| 摘要 |
PURPOSE:To form a laminate film wherein a microporous film and a reinforcing perforated base material are laminated without substantially changing the pore size and void ratio of the microporous film by forming the laminate film from the microporous film composed of ultrahigh MW polyolefin and the reinforcing perforated base material to fuse both of them at intermittent parts. CONSTITUTION:This laminate film consists of a microporous film composed of ultrahigh MW polyolefin and a reinforcing perforated base material both of which are fused at intermittent parts. The microporous film pref. has a piercing pore size of 0.001-0.5m and a void ratio of 30% or more. As ultrahigh MW polyolefin, a crystalline homopolymer or copolymer having a wt. average MW of 5X10 or more obtained by polymerizing ethylene or propylene is designated. As the reinforcing perforated base material, any one capable of being bonded to the microporous film such as a fabric, a nonwoven fabric, a porous film, a perforated sheet or a perforated film all of which are made of a thermoplastic resin can be used. The fabric to the used is formed from a tape obtained by uniaxially stretching a film made of high density polyethylene.
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