| 摘要 |
PURPOSE:To obtain a membrane having a high salt removing rate by laminating a semipermeable ultrathin membrane and a membrane composed of a block or graft copolymer having a quarternized polyvinyl pyridine segment to a porous base material. CONSTITUTION:First, an aqueous solution containing a water-soluble polyvalent amino compound, having two or more primary or secondary amino groups in its molecule as a main component, is applied to a porous base material and a polyfunctional crosslinking agent is brought into contact with the coated layer to perform the interfacial polymerization and crosslinking thereof to obtain a composite semipermeable membrane, having a semipermeable ultrathin membrane. Next, a block copolymer, having a quaternized polyvinyl pyridine segment and a monovinyl aromatic polymer segment or a graft copolymer having quaternized polyvinyl pyridine and a water-insoluble polymer, is brought into contact with the composite semipermeable membrane as a membrane according to a water surface developing method to be closely bonded and laminated thereto. By this method, a membrane having a high salt removing rate to treated water containing a slat in low concn. is obtained. |
