| 摘要 |
PURPOSE:To obtain a dry membrane simply at low cost by coating a substrate with a dope solution containing a copolymer, immersing the substrate in water to obtain a wet membrane, separating the wet membrane from the substrate and drying the membrane without causing shrinkage. CONSTITUTION:A substrate is coated with a dope solution containing 10-40% by weight of ethylene-vinyl alcohole copolymer having ethylene content of 10- 60mol%. The resulting substrate is immersed in water or aqueous solvent at a temperature of -5-10 deg.C to obtain a wet membrane having an average pore size of below 0.1mu. The wet membrane is separated from the substrate, placed in a frame to prevent shrinkage, and dried at a temperature of 10-40 deg.C. A preferred solvent for the dope solution is dimethyl sulfoxide or a mixture of dimethyl sulfoxide and water. It is possible to produce a composite membrane by using a porous non-woven fabric sheet or a non-woven fabric tube as the substrate. |
