| 摘要 |
PURPOSE:To provide an ion exchange membrane capable of stably directly producing sodium hydroxide of a high concentration of up to the maximum concentration of 55wt.% for a long time in high performance in an ion exchange membrane salt electrolysis. CONSTITUTION:An ion exchange fluororesin membrane is characterized by disposing at least two layers (i=1) simultaneously satisfied with an expression 1, D1>Di+1 and with an expression 2, D1XTi+1>Di+1XT1 and having the outermost layer diffusion coefficient of 10<-8>cm<2>/sec on the side of the cathode side. D1, T1 are the diffusion coefficient (cm<2>/sec) of the number i surface layer and a thickness (cm), respectively. |
