FR3129607A1 - Bi-phasic millimetric emulsion - Google Patents

Abstract

Biphasic millimetric emulsion The present invention relates to a process for forming a biphasic dispersion, said process comprising at least the following steps: (a) disposing, in an intermediate container, of an intermediate dispersion containing an oily phase, in the form of particles (P) and a continuous aqueous phase suspending vis-à-vis the particles (P), (b) conditioning the intermediate dispersion of step (a) in a final container, characterized in that the method comprises, simultaneously in step (b), the addition in continuous aqueous phase of at least one solution comprising at least one raw material capable of reducing the viscosity of the continuous aqueous phase such that it is no longer suspending vis-à-vis particles (P). Figure for abstract: none

Description

Bi-phasic millimetric emulsion

The subject of the present invention is a process for forming a two-phase dispersion, one of the phases of which is in the form of macroscopic drops, including when said dispersion is at rest.

A "biphasic composition" (or "biphase composition") conventionally designates a composition consisting of two distinct liquid phases that are immiscible with each other, which are distinguished from conventional emulsions by the fact that, at rest, the two phases are distinct instead of being emulsified into each other. Thus, the two phases are separated at rest by a single interface, whereas, in conventional emulsions, one of the phases is dispersed in the other in the form of a multitude of droplets, and the interfaces are therefore multiple, and generally stabilized. by emulsifying surfactants and/or emulsifying polymers. A biphasic composition must be of sufficient quality and stability to allow homogeneous application of the two phases, but such that, at rest, the two phases quickly separate and return to their initial state mainly due to phenomena of coalescence of the drops of dispersed phase. between them, this phenomenon being better known under the term "phase shift" (or unmixing).

Multiphase compositions, in particular two-phase or three-phase, are described for example in applications FR 2 638 636, EP 1 064 926, EP 0 370 856 and
EP 0 603 080.

The manufacture of conventional two-phase composition is based on a two-step process, namely:

- Step 1: dispose, in two independent intermediate receptacles, of two liquid phases which are immiscible with each other at ambient temperature and atmospheric pressure, and

- Step 2: inject these two immiscible phases, simultaneously (via double filling) or sequentially, into a final receptacle, generally the primary packaging sold and used/handled by the end user or consumer.

However, this type of process is not suitable for the manufacture of a two-phase composition in the form of a dispersion, at least one of the phases of which is represented by macroscopic drops, and the manufacture of which is based in particular on a microfluidic process, such as by example those described in applications WO 2012/120043,
WO 2017/046305, WO2018077977, FR3063893, PCT/EP2021/063596 and PCT/EP2021/
063598.

Such "microfluidic" processes are particularly sensitive and many parameters are likely to alter their robustness and/or the kinetic stability of the dispersions obtained. In particular, the continuous phase (or second phase) must, at least at the level of the emulsification stage, be sufficiently fluid and homogeneous to allow good emulsification at the level of the injection duct of the dispersed phase (or first phase ) in the second phase. After formation of the drops, the second phase must be suspensive vis-à-vis the drops for:

- preventing/preventing the contact of the drops with each other, and therefore their aggregation, and the adhesion of the drops to the packaging, and therefore guaranteeing satisfactory kinetic stability of the dispersion during its storage in an intermediate container for subsequent packaging in a final container, usually primary packaging; and so

- ensure stable storage to allow, during the packaging of the dispersion, a homogeneous distribution, and therefore an identical number, of (s) drops in each final container.

These two conditions, at first sight contradictory, are generally satisfied by the presence in the second phase of at least one pH-dependent and/or electrolyte-sensitive hydrophilic gelling agent. Preferably, these two conditions are satisfied by the presence in the second phase of at least one pH-dependent hydrophilic gelling agent of the carbomer type, for example those marketed by Lubrizol under the name Carbopol. The gelling/suspensive effect of carbomers is activated by the “neutralization” of the second phase by the addition of a viscosity-increasing solution whose role is to induce a pH increase. Thus, before formation of the dispersion, the second phase has an acid pH, to guarantee a fluidity of the second phase compatible with the microfluidic process. The gelation of the second phase is carried out in a second step, after formation of the dispersion, thanks to a step of injecting the solution for increasing the viscosity of the second phase into the circulation conduit or at the outlet of the conduit. circulation, upstream of the container, as described in application WO2015055748. In other words, the second phase viscosity increasing solution is injected after the first phase drops are formed in the second phase.

Such “microfluidic” processes are therefore particularly effective in forming stable drops of perfectly controlled size, and exhibiting very satisfactory optical properties. Nevertheless, in view of the suspensive nature of the second phase required to ensure the kinetic stability of the dispersion between its manufacture and its packaging in the final container, and as indicated above, methods for manufacturing such dispersions are not suitable for the manufacture of biphasic compositions.

An option aimed at overcoming this drawback would consist, after recovery of the suspension dispersion, in considering a first sieving step to separate the macroscopic drops from the continuous phase, then, during packaging in the final container, a second independent step of mixing said drops in a non-suspensive continuous phase. Such an option is however not desirable because the sieving step is conducive to the aggregation of the drops together and to their deformation and/or breakage. Moreover, this option would require the use of two distinct continuous phases, the first being intended to be discarded. Finally, this option would make it difficult, if not impossible, for a homogeneous distribution, and therefore an identical number, of drops in the final container.

An object of the invention is therefore to provide a simple manufacturing process for a two-phase composition in the form of a dispersion, one of the phases of which is in the form of macroscopic drops which remain stable despite the presence of a continuous nonsuspensive aqueous phase.

To this end, the subject of the invention is a process for forming (or manufacturing) a two-phase dispersion, said process comprising at least the following steps:

(a) disposing, in an intermediate container, of an intermediate dispersion containing an oily phase, in the form of particles (P) and comprising at least one lipophilic gelling agent, dispersed in a continuous aqueous phase comprising at least one hydrophilic gelling agent pH -dependent and/or sensitive to electrolytes and suspensive with respect to particles (P), the oily phase and the aqueous phase being immiscible with each other at ambient temperature and atmospheric pressure,

(b) conditioning the intermediate dispersion of step (a) in a final container,

characterized in that the process comprises, simultaneously with step (b), the addition in the continuous aqueous phase of at least one solution comprising at least one raw material capable of reducing the viscosity of the continuous aqueous phase as it is no longer suspensive vis-à-vis the particles (P).

Within the meaning of the present invention, the dispersion obtained at the end of step (a) and provided with a continuous aqueous phase suspending with respect to the particles (P) can be referred to as “intermediate dispersion” without distinction.

Within the meaning of the present invention, the dispersion obtained at the end of step (b) and provided with a continuous aqueous phase which does not suspend with respect to the particles (P) can be designated either by “final dispersion” or “bi-phasic dispersion”.

Thus, a method according to the invention makes it possible to access biphasic dispersions presenting a novel visual. In particular, when the dispersion according to the invention is at rest, it is in the form of at least two distinct superimposed layers, the oily phase in the form of macroscopic drops (or particles (P)) constituting the upper layer, and the aqueous phase constituting the lower layer. Under agitation, the drops of oily phase mix in the aqueous phase to form a homogeneous product which can then be applied. Then, at rest, the different phases gradually separate and the drops come together to reform the upper layer of oily phase, but while remaining in the form of macroscopic drops, which can easily be redispersed by shaking the product again.

Thus, a biphasic dispersion according to the invention differs from conventional biphasic compositions in that, at rest, the two phases are distinct but the oily phase remains in the form of macroscopic drops. The two phases are therefore always separated by a multitude of interfaces, including at rest; the interface number between the continuous phase and the dispersed phase therefore remains unchanged, whether the dispersion is in a state of rest or after agitation. Thus, in a dispersion according to the invention, the phenomenon of "phase shift" (or demixing) at rest is observed but without coalescence of the drops of oily phase between them. The visual effect obtained with a biphasic dispersion according to the invention is analogous to that of a snow globe.

In addition, the sometimes unsightly appearance of the interfacial zone between the first phase and the second phase encountered with conventional two-phase compositions is not present with a dispersion according to the invention.

In addition, the present invention makes it possible to incorporate into the particles (P) liposoluble active principles which are not very stable in contact with a hydrophilic phase, and this without prejudice to the quality and/or the speed of the phase shift process.

A biphasic dispersion according to the invention also makes it possible to incorporate into the particles (P) active ingredients that are incompatible with other active ingredients, possibly present in the other hydrophilic phase.

A biphasic dispersion according to the invention also makes it possible to incorporate, in the particles (P), active principles which will diffuse into the other hydrophilic phase. It is then possible to adjust the composition of the particles (P) to control the desired diffusion.

There illustrates a biphasic dispersion according to the invention.

In the context of the present invention, an intermediate and/or final dispersion can be designated interchangeably by the term “emulsion”.

By “immiscible” or “immiscible” within the meaning of the present invention, it is meant that the solubility of a first phase in a second phase is advantageously less than 5% by mass.

The particles (P) of a dispersion according to the invention are advantageously substantially spherical and advantageously exhibit an apparent monodispersity (i.e. they are perceived by the eye as spheres identical in diameter). In the rest of the present description, the particles (P) can be designated interchangeably by the terms “drops”, “macroscopic drops” or “drops (G1)”.

According to one embodiment, a biphasic dispersion according to the invention is all the more advantageous in that it does not comprise any surfactant.

Unless otherwise indicated, in all that 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 1013 mbar ).

The invention also relates to a composition, in particular a cosmetic composition, comprising a biphasic dispersion according to the invention, preferably in combination with a physiologically acceptable medium.

The 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 a step of applying to the said keratin material a biphasic dispersion or a cosmetic composition according to the invention.

Dispersion

A dispersion according to the invention comprises an oily phase in the form of macroscopic drops dispersed in a continuous aqueous phase, the dispersed phase and the continuous phase being mutually immiscible at room temperature and atmospheric pressure.

A dispersion according to the invention has the advantage of being stable (or
“kinetically stable”), in particular over time and during transport. By
"stable" is particularly intended to denote, within the meaning of the present invention, the absence of opacification of the continuous aqueous phase, the absence of aggregation of the drops between them, and in particular the absence of coalescence or ripening of 'Oswald of the drops between them, the absence of leakage of materials from the dispersed phase to the continuous phase, or vice versa, and the absence of adhesion of the drops to the internal walls of the containers.

For obvious reasons, the stability within the meaning of the present invention does not take into account the parameter “absence of creaming or sedimentation of the drops of dispersed phase in the continuous phase”.

Continuous aqueous phase

As indicated previously, a dispersion according to the invention comprises a continuous aqueous phase which is liquid at ambient temperature and atmospheric pressure, and whose suspensive nature with respect to the particles (P) evolves during the manufacturing process.

Thus, within the meaning of the present invention:

- By “suspensive”, is meant the capacity of the continuous aqueous phase to suspend the particles (P) over a period of time greater than 1 month, preferably greater than 3 months, and better still greater than 6 months; And

- by "non-suspensive", "not suspensive" or "more suspensive", is meant the ability of the continuous aqueous phase to allow the separation (or creaming) between said particles (P) and the continuous aqueous phase over a period of time of less than 1 day, in particular less than 1 hour, better still less than 30 minutes, and preferably less than 5 minutes.

In other words, the continuous aqueous phase is not solid at room temperature and at room pressure.

According to one embodiment, the continuous aqueous phase is translucent, even transparent, and preferably transparent.

The property of transparency or translucency is determined as follows: the phase to be tested is poured into a 30 ml Volga jar, the phase is left for 24 hours at room temperature and a white sheet is placed underneath on which is drawn with a marker black a cross about 2 mm thick. If the cross is visible to the naked eye in daylight at a viewing distance of 40 cm, the phase is transparent or translucent.

This transparent or translucent aspect is favored to guarantee the differentiating visual conferred by the particles (P), or even (P'), and therefore the presence of a significant aesthetic element.

An aqueous phase according to the invention comprises water and at least one pH-dependent and/or electrolyte-sensitive hydrophilic gelling agent.

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 continuous 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 the continuous aqueous phase.

pH-dependent hydrophilic gelling agent and/or electrolyte sensitive

The continuous aqueous phase comprises at least one pH-dependent and/or electrolyte-sensitive hydrophilic gelling agent.

As indicated above, the gelling/suspensive effect of a pH-dependent hydrophilic gelling agent is activated by the “neutralization” of the second phase by the addition of a viscosity-increasing solution whose role is to induce an increase in pH.

The gelling/suspensive effect of an electrolyte-sensitive hydrophilic gelling agent is activated by the addition of electrolytes in the second phase, for example by adding a solution comprising sodium or potassium ions.

Preferably, a pH-dependent and/or electrolyte-sensitive hydrophilic gelling agent is chosen from copolymers of acrylic acid or maleic acid and other monomers, such as acrylamide, alkyl acrylates, acrylates C5-C8 alkyl, C10-C30 alkyl acrylates, C12-C22 alkyl methacrylates, methoxypolyethylene glycol methacrylates, hydroxyester acrylates, crosspolymer acrylates, and mixtures thereof.

Preferably, a pH-dependent and/or electrolyte-sensitive hydrophilic gelling agent is an optionally cross-linked poly(acrylic acid) (or "carbomer").

In the context of the invention, and unless otherwise stated, the term “carbomer” is understood to mean an optionally crosslinked homopolymer, resulting from the polymerization of acrylic acid. It is therefore an optionally crosslinked poly(acrylic acid). Among the carbomers of the invention, mention may be made of those marketed under the names ^Tego® Carbomer 340FD from Evonik, ^Carbopol® 981 from Lubrizol, Carbopol ETD 2050 from Lubrizol, or else Carbopol Ultrez 10 from Lubrizol.

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

Preferably, an intermediate and/or final dispersion according to the invention can comprise from 0.01% to 5% by weight, preferably from 0.05% to 2%, and preferentially from 0.10% to 0.5% , hydrophilic gelling agent(s) pH-dependent and/or sensitive to electrolytes, in particular carbomer(s), relative to the weight of the continuous aqueous phase of the dispersion intermediate and/or final according to the invention.

Of course, those skilled in the art will take care to adjust the nature and/or the contents of hydrophilic gelling agent(s) pH-dependent and/or sensitive to electrolytes so as to guarantee the proper functioning of the manufacturing process, in particular to ensure the suspensive nature vis-à-vis the particles (P) of the intermediate dispersion. These adjustments are within the general knowledge of those skilled in the art.

Dispersed oily phase

An oily phase (or fatty phase) according to the invention comprises at least one oil and at least one lipophilic gelling agent.

Oils

The oily phase can comprise at least one oil, preferably in which the cationic polymer as described below (when present) is soluble.

The term “oil” is understood to mean a fatty substance that is liquid at room temperature.

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

- hydrocarbon oils of plant origin, such as hydrogenated jojoba oil, hydrogenated sunflower oil, hydrogenated castor oil, hydrogenated coconut oil;

- 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 R1COOR2 and R1OR2 in which R1 represents the residue of a C8 to C29 fatty acid, and R2 represents a hydrocarbon chain, branched or not, C3 to C30, such as Purcellin oil, isononyl isononanoate, isodecyl neopentanoate, isopropyl myristate, ethyl-2-hexyl palmitate, octyl-2 stearate -dodecyl, octyl-2-dodecyl erucate, isostearyl isostearate; hydroxylated esters such as isostearyl lactate, octylhydroxystearate, octyldodecyl hydroxystearate, diisostearyl-malate, triisocetyl citrate, fatty alcohol heptanoates, octanoates, decanoates; 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 Parléam 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 with 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.

According to a preferred embodiment, the oil is selected from the group consisting of isononyl isononanoate, dimethicone, isohexadecane, polydimethylsiloxane, octyldodecanol, isodecyl neopentanoate and mixtures thereof .

Advantageously, a dispersion according to the invention comprises at least one non-volatile hydrocarbon oil containing more than 90%, preferably more than 95%, of fatty acids with a chain length greater than or equal to 18 carbon atoms, preferably greater than or equal to equal to 20 carbon atoms, in particular comprised between C18 and C36, preferably between C20 and C28, and better still between C20 and C22 (H1 oil).

By "non-volatile", we mean an oil whose vapor pressure at room temperature and atmospheric pressure is non-zero and less than 0.02 mm Hg (2.66 Pa) and better still less than 10-3 mm Hg (0.13Pa).

Thus, as H1 oils, mention may be made of jojoba oil, linseed oil, Perilla oil, Inca Inchi oil, rosehip oil, rapeseed oil, hemp oil, sweet almond oil, corn oil, apricot oil, castor oil, Meadowfoam oil (INCI: Limnanthes Alba (Meadowfoam) Seed Oil) and mixtures thereof, preferably jojoba oil and/or Meadowfoam oil, and more preferably Meadowfoam oil.

According to another preferred embodiment, the fatty phase does not include silicone oil, and preferably does not include polydimethylsiloxane (PDMS).

The oily phase advantageously comprises meadowfoam oil (eg 20% by weight relative to the weight of the oily phase). Indeed, the presence of this oil, when coupled with Estogel M (via EMC30), increases the mechanical strength of the particles (P) which is particularly useful in the case of a two-phase composition where the particles (P ) undergo much greater stresses than in a conventional composition, ie where the viscosity of the continuous aqueous phase is adjusted to suspend said particles (P) in a stable manner.

A person skilled in the art will know how to adjust the nature and/or the content of the oil(s), in particular to ensure satisfactory kinetic stability of the dispersion according to the invention and to retain the aforementioned advantageous technical effects.

According to one embodiment, a dispersion according to the invention comprises between 0.1% and 99.99%, in particular between 1% and 99%, preferably between 20% and 90%, and in particular between 30% and 60 %, by weight of oil(s) relative to the total weight of the oily phase comprising it/them.

Lipophilic gelling agent

A lipophilic gelling agent can be chosen from organic or inorganic, polymeric or molecular gelling agents; fatty substances that are solid at ambient temperature and pressure, chosen in particular from waxes, pasty fatty substances, butters; and their mixtures.

Such lipophilic gelling agents are in particular described in WO2019002308.

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.

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 (INCI name: dextrin palmitate), Rheopearl® TT2 (INCI name: dextrin palmitate ethylhexanoate), and Rheopearl® MKL2 (INCI name : dextrin myristate) by the company Miyoshi Europe, also the dextrin palmitate marketed by The Innovation Company.

Among the polymeric gelling agents, mention may be made of THIXCIN® R from Elementis Specialties (INCI: Trihydroxystearin), OILKEMIA™ 5S polymer from Lubrizol (INCI: Caprylic/Capric Triglyceride (and) Polyurethane-79) or Estogel M from PolymerExpert (INCI: CASTOR OIL / IPDI COPOLYMER & CAPRYLIC / CAPRIC TRIGLYCERIDE).

Among waxes and 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, shea butter, Shea Nilotica 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 ), butter ( Prunus Armeniaca ), Macadamia butter ( Macadamia Temifolia ), grapeseed butter ( Vitis vinifera ), avocado butter ( Persea gratissima ), olive butter ( Olea europaea ), butter 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 the INCI name Irvingia Gabonensis Kernel Butter, jojoba esters (mixture of wax and hydrogenated jojoba oil) (INCI name: Jojoba esters) and ethyl esters of shea butter (INCI name: Shea butter ethyl esters), and their mixtures.

According to a particular embodiment, the oily phase 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 lipophilic gelling agent is chosen from dextrin palmitates, Estogel M from PolymerExpert (INCI: CASTOR OIL / IPDI COPOLYMER & CAPRYLIC / CAPRIC TRIGLYCERIDE), OILKEMIA™ 5S polymer from Lubrizol (INCI: Caprylic/Capric Triglyceride (and) Polyurethane-79), and mixtures thereof.

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 ambient temperature and liquid at a temperature above 40° C., preferably above 50° C.

Advantageously, a lipophilic gelling agent is a thixotropic gelling agent or one capable of conferring on the phase which comprises it a thixotropic behavior. Such a thixotropic gelling agent is chosen in particular from the fumed silicas optionally treated hydrophobic, described above.

According to the invention, an intermediate and/or final dispersion according to the invention can comprise from 0.01% to 99.90%, in particular from 0.05% to 90%, preferably from 0.1% to 70% , in particular from 0.25% to 50%, better still from 0.5% to 40%, in particular from 1% to 30%, and preferentially from 2.5% to 20%, by weight of agent(s) lipophilic gelling agent(s) relative to the total weight of the dispersed oily phase.

In view of the above, the dispersed oily phase preferably has a lower density than the continuous aqueous phase.

Of course, those skilled in the art will take care to adjust the parameters of the manufacturing process to guarantee its proper functioning, in particular so as to ensure the implementation of phases endowed with an appropriate fluidity which can be achieved in particular by raising the temperature of said phases. These adjustments are within the general knowledge of those skilled in the art.

Particles (P)

As described previously, the dispersed oily phase is in the form of macroscopic drops, i.e. visible to the naked eye. Thus, in an intermediate and/or final dispersion according to the invention, the phases constituting it form therein a macroscopically inhomogeneous mixture, including when the dispersion is at rest.

By “macroscopic” within the meaning of the present invention, is meant particles (P) having a diameter (or size) greater than or equal to 100 μm.

According to a preferred embodiment:

- drops having a diameter greater than or equal to 100 μm, preferably greater than or equal to 150 μm, better still greater than or equal to 200 μm, in particular greater than or equal to 250 μm, preferably greater than or equal to 300 μm, in particular greater than or equal to 400 μm and better still greater than or equal to 500 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% the total volume of the dispersed phase; and or

- at least 60%, or even at least 70%, preferably at least 80%, and better still at least 90%, of the drops have a diameter greater than or equal to 100 μm, preferably greater than or equal to 150 μm, better still greater than or equal to 200 μm, in particular greater than or equal to 250 μm, preferably greater than or equal to 300 μm, in particular greater than or equal to 400 μm and better still greater than or equal to 500 μm.

According to a first variant, the particles (P) are translucent, even transparent.

According to another preferred variant, the particles (P) are colored.

Particles (P) are not metal, glass or ceramic.

The particles (P) can be monophasic or multiphasic.

The particles (P) can be represented by:

- spheres (or solid or matrix particles);

- capsules (or particles of the “core/shell” or “core/shell” type), preferably comprising a liquid core or at least partly gelled or at least partly thixotropic; And

- their mixture.

According to one embodiment, a particle (P) according to the invention is a solid (or monophasic) particle. According to another embodiment, a particle (P) according to the invention is a capsule.

A sphere or the core of a capsule according to the invention can be monophasic and/or comprise an intermediate drop of an intermediate phase, said intermediate drop comprising at least one internal drop of an internal phase.

The intermediate phase is for example made from a solution that is immiscible with the internal phase at ambient temperature and atmospheric pressure. By way of illustration, when the intermediate phase is oily, the internal phase is aqueous.

Thus, a dispersion according to the invention may be:

- a simple dispersion of the direct type (i.e. of the oil-in-water type); Or

- a multiple dispersion, in particular double, and in particular of the water-in-oil-in-water or oil-in-oil-in-water type.

Advantageously, the intermediate phase comprises at least one lipophilic gelling agent, in particular as defined above, to improve the suspension of the internal drop(s) placed in the intermediate drop according to this method of production and thus prevent/avoid the phenomena of creaming or sedimentation of the internal drop(s) placed in the intermediate drop.

According to one embodiment, the capsules comprise a gelled envelope or a shell totally encapsulating said core, preferably a shell comprising at least one gelled polyelectroyte, at least one polymer, or deriving from a complex coacervation reaction between at least one anionic polymer, preferably hydrophilic, and at least one cationic polymer, preferably lipophilic.

In addition, the particles (P) advantageously exhibit an apparent monodispersity (i.e. they are perceived by the eye as spheres identical in diameter). The drops are advantageously substantially spherical.

Preferably, the dispersions of the invention consist of a population of monodispersed drops, in particular such that they have a coefficient of variation Cv of less than 10%, or even less than 3%, in particular for an average diameter comprised from 100 μm to 3000 μm, in particular from 500 μm to 2000 μm.

In the context of the present description, the term "monodispersed drops" means the fact that the population of drops of the dispersion 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 dispersion.

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. N is advantageously greater than or equal to 100, in particular in the case where the dispersion is polydispersed.

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 dispersion:

The standard deviation σ of a dispersion reflects the distribution of the diameters D _i of the drops of the dispersion around the average diameter .

Knowing the mean diameter and the standard deviation σ of a dispersion, 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 dispersion according to this mode 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 according to this mode of the invention is less than 10%, preferably less than 5%, or even less than 3%.

Alternatively, the monodispersity can be demonstrated by placing a dispersion sample in a bottle with a constant circular section. Gentle agitation by rotation of a quarter turn over half a second around the axis of symmetry crossing the bottle, followed by a rest of half a second is carried out, before repeating the operation in the opposite direction, and this four times in a row.

The drops of the dispersed phase organize themselves in a crystalline form when they are monodispersed. Thus, they have a stack according to a following repeating pattern in three dimensions. It is then possible to observe, a regular stacking which indicates a good monodispersity, an irregular stacking translating the polydispersity of the dispersion.

To obtain monodisperse drops, the microfluidic technique can also be implemented (Utada et al. MRS Bulletin 32, 702-708 (2007); Cramer et al. Chem. Eng. Sci. 59, 15, 3045-3058 (2004)), and more particularly microfluidic devices of the co-flow type (the fluids go in the same direction) or flow-focusing (the fluids go in different directions, and typically in opposite directions).

According to a particular embodiment, a dispersion according to the invention further comprises a third phase, aqueous and/or oily, in the form of particles (P'), different from the particles (P), dispersed in the continuous aqueous phase, and preferably comprising a lower density (but different from the density of the particles (P)), identical to or higher than that of the continuous aqueous phase. This embodiment allows the presence, in the same dispersion, of lipophilic raw materials, in particular active ingredients, incompatible with each other or capable of reacting at the time of application to the surface to be treated. This embodiment also allows novel visuals.

According to a first variant where the particles (P') have a density identical to that of the continuous aqueous phase, when the dispersion according to the invention is at rest, it is in the form of at least two distinct superimposed layers, the oily phase in the form of particles (P) constituting the upper layer, and the aqueous phase constituting the lower layer further comprising suspended particles (P').

According to a second variant where the particles (P') have a higher density than that of the continuous aqueous phase, when the dispersion according to the invention is at rest, it is in the form of at least three distinct superimposed layers, the oily phase in the form of particles (P) constituting the upper layer, the aqueous phase constituting the intermediate layer and the phase in the form of particles (P') constituting the lower layer.

The particles (P′) can in particular be chosen from spheres, capsules, reflective particles, in particular flakes, in particular as defined in FR3082731, and mixtures thereof.

Preferably, a dispersion according to the invention, in particular a final dispersion, comprises between 1% and 40%, preferably between 2% and 25%, preferentially between 3% and 15%, and in particular between 4% and 10% , by weight of particles (P) relative to the total weight of the intermediate and/or final dispersion.

According to a particular embodiment:

- the continuous aqueous phase can be in the form of a direct emulsion, the size of the drops (G2) preferably being smaller than the size of the drops (G1); and or

- the dispersed oily phase, or even the intermediate phase and/or the internal phase in the case of a multiple dispersion (or complex capsule) as defined below, can be in the form of an emulsion respectively in the form of drops (G3) and/or (G4), the size of the drops (G3) and/or (G4) necessarily being smaller than the size of the drops (G1).

The drops (G2) and/or (G3) and/or (G4) are preferably microscopic, that is to say not visible to the naked eye and in particular of a size less than 100 μm, preferably less to 20 μm, and better still less than 10 μm. Preferably, the size of the drops (G2) and/or (G3) and/or (G4) is between 0.1 μm and 90 μm, preferably between 0.25 μm and 75 μm, in particular between 0.5 μm and 50 μm, and preferably between 1 μm and 20 μm.

Optionally, the drops (G2) and/or (G3) and/or (G4) comprise a shell formed from at least one anionic polymer, in particular a carbomer, and from at least one cationic polymer, in particular an amodimethicone, as defined below.

In other words, the drops (G2) and/or (G3) and/or (G4) are different and independent of the drops (G1).

These drops (G2) and/or (G3) and/or (G4), of reduced size, allow the implementation of ingredients that are incompatible or poorly compatible with each other when present within the same phase and/or allow have an effect on the texture. Indeed, a dispersion according to the invention comprising such finely dispersed drops (G2) and/or (G3) and/or (G4) has improved smoothness qualities.

bark of drops

According to a first embodiment, the drops of a dispersion according to the invention are devoid of shell, in particular of polymeric membrane or membrane formed by interfacial polymerization. In particular, the drops of a dispersion according to the invention are not stabilized using a coacervate membrane (anionic polymer type (carbomer)/cationic polymer (amodimethicone)). In other words, the contact between the continuous phase and the dispersed phase is direct.

According to another embodiment, the drops of the dispersed phase also comprise a shell. This bark can be as defined in WO2015166454.

According to a first variant, the shell completely encapsulating the core is typically based on at least one gelled polyelectrolyte and/or at least one polymer, preferably heat-sensitive, for example agar-agar.

According to another preferred variant, the drops according to the invention are surrounded by a shell comprising at least one anionic polymer and at least one cationic polymer, in particular a shell deriving from a complex coacervation reaction between at least one polymer anionic, preferably hydrophilic, and at least one cationic, preferably lipophilic polymer.

According to the invention, the drops obtained may have a very thin shell, in particular with a thickness of less than 1% of the diameter of the drops.

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

According to one embodiment, the thickness of the shell of the drops is less than 1000 nm, in particular comprised from 1 to 500 nm, preferably less than 100 nm, advantageously less than 50 nm, preferentially less than 10 nm.

The measurement of the thickness of the shell of the drops of the invention can be carried out by the small-angle neutron scattering method (Small-Angle X-ray Scattering), as implemented in Sato et al. J. Chem. Phys. 111, 1393-1401 (2007).

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

After washing, the drops are then transferred into the Neutron cell in order to determine the I(q) spectrum; q being the wave vector.

From this spectrum, classical analytical treatments (REF) are applied in order to determine the thickness of the hydrogenated (non-deuterated) bark.

According to one embodiment, the shell surrounding the drops of the dispersed phase is stiffened, which in particular confers good resistance to the drops and reduces, or even prevents, their coalescence.

This shell is typically formed by coacervation, i.e. by precipitation of polymers charged with opposite charges. Within a coacervate, the bonds linking the charged polymers together are of the ionic type, and are generally stronger than the bonds present within a membrane of the surfactant type.

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

The formation of the coacervate between these two polymers can be caused by a modification of the conditions of the reaction medium (temperature, pH, concentration of reagents, etc.).

The coacervation reaction results from the neutralization of these two polymers charged with opposite polarities and allows the formation of a membrane structure by electrostatic interactions between the anionic polymer and the cationic polymer. The membrane thus formed around each drop typically forms a shell which completely encapsulates the core of the drop, and thus isolates the core of the drop from the continuous aqueous phase.

The anionic and cationic polymers are in particular different from the oils described previously described above. On the other hand, the anionic polymer can be identical to the pH-dependent and/or electrolyte-sensitive hydrophilic gelling agent described above, in particular when the latter is a carbomer.

Anionic polymer

In the context of the present description, the term “polymer of the anionic type” or “anionic polymer” is understood to mean a polymer comprising chemical functions of the anionic type. We can also speak of anionic polyelectrolyte.

By “chemical function of the anionic type”, is meant a chemical function AH capable of donating a proton to give a function A ⁻ . Depending on the conditions of the medium in which it is found, the polymer of the anionic type therefore comprises chemical functions in the AH form, or else in the form of its conjugate base A ⁻ .

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

As an example of an anionic-type polymer, mention may be made of any polymer formed by the polymerization of monomers at least part of which bears chemical functions of the anionic type, such as carboxylic acid functions. Such monomers are for example acrylic acid, maleic acid, or any ethylenically unsaturated monomer comprising at least one carboxylic acid function. It may for example be an anionic polymer comprising monomer units comprising at least one chemical function of the carboxylic acid type.

Preferably, the anionic polymer is hydrophilic, that is to say soluble or dispersible in water.

Among the examples of anionic-type polymer suitable for implementing the invention, mention may be made of copolymers of acrylic acid or maleic acid and other monomers, such as acrylamide, alkyl acrylates , C ₅ -C ₈ alkyl acrylates, C ₁₀ -C ₃₀ alkyl acrylates, C ₁₂ -C ₂₂ alkyl methacrylates, methoxypolyethylene glycol methacrylates, hydroxyester acrylates, crosspolymer acrylates , and mixtures thereof.

According to the invention, a polymer of the anionic type is preferably a carbomer as described previously. This polymer can also be an acrylates/C _10-30 alkyl acrylate crosslinked copolymer _{(INCI name: acrylates/C 10-30 alkyl acrylate} Crosspolymer).

According to one embodiment, the shell of the drops comprises at least one anionic polymer, such as for example a carbomer as described previously.

A dispersion according to the invention may comprise from 0.01% to 5% by weight, preferably from 0.05% to 2%, and preferably from 0.10% to 0.5%, of anionic polymer(s) ( s), in particular of carbomer(s), relative to the weight of the phase comprising it(s), or even relative to the total weight of the dispersion.

According to the invention, the dispersions according to the _{invention may comprise a carbomer and a crosslinked acrylate/C 10-30 alkyl} acrylate copolymer, in particular as described in WO2017046305.

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

According to the invention, the dispersions according to the invention can comprise a carbomer and a crosslinked copolymer ^Carbopol® Aqua SF1 (INCI name=Acrylates copolymer).

Cationic polymer

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

Preferably, the cationic polymer is lipophilic or liposoluble.

In the context of the present application, and unless otherwise stated, by “chemical function of the cationic type”, is meant a chemical function B capable of capturing a proton to give a BH ⁺ function. Depending on the conditions of the medium in which it is found, the cationic-type polymer therefore comprises chemical functions in the B form, or else in the BH ⁺ form, its conjugate acid.

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

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

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

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

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

Mention may be made of the bis-isobutyl PEG-14/amodimethicone copolymer, the Bis(C13-15 Alkoxy) PG-Amodimethicone, the Bis-Cetearyl Amodimethicone and the bis-hydroxy/methoxy amodimethicone.

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

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

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

According to one embodiment, the cationic polymer is a silicone polymer modified with a primary, secondary or tertiary amine function, such as amodimethicone.

According to one embodiment, the drops, and in particular the bark of said drops, comprise amodimethicone.

According to a particularly preferred embodiment, the cationic polymer corresponds to the following formula:

in which :

- R ₁ , R ₂ and R ₃ , independently of each other, represent OH or CH ₃ ;

- R ₄ represents a group -CH ₂ - 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, preferably between 2 and 100, and better still between 2 and 20; And

- z is an integer between 0 and 10, preferably between 0 and 1, and better still is equal to 1.

In the aforementioned formula, when R ₄ represents an -X-NH- group, X is connected to the silicon atom.

In the aforementioned formula, R ₁ , R ₂ and R ₃ preferably represent CH ₃ .

In the above formula, R ₄ is preferably a -(CH ₂ ) ₃ -NH- group.

According to the invention, the dispersion may comprise from 0.01% to 10%, preferably from 0.05% to 5%, by weight of cationic polymer(s), in particular amodimethicone(s), by relative to the weight of the phase comprising it(s).

Viscosity increasing solution

Step (a) of a manufacturing process according to the invention assumes that the viscosity of the continuous aqueous phase is increased to maintain the particles (P) in suspension, preferably over a period of time of at least 1 month , preferably at least 3 months, better still at least 6 months, and most particularly at least 12 months.

The increase in viscosity, or even the gelling of the continuous aqueous phase, is obtained by injecting at least one viscosity-increasing solution, according to the process according to the invention which will be described in more detail below.

Preferably, the solution for increasing the viscosity is for example a solution containing a base.

It may comprise a single base or a mixture of several different bases. According to this particular embodiment, the presence of at least one base in said aqueous continuous 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 one embodiment, the base present in the 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 intermediate, or even biphasic, dispersion 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 mineral base, and in particular NaOH, relative to the total weight of continuous aqueous phase.

Preferably, during the formation of the particles (P), the viscosity of the second phase, namely that dedicated to forming the continuous aqueous phase of the intermediate dispersion, is advantageously less than 20,000 mPa.s, in particular less than 10,000 mPa. .s, preferably less than 5000 mPa.s, and more preferably is between 300 mPa.s and 3000 mPa.s.

Once the particles (P) have formed, the viscosity of the second phase of the intermediate dispersion is increased to be greater than or equal to 3000 mPa.s, preferably greater than or equal to 5000 mPa.s, better still is between 3000 mPa. s and 10000 mPa.s, and in particular is between 4000 mPa.s and 6000 mPa.s.

The viscosity is measured at ambient temperature and at ambient pressure, by the method described in WO2017046305.

Solution comprising at least one raw material capable of reducing the viscosity of the phase aqueous keep on going

As indicated above, step (b) of a manufacturing process according to the invention assumes that the viscosity of the continuous aqueous phase of the intermediate dispersion is reduced to allow separation (or creaming) between said particles (P) and the aqueous phase continues over a period of time of less than 1 day, in particular less than 1 hour, better still less than 30 minutes, and preferably less than 5 minutes.

This reduction in the viscosity of the continuous aqueous phase of the intermediate dispersion is obtained by injecting at least one solution comprising at least one raw material capable of reducing the viscosity of the continuous aqueous phase of the intermediate dispersion, according to the method according to invention which will be described in more detail below.

The solution comprising at least one raw material capable of reducing the viscosity of the continuous aqueous phase may also be referred to as “viscosity reduction solution” without distinction.

Preferably, a raw material capable of reducing the viscosity of the continuous aqueous phase may be chosen from water, at least one salt, at least one acid, at least one chelating agent, and mixtures thereof.

Preferably:

- the salt is chosen from mineral salts, preferably a chloride salt, and in particular chosen from calcium chloride, sodium chloride;

- the acid is chosen from an aminopolycarboxylic acid, citric acid, salicylic acid, glycolic acid, lactic acid, malic acid, tartaric acid, acetic acid, acetylsalicylic acid , ascorbic acid, hydrochloric acid, sulfuric acid, nitric acid, formic acid, preferably citric acid;

- the chelating agent comprising at least one cation is chosen from ethylenediaminedisuccinic acid (or EDDS), ethylenediaminetetraacetic acid (or EDTA), Trisodium Ethylenediamine Disuccinate such as for example the product Natrlquest E30 marketed by Innospec; And

- their mixtures.

It should be noted that the aqueous phase of an intermediate dispersion can advantageously comprise at least one chelating agent, the latter being in fact useful for maintaining the stability of the intermediate dispersion. A process according to the invention is therefore also advantageous in that the addition of the solution for reducing the viscosity, in particular in the presence of at least one chelating agent, makes it possible to reduce the content of gelling agent(s). ) hydrophilic (s) pH-dependent and / or sensitive (s) to electrolytes, in particular carbomer (s). Nevertheless, an intermediate dispersion according to the invention must preferably be completely neutralized before adding the solution for reducing the viscosity. Thus, the pH of an intermediate dispersion according to the invention is advantageously between 5 and 7.5, preferably between 5.2 and 7. Indeed, at acid pH, in particular at pH less than 5, the addition in intermediate dispersion of a solution for reducing the viscosity, in particular in the presence of at least one chelating agent, could on the contrary induce an increase in the viscosity of the continuous aqueous phase, which is not desirable. Those skilled in the art will know how to adjust the pH of the continuous aqueous phase of the intermediate dispersion to prevent this type of unwanted phenomenon.

Preferably, the continuous aqueous phase of a final dispersion may comprise between 0.01% and 1%, preferably between 0.02% and 0.75%, and better still between 0.03% and 0.5%, in weight of raw material(s) capable of reducing the viscosity of the continuous aqueous phase of the intermediate dispersion relative to the total weight of the continuous aqueous phase of the final dispersion.

Preferably, a final dispersion according to the invention may comprise between 1% and 10%, preferably between 2% and 7.5%, and better still between 4% and 6%, by weight of viscosity reduction solution with respect to to the total weight of the continuous aqueous phase of the final dispersion.

Preferably, the mass ratio between the continuous aqueous phase of the intermediate dispersion and the solution for reducing the viscosity is between 80/20 and 99/1, and better still between 90/10 and 95/5.

Preferably, the continuous aqueous phase of the final dispersion has a yield value of less than 2 Pa, preferably less than 1 Pa.

This flow threshold value can be obtained by any method known to those skilled in the art, for example by amplitude scanning with a rheometer. By way of illustration, reference may be made to the scientific publication Dubash et al., J. Non-Newtonian Fluid Mech. 142 (2007) 123–134.

Additional compound(s)

According to the invention, a dispersion according to the invention, in particular the continuous phase and/or the dispersed phase, can also comprise at least one additional compound other than oils, gelling agents, and raw materials suitable reducing the viscosity of the aforementioned continuous aqueous phase.

The dispersions according to the invention can thus additionally comprise powders; reflective particles, in particular sequins, in particular as defined in FR3082731; 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; fillers, in particular as described in FR1755907; emulsifying and/or non-emulsifying silicone elastomers, in particular as described in EP2353577; “soft focus” fillers; texture agents, in particular polyethylene glycols (e.g. marketed under the name Carbowax) or glycerin; curators; humectants; stabilizers; chelators; emollients; additional hydrophilic gelling agents, in particular as described below; pH modifiers, osmotic force modifiers and/or refractive index modifiers etc. or any usual cosmetic additive; and their mixtures.

Also, the dispersions according to the invention can additionally comprise at least one biological and/or cosmetic active agent chosen from moisturizing agents, healing agents, depigmenting agents, UV filters, desquamating agents, antioxidant agents, stimulating active agents the synthesis of dermal and/or epidermal macromoleculars, dermo-contracting agents, antiperspirant agents, soothing agents, anti-aging agents, perfuming agents, anticoagulants, anti-thrombogenic agents, anti-mitotic agents, anti-proliferation, anti-adhesion, anti-migration, cell adhesion promoters, growth factors, antiparasitic molecules, anti-inflammatories, angiogenics, angiogenesis inhibitors, vitamins, hormones, proteins, antifungals, antimicrobial molecules, antiseptics or antibiotics and mixtures thereof. Such active agents are described in particular in FR 1 558 849.

Additional hydrophilic gelling agent

The continuous aqueous phase may also comprise at least one additional hydrophilic gelling agent different from the pH-dependent and/or electrolyte-sensitive hydrophilic gelling agents described above, and preferably endowed with good properties of resistance to electrolytes and/or stability over a wide pH range.

As additional hydrophilic gelling agent, mention may be made of:

• 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, chosen in particular from clays, silicas such as those marketed under the names Aérosil® 90/130/150/200/300/380), 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.

These hydrophilic gelling agents are described in more detail in FR3041251.

Of course, those skilled in the art will take care to choose the possible additional compound(s) and/or their quantity in such a way that the advantageous properties of the dispersion according to the invention are not or substantially not altered by the proposed addition. Also, the person skilled in the art will take care to choose the nature and/or the quantity of additional compound(s) according to the aqueous or fatty nature of the phase considered and/or with regard to the process for manufacturing the dispersion. .

These adjustments are within the general knowledge of those skilled in the art.

Preparation process

A process for forming a biphasic dispersion according to the invention comprises at least the following steps:

(a) disposing, in an intermediate container, of an intermediate dispersion containing an oily phase, in the form of particles (P) and comprising at least one lipophilic gelling agent, dispersed in a continuous aqueous phase comprising at least one hydrophilic gelling agent pH -dependent and/or sensitive to electrolytes and suspensive with respect to particles (P), the oily phase and the aqueous phase being immiscible with each other at ambient temperature and atmospheric pressure,

(b) conditioning the intermediate dispersion of step (a) in a final container,

characterized in that the process comprises, simultaneously with step (b), the addition in the continuous aqueous phase of at least one solution comprising at least one raw material capable of reducing the viscosity of the continuous aqueous phase as it is no longer suspensive vis-à-vis the particles (P).

Intermediate dispersion

An intermediate dispersion according to the invention can be prepared by various methods.

Thus, an intermediate dispersion according to the invention has the advantage of being able to be prepared according to a simple “non-microfluidic” process, namely by simple emulsification.

As in a classic emulsion, an aqueous solution and a fatty solution are prepared separately. For example, it is the addition under agitation of the fatty phase in the aqueous phase which creates the direct emulsion.

The viscosity of the phases, in particular of the continuous phase, and the shear force applied to the mixture are the two main parameters which influence the size and the monodispersity of the particles (P) of dispersed oily phase.

Those skilled in the art will be able to adjust the non-microfluidic process to achieve an intermediate dispersion according to the invention and in particular to satisfy the criteria of diameters of the drops sought.

An intermediate dispersion according to the invention can also be prepared according to a microfluidic process, in particular as described in WO2012/120043, WO2015/055748 or WO2019145424, and described in more detail below.

Advantageously, the intermediate dispersion according to the invention is prepared according to a microfluidic process. Thus, the process for forming a two-phase dispersion according to the invention advantageously comprises at least the following steps:

(a.i) having at least one oily phase comprising at least one lipophilic gelling agent and at least one aqueous phase comprising at least one pH-dependent and/or electrolyte-sensitive hydrophilic gelling agent;

(a.ii) flow, in a circulation conduit, of particles (P) of oily phase in the continuous phase or of a fluid jet formed from the oily phase surrounded concentrically by the aqueous phase towards a mechanical fragmentation device said fluid jet disposed in the vicinity of the outlet of the circulation conduit;

(a.iii) injection of a solution for increasing the viscosity of the continuous aqueous phase into the circulation conduit (38) or at the outlet of the circulation conduit (38), upstream of an intermediate container;

(a.iv) recovery, in the intermediate container, of a dispersion containing the particles (P) in a continuous aqueous phase suspending vis-à-vis the particles (P);

(b.i) injection of at least one solution comprising at least one raw material capable of reducing the viscosity of the continuous aqueous phase, into the circulation conduit (38) or at the outlet of the circulation conduit (38), upstream of a final container, and

(b.ii) recovery, in the final container, of a final dispersion containing the particles (P) in a continuous aqueous phase which does not suspend the particles (P).

FIGS. 2 and 3 illustrate a step (a) 100 of a manufacturing process according to the invention where the manufacturing of the intermediate dispersion 102 relies on a microfluidic device.

There illustrates the manufacture of an intermediate dispersion 102 comprising particles (P) of the sphere or simple capsule type.

There illustrates the manufacture of an intermediate dispersion 102 and of a final two-phase dispersion comprising particles (P) of the complex capsule type. In other words, the illustrates steps (a) 100 and (b) 104 of a manufacturing method according to the invention, and is therefore based on:

- A microfluidic device 30 comprising at least one nozzle 32 for forming drops 12;

- a stage 21 for injecting a solution for increasing the viscosity of the continuous aqueous phase (or solution 62) as described previously;

- an intermediate receptacle 23 for receiving the intermediate dispersion 102;

- a device 31 for simultaneous injection into a final receptacle 33 of the intermediate dispersion 102 and of a solution for reducing the viscosity of the continuous aqueous phase (or solution 63) as described above; And

- A final receptacle 33 for receiving the final two-phase dispersion.

In the case of a dispersion comprising particles (P) of the sphere or simple capsule type (illustrated in ), the forming nozzle 32 comprises at least one internal duct 34 for supplying an internal fluid 36 comprising the first phase 14, and an external circulation duct 38, disposed around the internal duct 34 for supplying and circulating a fluid external 40 forming at least part of the second phase 16.

The apparatus 30 further comprises means 46 for supplying internal fluid 36 into the internal conduit 34, and means 48 for supplying external fluid 40 into the annular space delimited between the internal conduit 34 and the external conduit 38 .

In the example shown in the , the maximum diameter of the conduits 34 and 38 is less than 3 mm to preserve the microfluidic nature of the method.

The internal duct 34 is advantageously arranged coaxially in the external duct 38. It is connected upstream to the supply means 46. It opens downstream by a downstream opening arranged in the external duct 38.

Preferably, the outer conduit 38 delimits with the inner conduit 34 an annular space connected upstream to the supply means 48.

The outer conduit 38 has a downstream opening which is located above and away from the intermediate container 23. It opens into the injection stage 21 of the solution 62.

The supply means 46 and 48 each comprise, for example, a syringe pump, a peristaltic pump or another pressure generating system controlling the flow rate, such as for example a pressure pot coupled with a flow meter and a flow regulation system. debit.

Each of the supply means 46 and 48 is capable of conveying a respective fluid 36 and 40 at a controlled and adjustable flow rate.

In the case of a multiple dispersion comprising particles (P) of the complex capsule type (illustrated in ), the formation nozzle 32 comprises at least one internal duct 34 for supplying an internal fluid 36 comprising the first phase 14, and an intermediate duct 37 for supplying an intermediate fluid 39 intended to form a third phase 19 , arranged around the internal duct 34.

The forming nozzle 32 further comprises an external circulation duct 38, arranged around the internal duct 34 and/or the intermediate duct 37 to supply and circulate an external fluid 40 forming at least part of the second phase 16.

The apparatus 30 further comprises means 46 for supplying internal fluid 36 into the internal duct 34, means 47 for supplying intermediate fluid 39 into the intermediate duct 37, and means 48 for supplying external fluid 40 in the annular space delimited between the internal duct 34 and the external duct 38 (supply means not shown in ).

In the example shown in the , the maximum diameter of the conduits 34, 37 and 38 is less than 3 mm to preserve the microfluidic character of the method.

The internal duct 34 is advantageously arranged coaxially in the external duct 38. It is connected upstream to the supply means 46. It opens downstream by a downstream opening arranged in the external duct 38, set back with respect to the downstream opening. defined by the intermediate duct 37, above this opening.

The intermediate duct 37 extends around the internal duct 34. It preferably delimits with the internal duct 34 an annular space connected upstream to the feed means 47. The intermediate duct 37 emerges through the downstream opening of the intermediate duct 37.

The outer conduit 38 preferably delimits with the intermediate conduit 37 and/or the inner conduit 34 an annular space connected upstream to the supply means 48.

The outer duct 38 has a downstream opening which is located above and away from the container 23. It opens into the viscosity increase stage 21.

The supply means 46, 47 and 48 each comprise, for example, a syringe pump, a peristaltic pump or another pressure generating system controlling the flow rate, such as for example a pressure pot coupled with a flow meter and a flow regulation.

Each of the supply means 46, 47 and 48 is suitable for conveying a respective fluid 36, 39, 40 at a controlled and adjustable flow rate.

According to the invention, the stage 21 comprises at least one pipe 60 for injecting a solution 62, and means 64 for supplying the solution for increasing the viscosity of the continuous aqueous phase 62 into the pipe 60.

For the two variant embodiments of step (a) of the manufacturing process described above, stage 31 comprises at least one pipe 60 for injecting a solution 62, and supply means 64 for the solution 62 in conduit 60.

In the example shown in the , stage 21 comprises a conduit 60 peripheral injection of the solution 62.

The peripheral duct 60 extends at the periphery of the external circulation duct 38, parallel, and in the present case coaxially, with the local axis of the external duct 38. The downstream opening of the external duct 38 extends into the duct device 60.

The peripheral duct 60 defines, downstream of the downstream opening of the external duct 38, a dispensing opening which opens into the container 23 or above the latter.

Preferably, the peripheral duct 60 delimits, with the external duct 38, an annular space which opens upstream of the distribution opening of the peripheral duct 60.

Preferably, the peripheral duct 60 is configured to allow the injection of the solution 62 coaxially with the axis of circulation of the dispersion containing the drops 12 and the second phase 16, just at the outlet of the external circulation duct 38.

In this example, the peripheral duct 60 is suitable for collecting the drops 12 and the second phase 16 into which the solution 62 has been introduced, and for conveying them to the distribution opening of the peripheral duct 60.

The supply means 64 includes a tank 68 (not shown) containing the solution 62 (not shown).

The supply means 64 comprises for example a syringe pump, a peristaltic pump or another pressure generating system controlling the flow rate, such as for example a pressure pot coupled with a flow meter and a flow control system.

The intermediate container 23 is arranged below the dispensing opening of the peripheral conduit 60.

Preferably, the intermediate container 23 can be represented by a seal, a filling syringe, a filling hopper or an IBC container (“Intermediate bulk container”, also referred to interchangeably as an IBC container (“Large Bulk Container”).

As a variant, it contains a volume of liquid intended to form part of the second phase 16, advantageously an external volume of fluid 40.

Then, the intermediate dispersion 102 is moved to the intermediate container 23.

Initially, the internal fluid 36 is prepared so as to form the first phase 14. The first phase 14 comprises at least one oil, at least one lipophilic gelling agent, in particular heat-sensitive, and optionally at least one first polymer precursor of the coacervation. The precursor polymer is lipophilic, and advantageously cationic.

Initially, the outer fluid 40 is prepared to form the second phase 16. The outer fluid 40 comprises at least water, at least one pH-dependent and/or electrolyte-sensitive hydrophilic gelling agent, and optionally at least one second precursor polymer of the coacervation, here a water-soluble polymer, for example of the anionic type.

For obvious reasons, the steps of mixing the constituent compounds of the first phase and of the second phase are carried out under suitable conditions to form fluid phases compatible with the microfluidic method according to the invention. In particular, and if necessary, the step of mixing the constituent compounds of the first phase is carried out hot, and in particular at a temperature of between 60 and 100°C, preferably between 70 and 90°C. This is particularly the case when a phase comprises at least one heat-sensitive gelling agent.

Advantageously, the internal fluid 36 and/or the external fluid 40 can also comprise at least one additional compound as defined above.

An aqueous solution 62 for increasing the viscosity of the second phase 16 (or continuous phase) is also prepared. It contains a base, in particular an alkali hydroxide, such as sodium hydroxide.

Then, the internal fluid 36 and the external fluid 40 are placed respectively in the respective supply means 46 and 48.

The solution 62 is placed in the supply means 64.

Then, the supply means 46, 47 (optional), 48 and 64 are activated.

The internal fluid flow 36 circulating in the internal conduit 34 enters coaxially into the conduit 38 at the level of the downstream opening of the internal conduit 34.

Internal fluid 36 is then surrounded by external fluid 40 in external conduit 38.

At the level of the downstream opening of the internal conduit 34, drops 12 of internal fluid 36, surrounded by a film of external fluid 40, are formed.

The drops 12 then circulate in the external fluid 40 towards the downstream opening of the external duct 38.

As indicated previously, it is then necessary to increase the viscosity of the external fluid 40, after formation of the drops 12 in particular to ensure satisfactory suspension of the drops in the external fluid 40. Similarly, the pH of the external fluid 40 is neutralized.

The increase in viscosity and the possible neutralization occur near the dispensing opening of the peripheral duct 60, just before the introduction of the dispersion into the intermediate container 23.

Thus, the drops 12 stabilized in the external fluid 40, arrive in the stage 31.

The solution 62 is then injected coaxially with the flow of drops 12 in the external fluid 40, at the periphery of the external fluid 40. The solution 62 diffuses into the external fluid 40 during its transport through the downstream part of the peripheral conduit 60.

The diffusion time of the viscosity-increasing solution 62 in the continuous phase 16 is very short, given the small thickness to be traversed. The continuous phase 16 almost immediately acquires a suspensive character when it is collected in the container 23.

The intermediate dispersion 102 thus obtained is ejected at the outlet of the peripheral duct 60, at the level of the distribution opening of the peripheral duct 60.

The intermediate dispersion 102 is then packaged in the intermediate container 23 where the drops 12 of first phase 14 remain suspended in the second phase 16 formed by the external fluid 40 and the solution 62.

In the embodiment illustrated in , the device 30 comprises a plurality of nozzles 32, all connected downstream to a common stage 21, the nozzles 32 being arranged in parallel above an intermediate container 23. The nozzles 32 are offset laterally with respect to the stage 21. A collection circuit makes it possible to collect the drops 12 in the fluid 40 at the outlet of each nozzle 32 in order to collect them and introduce them into the stage 21. In the , stage 21 comprises a central duct 60 for injecting solution 62.

According to an embodiment not illustrated, step (a) is based on a microfluidic process as described in WO2019145424, namely where the formation of the particles (P) is carried out by means of a nozzle capable of conveying a fluid jet formed of a second fluid concentrically surrounding a first fluid and a mechanical fragmentation device of said fluid jet arranged in the vicinity of the outlet of the nozzle.

Final dispersal

As indicated above, it is then necessary to reduce the viscosity of the external fluid 40 simultaneously with the step of packaging it in the final container 33, to access a continuous aqueous phase that does not suspend the drops, and preferably without modifying significantly the pH of the external fluid 40.

The packaging of the intermediate dispersion 102 in a final container can be carried out by means of any suitable device known to those skilled in the art and of course compatible with the intermediate container 23 considered.

Such a device can for example be represented by:

- a suction pipe which is immersed in or connected to the intermediate container 23;

- a filling hopper, optionally fluidically connected to a filling nozzle,

said device being necessarily adapted to ensure, in the final container, simultaneous packaging in intermediate dispersion 102 and in solution 63.

Step (b) 104 of the manufacturing method according to the invention illustrated in includes as follows:

- a device 31 for simultaneous injection into the final container of the intermediate dispersion 102 and of a solution for reducing the viscosity of the continuous aqueous phase (or solution 63) as described previously;

- a supply means 74 of the solution 63 (not shown) at the level of the device 31; And

- A final receptacle 33 for receiving the final two-phase dispersion.

The device 31 illustrated in is limited to describing a circulation conduit 108 of the intermediate dispersion 63 comprising at least one injection conduit 106 of the solution 63.

In the example shown in the , the circulation duct 108 comprises a peripheral duct 106 and a central duct 106 for injecting the solution 63.

Preferably, the conduit 106 is configured to allow the injection of the solution 63 coaxially with the axis of circulation of the intermediate dispersion 102.

An aqueous solution 63 comprising at least one raw material capable of reducing the viscosity of the continuous aqueous phase of the intermediate dispersion 23 is also prepared. The solution 63 is placed in the supply means 74 (not shown). The feed means 74 comprises for example a syringe pump, a peristaltic pump or another pressure generating system controlling the flow rate, such as for example a pressure pot coupled with a flow meter and a flow control system. The supply means 74 includes a reservoir containing the solution 63 (not shown).

The final container 33 is placed below the dispensing opening of the circulation conduit 108.

Preferably, the final container 33 can be represented by a packaging or primary packaging, namely the dedicated container to be sold and used/handled by the user or the final consumer.

Then, the supply means 74 is activated.

The intermediate dispersion 102 is then moved towards the downstream opening of the circulation conduit 108. The intermediate dispersion 102 is then mixed with the solution 63 in the circulation conduit 108.

According to an advantageous embodiment, the conduit 108, at the outlet of the injection conduit 106, comprises any device suitable for reinforcing the homogeneity of the mixture between the intermediate dispersion 102 and the solution 63, such as for example a static mixer.

The solution 63 is then injected coaxially with the intermediate dispersion flow 102. The solution 63 diffuses into the external fluid 40 during its transport through the downstream part of the peripheral conduit 106.

The diffusion time of the solution 63 is very short, given the small thickness to be passed through. The continuous phase 16 almost immediately acquires a non-suspensive character when it is collected in the container 33.

The reduction in viscosity preferably occurs near the dispensing opening of conduit 108, preferably just before the introduction of the final dispersion into the final container 33.

The final dispersion thus obtained is ejected at the outlet of conduit 108, at the level of the distribution opening of conduit 108.

The final dispersion falls into the final container 33 through a volume of air and the drops 12 of first phase 14, in the second phase 16 formed by the external fluid 40, the solution 62 and the solution 63, then undergo the phenomenon of phase shift described above.

The injection of the solution 63 is therefore carried out in a minimally invasive manner, and directly in line with the packaging of the intermediate dispersion 102 in the final container 33.

A manufacturing method according to the invention is therefore advantageous at least for the following reasons:

The injection of solution 62 is therefore carried out in a minimally invasive manner, and directly in line with the manufacture of drops 12.

This guarantees the use of an aqueous phase that is sufficiently fluid to allow adequate formation of drops 12 at the nozzle 32 while guaranteeing a robust drop manufacturing process. The intermediate dispersion 102 thus comprises a continuous suspending aqueous phase, without harming the stability of the drops 12 formed, and via a simple, safe and inexpensive manufacturing process.

The intermediate dispersion 102 can therefore be stored in a stable manner in the intermediate container 23 over an extended period of time, for example several days to several months, in order to then carry out its packaging in the final container and its concomitant transformation into a two-phase dispersion, without replacement of the continuous aqueous phase.

The method according to the invention limits the shear. No force is generated to deform or fragment drops 12 when solution 62 and solution 63 are injected.

In the final dispersion, the drops 12 thus formed are therefore stable and do not tend to coalesce on each other or to aggregate together and/or to adhere to the walls of the final container, despite the nonsuspensive nature of the aqueous phase continues.

The manufacturing process according to the invention is therefore particularly effective for forming, in a simple, robust and particularly controlled manner, a two-phase composition in the form of a dispersion, one of the phases of which is in the form of macroscopic drops which remain stable despite the presence of a non-suspensive continuous aqueous phase, which moreover without resorting to the use of surfactants.

Uses

Preferably, a dispersion according to the invention can be used directly, at the end of the aforementioned preparation processes, as a composition, in particular a cosmetic composition.

The invention also relates to the use of a dispersion 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, in particular for caring for and/or making up a keratin material, in particular the skin and/or the hair, and more particularly the skin, comprising at least one dispersion according to invention, optionally in combination with at least one physiologically acceptable medium.

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

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

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 aqueous continuous phase as described above.

In the context of the invention, and unless otherwise stated, the term “physiologically acceptable medium” means a medium suitable for cosmetic applications, and suitable in particular for the application of a composition of the invention to a keratin material, in particular the skin and/or the hair, and more particularly 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, a dispersion 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 a step of applying to the said keratin material at least one dispersion or of at least one aforementioned cosmetic composition.

The present invention also relates to the use of a dispersion 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.

Specific examples of implementation of the method according to the invention to obtain dispersions 10 will now be described.

EXAMPLES

Example 1 : manufacturing process according to the invention with or without amodimethicone

This example illustrates the process for manufacturing and packaging a two-phase dispersion according to the invention.

The composition of the phases (fluids) and parameters of the manufacturing process are described in the tables below.

Table 1: composition of the continuous phase original (OF) Name Supplier INCI name % w/w Phases AQUEOUS PHASE (OF) subtotal 100 OSMOTIC WATER / AQUA QSP* PURECARE CHP XO UNILAB CHLORPHENESIN 0.30 PENTIOL GREEN+ / A-LEEN 5 MINASOLVE PENTYLENE GLYCOL, AQUA 3.55 CREMERGLYC REFINED GLYCERINE 99.5% - RAPESEED CREAM OLEO GLYCERIN, AQUA 7.10 MAKILENE GC DAITO KASEI BUTHYLENE GLYCOL 4.73 UNITAMURON H-22 INDUCHEM AQUA, PENTYLENE GLYCOL, TAMARINDUS INDICA SEED GUM 3.54 CARBOPOL ULTREZ 10 POLYMER LUBRIZOL CARBOMER 0.14 CARBOPOL ETD 2050 POLYMER LUBRIZOL CARBOMER 0.07 10% NAOH SOLUTION / SODIUM HYDROXIDE 0.12

* QSP: sufficient quantity for.

Table 2: composition of the dispersed oily phase (IF) Essay AT B VS Name Supplier INCI name % w/w Phases FAT PHASE (IF) subtotal 100 100 100 CETIOL C 5C [MB] BASF COCO-CAPRYLATE/CAPRATE, TOCOPHEROL QSP* QSP* QSP* EMC30 PolymerExpert AQUA, CAPRYLIC/CAPRIC TRIGLYCERIDE, CASTOR OIL/IPDI COPOLYMER 33.33 33.33 33.33 SUNSHINE SOFT BRONZE [C84-6080] SUNCHEMICAL Synthetic Fluorphlogopite, CI 77491 0.12 0.12 0.12 NIKKOL MEADOWFOAM OIL NIKKO CHEMICALS LEMNANTHES ALBA SEED OIL, TOCOPHEROL 20.00 20.00 20.00 CAS-3131 NUSIL TECHNOLOGY LLC AMODIMETHICONE 0 0.10 0.20

Table 3: solution for increasing the viscosity of the continuous phase (BP) Name Supplier INCI name %w/w OSMOTIC WATER / AQUA QSP* 10% NAOH SOLUTION PANREAC QUIMICA SLU SODIUM HYDROXIDE 4.36 Total 100.00

Table 4: Continuous phase viscosity reduction solution ( AT F) Name Supplier INCI name %w/w OSMOTIC WATER / AQUA QSP* SOLUTION 10% CITRIC ACID ANHYDROUS PRS CODEX PANREAC QUIMICA SLU CITRIC ACID 15.95 10% NAOH SOLUTION PANREAC QUIMICA SLU SODIUM HYDROXIDE 8.17 Total 100.00

Optionally, the AF solution may also comprise at least one preservative, for example PENTIOL GREEN+ / A-LEEN 5 from MINASOLVE (INCI: PENTYLENE GLYCOL, AQUA), preferably at 5% by weight relative to the weight of the solution of AF.

Preparation protocol:

For OF: Chlorphenesin and Pentylene glycol are incorporated into the water. The mixture is stirred for 5 min. The carbomers are then dispersed in the above mixture with stirring for 30 minutes using a deflocculating blade. The glycerin is then added and the mixture is stirred for 10 min. Makilene GC, Natrlquest E30 and Unitamuron H-22 are then added and the mixture is placed under stirring until homogenization. The sodium hydroxide is then added and the solution is mixed for 10 minutes.

For the FI:

Amodimethicone (when present) is added to CETIOL C 5C then mixed using a magnetic bar for 5 min. Next, NIKKOL MEADOWFOAM OIL, EMC30 and SUNSHINE SOFT BRONZE [C84-6080] are added with stirring at 80°C until homogenization.

For BP and AF : their respective preparation falls within the general skills of a person skilled in the art.

Manufacturing process :

The intermediate dispersion is obtained by implementing a "microfluidic" process, in particular as described in WO2017046305. The process parameters, in particular the flow rates and the temperature of the phases are given in table 5 below.

Table 5: Parameters of the microfluidic process

%phases in PF Temperature (in °C) IF 6 80 OF 84.60% 80 BP 4.70% YOUR** AF 4.70% YOUR**

** : Ambient temperature

The intermediate dispersion obtained after injection of the solution for increasing the viscosity of the continuous phase (BP) is stored in a seal for 1 month. The pH of this intermediate dispersion is 5.5.

Then, this intermediate dispersion is packaged in a final 50 ml glass packaging simultaneously with the solution for reducing the viscosity of the continuous phase (AF) according to the parameters described in table 5 above. The pH of this final dispersion is 5.84.

Parameters observed:

At the end of the manufacture of the two-phase dispersions, we observe (1) the phase shift kinetics, (2) the aggregation of drops between them, (3) the adhesion of the drops to the packaging, (4) the transparency of the continuous phase and (5) the mechanical resistance of the drops over time after at least 20 sequences of agitation then return to rest and phase shift.

Table 6: Scoring criteria:

RATING CRITERIA 0 1 2 3 Aggregation of drops Lack of aggregation Slight aggregation Average aggregation Strong aggregation Adhesion of the drops to the packaging No Membership Slight adhesion Average Membership Strong adherence Continuous phase transparency Transparent Slight haze medium trouble strong disorder Mechanical resistance of drops Very good Good Mean Bad

Table 7 Results : Average particle diameter
(in microns) Phase shift Aggregation of drops Adhesion of the drops to the packaging Continuous phase transparency Mechanical resistance of drops Dispersion 1A 890 Homogeneous creaming in 3 minutes 1 1 2 1 Scatter 1B 890 Homogeneous creaming in 3 minutes 0 0 1 0 Dispersion 1C 890 Homogeneous creaming in 3 minutes 0 1 1 1

*** RAS: Nothing to report

The manufacturing method according to the invention therefore provides simple and robust access to biphasic compositions in the form of a dispersion, one of the phases of which is in the form of macroscopic drops, including when said dispersion is at rest.

The presence of amodimethicone in the dispersed phase at a suitable content, and therefore of a membrane at the level of the particles (P), makes it possible to improve the phenomena of non-aggregation of the drops between them, of non-adhesion of the drops to the walls internal packaging, and the mechanical resistance of the drops over time.

Example 2 : impact of the raw material capable of reducing the viscosity of the continuous aqueous phase.

Unless otherwise indicated, the phases (fluids) and the parameters of the manufacturing process are identical to those described in example 1. The IF used in example 2 is IF B presented in table 2 above.

Painting 8 : composition of the original continuous phase (OF) Name Supplier INCI name % w/w Phases OF1 OF2 AQUEOUS PHASE (OF) subtotal 100 Osmotic water / Aqua QSP* QSP* Purecare CHP XO Unilab Chlorphenesin 0.32 0.32 Pentiol green+ / A-Leen 5 Minasolve Pentylene glycol, aqua 3.58 3.58 Cremerglyc refined glycerine 99.5% - rapeseed Cream oleo Glycerin, aqua 7.17 7.17 Makilene GC daito kasei Butylene glycol 4.78 4.78 Unitamuron H-22 Induchem Aqua, pentylene glycol, tamarindus indica seed gum 3.58 3.58 Carbopol ultra 21 polymer Lubrizol ACRYLATES/C10-30 ALKYL ACRYLATE CROSSPOLYMER 0.09 0 Carbopol ETD 2050 Polymer Lubrizol CARBOMER 0.12 0 Carbopol ultra 10 polymer Lubrizol CARBOMER 0 0.13

* QSP: sufficient quantity for.

Painting 9 : continuous phase viscosity reduction solution ( AT F) Name Supplier INCI name D E F G H %w/w %w/w %w/w %w/w %w/w Osmotic water / Aqua QSP* CALCIUM CHLORIDE 2-HYDRATE POWDER ? Calcium chloride 0.57 - - - - Solution 10% citric acid anhydrous prs codex Panreac Quimica Slu citric acid - 15.96 - - - Glypure™ 70 The Chemours Company FC, LLC Glycolic acid (70%) - - 2.18 - - Ronacare® salicylic acid extra pure Merck KGAA salicylic acid - - - 2,033 - Natrlquest E30 Innospec Aqua, trisodium ethylenediamine disuccinate - - - - 3.23 10% NaOH solution Panreac quimica slu Sodium hydroxide 10 8.17 8.42 6.69 0 Total 100.00 100.00 100.00 100.00 100.00 OF associated OF1 OF1 OF1 OF1 OF2

The preparation protocols for the different phases are identical to those described in Example 1.

Parameters observed:

At the end of the manufacture of the two-phase dispersions, we observe (1) the phase shift kinetics, (2) the aggregation of drops between them, (3) the adhesion of the drops to the packaging, (4) the transparency of the continuous phase and (5) the mechanical resistance of the drops over time after at least 20 sequences of agitation then return to rest and phase shift.

Table 10 Scoring criteria:

RATING CRITERIA 0 1 2 3 Aggregation of drops Lack of aggregation Slight aggregation Average aggregation Strong aggregation Adhesion of the drops to the packaging No Membership Slight adhesion Average Membership Strong adherence Continuous phase transparency Transparent Slight haze medium disorder strong disorder Mechanical resistance of drops Very good Good Mean Bad

Table 11 Results : Average particle diameter
(in microns) Phase shift Aggregation of drops Adhesion of the drops to the packaging Continuous phase transparency Mechanical resistance of drops Scatter D 890 Homogeneous creaming 0 1 2 1 Scatter E 890 Homogeneous creaming 0 0 1 1 F-scatter 890 Homogeneous creaming 0 1 1 1 G-scatter 890 Homogeneous creaming 0 0 1 1 H-scatter 890 Homogeneous creaming 0 0 0 0

The manufacturing process according to the invention allows access to biphasic dispersions by means of salts, acids or chelating agent.

In view of the performances observed in terms of transparency of the continuous phase, acids and chelating agents are preferred, and most particularly chelating agents.

Claims (21)

A method of forming a biphasic dispersion, said method comprising at least the following steps:
(a) disposing, in an intermediate container, of an intermediate dispersion containing an oily phase, in the form of particles (P) and comprising at least one lipophilic gelling agent, dispersed in a continuous aqueous phase comprising at least one hydrophilic gelling agent pH -dependent and/or sensitive to electrolytes and suspensive with respect to particles (P), the oily phase and the aqueous phase being immiscible with each other at ambient temperature and atmospheric pressure,
(b) conditioning the intermediate dispersion of step (a) in a final container,
characterized in that the process comprises, simultaneously with step (b), the addition in the continuous aqueous phase of at least one solution comprising at least one raw material capable of reducing the viscosity of the continuous aqueous phase as it is no longer suspensive vis-à-vis the particles (P). Process according to Claim 1, in which the particles (P) having a diameter greater than or equal to 100 μm represent a volume greater than or equal to 60% of the total volume of the dispersed oily phase and/or at least 60% of the particles (P ) have a diameter greater than or equal to 100 μm. Process according to any one of Claims 1 to 2, in which the final dispersion obtained in stage (b) comprises between 1% and 40%, preferably between 2% and 25%, preferentially between 3% and 15%, and in in particular between 4% and 10%, by weight of particles (P) relative to the total weight of said final dispersion. A method according to any preceding claim, wherein said method comprises at least the following steps:
(ai) having at least one oily phase comprising at least one lipophilic gelling agent and at least one aqueous phase comprising at least one pH-dependent and/or electrolyte-sensitive hydrophilic gelling agent;
(a.ii) flow, in a circulation conduit, of particles (P) of oily phase in the continuous phase or of a fluid jet formed from the oily phase surrounded concentrically by the aqueous phase towards a mechanical fragmentation device said fluid jet disposed in the vicinity of the outlet of the circulation conduit;
(a.iii) injection of a solution for increasing the viscosity of the continuous aqueous phase into the circulation conduit or at the outlet of the circulation conduit, upstream of an intermediate container;
(a.iv) recovery, in the intermediate container, of an intermediate dispersion containing the particles (P) in a continuous aqueous phase suspending vis-à-vis the particles (P);
(bi) simultaneous injection, into a final container, of at least one intermediate dispersion and of a solution comprising at least one raw material capable of reducing the viscosity of the continuous aqueous phase, and
(b.ii) recovery, in the final container, of a final dispersion containing the particles (P) in a continuous aqueous phase which does not suspend the particles (P). Process according to any one of the preceding claims, in which the continuous aqueous phase of the intermediate dispersion of step (a) has a viscosity greater than or equal to 3000 mPa.s, preferably greater than or equal to 5000 mPa.s, better is between 3000 mPa.s and 10000 mPa.s, and in particular is between 4000 mPa.s and 6000 mPa.s. Process according to any one of the preceding claims, in which the continuous aqueous phase of the final dispersion of step (b) has a yield value of less than 2 Pa, preferably less than 1 Pa. Process according to any one of the preceding claims, in which the particles (P) are:
- spheres; and or
- capsules, preferably comprising a liquid core or at least partly gelled or at least partly thixotropic. Process according to the preceding claim, in which the sphere or the core of the capsules is monophasic and/or comprises an intermediate drop of an intermediate phase, said intermediate drop comprising at least one internal drop of an internal phase. Process according to any one of Claims 7 or 8, in which the capsules comprise a gelled envelope or a shell completely encapsulating the said core, preferably a shell comprising at least one gelled polyelectroyte, at least one polymer, or deriving from a reaction of complex coacervation between at least one anionic polymer, preferably hydrophilic, and at least one cationic polymer, preferably lipophilic. Process according to any one of the preceding claims, in which the dispersion further comprises a third phase, aqueous and/or oily, in the form of particles (P'), different from the particles (P), dispersed in the continuous aqueous phase, and preferably comprising a density identical to that of the continuous aqueous phase. Process according to any one of the preceding claims, in which the pH-dependent and/or electrolyte-sensitive hydrophilic gelling agent is chosen from copolymers of acrylic acid or maleic acid and other monomers, such as acrylamide , alkyl acrylates, C5-C8 alkyl acrylates, C10-C30 alkyl acrylates, C12-C22 alkyl methacrylates, methoxypolyethylene glycol methacrylates, hydroxyester acrylates, crosspolymer acrylates , and mixtures thereof, and preferably is an optionally crosslinked poly(acrylic acid) (or carbomer). Process according to any one of the preceding claims, in which the lipophilic gelling agent is chosen from organic or inorganic, polymeric or molecular lipophilic gelling agents; fatty substances that are solid at ambient temperature and pressure; and mixtures thereof, and preferably is a heat-sensitive lipophilic gelling agent. Process according to any one of the preceding claims, in which the raw material capable of reducing the viscosity of the continuous aqueous phase is chosen from water, at least one salt, at least one acid, at least one chelating agent, and their mixtures. Process according to the preceding claim, in which:
- the salt is chosen from mineral salts, preferably a chloride salt, and in particular chosen from calcium chloride, sodium chloride;
- the acid is chosen from an aminopolycarboxylic acid, citric acid, salicylic acid, glycolic acid, lactic acid, malic acid, tartaric acid, acetic acid, acetylsalicylic acid , ascorbic acid, hydrochloric acid, sulfuric acid, nitric acid, formic acid, preferably citric acid;
- the chelating agent is a chelating agent comprising at least one cation, preferably is chosen from ethylenediaminedisuccinic acid (EDDS), ethylenediaminetetraacetic acid (EDTA) or Trisodium Ethylenediamine Disuccinate; And
- their mixtures. Process according to any one of the preceding claims, in which the continuous aqueous phase of the final dispersion comprises between 0.01% and 1%, preferably between 0.02% and 0.75%, and better still between 0.03% and 0.5%, by weight of raw material(s) capable of reducing the viscosity of the continuous aqueous phase of the intermediate dispersion relative to the total weight of the continuous aqueous phase of the final dispersion. Process according to any one of the preceding claims, in which the mass ratio between the continuous aqueous phase of the intermediate dispersion and the solution comprising at least one raw material capable of reducing the viscosity of the continuous aqueous phase is between 80/20 and 99/1, and better between 90/10 and 95/5. A method according to any preceding claim, wherein the intermediate container is a bucket, fill syringe, fill hopper, or IBC container (or bulk container). Method according to any one of the preceding claims, in which the final container corresponds to the packaging or primary packaging. A method according to any preceding claim, wherein the dispersion does not include a surfactant. Composition, in particular cosmetic, comprising a dispersion according to any one of Claims 1 to 19, optionally in combination with a physiologically acceptable medium. 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 a step of applying to the said keratin material a dispersion according to any one of Claims 1 to 19 or a cosmetic composition according to claim 20.