Cosmetic emulsions with long-term stability
View Patent ↗Low-viscosity, finely divided oil-in-water emulsions with long-term stability, comprising an emulsifier combination of noncarbohydrate polyol partial esters of linear or branched, saturated or unsaturated fatty acids having 6 to 22 carbon atoms (emulsifier component A) and emulsifiers based on carbohydrate (emulsifier component B), one or more oils, and preservative are provided. Additionally, the present invention provides for the preparation of the emulsions from concentrates, the corresponding concentrates, and the use of the emulsions according to the invention for producing cosmetic, dermatological or pharmaceutical preparations, in particular for producing impregnation emulsions for wet wipes.
1. An oil-in-water emulsion comprising a non-ethoxylated emulsifier combination including noncarbohydrate polyol partial esters of linear or branched fatty acids having 6 to 22 carbon atoms (emulsifier component A) and emulsifiers based on carbohydrate (emulsifier component B), one or more oils, and at least 10% by weight of preservative, based on the total amount of emulsifier components A and B.
2. The oil-in-water emulsion as claimed in claim 1 , which comprises 20 to 75% by weight of preservative, based on the total amount of emulsifier components A and B.
3. The oil-in-water emulsion as claimed in claim 1 , which additionally comprises coemulsifiers and customary auxiliaries and additives.
4. The oil-in-water emulsion as claimed in claim 1 , wherein emulsifier component A comprises exclusively or partly polyglycerol partial esters which are obtainable by reacting polyglycerols with linear or branched fatty acids having 6 to 22 carbon atoms.
5. The oil-in-water emulsion as claimed in claim 4 , wherein the polyglycerol mixture has an average degree of condensation of from 2 to 10.
6. The oil-in-water emulsion as claimed in claim 4 , wherein the degree of esterification of the polyglycerol mixture is between 5 and 70%, based on the original hydroxyl groups of the polyol.
7. The oil-in-water emulsion as claimed in claim 1 , wherein the emulsifier component A is formed partly or completely by sorbitan mono- and/or diesters of unsaturated and saturated fatty acids having 6 to 22 carbon atoms.
8. The oil-in-water emulsion as claimed in claim 7 , wherein emulsifier component A comprises, besides one or more polyglycerol partial esters, up to 50% by weight of sorbitan esters, based on the total amount of emulsifier component A.
9. The oil-in-water emulsion as claimed in claim 1 , wherein the emulsifier component B is selected from one or more of the following groups
i) esters of mono- and/or polysaccharides and one or more linear or branched fatty acids having 6 to 22 carbon atoms,
ii) glycosides of mono- or polysaccharides and linear or branched fatty alcohols having 6 to 22 carbon atoms,
iii) glycosides which have additionally been etherified with linear or branched fatty alcohols having 1 to 22 carbon atoms, and
iv) glycoside esters of mono- or polysaccharides and linear or branched fatty alcohols having 1 to 22 carbon atoms and one or more linear or branched fatty acids having 1 to 22 carbon atoms.
10. The oil-in-water emulsion as claimed in claim 1 , wherein the emulsifier component B is an alkyl polyglycoside having, on average, 1 to 5 sugar units.
11. The oil-in-water emulsion as claimed in claim 1 , wherein the emulsifier components A and B are used in a weight ratio of from 9:1 to 1:9.
12. The oil-in-water emulsion as claimed in claim 1 , wherein the total amount of the emulsifier components A+B used, based on the amount of oil to be emulsified, is in a range from 15 to 70% by weight.
13. The oil-in-water emulsion as claimed in claim 1 , wherein the total amount of oil phase (emulsifier+oil) is in the range from 1 to 25% by weight.
14. The oil-in-water emulsion as claimed in claim 1 , wherein the preservatives comprise mixtures of alkyl paraben esters with phenoxyethanol.
15. A method of preparing finely divided, low-viscosity oil-in-water emulsions comprising providing an emulsion concentrate at a temperature of about 40° C. or above, and diluting said emulsion concentrate, said emulsion concentrate comprising an emulsifier combination of noncarbohydrate polyol partial esters of linear or branched fatty acids having 6 to 22 carbon atoms (emulsifier component A) and emulsifiers based on carbohydrate (emulsifier component B), one or more oils, and at least 10% by weight of preservative, based on the total amount of emulsifier components A and B.
16. The method as claimed in claim 15 , wherein said emulsion concentrate has a 30 to 90% strength transparency.
17. The method as claimed in claim 15 , wherein the emulsion concentrate is stirred into an initially charged water phase of from 20° C. to 50° C.
18. An essentially PEG-free, transparent concentrate in the range from 50° C. to 65° C., comprising 30 to 90% by weight of a PEG-free emulsifier combination of noncarbohydrate polyol partial esters of linear or branched fatty acids having 6 to 22 carbon atoms (emulsifier component A) and emulsifiers based on carbohydrate (emulsifier component B), one or more oils, and preservative.
19. The concentrate as claimed in claim 18 , which comprises 15 to 70% by weight of the emulsifier combination.
20. A preparation comprising at least an emulsion concentrate comprising an emulsifier combination of noncarbohydrate polyol partial esters of linear or branched fatty acids having 6 to 22 carbon atoms (emulsifier component A) and emulsifiers based on carbohydrate (emulsifier component B), one or more oils, and at least 10% by weight of preservative, based on the total amount of emulsifier components A and B.
21. The preparation as claimed in claim 20 , which is substantially free of polyethylene glycol.