Asahi Kasei Kogyo Kabushiki Kaisha

Mamoru Inoue

Seiichi Manabe

Michitaka Iwata

A porous regenerated cellulose hollow fiber is obtained by a micro-phase-separation method. 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.

Process for the preparation of a porous regenerated cellulose hollow

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.

Porous regenerated cellulose hollow fiber and process for preparation

A porous regenerated cellulose membrane consisting essentially of cellulose molecules having a viscosity average molecular weight of at least about 5.times.10.sup.4, the crystalline region of the cellulose molecules being substantially cellulose II crystal, cellulose III-2 crystal or the mixture thereof and having a degree of crystal orientation at a face of (101) in the crystalline region in the direction of the surface of the membrane of at most about 40%, the membrane having a dynamic modulus at 30.degree. C. measured with a frequency of 110 Hz of at least about 1.5.times.10.sup.8 (100-pr.rho.) dyn/cm.sup.2 wherein Pr.rho. is a porosity by percentage, a mean pore size represented by D(.mu.m) of about 0.01 .mu.m to about 20 .mu.m and at the same time a porosity in a plane of at least one plane of at least about 30% or a number of pores in a plane per 1 cm.sup.2 of about 6.times.10.sup.5 /D to about 3.times.10.sup.7 /D; and a process for preparing the same.

Growing community of inventors

Nobeoka, Japan

Mamoru Inoue