Electrolyte polymer for fuel cells, process for its production, electrolyte membrane and membrane/electrode assembly

摘要

The present invention relates to a process for producing an electrolyte polymer for fuel cells which comprises a step of contacting fluorine gas with a perfluorocarbon polymer (which may contain etheric oxygen atoms) having precursor groups for ion exchange groups, and further steps of hydrolysis, treatment for conversion to an acid form and washing with water, to convert the precursor groups to ion exchange groups, characterized in that , after any one of the steps of hydrolysis, treatment for conversion to an acid form and washing with water, a step of contacting the above perfluorocarbon polymer with an aqueous hydrogen peroxide solution is carried out, and in a step of contacting the above perfluorocarbon polymer with water after the step of contacting with the aqueous hydrogen peroxide solution, water having TOC (total organic carbon component) of at most 500 ppb is used as the water.