponds to low shear according to the present application, for 15 minutes. It was then allowed to cool to 20°C and then the pH was adjusted to 6. Finally, the emulsion was allowed to stand at 20°C for 48 hours.

[0187] 48 hours after the preparation of the emulsion, the Brookfield viscosities were measured at 20°C with the SP5 spindle at 20 rpm for 1 minute, expressed in mPa.s, after the 48-hour rest period. The results are shown in Table 2 for the combination of a beta-cyclodextrin and Cleargum CO 03, in Table 3 for the combination of beta-cyclodextrin and Cleargum CO 01, and in Table 4 for the combination of beta-cyclodextrin and Cleargum CO A1.

[0188] [Table 21

[0189] [Table 31

[0190] [Table 41

[0191] It was thus found that the emulsions prepared with the combination of a cyclodextrin and an emulsifier of starchy origin chosen from Cleargum® CO 03, CO 01 and CO A1, actually have a viscosity of less than 3000 mPa.s, and that the viscosity of said emulsions seems to be able to be adjusted by varying the respective quantities of cyclodextrin and emulsifier of starchy origin. In addition, it was found that the viscosity of the emulsions thus prepared is lower than that of emulsions formed solely with a cyclodextrin (and therefore without emulsifier of starchy origin). Finally, it was also found that the emulsions prepared with at least 1% by weight of starch emulsifier and at least 2.5% by weight of cyclodextrin, were stable after 48 hours and up to 6 months after their preparation.

[0192] Regarding the possibility of making emulsions without beta-cyclodextrin, only with one of the octenyl succinate modified starches of the present example, we tried to prepare an emulsion No. 15 using 65.6% by weight of water, 4% by weight of Cleargum CO 03 starch and 30% by weight of sunflower oil. A non-homogeneous mixture, initially resembling an emulsion with a viscosity of 950 mPa.s, but quickly showing marbling, then demixing of the phases in less than 24 hours, was obtained. It was therefore not possible to form an emulsion in the absence of beta-cyclodextrin.

[0193] Example 2: Preparation of sunflower oil emulsions outside the invention

[0194] Oil-in-water emulsions were prepared from sunflower oil and by combining a native beta-cyclodextrin “Beauté by Roquette® CD 102” and an octenyl succinate modified granular starch, Beauté by Roquette® ST 012, at a content of 4% by weight of emulsion for the beta-cyclodextrin and 1.5 to 4% by weight of emulsion for the octenyl succinate granular starch, for a mass proportion of oil of 30% by weight of emulsion, according to the compositions in Table 5.

[0195] To prepare each emulsion, the aqueous phase was prepared by dispersing the required amounts of cyclodextrin and emulsifier of starch origin in the total required mass of water at 40-45°C while stirring with a deflocculating blade at 1000 rpm for 10 min. Then the mass of oil previously heated to 40-45°C was added to the aqueous phase while stirring with a deflocculating blade at 3000-3300 rpm, which corresponds to low shear according to the present application, for 15 minutes. It was then allowed to cool to 20°C and then the pH was adjusted to 6. Finally, the emulsion was allowed to stand at 20°C for 48 hours.

[0196] 48 hours after the preparation of the emulsion, the Brookfield viscosities were measured at 20°C with the SP5 spindle at 20 rpm for 1 minute, expressed in mPa.s, after the 48-hour rest period. The results are shown in Table 5.

[0197] [Table 51

[0198] Emulsions prepared with granular starch octenyl succinate and beta-cyclodextrin exhibited viscosities 2500 to 3000 mPa.s higher than the viscosities achieved with the water-soluble starch octenyl succinates of Example 1. Furthermore, these emulsions proved unstable within 48 hours of their preparation: marbling appeared, a sign of phase demixing, and observation under an optical microscope revealed non-spherical oil particles, indicative of coalescence.

Claims

Claims

1. An oil-in-water emulsion comprising: - an oily phase dispersed in an aqueous phase, - an emulsifying system consisting of at least one cyclodextrin and at least one starchy and / or starchy-origin emulsifier, said emulsion having a Brookfield viscosity, at 20°C at 20 rpm for 1 min with the SP5 spindle, of less than 3000 mPa.s, preferably less than or equal to 2800 mPa.s, preferably less than or equal to 2600 mPa.s, and in which the starchy and / or starchy-origin emulsifier has a solubility in water at 22°C according to test A of greater than or equal to 50%, or greater than or equal to 75%, or greater than or equal to 85%, or greater than or equal to 95%, or greater than or equal to 98%, or greater than or equal to 99%, or equal to 100%.

2. Oil-in-water emulsion according to claim 1, in which the mass content of said at least one cyclodextrin relative to the total weight of the emulsion is within a range of 2.5 to 6% by weight, 3 to 5% by weight, and most preferably 3.5 to 4.5% by weight of emulsion, or 2.5 to 4% by weight.

3. Oil-in-water emulsion according to one of claims 1 or 2, in which the mass content of said at least one starchy and / or starchy emulsifier relative to the total weight of the emulsion is within a range from 1 to 7% by weight, from 1.5 to 6% by weight, from 2 to 5% by weight, and most preferably from 2.5 to 4.5% by weight of emulsion, or from 1.0 to 2.5% by weight.

4. An oil-in-water emulsion according to any one of the preceding claims, wherein said emulsion has a Brookfield viscosity, at 20°C at 20 rpm for 1 min with the SP1 spindle, greater than 10 mPa.s, preferably greater than or equal to 20 mPa.s, preferably greater than or equal to 30 mPa.s, preferably greater than or equal to 50 mPa.s.

5. Oil-in-water emulsion according to any one of the preceding claims, in which the emulsion is biodegradable to more than 90%, in particular to more than 93% according to OECD standard 301 F.

6. Oil-in-water emulsion according to the preceding claim, comprising less than 1% by weight, preferably less than 0.5% by weight, preferably 0% by weight, of surfactant having a molecular weight or mass average molecular weight, less than or equal to 250 Da, preferably less than or equal to 500 Da, preferably less than or equal to 750 Da, preferably less than or equal to 1 kDa, preferably less than or equal to 10 kDa.

7. Oil-in-water emulsion according to the preceding claim, in which said at least one cyclodextrin is chosen from native cyclodextrins and modified cyclodextrins, preferentially from native or modified alpha-cyclodextrin, gamma-cyclodextrin or beta-cyclodextrin, more preferentially from native alpha-cyclodextrin, gamma-cyclodextrin or beta-cyclodextrin, and most preferentially is native beta-cyclodextrin.

8. Oil-in-water emulsion according to the preceding claim, in which the starchy or starch-derived emulsifier is a starch, a dextrin or a maltodextrin.

9. Oil-in-water emulsion according to any one of the preceding claims, in which said at least one starchy and / or starchy emulsifier comprises at least one amphiphilic group, preferably at least one alkenyl succinate group, preferably at least one alkali or alkaline earth metal octenyl succinate group, most preferably at least one sodium or calcium octenyl succinate group, and even more preferably a sodium octenyl succinate group.

10. An oil-in-water emulsion according to any preceding claim, wherein the starch is a pregelatinized starch, gelatinized, atomized, acid-hydrolyzed or enzymatically hydrolyzed, or a starch modified by a combination of these modifications, preferably the starch is a hydrolyzed and pregelatinized starch.

11. An oil-in-water emulsion according to any preceding claim, wherein the starchy or starch-derived emulsifier is selected from pregelatinized starch octenyl succinate, gelatinized starch octenyl succinate, hydrolyzed starch octenyl succinate, hydrolyzed and pregelatinized starch octenyl succinate, dextrin octenyl succinate, maltodextrin octenyl succinate, and mixtures thereof.

12. An oil-in-water emulsion according to any preceding claim, wherein the starchy or starch-derived emulsifier is selected from pregelatinized starch octenyl succinate, gelatinized starch octenyl succinate, hydrolyzed starch octenyl succinate, hydrolyzed and pregelatinized starch octenyl succinate, and mixtures thereof.

13. Oil-in-water emulsion according to any one of the preceding claims, in which the ratio of the mass of starchy or starchy emulsifier to the mass of cyclodextrin is within a range from 0.2 to 2, preferably from 0.3 to 1.6, preferably from 0.4 to 1.2, preferably from 0.5 to 1, preferably from 0.55 to 0.9, and most preferably from 0.60 to 0.

80.

14. Oil-in-water emulsion according to one of the preceding claims, characterized in that the mass content of said emulsifying system in said emulsion is greater than or equal to 3.5% by weight, preferably 4% by weight, preferably 4.5% by weight, preferably 5% by weight.

15. An oil-in-water emulsion according to any preceding claim, wherein the emulsifying system is the sole and unique emulsifier present in the emulsion.

16. An oil-in-water emulsion according to any preceding claim, containing an amount of native granular starch or modified, preferably amphiphilic modified granular starch, more preferably octenyl succinate granular starch, less than or equal to 5% by weight, preferably less than or equal to 2% by weight, more preferably less than or equal to 1% by weight, even more preferably less than or equal to 0.5% by weight, and most preferably equal to 0% by weight, relative to the total weight of the emulsion.

17. A process for emulsifying an oily phase in an aqueous phase to obtain an oil-in-water emulsion having a Brookfield viscosity at 20°C and 20 rpm for 1 min with the SP5 spindle, less than 3000 mPa.s, preferably less than 2000 mPa.s, more preferably less than 1000 mPa.s, and most preferably less than 500 mPa.s, said process comprising the steps of: a) providing an aqueous phase, b) solubilizing an emulsifying system consisting of at least one starchy or starchy emulsifier and at least one cyclodextrin in the aqueous phase to obtain a homogeneous aqueous phase, c) emulsifying an oily phase in the aqueous phase by means of stirring at a rotation speed less than or equal to 7500 rpm.

18. Oil-in-water emulsion, characterized in that it is obtained by the emulsification process according to claim 17.

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