Patent ID: 11964043
Assignee: SHISEIDO COMPANY, LTD.
Field: Pharmaceuticals (Chemistry)
Classification: CPC A  C | IPC A  C

Claim 0:
1. A method for the preparation of an oil-in-water cosmetic, comprising the steps of dispersing uncrosslinked core-corona microparticles into the aqueous phase, adding the oil phase, and applying shearing force for a time sufficient to emulsify the resulting mixture, wherein:
the core-corona microparticles are obtained by radical co-polymerization of a polyethylene oxide macromonomer represented by chemical formula (1), wherein R1 is selected from the group consisting of H and alkyl groups having 1 to 3 carbon atoms, n is a number of 8 to 200, and X is selected from a group consisting of H and CH3;

with at least one hydrophobic monomer selected from the group consisting of an acrylate monomer represented by chemical formula (2), wherein R2 is selected from the group consisting of H and alkyl groups having 1 to 3 carbon atoms, and R3 is a substituent that has an alkyl group having 1 to 12 carbon atoms, and

with an acrylamide monomer represented by chemical formula, wherein R4 is selected from the group consisting of H and alkyl groups having 1 to 3 carbon atoms, and R5 and R6 are independently selected from the group consisting of H and substituents that have an alkyl group having 1 to 18 carbon atoms;

and wherein
(A) the molar ratio of the polyethylene oxide macromonomer to the total amount of acrylate monomer and acrylamide monomer ranges from 1:10 to 1:250;
(B) the radical co-polymerization is carried out in a mixture of water and one or more alcohols selected from the group consisting of ethanol, dipropylene glycol, 1,3-butylene glycol and isoprene glycol;
(C) the mass ratio of alcohols to water ranges from 9/1 to/9;
and
(D) the total percentage by weight of the monomers represented by chemical formulas (1), (2) and (3) above is 100% of the total final copolymer.