WO2018077986A1

WO2018077986A1 - Double emulsions with double coacervate

Info

Publication number: WO2018077986A1
Application number: PCT/EP2017/077372
Authority: WO
Inventors: Mathieu Goutayer; Yan Eric PAFUMI; Amélie PUJOL
Original assignee: Capsum
Priority date: 2016-10-26
Filing date: 2017-10-25
Publication date: 2018-05-03
Also published as: FR3057767A1; FR3057767B1

Abstract

The invention relates to a water-in-oil-in-water emulsion, comprising a continuous external aqueous phase and a water-in-oil emulsion in the form of drops (G1), each drop (G1) comprising a continuous fatty phase and at least one drop (G2) comprising an internal aqueous phase, the exterior of said drops (G1) being formed from at least one anionic polymer (PA1) and at least one cationic polymer (PC), and the exterior of said drops (G2) being formed from at least one anionic polymer (PA2), which is the same as or different from (PA1), and at least one cationic polymer (PC).

Description

DOUBLE EMULSIONS WITH DOUBLE COACERVAT

The subject of the present invention is dual water-in-oil-in-water emulsions whose internal fatty and aqueous phases are in the form of drops. It also relates to their preparation process and their use in cosmetic compositions.

Today, interest in the encapsulation of hydrophilic compounds continues to grow. Indeed, encapsulation technologies concern a wide variety of industrial sectors such as medicine, pharmacy, food or cosmetics. Encapsulating a hydrophilic compound, such as a cosmetic active ingredient, consists in isolating it from the external medium. This strategy is particularly necessary when this compound is incompatible with other elements of the aqueous phase. Several methods have been developed to better adapt to different applications such as spray-drying or the coacervation method.

However, the development of new systems for encapsulating hydrophilic compounds satisfactorily remains a constant goal.

The present invention aims to provide a double emulsion, especially macroscopic, for encapsulating hydrophilic compounds.

More particularly, the present invention aims to provide a dual emulsion, especially macroscopic, with encapsulating properties of satisfactory hydrophilic compounds combined with a visual and / or texture novel and particularly attractive to the consumer.

Thus, the present invention relates to a water-in-oil-in-water emulsion, comprising an external continuous aqueous phase and, as a dispersed phase, a water-in-oil emulsion in the form of drops (G1), each drop ( G1) comprising a continuous fatty phase and at least one, preferably a single, drop (G2) comprising an internal aqueous phase,

said drops (G1) comprising a bark formed of at least one anionic polymer (PA1) and at least one cationic polymer (PC), and

said drops (G2) comprising a bark formed of at least one anionic polymer (PA2), identical to or different from (PA1), and at least one cationic polymer (PC). The invention thus relates to dual water-in-oil-in-water emulsions with double coacervation. Preferably, in an emulsion according to the invention, the drops (G1) and (G2) are macroscopic, that is to say visible to the naked eye.

In the context of the present invention, the aforementioned emulsions may also be referred to as "dispersions".

The emulsions according to the invention comprise:

an internal aqueous phase,

an intermediate fatty phase, and

an external aqueous phase.

These emulsions comprise, in the external aqueous phase, drops (G1) of oily phase comprising a bark formed by coacervation, each drop (G1) of fatty phase containing at least one drop (G2) of internal aqueous phase, this drop (G2 ) of internal aqueous phase also comprising a bark formed by coacervation.

An emulsion according to the invention is particularly advantageous, on the one hand, in that it ensures a particularly satisfactory encapsulation of hydrophilic compounds thanks to the drops (G2), but also of lipophilic compounds thanks to the drops (G1), and, d On the other hand, it is endowed with a unique visual and texture in the field of double emulsions which, for obvious reasons, responds to a continuous demand from consumers for this purpose.

An emulsion according to the invention is also particularly advantageous in terms of kinetic stability, since the drops (G1) or (G2) remain intact over a time scale greater than 1 week, or even greater than 1 month, and even greater than 3 months, at room temperature, for example T = 25 ° C ± 2 ° C, and at ambient pressure, for example 1013 mbar.

As such, it was not obvious that double emulsions are stable at room temperature, for example T = 25 ° C ± 2 ° C, and at ambient pressure, for example 1013 mbar.

This interesting property in terms of kinetic stability is all the more unexpected as the bark of the drops (G1) and (G2), described in detail below, is very fine. Thus, no resistance attached to the breaking of the bark is felt by the user at the time of application to a keratinous material, and no residual deposit of said bark is also found. This is called evanescent bark. The drops (G1) and (G2), by the nature and properties of their barks, therefore differ from solid capsules, that is to say capsules with a solid membrane, such as for example those described in WO 2010/063937.

Moreover, the microfluidic process used to manufacture an emulsion according to the invention makes it possible to form macroscopic and monodisperse drops (G1) and (G2). In addition, the microfluidic process allows a perfect control of the contents of each phase implemented, and therefore the concentrations of the encapsulated actives.

According to the invention, the pH of an emulsion is typically between 4.0 and 8.0, in particular between 5.0 and 7.0.

The invention also relates to the use of an emulsion according to the invention, for the preparation of a composition, in particular a cosmetic composition. An emulsion according to the invention, or even a composition comprising it, can also be dedicated to the field of medicine, pharmacy or (agro) food.

Thus, the invention also relates to a composition, in particular a cosmetic composition, comprising at least one emulsion according to the invention and, in particular, a physiologically acceptable medium.

Viscosity

The viscosity of the emulsions according to the invention can vary significantly, which makes it possible to obtain varied textures.

According to one embodiment, an emulsion according to the invention has a viscosity of from 1 mPa.s to 500,000 mPa.s, preferably from 10 mPa.s to 300,000 mPa.s, better still from 400 mPa.s to 100 mPa.s. 000 mPa.s, and more particularly from 1000 mPa.s to 30,000 mPa.s, as measured at 25 ° C.

The viscosity is measured at room temperature, for example T = 25 ° C ± 2 ° C, and at ambient pressure, for example 1013 mbar, by the following method.

A Brookfield type viscometer, typically a Brookfield RVDV-E digital viscometer (spring torque of 7187.0 dyne-cm), is used which is a rotational speed-controlled rotational viscometer (designated by the English term). "Spindle"). A speed is imposed on the mobile in rotation and the measurement of the torque exerted on the mobile makes it possible to determine the viscosity knowing the geometry / shape parameters of the mobile used.

For example, a mobile of size No. 04 (Brookfield reference: RV4) is used. The shear rate corresponding to the measurement of the viscosity is defined by the mobile used and the speed of rotation thereof. The viscosity measurement is carried out for 1 minute at room temperature (T = 25 ° C. ± 2 ° C.). About 150 g of solution are placed in a beaker of 250 ml volume, having a diameter of about 7 cm so that the height of the volume occupied by the 150 g of solution is sufficient to reach the dipstick marked on the surface. mobile. Then, the viscometer is started at a speed of 10 rpm and the value displayed on the screen is expected to be stable. This measurement gives the viscosity of the tested fluid, as mentioned in the context of the present invention.

External continuous aqueous phase

As indicated above, the emulsions according to the invention comprise an external continuous aqueous phase, preferably in the form of a gel, in particular a gel having a viscosity adapted to suspend the drops (G1) and thus contribute to the attractive visual and novelty of an emulsion according to the invention.

According to one embodiment, this aqueous phase has a viscosity of between 1 mPa.s and 500,000 mPa.s, preferably between 10 mPa.s and 300,000 mPa.s, better still between 400 mPa.s and 100,000 mPa. s, and more particularly between 1000 mPa.s and 30,000 mPa.s, as measured at 25 ° C.

This viscosity is measured according to the method described above.

The continuous aqueous continuous phase of the emulsions comprises at least water.

In addition to distilled or deionized water, water suitable for the invention may also be natural spring water or floral water.

According to one embodiment, the weight percentage of water of the external aqueous continuous phase is at least 30%, preferably at least 40%, in particular at least 50%, and better still at least 60%, especially between 70% and 98%, and preferably between 55% and 95%, in particular between 75% and 85%, relative to the total mass of said external aqueous phase.

The continuous aqueous continuous phase of the emulsion according to the invention may further comprise at least one base. It may comprise a single base or a mixture of several different bases. When the external continuous aqueous phase of an emulsion according to the invention comprises at least one pH-sensitive gelling agent, the presence of at least one base in said aqueous continuous phase notably contributes to raising the viscosity of the latter.

According to one embodiment, the base present in the aqueous phase is a mineral base. According to one embodiment, the mineral base is selected from the group consisting of alkali metal hydroxides and alkaline earth metal hydroxides.

Preferably, the mineral base is an alkali metal hydroxide, and especially NaOH.

According to another embodiment, the base present in the external aqueous phase is an organic base. Among the organic bases, mention may be made, for example, of ammonia, pyridine, triethanolamine, aminomethylpropanol, or else triethylamine.

An emulsion according to the invention may comprise from 0.01% to 10% by weight, preferably from 0.01% to 5% by weight, and preferably from 0.02% to 1% by weight of base, preferably from mineral base, and especially NaOH, relative to the total weight of said emulsion.

According to one embodiment, the emulsions according to the invention, or even the compositions comprising them, do not comprise a surfactant.

Drops (G1)

As indicated above, the double emulsions according to the invention comprise, as dispersed phase, a water-in-oil emulsion in the form of drops (G1).

A drop (G1) according to the invention is composed of a heart, also called inside of the drop, surrounded by a bark, which isolates the inside of the drop of the external aqueous phase of the emulsion.

According to one embodiment, the size of the drops (G1) is greater than 500 μηι, or even greater than 1,000 μηι, and better still lies between 500 μηι and 3,000 μηι, preferably between 1,000 μηι and 2,000 μηι, in in particular between 800 μηι and 1,500 μπι.

In the context of the present invention, the term "size" refers to the diameter, in particular the mean diameter, of the drops.

According to one embodiment, an emulsion according to the invention is obtained by a microfluidic process as defined below. As a result, the drops (G1) have a uniform size distribution. Preferably, the fatty phase of the emulsions of the invention consists of a population of monodisperse drops (G1), especially such that they have a mean diameter D of 500 μηι to 3000 μηι and a coefficient of variation Cv lower at 10% or even less than 3%. In the context of the present description, the term "monodisperse drops" means that the population of drops of the dispersed phase according to the invention has a uniform size distribution. Monodispersed drops have good monodispersity. Conversely, drops with poor monodispersity are said to be "polydispersed".

According to a mode, the average diameter D of the drops is for example measured by analysis of a photograph of a batch consisting of N drops, by an image processing software (Image J). Typically, according to this method, the diameter is measured in pixels, then reported in μηι, depending on the size of the container containing the drops of the emulsion.

Preferably, the value of N is chosen greater than or equal to 30, so that this analysis reflects in a statistically significant manner the drop diameter distribution of said emulsion.

We measure the diameter Di of each drop, then we obtain the average diameter D _e n calculating the arithmetic mean of these values:

1 ^N

N tr

From these values D "one can also obtain the standard deviation σ of the diameters of the drops of the emulsion:

The standard deviation σ of an emulsion reflects the distribution of the diameters D, drops of the emulsion around the average diameter D.

Knowing the average diameter D _e t the standard deviation σ of an emulsion, it can be determined that 95.4% of the population of drops is found in the range of diameters [ζ) - 2σ; Ζ) + 2σ] and that 68.2% of the population is found in the interval ρ - σ; Σ ⁾ + σ]

To characterize the monodispersity of the emulsion according to this mode of the invention, the coefficient of variation can be calculated:

C =

v D

This parameter reflects the distribution of the diameters of the drops as a function of the average diameter thereof. The coefficient of variation Cv of the drop diameters (G1) according to this embodiment of the invention is less than 10%, preferably less than 5%, or even less than 3%.

In particular, the emulsions according to the invention comprise from 0.1% to 70%, preferably from 0.5% to 65%, in particular from 1% to 60%, better still from 3% to 50%, and more particularly from 5% to 20%, by weight of drops (G1) (ie formed of the continuous fat phase and the internal aqueous phase) relative to the total weight of said emulsion.

As indicated above, each drop (G1) comprises a fatty phase corresponding to the fatty phase of the emulsions according to the invention.

Fatty phase

According to one embodiment, the fatty phase of the drops (G1) comprises at least one oil. The fatty phase of the drops (G1) can therefore be designated as an oily phase.

Oils)

The drops (G1) according to the invention may comprise a single oil or a mixture of several oils. An emulsion according to the invention may therefore comprise at least one, at least two, at least three, at least four, at least five or more oil (s) as described (s) below .

The term "oil" means a fatty substance that is liquid at room temperature (25 ° C.).

As oils that can be used in the emulsion of the invention, mention may be made for example of:

hydrocarbon oils of plant origin, in particular as described below;

hydrocarbon oils of animal origin, such as perhydrosqualene and squalane;

esters and synthetic ethers, in particular of fatty acids, such as the oils of formulas F 1 COOF 2 and F 4 FF 4 in which R 1 represents the residue of a C ₈ to C ₂₉ fatty acid, and R ₂ represents a hydrocarbon chain, branched or unbranched, C ₃ to C ₃₀ , such as, for example, purcellin oil, isononyl isononanoate, isodecyl neopentanoate, isopropyl myristate, ethyl palmitate, 2-hexyl, octyl-2-dodecyl stearate, octyl-2-dodecyl erucate, isostearyl isostearate; hydroxylated esters such as isostearyl lactate, octyl hydroxystearate, octyldodecyl hydroxystearate, diisostearyl malate, triisocetyl citrate, heptanoates, octanoates, decanoates of fatty alcohols; the polyol esters, such as propylene glycol dioctanoate, neopentyl glycol diheptanoate and diethylene glycol diisononanoate; and pentaerythritol esters such as pentaerythrityl tetrahehenate (DUB PTB) or pentaerythrityl tetraisostearate (Prisorine 3631);

linear or branched hydrocarbons of mineral or synthetic origin, such as paraffin oils, volatile or not, and their derivatives, petroleum jelly, polydecenes, hydrogenated polyisobutene such as Parleam oil;

silicone oils, for example volatile or non-volatile polymethylsiloxanes (PDMSs) with a linear or cyclic silicone chain, which are liquid or pasty at room temperature, in particular cyclopolydimethylsiloxanes (cyclomethicones) such as cyclohexasiloxane and cyclopentasiloxane; polydimethylsiloxanes (or dimethicones) comprising alkyl, alkoxy or phenyl groups, during or at the end of the silicone chain, groups having from 2 to 24 carbon atoms; phenyl silicones such as phenyltrimethicones, phenyldimethicones, phenyltrimethylsiloxydiphenylsiloxanes, diphenyl-dimethicones, diphenylmethyldiphenyltrisiloxanes, 2-phenylethyltrimethylsiloxysilicates, and polymethylphenylsiloxanes;

fatty alcohols having from 8 to 26 carbon atoms, such as cetyl alcohol, stearyl alcohol and their mixture (cetylstearyl alcohol), or alternatively octyldodecanol;

partially fluorinated hydrocarbon oils and / or silicone oils such as those described in document JP-A-2-295912;

- and their mixtures.

According to a preferred embodiment, the oil is chosen from esters and synthetic ethers, preferably esters of formula R ₁ COOR ₂ , in which R 1 represents the residue of a C ₈ to C ₂₉ fatty acid, and R ₂ represents a hydrocarbon chain, branched or unbranched, C ₃ to C ₃₀ .

According to one embodiment, the oil is chosen from fatty alcohols having from 8 to 26 carbon atoms.

According to one embodiment, the oil is chosen from hydrocarbon-based oils having 8 to 16 carbon atoms, and in particular branched C ₈ -C ₁₆ alkanes (also known as isoparaffins or isoalkanes), such as isododecane (also called 2-méthylundécane) isodecane, isohexadecane and, for example, the oils sold under the trade names Isopar ^® or Permethyls® ^®. According to a preferred embodiment, the oil is chosen from the group consisting of isononyl isononanoate, dimethicone, isohexadecane, polydimethylsiloxane, octyldodecanol, isodecyl neopentanoate and mixtures thereof. .

According to another preferred embodiment, the fatty phase of the drops (G1) comprises an oil chosen from silicone oils. Preferably, the fatty phase of the drops (G1) does not include other oils other than silicone oils. Preferably, the oils present in the fatty phase of the drops (G1) are silicone oils.

According to a preferred embodiment, an emulsion according to the invention comprises at least 1% by weight of oil (s) relative to the total weight of said emulsion.

According to another embodiment, an emulsion according to the invention, in particular the fatty phase of the drops (G1), does not comprise polydimethylsiloxane (PDMS), and preferably does not comprise silicone oil.

According to another embodiment, an emulsion according to the invention does not comprise vegetable oil.

According to yet another embodiment, the fatty phase of the drops (G1) of an emulsion according to the invention comprises at least one hydrocarbon oil of plant origin. As vegetable oils, particular mention may be made of liquid triglycerides of C ₄ -C ₁₀ fatty acids, such as the triglycerides of heptanoic or octanoic acids or, for example, sunflower, corn, soybean, pumpkin and seed oils. grape, sesame, hazelnut, apricot, macadamia, arara, castor, avocado, triglycerides of caprylic / capric acids (INCI name: Caprylic / Capric Triglyceride) such as those marketed by the company Stearineries Dubois or those available under the trade names "Miglyol 810", "Miglyol 81 2" and "Miglyol 81 8" by the company Dynamit Nobel, jojoba oil, shea butter oil, and their mixture.

Preferably, the vegetable oil is chosen from those rich in polyunsaturated fatty acids. For the purposes of the present invention, the term "unsaturated fatty acid" means a fatty acid comprising at least one double bond. It is more particularly long chain fatty acids, that is to say can have more than 14 carbon atoms. The unsaturated fatty acids may be in acid form, or in salt form, for example their calcium salt, or in the form of derivatives, especially fatty acid ester (s). Preferably, the vegetable oil is chosen from oils rich in long chain fatty acids, that is to say able to have more than 14 carbon atoms, and better unsaturated fatty acids having from 1 to 22 carbon atoms. carbon, especially ω-3 and ω-6 fatty acids. Thus, advantageously, the vegetable oils are chosen from evening primrose, borage, blackcurrant seed, hemp, walnut, soybean, sunflower, wheat germ, fenugreek, rosebush and musk rosebush oils. echium, argan, baobab, rice bran, sesame, almond, hazelnut, chia, flax, olive, avocado, safflower, coriander, rapeseed (in particular Brassica naptus ), and their mixtures.

Preferably, the vegetable oil is chosen from matt and non-glossy oils. In particular, mention may be made of Moringa oil.

According to yet another embodiment, the fatty phase of the drops (G1) of an emulsion according to the invention comprises at least one non-volatile hydrocarbon oil (or H 1 oil) containing more than 90%, preferably more than 95% of fatty acids of chain length greater than or equal to 18 carbon atoms, preferably greater than or equal to 20 carbon atoms.

Preferably more than 90% and preferably more than 95%, of the fatty acids of the non-volatile hydrocarbon oil has a chain length between C ₈ and C _36, preferably between C ₂₀ and C _28, and more between C ₂₀ and C ₂ 2-

"Non-volatile" means an oil whose vapor pressure at ambient temperature and atmospheric pressure is non-zero and less than 0.02 mm Hg (2.66 Pa) and better still less than 1 0 ^{~ 3} mm of Hg (0.13 Pa).

Thus, as oils H 1, mention may be made of jojoba oil, linseed oil, Perilla oil, Inca Inchi oil, rose hip oil, rapeseed oil , hemp oil, sweet almond oil, corn oil, apricot oil, castor oil, Meadowfoam oil (INCI: Limnanthes Alba (Meadowfoam) Seed Oil) and mixtures thereof, preferably jojoba oil and / or Meadowfoam oil, and better Meadowfoam oil.

The use of oil (s) H 1, in particular Meadowfoam oil, in the fatty phase of the drops (G1) of an emulsion according to the invention has advantageous effects in terms of reduction of opacification of the continuous aqueous phase and / or adhesion of drops on the walls of the packaging and / or aggregation of drops between them.

According to a particular embodiment, the content of vegetable oil (s) in the fatty phase of the drops (G1) of an emulsion according to the invention is included between 0% and 40%, preferably between 0.1% and 25%, and in particular between 1% and 20%, by weight relative to the total weight of said fatty phase of the drops (G1).

According to one embodiment, the emulsions according to the invention comprise from 0% to 99.99%, preferably from 5% to 99.49%, in particular from 20% to 90%, and better still from 30% to 60%. , by weight of oil (s) relative to the total weight of the fatty phase of the drops (G1).

Drops (G2)

As indicated above, each drop (G1) comprises at least one drop (G2) comprising the internal aqueous phase. Preferably, each drop (G1) comprises a single drop (G2) comprising the internal aqueous phase.

A drop (G2) according to the invention is composed of a heart, also called inside the drop, surrounded by a bark, which isolates the inside of the drop of the fatty phase of the emulsion.

According to one embodiment, the size of the drops (G2) is greater than 10 μηι, or even greater than 50 μηι, and better is between 10 μηι and 2,000 μηι, in particular between 50 μηι and 1,500 μηι, better between 100 μηι. μηι and 1,100 μηι, in particular between 200 μηι and 800 μηι, and better still between 300 μηι and 700 μηι.

In particular, an emulsion according to the invention comprises from 0.01% to 50%, preferably from 0.1% to 40%, in particular from 1% to 30%, and more preferably from 2.5% to 20%, by weight of drops (G2) relative to the total weight of said emulsion.

According to one embodiment, and as indicated above, an emulsion according to the invention is obtained by a microfluidic process as defined below. As a result, the drops (G2) have a uniform size distribution. Preferably, the internal aqueous phase of the emulsions of the invention consists of a population of drops (G2) monodispersed, especially such that they have a mean diameter D of 10 μηι to 2000 μηι and a coefficient of variation Cv lower at 10%, or even less than 3%, measured according to the methods described above.

Preferably, the drops (G1) and (G2) are respectively monodisperse drops as defined above. For obvious reasons, for a given population of drops (G1), the mean diameter of the drops (G1) is greater than the average diameter of the drops (G2).

According to one embodiment, in the emulsions according to the invention, the volume fraction p (IF / (IF + MF) is between 0.1 and 0.7, preferably between 0.3 and 0.6, and better between 0.4 and 0.5, where: IF represents the total volume of the drops (G2), and

- MF represents the total volume of drops (G1) (and therefore without the total volume of drops (G2).

According to one embodiment, an emulsion according to the invention may comprise at least two populations of drops (G1) which differ from one another by, in particular, the diameter of the drops (G1) and / or the nature of the materials first drops (G1) and / or the raw material content of the drops (G1) and / or the diameter of the drops (G2) and / or the nature of the raw materials of the drops (G2) and / or the raw material content drops (G2).

By "raw materials" is meant any type of compound that may be used in the fatty phase of the drops (G1) and the internal aqueous phase of the drops (G2), in particular the cationic polymers, the anionic polymers, the oils, suspending agents, texturizing agents, the active agents and the additional compounds described in the present description.

Bark of the drops (G1) and (G2)

As mentioned above, the drops (G1) and (G2) according to the invention are surrounded by a bark (also referred to as "membrane").

According to the invention, the drops (G1) and (G2) obtained may have a very thin bark, in particular of thickness less than 1% of the diameter of the drops.

The thickness of the bark is thus preferably less than 1 μηι and is too small to be measured by optical methods.

According to one embodiment, the thickness of the bark of the drops (G1) and (G2) is less than 1000 nm, in particular between 1 and 500 nm, preferably less than 100 nm, advantageously less than 50 nm, preferably less than 10 nm, and most preferably 100 nm to 300 nm.

The measurement of the thickness of the bark of the drops (G1) and (G2) of the invention can be carried out by the method of small angle neutron scattering (Small-Angle X-ray Scattering), as implemented. Work in Sato et al. J. Chem. Phys. 1 1 1, 1393-1401 (2007).

For this, the drops are produced using deuterated water and are then washed three times with a deuterated oil, such as, for example, a deuterated hydrocarbon-type oil (octane, dodecane, hexadecane).

After washing, the drops are then transferred to the Neutrons cell to determine the l (q) spectrum; q being the wave vector. From this spectrum, classical analytical treatments (REF) are applied to determine the thickness of the hydrogenated (undeuterated) bark.

According to one embodiment, the bark surrounding the drops (G1) and (G2) is stiffened, which in particular gives good resistance to drops and reduces or even prevents their coalescence.

This bark is typically formed by coacervation, i.e. precipitation of charged polymers of opposite charges. Within a coacervate, the bonds binding the charged polymers to each other are of ionic type, and are generally stronger than bonds present within a surfactant-type membrane.

The bark is formed by coacervation of at least two charged polymers of opposite polarity (or polyelectrolyte) and preferably in the presence of a first polymer, of cationic type, and a second polymer, different from the first polymer, of the type anionic. These two polymers act as stiffening agents for the membrane.

The formation of the coacervate between these two polymers is generally caused by a modification of the conditions of the reaction medium (temperature, pH, reagent concentration, etc.). The coacervation reaction results from the neutralization of these two charged polymers of opposite polarities and allows the formation of a membrane structure by electrostatic interactions between the anionic polymer and the cationic polymer. The membrane thus formed around each drop typically forms a bark which completely encapsulates the heart of the drop and thus isolates the heart of the drop from the continuous aqueous phase.

Anionic Polymers (PA1) and (PA2)

The external aqueous phase comprises at least one anionic polymer (PA1) and the internal aqueous phase comprises at least one anionic polymer (PA2), these polymers (PA1) and (PA2) being identical or different.

Preferably, the anionic polymers (PA1) and (PA2) are hydrophilic, i.e., soluble or dispersible in water.

In the context of the present description, the term "anionic polymer" (or "anionic type polymer") a polymer having chemical functions of anionic type. We can also speak of anionic polyelectrolyte.

By "chemical function of the anionic type" is meant a chemical function AH capable of giving a proton to give a function A ^" . In the medium in which it is found, the anionic polymer therefore has chemical functions in AH form, or in the form of its conjugate base A ^" .

As an example of chemical functions of the anionic type, mention may be made of the carboxylic acid functions -COOH, optionally present in the form of a carboxylate anion -COO-.

As an example of anionic type polymer, there may be mentioned any polymer formed by the polymerization of monomers at least a part of which carries anionic type chemical functions, such as carboxylic acid functions. Such monomers are, for example, acrylic acid, maleic acid, or any ethylenically unsaturated monomer containing at least one carboxylic acid function. Thus, preferably, the anionic polymers (PA1) and (PA2), which are identical or different, are polymers comprising monomeric units comprising at least one carboxylic acid function.

Examples of suitable anionic polymers for carrying out the invention include copolymers of acrylic acid or maleic acid and other monomers, such as acrylamide, alkyl acrylates, alkyl acrylates, C ₅ -C ₈ alkyl acrylates oC -C ₃₀ alkyl methacrylates C12-C22, methoxypolyethylene glycol methacrylates, acrylates hydroxyester, the crosspolymères acrylates, and mixtures thereof.

According to one embodiment, the anionic polymers according to the invention are chosen from carbomers and crosslinked copolymers acrylates / Ci-30 alkyl acrylate. Preferably, the anionic polymers (PA1) and (PA2) according to the invention are carbomers.

According to one embodiment, the bark of the drops (G1) comprises at least one anionic polymer (PA1), such as for example a carbomer.

According to one embodiment, the bark of the drops (G2) comprises at least one anionic polymer (PA2), such as for example a carbomer.

In the context of the invention, and unless otherwise stated, the term "carbomer" means an optionally crosslinked homopolymer resulting from the polymerization of acrylic acid. It is therefore a poly (acrylic acid) optionally crosslinked.

Among the carbomers of the invention, mention may be made of those sold under the trade names Tego ^® Carbomer 340FD from Evonik, Carbopol ^® 981 from Lubrizol, Carbopol ETD 2050 from Lubrizol, or Carbopol Ultrez 10 from Lubrizol.

According to one embodiment, the term "carbomer" or "carbomer" or "Carbopol ^®" an acrylic acid polymer of high molecular weight cross-linked with allyl sucrose or allyl ethers of pentaerythritol (Handbook of Pharmaceutical Excipients, 5 ^th Edition, pIII). For example, it is the Carbopol ^® 10, Carbopol ^® 934, Carbopol ^® 934P, Carbopol 940 ^®, Carbopol ^® 941, Carbopol ^® 71 G, carbopol ^® 980, Carbopol ^® 971 P or Carbopol ^® 974P. According to one embodiment, the viscosity of said carbomer is between 4,000 and 60,000 cP at 0.5% w / w.

The carbomers have other names: polyacrylic acids, carboxyvinyl polymers or carboxy polyethylenes.

According to the invention, the anionic polymer (PA1) and / or (PA2) can also be a crosslinked copolymer acrylates / C _{1 0} - ₃ o alkyl acrylate (INCI name: acrylates / C ₁₀ - 30 alkyl acrylate Crosspolymer) as defined above.

According to the invention, the emulsions according to the invention may comprise a carbomer and a crosslinked copolymer acrylates / C _{1 0} - ₃ o alkyl acrylate.

According to one embodiment, an emulsion according to the invention comprises from 0.01% to 5%, preferably from 0.05% to 2%, and better still from 0.1% to 0.5%, by weight of polymer. (PA1) relative to the total weight of said emulsion.

According to one embodiment, an emulsion according to the invention comprises from 0.001% to 0.5%, preferably from 0.005% to 0.5%, and better still from 0.01% to 0.1%, by weight of polymer. (PA2) relative to the total weight of said emulsion.

According to the invention, the above-mentioned emulsion may comprise from 0.01% to 5%, preferably from 0.05% to 2%, and preferably from 0.1% to 0.5%, by weight of polymer (s). ) anionic (s) (PA1) and (PA2), in particular carbomer (s), relative to the total weight of said emulsion.

Cationic polymer

The dispersed fatty phase comprises at least one cationic polymer (PC).

Thus, the drops (G1) and (G2), and in particular the bark of said drops, further comprise at least one cationic type polymer. They may also include several cationic polymers. This cationic polymer is the one mentioned above which forms the bark by coacervation with the anionic polymer.

In the context of the present application, and unless otherwise stated, the term "cationic polymer" (or "cationic type polymer") a polymer having chemical functions of cationic type. We can also speak of cationic polyelectrolyte.

Preferably, the cationic polymer (PC) is lipophilic or fat-soluble. In the context of the present application, and unless otherwise stated, "chemical function of cationic type" means a chemical function B capable of capturing a proton to give a function BH ⁺ . Depending on the conditions of the medium in which it is located, the cationic type polymer therefore has chemical functions in B form, or in BH ⁺ form, its conjugated acid.

As an example of chemical functions of cationic type, mention may be made of the primary, secondary and tertiary amine functions, optionally present in the form of ammonium cations.

As an example of a cationic polymer, there may be mentioned any polymer formed by the polymerization of monomers at least a part of which carries chemical functions of cationic type, such as primary, secondary or tertiary amine functions.

Such monomers are, for example, aziridine, or any ethylenically unsaturated monomer containing at least one primary, secondary or tertiary amine function.

Among the examples of cationic polymers suitable for the implementation of the invention, there may be mentioned amodimethicone, derived from a silicone polymer (polydimethylsiloxane, also called dimethicone), modified by primary amine functions and secondary amine.

Mention may also be made of amodimethicone derivatives, for example copolymers of amodimethicone, aminopropyl dimethicone, and more generally linear or branched silicone polymers containing amine functions.

The bis-isobutyl copolymer PEG-14 / amodimethicone, Bis (C 13-15 Alkoxy) PG-Amodimethicone, Bis-Cetearyl Amodimethicone and bis-hydroxy / methoxy amodimethicone may be mentioned.

Mention may also be made of polysaccharide-type polymers comprising amine functions, such as chitosan or guar gum derivatives (hydroxypropyltrimonium guar chloride).

Mention may also be made of polypeptide-type polymers comprising amine functions, such as polylysine.

Mention may also be made of polyethyleneimine polymers comprising amine functions, such as linear or branched polyethyleneimine.

According to one embodiment, the drops, and in particular the bark of said drops, comprise a cationic polymer which is a silicone polymer modified with a primary, secondary or tertiary amine function, such as amodimethicone. According to one embodiment, the drops, and in particular the bark of said drops, comprise amodimethicone.

According to a particularly preferred embodiment, the cationic polymer (s) (PC) corresponds to the following formula (I):

(I) in which:

- Ri, R ₂ and R ₃ , independently of each other, represent OH or CH ₃ ;

R ₄ represents a -CH ₂ - group or a -X-NH- group in which X is a divalent C 3 or C 4 alkylene radical;

x is an integer between 10 and 5000, preferably between 30 and 1000, and more preferably between 80 and 300;

y is an integer between 2 and 1000, preferably between 4 and 100, and more preferably between 5 and 20; and

z is an integer between 0 and 10, preferably between 0 and 1, and more preferably equal to 1.

In formula (I) above, when R ₄ is -X-NH-, X is attached to the silicon atom.

In the aforementioned formula (I), R 1, R ₂ and R ₃ preferably represent

CH ₃ .

In the aforementioned formula (I), R ₄ is preferably - (CH ₂ ) ₃ -

NH-.

An amodimethicone is distinct / different from an oil such as those described above and capable of composing the fatty phase of the drops (G1) of an emulsion according to the invention.

According to the invention, the emulsion may comprise from 0.01% to 10%, preferably from 0.05% to 5%, by weight of cationic polymer (s) (PC), in particular amodimethicone ( s), relative to the total weight of the fatty phase of the drops

(G1). Internal aqueous phase

As indicated above, the drops (G2) according to the invention comprise an internal aqueous phase.

According to one embodiment, this aqueous phase has a viscosity of between 0 mPa.s and 10,000 mPa.s, preferably between 0 mPa.s and 2000 mPa.s, as measured at 25 ° C.

This viscosity is measured according to the method described above.

The internal aqueous phase of the emulsions comprises at least water.

According to one embodiment, the weight percentage of water of the internal aqueous phase is at least 30%, preferably at least 40%, in particular at least 50%, and better still at least 60%. %, especially between 70% and 98%, and preferably between 75% and 95%, relative to the total mass of said internal aqueous phase.

According to a particular embodiment, the external continuous aqueous phase and / or the internal aqueous phase may be in the form of an identical or different oil-in-water emulsion, said emulsion comprising a continuous aqueous phase. and a fatty phase dispersed in the form of drops (G3), the size of the drops (G3) being less than 500 μηι, preferably less than 400 μηι, in particular less than 300 μηι, better still less than 200 μηι, in particular less than 100 μηι, or even less than 20 μηι, and better still less than 10 μηι. Preferably, the size of the drops (G3) is between 0.1 and 200 μηι, preferably between 0.25 and 100 μηι, in particular between 0.5 μηι and 50 μηι, preferably between 1 μηι and 20 μηι, and better between 1 μηι and 10 μηι, or between 3 μηι and 5 μηι.

Optionally, the drops (G3) comprise a bark formed from at least one anionic polymer, which is identical to or different from the anionic polymers (PA1) and / or (PA2), and from at least one cationic polymer, which is identical to or different from the cationic polymer. (PC)

According to another particular embodiment, the fatty phase of the drops (G1) may be in the form of a water-in-oil emulsion, said emulsion comprising a continuous fatty phase and an aqueous phase dispersed in the form of drops (G4 ), the size of the drops (G4) being lower than the drops (G1) and preferably lower than the drops (G2). Preferably, the size of the drops (G4) is less than 500 μηι, preferably less than 400 μηι, in particular less than 300 μηι, better less than 200 μηι, in particular less than 100 μηι, or even less than 20 μηι, and better still less than 10 μηι. Preferably, the size of the drops (G4) is between 0.1 and 200 μηι, preferably between 0.25 and 100 μηι, in particular between 0.5 μηι and 50 μηι, preferably between 1 μηι and 20 μηι, and better between 1 μηι and 10 μηι, or between 3 μηι and 5 μηι.

Optionally, the drops (G4) comprise a bark formed of at least one anionic polymer, identical to or different from the anionic polymer (PA1), and at least one cationic polymer, which is identical to or different from the cationic polymer (PC).

Advantageously, the drops (G3) and / or (G4) are not macroscopic, that is to say, not visible to the naked eye.

In other words, the drops (G3) and / or (G4) are different and independent of the drops (G1) and / or (G2). Moreover, when the drops (G3) are present at the level of the internal aqueous phase, the size of the drops (G3) is smaller than the size of the drops (G2).

These drops (G3) and / or (G4) of reduced size allow to have an effect on the texture. Indeed, an emulsion according to the invention comprising such drops (G3) and / or (G4) finely dispersed has yet improved lubricity qualities.

The presence of drops (G3) and / or (G4) enhances the characteristics of an emulsion according to the invention in terms of unique texture, lightness and progressive sensory. More particularly, an emulsion according to the invention comprising drops (G3) and / or (G4) spreads easily on the skin. The first moments of application are very aqueous with a marked brittle effect. Then, the feeling evolves towards an oily veil that fades to leave a light and hydrated skin. This texture is particularly advantageous and surprising to the skilled person in view of the absence of surfactants in these emulsions.

Agent with suspensive power

According to one embodiment, the fatty phase of the drops (G1) comprises at least one agent having suspensive power (or suspensive agent). Such a suspending agent is different from the anionic and cationic polymers described above.

In the context of the invention, and unless otherwise stated, the term "agent having suspensive power" means an agent capable of stably maintaining the drops (G2) in the drops (G1) in a stable manner. Such an embodiment is advantageous in that the presence of at least one suspending agent in the fatty phase of the drops (G1) further enhances the kinetic stability of an emulsion according to the invention, and in particular the stability of the drops ( G1) and (G2). Thus, the drops (G1) and (G2) may remain intact on a time scale greater than 1 month, in particular greater than 3 months, or even greater than 6 months, at ambient temperature, for example T = 25 ° C ± 2 C., and at ambient pressure, for example 1013 mbar.

In the context of the invention, and unless otherwise indicated, "suspending agents" means an agent for increasing the viscosity of the fatty phase of the drops (G1) of the emulsion without said suspending agent, and to attain a final viscosity of the fatty phase of the drops (G1) greater than 20,000 mPa.s, preferably greater than 50,000 mPa.s, better still greater than 100,000 mPa.s, and more particularly greater than 200,000 mPa.s.

Preferably, the viscosity of the fatty phase of the drops (G1) of the emulsion in the presence of said suspending agent is between 20,000 and 100,000,000 mPa.s, preferably between 50,000 and 1,000,000 mPa.s, and best between 100,000 to 500,000 mPa.s at 25 ° C.

The choice of agent (s) suspensive (s) is carried out in particular with regard to the nature of the fatty phase of the drops (G1) and / or desired results, especially in terms of sensoriality and / or texture. For obvious reasons of compatibilities, the suspending agent is lipophilic or fat-soluble.

Also, when the fatty phase of the drops (G1) comprises at least one oil and at least one suspensive agent, the choice of oil (s) is carried out in particular with regard to the nature of the suspensive agent (s) and vice versa. In fact, the oil (s) used must be a satisfactory solvent for the suspending agent. This choice is within the general skills of those skilled in the art.

According to one embodiment, the emulsions according to the invention comprise from 0% to 99.99%, preferably from 0.5% to 70%, in particular from 1% to 50%, better still from 2% to 40%, in particular from 2.5% to 30%, and preferably from 10% to 20%, by weight of suspensive agent (s) relative to the total weight of the fatty phase of the drops (G1).

According to one embodiment, the suspending agent is chosen from organic or inorganic, polymeric or molecular lipophilic suspending agents, solid fats at ambient temperature and pressure, and mixtures thereof. Suspensive agent (s) lipophilic (s)

The suspending agents that may be used according to the invention may be organic or inorganic, polymeric or molecular lipophilic suspending agents.

According to one embodiment, the suspending agent is chosen from the group consisting of modified clays, silicas, such as fumed silica, and mixtures thereof.

As inorganic lipophilic suspending agent, there may be mentioned optionally modified clays, such as hectorites modified with a C ₁₀ to C ₂₂ ammonium chloride, such as hectorite modified with di-stearyl dimethyl ammonium chloride, such as example, that sold under the name Bentone 38V ^® by Elementis. Mention may also be made of hectorite modified with distearyldimethylammonium chloride, also known as quaternium-18 bentonite, such as the products sold or manufactured under the names Bentone 34 by the company Rheox, Claytone XL, Claytone 34 and Claytone 40 marketed or manufactured by Southern Clay, modified clays known as benzalkonium and quaternium-18 bentonites and marketed or manufactured under the names Claytone HT, Claytone GR and Claytone PS by Southern Clay, chloride-modified clays stearyldimethylbenzoylammonium compounds, known as steralkonium bentonites, such as the products marketed or manufactured under the names Claytone APA and Claytone AF by Southern Clay, and Baragel 24 sold or manufactured by Rheox.

It is also possible to mention fumed silica optionally treated with hydrophobic surface, the particle size of which is less than 1 μηι. It is indeed possible to chemically modify the surface of the silica, by chemical reaction generating a decrease in the number of silanol groups present on the surface of the silica. In particular, it is possible to substitute silanol groups with hydrophobic groups: a hydrophobic silica is then obtained.

The hydrophobic groups can be:

trimethylsiloxyl groups, which are especially obtained by treatment of fumed silica in the presence of hexamethyldisilazane. Silicas thus treated are named "Silica Silylate" according to the CTFA (8 ^th edition, 2000). They are for example marketed under the references Aerosil R812 ^® by Degussa, Cab-O-Sil TS-530 ^® by the company Cabot; or dimethylsilyloxyl or polydimethylsiloxane groups, which are especially obtained by treating fumed silica in the presence of polydimethylsiloxane or dimethyldichlorosilane. Silicas thus treated are known as "silica dimethyl Silylate" according to the CTFA ^(8th edition, 2000). They are for example marketed under the references Aerosil R972 ^® , and Aerosil R974 ^® by the company DEGUSSA, CAB-O-SIL TS-610 ^® and CAB-O-SIL TS-720 ^® by CABOT.

The hydrophobic fumed silica has in particular a particle size that can be nanometric to micrometric, for example ranging from about 5 to 200 nm.

The polymeric organic lipophilic suspending agents are, for example elastomeric organopolysiloxanes partially or totally crosslinked, three-dimensional structure, such as those sold under the names KSG6 ^®, ^® KSG16 and KSG18 ^® by the company Shin-Etsu, Dow Corning® EL- 7040, Trefil E-505C ^® and Trefil E-506C ^® by Dow-Corning company, of Gransil SR-CYC ^®, SR DMF10 ^®, SR-DC556 ^®, SR 5CYC ^® gel, SR DMF 10 ^® gel and SR DC 556 gel ^® by the company GRANT INDUSTRIES, SF 1204 ^® and JK 1 13 ^® by the company GENERAL ELECTRIC; ethyl cellulose such as that sold under the name Ethocel ^® by Dow Chemical; galactomannans comprising from one to six, particularly two to four hydroxyl groups per saccharide, substituted with a saturated alkyl chain or not, such as guar gum alkylated with alkyl chains to C _6, and in particular C 1 to C ₃ and mixtures thereof. Block copolymers of "diblock", "triblock" or "radial" of the polystyrene / polyisoprene or polystyrene / polybutadiene type such as those marketed under the name Luvitol HSB ^® by the company BASF, of the polystyrene / copoly (ethylene-propylene) such as those marketed under the trademark Kraton ^® by the company Shell Chemical Co., or the polystyrene / copoly (ethylene-butylene), triblock and radial copolymers of the mixtures (star) in isododecane such as those sold by the PENRECO company under the name Versagel ^® such as the mixture of butylene / ethylene / styrene triblock copolymer and star copolymer ethylene / propylene / styrene in isododecane (Versagel M 5960).

According to one embodiment, the suspending agents that may be used according to the invention may be chosen from the group consisting of polyacrylates; sugar / polysaccharide esters and fatty acid (s), in particular esters of dextrin and fatty acid (s), esters of inulin and fatty acid (s) or esters of glycerol and fatty acid (s); polyamides; and their mixtures.

As lipophilic suspensive agent, mention may also be made of polymers having a weight average molecular weight of less than 100,000, comprising a) a polymeric backbone having hydrocarbon-based repeating units provided with at least one heteroatom, and optionally b) at least one chain pendent fat and / or at least one optionally functionalized terminal fatty chain having from 6 to 120 carbon atoms and being bonded to these hydrocarbon units, as described in applications WO 02/056847, WO 02/47619, in particular the resins polyamides (especially comprising alkyl groups having from 12 to 22 carbon atoms) such as those described in US 5783657.

For example, polyamide resin that can be implemented according to the present invention include UNICLEAR 100 VG ^® marketed by Arizona Chemical.

It is also possible to use polyorganosiloxane type silicone polyamides such as those described in US Pat. No. 5,874,069, US Pat. No. 5,919,441, US Pat. No. 6,051,216 and US Pat. No. 5,981,680.

These silicone polymers can belong to the following two families:

polyorganosiloxanes comprising at least two groups capable of establishing hydrogen interactions, these two groups being located in the polymer chain, and / or

polyorganosiloxanes comprising at least two groups capable of establishing hydrogen interactions, these two groups being located on grafts or branches.

Among the lipophilic suspensive agents that can be used in the present invention, mention may also be made of dextrin and fatty acid esters, such as dextrin palmitates.

According to one embodiment, the ester of dextrin and fatty acid (s) according to the invention is a dextrin mono- or poly-ester and of at least one fatty acid corresponding to the following formula (II):

in which : an integer from 2 to 200, preferably from 20 to 150, and in particular from 25 to 50,

the radicals R _4, R ₅ and R _{6, which are} identical or different, are chosen from hydrogen or an acyl group -COR _a in which the radical R _a represents a hydrocarbon radical, linear or branched, saturated or unsaturated, having 5 to 50, preferably 5 to 25 carbon atoms,

provided that at least one of said radicals R ₄ , R ₅ or R ₆ is other than hydrogen.

According to one embodiment, R _{4 1} R ₅ and R ₆ represent, independently of each other, H or an acyl group -COR _a in which R _a is a hydrocarbon radical as defined above, provided that at least two of said radicals R _4, R ₅ or R ₆ are identical and different from hydrogen.

According to one embodiment, when the radicals R _4, R ₅ and R ₆ , which are identical or different, represent a radical -COR _a , they can be chosen from the radicals caprylyl, caproyl, lauroyl, myristyl, palmityl, stearyl, eicosanyl, docosanoyl, isovaleryl, 2-ethylbutyryl, ethylmethylacetyl, isoheptanyl, 2-ethylhexanyl, isononanyl, isodecanyl, isotridecanyl, isomyristyl, isopalmityl, isostearyl, isohexanyl, decenyl, dodecenyl, tetradecenyl, myristyl, hexadecenoyl, palmitolyl, oleyl, elaidyl, eicosenyl, sorbyl, linoleyl, linolenyl, punicyl, arachidonyl, stearolyl, and mixtures thereof.

Among the esters of dextrin and fatty acid (s), mention may be made, for example, of dextrin palmitates, dextrin myristates, dextrin palmitates / ethylhexanoates and mixtures thereof.

Mention may in particular be made of the esters of dextrin and of fatty acid (s) marketed under the names Rheopearl® KL2 (INCI name: dextrin palmitate), Rheopearl® TT2 (INCI name: dextrin palmitate ethylhexanoate), and Rheopearl® MKL2 (INCI name myristate dextrin) by Miyoshi Europe.

Among the lipophilic gelling agents that can be used in the present invention, mention may also be made of inulin and fatty acid esters.

Mention may in particular be made of the esters of inulin and fatty acid (s) sold under the names Rheopearl® ISK2 or Rheopearl® ISL2 (INCI name: Stearoyl Inulin) by the company Miyoshi Europe

According to one embodiment, the suspending agent is selected from polyacrylates resulting from the polymerization of acrylate (s), alkyl C ₁₀ -C _30, preferably acrylate (s) -C ₄ alkyl - -C ₂ 4, and even more preferably acrylate (s) alkyl ₈ -C _22. According to one embodiment, the polyacrylates are polymers of acrylic acid esterified with a fatty alcohol whose saturated carbon chain comprises from 10 to 30 carbon atoms, preferably from 14 to 24 carbon atoms, or a mixture of said fatty alcohols . Preferably, the fatty alcohol comprises 18 carbon atoms or 22 carbon atoms.

Among the polyacrylates, there may be mentioned more particularly stearyl polyacrylate, behenyl polyacrylate. Preferably, the suspending agent is stearyl polyacrylate or behenyl polyacrylate.

Mention may be made in particular of the polyacrylates sold under the names Intelimer® (INCI name: Poly C ₁₀ -C ₃₀ alkyl acrylate), in particular Intelimer® 13.1 and Intelimer® 13.6, by the company Airproducts.

According to one embodiment, the suspending agent is an ester of glycerol and fatty acid (s), in particular a mono-, di- or triester of glycerol and fatty acid (s). Typically, said ester of glycerol and fatty acid (s) may be used alone or as a mixture.

According to the invention, it may be a glycerol ester and a fatty acid or a glycerol ester and a mixture of fatty acids.

According to one embodiment, the fatty acid is selected from the group consisting of behenic acid, isooctadecanoic acid, stearic acid, eicosanoic acid, and mixtures thereof.

According to one embodiment, the ester of glycerol and fatty acid (s) has the following formula (III):

in which: R 1, R ₂ and R ₃ are, independently of one another, chosen from H and a saturated alkyl chain comprising from 4 to 30 carbon atoms, at least one of R 1, R ₂ and R ₃ being different from H.

According to one embodiment, R _1; R ₂ and R ₃ are different.

According to one embodiment, R _1; R ₂ and / or R ₃ represents a saturated alkyl chain comprising from 4 to 30, preferably from 12 to 22, and preferably from 18 to 22 carbon atoms.

According to one embodiment, the ester of glycerol and fatty acid (s) corresponds to a compound of formula (III) in which R 1 = H, R ₂ = C ₂₁ H ₄₃ and R ₃ = C ₁₉ H ₄₀ . According to one embodiment, the ester of glycerol and of fatty acid (s) corresponds to a compound of formula (III) in which R 1 = R ₂ = R ₃ = C ₂ H ₄₃ .

According to one embodiment, the ester of glycerol and fatty acid (s) corresponds to a compound of formula (III) in which R 1 = R ₂ = H, and R ₃ = Ci ₉ H ₄₀ .

According to one embodiment, the ester of glycerol and of fatty acid (s) corresponds to a compound of formula (III) in which R 1 = R ₂ = H, and R ₃ = C ₁₇ H ₃₅ .

Mention may in particular be made of the esters of glycerol and of fatty acid (s) marketed under the names Nomcort HK-G (INCI name: Glyceryl behenate / eicosadioate) and Nomcort SG (INCI name: Glyceryl tribehenate, isostearate, eicosadioate), by the Nisshin Oillio company.

Wax (es)

For the purposes of the invention, the term "wax" means a lipophilic compound, solid at room temperature (25 ° C.), with reversible solid / liquid state change, having a melting point greater than or equal to 30 ° C. up to 120 ° C.

The protocol for measuring this melting point is described below.

The waxes that may be used in an emulsion according to the invention may be chosen from waxes, solid, deformable or not at room temperature, of animal, vegetable, mineral or synthetic origin, and mixtures thereof.

In particular, it is possible to use hydrocarbon-based waxes such as beeswax, lanolin wax, and Chinese insect waxes; rice wax, Carnauba wax, Candelilla wax, Ouricurry wax, Alfa wax, cork fiber wax, sugar cane wax, Japanese wax and sumac wax ; montan wax, microcrystalline waxes, paraffins and ozokerite; polyethylene waxes, waxes obtained by Fisher-Tropsch synthesis and waxy copolymers and their esters.

Mention may be made in particular of the waxes marketed under the names Kahlwax®2039 (INCI name: Candelilla cera) and Kahlwax®6607 (INCI name: Helianthus Annuus Seed Wax) by the company Kahl Wachsraffinerie, Casid HSA (INCI name: Hydroxystearic Acid) by the SACI company CFPA, Performa®260 (INCI name: Synthetic wax) and Performa®103 (INCI name: Synthetic wax) by the company New Phase, and AJK-CE2046 (INCI name: Cetearyl alcohol, dibutyl lauroyl glutamide, dibutyl ethylhaxanoyl glutamide) by the company Kokyu Alcohol Kogyo.

Mention may also be made of waxes obtained by catalytic hydrogenation of animal or vegetable oils having linear or branched C ₈ -C ₃₂ fatty chains. Among these, there may be mentioned hydrogenated jojoba oil, hydrogenated sunflower oil, hydrogenated castor oil, hydrogenated coconut oil and hydrogenated lanolin oil, di-tetrastearate ( trimethylol-1, 1, 1 propane) sold under the name "HEST 2T-4S" by the company HETERENE, di- (trimethylol-1, 1, 1 propane) tetraprenate sold under the name HEST 2T-4B by the company HETERENE.

One can also use waxes obtained by transesterification and hydrogenation of vegetable oils, such as castor oil or olive oil, such as waxes sold under the names Phytowax ricin 16L64 and 22L73 ^® ^® and Phytowax Olive 18L57 by the company Sophim. Such waxes are described in application FR-A-2792190.

It is also possible to use silicone waxes, which may advantageously be substituted polysiloxanes, preferably at a low melting point.

Among the commercial silicone waxes of this type, mention may be made in particular of those sold under the names Abilwax 9800, 9801 or 9810 (GOLDSCHMIDT), KF910 and KF7002 (SHIN ETSU), or 176-1 1 18-3 and 176-1 1481 (GENERAL ELECTRIC).

The silicone waxes that may be used may also be alkyl or alkoxydimethicones such as the following commercial products: Abilwax 2428, 2434 and 2440 (GOLDSCHMIDT), or VP 1622 and VP 1621 (WACKER), as well as (C ₂ o C ₆ o) alkyldimethicones , in particular the (C30-C45) alkyldimethicones, such as the silicone wax sold under the name SF-1642 by the company GE-Bayer Silicones.

It is also possible to use hydrocarbon waxes modified with silicone or fluorinated groups such as, for example: siliconyl candelilla, siliconyl beeswax and Fluorobeeswax by Koster Keunen.

The waxes may also be chosen from fluorinated waxes.

Butter (s) or pasty fat

For the purposes of the present invention, the term "butter" (also referred to as "pasty fatty substance") is understood to mean a lipophilic fatty compound with a reversible solid / liquid state change and comprising at the temperature of 25 ° C. a liquid fraction and a fraction. solid, and at atmospheric pressure (760 mm Hg). In other words, the starting melting temperature of the pasty compound may be less than 25 ° C. The liquid fraction of the pasty compound measured at 25 ° C. may represent from 9% to 97% by weight of the compound. This liquid fraction at 25 ° C. is preferably between 15% and 85%, more preferably between 40 and 85% by weight. Preferably, the one or more butters have an end-of-melting temperature of less than 60 ° C. Preferably, the one or more butters have a hardness less than or equal to 6 MPa.

Preferably, the butters or pasty fatty substances have in the solid state an anisotropic crystalline organization, visible by X-ray observations.

For the purposes of the invention, the melting temperature corresponds to the temperature of the most endothermic peak observed in thermal analysis (DSC) as described in the ISO 1 1357-3 standard; 1999. The melting point of a paste or a wax can be measured using a differential scanning calorimeter (DSC), for example the calorimeter sold under the name "DSC Q2000" by the company TA Instruments .

Concerning the measurement of the melting temperature and the determination of the end-of-melting temperature, the sample preparation and measurement protocols are as follows: A sample of 5 mg of pasty fatty substance (or butter) or wax previously heated at 80 ° C. and taken with magnetic stirring using an equally heated spatula is placed in an airtight aluminum capsule or crucible. Two tests are carried out to ensure the reproducibility of the results.

The measurements are carried out on the calorimeter mentioned above. The oven is subjected to a nitrogen sweep. The cooling is ensured by the RCS 90 heat exchanger. The sample is then subjected to the following protocol, first being brought to a temperature of 20 ° C and then subjected to a first temperature rise ranging from 20 ° C to 80 ° C. ° C, at the heating rate of 5 ° C / minute, then cooled from 80 ° C to -80 ° C at a cooling rate of 5 ° C / minute and finally subjected to a second temperature rise from - 80 ° C to 80 ° C at a heating rate of 5 ° C / minute. During the second rise in temperature, the variation of the power difference absorbed by the empty crucible and the crucible containing the butter sample is measured as a function of temperature. The melting point of the compound is the value of the temperature corresponding to the peak apex of the curve representing the variation of the difference in power absorbed as a function of the temperature. The end of melting temperature corresponds to the temperature at which 95% of the sample melted.

The liquid fraction by weight of the butter (or pasty fatty substance) at 25 ° C is equal to the ratio of the enthalpy of fusion consumed at 25 ° C on the heat of fusion of the Butter. The enthalpy of melting of the butter or pasty compound is the enthalpy consumed by the compound to pass from the solid state to the liquid state.

The butter is said to be in the solid state when the entirety of its mass is in crystalline solid form. The butter is said to be in the liquid state when the entirety of its mass is in liquid form. The melting enthalpy of the butter is equal to the integral of the whole of the melting curve obtained with the aid of the calorimeter evoked, with a rise in temperature of 5 ° C. or 10 ° C. per minute, according to the standard ISO 1,1357-3: 1999. The melting enthalpy of the butter is the amount of energy required to pass the compound from the solid state to the liquid state. It is expressed in J / g.

The enthalpy of fusion consumed at 25 ° C is the amount of energy absorbed by the sample to change from the solid state to the state it has at 25 ° C consisting of a liquid fraction and a solid fraction. The liquid fraction of the butter measured at 32 ° C preferably represents from 30% to 100% by weight of the compound, preferably from 50% to 100%, more preferably from 60% to 100% by weight of the compound. When the liquid fraction of the butter measured at 32 ° C is 100%, the temperature of the end of the melting range of the pasty compound is less than or equal to 32 ° C. The liquid fraction of the butter measured at 32 ° C. is equal to the ratio of the enthalpy of fusion consumed at 32 ° C. on the enthalpy of melting of the butter. The enthalpy of fusion consumed at 32 ° C. is calculated in the same way as the heat of fusion consumed at 23 ° C.

Regarding the hardness measurement, the sample preparation and measurement protocols are as follows: the emulsion according to the invention or the butter is placed in a mold 75 mm in diameter which is filled to about 75% of its height . In order to overcome the thermal past and control the crystallization, the mold is placed in the Vôtsch VC0018 programmable oven where it is first heated to 80 ° C for 60 minutes, then cooled from 80 ° C to 0 ° C at a cooling rate of 5 ° C / minute, then left at the stabilized temperature of 0 ° C for 60 minutes, then subjected to a temperature rise from 0 ° C to 20 ° C, at a rate of heat of 5 ° C / minute, then left at the stabilized temperature of 20 ° C for 180 minutes. The compression force measurement is performed with Swantech TA / TX2i texturometer. The mobile used is chosen according to the texture: - mobile cylindrical steel 2 mm in diameter for very rigid raw materials; - Cylindrical 12 mm diameter steel for rigid raw materials. The measurement comprises 3 steps: a first step after automatic detection of the surface of the sample where the mobile moves at the measuring speed of 0.1 mm / s, and enters the emulsion according to the invention or the butter at a depth of penetration of 0.3 mm, the software notes the value of the maximum force reached; a second so-called relaxation stage where the mobile stays at this position for one second and where the force is noted after 1 second of relaxation; finally a third so-called withdrawal step where the mobile returns to its initial position at the speed of 1 mm / s and the energy of withdrawal of the probe (negative force) is recorded.

The value of the hardness measured in the first step corresponds to the maximum compression force measured in Newton divided by the surface area of the texturometer cylinder expressed in mm ² in contact with the butter or emulsion according to the invention. The value of hardness obtained is expressed in mega-pascals or MPa.

The pasty fatty substance or butter may be chosen from synthetic compounds and compounds of plant origin. A pasty fatty substance can be obtained synthetically from starting materials of plant origin.

The pasty fatty substance is advantageously chosen from:

lanolin and its derivatives such as lanolin alcohol, oxyethylenated lanolins, acetylated lanolin, lanolin esters such as isopropyl lanolate, oxypropylenated lanolines,

polymeric or non-polymeric silicone compounds, such as polydimethylsiloxanes of high molecular weight, polydimethylsiloxanes with side chains of the alkyl or alkoxy type having from 8 to 24 carbon atoms, especially stearyl dimethicones,

polymeric or non-polymeric fluorinated compounds,

vinyl polymers, in particular

homopolymers of olefins,

copolymers of olefins,

homopolymers and copolymers of hydrogenated dienes,

linear or branched oligomers, homo or copolymers of alkyl (meth) acrylates preferably having a C ₈ -C ₃₀ alkyl group,

homo and copolymeric oligomers of vinyl esters having C ₈ -C ₃₀ alkyl groups,

the homo- and copolymer oligomers of vinyl ethers having C ₈ -C ₃₀ alkyl groups,

the liposoluble polyethers resulting from the polyetherification between one or more C ₂ -C ₀ 0 diols, preferably C ₂ -C ₅ o diols,

esters and polyesters, and - their mixtures.

According to a preferred embodiment of the invention, the particular butter or butters are of plant origin such as those described in Ullmann's Encyclopedia of Industrial Chemistry ("Fats and Fatty Oils", A. Thomas, published on 15/06/2000, D01 : 10.1002 / 14356007.a10_173, point 13.2.2.2F, Shea Butter, Borneo Tallow, and Related Fats (Vegetable Butters).

Mention may be made more particularly of C10-C18 triglycerides (INCI name: C10-18 triglycerides) having at a temperature of 25 ° C and at atmospheric pressure (760 mm Hg) a liquid fraction and a solid fraction, shea butter, Nilotica Shea butter (Butyrospermum parkii), Galam butter (Butyrospermum parkii), Borneo butter or fat or Tengkawang tallow) (Shorea stenoptera), Shorea butter, Illipé butter, Madhuca butter or Bassia Madhuca longifolia, mowrah butter (Madhuca Latifolia), Katiau butter (Madhuca mottleyana), Phulwara butter (M. butyracea), mango butter (Mangifera indica), Murumuru butter (Astrocatyum murumuru), Kokum butter (Garcinia Indica), Ucuuba butter (Virola sebifera), Tucuma butter, Painya butter (Kpangnan) (Pentadesma butyracea), Coffee butter (Coffea arabica), Apricot butter (Prunus Armeniaca) , Macadamia butter (Macadamia Temifolia), butter of p grape pine (Vitis vinifera), avocado butter (Persea gratissima), olive butter (Olea europaea), sweet almond butter (Prunus amygdalus dulcis), cocoa butter (Theobroma cacao) and sunflower butter, butter under the INCI name Astrocaryum Murumuru Seed Butter, butter under the INCI name Theobroma Grandiflorum Seed Butter, and butter under the INCI name Irvingia Gabonensis Kernel Butter, jojoba esters (mixture of wax and oil hydrogenated jojoba) (INCI name: Jojoba esters) and ethyl esters of shea butter (INCI name: Shea butter ethyl esters), and mixtures thereof.

According to a preferred embodiment, a suspending agent for the fatty phase of the drops (G1) according to the invention is a heat-sensitive suspensive agent, namely which reacts with heat, and in particular is a suspending agent which is solid at room temperature and liquid at a temperature of temperature above 40 ° C, preferably above 50 ° C.

Thus, the suspending agent is preferably chosen from dextrin palmitates.

According to another preferred embodiment, a suspending agent for the fatty phase of the drops (G1) according to the invention is a thixotropic or suitable suspending agent. to confer on the solution which includes it a thixotropic behavior. This embodiment is advantageous in that an emulsion according to the invention can be obtained by implementing a microfluidic process at ambient temperature. Thus, the suspending agent is preferably chosen from the optionally hydrophobic silica treated surface-treated.

According to one particular embodiment, an emulsion according to the invention, in particular the fatty phase of the drops (G1), does not comprise an elastomer gel comprising at least one dimethicone, in particular such as marketed by NuSil Technology under the name CareSil ™ CXG-1 104 (INCI: Dimethicone (and) Dimethicone / Vinyl Dimethicone Crosspolymer).

Advantageously, when the fatty phase of the drops (G1) of an emulsion according to the invention further comprises at least one suspending agent as described above, in particular chosen from the esters of dextrin and fatty acid (s) and preferably in the group consisting of dextrin palmitates, dextrin myristates, dextrin palmitates / ethylhexanoates, and mixtures thereof, said fatty phase of the drops (G1) further comprises at least one oil having a refractive index close to that of the suspending gelling agent (s), namely an oil having a refractive index, at ambient temperature (25 ° C.) and atmospheric pressure, of between 1, 2 and 1.8, preferably between 1, 3 and 1, 7, in particular between 1, 4 and 1, 6, and more preferably between 1, 45 and 1, 55.

This embodiment is advantageous in that it makes it possible to improve the transparency of the fatty phase of the drops (G1), and therefore the transparency of the emulsion according to the invention.

Advantageously, the oil having a refractive index between 1, 2 and 1.8 is a silicone oil, in particular a phenyl silicone oil.

As silicone oils in accordance with the invention, mention may be made, for example, of volatile or non-volatile polymethylsiloxanes (PDMSs) with a linear or cyclic silicone chain, which are liquid or pasty at room temperature, in particular cyclopolydimethylsiloxanes (cyclomethicones) such as cyclohexasiloxane. and cyclopentasiloxane; polydimethylsiloxanes (or dimethicones) comprising alkyl, alkoxy or phenyl groups, during or at the end of the silicone chain, groups having from 2 to 24 carbon atoms; phenyl silicones such as phenyltrimethicones (in particular diphenylsiloxyphenyltrimethicone), phenyldimethicones, phenyltrimethylsiloxydiphenylsiloxanes, diphenyl-dimethicones, diphenylmethyldiphenyltrisiloxanes, 2-phenylethyltrimethylsiloxysilicates, polymethylphenylsiloxanes, and mixtures thereof. Texture agent (s)

According to the fluidity and / or the sensoriality and / or the texture of the emulsion according to the invention which it is desired to obtain, said emulsion, in particular the external aqueous phase and / or the internal aqueous phase, may be further comprising at least one texturizing agent different from the cationic polymers, anionic polymers, oils and suspending agents described above.

Of course, those skilled in the art will take care to choose any texture agent (s) and / or their amount (s) in such a way that the advantageous properties of an emulsion according to invention are not or not substantially impaired by the addition contemplated.

Advantageously, an emulsion according to the invention comprises from 0.01% to 50%, preferably from 0.05% to 30%, in particular from 0.1% to 15%, better still from 1% to 10%, and all particularly 2% to 5% by weight of texturizing agent (s) relative to the total weight of said emulsion.

In particular, when the external aqueous phase comprises at least one texturizing agent, an emulsion according to the invention comprises from 0.01% to 50%, preferably from 0.05% to 30%, in particular 0.1% at 15%, more preferably from 1% to 10%, and most preferably from 2% to 5%, by weight of texturizing agent (s) relative to the total weight of said external aqueous phase.

In particular, when the internal aqueous phase comprises at least one texturizing agent, an emulsion according to the invention comprises from 0.01% to 30%, preferably from 0.05% to 15%, and in particular from 0.1% to % to 10%, by weight of texturizing agent (s) relative to the total weight of said internal aqueous phase.

As hydrophilic texture agents, that is to say those which are soluble or dispersible in water, and therefore may be present in the external aqueous phase and / or the internal aqueous phase of an emulsion according to the invention, mention may be made of :

natural texture agents, chosen in particular from algae extracts, plant exudates, seed extracts, exudates of microorganisms, such as alcasealan (INCI: Alcaligenes Polysaccharides), and other natural agents, in particular hyaluronic acid,

semi-synthetic texture agents, especially chosen from cellulose derivatives and modified starches,

synthetic texturing agents, especially chosen from homopolymers of (meth) acrylic acid or one of their esters, copolymers of (meth) acrylic acid or one of their esters, copolymers of AMPS (2-acrylamido-2-methylpropanesulfonic acid), associative polymers,

the other texturing agents, especially chosen from glycols, polyethylene glycols (sold under the name Carbowax), clays, silicas such as those sold under the names Aerosil® 90/130/150/200/300/380), in particular glycerine, propylene glycol, butylene glycol, penthylene glycol, propanediol, methylpropanediol, hexanediol, and

- their mixtures.

For the purposes of the present invention, the term "associative polymer" means any amphiphilic polymer comprising in its structure at least one fatty chain and at least one hydrophilic portion; the associative polymers according to the present invention may be anionic, cationic, nonionic or amphoteric; these include those described in FR 2 999 921. Preferably, these are amphiphilic and anionic associative polymers and amphiphilic and nonionic associative polymers as described below.

Preferably, the texturing agents of the aqueous phase are chosen from those which are resistant to electrolytes, and are especially chosen from carrageenans; xanthan gum; carboxymethylcellulose; hydroxyethylcellulose; hydroxypropylcellulose; hydroxypropyl methylcellulose; methylcellulose; ethylcellulose; alkylhydroxyethylcelluloses; hydroxypropyl starch phosphate; the carbomers represented by those sold under the names Carbopol Ultrez 10/30, Tego Carbomer 134/140/141, Aqupec HV-505, HV-505HC, HV-504, HV-501, HV-505E, HV-504E, HV-504, 501 E, HV-505ED, Ashland 941 carbomer, or Ashland 981 carbomer; acrylate copolymers, in particular those sold under the names Carbopol Aqua SF-1 Polymer or Carbopol Aqua SF-1 OS Polymer or Arkema Reostyl 67N; the acrylates / C10-C30 alkyl acrylate crosspolymers sold under the names Carbopol Ultrez 20/21, Tego Carbomer 341 ER, Tego Carbomer 750 HD, Tego Carbomer 841 SER, Aqupec HV-501 ER, HV-701 EDR, HV-501 EM, SER W-150C or SER W-300C; sodium acrylates / beheneth-25 methacrylate crosspolymer; acrylates / acrylamide copolymers; the AMPS Na hydroxyethyl acrylate copolymers sold under the names Sepinov WEO or Sepinov EMT 10; acryloyl Dimethyltaurate / Sodium Acrylate / Dimethylacrylamide crosspolymers; PVP; acrylates / Steareth-20 Methacrylate Copolymer; Polyacrylate Crosspolymer-6; acrylates / ceteth-20 itaconate copolymer; the polyurethanes, for example Steareth-100 / PEG-136 / HDI Copolymer sold under the name RHEOLUXE® 81 1 by Elementis specialitis, in particular polyether polyurethanes such as PEG-240 / HDI COPOLYMER BIS-DECYLTETRADECETH-20 ETHER, in particular those sold under the names Adeka Nol GT-700 / GT-730; polyurethane-39; cetyl hydroxyethylcellulose; polyethylene glycols; bentonite; glycerine; and mixtures thereof, and more preferably are selected from acrylate copolymers, in particular that sold under the name Carbopol Aqua SF-1 Polymer or Carbopol Aqua SF-1 OS Polymer.

These texture agents, in addition to their property (s) of resistance to electrolytes, give an emulsion according to the invention comprising them improved stability and transparency.

Additional compound (s)

According to the invention, the internal aqueous phase and / or the external aqueous phase and / or the fatty phase may further comprise at least one additional compound different from the anionic and cationic polymers, the suspending agent, the agent texture and oils mentioned above.

An emulsion according to the invention, and in particular the internal aqueous phase and / or the external aqueous phase and / or the fatty phase of said emulsion, can thus additionally comprise, as additional compound, powders, glitter , coloring agents, especially chosen from water-soluble or non-fat-soluble, organic or inorganic, water-soluble or non-soluble dyes, pigments, optical effect materials, liquid crystals, and mixtures thereof, particulate agents which are insoluble in the fatty phase, emulsifying and / or non-emulsifying silicone elastomers, especially as described in EP 2 353 577, preserving agents, humectants, stabilizers, chelators, emollients, modifying agents chosen from the agents of pH, osmotic force and / or or refractive index modifiers etc. or any usual cosmetic additive, and mixtures thereof.

According to one embodiment, the internal aqueous phase and / or the external aqueous phase comprises at least one coloring agent as defined above. Preferably, the internal aqueous phase of the emulsions according to the invention comprises at least one dye.

The emulsions according to the invention, and in particular the internal aqueous phase and / or the external aqueous phase and / or the fatty phase of the emulsions, can still furthermore comprise at least one active agent, in particular a biological or cosmetic active agent, preferably chosen from hydrating agents, healing agents, depigmenting agents, UV-screening agents, desquamating agents, antioxidants, active agents stimulating the synthesis of dermal macromoleculars and / or epidermal, dermodecontracting agents, antiperspirants, soothing agents, anti-aging agents, perfuming agents and mixtures thereof. Such assets are in particular described in FR 1 558 849.

According to one embodiment, the additional compound (s) and / or active (s), in particular a hydrophilic cosmetic active, added (s) in the internal aqueous phase of an emulsion according to the invention, presents (nt) preferably a LogP less than 1, in particular less than 0.5, better less than 0, even between 0.5 and -2.5, and better still between 0 and -2.5. According to another embodiment, the additional compound (s) and / or active (s), in particular a lipophilic cosmetic active agent, added in the fatty phase of the drops (G1) of an emulsion according to the invention preferably has a LogP greater than 1, in particular greater than 2, more preferably greater than 3, even between 1 and 7, in particular between 1, 5 and 5, and better still between 2 and 3, 5.

The log P (octanol / water partition coefficient of a molecule) gives an estimate of the hydrophobicity of the molecule under consideration and has the advantage of being referenced / tabulated and thus of being easily accessible for most molecules. classics. In addition, the value of the log P (= log (K)) can be evaluated simply by means of molecular modeling software easily accessible on the internet, for example on www.molispiration.com, www. vcclab. org / lab / alogps / start. html ...

An experimental determination is possible by the following method: a precise quantity of the active ingredient is weighed and solubilized in one of the two phases of water or octanol. Two equivalent volumes of the two phases are then contacted with stirring. The concentrations of the active product in each of the two phases are then carried out after thermodynamic equilibrium of the system. This measurement of concentration can for example be carried out by direct measurement of the absorbance, if the molecule absorbs light, or by liquid chromatography. This measurement is carried out for example at 22 ° C.

The coefficient K is then experimentally determined by the ratio of the concentration of the active ingredient in octanol to that in water.

According to one embodiment, an emulsion according to the invention is such that the fatty phase of the drops (G1) further comprises at least one lipophilic active agent (or liposoluble) and the internal aqueous phase further comprises at least one hydrophilic (or water-soluble) active agent.

According to one embodiment, the emulsions of the invention comprise glycerine present in the internal aqueous phase and / or the external aqueous phase. Preferably, the emulsions of the invention comprise at least 5% by weight of glycerin relative to the total weight of said emulsions. Indeed, beyond the texture, the emulsions according to the invention provide another advantage over "conventional" emulsions because they allow the use of glycerin, moreover in high levels.

They may in particular comprise glycerin in a content greater than or equal to 10%, greater than or equal to 20%, greater than or equal to 30%, greater than or equal to 40%, or even up to 50%, by weight, by relative to the total weight of the emulsions.

According to a particular embodiment, an emulsion according to the invention is such that the fatty phase of the drops (G1) further comprises at least one coloring agent (C1) and the internal aqueous phase of the drops (G2) further comprises at least a coloring agent (C2), (C2) being different from (C1), in particular in terms of the color effect. Preferably, the coloring agents (C1) and (C2) are chosen from pigments, nacres, and mixtures thereof.

This embodiment is advantageous in that the color effect obtained during the application of an emulsion according to the invention to a keratinous material is different from that manifested by said emulsion before application. Indeed, before application of the emulsion, and therefore before rupture of the drops (G1) and (G2), the mainly visible color effect, or even the only visible color effect, is that manifested by the drops (G1).

The application of an emulsion according to the invention to a keratin material leads (i) to reveal the color effect of the drops (G2) and thus (ii) to a new and unexpected color effect resulting from the mixing of the coloring agents (C1 ) and (C2).

According to another particular embodiment, an emulsion according to the invention is such that the fatty phase of the drops (G1) further comprises at least one UV filter and the internal aqueous phase of the drops (G2) further comprises at least one active ingredient. , in particular biological or cosmetic, different from the UV filter, and in particular an asset sensitive (or unstable) to solar radiation and more particularly to UV. This embodiment is advantageous in that the presence of UV filters in the fatty phase of the drops (G1) makes it possible to protect the active agent present in the internal aqueous phase of the drops (G2) from the effects of solar radiation and in particular UV radiation. Thus, the integrity of said asset can be preserved over longer periods. This is particularly interesting for solar radiation-sensitive active ingredients, such as, for example, vitamin B, vitamin C, dihydroxyacetone or DHA, EUK 134 (INCI name: Ethylbisiminomethylguaiacol manganese chloride), etc.

Advantageously, when an emulsion according to the invention, in particular the fatty phase of the drops (G1), furthermore comprises at least one perfuming agent, the external aqueous phase, or even the internal aqueous phase, also comprises at least one polymer crosslinked or crosslinked copolymer different from the anionic polymer, in particular different from the carbomer (s) and / or copolymer (s) crosslinked acrylates / C 10-30 alkyl acrylate mentioned above, said crosslinked polymer or crosslinked copolymer comprising at least one unit derived from the polymerization of one of the monomers selected from the group consisting of acrylic acid, methacrylic acid, alkyl acrylate comprising from 1 to 30 atoms.

In the context of the invention, and unless otherwise stated, the term "crosslinked copolymer of methacrylic acid and of alkyl acrylate comprising from 1 to 4 carbon atoms", a crosslinked copolymer resulting from the polymerization of a monomer of methacrylic acid and an alkyl acrylate monomer comprising from 1 to 4 carbon atoms.

According to one embodiment, the crosslinked polymer or the crosslinked copolymer according to the invention, present in the continuous aqueous phase, is chosen from the group consisting of the following polymers or copolymers: Acrylates Copolymer, Acrylates crosspolymer-4, Acrylates crosspolymer-3, Polyacrylate-2 Crosspolymer and Polyacrylate-14 (INCI names).

Among said polymers above, the products sold by LUBRIZOL under the trade names a (INCI name = Polyacrylate-2 Crosspolymer), Fixate Freestyle Polymer (INCI name = Acrylates crosspolymer-3), are most particularly preferred according to the present invention. Carbopol ^® Aqua SF1 (INCI name = Acrylates copolymer) and Carbopol ^® Aqua SF2 (INCI name = Acrylates crosspolymer-4), or that sold by Croda Inc. under the trade name Volarest ™ FL. Preferably, the crosslinked polymer or the crosslinked copolymer is chosen from Carbopol ^® Aqua SF1 (INCI name = Acrylates copolymer) and Carbopol ^® Aqua SF2 (INCI name = Acrylates crosspolymer-4).

According to one embodiment, the crosslinked copolymer is chosen from crosslinked copolymers of acrylic or methacrylic acid and of alkyl acrylates comprising from 1 to 4 carbon atoms.

According to the invention, the emulsion may comprise from 0.1% to 10% by weight, preferably from 0.5% to 8% by weight, and preferably from 1% to 3% by weight of crosslinked polymer (s). (s) or copolymer (s) crosslinked (s) relative to the total weight of said emulsion.

Also, when an emulsion according to the invention, in particular the fatty phase of the drops (G1), further comprises at least one perfuming agent, the external aqueous phase, or even the internal aqueous phase, may further comprise at least one buffer having a pKa of from 4.0 to 9.0, in particular selected from the group consisting of phosphate buffers, 2- (N-morpholino) ethanesulfonic acid, 2-amino-2-hydroxymethyl-1,3 propanediol, 2- (bis (2-hydroxyethyl) amino) acetic acid, 4- (2-hydroxyethyl) -1-piperazine ethane sulfonic acid, sodium citrate and mixtures thereof, preferably 4- (2-hydroxyethyl) -1-piperazine ethane sulfonic acid. Preferably, an emulsion according to the invention comprises from 0.1% to 10% by weight of buffer (s), preferably from 0.5% to 5% by weight, relative to the total weight of said emulsion.

Of course, those skilled in the art will take care to choose any additional compound (s) and / or active (s) mentioned above and / or their respective amounts so that the advantageous properties of the emulsion according to the invention are not or not substantially impaired by the addition envisaged. In particular, the nature and / or the amount of the additional compound (s) and / or active (s) depends (ing) on the aqueous or fatty nature of the phase considered of the emulsion according to the invention . These adjustments are within the skill of the skilled person.

Preparation process

The present invention also relates to a method for preparing an emulsion as defined above, comprising the following steps:

a) contacting an aqueous fluid FE1 and an oily fluid FI;

b) forming a water-in-oil emulsion consisting of drops (G2), formed of the aqueous fluid FE1, dispersed in a fatty phase consisting of the fluid F1, and c) the formation of drops (G1), each drop (G1) consisting of at least one, preferably a single, drop (G2), by contacting the water-in-oil emulsion obtained in step b) with an aqueous fluid FE2;

in which :

the aqueous fluid FE1 comprises at least water and at least one anionic polymer (PA2), in particular a carbomer,

the oily fluid FI comprises at least one oil and / or a suspending agent and at least one cationic polymer (PC), in particular an amodimethicone, and

the aqueous fluid FE2 comprises at least water and at least one anionic polymer (PA1), in particular a carbomer, identical to or different from the anionic polymer (PA2).

According to one embodiment, the above-mentioned steps b) and c) can be simultaneous.

An emulsion according to the invention is preferably obtained by means of a microfluidic process, that is to say by implementation of a microfluidic device, in particular as described in WO 2012/120043.

According to one embodiment, the steps of contacting the fluid FI with the fluid FE1 and the fluid FE2 as defined above may further comprise the presence of an intermediate fluid miscible with the fluid FI, as described in WO 2012/120043. During the step of forming the drops (G1) and / or (G2), this intermediate fluid is therefore present at the interface between the fluid FE1 and the fluid FI and / or at the interface between the fluid FI and the FE2 fluid. This intermediate fluid is intended to form a film around the droplet (G1) and / or (G2) in formation at the level of the microfluidic device. The intermediate fluid differs from the fatty phase of the drops (G1) at least in that it is devoid of the cationic polymer. Thus, the intermediate fluid delays the diffusion of the cationic polymer (PC) present in the fluid FI until the intermediate fluid is mixed with the fluid F1 and thus ensures the formation of very stable drops stabilized by a very thin bark without obstruction of the microfluidic device.

According to another embodiment, a method according to the invention may further comprise a step d) of adding a solution for increasing the viscosity of the external aqueous phase, namely fluid FE2. Preferably, the solution for increasing the viscosity is thus aqueous. This solution for increasing the viscosity is typically added to the aqueous fluid FE2 after the formation of drops (G1) and (G2), step d) therefore being subsequent to step c). According to a mode In one embodiment, the solution for increasing the viscosity comprises a base, especially an alkali hydroxide, such as sodium hydroxide.

According to yet another embodiment, when the oily fluid FI further comprises at least one heat-sensitive suspensive agent as described above, the method for preparing an emulsion according to the invention may require the implementation of at least the fluid FI at a temperature of 40 ° C to 150 ° C.

Thus, according to this embodiment, at least the fluid F1, or even the aqueous fluid FE1, can be heated at a temperature of from 40 ° C. to 150 ° C. for carrying out step a ), or even steps b) and c), and optionally the fluid FE2, may be heated to a temperature of 40 ° C to 150 ° C for carrying out step c).

In the case of the process for preparing an emulsion according to the invention is a microfluidic process, the microfluidic device as such is advantageously heated to a temperature of from 40 ° C to 150 ° C.

Preferably, the heating temperature of the fluid F1, or even the fluids FE1 and FE2, and the microfluidic device is from 50 ° C. to 100 ° C., preferably from 55 ° C. to 90 ° C., in particular 60 ° C. at 80 ° C, and more preferably 65 ° C to 85 ° C.

According to one embodiment, when the oily fluid FI comprises from 5% to 15% by weight of suspending agent (s) thermosensitive (s) relative to the total weight of said oily fluid FI, said oily fluid FI is preferably heated to a temperature of 65 ° C to 70 ° C.

According to one embodiment, when the oily fluid F1 comprises from 15% to 99.99%, preferably from 15% to 40%, by weight of suspending agent (s) heat-sensitive (s) relative to the weight total of said oily fluid FI, said oily fluid F1 is preferably heated to a temperature of 80 ° C to 90 ° C.

Advantageously, the presence of a suspending agent in the oily fluid FI makes it possible to dispense with the use of an intermediate fluid as described in application WO 2012/120043. In this, the process for preparing an emulsion according to the invention is simplified with respect to the preparation process described in WO 2012/120043.

Preferably, the microfluidic device used according to the invention comprises one or more of the following characteristics, taken in any technically possible combination: the outlets of the various ducts (or channels or channels) of the microfluidic device are preferably on the same horizontal axis, so that each drop (G1) and the associated internal drop (G2) are formed simultaneously (in others in other words, the ends of the NF channels and the MF are placed at the same height to generate a single drop-forming step). This embodiment is advantageous in that it makes it possible to control the number of drop (s) (G2) in each drop (G1), and in particular makes it possible to ensure the presence of a single drop (G2) in each droplet. (G1);

when the fatty phase of the drops (G1) is devoid of suspending agent, the microfluidic device advantageously comprises five concentric channels (or channels), as illustrated in Example 1 (the second and fourth channels are dedicated to the flow of intermediate fluids previously described). Alternatively, it is possible that the internal concentric channels do not all share outlets on the same plane. Preferably, the intermediate phases travel in co-flow with the phases of the same nature and the respective outlets are on the same plane;

- At the output of the microfluidic device, the various fluids used form a multi-component drop, according to a hydrodynamic mode called "dripping" (drop-by-drop).

uses

Preferably, an emulsion according to the invention is directly usable, at the end of the aforementioned preparation processes, as a composition, in particular a cosmetic composition. An emulsion according to the invention, when prepared by means of a microfluidic process as described above, can also be used as a composition, in particular a cosmetic composition, in particular after separation of the drops (G1) and redispersion thereof in a second appropriate phase.

The compositions according to the invention can in particular be used in the cosmetics field.

They may comprise, in addition to the aforementioned ingredients, at least one physiologically acceptable medium.

By "physiologically acceptable medium" is meant a medium which is particularly suitable for the application of a composition of the invention to keratin materials, in particular the skin, the lips, the nails, the eyelashes or the eyebrows, and preferably the skin. The physiologically acceptable medium is generally adapted to the nature of the medium to which the composition is to be applied, as well as to the appearance under which the composition is to be packaged.

According to one embodiment, the physiologically acceptable medium is directly represented by the external aqueous phase as described above.

According to one embodiment, the cosmetic compositions are used for the makeup and / or care of keratin materials, especially the skin.

The cosmetic compositions according to the invention may be skincare, sun protection, cleaning (makeup removal), hygiene or make-up products for the skin.

These compositions are therefore intended to be applied especially to the skin.

Thus, the present invention also relates to the non-therapeutic cosmetic use of a cosmetic composition mentioned above, as a makeup, hygiene, cleaning and / or care product for keratinous substances, in particular the skin.

According to one embodiment, the compositions of the invention are in the form of a foundation, a makeup remover, a facial and / or body and / or hair care, anti age, a sunscreen, a oily skin care, a whitening care, a moisturizer, a BB cream, tinted cream or foundation, a face and / or body cleanser , a shower gel or a shampoo.

A care composition according to the invention can be in particular a solar composition, a care cream, a serum or a deodorant.

The compositions according to the invention may be in various forms, in particular in the form of cream, balm, lotion, serum, gel, gel-cream or mist.

The present invention also relates to a non-therapeutic method for the cosmetic treatment of a keratinous material, in particular the skin, comprising at least one step of applying to said keratinous material at least one emulsion or a composition according to the invention.

In particular, the present invention relates to a non-therapeutic method for cosmetic treatment of the skin, comprising a step of applying to the skin at least one emulsion or a composition according to the invention.

The present invention also relates to the use of a water-in-oil-in-water emulsion, comprising an external continuous aqueous phase and, as a dispersed phase, a water-in-oil emulsion in the form of drops (G1). each drop (G1) comprising a continuous fat phase and at least one, preferably a single, drop (G2) comprising an internal aqueous phase, said drops (G1) and (G2) being as defined above, to encapsulate at least a hydrophilic compound, in particular a hydrophilic cosmetic active agent and, optionally, at least one lipophilic compound, in particular a lipophilic cosmetic active agent.

The expressions "between ... and ...", "from ... to ..." and "from ... to ..." must be understood as inclusive, unless otherwise specified.

The amounts of the ingredients in the examples are expressed as percentage by weight relative to the total weight of the emulsion, unless otherwise indicated.

The following examples illustrate the present invention without limiting its scope.

EXAMPLES

EXAMPLE 1 Double emulsion according to the invention without suspensive agent in the fatty phase of drops (G1)

Hereinafter, composition of the external aqueous phase (OF), fatty phase (MF) and internal aqueous phase (IF)

^* : Sufficient quantity for.

Hereinafter, composition of the first and second intermediate fluids:

Hereinafter, composition of the soda solution (BF):

Trade name Supplier INCI name% w / w

Reverse osmosis water

BF

Sodium Hydroxide Pellets PRS Codex PANREAC Sodium Hydroxide 0.42

Total 100,00 The preparation of each of the above phases are within the general skills of those skilled in the art.

The proportions of the different phases of the final emulsion (PF) are presented in the table below.

- Experimental apparatus :

The equipment required for the manufacture of the emulsion according to Example 1 is composed of: 6 syringe pumps (one for OF, MF, IF, first and second intermediate fluids and BF), a microfluidic device (or nozzle) with 5 concentric channels with coaxial outputs with, from the innermost channel to the outermost channel:

- the first lane is dedicated to the passage of the IF;

the second channel is dedicated to the passage of the first intermediate fluid;

- the third way is dedicated to the passage of the MF;

the fourth channel is dedicated to the passage of the second intermediate fluid; and

- the fifth way is dedicated to the passage of the OF.

The second and fourth tracks aim to eliminate the risk of fouling the nozzle by slowing the diffusion of amodimethicone at the water / oil interface between, respectively, (i) the IF and the MF and (ii) ) MF and OF.

The microfluidic device is further adapted to add a soda solution (BF) after formation of the drops (G1) and (G2) and thus enhance the viscosity of the OF.

The flow rates, from the outermost to the innermost channel of the nozzle, are as follows:

OF: 150 ml / hr,

Second intermediate fluid: 2 mIJhr,

- MF: 15.93 mIJhr,

- First intermediate fluid: 2 mIJhr,

IF: 18.13 mL / hr, and

- BF: 9.78 mL / hr. An emulsion according to Example 1 is particularly interesting, on the one hand, in that it ensures a particularly satisfactory encapsulation of hydrophilic compounds through drops (G2) but also lipophilic compounds through drops (G1). In addition, the drops (G1) and (G2) are macroscopic and monodisperse and each drop (G1) comprises a single drop (G2). Thus, the emulsion is endowed with a unique visual. Moreover, the emulsion has a unique texture in the field of double emulsions which, for obvious reasons, responds to a continuous demand from consumers in this direction.

EXAMPLE 2 Double emulsion according to the invention with a heat-sensitive suspending agent in the fatty phase of the drops (G1)

Hereinafter, composition of the external aqueous phase (OF), fat phase (MF) and internal aqueous phase (IF):

% w / w

Phase Business Name Vendor INCI Name

phases

EXTERNAL AQUEOUS GEL PHASE under total 100,00

Reverse osmosis water / Aqua qsp

Microcare PE THOR Phenoxyethanol 0.93

Microcare PTG THOR Pentylenglycol 2,33

Glycerin codex (99%) INTERCHIMI E Glycerin 17,49

EDETA BD BASF Disodium EDTA 0.046

OF Tego carbomer 340 FD EVONIK Carbomer 0,09

Carbopol Ultrez 21 Acrylat.es/C10-30 Alkyl

LUBRIZOL 0,20 Polymer Acrylate Crosspolymer

Zemea propanediol DUPONT TALE AND LYLE Propanediol 5.83

Butylene glycol INTERCHIMI E Butylen glycol 5.83

Sodium Hydroxide

PANREAC Sodium Hydroxide 0.01 Pellets PRS codex

OIL PHASE under total 100,00

DUB ININ Grade A STERAINERI E DUBOIS Isononyl Isononanoate qs

Rheopearl KL2 MYOSHI EUROPE Dextrin palmitate 20,00

Dipentaerythrityl

DUB DPHCC STEARINERI E DUBOIS hexacaprylate / 38,27 hexacaprate

MF Perfume Fragrance 3,24

NUSIL

CAS-3131 Amodimethicone 0, 18

Cl 77891 (Titanium

Dioxide) (and)

Creasperse® White R INNOVATION COMPANY Hydrogenated 1, 00

Polydecene (and)

Hydroxystearic Acid INTERNAL AQUEOUS GEL PHASE totaling 100.00

Reverse osmosis water / Aqua qsp

THOR

Microcare PE Phenoxyethanol 0.93

THOR

Microcare PTG Pentylenglycol 2,33

INTERCHIMI E

Glycerin codex (99%) Glycerin 17,49

BASF

EDETA BD Disodium EDTA 0.04

Evonik

Tego carbomer 340 FD Carbomer 0,09

IF

Carbopol Ultrez 21 LUBRIZOL Acrylat.es/C10-30 Alkyl

0.20 Polymer Acrylate Crosspolymer

DUPONT TATE AND LYLE

Zemea Propanediol Propanediol 5.83

INTERCHIMI E

Butylene glycol Butylen glycol 5.83

Sodium Hydroxide PANREAC

Sodium Hydroxide 0.01 Pellets PRS codex

Synthetic

Sunshine Soft Copper Sun Chemical Fluorphlogopite and Iron 1, 00

Oxides 77491

Hereinafter, composition of the soda solution (BF):

The preparation of each of the above phases are within the general skills of those skilled in the art.

- Experimental apparatus :

The material necessary for the manufacture of the emulsion according to Example 2 is composed of: 4 syringe pumps (one for IF, MF, OF and BF), a syringe heater (for MF), a thermostated bath, a device microfluidic (or nozzle) 3-way concentric with coaxial outputs, from the innermost to the outermost

- the first channel is dedicated to the passage of NF;

- the second lane is dedicated to the passage of the MF; and

- the third way is dedicated to the passage of the OF.

The nozzle and the pipe carrying the oily phase (MF) is placed in a thermostated bath heated to 85 ° C.

The presence of the suspending agent in the fatty phase (MF) makes it possible to dispense with the use of the intermediate fluids described in Example 1, which allows a simplification of the nozzle and therefore of the manufacturing process. Indeed, since the MF has a higher viscosity than the MF of Example 1, it makes it possible to slow the diffusion of the amodimethicone at the water / oil interface between, respectively, (i) NF and the MF and (ii) ) the MF and the OF which makes it possible to prevent the risk of clogging of the nozzle.

The microfluidic device is further adapted to add a soda solution (BF) after formation of the drops (G1) and (G2) to enhance the viscosity of the OF.

The flow rates considered for the different phases are as follows:

OF: 76.70 mIJhr,

- MF: 10,190 mIJhr,

IF: 9.273 mL / hr, and

- BF: 5,000 mL / hr.

An emulsion according to Example 2 is particularly advantageous, on the one hand, in that it ensures a particularly satisfactory encapsulation of hydrophilic compounds thanks to the drops (G2) but also of lipophilic compounds thanks to the drops (G1) and, of On the other hand, it has a unique visual and texture in the field of double emulsions which, for obvious reasons, responds to a continuous demand from consumers for this purpose.

Furthermore, an emulsion according to Example 2 is also particularly interesting in terms of kinetic stability. Moreover, the drops (G1) or (G2) have a higher mechanical strength than those of the emulsion described in Example 1; thus, they remain intact over a time scale greater than 3 months, or even longer than 6 months at 25 ° C.

Alternatively, Rheopearl KL2 (INCI: Dextrin palmitate) can be replaced by Rheopearl MKL2 (INCI: Dextrin Myristate). The oily phase (MF) resulting, and thus the final emulsion obtained, has the advantage of having improved transparency.

Also, the oily phase (MF) may further comprise at least one phenyl silicone oil (for example a phenyltrimethicone, and better still a diphenylsiloxyphenyltrimethicone (INCI: Diphenylsiloxy Phenyl Trimethicone)) which further improves the transparency of the drops (G1) comprising a gelling agent of the Rheopearl KL2 and / or Rheopearl MKL2 type, and thus to improve the transparency of the final composition.

EXAMPLE 3 Double emulsion according to the invention with a thixotropic suspending agent in the fatty phase of the drops (G1)

% w / w

Phase Business Name Vendor INCI Name

phases

EXTERNAL AQUEOUS GEL PHASE under total 100,00

Reverse osmosis water / Aqua qsp

Microcare PE THOR Phenoxyethanol 0.80

Microcare PTG THOR Pentylenglycol 2.00

OF Glycerin codex (99%) INTERCHIMI E Glycerin 20.00

EDETA BD BASF Disodium EDTA 0.04

Tego Carbomer 340 FD EVONIK Carbomer 0.25

Sodium Hydroxide

/ Sodium Hydroxide 0, 1 1 Pellets PRS codex

OIL PHASE under total 100,00

CAPRYLIC CAPRIC

Myritol 318 Friend Chemistry 96.80

TRIGYLCERIDE

MF

SILICA DIMETHYL

Aerosil R974 Azelis 3.00

silylate

CAS-3131 NUSIL Amodimethicone 0,20

INTERNAL AQUEOUS GEL PHASE totaling 100.00

Reverse osmosis water / Aqua qsp

Microcare PE THOR Phenoxyethanol 0.80

Microcare emollient PTG THOR Pentylenglycol 2.00

EDETA BD BASF Glycerin 0.040

IF

Glycerin Codex 99% Interchimie Disodium EDTA 20.00

Carbomer Tego 340FD EVONIK Carbomer 0.25

Acrylat.es/C10-30 Alkyl

Sodium solution 10% / 0, 1 1

Acrylate Crosspolymer

Unicert Blue 05601 -J

Sensient Cl 42090 0.45 0.1% The preparation of each of the phases are within the general skills of those skilled in the art.

The proportions of the different phases in the final emulsion (PF) are presented in the table below.

Experimental apparatus:

The equipment necessary for the manufacture of the emulsion of Example 3 is composed of: 3 syringe pumps (one for each phase), a microfluidic device (or nozzle) with concentric 3-way ports with coaxial outlets with, from the channel more internal to the outermost path,:

- the first lane is dedicated to the passage of the IF;

- the second lane is dedicated to the passage of the MF; and

- the third way is dedicated to the passage of the OF.

As in Example 2, the presence of the suspending agent in the fat phase (MF) makes it possible to dispense with the use of the intermediate fluids described in Example 1, which allows a simplification of the nozzle and therefore of the manufacturing process. .

The flow rates considered for the different phases are the following: - OF: 120 ml_ / hr,

MF: 15 ml / hr, and

IF: 5 mL / hr.

An emulsion according to Example 3 is particularly advantageous, on the one hand, in that it ensures a particularly satisfactory encapsulation of hydrophilic compounds thanks to the drops (G2) but also of lipophilic compounds thanks to the drops (G1) and, of On the other hand, it has a unique visual and texture in the field of double emulsions which, for obvious reasons, responds to a continuous demand from consumers for this purpose.

Furthermore, an emulsion according to Example 3 is also particularly interesting in terms of kinetic stability, since the drops (G1) or (G2) have a higher mechanical strength than those of the emulsion described in Example 1; thus, they remain intact on a time scale greater than 3 months, or even longer than 6 months, at 25 ° C.

Claims

A water-in-oil-in-water emulsion, comprising an external continuous aqueous phase and a water-in-oil emulsion in the form of drops (G1), each drop (G1) comprising a continuous fat phase and at least one, preferably a single drop (G2) comprising an internal aqueous phase,

said drops (G2) comprising a bark formed of at least one anionic polymer (PA2), identical to or different from (PA1), and at least one cationic polymer (PC).

2. Emulsion according to claim 1, wherein the fatty phase of the drops (G1) comprises at least one oil selected from the group consisting of hydrocarbon oils of vegetable origin, hydrocarbon oils of animal origin, esters and synthetic ethers. linear or branched hydrocarbons of mineral or synthetic origin, silicone oils, fatty alcohols having from 8 to 26 carbon atoms, partially hydrocarbon and / or silicone fluorinated oils and mixtures thereof, preferably esters and synthetic ethers.

An emulsion according to any of claims 1 or 2 comprising from 0% to 99.99%, preferably from 5% to 99.49%, in particular from 20% to 90%, more preferably from 30% to 80%. %, or even 50% to 70%, by weight of oil (s) relative to the total weight of the fatty phase of the drops (G1).

4. Emulsion according to any one of claims 1 to 3, wherein the anionic polymers (PA1) and (PA2), identical or different, are polymers comprising monomeric units comprising at least one carboxylic acid function, preferably are chosen from carbomers and crosslinked copolymers of acrylates / C _{_10-3} o alkyl acrylate.

5. Emulsion according to any one of claims 1 to 4, comprising from 0.01% to 5%, preferably from 0.05% to 2%, and more preferably from 0.1% to 0.5%, by weight. of anionic polymer (s) (PA1) and (PA2), in particular carbomer (s), relative to the total weight of said emulsion.

6. Emulsion according to any one of claims 1 to 5, wherein the cationic polymer (PC) has the following formula (I):

(I) in which:

- Ri, R ₂ and R ₃ , independently of each other, represent OH or CH ₃ ;

x is an integer from 10 to 5000;

y is an integer between 2 and 1000; and

z is an integer between 0 and 10.

7. Emulsion according to any one of claims 1 to 6, comprising from 0.01% to 10%, preferably from 0.05% to 5%, by weight of cationic polymer (s) (PC), in particular amodimethicone (s), relative to the total weight of the fatty phase of the drops (G1).

8. Emulsion according to any one of claims 1 to 7, wherein the fatty phase of the drops (G1) further comprises at least one suspending agent, preferably selected from organic or inorganic, polymeric or molecular lipophilic suspending agents, the solid fatty substances at room temperature and pressure, and mixtures thereof.

The emulsion of claim 8, wherein the suspending agent is selected from the group consisting of polyacrylates; sugar / polysaccharide esters and fatty acid (s), in particular esters of dextrin and fatty acid (s), esters of inulin and fatty acid (s) or esters of glycerol and of 'Fatty acids ; polyamides; and mixtures thereof, preferably the dextrin and fatty acid esters, in particular selected from the group consisting of dextrin palmitates, dextrin myristates, dextrin palmitates / ethylhexanoates, and mixtures thereof.

10. Emulsion according to claim 8, in which the suspending agent is chosen from the group consisting of optionally modified clays, silicas, such as fumed silica optionally treated with hydrophobic surfaces, and mixtures thereof, preferably optionally fumed silica. Hydrophobic treated surface.

11. Emulsion according to any one of claims 8 to 10, comprising from 0% to 99.99%, preferably from 0.5% to 70%, in particular from 1% to 50%, better still from 2% to 40%. %, in particular from 2.5% to 30%, and preferably from 10% to 20% by weight of suspensive agent (s) relative to the total weight of the fatty phase of the drops (G1).

12. Emulsion according to any one of claims 1 to 1 1, wherein the volume fraction p (IF / (IF + MF)) is between 0.1 and 0.7, preferably between 0.3 and 0, 6, and more preferably between 0.4 and 0.5, where:

IF represents the total volume of the drops (G2), and

MF represents the total volume of the drops (G1).

13. Emulsion according to any one of claims 1 to 12, wherein the internal aqueous phase of the drops (G2) comprises at least one additional compound and / or an active ingredient, in particular a hydrophilic cosmetic active, preferably having a log P less than 1, in particular less than 0.5, better still less than 0, even between 0.5 and -2.5, and better still between 0 and -2.5.

14. Emulsion according to any one of claims 1 to 13, further comprising at least one active agent selected from hydrating agents, healing agents, depigmenting agents, UV filters, desquamating agents, antioxidants, stimulating active agents. the synthesis of dermal and / or epidermal macromolecular agents, dermodecontracting agents, antiperspirants, soothing agents, anti-aging agents, perfuming agents and mixtures thereof.

15. Emulsion according to any one of claims 1 to 14, wherein the size of the drops (G1) is greater than 500 μηι, or even greater than 1,000 μηι, and better is between 500 μηι and 3,000 μηι, preferably between 1,000 μηι and 2,000 μηι, in particular between 800 μηι and 1,500 μηι and / or the size of drops (G2) is greater than 10 μηι, or even greater than 50 μηι, and better is between 10 μηι and 2,000 μηι, in particular between 50 μηι and 1,500 μηι, better between 100 μηι and 1,100 μηι, preferably between 200 μηι. μηι and 800 μηι, and better between 300 μηι and 700 μπι.

16. Emulsion according to any one of claims 1 to 15, said emulsion not comprising surfactant.

17. Process for the preparation of an emulsion according to any one of claims 1 to 16, comprising the following steps:

a) contacting an aqueous fluid FE1 and an oily fluid FI;

b) forming a water-in-oil emulsion consisting of drops (G2), formed of the aqueous fluid FE1, dispersed in a fatty phase consisting of the fluid F1, and

c) the formation of drops (G1), each drop (G1) consisting of at least one, preferably a single, drop (G2), by contacting the water-in-oil emulsion obtained in step b) with an aqueous fluid FE2;

in which :

the oily fluid FI comprises at least one oil and / or at least one suspending agent and at least one cationic polymer (PC), in particular an amodimethicone, and

18. Process according to claim 17, in which at least the fluid F1, or even the aqueous fluid FE1, is / are heated at a temperature of between 40 ° C. and 150 ° C. for carrying out step a) or even steps b) and c), and optionally the fluid FE2, is heated to a temperature of 40 ° C to 150 ° C for carrying out step c).

19. Composition, in particular cosmetic, comprising at least one emulsion according to any one of claims 1 to 16 and a physiologically acceptable medium.

20. Non-therapeutic method for cosmetic treatment of a keratinous material, in particular the skin, comprising at least one step of applying to said keratinous material at least one emulsion according to any one of claims 1 to 16 or at least one composition according to claim 19.

21. Use of a water-in-oil-in-water emulsion, comprising an external continuous aqueous phase and a water-in-oil emulsion in the form of drops (G1), each drop (G1) comprising a continuous fatty phase and at least one, preferably a single, drop (G2) comprising an internal aqueous phase, said drops (G1) and (G2) being as defined in any one of claims 1 to 16, for encapsulating at least one hydrophilic compound , in particular a hydrophilic cosmetic active agent and, optionally, at least one lipophilic compound, in particular a lipophilic cosmetic active agent.