| abstract |
PURPOSE: To obtain a dry semipermeable membrane excellent in heat resistance, chemical resistance, and mechanical characteristics by a method in which a polysulfone composed of a polymer with specific composion is molded into a liquid film, dipped in an aqueous liquid for coagulation and then dried. n CONSTITUTION: A solution of a polysulfone polymer composed of a repeating unit of the formulas (I), (II), and (III) (where Ar and Ar' are each a substituent with phenyl, diphenyl, or a nondissociation group) is flowed onto a supporter to form a liquid film or a hollow liquid film. Then, the liquid film or hollow liquid film is dipped in a liquid having a surface tension below the critical surface tension of the polysulfone and also a compatibility with the polysulfone solution in such a way as to coagulate it into a 0.01W1 micron film having a water permeability of 15W 2,500l/m 2 hr.kg/cm 2 . Then, the film thus obtained is then dipped in a warm water or water-donimated aqueous liquid of 80°C or higher for one minute to 3 hours and then dried at a temperature below the thermal denaturation temperature of the polysulfone film. Thus, a semipermeable membrane having an excellent separating characteristics for ultrafiltration, dyalysis, baterry, etc., can be obtained. n COPYRIGHT: (C)1982,JPO&Japio |