| 摘要 |
PURPOSE:To obtain an ion exchange membrane, having three laminated layers in which each layer consists of a fluorine-containing polymer having ion exchange groups and satisfies specific condition, with excellent mechanical strength and dimensional stability as well as electrochemical characteristics and particularly suitable for electrolyzing aqueous solutions of an alkali chloride. CONSTITUTION:An ion exchange membrane obtained by successively laminating (A) the first layer having carboxylic acid groups on the cathode side, (B) the second layer having preferably carboxylic acid groups and/or sulfonic acid groups are ion exchange groups, lower resistance than that of the first layer and >=50% membrane thickness based on the total membrane and (C) the third layer having preferably sulfonic acid groups as the exchange groups, a swelling degree >=5% higher than that of the second layer and specific resistance >=30OMEGA.cm lower than that of the second layer. The respective layers have preferably membrane thicknesses as follows. 10-40mu for the first layer, 100-150mu for the second layer and 10-50mu for the third layer.
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