| 摘要 |
<p>A hollow porous membrane reduced in cost and excellent in separating properties, water permeability, and mechanical strength; and a process for producing, at low cost, the hollow porous membrane including a porous membrane layer having excellent adhesion to a support. The hollow porous membrane has a porous membrane layer having dense layers around the outer surface thereof and around the inner surface thereof, respectively. The process for producing the hollow porous membrane comprises continuously applying film-forming dopes, i.e., a first film-forming dope and a second film-forming dope, each comprising a material for the porous membrane layer and a solvent to the peripheral surface of a hollow support with annular nozzles to form superposed layers of the dopes and solidifying these film-forming dopes simultaneously. In the process for producing a hollow porous membrane by applying film-forming dopes comprising a material for the porous membrane layer and a solvent to the peripheral surface of a hollow support and solidifying the dopes to form a porous membrane layer, a hollow knitted cord formed from one multifilament yarn by circular knitting is used as the support.</p> |
