POLYSULFONE-BASE HOLLOW-FIBER HEMOCATHARTIC MEMBRANE AND PROCESSES FOR THE PRODUCTION THEREOF

摘要

A polysulfone-base hemocathartic membrane which is improved in hemocompatibility, reduced in the bleeding of polyvinylpyrrolidone to the inner surface of the hollow-fiber membrane, and improved in separation characteristics; and processes for the production thereof. Constitution: a polysulfone-base hollow-fiber hemocathartic membrane having a selective separation layer present on the inner surface side of the hollow-fiber membrane and containing polyvinylpyrrolidone, wherein the polyvinylpyrrolidone content is 1 to 10 wt.%, 5 to 50 % of the polyvinylpyrrolidone is soluble in water, and the concentration of polyvinylpyrrolidone at the surface of the hollow-fiber membrane lies in the range of 30 to 45 %. A process for the production of a polysulfone-base hollow-fiber hemocathartic membrane, which comprises ejecting a solution containing a polysulfone polymer and polyvinylpyrrolidone and having a viscosity of 1500 to 6000 mPa . s at a rate of ejection of 90 m/min or below and drawing the resulting filament at a draft ratio of 1.1 to 1.9. Another process for the production of a polysulfone-base hollow-fiber hemocathartic membrane, which comprises producing a hollow-fiber membrane by spinning from a solution containing a polysulfone polymer and polyvinylpyrrolidone, and insolubilizing part of the polyvinylpyrrolidone, preceded by, if necessary, the extractive removal of the polyvinylpyrrolidone from the hollow-fiber membrane by washing with a solvent.