PURPOSE: To introduce a carboxylic acid group in high efficiency, and to obtain a useful ion-exchange membrane having carboxylic acid group, by reacting a fluorine-based ion exchange membrane having a specific functional group with a mineral acid, and hydrolyzing the reaction product.
CONSTITUTION: The raw film of a fluorine-based ion exchange membrane having -CFI- group and/or -CF2I group is made to react with a mineral acid, and then hydrolyzed. The raw film is preferably made of a perfluorocarbon polymer containing 4W40wt% iodine, and more preferably having functional group bonded to the terminal of the side chain. The mineral acid is chlorosulfonic acid, etc., and the reaction is carried out at 100W250°C in the presence of ≥0.1mol% reaction reagent based on the iodine in the raw film. The obtained ion exchange membrane is preferably the one containing carboxylic acid group within 1μ from the surface in an amount of ≥0.2m-equivalent/lg of dry film (H-type).
| JPS6162031 | PHOTOSENSITIVE SILVER HALIDE MATERIAL |
NAKAHARA AKIHIKO
ITOU JIYUNICHI
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