Cosmetic oil-in-water emulsion
A cosmetic or dermatological compositions of oil-in-water emulsion type, including, in a physiologically acceptable medium, at least gemini surfactant of formula (I): in which R 1 and R 3 denote, independently of one another, an alkyl radical containing from 1 to 25 carbon atoms; R 2 denotes a spacer consisting of a linear or branched alkylene chain containing from 1 to 12 carbon atoms; X and Y denote, independently of one another, a group —(C 2 H 4 O) a —(C 3 H 6 O) b Z; n ranges from 1 to 10, in combination with an effective amount of at least one semi-crystalline polymer which is solid at ambient temperature and which has a melting point below 70° C., said polymer having a number-average molecular mass greater than or equal to 2000, said emulsion having a proportion of fatty phase of greater than 10% by weight relative to the total weight of the composition and including more than 40% by weight of non-volatile oil(s) relative to the weight of the fatty phase.
1. A cosmetic or dermatological composition of oil-in-water type comprising, in a physiologically acceptable medium, at least one gemini surfactant of formula (I):
in which:
R 1 and R 3 denote, independently of one another, an alkyl radical containing from 1 to 25 carbon atoms;
R 2 denotes a spacer consisting of a linear or branched alkylene chain containing from 1 to 12 carbon atoms;
X and Y denote, independently of one another, a —(C 2 H 4 O) a —(C 3 H 6 O) b Z group where:
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, M′ represent H or an alkali metal ion, an alkaline earth metal ion, an ammonium ion 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,
in combination with an effective amount of at least one semi-crystalline homopolymer which is solid at ambient temperature and which has a melting point of below 70° C., comprising:
a) a polymeric backbone, and
b) at least one crystallizable organic side chain,
said homopolymer having a number-average molecular mass greater than or equal to 2000, and
said semi-crystalline homopolymer resulting from the polymerization of only monomers comprising a crystallizable chain, selected from the group consisting of C14-C24 alkyl (meth)acrylates,
said composition having a proportion of fatty phase greater than 10% by weight relative to a total weight of said composition and comprising more than 40% by weight of non-volatile oil(s) relative to a total weight of the fatty phase,
wherein the gemini surfactant is present at a content ranging from 0.01% to 5% by weight, relative to a total weight of the composition.
2. The composition according to claim 1 , wherein each of the groups R 1 —CO— and R 3 —CO— denotes a coconut fatty acid residue.
3. The composition according to claim 1 , wherein, for the gemini surfactant of formula (I), for each of the radicals X and Y, the sum of a and b has a mean value ranging from 10 to 20.
4. The composition according to claim 1 , wherein, for the gemini surfactant of formula (I), Y is the group —SO 3 M where M is an alkali metal ion.
5. The composition according to claim 1 , wherein, for the gemini surfactant of formula (I), n is equal to 1.
6. The composition according to claim 1 , wherein the surfactant of formula (I) has the following structure:
7. The composition according to claim 1 , wherein the gemini surfactant is mixed with (a) a glyceryl ester of a C 6 -C 22 fatty acid, (b) a glycerol diester of a C 6 -C 22 fatty acid and of citric acid, and (c) a C 10 -C 30 fatty alcohol.
8. The composition according to claim 1 , wherein the gemini surfactant is present at a content ranging from 0.2% to 1.5% by weight relative to a total weight of the composition.
9. The composition according to claim 1 , wherein the polymer has a number-average molecular mass ranging from 3000 to 500,000.
10. The composition according to claim 1 , wherein the polymer is soluble in the fatty phase to at least 1% by weight at a temperature above its melting point.
11. The composition according to claim 1 , wherein the polymer has a melting point Tm such that 30° C.≦Tm<50° C.
12. The composition according to claim 1 , containing at least one organic UV screen.
13. A cosmetic method for making up and/or for the non therapeutic care of keratin materials, comprising at least a step of applying to keratin materials a composition according to claim 1 .
14. The composition according to claim 4 , wherein M is a sodium ion.
15. The composition according to claim 1 , wherein the gemini surfactant is present at a content ranging from 0.1% to 3% by weight, relative to a total weight of the composition.