PROCESS FOR PRODUCING ETHYLENE-VINYL ALCOHOL COPOLYMERS

摘要

Process for producing ethylene-vinyl ester copolymers using a polymerization solvent of a dialkyl sulfoxide (process X); process for producing ethylene-vinyl alcohol copolymer by liquid phase saponification using a solvent of a dialkyl sulfoxide (process Y); and process for producing shaped articles which comprises contacting the ethylene-vinyl alcohol copolymer obtained by the process Y, or that obtained by saponifying the ethylene-vinyl ester copolymer obtained by process X, to a non-solvent for ethylene-vinyl alcohol copolymer. Ethylene-vinyl ester copolymers having a wide range of ethylene content and higher degree of polymerization than that with solution polymerization using methanol. The rate of saponification is higher than that with single solvent system of lower alcohol. Production cost is low, because production process of polymer is directly connected to that of shaped articles utilizing the polymer.