Patent ID: 6372136
Filing Date: 2002-04-16
Classification: B01D,D01D,D01F

Abstract:
A cellulose acetate hollow fiber membrane, wherein the thickness of the hollow fiber membrane is 100 to 400 &mgr;m, the cross-section of the hollow fiber membrane is composed of a three-dimensional network part and a void part, the void part is positioned inside 10 &mgr;m or more from both internal and external surfaces of the membrane, the area occupied by the void part is in the range of 5 to 60% of the total cross-sectional area of the membrane, a dense layer having a surface average pore size of 0.001 to 0.05 &mgr;m exists on each of the internal and external surfaces of the hollow fiber, and a slit structure is observed on the internal surface of the hollow fiber with an electron microscope at a magnification of Ã—20,000.