Cation exchange membrane for electrolysis and process for the production of high-purity potassium hydroxide

摘要

A cation exchange membrane for electrolysis, which comprises at least 2 layers of fluorine-containing polymer films having sulfonic acid groups, wherein a first layer facing a cathode is made of a three component polymer of the following monomers (A), (B) and (C) and has a thickness of from 50 to 150 mu m, and a second layer has a thickness of from 50 to 300 mu m: (A) CF2=CF(OCF2CFCF3)mO(CF2)nSO3M wherein m = 0 or 1, n = 1 to 5, and M is hydrogen or an alkali metal, (B) CF2=CF2, CHEM wherein m = 0 or 1, and Rf is a C1-10 perfluoroalkyl group.