Patent Number: 7,785,735

Title: Microporous composite membrane and its producing method and use

Abstract: A microporous composite membrane comprising a microporous polyolefin membrane and a polypropylene-based coating layer formed on at least one surface of the microporous polyolefin membrane, the polypropylene having a mass-average molecular weight within a range of 5,000-500,000, and solubility of 0.5 g or more in 100 g of toluene at a temperature of 25.degree. C., and the microporous composite membrane having air permeability (converted to the value at 25-.mu.m thickness) of 50-10,000 seconds/100 cc.

Inventors: Kaimai; Norimitsu (Kanagawa-ken, JP), Kobayashi; Shigeaki (Kanagawa-ken, JP), Kimishima; Kotaro (Kanagawa-ken, JP), Suzuki; Sadakatsu (Saitama-ken, JP), Ueki; Satoshi (Tokyo, JP), Yamada; Kazuhiro (Tochigi-ken, JP)

Assignee: Tonen Chemical Corporation

International Classification: H01M 2/16 (20060101)

Expiration Date: 8/31/12018