Patent ID: 6019925
Filing Date: 2000-02-01
Classification: B01D

Abstract:
A method for producing stable and storable cellulosic dialysis membranes for the low, middle, or high flux range with UFR values of 4 to 15, 15 to 50, or more than 50 ml/h m.sup.2 mm Hg, respectively, in the form of flat, tubular, or hollow fiber membranes, the method comprisingproducing a spinning solution composed of 3 to 40 parts of one or more of cellulose with a degree of polymerization (DP) greater than 300 or modified cellulose with a degree of polymerization (DP) greater than 200, 97 to 60 parts of a mixture of tertiary amine oxide and one or more additional liquids, optional one or more stabilizers, optional one or more pore formers, and optional spinning solution additives,extruding the spinning solution through a spinneret into a regenerating bath at a temperature of 10 to 95.degree. C., with the takeoff speed being at least 30 m/min,single stage or multistage washing or extraction of the resultant membranes to remove the amine oxide and soluble additives to a content of less than 10 ppm,and drying to obtain the flat, tubular or hollow fiber membrane.