| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a crystallizable polymer microporous membrane that has a minute pore diameter, can efficiently catch fine particles of tens of nm size and has a high flux, to provide a method for manufacturing the crystallizable polymer microporous membrane that can consistently withstand stretching at a high magnification and to provide a filtration filter that has high resistance to pleat collapse. <P>SOLUTION: The method for manufacturing a crystallizable polymer microporous membrane includes a preform making step of making a preform by using a crystallizable polymer, an extrusion step of extruding the preform into the form of a sheet by an extrusion apparatus having a preform introduction part, a drawing part connected to the preform introduction part and a sector part connected to the drawing part and having a central angle of not less than 80° to not more than 160°, a rolling step of multistage rolling the sheet formed of the crystallizable polymer produced through the extrusion step, and a stretching step of stretching the sheet formed of the crystallizable polymer produced through the rolling step. <P>COPYRIGHT: (C)2012,JPO&INPIT |
