National Starch and Chemical Investment Holding Corporation

Tetsuo Sakurai

Seiji Asaoka

Tomohiro Hashimoto

Takeshi Baba

The invention presents a method for manufacturing an amphoteric urethane resin, improving at least one of the performance of cosmetics including this amphoteric urethane resin and the storage stability of the urethane resin. The method for manufacturing an amphoteric urethane resin uses (A) a polyol; (B) a polyisocyanate; (C) a polysiloxane compound (except any having at least one selected from a hydroxyl group, a primary amino group and a secondary amino group at one or both ends of the siloxane chain); (D) a compound having carboxyl groups and at least one selected from a hydroxyl group, a primary amino group and a secondary amino group; (E) a compound having tertiary amino groups and at least one selected from a hydroxyl group, a primary amino group and a secondary amino group; and the method includes a step of making a prepolymer including isocyanate groups by reacting the compounds (A), (B) and (D) with excessive isocyanate groups; and a step of reacting the prepolymer including the isocyanate groups with the compound (E); wherein the compound (C) is present in at least one of the first step and the second step.

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Toyonaka, Japan

Tetsuo Sakurai