| 摘要 |
PROBLEM TO BE SOLVED: To obtain an ion exchange resin having excellent environmental resistance and a high cation exchange capacity by bringing a resin material into contact with sulfur dioxide gas, bringing the material into contact with fluorine gas in a specified temperature range, and immersing the treated membrane in an aqueous alkali solution. SOLUTION: A polyolefinic resin is brought into contact with 0.1-0.5 kg, per cm2 surface area of the resin material, of sulfur dioxide gas under a vacuum of 0.01-0.5 kg/cm2 and is reacted with a fluorine gas diluted with e.g. nitrogen gas to a concentration of 0.5-30 vol.% at temperatures of -10 to -180 deg.C to form an intermediate product on the surface of the resin. The resin is immersed in an aqueous alkali (e.g. sodium hydroxide) solution having a concentration of 0.001-18 N at temperatures of -20 to 150 deg.C to obtain a sulfonate-type ion exchange resin. The polyolefinic resin used is exemplified by a polyethylene, a polypropylene, or an ethylene/vinyl alcohol copolymer, and may be in the form of granules, a sheet, a film, a woven fabric, a nonwoven fabric, or the like. |
