Oblon, Spivak, McClelland, Maier & Neustadt
Porous film
 Disclosed herein is a porous film having a thickness of 90 .mu.m or less obtained by uniaxially stretching a film produced by blow-extruding a composition comprising a linear polyethylene, filler and a radical forming agent, the bending resistance of the porous film in both the machine and transverse directions being 50 mm or less, the moisture permeability of the porous film being 1500 g/m.sup.2 .multidot.24 hr or above, and the surface strength of the porous film satisfying the following relation (I): EQU Surface strength (kg).gtoreq.35.times.film thickness (mm) (I) and the process for producing the porous film defined above. 
Mitsubishi Kasei Corporation
B C B B Y Y C B Y Y
B29K C08J B29K B29K Y10T Y10T C08J B29C Y10T Y10T
additional inventional additional additional additional additional additional inventional additional additional
Minoru Tasuku Kazuhiro Toshio
Kashino Suzuki Kato Fujii