Toray Battery Separator Film Co., Ltd.

Toray Industries, Inc.

Yoshitaka Ayuzawa

Naoki Mizuno

Michihiko Irie

Masanori Nakamura

A method produces a composite porous membrane including a porous membrane A formed of a polyolefin-based resin; and a porous membrane B containing a heat-resistant resin and laminated on the porous membrane A, including: (i) applying a heat-resistant resin solution onto a base film, followed by passing the coated film through a low-humidity zone, and then through a high-humidity zone to form a heat-resistant resin membrane on the base film; and (ii) bonding together the heat-resistant resin membrane formed in step (i) and a porous membrane A formed of a polyolefin-based resin, followed by converting the heat-resistant resin membrane into a porous membrane B by immersion in a solidification bath, and washing and drying the same to obtain the composite porous membrane.

Method of producing composite porous membrane

A composite porous membrane is a composite porous membrane, wherein a porous membrane B including a heat-resistant resin is laminated on the surface of a polypropylene resin of an outermost layer of a porous membrane A composed of at least one layer, wherein at least one of the outermost layers comprises the polypropylene resin. The composite porous membrane satisfies a particular range of peeling strength at the interface between the porous membrane A and the porous membrane B and a particular range of difference between air resistance of the whole composite porous membrane and air resistance of the porous membrane A, provided that the porous membrane A satisfies a particular range of average pore size and porosity.

Growing community of inventors

Ohtsu, Japan

Yoshitaka Ayuzawa