| 摘要 |
PURPOSE:A thermoplastic resin is drawn in a specific medium at a specific temperature to give porous thermoplastic hollow fiber of high porosity with uniform through-holes of a large diameter. CONSTITUTION:Hollow filaments of polyethylene, poly(4-methyl-pentene-l), polyvinylidene fluoride or an ethylene-polyfluoroethylene copolymer are drawn at a temperature below -100 deg.C in N2, O2, Ar, CO, CH4 or C2H6. The drawing temperature is required to be lower than the temperature which is 50 deg.C higher than the boiling point of the medium such as N2, thus uniform through-holes are formed, even when a thermoplastic resin or low elastic recovery is employed.
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