FR3126308A1 - SUSPENSION OF FAT PHASE BEADS IN AN AQUEOUS SURFACTANT GEL - Google Patents

Abstract

The present invention relates to a method for preparing a suspension of fatty phase beads in an aqueous surfactant gel. The invention also relates to a suspension of fatty phase beads in an aqueous surfactant gel, in particular obtained by the process of the present invention, as well as its use as a cosmetic composition suitable, in particular, for cleaning keratin fibres.

Description

SUSPENSION OF FAT PHASE BEADS IN AN AQUEOUS SURFACTANT GEL

FIELD OF THE INVENTION

The present invention relates to a method for preparing a suspension of fatty phase beads in an aqueous surfactant gel.

The invention also relates to a suspension of fatty phase beads in an aqueous surfactant gel, in particular obtained by the process of the present invention, as well as its use as a cosmetic composition suitable, in particular, for cleaning keratin fibres.

STATE OF THE ART

The search for new textures with the aim of improving the sensory properties of cosmetic products has been widely developed in recent years.

Among these new textures, the encapsulation and dispersion in an aqueous phase of the fatty phase in the form of macroscopic drops or beads, allowing the delivery of a lipophilic active ingredient in an aqueous formula, is enjoying growing success among consumers.

This type of texture requiring the presence of drops or beads visible to the naked eye is difficult to access by a conventional emulsification process leading to the formation of very fine droplets having a diameter of the order of 0.1 to 100 μm in depending on the fineness of the emulsion.

It is known in the prior art that these textures are often obtained in several stages, the beads of oil or fatty phase being manufactured beforehand by a separate process and then suspended in the aqueous phase. However, several drawbacks are associated with the use of pre-made beads. In particular, specific development will be necessary depending on the need and the options desired in the finished product (active ingredient, color, etc.). If we add to this the transport of the prefabricated beads requiring special precautions to be taken to ensure the integrity and quality of the beads as well as a stage of filtration and rinsing of the beads before use, the process for manufacturing the suspensions of beads is finally complex and the associated cost is particularly high.

For example, patents FR3071730, FR2972367 and FR2976824 and application WO2012120043 relating to dispersions of macroscopic drops of fatty phase in an aqueous phase are known, the dispersions being obtained by a microfluidic process, making it possible to obtain monodisperse and macroscopic drops whose size can vary between 1000 µm and 2000 µm. In particular, in order to give the drops obtained a good resistance and prevent their coalescence, these contain a shell, formed by coacervation of polymers of opposite charges, providing a certain rigidity to the drops produced and therefore an appearance and a texture which are not very pleasant for the consumer.

Another difficulty arises when cleaning formulas containing oil balls in suspension are desired. Indeed, with the addition of foaming surfactants in the composition, a risk of interaction between the different ingredients may occur, for example between the gelling agents and the surfactants, which may have a negative impact on the viscosity, the transparency or even the suspension of the oil balls. In addition, the presence of surfactant, by lowering the surface tension of water, can promote the solubilization and emulsification of part of the fatty phase in the aqueous phase, thus leading to a reduction in the size of the beads but also to a loss of transparency due to emulsification.

Thus, there is a need for a process allowing the in situ formation of beads of macroscopic fatty phase, devoid of shell or protective membrane and being in suspension in an aqueous phase containing surfactants, without emulsifying the two phases. Indeed, an emulsification of the two phases could lead to the formation of very small beads of fatty phase, of the order of 0.1 to 100 μm, giving an opaque white appearance to the final product. The process implemented must also be reproducible on an industrial scale, without deterioration of the beads obtained in situ due to the shearing that the beads could undergo during their manufacture.

The present invention therefore aims to provide a method for preparing a suspension of beads of fatty phase in an aqueous surfactant gel, comprising an aqueous phase, comprising at least one gelling agent and / or thickening agent of aqueous phase and at least one agent surfactant; and a fatty phase in the form of gelled beads, obtained in situ , in suspension in the aqueous phase and comprising at least one fatty phase gelling and/or thickening agent and at least one fatty substance.

Advantageously, the method according to the present invention allows the in situ manufacture of beads of fatty phase, as well as a scale-up without emulsification of the fatty phase in the aqueous phase, thus leading to a stable suspension, that is to say exhibiting no creaming, sedimentation or aggregation of the beads of fatty phase between them, as well as the absence of opacification of the aqueous phase due to the emulsification of part of the fatty phase in the aqueous phase. Due to the in situ manufacture of the beads, another advantage of the process according to the present invention is to make it possible to formulate beads directly adapted to the desired characteristics of each finished product (active ingredients, color, etc.), while reducing the costs of production and transportation.

SUMMARY

The invention relates to a method for preparing a suspension of fatty phase beads in an aqueous surfactant gel, comprising the following steps:

1. in a first reactor, mixing, at a temperature between 30° C. and 130° C., at least one fatty phase gelling and/or thickening agent and at least one fatty substance;
2. in a second reactor, mixture of formulation water and at least one aqueous phase gelling and/or thickening agent;
3. agitation of the fluid mixture obtained in step b) until a vortex is obtained and maintenance of the vortex by constant agitation of the mixture obtained;
4. slow addition of the mixture obtained in step a) into the center of the vortex formed in step c) allowing the production of gelled beads of fatty phase having an average diameter greater than 300 μm;
5. addition of the mixture obtained in step d) in an aqueous solution comprising at least one surfactant and homogenization with slow stirring; And
6. adjusting the pH of the mixture obtained in step e) to a pH between 4.0 and 11.0 and homogenizing the mixture obtained with slow stirring.

According to one embodiment, the mixture obtained in step a) is heated to a temperature of between 70°C and 95°C, preferably between 80°C and 90°C.

According to one embodiment, the fatty phase gelling and/or thickening agent is chosen from gelling agents and/or lipophilic organic or mineral thickeners, waxes that are solid at room temperature, butters or a mixture thereof.

According to one embodiment, the fatty phase gelling and/or thickening agent is present in an amount ranging from 0.01% to 10% by weight relative to the total weight of said suspension.

According to one embodiment, the fatty substance is chosen from alkanes, fatty alcohols, fatty acids, fatty acid esters, fatty alcohol esters, triglycerides, oils such as mineral oils, vegetable oils, non-silicone animal and synthetic waxes, non-silicone waxes, silicones, pasty fatty substances or butters or a mixture thereof.

According to one embodiment, the fatty substance is present in an amount ranging from 0.1% to 10% by weight relative to the total weight of said suspension.

According to one embodiment, the aqueous phase gelling and/or thickening agent is chosen from synthetic anionic gelling and/or thickening agents such as carbomers, sodium polyacrylate, copolymers of acrylic or methacrylic acid, copolymers of acrylic or methacrylic acid and a C ₁ -C ₃₀ alkyl acrylate or methacrylate, modified sulfonated acrylic acid copolymers, associative acrylic polymers or copolymers or a mixture thereof.

According to one embodiment, the aqueous phase gelling and/or thickening agent is present in an amount ranging from 0.1% to 5.0% by weight relative to the total weight of said suspension.

According to one embodiment, the surfactant is chosen from cationic, anionic, nonionic, amphoteric, zwitterionic surfactants or a mixture thereof.

According to one embodiment, the surfactant is present in an amount ranging from 1% to 30% by weight relative to the total weight of said suspension.

According to one embodiment, during step f), the pH of the mixture obtained in step e) is adjusted to a pH ranging from 4.5 to 7.0.

The invention also relates to a suspension of fatty phase beads in an aqueous surfactant gel, comprising:

an aqueous phase comprising:

• at least one aqueous-phase gelling and/or thickening agent;
• at least one surfactant; And

a fatty phase in the form of gelled beads suspended in the aqueous phase, comprising:

• at least one fatty phase gelling and/or thickening agent; And
• at least one fatty substance.

In one embodiment, the beads of fatty phase have an average diameter greater than 300 μm.

According to one embodiment, the suspension according to the present invention is obtained and/or capable of being obtained by the method of the present invention.

According to one embodiment, the surfactant is present in an amount ranging from 1% to 30% by weight relative to the total weight of said suspension.

According to one embodiment, the suspension according to the invention has a viscosity ranging from 500 mPa.s to 50,000 mPa.s.

According to one embodiment, the suspension according to the invention has a pH ranging from 4.0 to 11.0.

DEFINITIONS

In the present invention, the terms below are defined as follows:

The term "comprise" and its variations should be understood according to the present invention as not excluding the presence of other steps and/or components. In some embodiments, the term comprise may be interpreted as "consisting essentially of".

The term “gel” relates to a homogeneous, isotropic, rigid, vibrating and elastic medium. A gel is a three-dimensional network of dilute solids in a fluid that exhibit no flow when in a steady state. In bulk, gels are mainly made up of liquid, but have a behavior close to that of solids thanks to their entangled three-dimensional network within the liquid. It is these tangles that give gels their structure and contribute to their adhesion.

The terms "gelling agent" and "thickening agent" relate to ingredients capable of modifying the rheology and increasing the viscosity of a liquid composition. The "gelling agents" and/or "thickener" are of terrestrial vegetable origin (carob), marine vegetable (alginate), animal (gelatin), biofermentative (xanthan), mineral (silica, salts), synthetic (carbomer), and all confer specific sensory characteristics that can be combined by associating them in the composition. Non-exhaustively, the thickening agents can also include all combinations of raw materials making it possible to increase the viscosity of the aqueous system, such as combinations of surfactants. Non-limiting examples of these combinations of surfactants include the combination of surfactants from the family of isethionates, alkyl betaines, alkylpolyglusides and alkanolamide. These gelling and/or thickening agents must give the system suspensive properties allowing a homogeneous distribution of the beads of fatty phase in a lasting manner.

The term "fat" refers to a substance composed of molecules with hydrophobic properties. A fatty substance is in the liquid, semi-solid or solid state at room temperature and is insoluble in water. Fats can be of animal, vegetable, mineral or synthetic origin. Within the meaning of the invention, the fatty substance is chosen from alkanes, fatty alcohols, fatty acids, fatty acid esters, fatty alcohol esters, synthetic triglycerides, oils such as mineral oils, non-silicone vegetable, animal and synthetic oils, non-silicone waxes, silicones.

The term "surfactant" in the context of the present invention relates to water-soluble substances having the particularity of aggregating at the interfaces between water and fatty substances and therefore of promoting the foaming effect of hygiene products. such as shower gels, soaps or shampoos. Within the meaning of the invention, the surfactant is chosen from anionic surfactants, cationic surfactants, amphoteric surfactants, zwitterionic surfactants or nonionic surfactants. In particular, the surfactant is chosen from surfactants having an HLB value greater than 10.

The term "HLB" or "Hydrophilic/Lipophilic Balance" relates to a number used to characterize the rather lipophilic or, on the contrary, hydrophilic character of a surfactant. If the surfactant has an HLB greater than 10 it will be mainly hydrophilic and if the HLB is less than 10 it will be rather lipophilic. Reference may be made to the document “Encyclopedia of Chemical Technology, KIRK-OTHMER”, volume 22, p. 333-432, 3rd edition, 1979, WILEY, for the definition of the properties and functions of surfactants.

The term "suspension" in the context of the present invention relates to a homogeneous dispersion of solid, semi-solid or liquid droplets, insoluble in a liquid or a gel and visible to the naked eye, that is to say having a average diameter greater than 200 µm. On the contrary, an “emulsion” relates to a colloidal system of two immiscible liquids, that is to say leading to two different phases, having a macroscopically homogeneous appearance, but microscopically heterogeneous. A first phase, the dispersed phase, is present in the form of droplets dispersed in a second homogeneous phase, the continuous phase. The average diameter of the dispersed phase droplets generally ranges from 0.1 nm to 100 µm.

The term "viscosity" relates to all the phenomena of resistance to the movement of a fluid for a flow with or without turbulence. According to the invention, the viscosities are measured at ambient temperature (20° C.) and at ambient pressure, using a Brookfield RV DV viscometer with a type 4 Spindle, at a speed of 12 revolutions/minute.

Claims (16)

Process for preparing a suspension of fatty phase beads in an aqueous surfactant gel, comprising the following steps:

1. in a first reactor, mixing, at a temperature between 30° C. and 130° C., at least one fatty phase gelling and/or thickening agent and at least one fatty substance;
2. in a second reactor, mixture of formulation water and at least one aqueous phase gelling and/or thickening agent;
3. agitation of the fluid mixture obtained in step b) until a vortex is obtained and maintenance of the vortex by constant agitation of the mixture obtained;
4. slow addition of the mixture obtained in step a) into the center of the vortex formed in step c) making it possible to obtain beads of gelled fatty phase having an average diameter greater than 300 μm;
5. addition of the mixture obtained in step d) in an aqueous solution comprising at least one surfactant and homogenization with slow stirring; And
6. adjustment of the pH of the mixture obtained in step e) to a pH of between 4.0 and 11.0 and homogenization of the mixture obtained with slow stirring.

Process according to Claim 1, in which the mixture obtained in step a) is heated to a temperature of between 70°C and 95°C, preferably between 80°C and 90°C. Process according to Claim 1 or Claim 2, in which the said at least one fatty phase gelling and/or thickening agent is chosen from organic, mineral lipophilic gelling and/or thickening agents, waxes which are solid at room temperature, butters or a mixture of these. Process according to any one of Claims 1 to 3, in which the said at least one fatty phase gelling and/or thickening agent is present in an amount ranging from 0.01% to 10% by weight relative to the total weight of the said suspension. Process according to any one of Claims 1 to 4, in which the said at least one fatty substance is chosen from alkanes, fatty alcohols, fatty acids, fatty acid esters, fatty alcohol esters, triglycerides , oils such as non-silicone mineral, vegetable, animal and synthetic oils, non-silicone waxes, silicones, pasty fatty substances or butters or a mixture thereof. Process according to any one of Claims 1 to 5, in which the said at least one fatty substance is present in an amount ranging from 0.1% to 10% by weight relative to the total weight of the said suspension. Process according to any one of Claims 1 to 6, in which the said at least one aqueous-phase gelling and/or thickening agent is chosen from synthetic anionic gelling and/or thickening agents such as carbomers, sodium polyacrylate, copolymers of acrylic or methacrylic acid, copolymers of acrylic or methacrylic acid and of a C ₁ -C ₃₀ alkyl acrylate or methacrylate, modified sulphonated acrylic acid copolymers, associative acrylic polymers or copolymers or a mixture of these. Process according to any one of Claims 1 to 7, in which the said at least one aqueous phase gelling and/or thickening agent is present in an amount ranging from 0.1% to 5.0% by weight relative to the total weight of said suspension. Process according to any one of Claims 1 to 8, in which the said at least one surfactant is chosen from cationic, anionic, non-ionic, amphoteric, zwitterionic surfactants or a mixture thereof. Process according to any one of Claims 1 to 9, in which the said at least one surfactant is present in an amount ranging from 1% to 30% by weight relative to the total weight of the said suspension. Process according to any one of Claims 1 to 10, in which, during stage f), the pH of the mixture obtained in stage e) is adjusted to a pH ranging from 4.5 to 7.0, preferably ranging from 5.0 to 5.5. Suspension of fatty phase beads in an aqueous surfactant gel, comprising:
an aqueous phase comprising:

• at least one aqueous phase gelling and/or thickening agent;
• at least one surfactant; And

a fatty phase in the form of gelled beads suspended in the aqueous phase, comprising:

• at least one fatty phase gelling and/or thickening agent; And
• at least one fatty substance,

in which the beads of fatty phase have an average diameter greater than 300 μm. Suspension according to Claim 12, obtained or capable of being obtained by the process as described in Claims 1 to 11. Suspension according to Claim 12 or Claim 13, in which the said at least one surfactant is present in an amount ranging from 1% to 30% by weight relative to the total weight of the said suspension. Suspension according to any one of Claims 12 to 14, in which the said suspension has a viscosity ranging from 500 mPa.s to 50,000 mPa.s. A suspension according to any of claims 12 to 15, wherein said suspension has a pH ranging from 4.0 to 11.0.