FR3110405A1 - Double stable emulsion without bark - Google Patents

Abstract

The present invention relates to a water-in-oil-in-water emulsion, comprising an external continuous aqueous phase, preferably in the form of a gel, and, as a dispersed phase, a water-in-oil emulsion in the form of drops ( G1), each drop (G1) comprising a continuous fatty phase comprising at least one lipophilic gelling agent and at least one drop (G2) comprising an internal aqueous phase, in which: - the fatty phase has a melting point of between 50 ° C and 100 ° C, preferably between 60 ° C and 90 ° C, and, at room temperature and atmospheric pressure, meets the following physicochemical criteria: - a hardness (x) of between 2 and 14 N, preferably between 2.5 and 12 N, better still between 3 and 9 N, and very particularly between 4 and 6 N; and - A tack (y) greater than or equal to -2 N, better still greater than or equal to -1 N, and in particular greater than or equal to -0.6 N; and - the emulsion does not include amodimethicone. Figure for the abstract: None

Description

Double stable emulsion without bark

The subject of the present invention is stable water-in-oil-in-water double emulsions comprising an aqueous continuous phase and drops (G1), in particular macroscopic drops of a gelled fatty phase, in which the drops (G1) comprise at least a drop (G2), in particular macroscopic, of an internal aqueous phase. It also relates to their method of preparation as well as their use in compositions, in particular cosmetics.

Interest in compound encapsulation continues to grow. Indeed, encapsulation technologies concern a wide variety of industrial sectors such as medicine, pharmacy, food or cosmetics. Encapsulating a compound, for example hydrophilic, such as a cosmetic active principle, consists in isolating it from the external environment. This strategy is particularly necessary when this compound is incompatible with other elements of the aqueous phase and/or sensitive to the external environment. Water-in-oil-in-water double emulsions are particularly interesting because they allow the simultaneous encapsulation of hydrophilic and lipophilic compounds in different compartments.

Several methods have been developed to best adapt to different applications such as spray-drying or the coacervation method. In particular, there currently exist stable double emulsions of macroscopic drops of a fatty phase dispersed in an aqueous continuous phase, the drops of fatty phase comprising drops of a dispersed aqueous phase, in particular described in applications WO2018077986 and WO2018077977 . These emulsions are obtained using a microfluidic process and their kinetic stability is ensured thanks to the presence of a shell deriving from a complex interfacial coacervation reaction which is based in particular on a lipophilic silicone cationic polymer, amodimethicone.

There is an increasingly strong demand from consumers for compositions, in particular cosmetics, devoid of silicone compounds because of their environmental impact, since they are not biodegradable, and/or their suspected danger to health. Furthermore, the inventors have observed that the presence of amodimethicone can sometimes lead to problems of compatibility with other raw materials and/or phenomena of aggregation of the drops between them, adhesion of the drops to the packaging and/or defects in the sphericity of the drops, which for obvious reasons is not desirable. Indeed, such drawbacks can impact the stability of the emulsion and/or the homogeneity of delivery of the different constituent phases of the emulsion and/or the visual and aesthetic rendering of the emulsion, or even its sensoriality on application. on the skin, and these disadvantages are exacerbated as the diameter of the drops increases. Without wishing to be bound by any theory, the Applicant believes that the aforementioned defect in the sphericity of the drops may be linked to a reduction in the elastic character of the dispersed fatty phase due to the presence of amodimethicone.

There is therefore a need for new water-in-oil-in-water double emulsions comprising drops, in particular macroscopic drops, which remain satisfactory in terms of kinetic stability and therefore of visual and aesthetic rendering, and of ease of application on the skin, despite the absence of amodimethicone and therefore of bark.

More particularly, the present invention aims to provide a double emulsion, in particular macroscopic, endowed with satisfactory encapsulation properties combined with satisfactory kinetic stability and ease of application and therefore particularly attractive for the consumer.

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

- the fatty phase has a melting point of between 50°C and 100°C, preferably between 60°C and 90°C, and, at room temperature and atmospheric pressure, meets the following physicochemical criteria:
- a hardness (x) of between 2 and 14 N, preferably between 2.5 and 12 N, better still between 3 and 9 N, and very particularly between 4 and 6 N; And
- a tackiness (y) greater than or equal to -2 N, better still greater than or equal to -1 N, and in particular greater than or equal to -0.6 N; And
- the emulsion does not include amodimethicone.

Preferably, the fatty phase of the drops (G1) of an emulsion according to the invention also has a cohesion (z) less than or equal to 40, preferably less than or equal to 35, and better still less than or equal to 30.

An emulsion according to the invention therefore comprises at least:
- an internal aqueous phase in the form of drop(s) (G2), which can also be designated by the terms “dispersed aqueous phase” or “IF”,
- a continuous fatty phase in the form of drop(s) (G1), which can also be designated by the term “intermediate fatty phase”, “fatty phase”, “intermediate phase”, “oily phase” or “MF”, and
- a continuous aqueous phase, which can also be designated by the terms “external aqueous phase”, “external continuous aqueous phase”, “external phase” or “OF”.

As emerges from the examples below, and unexpectedly, the implementation of a continuous fatty phase endowed with the above physicochemical properties makes it possible to obtain emulsions, in particular macroscopic, endowed with satisfactory or even improved performance, in terms of kinetic stability and therefore visual and aesthetic rendering, and ease of application on the skin, despite the absence of amodimethicone and therefore of bark.

In particular, the inventors have observed that an emulsion according to the invention has satisfactory or even improved performance in terms of non-aggregation of the drops (G1) with each other, non-adhesion of the drops (G1) to the packaging, and in terms of comfort and ease of application on the skin.

Given the absence of amodimethicone, an emulsion according to the invention also allows more freedom with regard to the compounds and/or their contents, in particular of active ingredients, which can be encapsulated, in particular in the fatty phase.

An emulsion according to the invention is therefore particularly interesting, 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), while being endowed with satisfactory properties in terms of kinetic stability and ease of application on the skin, despite the absence of amodimethicone and therefore of bark, which makes them unprecedented double emulsions.

Despite the absence of amodimethicone and therefore of bark, an emulsion according to the invention, and in particular the drops (G1) or (G2), remain intact over a time scale greater than 1 week, or even greater than 1 month , and even longer than 3 months, at ambient 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 were stable at ambient temperature, for example T=25°C ± 2°C, and at ambient pressure, for example 1013 mbar, given the absence of amodimethicone and therefore of bark.

By "stable" or "kinetic stability" is meant, within the meaning of the present invention, at ambient temperature and atmospheric pressure, the absence of creaming or sedimentation of the drops (G1) of fatty phase in the continuous aqueous phase, the absence of creaming or sedimentation of the drops (G2) of internal aqueous phase in the associated fatty phase, the absence of opacification of the continuous aqueous phase and/or of the fatty phase and/or of the internal aqueous phase, the absence of aggregation of the drops (G1) with each other and of the drops (G2) with each other, and in particular the absence of coalescence or Oswald ripening of the drops (G1) with each other and of the drops (G2) with each other , the absence of adhesion of the drops (G1) to the packaging and the absence of leakage of materials (i) from the fatty phase towards the continuous aqueous phase, or conversely, (ii) from the fatty phase towards the internal aqueous phase , or vice versa and (iii) from the internal aqueous phase to the continuous aqueous phase, or vice versa ent, and this over a period of time greater than or equal to 1 month, preferably greater than or equal to 3 months, and better still greater than or equal to 6 months.

By "gelling agent" is meant, within the meaning of the present invention, an agent making it possible to increase the viscosity of the phase devoid of said gelling agent, and preferably to achieve a final viscosity of the phase thus gelled greater than 20 000 mPa.s, preferably greater than 50,000 mPa.s, better still greater than 100,000 mPa.s, and very particularly greater than 200,000 mPa.s.

Preferably, in an emulsion according to the invention, the drops (G1), or even the drops (G2), are macroscopic, that is to say visible to the naked eye.

By "macroscopic" or "macroscopic drop" or "macroscopic emulsion" is meant, within the meaning of the present invention, drops (G1), or even drops (G2), visible to the naked eye, as opposed to to microscopic drops not visible to the naked eye.

Thus, preferably, in an emulsion according to the invention:
- the drops (G1) having a diameter greater than or equal to 400 μm, preferably greater than or equal to 600 μm, better still greater than or equal to 800 μm, in particular greater than or equal to 1000 μm, or even greater than or equal to 1500 μm, represent a volume greater than or equal to 60%, or even greater than or equal to 70%, preferably greater than or equal to 80%, and better still greater than or equal to 90% of the total volume of the continuous fatty phase; and or
- at least 60%, or even at least 70%, preferably at least 80%, and better still at least 90%, of the drops (G1) have an average diameter greater than or equal to 400 μm, preferably greater than or equal to 600 μm , better still greater than or equal to 800 μm, in particular greater than or equal to 1000 μm, or even greater than or equal to 1500 μm;
and or
- drops (G2) having a diameter greater than or equal to 50 μm, preferably greater than or equal to 80 μm, in particular greater than or equal to 100 μm, or even greater than or equal to 150 μm, and better still greater than or equal to 200 μm , represent a volume greater than or equal to 60%, or even greater than or equal to 70%, preferably greater than or equal to 80%, and better still greater than or equal to 90% of the total volume of the internal aqueous phase; and or
- at least 60%, or even at least 70%, preferably at least 80%, and better still at least 90%, of the drops (G2) have an average diameter greater than or equal to 50 μm.

Determining the volume of drops having a particular diameter relative to the total volume of the dispersed phase falls within the general knowledge of those skilled in the art, in particular with regard to the method for measuring the diameter described below.

In particular, the size of the drops (G1) is greater than 500 μm, or even greater than 1000 μm, and better still is between 500 μm and 3000 μm, preferably between 1000 μm and 2000 μm, in particular between 800 μm and 1500 µm.

In the context of the present invention, the term “size” designates the diameter, in particular the average diameter, of the drops.

In the context of the present invention, the aforementioned emulsions can also be designated by the term "dispersions". With regard to the nature of the phases of an emulsion of the water-in-oil-in-water type according to the invention, the continuous fatty phase is immiscible with the continuous aqueous phase and the internal aqueous phase at ambient temperature and atmospheric pressure. . Thus, the solubility of the continuous fatty phase in the continuous aqueous phase and the internal aqueous phase is advantageously less than 5% by weight, and vice versa.

An emulsion according to the invention can be qualified as a macroscopically inhomogeneous mixture of at least two immiscible phases, in particular when the drops (G1), or even the drops (G2), are macroscopic. In other words, in an emulsion according to the invention, each of the phases can be individualized, in particular with the naked eye.

According to another embodiment, an emulsion according to the invention does not comprise a surfactant.

According to one embodiment, an emulsion according to the invention does not comprise glyceryl trioctanoate, glycerol tricaprylate/caprate, and their mixture.

According to another embodiment, an emulsion according to the invention does not comprise:
- dextrin ester and fatty acid(s), and in particular dextrin palmitate(s), and/or silica optionally treated with hydrophobicity, for example fumed silica, and/or
- Acrylates/C10-30 Alkyl Acrylate Crosspolymer, in particular Pemulen™ EZ-4U Polymeric Emulsifier from Lubrizol; and or
- Cetyl Ethylhexanoate.

Preferably, the drops (G1), or even the drops (G2), advantageously have an apparent monodispersity (i.e. they are perceived by the eye as spheres identical in diameter).

The drops (G1), or even the drops (G2), are advantageously substantially spherical.

The drops (G1) and (G2) of an emulsion according to the invention are devoid of shell or membrane, in particular of polymeric membrane or membrane formed by interfacial polymerization. In particular, drops (G1) and (G2) are not stabilized using a coacervate membrane (anionic polymer (carbomer)/cationic polymer (amodimethicone) type). In other words, the contact between the aqueous continuous phase and the continuous fatty phase on the one hand and between the internal aqueous phase and the continuous fatty phase on the other hand is direct.

Thus, according to one embodiment, an emulsion according to the invention does not comprise a bark, in particular a bark formed of a layer of coacervate interposed between the fatty phase and the external and internal aqueous phase.

In particular, an emulsion according to the invention does not comprise (is devoid of) lipophilic cationic polymer corresponding to the following formula:

in which :
- R1, R2 and R3, independently of each other, represent OH or CH3;
- R4 represents a group -CH2- or a group -X-NH- in which X is a divalent alkylene radical in C3 or C4;
- x is an integer between 10 and 5000, preferably between 30 and 1000, and better still between 80 and 300;
- y is an integer between 1 and 1000, in particular between 2 and 1000, preferably between 4 and 100, and better still between 5 and 20; And
- z is an integer between 0 and 10, preferably between 0 and 1, and better still is equal to 1.

The drops (G1), or even the drops (G2), differ from solid capsules, that is to say capsules equipped with a solid shell (or “membrane”), such as for example those described in WO 2010/ 063937, and capsules provided with an evanescent bark, such as for example those described in WO2018077986 and WO2018077977.

Furthermore, the microfluidic process implemented to manufacture an emulsion according to the invention makes it possible to form macroscopic drops (G1) and (G2) with at least monodisperse drops (G1), or even drops (G2). In addition, the microfluidic process allows perfect control of the contents of each phase implemented, and therefore of the concentrations of the encapsulated active ingredients.

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 for example to the field of medicine, pharmacy, agriculture, nutrition or (agro)-food.

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

Temperature and pressure

Unless otherwise indicated, in what follows, we consider that we are at ambient temperature (for example T=25°C ± 2°C) and atmospheric pressure (760 mm Hg, i.e. 1.013.10 ⁵ Pa or 10 ¹³ mbar).

Viscosity

The viscosity of an emulsion according to the invention or of at least one of its phases can vary significantly, which makes it possible to obtain varied textures. The viscosity is measured at ambient temperature and at ambient pressure according to the method described in WO2017046305.

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 100 000 mPa.s, and more particularly from 1,000 mPa.s to 30,000 mPa.s, as measured at 25° C. according to the method described above.

External continuous aqueous phase

As indicated above, an emulsion according to the invention comprises an external continuous aqueous phase, preferably in the form of a gel, in particular a gel having a viscosity suitable for suspending the drops (G1) and thus contributing to the kinetic stability and the attractive visual of an emulsion according to the invention. Indeed, a good suspension of the drops (G1) makes it possible to prevent/reduce unwanted phenomena such as the coalescence of the drops (G1) between them and/or the adhesion of the drops (G1) to the internal walls of the packaging and/or creaming or sedimentation of the drops (G1), likely to alter the appearance of the emulsion and the homogeneity of delivery of the different constituent phases of the emulsion.

Advantageously, the continuous aqueous phase is not solid at ambient temperature and at ambient pressure, that is to say that it is capable of flowing under its own weight.

According to one embodiment, the continuous aqueous phase has a viscosity of between 400 mPa.s and 100,000 mPa.s, preferably between 800 mPa.s and 30,000 mPa.s, as measured at 25° C. according to the method described above.

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

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

According to one embodiment, the mass 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%, in particular 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 external continuous aqueous phase of the emulsion according to the invention may also 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 continuous aqueous phase contributes in particular to enhancing 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 chosen from the group consisting of alkali metal hydroxides and alkaline-earth metal hydroxides.

Preferably, the mineral base is an alkali metal hydroxide, and in particular 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 even 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 preferentially from 0.02% to 1% by weight of base, preferably from mineral base, and in particular NaOH, relative to the total weight of said emulsion.

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 consists of a continuous fatty phase comprising at least one drop (G2) formed of a dispersed aqueous phase (also called internal aqueous phase).

According to one embodiment, an emulsion according to the invention is obtained by a microfluidic process as defined below. Therefore, the drops (G1) have a uniform size distribution. Preferably, the fatty phase of the emulsions of the invention consists of a population of monodispersed drops (G1), in particular such that they have an average diameter ranging from 500 µm to 3000 µm and a coefficient of variation Cv of less than 10%, or even less than 3%.

In the context of the present description, the term "monodispersed drops" means the fact that the population of drops of the dispersed phase according to the invention has a uniform size distribution. Monodisperse drops exhibit good monodispersity. Conversely, drops with poor monodispersity are said to be "polydispersed".

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

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

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

From these values D _i , 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 _i of the drops of the emulsion around the mean diameter .

Knowing the mean diameter and the standard deviation σ of an emulsion, one can determine that one finds 95.4% of the population of drops in the interval of diameters and that we find 68.2% of the population in the interval .

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

This parameter reflects the distribution of the diameters of the drops as a function of the average diameter of the latter.

The coefficient of variation Cv of the diameters of the drops (G1) according to this embodiment of the invention is less than 10%, preferably less than 5%, or even less than 3%.

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

Continuous fatty phase

The continuous fatty phase of an emulsion according to the invention has a melting point of between 50°C and 100°C, preferably between 60°C and 90°C.

The melting point of a fatty phase can be measured using a differential scanning calorimeter (DSC), for example the calorimeter sold under the name "DSC Q2000" by the company TA Instruments. The sample preparation and measurement protocols are as follows: a 5 mg sample of the sample to be tested, previously heated to 80°C and taken with magnetic stirring using a spatula, which is also heated, is placed in an aluminum thermal 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 flushed with nitrogen. Cooling is provided by the RCS 90 heat exchanger. The sample is then subjected to the following protocol by first being brought to temperature at 20°C, then subjected to a first temperature rise ranging from 20°C to 130 °C, at a heating rate of 5°C/minute, then is cooled from 130°C to -80°C at a cooling rate of 5°C/minute and finally subjected to a second temperature rise ranging from - 80°C to 130°C at a heating rate of 5°C/minute. During the second rise in temperature, the variation of the difference in power absorbed by the empty crucible and by the crucible containing the sample is measured as a function of the temperature. The melting point of the compound is the temperature value corresponding to the apex of the peak of the curve representing the variation of the difference in power absorbed as a function of temperature. The melting end temperature corresponds to the temperature at which 95% of the sample has melted.

The continuous fatty phase of an emulsion according to the invention must satisfy at least the following two physicochemical criteria of hardness and stickiness:
- a hardness (x) of between 2 N and 14 N, preferably between 2.5 N and 12 N, in particular between 3 and 9 N, and better still between 4 and 6 N. The hardness (or firmness )) corresponds to the maximum compression force measured in Newtons divided by the surface of the texturometer cylinder expressed in mm2 in contact with the tested sample. Related to an emulsion according to the invention, the hardness (x) is an indicator of the sensory rendering of an emulsion on application to a keratin material, in particular the skin. On the one hand, the hardness must not be too low to guarantee the drops (G1) of continuous fatty phase sufficient mechanical resistance, in particular to shearing and/or to mechanical stresses linked for example to the manufacture and packaging of the emulsion and/or its transport, and thus guarantee satisfactory kinetic stability to the emulsion, in particular in the presence of non-airless packaging. On the other hand, the hardness must not be too high so as not to degrade the sensoriality, in particular the comfort and the ease of application of the emulsion on application to the skin. The above is exacerbated the greater the diameter of the drops (G1) of continuous fatty phase.
- a stickiness (y) greater than or equal to -2 N, better still greater than or equal to -1 N, and in particular greater than or equal to -0.6 N. The stickiness (or adhesion (adhesiveness)) represents the work necessary to overcoming the attractive forces between the surface of the product and the material with which it is in contact (for example, the total force necessary to separate the measuring tool from the sample). Related to an emulsion according to the invention, the stickiness criterion (y) is an indicator of the kinetic stability of the emulsion with regard to the phenomena of adhesion of the drops (G1) to the wall of the packaging.

Advantageously, the continuous fatty phase of an emulsion according to the invention also has a cohesion (z) less than or equal to 40, preferably less than or equal to 35, and better still less than or equal to 30. Preferably, the fatty phase advantageously has a cohesion (z) greater than or equal to 15, preferably greater than or equal to 20, and better still greater than or equal to 25. Advantageously, the continuous fatty phase has a cohesion (z) of between 15 and 40, preferably between 20 and 35, and better between 20 and 30. Cohesiveness corresponds to the way in which the tested product resists the second deformation, relative to the way it behaved during the first deformation. The cohesion corresponds to the surface of the second curve (Area. 2) on the surface of the first curve (Area 1) (ie Area. 2/ Area. 1). In other words, cohesion represents the forces within the tested sample. Thus, strong bonds within the gel will allow a completely reversible deformation during the first compression which will induce a force A2 identical to the force A1, and therefore 100% cohesion. Consequently, the stronger the cohesion, the more the gel is deformable. The lower the cohesion, the more brittle the gel (weak bonds, no resistance to stress). Related to an emulsion according to the invention, the cohesion criterion (z) is an indicator of the kinetic stability of the emulsion with regard to the phenomena of aggregation, or even coalescence, of the drops (G1) between them. Cohesion corresponds to the property of the drops (G1) to stick to themselves. Thus, a minimum of cohesion is needed to ensure the “gelled” character of the drops (G1) but not too much to prevent the gelled drops (G1) from sticking together.

The hardness, adhesion and cohesion measurements are obtained using the shimadzu EZ-X texturometer and the texturometer protocol described below:
- the sample to be tested is placed in a mold 40 mm in diameter filled to 75% of its height.
- The mobile used is a cylindrical acrylic mobile 12.7 mm in diameter. Moving the mobile involves 4 steps:
1) a 1st step after automatic detection of the sample surface where the mobile moves at the measurement speed of 1 mm/s, and penetrates the sample at a penetration depth of 5 mm, the software notes the value of the maximum force reached;
2) a 2nd so-called withdrawal step, at a speed of 1 mm/s, where the mobile returns to its initial position and rises by more than 5 mm; and the energy of withdrawal of the probe (negative force) is noted;
3) a 3rd step repeating the same action 1) described above; And
4) a 4th step repeating the same action 2) described above.

This combination of physicochemical criteria constitutes a non-obvious compromise characterizing an anhydrous gel that is brittle but not very sticky and not very elastic. As emerges from the examples below, this combination of physicochemical criteria makes it possible to access emulsions, in particular macroscopic ones, endowed with satisfactory or even improved performance, in terms of kinetic stability, and therefore of visual and aesthetic rendering, and of sensoriality. , in particular comfort and ease of application on the skin, despite the absence of amodimethicone and therefore of bark.

The drops (G1) of continuous fatty phase preferably rest on a viscoelastic gel with an elastic modulus greater than the viscous modulus. The drops (G1) do not flow under their own weight, but can be easily deformed by pressure, for example with a finger. Thus, their consistency is close to that of butter, with a malleable and prehensible character. The drops (G1) can be spread easily by hand, in particular on a keratin material, in particular the skin.

The continuous fatty phase preferably has a viscosity suitable for suspending the drops (G2) and thus contributing to the kinetic stability and the attractive visual appearance of an emulsion according to the invention. Indeed, a good suspension of the drops (G2) makes it possible to prevent/reduce unwanted phenomena such as the coalescence of the drops (G2) between them and/or the creaming or the sedimentation of the drops (G2).

The continuous fatty phase of an emulsion according to the invention comprises at least one lipophilic gelling agent. It is essentially the combination between at least one lipophilic gelling agent and at least one oily solvent which allows the dispersed fatty phase of an emulsion according to the invention to satisfy the physicochemical criteria x and y, even z, mentioned above.

Lipophilic gelling agent

The presence of at least one lipophilic gelling agent in the fatty phase of the drops (G1) contributes in particular to (i) suspending the drop(s) (G2) within each drop (G1) and (ii) to reinforcing the mechanical resistance of the drops (G1) and therefore the kinetic stability of an emulsion according to the invention. Thus, the drops (G1) and (G2) can remain intact over 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.

Advantageously, a lipophilic gelling agent is a heat-sensitive gelling agent, namely which reacts to heat, and in particular is a gelling agent which is solid at room temperature and liquid at a temperature above 50° C., preferably above 60° C., and better above 70°C. Preferably, a heat-sensitive lipophilic gelling agent according to the invention has a melting point of between 50°C and 130°C, and preferably between 60°C and 120°C.

The lipophilic gelling agent according to the invention can be chosen from organic or mineral, polymeric or molecular lipophilic gelling agents; fatty substances that are solid at ambient temperature and pressure; and their mixtures.

Organic or inorganic, polymeric or molecular lipophilic gelling agent(s)

As inorganic lipophilic gelling agent, mention may be made of optionally modified clays such as hectorites modified with a C ₁₀ to C ₂₂ ammonium chloride, such as hectorite modified with di-stearyl di-methyl ammonium chloride such as, for example , that marketed under the name of Bentone 38V0 by the company ELEMENTIS. Mention may also be made of hectorite modified with distearyldimethylammonium chloride, also known as quaternium-18 bentonite, such as the products marketed or manufactured under the names Bentone 34 by the company Rheox, Claytone XL, Claytone 34 and Claytone 40 marketed or manufactured by the company Southern Clay, the modified clays known under the name of benzalkonium and quaternium-18 bentonites and marketed or manufactured under the names Claytone HT, Claytone GR and Claytone PS by the company Southern Clay, the clays modified by chloride of stearyldimethylbenzoylammonium, known as steralkonium bentonites, such as the products marketed or manufactured under the names Claytone APA and Claytone AF by the company Southern Clay, and Baragel 24 marketed or manufactured by the company Rheox.

Mention may also be made of fumed silica optionally treated hydrophobic at the surface, the size of the particles of which is less than 1 μm. It is in fact possible to chemically modify the surface of the silica, by chemical reaction generating a reduction in the number of silanol groups present on the surface of the silica. It is possible in particular to substitute silanol groups with hydrophobic groups: a hydrophobic silica is then obtained.

The hydrophobic groups can be:
- trimethylsiloxyl groups, which are obtained in particular by treating fumed silica in the presence of hexamethyldisilazane. Silicas thus treated are called “Silica silylate” according to the CTFA ( ^8th edition, 2000). They are for example marketed under the references Aerosil R812Ò by the company DEGUSSA, CAB-O-SIL TS-530Ò by the company CABOT; Or
- dimethylsilyloxyl or polydimethylsiloxane groups, which are obtained in particular by treating fumed silica in the presence of polydimethylsiloxane or dimethyldichlorosilane. Silicas thus treated are called “Silica dimethyl silylate” according to the CTFA ( ^8th edition, 2000). They are for example marketed under the references Aerosil R972Ò, and Aerosil R974Ò by the company DEGUSSA, CAB-O-SIL TS-610Ò and CAB-O-SIL TS-720Ò by the company CABOT.

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

Polymeric organic lipophilic gelling agents are, for example, partially or totally crosslinked elastomeric organopolysiloxanes, of three-dimensional structure, such as those marketed under the names KSG6Ò, KSG16Ò and KSG18Ò by the company SHIN-ETSU, Dow Corning® EL-7040, Trefil E-505CÒ and Trefil E-506CÒ by DOW-CORNING, Gransil SR-CYCÒ, SR DMF10Ò, SR-DC556Ò, SR 5CYC gelÒ, SR DMF 10 gelÒ and SR DC 556 gelÒ by GRANT INDUSTRIES, SF 1204Ò and JK 113Ò by GENERAL ELECTRIC; ethylcellulose such as that sold under the name Ethocel® by the company DOW CHEMICAL; galactommanans comprising from one to six, and in particular from two to four, hydroxyl groups per ose, substituted by a saturated or unsaturated alkyl chain, such as guar gum alkylated by C ₁ to C ₆ alkyl chains, and in particular C ₁ to C ₃ and mixtures thereof. Block copolymers of the “diblock”, “triblock” or “radial” type of the polystyrene/polyisoprene, polystyrene/polybutadiene type such as those marketed under the name Luvitol ^HSB® by the company BASF, of the polystyrene/copoly(ethylene-propylene) type such as those marketed under the name ^Kraton® by the company SHELL CHEMICAL CO or else of the polystyrene/copoly(ethylene-butylene) type, mixtures of triblock and radial (star) copolymers in isododecane such as those marketed by the company PENRECO under the name ^Versagel® such as for example the mixture of butylene/ethylene/styrene triblock copolymer and of ethylene/propylene/styrene star copolymer in isododecane (Versagel M 5960).

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

As lipophilic gelling agent, mention may also be made of polymers with an average molecular mass by weight of less than 100,000, comprising a) a polymeric backbone having hydrocarbon repeating units provided with at least one heteroatom, and optionally b) at least one fatty chain pendant and/or at least one optionally functionalized terminal fatty chain, having from 6 to 120 carbon atoms and being linked to these hydrocarbon units, as described in applications WO 02/056847, WO 02/47619, in particular the resins of polyamides (in particular comprising alkyl groups having from 12 to 22 carbon atoms) such as those described in US 5,783,657.

As an example of a polyamide resin that can be implemented according to the present invention, mention may be made of UNICLEAR 100 ^VG® marketed by the company ARIZONA CHEMICAL.

It is also possible to use silicone polyamides of the polyorganosiloxane type such as those described in US 5,874,069, US 5,919,441, US 6,051,216 and US 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 ramifications.

Among the lipophilic gelling agents which 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 mono- or poly-ester of dextrin and of at least one fatty acid corresponding to the following formula (II):

(II)

• n est un nombre entier allant de 2 à 200, de préférence allant de 20 à 150, et en particulier allant de 25 à 50,
  • les radicaux R_4,R₅et R_6,identiques ou différents, sont choisis parmi l'hydrogène ou un groupement acyle -COR_adans lequel le radical R_areprésente un radical hydrocarboné, linéaire ou ramifié, saturé ou insaturé, possédant de 5 à 50, de préférence de 5 à 25 atomes de carbone,

sous réserve qu'au moins un desdits radicaux R₄, R₅ou R₆est différent de l'hydrogène.in which :

• n is an integer ranging from 2 to 200, preferably ranging from 20 to 150, and in particular ranging 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 from 5 to 25 carbon atoms,

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

Among the esters of dextrin and of 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 esters of dextrin and fatty acid(s) marketed under the names Rheopearl® KL2 or D2 (INCI name: dextrin palmitate), Rheopearl® TT2 (INCI name: dextrin palmitate ethylhexanoate), and Rheopearl® MKL2 ( INCI name: dextrin myristate) by the company 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 of fatty acid(s) marketed under the names Rheopearl® ISK2 or Rheopearl® ISL2 (INCI name: Stearoyl Inulin) by the company Miyoshi Europe.

Among the lipophilic gelling agents that can be used, mention may also be made of the polyacrylates resulting from the polymerization of C ₁₀ -C ₃₀ alkyl acrylate(s), preferably of C ₁₄ -alkyl acrylate(s). C _24, and even more preferably C ₁₈ -C ₂₂ alkyl acrylate(s). According to one embodiment, the polyacrylates are polymers of acrylic acid esterified with a fatty alcohol whose saturated carbon chain comprises 10 to 30 carbon atoms, preferably 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, mention may more particularly be made of stearyl polyacrylate and behenyl polyacrylate. Preferably, the gelling agent is polystearyl acrylate or polybehenyl acrylate. Mention may in particular be made of the polyacrylates marketed 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.

Among the lipophilic gelling agents which can be used, mention may be made of esters of glycerol and of fatty acid(s), in particular a mono-, di- or triester of glycerol and of fatty acid(s). Typically, said ester of glycerol and fatty acid(s) can 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 chosen 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):

(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. Mention may in particular be made of the esters of glycerol and 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 company Nisshin Oillio.

Solid fatty substances

The fatty substance that is solid at ambient temperature and pressure is chosen in particular from the group consisting of waxes, pasty fatty substances, butters and mixtures thereof.

Raincoats)

By "wax" is meant within the meaning of the invention, a lipophilic compound, solid at room temperature (25 ° C), 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 previously. The waxes capable of being used in an emulsion according to the invention can be chosen from waxes which are solid, deformable or not at ambient temperature, of animal, vegetable, mineral or synthetic origin and mixtures thereof. It is in particular possible to use hydrocarbon waxes such as beeswax, lanolin wax, and China insect waxes; Rice Wax, Carnauba Wax, Candelilla Wax, Ouricurry Wax, Alfa Wax, Cork Fiber Wax, Sugar Cane Wax, Japan Wax and Sumac Wax ; montan wax, microcrystalline waxes, paraffins and ozokerite; polyethylene waxes, waxes obtained by the Fisher-Tropsch synthesis and waxy copolymers as well as their esters. Mention may in particular be made 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 CFPA, Performa®260 (INCI name: Synthetic wax) and Performa®103 (INCI name: Synthetic wax) by 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 the waxes obtained by catalytic hydrogenation of animal or vegetable oils having linear or branched C ₈ -C ₃₂ fatty chains.

Among these, mention may in particular be made of hydrogenated jojoba oil, hydrogenated sunflower oil, hydrogenated castor oil, hydrogenated coconut oil and hydrogenated lanolin oil, di-( trimethylol-1,1,1 propane) sold under the name "HEST 2T-4S" by the company HETERENE, the tetrabehenate of di-(trimethylol-1,1,1 propane) sold under the name HEST 2T-4B by the company HETERENE. It is also possible to use the waxes obtained by transesterification and hydrogenation of vegetable oils, such as castor oil or olive oil, such as the waxes sold under the names of Phytowax ricin ^16L64® and ^22L73® and Phytowax Olive 18L57 by the company SOPHIM. Such waxes are described in application FR 2 792 190. It is also possible to use silicone waxes which can advantageously be substituted polysiloxanes, preferably with 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 176-1118-3 and 176-11481 (GENERAL ELECTRIC ). The silicone waxes that can be used can 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 ₂₀ -C ₆₀ ) alkyldimethicones , in particular (C ₃₀ -C ₄₅ )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 from Koster Keunen. The waxes can also be chosen from fluorinated waxes.

Butter(s) or pasty fat

By “butter” (also called “pasty fatty substance”) within the meaning of the present invention, is meant a lipophilic fatty compound with a reversible solid/liquid state change and comprising at a 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 can be lower than 25°C. The liquid fraction of the pasty compound measured at 25° C. can represent from 9% to 97% by weight of the compound. This liquid fraction at 25° C. preferably represents between 15% and 85%, more preferably between 40% and 85% by weight. Preferably, the butter(s) have an end-of-melting temperature of less than 60°C. Preferably, the butter(s) have a hardness less than or equal to 6 MPa. Preferably, the butters or pasty fatty substances present in the solid state an anisotropic crystalline organization, visible by X-ray observations. Within the meaning of the invention, the melting temperature corresponds to the temperature of the most endothermic peak observed in analysis (DSC) as described in ISO 11357-3; 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 . Regarding the measurement of the melting temperature and the determination of the end of melting temperature, the sample preparation and measurement protocols are as described in WO2017046305. The liquid fraction by weight of butter (or pasty fatty substance) at 25°C is equal to the ratio of the melting enthalpy consumed at 25°C to the melting enthalpy of the butter. The melting enthalpy of butter or pasty compound is the enthalpy consumed by the compound to pass from the solid state to the liquid state. Butter is said to be in the solid state when all of its mass is in solid crystalline form. Butter is said to be in a liquid state when all of its mass is in liquid form. The melting enthalpy of butter is equal to the integral of the entire melting curve obtained using the aforementioned calorimeter, with a temperature rise of 5°C or 10°C per minute, depending on the standard ISO 11357-3:1999. Butter's enthalpy of melting is the amount of energy required to change the compound from solid to liquid. It is expressed in J/g. The enthalpy of fusion consumed at 25°C is the quantity of energy absorbed by the sample to pass from the solid state to the state it presents 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 equal to 100%, the temperature at the end of the melting range of the pasty compound is less than or equal to 32°C. The liquid fraction of butter measured at 32°C is equal to the ratio of the enthalpy of melting consumed at 32°C to the enthalpy of melting of butter. The enthalpy of fusion consumed at 32°C is calculated in the same way as the enthalpy of fusion consumed at 23°C.

Regarding the measurement of hardness, the sample preparation and measurement protocols are as described in WO2017046305.

The pasty fatty substance or butter can be chosen from synthetic compounds and compounds of vegetable origin. A pasty fatty substance can be obtained by synthesis from starting products 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 lanolins,
- polymeric or non-polymeric silicone compounds such as polydimethylsiloxanes of high molecular masses, polydimethylsiloxanes with side chains of the alkyl or alkoxy type having from 8 to 24 carbon atoms, in particular stearyl dimethicones,
- polymeric or non-polymer fluorinated compounds,
- vinyl polymers, in particular
- olefin homopolymers,
- olefin copolymers,
- 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 copolymer oligomers of vinyl esters having C ₈ -C ₃₀ alkyl groups,
- oligomers homo and copolymers of vinylethers having C ₈ -C ₃₀ alkyl groups,
- liposoluble polyethers resulting from the polyetherification between one or more C ₂ -C ₁₀₀ , preferably C ₂ -C ₅₀ , diols,
- esters and polyesters, and
- their mixtures.

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

Mention may more particularly be made of C10-C18 triglycerides (INCI name: C10-18 Triglycerides) comprising, 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 (Kpangnan) butter ( Pentadesma butyracea ), Coffee butter ( Coffea arabica ), Apricot butter ( Prunus Armeniaca ) , Macadamia butter ( Macadamia Temifolia ), l grapeseed butter ( 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 hydrogenated jojoba oil (INCI name: Jojoba esters) and shea butter ethyl esters (INCI name: Shea butter ethyl esters), and mixtures thereof.

Preferably, the lipophilic gelling agent is chosen from Castor Oil/IPDI Copolymer (and) Caprylic/Capric Triglyceride, in particular marketed under the name Estogel M by PolymerExpert, Caprylic/Capric Triglyceride (and) Polyurethane-79, in particular marketed under the name OILKEMIA™ 5S polymer by the company Lubrizol, Trihydroxystearin, in particular marketed under the name THIXCIN® R by the company Elementis Specialties, and mixtures thereof, and better still Castor Oil/IPDI Copolymer (and) Caprylic/Capric Triglyceride.

According to a 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 as marketed by NuSil Technology under the name CareSil ™ CXG-1104 (INCI: Dimethicone (and) Dimethicone/Vinyl Dimethicone Crosspolymer).

Preferably, the viscosity of the fatty phase of the drops (G1) of an emulsion according to the invention is between 20,000 and 100,000,000 mPa.s, preferably between 50,000 and 1,000,000 mPa.s, and better between 100,000 to 500,000 mPa.s, at 25°C.

Those skilled in the art will take care to choose the lipophilic gelling agent(s) and/or their quantity so as to satisfy the melting points and physicochemical properties x and y, or even z, of the phase aforementioned fat. In particular, the nature and/or the quantity of lipophilic gelling agent(s) must take into account the process implemented (in particular of the “non-microfluidic” or “microfluidic” type) for the manufacture of the emulsion according to the invention. These adjustments fall within the competence of a person skilled in the art with regard to the teaching of this description.

In particular, an emulsion according to the invention may comprise from 0.5% to 25%, preferably from 1% to 20%, in particular from 1.5% to 15%, and better still from 2% to 10%, in weight of lipophilic gelling agent(s) relative to the total weight of the continuous fatty phase of the drops (G1). These percentages therefore refer to the lipophilic gelling agent(s) only present in the dispersed fatty phase.

Preferably, the content of lipophilic gelling agent(s) is greater than or equal to 2%, preferably greater than or equal to 5%, and better still greater than or equal to 8% by weight, relative to the weight total of the continuous fatty phase of the drops (G1).

Oils)

According to one embodiment, the continuous fatty phase of the drops (G1) can comprise at least one oil.

The term “oil” is understood to mean a fatty substance that is liquid at ambient temperature (25° C.).

As oils that can be used in the emulsion of the invention, mention may be made, for example:
- hydrocarbon oils of plant origin, in particular as described below;
- hydrocarbon oils of animal origin, such as perhydrosqualene and squalane;
- synthetic esters and ethers, in particular of fatty acids, such as the oils of formulas R ₁ COOR ₂ and R ₁ OR ₂ in which R ₁ represents the residue of a C ₈ to C ₂₉ fatty acid, and R ₂ represents a hydrocarbon chain, branched or not, C ₃ to C ₃₀ , such as 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, octylhydroxystearate, octyldodecyl hydroxystearate, diisostearyl malate, triisocetyl citrate, heptanoates, octanoates, decanoates of fatty alcohols; polyol esters, such as propylene glycol dioctanoate, neopentyl glycol diheptanoate and diethylene glycol diisononanoate; and pentaerythritol esters such as pentaerythrityl tetrabehenate (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, such as for example polymethylsiloxanes (PDMS) volatile or not with a linear or cyclic silicone chain, liquid or pasty at room temperature, in particular cyclopolydimethylsiloxanes (cyclomethicones) such as cyclohexasiloxane and cyclopentasiloxane; polydimethylsiloxanes (or dimethicones) comprising alkyl, alkoxy or phenyl groups, pendent or at the end of the silicone chain, groups having from 2 to 24 carbon atoms; phenyl silicones such as phenyltrimethicones, phenyldimethicones, phenyltrimethylsiloxydiphenyl-siloxanes, diphenyl-dimethicones, diphenylmethyldiphenyl trisiloxanes, 2-phenylethyltrimethyl-siloxysilicates, and polymethylphenylsiloxanes;
- fatty alcohols having from 8 to 26 carbon atoms, such as cetyl alcohol, stearyl alcohol and their mixture (cetylstearyl alcohol), or even octyldodecanol;
- partially hydrocarbon and/or silicone fluorinated oils such as those described in document JP-A-2-295912;
- and mixtures thereof.

Preferably, the continuous fatty phase comprises at least one vegetable oil.

As hydrocarbon oil(s) of plant origin, mention may be made of caprylic and capric acid triglycerides, caprylic and capric acid triglycerides (also known as "MCT oil"), myristic and stearic (INCI name: Caprylic/capric/myristic/stearic Triglyceride), triethylhexanoin, meadowfoam seed oil Limnanthes Alba (INCI name: Limnanthes Alba (Meadowfoam) Seed Oil), macadamia nut oil ( INCI name: Macadamia Ternifolia Seed Oil), Rosa Canina Rosehip Oil (INCI name: Rosa Canina Fruit Oil), Soybean Oil (INCI name: Glycine Soja (Soybean) Oil), Sunflower Seed Oil (INCI name: Helianthus Annuus (Sunflower) Seed Oil), Tribehenin (INCI name: tribehenin), Triisostearin (INCI name: triisostearin), Apricot Kernel Oil (INCI name: Prunus Armeniaca (Apricot) Kernel Oil), rice bran oil (INCI name: Oryza Sativa (Rice) Bran Oil), argan oil (INCI name: Argania Spinosa Kernel Oil), avocado oil (INCI name: Persea Gratissima Oil), evening primrose oil (INCI name: Oenothera Biennis Oil), rice germ oil (INCI name: Oryza Sativa Germ Oil), walnut oil hydrogenated coconut oil (INCI name: Hydrogenated Coconut Oil), sweet almond oil (INCI name: Prunus Amygdalus Dulcis Oil), sesame seed oil (INCI name: Sesamum Indicum Seed Oil), rapeseed oil (INCI name: Hydrogenated Rapeseed Oil), safflower seed oil (INCI name: Carthamus Tinctorius Seed Oil), Queensland nut oil Macadamia integrifolia (INCI name: Macadamia Integrifolia Seed Oil), tricaprylin (or triacylglycerol), wheat germ oil (INCI name: Triticum Vulgare Germ Oil), borage seed oil (INCI name: Borago Officinalis Seed Oil), shea oil (INCI name: Butyrospermum Parkii Oil) , hydrogenated castor oil (INCI name: Hydrogenated Castor Oil), Chinese cabbage seed oil (INCI name: Brassica Campestris Seed Oil), camellia oil, e t in particular Japanese camellia seed (INCI name: Camellia Japonica Seed Oil), green tea seed oil (INCI name: Camellia Sinensis Seed Oil), sea buckthorn oil (INCI name: Hippophae Rhamnoides Oil) , Camellia Kissi seed oil (INCI name: Camellia Kissi Seed Oil), Moringa seed oil (INCI name: Moringa Pterygosperma Seed Oil), canola oil (INCI name: Canola Oil), l Tea Seed Oil (INCI name: Camellia Oleifera Seed Oil), Carrot Seed Oil (INCI name: Daucus Carota Sativa Seed Oil), Triheptanoine (INCI name: Triheptanoin), Vanilla Oil (INCI name: Triheptanoin), INCI: Vanilla Planifolia Fruit Oil), Canola Oil and Phytosterol Glycerides (INCI name: Phytosteryl Canola Glycerides), Blackcurrant Seed Oil (INCI name: Ribes Nigrum (Black Currant) Seed Oil), karanja seed oil (INCI name: Pongamia Glabra Seed Oil), achiote oil (INCI name: Achiote (Bixa orellana) Oil), and mixtures thereof.

Preferably, the oil is chosen from vegetable oils rich in polyunsaturated fatty acids. The term "unsaturated fatty acid" within the meaning of the present invention, a fatty acid comprising at least one double bond. According to a preferred embodiment, unsaturated fatty acids comprising from 18 to 22 carbon atoms are used as oil, in particular polyunsaturated fatty acids, in particular ω-3 and ω-6 fatty acids.

Advantageously, the fatty phase comprises at least one oil having a refractive index close to that of the aqueous continuous phase, namely an oil having a refractive index, at room temperature and atmospheric pressure, preferably between 1.2 and 1 .6, preferably between 1.25 and 1.5, in particular between 1.3 and 1.4. This embodiment is advantageous in that it makes it possible to improve the transparency of the fatty phase, and therefore the transparency of the emulsion according to the invention. Transparency can be qualified according to the method described in WO2018/167309. Advantageously, the oil having a refractive index of between 1.2 and 1.6 is a silicone oil, in particular a phenyl silicone oil.

Advantageously, the fatty phase of an emulsion according to the invention comprises at least one, or even at least two, hydrocarbon oil(s) of vegetable origin, preferably chosen from among seed oil of meadowfoam Limnanthes Alba (INCI name: Limnanthes Alba (Meadowfoam) Seed Oil, triglycerides of caprylic and capric acids, and mixtures thereof.

Preferably, the oil which may be present in the fatty phase of an emulsion according to the invention is not a silicone oil or a fluorinated oil. Preferably, an emulsion according to the invention, in particular the dispersed fatty phase, does not comprise polydimethylsiloxane (PDMS or dimethicone) or one of its derivatives, and preferably does not comprise silicone oil, and in particular octamethylcyclotetrasiloxane (or Cyclotetrasiloxane or D4), decamethylcyclopentasiloxane (or Cyclopentasiloxane or D5) and cyclohexasiloxane (or D6).

The person skilled in the art will take care to choose the oil/oils and/or their quantity so as to satisfy the melting points and the physicochemical properties x and y, even z, of the fatty phase mentioned above. These adjustments fall within the competence of a person skilled in the art with regard to the teaching of this description.

An emulsion according to the invention may comprise between 0% and 99.5%, preferably between 5% and 95%, in particular between 20% and 90%, better still between 30% and 80%, or even between 50% and 70% , by weight of oil(s) relative to the total weight of the continuous fatty phase of the drops (G1).

An emulsion according to the invention may comprise from 1% to 50%, preferably from 5% to 40%, and better still from 10% to 25%, by weight of oil(s) relative to the total weight of said emulsion.

An emulsion according to the invention is also advantageous in that its kinetic stability allows high percentages of continuous fatty phase and therefore of drops (G1). Thus, an emulsion according to the invention may comprise from 0.1% to 70%, preferably from 0.5% to 65%, in particular from 1% to 60%, or even from 3% to 50%, preferably from 5% to 40%, better still from 10% to 30%, and in particular from 15% to 20%, by weight of continuous fatty phase, and therefore of drops (G1), relative to the total weight of the emulsion.

Drops (G2)

As indicated above, each drop (G1) comprises at least one drop (G2) comprising the internal aqueous phase. Preferably, each drop (G1) comprises at least two, preferably at least five, and in particular at least 10, drop (G2) comprising the internal aqueous phase.

Preferably, each drop (G1) comprises the same number of drop(s) (G2).

Preferably, the drops (G2) do not flow under their own weight, but can be easily deformed by pressure, for example with a finger, including in the presence of a hydrophilic gelling agent as described below.

For obvious reasons, for a given population of drops (G1), the size (or diameter) of the drops (G1) is necessarily greater than the size (or diameter) of the associated drop(s) (G2) ).

In particular, the size of the drops (G2) is greater than 50 μm, or even greater than 80 μm, and better still is between 50 μm and 2000 μm, in particular between 80 μm and 1500 μm, better still between 100 μm and 1 100 μm, in particular between 200 μm and 800 μm, and better still between 300 μm and 700 μm.

In particular, an emulsion according to the invention comprises from 0.1% to 50%, preferably from 1% to 40%, in particular from 2.5% to 30%, and better still from 5% to 20%, by weight of internal aqueous phase, and therefore of drops (G2), relative to the total weight of the continuous fatty phase, and therefore of drops (G1).

• IF représente le volume total des gouttes (G2), et
• MF représente le volume total des gouttes (G1) (et donc sans le volume total des gouttes (G2)).

According to one embodiment, in the emulsions according to the invention, the volume fraction ρ (IF/(IF+MF) is between 0.1 and 0.7, preferably between 0.3 and 0.6, and better still between 0.4 and 0.5, where:

• IF represents the total volume of drops (G2), and
• MF represents the total volume of drops (G1) (and therefore without the total volume of drops (G2)).

According to one embodiment, and as indicated above, an emulsion according to the invention is obtained by a microfluidic process as defined below. Consequently, the drops (G2) advantageously have a uniform size distribution. Preferably, the internal aqueous phase of the emulsions of the invention consists of a population of monodispersed drops (G2), in particular such that they have an average diameter ranging from 50 μm to 2000 μm and a coefficient of variation Cv of less than 10%, or even less than 3%, measured according to the methods described above.

Preferably, the drops (G1) and (G2) are respectively monodispersed drops as defined above.

According to a particular embodiment, the internal aqueous phase of the drops (G2) of an emulsion according to the invention can be a gaseous phase. Thus, the internal phase of such drops (G2) comprises at least one gas, for example chosen from air, oxygen, nitrogen, nitrous oxides, rare gases, carbon dioxide, and mixtures thereof.

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

The term "raw materials" is intended to denote any type of compound capable of being used in the fatty phase of the drops (G1) and the internal aqueous phase of the drops (G2), for example oils, gelling agents, texture agents, the active agents and the additional compounds described in the present description.

Internal aqueous phase

As indicated above, the drops (G2) according to the invention comprise an internal aqueous phase, identical to or different, preferably different, from the continuous aqueous phase described above.

Advantageously, the internal aqueous phase is not solid at ambient temperature and at ambient pressure, that is to say that it is capable of flowing under its own weight.

According to one embodiment, the internal aqueous phase has a viscosity of between 0 mPa.s and 10,000 mPa.s, 10,000 mPa.s, preferably between 0 mPa.s and 2,000 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.

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

According to one embodiment, the mass 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 %, in particular 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 can be in the form of an oil-in-water emulsion, identical or different, 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 μm, preferably less than 400 μm, in particular less than 300 μm, better still less than 200 μm, in particular less than 100 μm, or even less than 20 μm, and better still less than 10 μm. Preferably, the size of the drops (G3) is between 0.1 and 200 μm, preferably between 0.25 and 100 μm, in particular between 0.5 μm and 50 μm, preferably between 1 μm and 20 μm, and better between 1 μm and 10 μm, or even between 3 μm and 5 μm.

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

Advantageously, the drops (G3) and/or (G4) are not macroscopic, and are therefore microscopic, 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 (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 make it possible to have an effect on the texture. Indeed, an emulsion according to the invention comprising such finely dispersed drops (G3) and/or (G4) exhibits even improved smoothness qualities.

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

Additional compound(s)

An emulsion according to the invention, and in particular the internal aqueous phase and/or the external aqueous phase and/or the fatty phase, may/may also comprise at least one additional compound different from the lipophilic gelling agent and the oils mentioned above. (e)s.

An emulsion according to the invention, and in particular the internal aqueous phase and/or the external aqueous phase and/or the continuous fatty phase of said emulsion, can thus also further comprise powders as an additional compound; charges ; Glitter ; coloring agents, chosen in particular from water-soluble or non-water-soluble, fat-soluble or not, organic or inorganic coloring agents, materials with an optical effect, liquid crystals, and mixtures thereof; particulate agents insoluble in the fatty phase; curators; humectants; perfuming agents, in particular as defined in WO2019002308; stabilizers; chelators; emollients; modifying agents chosen from gelling/texture, viscosity, in particular hydrophilic agents such as those described below, different from the base and the lipophilic gelling agents mentioned above, pH, osmotic strength and/or refractive index etc… or any usual cosmetic additive; and their mixtures.

By "filler" is meant in the sense of the invention colorless or white particles, solids of any shape, which are in an insoluble form and dispersed in the middle of the composition. Of mineral or organic nature, they make it possible to confer body or rigidity and/or softness, and uniformity to the deposit, in particular in a make-up context, and improved stability with regard to exudation and the properties non-migration after application and/or dullness and/or coverage.

By “particulate agents insoluble in the fatty phase”, is meant within the meaning of the invention the group consisting of pigments, ceramics, polymers, in particular acrylic polymers, and mixtures thereof.

The emulsions according to the invention and in particular the internal aqueous phase and/or the external aqueous phase and/or the continuous fatty phase of the emulsions, may further comprise at least one active ingredient, in particular biological or cosmetic, preferably chosen from moisturizing agents, healing agents, depigmenting agents, UV filters, desquamating agents, antioxidant agents, active agents stimulating the synthesis of dermal and/or epidermal macromoleculars, dermo-contracting agents, antiperspirant agents, soothing agents, anti-aging agents, perfuming agents and mixtures thereof. Such active agents are described in particular in FR 1 558 849.

Hydrophilic gelling agent(s)

Advantageously, an emulsion according to the invention, in particular the external aqueous phase and/or the internal aqueous phase, can also comprise at least one hydrophilic gelling agent different from the oils and lipophilic gelling agents described above.

In the context of the present invention, the term "hydrophilic gelling agent" may be designated interchangeably by the term "hydrophilic texture agent". The hydrophilic gelling agent makes it possible to modulate the fluidity of the emulsion, and therefore the sensorial and/or galenic quality, which it is desired to obtain and/or contribute to further improving the kinetic stability of the emulsion, in particular by preventing/preventing the phenomena of transfer of compounds from the internal aqueous phase to the continuous aqueous phase, or vice versa.

• les agents gélifiant naturels, notamment choisis parmi les extraits d'algues, les exsudats de plantes, les extraits de graines, les exsudats de microorganismes, tel que l’alcasealan (INCI : Alcaligenes Polysaccharides), et autres agents naturels, en particulier l’acide hyaluronique,
• les agents gélifiant semi-synthétiques, notamment choisis parmi les dérivés de la cellulose et les amidons modifiés,
• les agents gélifiant synthétiques, notamment choisis parmi les homopolymères d'acide (méth)acrylique ou un de leurs esters, les copolymères d'acide (méth)acrylique ou un de leurs esters, les copolymères d'AMPS (2-acrylamido-2-méthylpropane sulfoniques acide), les polymères associatifs,
• les autres agents gélifiant, notamment choisis parmi les glycols, les polyéthylèneglycols (commercialisé sous la dénomination Carbowax), les argiles, les silices telles que celles commercialisées sous les dénominations Aérosil® 90/130/150/200/300/380), en particulier la glycérine, le propylène glycol, le butylène glycol, le penthylène glycol, le propanediol, le méthylpropanediol, l’hexanediol, et
• leurs mélanges.

As hydrophilic gelling agents, that is to say soluble or dispersible in water, and therefore able to 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 those cited in FR3041251, and in particular:

• natural gelling agents, chosen in particular from seaweed extracts, plant exudates, seed extracts, microorganism exudates, such as alcasealan (INCI: Alcaligenes Polysaccharides), and other natural agents, in particular hyaluronic acid,
• semi-synthetic gelling agents, chosen in particular from cellulose derivatives and modified starches,
• synthetic gelling agents, chosen in particular 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- methylpropane sulfonic acid), associative polymers,
• other gelling agents, in particular chosen from glycols, polyethylene glycols (marketed under the name Carbowax), clays, silicas such as those marketed under the names Aérosil® 90/130/150/200/300/380), in particular glycerin, propylene glycol, butylene glycol, penthylene glycol, propanediol, methylpropanediol, hexanediol, and
• their mixtures.

By “associative polymer” within the meaning of the present invention, is meant any amphiphilic polymer comprising in its structure at least one fatty chain and at least one hydrophilic portion; the associative polymers in accordance with the present invention can be anionic, cationic, nonionic or amphoteric; these are in particular those described in FR 2 999 921. Preferably, they are amphiphilic and anionic associative polymers and amphiphilic and nonionic associative polymers as described below.

Preferably, the aqueous continuous phase and/or the internal aqueous phase comprises at least one hydrophilic gelling agent chosen from Carbomer, alcasealan (INCI: Alcaligenes Polysaccharides), agar-agar and mixtures thereof.

Preferably, the aqueous continuous phase and/or the internal aqueous phase comprises at least one hydrophilic gelling agent chosen from natural texture agents, in particular seaweed extracts such as agar-agar, carrageenans, alginates, and mixtures thereof, and preferably agar-agar.

Advantageously, a hydrophilic gelling agent, in particular when present in the internal aqueous phase, is a heat-sensitive gelling agent, namely which reacts to heat, and in particular is a gelling agent which is solid at room temperature and liquid at a temperature above 50° C. , preferably greater than 60°C, and better still greater than 70°C. Preferably, a heat-sensitive hydrophilic gelling agent according to the invention has a melting point of between 50° C. and 130° C., and preferably between 60° C. and 120° C., and advantageously chosen from agar-agar. The presence of a heat-sensitive hydrophilic gelling agent in the internal aqueous phase advantageously makes it possible to prevent the phenomena of coalescence of the drops (G2) with each other and/or migration of compounds present in the internal aqueous phase towards the external aqueous phase, or Conversely.

In particular, the internal aqueous phase and the external aqueous phase of an emulsion according to the invention differ by the nature and/or the content of hydrophilic gelling agent(s).

Advantageously, an emulsion according to the invention comprises from 0.0001% to 20%, preferably from 0.001% to 15%, in particular from 0.01% to 10%, and better still from 0.1% to 5%, in weight of hydrophilic gelling agent(s) relative to the total weight of the aqueous phase comprising it(s).

According to a preferred embodiment, the internal aqueous phase and/or the external aqueous phase comprises at least one additional and/or active compound, in particular a hydrophilic cosmetic active ingredient, which has a LogP of less than 1, in particular less than 0.5 , better still less than 0, or 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 ingredient(s), in particular a lipophilic cosmetic active ingredient, added in the continuous 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, better still greater than 3, or even between 1 and 7, in particular between 1.5 and 5, and better still between 2 and 3 ,5.

The log P (known as the octanol/water partition coefficient of a molecule) gives an estimate of the hydrophobicity of the molecule considered and has the advantage of being referenced/tabulated and therefore of being easily accessible for most molecules classics. In addition, the value of the log P (= log (K)) can be evaluated simply thanks to molecular modeling software easily accessible on the internet such as for example on www.molispiration.com, www.vcclab.org/lab/a logps /start.html.

An experimental determination is possible by the following method: a precise quantity of the active ingredient is weighed and it is dissolved in one of the two phases of water or octanol. Two equivalent volumes of the 2 phases are then brought into contact 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 concentration measurement 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 determined experimentally by the ratio of the concentration of the active ingredient in the octanol to that in the water.

According to a preferred embodiment, an emulsion according to the invention is such that the continuous fatty phase of the drops (G1) comprises at least one lipophilic (or fat-soluble) active ingredient and the internal aqueous phase comprises at least one hydrophilic (or water-soluble) active ingredient. , preferably endowed with the aforementioned Log P values.

According to one embodiment, the internal aqueous phase and/or the external aqueous phase of an emulsion according to the invention also comprises glycerin. 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 compared to “conventional” emulsions because they make it possible to use glycerin, which is moreover in high contents.

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 continuous 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 one 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 keratin material is different from that exhibited by said emulsion before application. Indeed, before application of the emulsion, and therefore before breaking up of the drops (G1) and (G2), the predominantly 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 on a keratin material leads (i) to revealing the color effect of the drops (G2) and therefore (ii) to a new and unexpected color effect resulting from the mixture of coloring agents (C1 ) and (C2).

According to another particular embodiment, an emulsion according to the invention is such that the continuous 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, in particular biological or cosmetic, different from the UV filter, and in particular an active 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 ingredient present in the internal aqueous phase of the drops (G2) from the effects of solar radiation and in particular UV. Thus, the integrity of said asset can be preserved over even longer times. This is particularly interesting for active ingredients sensitive to solar radiation, such as vitamins B, vitamin C, dihydroxyacetone or DHA, EUK 134 (INCI name: Ethylbisiminomethylguaiacol manganese chloride), etc.

Also, when an emulsion according to the invention, in particular the continuous fatty phase of the drops (G1), additionally comprises at least one perfuming agent, the external aqueous phase and/or the internal aqueous phase, little(ven)t in further comprising at least one buffer having a pKa of 4.0 to 9.0, in particular selected from the group consisting of phosphate buffers, 2-(N-morpholino)ethane sulfonic 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 the possible additional compound(s) and/or active ingredient(s), in particular the hydrophilic gelling agent(s), mentioned above and/or their respective amounts in such a way that the advantageous properties of the emulsion according to the invention are not or substantially not altered by the addition envisaged. In particular, the nature and/or the quantity of the additional and/or active compound(s) depend(s) on the aqueous or fatty nature of the phase considered of the emulsion according to the invention. . Also, the nature and / or the amount of additional compound (s) and / or active (s), in particular in gelling agent (s) hydrophilic (s), must take into account the process implemented (in particular of the “non-microfluidic” or “microfluidic” type) for the manufacture of the emulsion according to the invention. These adjustments fall within the competence of a person skilled in the art.

Preparation process

An emulsion according to the invention can be prepared by various processes.

Thus, an emulsion according to the invention has the advantage of being able to be prepared according to a simple “non-microfluidic” process in two stages, namely by simple emulsification, in particular using a Rayneri-type stirring device or a paddle stirrer.

The first step consists in preparing, at a temperature above the melting point of the gelling agents used, an inverse emulsion (E1). An aqueous solution and a fatty solution are prepared separately. It is the addition under stirring of the aqueous phase in the fatty phase which creates the inverse emulsion (E1).

The second step consists in preparing, at a temperature above the melting point of the gelling agents used, in particular in the emulsion (E1), a double emulsion (E2) comprising the emulsion (E1) as dispersed phase. It is the addition under stirring of the emulsion (E1) in the aqueous phase which creates the double water-in-oil-in-water emulsion (E2).

The viscosity of the external aqueous phase can be controlled, in particular, by varying the amount of hydrophilic gelling agent and/or the pH of the solution. In general, the pH of the aqueous phase is less than 4.5, which may involve adding a third sodium hydroxide solution (BF) at the end to reach a pH between 5.5 and 6, 5.

The viscosity of the phases and the shear force applied to the mixtures are the two main parameters which influence the size and the monodispersity of the drops (G1) and (G2) of the emulsions (E1) and (E2).

A person skilled in the art will be able to adjust the parameters of the non-microfluidic process to achieve an emulsion according to the invention and in particular satisfy the drop diameter criteria (G1) and (G2) sought.

An emulsion according to the invention can also be prepared using a microfluidic process, in particular as described in applications WO2012/120043 or WO2019/145424. According to this embodiment, the microfluidic nozzle(s) implemented can have a configuration according to the T geometry, in co-flow (or co-currents), or flow-focusing.

According to this embodiment, the drops (G1), or even the drops (G2), obtained by this microfluidic method advantageously have a uniform size distribution, as described previously.

The presence, in the continuous fatty phase of the drops (G1), of lipophilic gelling agent(s), or even optionally in the internal and/or external aqueous phase, of gelling agent(s) ) hydrophilic(s), may require adjustments in the process for preparing an emulsion according to the invention. In particular, the process for preparing an emulsion according to the invention comprises a step of heating (between 50° C. and 150° C., in particular between 60° C. and 90° C.) at least the fatty phase before mixing/setting in contact with said fatty phase with the internal and external aqueous phases and, where appropriate, maintaining this heating (i) during agitation in the case of a “non-microfluidic” process or (ii) at the level of the device microfluidics in the case of a "microfluidic" process, until the desired emulsion is obtained.

The process for preparing an emulsion according to the invention comprises at least the following steps:
a) have at least:
- an aqueous fluid FE1, optionally at a temperature between 50° C. and 150° C.;
- an oily fluid FI at a temperature of 50° C. to 150° C.; And
- an aqueous fluid FE2, optionally at a temperature between 50°C and 150°C;
b) bringing the aqueous fluid FE1 into contact with the oily fluid FI to form a water-in-oil emulsion consisting of drops (G2), said drops (G2) being formed of the aqueous fluid FE1 dispersed in a continuous fatty phase consisting of the oily fluid FI, and
c) bringing the water-in-oil emulsion obtained in step b) into contact with the aqueous fluid FE2 to form the drops (G1), each drop (G1) comprising at least one, preferably at least two, in in particular at least five, or even at least ten, drop(s) (G2);
in which :
- the aqueous fluid FE1 comprises at least water and optionally at least one hydrophilic gelling agent, at least one active ingredient, and their mixture,
- the oily fluid FI comprises at least one lipophilic gelling agent, and optionally at least one oil and/or at least one active ingredient, the oily fluid FI having a melting point of between 50°C and 100°C, preferably between 60 °C and 90°C, and, at ambient temperature and atmospheric pressure, meets the following physicochemical criteria:
- a hardness (x) of between 2 and 14 N, preferably between 2.5 and 12 N, better still between 3 and 9 N, and very particularly between 4 and 6 N; And
- a tackiness (y) greater than or equal to -2 N, better still greater than or equal to -1 N, and in particular greater than or equal to -0.6 N;
the oily fluid FI further being devoid of amodimethicone; And
- the aqueous fluid FE2 comprises at least water and optionally at least one hydrophilic gelling agent, at least one active ingredient, and a mixture thereof.

Steps (b) and (c) are carried out at a temperature greater than or equal to the melting point of the gelling agent(s) used. In other words, steps (b) and (c) are carried out with an oily fluid FI in a form capable of emulsifying with the aqueous fluid FE1 and the aqueous fluid FE2, or in other words to ensure the formation of the drops (G1) and (G2), and in particular with fluids, and in particular an oily fluid FI, in a liquid form.

According to one embodiment, steps b) and c) above are simultaneous.

According to one embodiment, the fluid FE1 is initially prepared by mixing an aqueous phase intended to form the core of the drops (G2), comprising at least water and additionally, optionally, at least one hydrophilic gelling agent and / or at least one additional compound as mentioned above.

According to one embodiment, the fluid FI is initially prepared by mixing a fatty phase intended to form the core of the drops (G1), comprising at least one lipophilic gelling agent and additionally, optionally, at least one oil and/or at least one additional compound as mentioned above.

According to one embodiment, the fluid FE2 is initially prepared by mixing an aqueous phase intended to form the continuous phase of the emulsion with, optionally, at least one base, at least one additional compound, preservatives and/or other water-soluble products such as glycerin, and most particularly at least one hydrophilic gelling agent.

According to one embodiment, the aqueous continuous phase of the emulsion formed comprises, or even is represented by, the aqueous fluid FE2.

According to another embodiment, the method according to the invention can also comprise a step d) of adding a solution for increasing the viscosity of the external aqueous phase, namely fluid FE2, for example as described in WO2015/055748. Preferably, the viscosity increasing solution is aqueous. This viscosity-increasing solution is typically added to the aqueous fluid FE2 after formation of the drops (G1) and (G2), step d) therefore being subsequent to step c). According to one embodiment, the viscosity-increasing solution comprises a base, in particular an alkali hydroxide, such as sodium hydroxide.

According to one embodiment, in the case of a “microfluidic” process, the process for preparing an emulsion is such that:
- step b) of formation of drops (G2) may comprise the formation of drops of oily fluid FE1 at the outlet of a first conduit opening into the oily fluid FI. Preferably, the oily fluid FI is circulated in a second conduit, the outlet of the first conduit opening into the second conduit, advantageously coaxially with the local axis of the second conduit, and
- step c) of formation of drops (G1) may comprise the formation of drops of oily fluid FI at the outlet of the second conduit opening into the aqueous fluid FE2. Preferably, the aqueous fluid FE2 is circulated in a third conduit, the outlet of the second conduit opening into the third conduit, advantageously coaxially with the local axis of the third conduit.

According to another embodiment, in the case of a “microfluidic” process, the process for preparing an emulsion is such that:
- step (b) of forming the drops (G2) comprises the formation of drops of aqueous fluid FE1 inside a conduit opening into the aqueous fluid FE2; And
- step (c) of formation of drops (G1) comprises the formation of drops of oily fluid FI at the outlet of said conduit opening into the aqueous fluid FE2.

Advantageously, a method of the invention may comprise, after step c) but before step d), a cooling step e) to accelerate the cooling kinetics of the emulsion formed, and thus prevent the risks of coalescence and fragmentation of post-formation drops (between 10 and 30°C).

Preferably, the microfluidic device implemented according to the invention comprises one or more of the following characteristics, taken according to all the technically possible combinations:
- the outlet orifices of the various ducts (or pathways or channels) of the microfluidic device are preferably on the same horizontal axis, so that each drop (G1) and each internal drop(s) (G2) associated droplet(s) are formed simultaneously (in other words, the ends of the IF and MF channels are placed at the same height to generate a single step of drop formation). This embodiment is advantageous in that it allows better control of the number of drop(s) (G2) in each drop (G1);
- at the outlet of the microfluidic device, the different fluids used form a multi-component drop, according to a hydrodynamic mode called “dripping” (drop by drop).

The present invention also relates to an emulsion capable of being obtained by a process such as those described above.

Uses

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

The invention also relates to the use of an emulsion according to the invention for the preparation of a composition, in particular cosmetic, pharmaceutical, in nutrition or in the food industry, preferably of a cosmetic composition and in particular of a composition of caring for and/or making up a keratin material, in particular the skin.

The present invention thus also relates to a composition, in particular cosmetic, and in particular for caring for and/or making up a keratin material, in particular the skin, comprising at least one emulsion according to the invention, optionally in combination with at least a physiologically acceptable environment.

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.

The term "physiologically acceptable medium" is intended to denote a medium which is particularly suitable for applying 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 support on which the composition must be applied, as well as to the appearance in which the composition must be packaged.

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

Thus, the present invention also relates to the non-therapeutic cosmetic use of an aforementioned cosmetic composition, as a product for making up, for hygiene, for cleaning and/or for caring for keratin materials, in particular the skin.

The cosmetic compositions of the invention can be, for example, a cream, a lotion, a serum and a gel for the skin (hands, face, feet, etc.), a foundation (liquid, paste), a preparation for baths and showers (salts, mousses, oils, gels, etc.), a hair care product (hair dyes and bleaches), a cleaning product (lotions, powders, shampoos), a maintenance product for the hair (lotions, creams , oils), a styling product (lotions, lacquers, brilliantines), a shaving product (soaps, foams, lotions, etc.), a product intended to be applied to the lips, a sunscreen product, a tanning product without sun, a product allowing to whiten the skin, an anti-wrinkle product. In particular, the cosmetic compositions of the invention can be an anti-aging serum, a youth serum, a moisturizing serum or a scented water.

Thus, in view of the foregoing, an emulsion or composition according to the invention is oral or topical, preferably topical, and better still topical on a keratin material, in particular the skin, and better still the skin of the face.

The present invention also relates to a non-therapeutic process for the cosmetic treatment of a keratin material, in particular the skin and/or the hair, and more particularly the skin, comprising at least one step of applying to the said keratin material at least one emulsion or a composition according to the invention.

In particular, the present invention relates to a non-therapeutic process for the 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 an emulsion or of a composition according to the invention, for encapsulating at least one hydrophilic compound, in particular a hydrophilic cosmetic active ingredient and, optionally, at least one lipophilic compound, in particular a lipophilic cosmetic active ingredient. .

The present invention also relates to the use of an emulsion or of a composition according to the invention, for improving the surface appearance of the skin, in particular for moisturizing the skin and/or reducing wrinkles and fine lines.

Throughout the description, the expression "comprising a" must be understood as being synonymous with "comprising at least one", unless the contrary is specified. The expressions “included between … and …”, “included from … to …” and “ranging from … to …” must be understood as limits included, unless otherwise specified. The amounts of the ingredients appearing in the examples are expressed in percentage by weight relative to the total weight of the composition, unless otherwise indicated.

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

EXAMPLES

Example 1 : Physicochemical study of fatty phases comprising at least one lipophilic gelling agent

This example consisted in preparing ten anhydrous gels likely to feature the continuous fatty phase of drops G1 of an emulsion according to the invention, and in evaluating their physicochemical properties in terms of hardness (or firmness) (x), stickiness (or adhesion) (y) and cohesion (z). These anhydrous gels differ by the lipophilic gelling agent (ie Rheopearl D2, Estogel M or OILKEMIA™ 5S polymer) and their concentrations (ie 5%, 10% and 15%). In the case of Rheopearl D2, the 1D test differs from the 1C test by the nature of the solvent. Table 1 below shows the composition of these various anhydrous gels.

1A/1B/1C 2A/2B/2C 3A/3B/3C 1D Name INCI %w/w %w/w %w/w %w/w Labrafac CC Caprylic/Capric triglyceride QSP* 0 DUB Inin Isononyl Isononanoate 0 QSP* Meadowfoam Oil Limnanthes alba seed oil 3.00 Rheopearl D2 Dextrin palmitate, Palmitic Acid, Aqua 10/5/15 0 0 15 EMC30 Castor Oil/IPDI Copolymer (and) Caprylic/Capric Triglyceride 0 16.66/33.33/49.99** 0 0 OILKEMIA™ 5S polymer Caprylic/Capric Triglyceride (and) Polyurethane-79 0 0 10/5/15 0 Total 100 * QSP: sufficient quantity for
** EMC30 is a premix of Estogel M (INCI: Castor Oil/IPDI Copolymer (and) Caprylic/Capric Triglyceride) in Caprylic oil/Capric Triglyceride in a 30/70 ratio; the corresponding concentrations of lipophilic gelling agent (ie Estogel M) are therefore respectively 5%/10%/15% relative to the total weight of the anhydrous gel.

The protocol for preparing these anhydrous gels is as follows.
- Mixture A: the solvent (Labrafac CC or DUB Inin) is stirred and heated to 80° C./90° C. depending on the gelling agent to be dispersed; the lipophilic gelling agent (ie Estogel M, Rheopearl D2 or OILKEMIA™ 5S polymer) is added thereto with magnetic stirring at 80° C./90° C. until a homogeneous solution is obtained, guaranteeing good dispersion of the polymer.
- Mixture B: Meadowfoam oil is added to mixture B.

The melting points of the anhydrous gels are measured according to the method described above and are shown in Table 2 below.

Anhydrous gels 1A 1B 1 C 1D 2A 2B 2C 3A 3B 3C Fusion point
(in °C) 48.3 74 82.5 60.1 58.9 68.9 76.6 56 67.8 76

From the 1C and 1D tests, it is observed that the properties of the anhydrous gel, at least in terms of melting point temperature, differ according to the nature of the solvent. The physicochemical criteria x, y and z of the anhydrous gels are then measured using the texturometer protocol described previously.

The corresponding measurements are presented in figures 1 to 7.

There is a graph representing the hardness criterion (x) of the ten anhydrous gels in Table 1.

There is a graph representing the stickiness criterion (y) of the ten anhydrous gels in Table 1. The is an enlargement of the stickiness values (γ) of anhydrous gels 2A, 2B, 2C, 3A, 3B and 3C.

There is a graph representing the cohesion criterion (z) of the anhydrous gels 1B, 1D, 2B and 3B of Table 1.

Finally, Figures 5 to 7 are graphs representing the texturometry curves of the ten anhydrous gels in Table 1. These Figures 5 to 7 give the strength (in N) of the gels in Table 1 as a function of the time (in seconds) during which the gels are subjected (1) to a first compression stage (0 to 5 s) then (2) to a second relaxation stage where the mobile rises (5 to 10 s). After a rest period (10s), the previous steps (1) and (2) are repeated. These Figures 5 to 7 therefore provide information on the physicochemical properties of the gels in Table 1, in particular in terms of hardness, stickiness and cohesion.

Results :

Hardness (x): as can be seen from the , with an identical percentage of lipophilic gelling agent and oily solvent (for example 1B vs. 2B vs. 3B), the differences in terms of hardness profiles of the various anhydrous gels tested are insignificant. Moreover, from the 1C and 1D tests, it is observed that the hardness is impacted by the nature of the solvent.

Sticky (y): as it appears from the , with identical lipophilic gelling agent and oily solvent percentage:
- gels 2 (A, B, C) and 3 (A, B, C) have similar stickiness profiles, and
- gels 1 (A, B, C) exhibit stickiness properties that are markedly superior to those of gels 2 (A, B, C) and 3 (A, B, C).

Moreover, from the 1C and 1D tests, it is observed that the nature of the solvent has a non-negligible impact on the stickiness.

Cohesion (z): as can be seen from the , gels 2B and 3B show similar physicochemical properties in terms of cohesion, clearly inferior to those of gels 1B and 1D.

Example 2 : Preparation of macroscopic double emulsions

In this example 2, ten emulsions are prepared 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 represented by one of the anhydrous gels of the Example 1 and drops (G2) comprising an internal aqueous phase. These emulsions are obtained using a microfluidic manufacturing process as described in WO2015/055748. The microfluidic device implemented is divided into two parts, a first part where is carried out, hot (between 70 and 90°C), the bringing into contact between the internal aqueous phase (also designated IF or FE1) and the fatty phase (also designated MF or FI) and the bringing into contact between the continuous fatty phase FI and the external continuous aqueous phase (also designated OF or FE2) so as to form the water-in-oil-in-water emulsion, and a second part providing rapid cooling of the emulsion formed to accelerate the gelling kinetics of the drops (G1), or even of the drops (G2), and thus prevent the risks of coalescence and fragmentation of the post-formation drops (between 10 and 30°C).

The compositions of the phases (fluids) allowing the preparation of the emulsions are described in Table 3 below.

Phase Trade name Supplier INCI name % w/w Phases IF INTERNAL AQUEOUS GEL PHASE subtotal 100.00 Osmotic water / Aqua qsp* Microcare PE THOR Phenoxyethanol 0.99 PENTIOL GREEN+ / A-LEEN 5 MINASOLVE Pentylenglycol 2.47 Zemea propanediol DUPONT TALE AND LYLE Propanediol 6.94 EDETA BD BASF Disodium EDTA 0.04 Carbopol Ultrez 10 Polymer LUBRIZOL Carbomer 0.26 Unicert red 0.1% solution / / 10.00 10% SODA SOLUTION / AQUA, SODIUM HYDROXIDE 0.11 FM INTERMEDIATE OILY PHASE subtotal 100.00 Anhydrous gel according to example 1 OF EXTERNAL AQUEOUS GEL PHASE subtotal 100.00 Osmotic water / Aqua qsp* Microcare PE THOR Phenoxyethanol 0.99 PENTIOL GREEN+ / A-LEEN 5 MINASOLVE Pentylenglycol 2.47 Zemea propanediol DUPONT TALE AND LYLE Propanediol 6.94 EDETA BD BASF Disodium EDTA 0.04 Carbopol Ultrez 10 Polymer LUBRIZOL Carbomer 0.26 10% SODA SOLUTION / AQUA, SODIUM HYDROXIDE 0.11 * : Sufficient Quantity For.

Below, composition of the soda solution (BF):

BF Trade name Supplier INCI name %w/w Osmotic water qsp 10% SODA SOLUTION / AQUA, SODIUM HYDROXIDE 2.37 Total 100.00

The preparation of each of the above phases falls within the general skills of a person skilled in the art.

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

%/FP IF/FP 4% FI/MF 20% MF/FP 20% (OF+BF)/PF 80%

Experimental apparatus:

The equipment required for the manufacture of emulsions consists of: 4 syringe pumps (one for OF, MF, IF and BF), a syringe heater (for MF), a thermostated bath, a microfluidic device (or nozzle) equipped with concentric pathways.

The nozzle as well as the pipe conveying the oily phase (MF) are placed in a thermostated bath heated between 70°C and 90°C.

The microfluidic device is also adapted to add the sodium hydroxide solution (BF) after formation of the drops (G1) and (G2) in order to enhance the viscosity of the OF.

The flow rates considered for the different phases are presented in the table below.

Phase Flow per nozzle
(in mL/h) IF 4.20 FM 20.5 OF 92.20 BF 6.00

Depending on the configuration of the microfluidic device and the flow rates, the emulsions obtained may comprise G1 drops endowed with satisfactory monodispersity and having an average diameter comprised between 400 μm and 1500 μm, in particular between 700 and 1300 μm. Also, the emulsions obtained may comprise drops G1 comprising between 1 and 20 drops G2, or even between 5 and 10 drops G2, said drops G2 having an average diameter of between 50 μm and 200 μm, in particular between 50 and 100 μm.

Results on the manufacture of emulsions:

It was possible to manufacture emulsions from the ten anhydrous gels according to example 1.

Stability test

• test rouleaux (i.e. mouvement circulaire horizontal) : référence Wheaton, pendant 1 heure ;
• table vibrante (i.e. mouvement circulaire vertical) : référence Heidolph Unimax 1010, pendant 1 heure ; et
• mélangeur 3D (i.e. mouvements aléatoires) : pendant 6 minutes.

Each of the ten emulsions is then packaged in three 30 ml polypropylene (PP) receptacles half-filled. After 1 day at room temperature, each test undergoes one of the three transport tests below (one receptacle per test), namely:

• roller test (ie horizontal circular movement): Wheaton reference, for 1 hour;
• vibrating table (ie vertical circular movement): reference Heidolph Unimax 1010, for 1 hour; And
• 3D mixer (ie random movements): for 6 minutes.

At the end of these stability tests, one evaluates (i) the integrity of the drops G1 and G2, in particular their fragmentation (ii) the turbidity of the gel, generally linked to a transfer of fatty phase in the external continuous aqueous phase and (iii) coloring of the gel, linked to a transfer of colored internal aqueous phase into the external continuous aqueous phase.

Rating criteria :

RATING CRITERIA 0 1 2 3 G1/G2 DROP FRAGMENTATION Lack of fragmentation Slight fragmentation Medium Fragmentation High fragmentation TURBIDITY OF GEL clear gel Slightly cloudy gel Moderately cloudy gel cloudy gel COLORING GEL clear gel Lightly colored gel Medium colored gel colored gel

Results :

Emulsion* D1A D1B D1C D1D D2A D2B D2C D3A D3B D3C BUBBLE FRAGMENTATION 3 1 0 1 3 1 0 2 1 0 TURBIDITY OF GEL 3 1 0 1 3 1 0 2 1 0 COLORING GEL 2 1 0 1 2 1 0 2 1 0 CONCLUSION KO OK KO OK KO OK OK OK OK OK * D1A = water-in-oil-in-water emulsion according to example 2 using as intermediate fatty phase the anhydrous gel 1A of example 1.

The D1A and D2A emulsions show unsatisfactory stability results. The corresponding fatty phases are therefore excluded from the rest of the study. The D3A emulsion presents average stability results but deemed sufficiently satisfactory to be kept for the remainder of the study. The other emulsions tested show satisfactory stability results. These results demonstrate that a fatty phase must have properties in terms of hardness greater than 2 N, preferably greater than or equal to 2.5 N, in particular greater than or equal to 3 N, and better still greater than or equal to 4 N.

Sensory tests

Then, using the eight emulsions above with satisfactory stability, visual and sensory tests were carried out on a cohort of 24 women between 22 and 45 years old. Each woman blindly tested satisfactory emulsions in terms of kinetic stability. The criteria evaluated are (i) the adhesion of the drops of fatty phase to the wall of the packaging, (ii) the aggregation of the drops of fatty phase between them and the ease (or comfort) of application, and in particular the ease crushing and spreading the drops of dispersed phase.

Rating criteria :

RATING CRITERIA 0 1 2 3 MEMBERSHIP
= sticky (y) No Membership Slight adhesion Average Membership Strong adherence AGGREGATION
= cohesion (z) Lack of aggregation Slight aggregation Average aggregation Strong aggregation EASE OF APPLICATION Very satisfying app.
The drops are not (or very little) felt and the mixture between the aqueous phase and the fatty phase takes place easily. Satisfying app.
The drops are very light and the mixture between the aqueous phase and the fatty phase operates easily. Moderately satisfactory application.
The drops are felt and their crushing on the skin generates lumps. The application of the emulsion remains possible. Unsatisfactory application.
The drops are felt and their crushing on the skin generates pieces that are difficult to make disappear by spreading on the skin. The hardness of the drops is too high.

Results :

Emulsion* D1B D1C D1D D2B D2C D3A D3B D3C MEMBERSHIP
= sticky (y) 3 3 3 0 1 0 1 1 AGGREGATION
= cohesion (z) 2 NR** 2 1 NR** NR** 1 NR** EASE OF APPLICATION 1 2 1 1 2 0 1 2 * D1A = emulsion according to example 2 using as fatty phase the anhydrous gel 1A according to example 1.
**NR: Not filled in.

In view of the table above, we observe that a fatty phase:
- in view of the above results in terms of “ease of application” and the , must have a hardness (x) less than or equal to 14 N, better still less than or equal to 12 N, and preferably less than or equal to 9 N,
- in view of the results above in terms of “adhesion” and of figures 2 and 3, that the fatty phase must have a tackiness (y) greater than or equal to -2 N, and better still greater than or equal to -1 N , or even greater than or equal to -0.6 N, and
- in view of the above results in terms of “aggregation” and the , that the fatty phase must have a cohesion (z) less than or equal to 40, preferably less than or equal to 35, and better still less than or equal to 30.

Conclusion

In view of the above results, it is observed that a water-in-oil-in-water emulsion, when the stability of this emulsion is not ensured by the presence of a shell at the "continuous aqueous phase" interface /dispersed fatty phase" or surfactant, may despite everything and unexpectedly present satisfactory properties in terms of kinetic stability and sensoriality, in particular in terms of comfort and ease of application, provided that the fatty phase has:
(i) a melting point of between 50°C and 100°C, preferably between 60°C and 90°C, and,
(ii) at ambient temperature and atmospheric pressure:
- Of a hardness (x) comprised between 2 and 14 N, in particular between 2.5 and 12 N, preferably between 3 and 9 N, and better still between 4 and 6 N;
- of a tackiness (y) greater than or equal to -2 N, better still greater than or equal to -1 N, and in particular greater than or equal to -0.6 N; And
- optionally, of a cohesion (z) less than or equal to 40, preferably less than or equal to 35, and better still less than or equal to 30.

Even more unexpectedly, these results are observed and applicable with an emulsion provided with drops of dispersed fatty phase, or even drops of internal aqueous phase, of macroscopic size.

Example 3 : Preparation of a macroscopic double emulsion with a gelled internal aqueous phase

Example 3 consists in preparing a double emulsion according to the invention which differs from the D2B emulsion of example 2 above by the additional presence in IF of a heat-sensitive hydrophilic gelling agent, the agar-agar present at at 0.10% by weight relative to the total weight of the FI.

It is observed that the presence of this heat-sensitive gelling agent is advantageous in that it makes it possible to further reinforce the kinetic stability of the emulsion according to the invention, and in particular to further reduce the risks of transfer of compounds present in the internal aqueous phase. colored towards the other phases (in particular the external continuous aqueous phase), and this, without negatively impacting the ease (or comfort) of application on the skin.

Claims (21)

Water-in-oil-in-water emulsion, comprising an external continuous aqueous phase, preferably in the form of a gel, and as dispersed phase, a water-in-oil emulsion in the form of drops (G1), each drop ( G1) comprising a continuous fatty phase comprising at least one lipophilic gelling agent and at least one drop (G2) comprising an internal aqueous phase, in which:
- the fatty phase has a melting point of between 50°C and 100°C, preferably between 60°C and 90°C, and, at room temperature and atmospheric pressure, meets the following physicochemical criteria:
- a hardness (x) of between 2 and 14 N, preferably between 2.5 and 12 N, better still between 3 and 9 N, and very particularly between 4 and 6 N; And
- a tackiness (y) greater than or equal to -2 N, better still greater than or equal to -1 N, and in particular greater than or equal to -0.6 N; And
- the emulsion does not include amodimethicone. Emulsion according to Claim 1, characterized in that the fatty phase of the drops (G1) has a cohesion (z) less than or equal to 40, preferably less than or equal to 35, and better still less than or equal to 30. Emulsion according to Claim 1 or Claim 2, characterized in that the drops (G1) and the drops (G2) do not comprise any bark, in particular any bark formed of a layer of coacervate interposed between the continuous fatty phase and the outer continuous aqueous phase or the inner aqueous phase. Emulsion according to any one of Claims 1 to 3, in which the drops (G1) having a diameter greater than or equal to 400 μm represent a volume greater than or equal to 60%, or even greater than or equal to 70%, preferably greater than or equal to 80%, and better still greater than or equal to 90% of the total volume of the continuous fatty phase and/or at least 60%, even at least 70%, preferably at least 80%, and better still at least 90%, of drops (G1) have an average diameter greater than or equal to 400 μm. Emulsion according to any one of Claims 1 to 4, in which the drops (G2) having a diameter greater than or equal to 50 μm represent a volume greater than or equal to 60%, or even greater than or equal to 70%, preferably greater than or equal to 80%, and better still greater than or equal to 90% of the total volume of the internal aqueous phase and/or at least 60%, even at least 70%, preferably at least 80%, and better still at least 90%, of drops (G2) have an average diameter greater than or equal to 50 μm. Emulsion according to any one of Claims 1 to 5, characterized in that the lipophilic gelling agent is chosen from organic or mineral, polymeric or molecular lipophilic gelling agents; fatty substances that are solid at ambient temperature and pressure; and their mixtures. Emulsion according to any one of Claims 1 to 6, comprising from 0.5% to 25%, preferably from 1% to 20%, in particular from 1.5% to 15%, and better still from 2% to 10% , by weight of lipophilic gelling agent(s) relative to the total weight of the continuous fatty phase of the drops (G1). Emulsion according to any one of Claims 1 to 7, in which the continuous fatty phase of the drops (G1) comprises at least one oil chosen from the group consisting of hydrocarbon-based oils of vegetable origin, hydrocarbon-based oils of animal origin, synthetic esters and 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 synthetic esters and ethers, and a mixture thereof, preferably at least one hydrocarbon oil of vegetable origin, and better chosen from meadowfoam seed oil Limnanthes Alba (INCI name: Limnanthes Alba (Meadowfoam) Seed Oil, caprylic and capric acid triglycerides, and mixtures thereof. Emulsion according to any one of Claims 1 to 8, comprising from 0% to 99.5%, preferably from 5% to 95%, in particular from 20% to 90%, better still from 30% to 80%, or even from 50% to 70%, by weight of oil(s) relative to the total weight of the continuous fatty phase of the drops (G1). Emulsion according to any one of Claims 1 to 9, comprising from 0.1% to 70%, preferably from 0.5% to 65%, in particular from 1% to 60%, or even from 3% to 50%, preferably from 5% to 40%, better still from 10% to 30%, and in particular from 15% to 20%, by weight of continuous fatty phase relative to the total weight of the emulsion. Emulsion according to any one of Claims 1 to 10, comprising from 0.1% to 50%, preferably from 1% to 40%, in particular from 2.5% to 30% by weight, and better still from 5% to 20%, by weight of internal aqueous phase relative to the total weight of the continuous fatty phase. Emulsion according to any one of Claims 1 to 11, characterized in that the aqueous continuous phase and/or the internal aqueous phase comprises at least one hydrophilic gelling agent preferably chosen from the group consisting of natural gelling agents; semi-synthetic gelling agents; synthetic gelling agents; and mixtures thereof, and is preferably chosen from Carbomer, alcasealan (INCI: Alcaligenes Polysaccharides), agar-agar, and mixtures thereof. Emulsion according to Claim 12, comprising from 0.0001% to 20%, preferably from 0.001% to 15%, in particular from 0.01% to 10%, and better still from 0.1% to 5%, by weight of hydrophilic gelling agent(s) relative to the total weight of the aqueous phase comprising it(s). Emulsion according to any one of Claims 1 to 13, the said emulsion not comprising any surfactant. Process for preparing an emulsion according to any one of Claims 1 to 14, comprising at least the following steps:
a) have at least:
- an aqueous fluid FE1, optionally at a temperature between 50° C. and 150° C.;
- an oily fluid FI at a temperature of 50° C. to 150° C.; And
- an aqueous fluid FE2, optionally at a temperature between 50°C and 150°C;
b) bringing the aqueous fluid FE1 into contact with the oily fluid FI to form a water-in-oil emulsion consisting of drops (G2), said drops (G2) being formed of the aqueous fluid FE1 dispersed in a continuous fatty phase consisting of the oily fluid FI, and
c) bringing the water-in-oil emulsion obtained in step b) into contact with the aqueous fluid FE2 to form the drops (G1), each drop (G1) comprising at least one drop (G2);
in which :
- the aqueous fluid FE1 comprises at least water and optionally at least one hydrophilic gelling agent, at least one active ingredient, and their mixture,
- the oily fluid FI comprises at least one lipophilic gelling agent, and optionally at least one oil and/or at least one active ingredient, and having a melting point of between 50°C and 100°C, preferably between 60°C and 90°C, and, at ambient temperature and atmospheric pressure, meets the following physicochemical criteria:
- a hardness (x) of between 2 and 14 N, preferably between 2.5 and 12 N, better still between 3 and 9 N, and very particularly between 4 and 6 N; And
- a tackiness (y) greater than or equal to -2 N, better still greater than or equal to -1 N, and in particular greater than or equal to -0.6 N;
the oily fluid FI further being devoid of amodimethicone; And
- the aqueous fluid FE2 comprises at least water and optionally at least one hydrophilic gelling agent, at least one active ingredient, and a mixture thereof. Process according to claim 15, in which steps (b) and (c) are simultaneous. A method according to claim 15, wherein:
- step (b) of forming the drops (G2) comprises the formation of drops of aqueous fluid FE1 inside a conduit opening into the aqueous fluid FE2; And
- step (c) of formation of drops (G1) comprises the formation of drops of oily fluid FI at the outlet of said conduit opening into the aqueous fluid FE2. Emulsion obtainable by a process according to any one of Claims 15 to 17. Composition, in particular cosmetic, in particular for caring for and/or making up a keratin material, comprising at least one emulsion according to any one of Claims 1 to 14 and 18 and optionally at least one physiologically acceptable medium. Non-therapeutic process for the cosmetic treatment of a keratin material, in particular the skin, comprising at least one step of applying to the said keratin material at least one emulsion according to any one of Claims 1 to 14 and 18 or of at least one composition according to claim 19. Use of a water-in-oil-in-water emulsion according to any one of Claims 1 to 14 and 18, for encapsulating at least one hydrophilic compound, in particular a hydrophilic cosmetic active ingredient and, optionally, at least one lipophilic compound, in particular a lipophilic cosmetic active ingredient.