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AssigneeAsahi Kasei Kogyo Kabushiki Kaisha
InventorsSeiichi Manabe, Michitaka Iwata, Mamoru Inoue
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A porous regenerated cellulose hollow fiber obtained by a micro-phase-separation method is described. The hollow fiber is characterized in that the viscosity average molecular weight is at least 5.times.10.sup.4, each of the average pore diameter D.sub.1 on the inner wall surface of the hollow fiber and the average pore diameter D.sub.2 on the outer wall surface is 0.02 to 10 .mu.m, the in-plane porosity Pr on the outer wall surface is at least 10%, and the hollow fiber comprises a wall thickness portion having pores piercing therethrough between the inner wall surface and outer wall surface and a hollow portion extending continuously over the entire fiber length. The hollow fiber is prepared by a process characterized in that at the steps of extruding a cuprammonium solution of a cellulose from an annular spinning orifice and coagulating, regenerating and water-washing the extrudate, the spinning solution is extruded from an outer annular spinning orifice and a liquid having a coagulating action to the spinning solution is extruded from a central spinning orifice, and micro-phase-separation is caused to occur before the coagulation.
A porous regenerated cellulose hollow fiber characterized by an inner wall surface, an outer wall surface, a hollow portion extending continuously over the entire fiber length, and a wall thickness portion having pores piercing therethrough between said inner wall surface and outer wall surface , said hollow fiber having about 10.sup.5 to about 10.sup.9 of fine particles and agglomerates thereof per cm.sup.2 of said hollow fiber area wherein said fine particles have a diameter of 0.02 to 1 .mu.m, the cellulose molecules of said fiber having a viscosity average molecular weight of at least 5.times.10.sup.4, said pores having an average pore diameter D.sub.1 and an in-plane porosity Pr on the inner wall surface of said hollow fiber, an average pore diameter D.sub.2 and an in-plane porosity Pr on the outer wall surface of said hollow fiber and an average pore diameter D.sub.3 and an in-plane porosity Pr of the intermediate part of said wall thickness portion, each of the average pore diameters D.sub.1 and D.sub.2 being in the range of 0.02 to 10 .mu.m and the in-plane porosity Pr on the outer wall surface of the hollow fiber being at least 10%.
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