PRODUCTION OF POLYVINYL ALCOHOL RESIN MOLDING

摘要

PURPOSE:To produce a molding which difficultly colors, difficultly forms fish eyes and has a very excellent quality by improving the heat stability of an unplasticized polyvinyl alcohol resin of a high degree of saponification in melt- molding the resin. CONSTITUTION:The heat stability of a polyvinyl alcohol resin is improved by adjusting the viscosity of an aqueous solution of the resin (in a concentration of 4wt.% at 20 deg.C) to 7cP or below and the content of methanol solubles to 5wt.% or below.