CATION-EXCHANGE MEMBRANE FOR ELECTROLYZING ALKALI METAL HALIDE

摘要

A cation-exchange membrane for carrying out an electrolyzing method in which an aqueous solution of alkali metal halide is supplied to an anode chamber and water to a cathode chamber to obtain halogen from the anode chamber and hydrogen and an alkali metal hydroxide from the cathode chamber. The cation-exchange membrane is made of a perfluorocarbon polymer and comprises layers including one layer which is used in electrolyzing an aqueous solution of an alkali metal halide for the manufacture of an alkali hydroxide and halogen and has a carboxylic acid group within an extent of depth 5 to 30% of the thickness of the membrane; another which has a weakly acidic group within an extent of depth 5 to 30% of the thickness of the membrane and 10% to less than 100% in ration to the total exchange group of the layer; and a middle layer which has a sulfonic acid group.