| 摘要 |
PURPOSE:To attain to enhance a water pervious amount without shrinking a membrane, by immersing an aromatic polysulfonic acid membrane formed by a wet film forming process in a liquid having weak coagulating force before drying. CONSTITUTION:Aromatic polysulfone comprising a repeating unit represented by one of general formulae shown by the drawing is used. An aromatic polysulfone permselective membrane formed by a wet film forming process is immersed in a liquid I which is a poor solvent of said resin and compatible with a coagulation liquid and further immersed in a liquid II which is compatible with the liquid I and imcompatible with the coagulation liquid and the treated membrane is dried. In polysulfone, because water or an aqueous solution is utilized as the coagulation liquid, alcohols are pref. as the liquid I . As the liquid II, cyclohexane is used when ethyl alcohol is used as the liquid I . In drying, thermal drying is pref. performed after air drying. |
