POLYSULFONE RESIN HOLLOW FIBER

PURPOSE:The titled hollow fiber that has a five-layer structure consisting of the specific outer surface, the outer void layer, the intermediate layer, the inner void layer and the inner surface, thus being suitable for use as a membrane in ultrafiltration, because of its high flux and burst strength. CONSTITUTION:A polysulfone polymer solution containing glycols in a polar organic solvent of 15-35wt% polymer concentration is extruded through annular nozzles. In the meantime, a liquid that is miscible with the above solvent but does not dissolve the polysulfone polymer is used as a coagulant for the outer and inner surfaces and forced into the inside of the hollow part with an appropriate pressure. Then, the resultant fibers are made to run in air at a distance of 0.1-30cm, introduced into the external coagulation bath to produce the objective hollow fiber membranes that have a five-layer structure of the outer surface Ao, the outer void layer Bo, the intermediate layer C, the inner void layer Bi and the inner surface Ai, where the thickness ratio of the inner void layer to the outer one is 1.5-0.6, the total membrane thickness is 100-600mum, the flux is 3m /m .day or more and the fractionating molecular weight is less than 13,000.