Hollow porous membrane and process for producing the same

Abstract

A hollow porous membrane with a reduced cost and excellent separation characteristic, water permeability, and mechanical strength and a process of producing the hollow porous membrane with an excellent adhesive property between a support and a porous membrane layer at a low cost are provided. The hollow porous membrane includes a porous membrane layer in which dense layers are disposed in the vicinities of an outer surface and an inner surface. In the process of producing the hollow porous membrane, membrane-forming dopes of a first membrane-forming dope and a second membrane-forming dope, which contain the material of the porous membrane layer and a solvent, are successively applied and stacked onto the outer circumferential surface of a hollow support and the applied membrane-forming dopes are simultaneously coagulated. In the process of producing the hollow porous membrane, a porous membrane layer is formed by applying a membrane-forming dope containing a material of the porous membrane layer and a solvent to the outer circumferential surface of the hollow support and coagulating the applied dope, and a hollow braid obtained by circularly knitting a yarn formed of multi-filaments is used as the support.