PROCESS FOR PRODUCING A CELLULOSE ACETATE- TYPE PERMSELECTIVE MEMBRANE HAVING VERY HIGH WATER PERMEABILITY AND PROTEIN RETENTION

摘要

ABSTRACT OF THE DISCLOSURE.A process for producing a cellulose acetate-type permselective membrane having very high water-permeability and protein retention, which comprisescasting a dope comprising (a) 1 part by weight of cellu-lose acetate, and (b) 2 to 20 parts by weight of a mixedsolvent composed of (i) dimethylsulfoxide and (ii) atleast one water-soluble organic compound selected fromthe group consisting of monohydric alcohols having 2 to5 carbon atoms, dihydric alcohols of the formulaHO (RO)n H wherein R is an alkylene group having 2 or 3carbon atoms and n is an integer of 1 to 16, and carboxy-lic acids having 1 or 2 carbon atoms, the weight ratio ofsaid water-soluble organic compound to dimethylsulfoxidebeing not more than l; and solidifying the resulting rawmembrane with a coagulating solution.