| 摘要 |
PURPOSE:Undrawn hollow filaments which will form pores by drawing is coated on their surfaces to form a thin film, then drawn to conduct industrially stable production of hollow fiber membranes bearing extremely thin separation membranes. CONSTITUTION:Undrawn hollow filaments to form pores by drawing are coated with a polymer sharing the separation function and drawn. A bit of drawing is effected at a temperature lower than the melting points of both yarn and coat polymers to whiten the filaments, then heat drawing is effected at a temperature higher than the whitening one, but lower than the polymers melt to form a thin separation layer on the surface of the hollow fibers.
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