POROUS MEMBRANE AND MANUFACTURING METHOD THEREFOR

摘要

PROBLEM TO BE SOLVED: To prepare a porous membrane which has high water permeability and few faulty spots and is excellent in performance and quality. SOLUTION: The excellent porous membrane has high water permeability (WF) of≥20 (m3/m2/h/MPa),≤20% index of pore size dispersion on the exterior surface and few faulty spots. The method for manufacturing the porous membrane comprises the steps of: using a membrane forming stock solution obtained by dissolving a membrane base material polymer in a solvent; filtering the membrane base material polymer by using a filter having 0.1 to 50μm mesh size; extruding the filtered polymer to such a gas phase that the difference (T1-T2) between the surface temperature (T1) of a nozzle and the dew point (T2) is higher than 0°C; making the extruded polymer pass through a high-humidity atmosphere of≥60% relative humidity; and solidifying the polymer thus wetted in a non-solvent. COPYRIGHT: (C)2005,JPO&NCIPI