| 摘要 |
<p>A thin porous film which is satisfactory in moisture permeability and air permeability and has an improved balance between machine-direction strength and transverse-direction strength; and a process for producing the film. The process comprises forming a resin composition comprising 25 to 70 wt.% polyolefin resin and 75 to 30 wt.% inorganic filler into a film and stretching the resultant film 1.2 to 3 times in the transverse direction by the gear stretching method to thereby form pores. The porous film has a ratio of the machine-direction strength to the transverse-direction strength of from 0.25 to 4.0, an air permeability of 1,000 sec/100 cc or less, a moisture permeability of at least 2,000 g/m2 •24 hr, and a basis weight of 7 to 35 g/m2.</p> |
