POROUS POLYSULFONE MEMBRANE AND PROCESS FOR PRODUCING THE SAME

摘要

A porous polysulfone membrane which has a high water permeation velocity and is excellent in wet heat resistance and repeated water permeation. The membrane is produced from a mixed polymer composed of a polyaryl sulfone and a polyether sulfone in a weight ratio of 9/1 to 1/9 and has a polymer network structure wherein numerous fine pores run through from one surface of the membrane to the other surface thereof. The membrane is composed of a dense layer containing numerous pores with diameters of 0.01-1 mu m and having a separating function and a gradient supporting layer which supports the dense layer and contains pores with diameters of 1-100 mu m in such a manner that each pore diameter increases continuously along the direction from the dense layer side thereof to the other side thereof and the fractionation particle diameter of the membrane is 0,5 mu m or less.