Emulsifier for highly liquid W/O emulsion based on partly crosslinked polyglycerol esters of polyhydroxystearic acid
View Patent ↗The present invention relates to polyglycerol partial esters of polyhydroxystearic acid and polyfunctional carboxylic acids which are obtainable by esterification of a polyglycerol mixture with polyhydroxystearic acid where N=1 to 10, preferably 2 to 8, in particular 3 to 5 units and dimer fatty acids which have been obtained by catalytic dimerization of unsaturated fatty acids having 12 to 22 C atoms and have an average functionality of 2 to 3, and/or with aliphatic, linear or branched dicarboxylic acids having a chain length of 2 to 16 C atoms and additionally saturated or unsaturated, linear or branched fatty acids having 6 to 22 C atoms, preferably 12 to 18 C atoms, the degree of esterification of the polyglycerol mixture being between 20 and 75%, preferably 40 to 70%.
1. A W/O emulsifier for cosmetic or pharmaceutical formulations comprising at least a polyglycerol partial ester of polyhydroxystearic acid and polyfunctional carboxylic acids, obtainable by esterification of a
a) polyglycerol mixture, with
b) polyhydroxystearic acid and
c) di-, tricarboxylic acids or mixtures thereof,
wherein said emulsifier provides a W/O emulsion having a viscosity of 13 Pas or less that is stable when cooled to −15° C. or below.
2. A W/O emulsifier as claimed in claim 1 , wherein the polyglycerol mixture has an average degree of condensation of 1 to 10.
3. A W/O emulsifier as claimed in claim 1 , wherein the polyhydroxystearic acid has an average degree of condensation of 1 to 10.
4. A W/O emulsifier as claimed in claim 1 , wherein component c) comprises aliphatic, linear or branched dicarboxylic acids that contain 2 to 16 C atoms.
5. A W/O emulsifier as claimed in claim 1 , wherein the polyglycerol partial ester further comprising at least one dimer fatty acid.
6. A W/O emulsifier as claimed in claim 5 , wherein the at least one dimer fatty acid has an average functionality of 2 to 3.
7. A W/O emulsifier as claimed in claim 1 , wherein the polyglycerol partial ester further comprising at least one fatty acid having 6 to 22 carbon atoms.
8. A W/O emulsifier as claimed in claim 1 , wherein the polyglycerol partial ester further comprising at least one dimer fatty acid and at least one fatty acid having 6 to 22 carbon atoms.
9. A W/O emulsifier as claimed in claim 7 , wherein the at least one fatty acid comprises a saturated or unsaturated, linear or branched monobasic acid having 6 to 22 C atoms.
10. A W/O emulsifier as claimed in claim 1 , wherein the degree of esterification of the polyglycerol mixture is between 20 and 75% of the OH groups.
11. A W/O emulsifier for cosmetic or pharmaceutical formulations comprising at least a polyglycerol partial ester which is obtainable by esterification of
a) 1.0 mol of OH groups of a polyglycerol mixture with
b) 0.01 to 0.9 mol of COOH groups of a polyhydroxystearic acid and
c) 0.01 to 0.9 mol of COOH groups of di-, tricarboxylic acids or mixtures thereof,
d) 0 to 0.9 mol of COOH groups of dimer fatty acids, and
e) 0.1 to 0.9 mol of COOH groups of fatty acids having 6 to 22 C atoms, with the proviso that the sum of the COOH groups approximately corresponds to 20 to 75% of the OH groups of the polyglycerol mixture,
wherein said emulsifier provides a W/O emulsion having a viscosity of 13 Pas or less that is stable when stored 12 hr at −15° C. or −25° C.
12. A process for the preparation of a polyglycerol partial ester of the W/O emulsifier as claimed in claim 1 comprises, in a first stage esterification of polyglycerol with a fatty acid and di- and/or tricarboxylic acid and/or a dimer acid up to a degree of esterification of 10 to 70%, and in
a second stage esterification of the product with polyhydroxystearic acid to a total degree of esterification of 20 to 75%, or in
a first stage esterification of polyglycerol with a fatty acid and polyhydroxystearic acid up to a degree of esterification of 10 to 70%, and in
a second stage esterification of the product with di- and/or tricarboxylic acid and/or a dimer acid to a total degree of esterification of 20 to 75%.