Patent ID: 9074031
Filing Date: 2015-07-07
Classification: C08F,C08J

Abstract:
1. A method of producing a polyvinyl alcohol resin, comprising obtaining a polyvinyl alcohol by saponification of a polyvinyl ester, and then washing the polyvinyl alcohol in a slurry state with a washing liquid to remove sodium acetate therefrom, wherein the washing liquid contains methyl acetate, methanol and water, and the amount of the washing liquid components in the slurry is methyl acetate: 1 to 40 parts by mass, methanol: 50 to 98.9 parts by mass and water: 0.1 to 10 parts by mass, and wherein the amount of the polyvinyl alcohol in the slurry is within a range of 1 to 30 mass %, and wherein after an initial washing with the washing liquid, the washing liquid is separated from the polyvinyl alcohol by filtration, and the filtrate is used in a subsequent washing of the polyvinyl alcohol in a slurry state, and the washing and the filtration steps are repeated multiple times.