| 摘要 |
<p>A process for producing a porous polymer film, having many fine voids which are flat in the thickness direction, comprises forming many fine cracks in a stretchable polymer composition having a fine phase separation structure by mechanical deformation or chemical treatment, heating the thus treated polymer composition to its stretching temperature under tension, and then stretching the polymer composition at the stretching temperature. The polymer composition preferably contains a material which is fluid at the stretching temperature.</p> |
