| 摘要 |
PURPOSE:To obtain a separator having chemical stability, hydrophilic property, and flexibility by the procedure in which polyvinyl alcohol film is subjected to a hydrophilic group-providing treatment and then to a heat treatment in an solution of a water-soluble organic compound with hydroxyl group. CONSTITUTION:A PVA film, consisting of polyvinyl alcohol(PVA) film on the market and a core material, e.g., a nonwoven fablic, a mesh, etc., is dipped in an aqueous solution of an alkaline permanganate or a chromate for a hydrophilic group- providing treatment, in which hydrophilic -COOH group, etc., are formed, and then heat-treated in a solution of a water-soluble organic compound with hydroxyl group, e.g., glycerine, ethylene glycol, 1,3-butane diol, etc. For example, a 50mu- thick PVA film of a crystallinity of 0.27 is dipped in an alkaline potassium permanganate aqueous solution for 3min. for a hydrophilic group-providing treatment, washed with water, dried, and then treated in a triethylene glycol solution kept at 180 deg.C for 5min. to obtain a separator. |
