| 摘要 |
PROBLEM TO BE SOLVED: To provide a multilayered porous film made of a thermoplastic resin, which is constituted so as to prevent an oil component absorbed from one side from passing through the other side though having high oil absorbability and controls oxygen permeability within a range of 2,000-30,000 nmol/(m<SP>2</SP>×s×100 kPa), with high productivity. SOLUTION: This multilayered porous film made of a thermoplastic resin is constituted by laminating at least one non-porous film layer (X) and at least one porous film layer (Y) having open pores with a void ratio of 20-80%. The porous film layer (Y) comprises a thermoplastic resin composition (C) containing a thermoplastic resin (A) and anα-olefin copolymer (B<SB>1</SB>) and/or a diene copolymer (B<SB>2</SB>) and has open pores communicating with the region of theα-olefin copolymer (B<SB>1</SB>) and/or the diene copolymer (B<SB>2</SB>) obtained by molding the thermoplastic resin composition (C) by a specific processing method. COPYRIGHT: (C)2005,JPO&NCIPI
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