| 摘要 |
<p>A porous hollow-fiber membrane which is suitable for use in applications such as, e.g., filtration, combines high rejection with water permeability, and has excellent mechanical strength; and a process for stably producing the membrane. The process for producing a porous multilayered hollow-fiber membrane comprises: using a nozzle for hollow-fiber molding having two or more annular orifices concentrically disposed to conduct annular multilayer melt extrusion in which a molten mixture of a thermoplastic resin and an organic liquid is ejected in a tubular form from each annular orifice, the molten mixtures ejected from adjacent annular orifices being different in composition; cooling/solidifying the resultant molten strand to form a hollow fiber; and then removing the organic solvent from the cooled/solidified hollow fiber by extraction. It is characterized in that the molten mixture to be ejected from at least one annular orifice contains inorganic fine particles incorporated by kneading besides the thermoplastic resin and the organic liquid, and that after the cooling/solidification, not only the organic liquid but the inorganic fine particles are removed by extraction.</p> |
