Cosmetic emulsion containing a gemini surfactant and a lipophilic polymer
Cosmetic emulsion containing a gemini surfactant and a lipophilic polymer The invention relates to a composition in the form of an emulsion, in particular in the form of an oil-in-water emulsion, comprising a gemini surfactant having a specific chemical structure with at least two fatty amide groups and at least one lipophilic polymer comprising at least hydroxyethyl acrylate units and acrylate units bearing a lipophilic group, wherein the weight ratio of the sum of all the hydroxyethyl acrylate units to the sum of all the acrylate units bearing a lipophilic group ranges from 1:30 to 1:1 and wherein the lipophilic polymer has a number-average molecular weight Mn ranging from 2000 to 9000 g/mol. The composition in accordance with the invention makes it possible to obtain a cosmetic emulsion having an increased sun protection factor, while at the same time having good cosmetic properties, such as a non-greasy and non-tacky feel, while at the same time being stable, in particular from the physicochemical viewpoint.
1. A composition in the form of an emulsion comprising 0.1% to 45% by weight based upon the weight of the composition of at least one UV-screening agent, 0.01% to 5% by weight based upon the weight of the composition of at least one gemini surfactant having the Chemical Formula (II) shown below, or stereoisomers thereof:
in which:
R 1 and R 3 denote, independently of each other, an alkyl radical containing from 1 to 25 carbon atoms;
R 2 denotes a spacer constituted of a linear or branched alkylene chain containing from 1 to 12 carbon atoms;
X and Y denote, independently of each other, —(C 2 H 4 O)a —(C 3 H 6 O) b Z, in which
Z denotes a hydrogen atom or a radical —CH 2 —COOM, —SO 3 M, —P(O)(OM) 2 , —C 2 H 4 —SO 3 M, —C 3 H 6 —SO 3 M or —CH 2 (CHOH) 4 CH 2 OH, where M represents H or an alkali metal or alkaline-earth metal or ammonium or alkanolammonium ion,
a ranges from 0 to 15,
b ranges from 0 to 10, and
the sum of a +b ranges from 1 to 25; and
n ranges from 1 to 10;
and
0.1% to 10% by weight based upon the weight of the composition of at least one lipophilic polymer chosen from copolymers of behenyl acrylate and 2-hydroxyethyl acrylate having a number-average molecular weight Mn ranging from 5000 to 9000 g/mol and a weight ratio of the 2-hydroxyethyl acrylate to behenyl acrylate from 1:15 to 1:1; and wherein the sum of the total units of the 2-hydroxyethyl acrylate and behenyl acrylate is 100% by weight of the total weight of the copolymer.
2. The composition according to claim 1 , in which, for the at least one gemini surfactant of formula (II), each of the R 1 —CO— and R 3 —CO— groups is a residue from a fatty acid that comprises from 8 to 20 carbon atoms.
3. The composition according to claim 1 , in which, for the at least one gemini surfactant of formula (II), each of the R 1 —CO— and R 3 —CO— groups denotes a coconut fatty acid residue.
4. The composition according to claim 1 , in which, for the at least one gemini surfactant of formula (II), for each of the X and Y radicals, the sum of a and b has a mean value ranging from 10 to 20.
5. The composition according to claim 1 , in which, for the at least one gemini surfactant of formula (II), Z is the —SO 3 M group, where M is an alkali metal ion.
6. The composition according to claim 1 , in which, for the at least one gemini surfactant of formula (II), n is equal to 1.
7. The composition according to claim 1 , in which the at least one gemini surfactant of formula (II) has the following structure:
8. The composition according to claim 1 , in which the at least one gemini surfactant of formula (II) is mixed with (a) a glyceryl ester of a C 6 -C 22 fatty acid, (b) a diester of a C 6 -C 22 fatty acid and of citric acid and of glycerol, and (c) a C 10 -C 30 fatty alcohol.
9. The composition according to claim 1 , in which the at least one lipophilic polymer has a melting point ranging from 60° C. to 69° C.
10. The composition according to claim 9 in which the at least one gemini surfactant of formula (II) has the following structure:
11. The composition according to claim 1 , in which the at least one lipophilic polymer is present in an amount ranging from 0.1% to 3% by weight relative to the total weight of the composition.
12. A process for caring for and/or removing makeup from and/or cleansing keratin materials which comprises applying to the keratin materials the composition according to claim 1 .
13. A cosmetic process for treating a keratin material, in which the composition as defined in claim 1 is applied to the keratin material.
14. The composition according to claim 1 , which is an oil-in-water emulsion.