| 摘要 |
PURPOSE:To obtain a porous membrane capable of removing the occurrence of a part having low pore density, having high permeation rate of a liquid and a gas and useful for precise filtration membrane, etc., by melting and extruding a crystalline thermoplastic polymer from a nozzle into a gas and treating the melted polymer under specific conditions. CONSTITUTION:A crystalline thermoplastic polymer such as 4-methylpentene-1- based polymer is melted and extruded from a nozzle such as a hollow fiber- spinning nozzle into a gas having 1-10% oxygen concentration using a gas having <=10mol% oxygen concentration as a core agent so as to give a hollow yarn-like shape, and then, the molten polymer is solidified by cooling and drawn to provide the objective porous membrane. |
