| 摘要 |
PURPOSE:To provide the title ion exchange membrane esp. suitable for electrolysis of alkaline aqueous solutions or alkali halides, enabling electrolysis to be made in highest current efficiency at lowest voltage, consisting of a laminate made up of the first film of a fluorine-contg. polymer and the specific second film. CONSTITUTION:The objective cation exchange membrane consisting of a laminate made up of (A) the first film of a fluorine-contg. polymer having sulfonic acid group and (B) the second film of fluorine-contg. polymer having recurring units of respective formulas I-III [Rf is 1-5C perfluoroalkyl; M is H or alkali metal; molar ratio II+III/I+II+III=0.12-0.25] with carboxylic group as ion exchange group, having large ion exchange capacity 5-50mu in thickness smaller than that of the first film. The ion exchange capacity of the second film is greater than that for the first film by 0.05-0.2meq./g dry resin. |
