EMULSIONS STABILISED BY AMPHIPHILIC COMPOSITE PARTICLES

Abstract

The present invention relates to an emulsion not containing any emulsifying surfactant, in particular to an oil-in-water emulsion not containing any emulsifying surfactant, characterized in that it comprises, especially in a physiologically acceptable medium, at least composite particles comprising a core comprising at least organic or inorganic particles A; said core being covered at the surface, continuously or discontinuously, with an envelope comprising at least organic or inorganic particles B; said particles A and B having different polarities.

The present invention also relates to the use of the composite particles as defined previously as emulsion stabilizer, in particular as stabilizer for an emulsion not containing any emulsifying surfactant, and more particularly as stabilizer for an oil-in-water emulsion not containing any emulsifying surfactant.

The present invention also relates to a cosmetic process for treating a keratin material, which consists in applying to the keratin material an emulsion as defined previously.

Claims

1. An emulsion comprising, in a physiologically acceptable medium: at least composite particles comprising a core comprising at least organic or inorganic particles A; said core being covered, continuously or discontinuously, with an envelope comprising at least organic or inorganic particles B; said particles A and B having different polarities.

2. The emulsion according to claim 1, wherein the materials A and B have a difference in polarity
ΔE=E.sub.T(30)A−E.sub.T(30)B of greater than 2.

3. The emulsion according to claim 1, wherein the composite particles have a mean size ranging from 0.1 to 100 μm.

4. The emulsion according to claim 1, wherein a weight ratio of the core to the envelope of the composite particles is from 70/30 to 99.9/0.1.

5. The emulsion according to claim 1, wherein the material constituting particles A of the core of the composite particles is selected from the group consisting of: (i) crosslinked or non-crosslinked poly(meth)acrylate polymers; (ii) crosslinked organopolysiloxane elastomers; (iii) polysaccharides that are natural or of natural origin; (iv) polyamide particles; (v) particles of copolymer of styrene and of (meth)acrylic acid or a (C1-C20)alkyl ester thereof; (vi) polymethylsilsesquioxanes; (vii) inorganic particles; and (viii) mixtures thereof.

6. The emulsion according to claim 1, wherein the material constituting particles B of the envelope of the composite particles is selected from the group consisting of: (i) polymethylsilsesquioxanes; (ii) crosslinked or non-crosslinked poly(meth)acrylate polymers; (iii) fumed silicas; (iv) hydroxyapatites; (v) coated or uncoated metal oxide particles, and more particularly titanium oxide particles; (vi) alumina; and (vii) mixtures thereof.

7. The emulsion according to claim 1, wherein the composite particles are selected from the group consisting of: composite particles whose core is formed from crosslinked polymethyl methacrylate and whose envelope is formed from hydroxyapatite; composite particles whose core is formed from crosslinked polymethyl methacrylate and whose envelope is formed from fumed silica; composite particles whose core is formed from organopolysiloxane elastomer and whose envelope is formed from fumed silica, in particular particles whose core is formed from Dimethicone/Vinyl Dimethicone Crosspolymer and whose envelope is formed from fumed silica; composite particles whose core is formed from crosslinked polymethyl methacrylate and whose envelope is formed from polymethylsilsesquioxane; composite particles whose core is formed from a polysaccharide, which is in particular natural or of natural origin, and whose envelope is formed from polymethyl methacrylate; composite particles whose core is formed from polymethyl methacrylate and whose envelope is formed from fumed silica; composite particles whose core is formed from polymethylsilsesquioxane and whose envelope is formed from fumed silica; and composite particles whose core is formed from polymethyl methacrylate and whose envelope is formed from titanium oxide.

8. The emulsion according to claim 7, wherein the composite particles are composite particles whose core is formed from a polysaccharide, and whose envelope is formed from polymethyl methacrylate.

9. The emulsion according to claim 8, wherein the polysaccharide has: a wet point for oil of at least 25 ml/100 g, and a wet point for water of at least 50 mg/100 g, and a ratio of the wet point for water/wet point for oil of less than or equal to 5.

10. The emulsion according to claim 9, wherein the polysaccharide is a porous cellulose or a type II cellulose.

11. The emulsion according to claim 1, wherein the composite particles are obtained by chemical mechanofusion.

12. The emulsion according to claim 1, wherein the composite particles are present in concentrations ranging from 0.1% to 10% by weight relative to the total weight of the composition.

13. The emulsion according to claim 1, wherein the emulsion is an oil-in-water emulsion.

14. A process for preparing the oil-in-water emulsion according to claim 13, comprising: a) dispersion, at room temperature (20-25° C.), of the composite particles comprising a core comprising at least organic or inorganic particles A; said core being covered, continuously or discontinuously, with an envelope comprising at least organic or inorganic particles B; said particles A and B having different polarities, with stirring; and b) introduction of the oily phase into the aqueous phase with slow stirring; and c) optional addition of other ingredients; and d) mixing with stirring until the emulsion is formed and a macroscopically homogeneous mixture is obtained.

15. An oil-in-water emulsion comprising the composite particles according to claim 1, as emulsion stabilizer, wherein the oil-in-water emulsion does not comprise an emulsifying surfactant.

16. A cosmetic process for treating a keratin material, comprising: applying to the keratin material an emulsion according to claim 1.

Description

EXAMPLES

Example 1: O/W Emulsion

E.SUB.T.(30)A=44

E.SUB.T.(30)B=55.2

ΔE(30)=11.2

[0265]

TABLE-US-00001 Phase A Particles of methyl methacrylate crosspolymer (and) 1 g hydroxyapatite (PAC-2 ®, Sekisui Plastics) Demineralized water 66.5 g Phase B Hydrogenated polyisobutene 7 g Cyclohexasiloxane 6 g Isocetyl stearate 7 g Phase C Xanthan gum 0.5 g Demineralized water 10 g Ethanol 2 g

[0266] 1 g of PAC-2 particles was dispersed at room temperature (25° C.) in 66.6 g of demineralized water (phase A) using a paddle (Heidolph RZR2041), and phase B was then introduced slowly with continued stirring at 300 rpm for 1 hour. Phase C was then added with slow stirring. An oil-in-water emulsion that is stable after 24 hours at room temperature (25° C.), having oil drops with a mean diameter of 300 μm measured using binocular magnifying glasses, was obtained.

Example 2: O/W Emulsion

E.SUB.T.(30)A=44

E.SUB.T.(30)B=59.5

ΔE(30)=15.5

[0267]

TABLE-US-00002 Phase A Particles of methyl methacrylate crosspolymer (and) silica 1 g (Micropearl M330 ®, Matsumoto Yushi) Demineralized water 66.5 g Phase B Hydrogenated polyisobutene 7 g Cyclohexasiloxane 6 g Isocetyl stearate 7 g Phase C Xanthan gum 0.5 g Demineralized water 10 g Ethanol 2 g

[0268] According to the same protocol as example 1, an oil-in-water emulsion that is stable after 24 hours at room temperature (25° C.), having oil drops with a mean diameter of 500 μm, was obtained.

Example 3: O/W Emulsion

E.SUB.T.(30)A=38

E.SUB.T.(30)B=59.5

ΔE(30)=21.5

[0269]

TABLE-US-00003 Phase A Particles of vinyl dimethicone crosspolymer (and) silica 1 g (DC 9701 Cosmetic Powder, Dow Corning) Demineralized water 42.2 g Glycerol 7 g Propylene glycol 2 g Phase B Dimethicone (viscosity: 10 cSt 7 g Dimethicone (viscosity: 5 cSt) 4 g Phase C Biosaccharide Gum-1 2 g Demineralized water 24.3 g Polyacryldimethyltauramide 0.5 g Ethanol 10 g

[0270] According to the same protocol as example 1, an oil-in-water emulsion that is stable after 24 hours at room temperature (25° C.), having oil drops with a mean diameter of 100 μm, was obtained.

Example 4: O/W Emulsion

E.SUB.T.(30)A=44

E.SUB.T.(30)B=38

ΔE(30)=6

[0271]

TABLE-US-00004 Phase A Particles of methyl methacrylate crosspolymer (and) 1 g polymethylsilsesquioxane (Silcrusta MK03, Kobo) Demineralized water 66.5 g Phase B Dimethicone (viscosity: 10 cSt) 20 g Phase C Xanthan gum 0.5 g Demineralized water 10 g Ethanol 2 g

[0272] According to the same protocol as example 1, an oil-in-water emulsion that is stable after 24 hours at room temperature (25° C.), having oil drops with a mean diameter of 350 μm, was obtained.

Examples of Particles Obtained by Mechanofusion

[0273]

TABLE-US-00005 Core/envelope Example Core Envelope ΔE(30) weight ratio MFP-1 Cellulose (10 μm) Acrylates 7.4 97.5/2.5 (Cellulobeads D-5, Copolymer Daito) (0.35 μm) (MP-2200, Soken) MFP-2 Cellulose (10 μm) Acrylates 7.4 91.6/8.4 (Cellulobeads D-5, Copolymer Daito) (0.35 μm) (MP-2200, Soken) MFP-3 Methyl methacrylate Silica 15.5 97.7/2.3 crosspolymer (1.5 μm) (Aerosil 200, (SSX-101, Sekisui Evonik) Plastics) MFP-4 Methyl methacrylate Silica 15.5 96.1/3.9 crosspolymer (1.5 μm) (Aerosil 200, (SSX-101, Sekisui Evonik) Plastics) MFP-5 Methyl methacrylate Silica 15.5 94.4/5.6 crosspolymer (1.5 μm) (Aerosil 200, (SSX-101, Sekisui Evonik) Plastics) MFP-6 Polymethylsilsesquioxane Silica 21.5 95.3/4.7 (4.5 μm) (Aerosil 200, (Tospearl 145A, Evonik) Momentive) MFP-7 Methyl methacrylate Silica 15.5 98.9/1.1 crosspolymer (6 μm) (Aerosil 200, (MR-7GC, Soken) Evonik) MFP-8 Methyl methacrylate Titanium 17.5 94.4/5.6 crosspolymer (2.5 μm) dioxide (SSX-102, Sekisui (MT-100AQ, Plastics) Tayca)

Procedure

[0274] For each example, the components indicated in the above table were mixed, in the weight ratio indicated in the same table, in a plastic bag which was shaken for a few minutes. The mixture was then placed in a hybridizer machine sold under the trade name Nara Machinery® with a rotor spinning at 8000 rpm (linear speed of 100 m/s) for 3 minutes to obtain the composite pigments.

Example 5: O/W Emulsion

[0275]

TABLE-US-00006 Phase A Composite particles MFP-1 1 g Demineralized water 66.5 g Phase B Hydrogenated polyisobutene 7 g Cyclohexasiloxane 6 g Isocetyl stearate 7 g Phase C Xanthan gum 0.5 g Demineralized water 12 g

[0276] According to the protocol of example 1, an oil-in-water emulsion that is stable after 24 hours at room temperature (25° C.), having oil drops with a mean diameter of 300 μm, was obtained.

Example 6: O/W Emulsion

[0277]

TABLE-US-00007 Phase A Composite particles MFP-2 1 g Demineralized water 66.5 g Phase B Dimethicone (10 cSt) 20 g Phase C Xanthan gum 0.5 g Demineralized water 12 g

[0278] According to the protocol of example 1, an oil-in-water emulsion that is stable after 24 hours at room temperature (25° C.), having oil drops with a mean diameter of 500 μm, was obtained.

Example 7: O/W Emulsion

[0279]

TABLE-US-00008 Phase A Composite particles MFP-3 1 g Demineralized water 66.5 g Phase B Isopropyl myristate 20 g Phase C Xanthan gum 0.5 g Demineralized water 12 g

[0280] According to the protocol of example 1, an oil-in-water emulsion that is stable after 24 hours at room temperature (25° C.), having oil drops with a mean diameter of 260 μm, was obtained.

Example 8: O/W Emulsion

[0281]

TABLE-US-00009 Phase A Composite particles MFP-4 1 g Demineralized water 66.5 g Phase B Hydrogenated polyisobutene 20 g Phase C Xanthan gum 0.5 g Demineralized water 12 g

[0282] According to the protocol of example 1, an oil-in-water emulsion that is stable after 24 hours at room temperature (25° C.), having oil drops with a mean diameter of 250 μm, was obtained.

Example 9: O/W Emulsion

[0283]

TABLE-US-00010 Phase A Composite particles MFP-5 1 g Demineralized water 66.5 g Phase B Hydrogenated polyisobutene 20 g Phase C Xanthan gum 0.5 g Demineralized water 12 g

[0284] According to the protocol of example 1, an oil-in-water emulsion that is stable after 24 hours at room temperature (25° C.), having oil drops with a mean diameter of 250 μm, was obtained.

Examples 10 to 12: O/W Emulsions

[0285]

TABLE-US-00011 TABLE 1 Example 11 Example 12 Example 10 (outside the (outside the (invention) invention) invention) Composite particles Particles of Particles of MFP-6 fumed silica Polymethylsilsesquioxane with a core made of (Aerosil (4.5 μm) Polymethylsilsesquioxane 200 ®) (Tospearl 145A ®) (Tospearl 145A ®) and an envelope made of fumed silica (Aerosil 200 ®)

Common Support

[0286]

TABLE-US-00012 Phase A Particles according to table 1 0.5 g Demineralized water 39.5 g Phase B Hydrogenated polyisobutene 3.5 g Cyclohexasiloxane 3 g Isocetyl stearate 3.5 g

[0287] 0.5 g of particles in 39.5 g of demineralized water (phase A) was dispersed at room temperature (25° C.) by inversion in a test tube, and phase B was then introduced. Emulsification was performed by manual shaking for 30 seconds.

[0288] After 24 hours at room temperature (25° C.), it was found that only example 10 according to the invention prepared with the composite particles MFP-6 was stable, whereas emulsions 11 and 12 prepared with the core alone (Tospearl 145A) or the shell alone (Aerosil 200) were unstable (strong coalescence and two-phase system).

Example 13: O/W Emulsion

[0289]

TABLE-US-00013 Phase A Demineralized water 39.5 g Glycerol 7 g Propylene glycol 2 g Particles MFP-2 1 g Phase B Dimethicone (10 cSt) 7 g Dimethicone (5 cSt) 4 g Phase C Biosaccharide Gum-1 2 g Phase D Ammonium polyacryloyldimethyl taurate 0.5 g Demineralized water 26.3 g Phase E Phenoxyethanol 0.7 g Ethanol 10 g

[0290] 1 g of MFP-2 particles was dispersed at room temperature (25° C.) in phase A using a paddle (Heidolph RZR2041) for 5 minutes at 300 rpm, and phase B was then introduced slowly with continued stirring at 300 rpm for 1 hour. Phase C was then added with gentle stirring, followed successively by phase D and E. An 0/W emulsion that was stable after 24 hours at room temperature (25° C.), having oil drops with a mean diameter of 150 μm, was obtained.

Example 14: O/E Emulsion with Emulsifying Surfactant (Outside the Invention)

[0291]

TABLE-US-00014 Phase A Demineralized water 38.8 g Glycerol 7 g Propylene glycol 2 g Phase B Dimethicone (10 cSt) 7 g PEG-12 Dimethicone (emulsifying surfactant) 0.7 g Dimethicone (5 cSt) 4 g Phase C Biosaccharide Gum-1 2 g Phase D Ammonium polyacryloyldimethyl taurate 0.5 g Demineralized water 26.3 g Phase E Phenoxyethanol 0.7 g Ethanol 10 g Phase F Particles MFP-2 1 g

[0292] According to the protocol of example 16, an O/W emulsion that is stable after 24 hours at room temperature (25° C.), having oil drops with a mean diameter of 50 μm, was obtained.

Measurement of the Mattness/Gloss

Protocol for Measuring the Mattness of a Composition

[0293] The gloss of a deposit resulting from the application of a composition may be commonly measured according to various methods, such as the method using a Byk Micro TRI gloss 60° glossmeter.

Principle of the Measurement Using this Glossmeter

[0294] The machine illuminates the sample to be analyzed at a certain incidence and measures the intensity of the specular reflection.

[0295] The intensity of the reflected light depends on the material and on the angle of illumination. For non-ferrous materials (paint, plastic), the intensity of reflected light increases with the angle of illumination. The rest of the incident light penetrates the material and, depending on the shade of the color, is either partly absorbed or scattered.

[0296] The reflectometer measurement results are not based on the amount of incident light but on a polished black glass standard of defined refractive index.

[0297] The measurement is normalized relative to an internal standard and brought to a value out of 100: for this calibration standard, the measurement value is set at 100 gloss units (calibration).

[0298] The closer the measured value is to 100, the more glossy the sample. The measurement unit is the Gloss Unit (GU).

[0299] The angle of illumination used has a strong influence on the reflectometer value. In order to be able to readily differentiate very glossy and matt surfaces, the standardization has defined 3 geometries or 3 measurement domains.

Test Protocol

[0300] a—Spread a coat with a wet thickness of 30 μm of the composition whose mean gloss value it is desired to evaluate onto an Erichsen Type 24/5® brand contrast card, using an automatic spreader. The coat covers the white background and the black background of the card.

[0301] b—Leave to dry for 24 hours at 37° C.

[0302] c—Measure the gloss at an angle of 60° on the matt white absorbent background (3 measurements) using a Byk Gardner brand glossmeter of reference microTri-Gloss.

TABLE-US-00015 Composition Gloss at 60° Example 13 GU = 10.5 ± 0.9 Example 14 GU = 20.8 ± 0.8

[0303] It was found that the composite particles had mattness properties that were maximized when they were used to stabilize the oil/water interface.

Example 15: O/W Emulsion

[0304]

TABLE-US-00016 Phase A Composite particles MFP-7 1 g Demineralized water 66.5 g Phase B Glycine Soya Oil 20 g Phase C Xanthan gum 0.5 g Demineralized water 12 g

[0305] According to the same protocol as example 1, an O/W emulsion that is stable after 24 hours at room temperature (25° C.), having oil drops with a mean diameter of 50 μm, was obtained.

Example 16: O/W Emulsion

[0306]

TABLE-US-00017 Phase A Composite particles MFP-8 1 g Demineralized water 66.5 g Phase B Isopropyl myristate 20 g Phase C Xanthan gum 0.5 g Demineralized water 12 g

[0307] According to the same protocol as example 1, an O/W emulsion that is stable after 24 hours at room temperature (25° C.), having oil drops with a mean diameter of 500 μm, was obtained.