Toray Industries, Inc.

Nobuyasu Kai

Akimitsu Tsukuda

Kei Ikoma

Hiroko Tanaka

Keiichi Kamon

Naoki Imazu

A low cost porous film has high thermal dimensional stability and good adhesion with electrodes and also has excellent battery characteristics. The porous film includes a porous base and a porous layer containing particles A and particles B disposed at least on one side thereof, wherein the particles A contain a polymer having at least one selected from the monomer unit group a that consists of fluorine-containing (meth)acrylate monomer units and silicon-containing monomer units whereas the particles B are inorganic particles.

Porous film including porous base and porous layer having inorganic particles and resin particles containing fluoro (meth)acrylate-containing or silicon-containing polymer, separator for secondary batteries, and secondary battery

A porous film includes a porous substrate, and a porous layer laminated on at least one surface of the porous substrate. The porous layer contains an organic resin different from a resin constituting the porous substrate. A height of a projection of the porous layer in an interface between the porous substrate and the porous layer is 200 nm or more, and a distance between projections is 1 &#x3bc;m or more.

Porous film, separator for secondary batteries, and secondary battery

At low cost, a porous film has high thermal film rupture resistance and outstanding battery characteristics. The porous film has a porous layer on at least one surface of a porous substrate, and if the surface porosity of the porous layer is defined as &#x3b1; and the cross-sectional void ratio of the porous layer is defined as &#x3b2;, then &#x3b1;/&#x3b2; does not exceed 90%.

Porous film, separator for rechargeable battery, and rechargeable battery

A porous film includes a porous substrate, and a porous layer provided on at least one surface of the porous substrate. The porous layer includes the following resin A and resin B, and satisfies that &#x3b1;/&#x3b2; is less than 1.0, where &#x3b1; is a surface opening ratio of the porous layer and &#x3b2; is a cross-sectional porosity of the porous layer. The resin A is a resin having a melting point of 150&#xb0; C. or higher, or a resin having no substantial melting point. The resin B is a resin having a melting point of lower than 150&#xb0; C., or an amorphous resin.

A secondary battery separator includes a porous base material; and a porous layer stacked on at least one surface of the porous base material, the porous layer being mainly composed of inorganic particles, and two or more organic resins having different melting points, the porous layer including a fluororesin as at least one of the organic resins, the secondary battery separator satisfying at least one of (A) and/or (B): (A) the porous layer has a melting point of 130&#xb0; C. or higher and 20&#xb0; C. or higher and lower than 130&#xb0; C.; and (B) the porous layer has a melting point of 130&#xb0; C. or higher, and includes an amorphous organic resin.

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Otsu, Japan

Nobuyasu Kai