| 摘要 |
PURPOSE:To obtain a membrane which has an extremely excellent hydrophilic property and is high in the rate of water penetration by immersing the filter membrane in a wetting agent made of PVA which has mol.wt. not less than two thousand and not more than forty thousand and 60-80% in saponification value and drying it. CONSTITUTION:A filter membrane is formed by a well-known film producing method by utilizing hydrophobic resin (e.g. polysulfone, polyether, polyphenylene oxide, polycarbonate, polyacetal and cellulose triacetate, etc.) as a stock. As the shape of the membrane, any one of a flat membrane, a cylindrical membrane and a hollow yarnlike membrane, etc., may be utilized which are manufactured by the ordinary film producing method. The manufactured filter membrane is immersed in PVA which has mol.wt. not less than two thousand and not more than forty thousand (preferably not less than five thousands and not more than twenty thousands) and 60-80% saponification value and thereafter dried. PVA contained in the filter membrane is regulated to the degree not less than 0.1% and not more than 15% for the weight of the whole filter membrane. The membrane which has an extremely excellent hydrophilic property and is high in the rate of water penetration can be obtained by this method. |
