METHOD OF MANUFACTURING POLYMER ELECTROLYTE MEMBRANE

摘要

PROBLEM TO BE SOLVED: To provide a method of manufacturing a polymer electrolyte membrane in which unevenness of thickness, wrinkles, and irregularities are hardly caused and which is improved in morphology stability of membrane and stability of membrane characteristics.

SOLUTION: The method of forming the polymer electrolyte membrane includes: a spread step (A1) in which ionic group-contained polymer electrolyte solution is flowed and spread on a support to form a spread membrane; a drying step (A2) of evaporating solvent from the spread membrane; and a desolvation step (A3) of extracting the solvent by a liquid in which the dried membrane is mixed in a solvent of the ionic group-contained polymer electrolyte. In the method, the step (A2) and the step (A3) are carried out without separating the membrane from the support. In the drying step (A2), the polymer electrolyte membrane is dried so that it becomes a self-supporting membrane of solvent content 15-30 mass% in the range of the following formula (I) as to the relation of the coating thickness factor T of the polymer electrolyte solution and the drying speed R1 (g/m2×min.). 2≤R1×T≤56 (I), provided that R1expresses a drying speed (g/m2xmin.), T expresses a coating thickness (μm)/300(μm) of the polymer electrolyte solution.

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