METHOD OF PRODUCING POLYVINYL ALCOHOL RESIN, AND POLYVINYL ALCOHOL RESIN OBTAINED THEREBY

摘要

Provided is a method of producing a polyvinyl alcohol resin, and the polyvinyl alcohol resin obtained thereby, which has increased transparency in aqueous solution, good outer appearance in film and aqueous gel, improved ink receptivity and chromogenicity when used as a heat-sensitive recording material or ink-jet recording material, and improved water resistance. In this method of producing a polyvinyl alcohol resin is a copolymerization method, in a step for copolymerization of an aliphatic vinyl ester (A) and a diacetone acrylamide (B) in an alcohol medium in the presence of a polymerization catalyst, at least part of the diacetone acrylamide (B) is added subsequently; this method is characterized in that the ratio (a)/(b) of the polymerization yield rate (a) at the completion of polymerization and the polymerization yield rate (b) at the end of subsequent addition of the diacetone acrylamide (B) is in the range 1.01-1.10, and in that the obtained copolymer is saponified.