Title:
COVERED MICROPOROUS FILM
Document Type and Number:
Japanese Patent JP3497531
Kind Code:
B2
Abstract:
PURPOSE: To maintain the electrical properties and improve the mechanical strength of a microporous film by covering the film with a high-molecular organic substance which contains an alkali metal salt.
CONSTITUTION: A polyolefin resin such as high-density polyethylene with a viscosity average molecular weight of 200,000 to 5,000,000 or a blend thereof is mixed with an inorganic fine powder such as silicic acid powdered finely and an organic liquid such as dioctyl phthalate and melt kneaded. After the extraction of the inorganic powder and the organic liquid with, respectively, caustic soda and an organic solvent, the mixt. is extrusion molded, followed by drying and monoaxial stretching or, when necessary, biaxial stretching to obtain a microporous film (A). Then the microporous film (A) is immersed in a soln. prepared by dissolving a high-molecular organic substance such as polyethylene oxide with a viscosity average molecular weight of 4,000,000 or below which contains a salt of an alkali metal such as lithium or sodium in an organic solvent such as methylene chloride and further dissolving propylene carbonate and a lithium salt in it, followed by drying to obtain a covered microporous film having an air permeability of 1,500sec/100cc or below a maximum pore diameter of 0.01 to 2.0μm, a void percentage of 10 to 80% and a film thickness of 10 to 50μm.
Inventors:
Koichi Agata
Application Number:
JP20507093A
Publication Date:
February 16, 2004
Filing Date:
August 19, 1993
Export Citation:
Assignee:
Asahi Kasei Chemicals Corporation
International Classes:
C08J7/04; H01G9/02; H01M2/16; (IPC1-7): C08J7/04; H01G9/02; H01M2/16
Domestic Patent References:
| JP3245456A | ||||
| JP4985525A |
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