| 摘要 |
PROBLEM TO BE SOLVED: To obtain a fluid-penetrable finely porous film whose performance can be controlled for each target and which has a high performance, a reduced thickness and excellent productivity, by stretching a specific composition containing anα-olefin-carbon monoxide copolymer. SOLUTION: This fluid-penetrable fine porous film comprises at least one thermoplastic resin layer consisting mainly of (A) anα-olefin-carbon monoxide copolymer resin and having a crystal melting point of 140-250 deg.C, and has a porosity of 30-80%, an air permeability of 5-2,000 sec/100 cc and a 10% contraction temperature of >=100 deg.C. The film is obtained by extruding a composition consisting mainly of the component A and/or (B) a polyolefin resin having a crystal melting point of 80-240 deg.C and 85-10 pts.vol. of (C) an inactive extractable organic liquid having a viscosity of <=1,000 cPs at 200 deg.C through a die, quenching and solidifying the extruded film with a heat-conductive medium, stretching the film at least in one direction in a surface-stretching ratio of 2-50 times under a specific temperature condition, and then extracting the component C. |
