Title:
POROUS FILM, PRODUCTION THEREOF, AND USE THEREOF
Document Type and Number:
Japanese Patent JPH05331306
Kind Code:
A
Abstract:
PURPOSE:To obtain a porous film excellent in tensile modulus, appearance, etc., and uniform in thickness by forming into a film a composition comprising polypropylene and polyethylene having a specific mol.wt., heating the film, and monoaxially stretching the resulting film, followed by further stretching. CONSTITUTION:A film is produced from a composition comprising 10-90wt.% polypropylene and 90-10wt.% polyethylene in which the ratio of the weight- average mol.wt to the number-average mol.wt. (Mw/Mn), both measured by high-temp. gel permeation chromatography, is 10 or lower. The film is heated ion the temp. range of the melting point of the polyethylene to [(melting point of the polypropylene)+10 deg.C]. Monoaxial stretching is then conducted at -20 to 60 deg.C to make the film porous, followed by further stretching in the temp. range of 60 deg.C to [melting point of the polyethylene)-5 deg.C], thereby giving the porous film. It is suited for use as a battery separator.
Inventors:
HIGUCHI HIROYUKI
MATSUSHITA KIICHIRO
EZOE MINORU
SHINOMURA TOSHIHIKO
MATSUSHITA KIICHIRO
EZOE MINORU
SHINOMURA TOSHIHIKO
Application Number:
JP263693A
Publication Date:
December 14, 1993
Filing Date:
January 11, 1993
Export Citation:
Assignee:
NITTO DENKO CORP
International Classes:
B29C55/04; C08J9/00; C08L23/00; C08L23/12; H01M2/16; B29K23/00; B29K105/04; B29L7/00; (IPC1-7): C08J9/00; B29C55/04; H01M2/16