PRODUCTION OF SEMIPERMEABLE MEMBRANE

摘要

PROBLEM TO BE SOLVED: To produce a semipermeable membrane minimized in the amt. of polyvinyl pyrrolidone to be discarded and excellent in spinning properties. SOLUTION: In a method for producing a semipermeable membrane based on a polysulfone resin and two or more kinds of polyvinyl pyrrolidone resins different in mol.wt., the wt. ratio of the polyvinyl pyrrolidone resins to polysulfone in a membrane forming raw soln. is 20-35% and the temp. of a dry zone is spinning cap portion temp. -40 deg.C <= temp. of dry zone <= spinning cap portion temp. -15 deg.C and relative humidity is 60-95%.