摘要 |
<p>A porous film, a process for producing the same, a battery separator comprising the porous film, and a battery having incorporated therein the separator are disclosed. The porous film comprises a polyethylene and a polypropylene as the essential components, wherein the polyethylene content in the total weight of polyethylene and polypropylene is from 2 to 40% by weight and the polyethylene content is changed in the direction of the thickness of the film, and is produced by forming a laminate film comprising at least one polypropylene layer and at least one layer of a mixture of polyethylene and polypropylene as the essential components, the polyethylene content in the film being from 2 to 40% by weight, uniaxially stretching the laminate film at a low-temperature range of from -20 DEG C to 80 DEG C and then stretching the film at a high-temperature range of from 90 DEG C to 150 DEG C. <IMAGE></p> |
申请人 |
NITTO DENKO CORP., IBARAKI, OSAKA, JP |
发明人 |
NISHIYAMA, SOJI, IBARAKI-SHI, OSAKA, JP;HIGUCHI, HIROYUKI, IBARAKI-SHI, OSAKA, JP;MATSUSHITA, KIICHIRO, IBARAKI-SHI, OSAKA, JP;MATSUSHIMA, RYOICHI, IBARAKI-SHI, OSAKA, JP |