Verfahren zur Herstellung einer Kationenaustauschermembran

摘要

A process is disclosed for producing a cation-exchanging membrane. An organic polymer with sulphonic acid groups and finely divided electroconductive particles of a catalyst material is introduced into a liquid phase and the resulting suspension is used to coat at least one side of a foil made of a cation exchanger material. The process is characterised in that the organic polymer with sulphonic acid groups is soluble in an aprotic polar solvent and contains units of formulas (Ar<1>X) and (Ar<2>Y) at least partially substituted by sulphonic acid groups. Ar<1> and Ar<2> stand for identical or different bivalent arylene radicals, X stands for oxygen or sulphur and Y stands for a carbonyl, sulphoxide or sulphonyl radical. This material is dissolved in a solvent, a finely divided electroconductive catalyst material is suspended in the solution and a foil which contains a polymer cation exchanger with sulphonic acid groups is coated with this suspension. The still solvent-containing coating is treated with a liquid miscible with the solvent but in which the dissolved cation exchanger material is not soluble, so that pores are formed in the resulting film that coats the membrane.