POLYSULFONE MEMBRANE FOR PURIFYING BLOOD

摘要

A polysulfone membrane for purifying blood having excellent compatibility with blood and the process producing the membrane are disclosed. The membrane comprises a mixed polymer phase of a graft copolymer and/or block copolymer having a molecular weight of 3 x 10<5> daltons or more and comprising (A) a hydrophilic segment and (B) a hydrophobic segment (exclusive of polysulfone) in a total amount of from 0.5 to 30 parts by weight per 100 parts by weight of polysulfone, with the monomer unit ratio (A/B) between the segments A and B being from 0.5 to 5. The copolymer is preferably a graft copolymer where the hydrophilic segment is a polyvinylpyrrolidone segment and the hydrophobic segment is a polystyrene segment. The membrane can be prepared by applying a wet film formation process to a dope containing an appropriate solvent of the mixed polymer, such as N,N-dimethylacetamide. The membrane for purifying blood reduces cumbersomeness in the washing of the coagulated membrane during the film formation process and allows recovery of the solvent from the coagulating solution at a high recovery rate because the copolymer contained in the structure of the membrane is substantially not eluted into water contacted during the film formation process and the washing step.