| 摘要 |
PROBLEM TO BE SOLVED: To provide a production method of an electrolytic film which allows the efficient industrial production of an electrolytic film having excellent durability, high ion conductivity and low fuel permeability.SOLUTION: The production method of a polymer electrolytic film comprises the steps of: (A) obtaining a coating liquid by directly and partially removing, by means of centrifugal separation and/or filtration with a filter, salt contents and salt residues produced in polycondensation from a polymerization solution of a polymer electrolyte which is obtained by desalination polycondensation, and includes a hydrolyzable solubility-imparted group and an ionizable group, and has a density of the ionizable group of 1.0 mmol/g or more; (B) obtaining a film-like material on a base material by coating the base material with the coating liquid by a flow expanding method, and removing part of a solvent; (C) performing a proton exchange by bringing the film-like material on the base material into contact with an acidic aqueous solution; and (D) removing at least part of a low-molecular weight material with a molecular weight at polycondensation between 1000 and 30000 inclusive by bringing the film-like material on the base material into contact with a solvent. The steps are carried out in this order. |
