Patent ID: 7883818

Claim:
A process for producing proton-conducting polymer membranes, which comprises the steps A) preparation of a mixture comprising polyphosphoric acid, at least one polyazole and/or one or more compounds suitable for forming polyazoles under the action of heat in step B), with these compounds comprising one or more aromatic and/or heteroaromatic tetramino compounds and one or more aromatic and/or heteroaromatic carboxylic acids or derivatives thereof which contain at least two acid groups per carboxylic acid monomer, and/or one or more aromatic and/or heteroaromatic diaminocarboxylic acids, B) heating of the mixture obtainable according to step A) to temperatures up to 400° C. under inert gas, C) application of a layer to a support using the mixture from step A) and/or B), D) treatment of the membrane formed in step C), characterized in that the treatment of the membrane is carried out using a hydrolysis liquid comprising oxo acids of phosphorus and/or oxo acids of sulfur.