Patent ID: 11931448
Assignee: SHISEIDO COMPANY, LTD.
Field: Pharmaceuticals (Chemistry)
Classification: CPC A | IPC A

Claim 0:
1. A water-in-oil emulsion composition comprising:
(a) 0.5 to 3% by mass of a polyoxyalkylene/alkyl co-modified silicone;
(b) 0.01% by mass or greater of a core-corona particle;
(c) an oil-phase component; and
(d) an aqueous-phase component,
wherein the core-corona particle (b) is obtained by radically polymerizing a polyethylene oxide macromonomer represented by the following formula (1), and a hydrophobic monomer selected from a group consisting of an acrylate/methacrylate derivative monomer represented by the following formula (2) and an acrylamide/methacrylamide derivative monomer represented by the following formula (3), under presence or absence of a crosslinking polymer represented by the following formula (4) and under the following conditions (A) to (E);
(A) a mole ratio expressed by a feed mole amount of the polyethylene oxide macromonomer/a feed mole amount of the hydrophobic monomer is 1:10 to 1:250;
(B) a feed amount of the crosslinking monomer relative to a feed amount of the hydrophobic monomer is 0.1 to 1.5% by mass;
(C) the acrylate/methacrylate derivative monomer represented by the following formula (2) has a monomer composition of which one type or two or more types of a methacrylic acid derivative having a 1-8C alkyl group is mixed; and

the acrylamide/methacrylamide derivative monomer represented by the following formula (3) is an acrylamide derivative or a methacrylamide derivative having a substituent having a 1-18C alkyl group;
(D) a polymerization solvent is a water-alcohol mixed solvent, and the alcohol is one type or two or more types selected from a group consisting of ethanol, dipropylene glycol, 1,3-butylene glycol and isoprene glycol; and
(E) solvent composition of the water-alcohol mixed solvent is water:alcohol=90 to 10:10 to 90 in a mass ratio at 20° C., (1) R1 is a 1-3C alkyl group, and n is a number of 8 to 200, X is H or CH3, (2) R2 is a 1-3C alkyl group, and R3 is a 1-12C alkyl group, (3) R4 is H or a 1-3C alkyl group, and R5 and R6 are H or substituents having a 1-18C alkyl group, (4) R7 and R8 are independently a 1-3C alkyl group, and m is a number of 0 to 2.