| 摘要 |
PROBLEM TO BE SOLVED: To provide a porous film composed of a high molecular weight polyolefin hard to extrusion-mold, and a manufacturing method thereof. SOLUTION: The porous polyolefin film is obtained by melt-kneading by a twin-screw extruder a resin composition comprising a polyolefin having a viscosity-average molecular weight of at least 300,000 with a non-reactive gas, removing the non-reactive gas from a discharge port fitted to the twin-screw extruder, extruding a dense polyolefin resin composition, cooling and solidifying the extruded polyolefin resin and subjecting the cooled and solidified polyolefin resin composition to a treatment for forming a porous structure. The manufacturing method of the porous polyolefin film is also provided. |
