| 摘要 |
PURPOSE:To obtain a multi-layer microporus membrane suitable for use in filtering a soln having a wide particle size distribution, by applying a soln. of different high-molecular materials dissolved in a solvent comprising a good solvent and a poor solvent or a soln. or the same kind of a high-molecular material dissolved therein at different concn. to a substrate in a multi-layer coating and drying it. CONSTITUTION:At least one high-molecular material selected from among nitrocellulose, a cellulose fatty acid ester, a cellulose mixed fatty acid ester, a polyamide resin, a polycarbonate resin, polyvinyl chloride resin and a cellulose there resin is prepd. Separately, a solvent comprising a good solvent for said high-molecular material and a poor solvent therefor and/or a non-solvent is prepd. A soln. of different high-molecular materials dissolved in the solvent or a soln. of the same kind of the high-molecular material dissolved therein at different concn. is prepd. and cast on a support simultaneously or in sequence in a multi-layer coating way and dried to obtain the desired multi-layer microporous membrane. |
