Patent ID: 6632366
Filing Date: 2003-10-14
Classification: B01D,C02F

Abstract:
A hollow fiber membrane comprising a cellulose compound as a membrane material, wherein the thickness of the membrane is 50 to 500 &mgr;m, a dense membrane surface having an average pore diameter of 0.001 to 0.05 &mgr;m exists on the internal and/or external surface thereof, the inside of the membrane is composed of a three-dimensional network porous structure having voids with an average pore diameter of 0.1 to 2 &mgr;m and a maximum value in the distribution of pore diameters of 0.5 to 5 &mgr;m, a tensile strength at break of the hollow fiber membrane is at least 3 MPa, a pure water permeation rate is 200 l/(m2h) or more at a transmembrane pressure of 100 kPa and at a temperature of 25Â° C., an elongation at break of the membrane is at least 15% and 70% by weight or more of the membrane material is cellulose acetate propionate or cellulose acetate butyrate.