COPOLYURETHANE RESIN HAVING POLYLACTIC ACID SEGMENT, AND AQUEOUS EMULSION AND COATING FLUID COMPOSITION, CONTAINING SAME

摘要

Provided are a self-emulsifiable polylactic acid resin which can form a stable aqueous dispersion even without adding an emulsifying agent; and an aqueous dispersion and a coating fluid composition which contain the polylactic acid resin. Specifically provided are a copolyurethane resin which has in the molecule both a polylactic acid segment and a segment bearing sulfonic acid salt groups; an aqueous emulsion wherein the copolyurethane resin is dispersed in a liquid; and a coating fluid composition containing the aqueous emulsion.  It is preferable that the segment bearing sulfonic acid salt groups consists of a copolyester.  It is also preferable that the sulfonic acid salt groups are composed of one or more kinds of groups selected from among metal sulfonate groups, quaternary ammonium sulfonate groups, and quaternary sulfonium sulfonate groups.