Patent ID: 7540984

Claim:
A process for preparing a membrane which comprises process (1) or process (2), wherein the process of (1) comprises A1) mixing of one or more aromatic tetraamino compounds with one or more aromatic carboxylic acids or esters thereof which contain at least two acid groups per carboxylic acid monomer, or mixing of one or more aromatic and/or heteroaromatic diaminocarboxylic acids, in polyphosphoric acid to form a solution and/or dispersion, B1) application of a layer to a support using the mixture from step A1), C1) heating of the flat structure/layer obtained as described in step B1) to temperatures of up to 350° C. under inert gas to form the polyazole polymer, D1) treating the membrane formed in step C1) by hydrolysis until it is self-supporting, or wherein the process of (2) comprises A2) mixing of one or more aromatic tetraamino compounds with one or more aromatic carboxylic acids or esters thereof which contain at least two acid groups per carboxylic acid monomer, or mixing of one or more aromatic and/or heteroaromatic diaminocarboxylic acids, in polyphosphoric acid to form a solution and/or dispersion, B2) heating of the mixture in step A2) to temperatures of up to 350° C. under inert gas to form the polyazole polymer, C2) application of a layer to a support using the polymer from step B2), D2) treating the membrane formed in step C2) by hydrolysis until it is self-supporting.