Mitsubishi Chemical Corporation

Mitsubishi Plastics, Inc.

Hiroto Yamada

Tomoyuki Nemoto

Kouji Takegawa

The viscosity stability in forming a slurry of one or metal components selected from water-insoluble metal oxides and metal salts is improved, and using the resultant slurry, a coating layer is formed on a polyolefinic resin porous film to give a multilayer porous film having excellent surface smoothness. The multilayer porous film has, as layered on at least one surface of a polyolefinic resin porous film, a coating layer that contains one or more metal components selected from water-insoluble metal oxides and metal salts, and a resin binder, wherein the content of water-soluble calcium contained in the metal components is 3 ppm by mass or less.

Multilayer porous film, separator for non-aqueous electrolyte secondary battery, non-aqueous electrolyte secondary battery, slurry, and coating liquid

An alumina slurry containing alumina dispersed in a dispersion medium, the alumina having an average primary particle diameter of 0.1 &#x3bc;m or more and 1.0 &#x3bc;m or less, the alumina satisfying the following condition (1), and the slurry having a content of the alumina of 30% by mass or more and 70% by mass or less and a content of water in the dispersion medium of 50% by mass or more: condition (1): in relationship of a pore diameter r1 (&#x212b;) and a pore volume Dv1 (mL/g) of the alumina measured by a nitrogen desorption method based on JIS Z8831-2 (2010), the pore volume Dv1(80) at r1=80 and the maximum value Dv1(M) of Dv1 in a range 20&#x2264;r1&#x2264;80 satisfy Dv1(M)&#x3e;Dv1(80).

Alumina slurry

There is provided a multilayer porous film that includes a covering layer formed from a coating liquid on at least one surface of a porous film. The coating liquid has high stability and coatability. The covering layer does not decrease the intrinsic high air permeability of the porous film and has high heat resistance and adhesiveness. The multilayer porous film has excellent handleability as a battery separator without causing curling. The multilayer porous film includes the covering layer on at least one surface of a porous polyolefin resin film. The covering layer is formed from a coating liquid and contains a filler and a resin binder. The multilayer porous film satisfies the following conditions 1) and 2): 1) the filler has an average circularity of 0.3 or more and less than 0.7; and 2) an acid component in the coating liquid has a first acid dissociation constant of 5 or less and has no second acid dissociation constant or a second acid dissociation constant of 7 or more in a dilute aqueous solution at 25&#xb0; C.

Multilayer porous film, separator for nonaqueous electrolyte secondary battery, and nonaqueous electrolyte secondary battery

The present invention produces a laminated porous film which improves the stability of an aqueous dispersion of a metal oxide without lowering battery characteristics, while having high binding properties and excellent heat resistance. This laminated porous film exhibits excellent characteristics when used as a separator for batteries. This laminated porous film is produced by forming a porous coating layer on at least one outer surface of a resin porous film, which is formed of a single layer or a laminate of a plurality of layers, by applying a coating liquid that contains a metal oxide, a resin binder and a volatile acid thereto and drying the applied coating liquid. The coating liquid is prepared so that the difference between the pH (pH) of the coating liquid and the pH (pH) of the coating layer is not less than 2.

Method for producing laminated porous film, and laminated porous film

Provided is a multilayer porous film that has extremely high powder fall-off resistance and superior electrolyte solution adsorptivity and heat resistance and exhibits superior properties when used as a battery separator without decreasing the high air permeability of a porous film. The multilayer porous film includes a polyolefin-based resin porous film and a coating layer containing a filler and a resin binder on at least one surface of the polyolefin-based resin porous film. The amount of particles with particle sizes of less than 0.2 &#x3bc;m (D) in the filler is 1% or more, and the specific surface area of the filler is 5 m/g or more and less than 10 m/g. The multilayer porous film satisfies a particular condition.

Multilayer porous film, separator for nonaqueous electrolyte secondary batteries, and nonaqueous electrolyte secondary battery

The present invention is capable of providing a multilayer porous film used as a separator for a non-aqueous electrolyte secondary battery. A multilayer porous film which is obtained by laminating a coating layer that contains a filler and a resin binder on at least one surface of a polyolefin resin porous film that serves as a base layer. The ratio of the average particle diameter (Du) of the filler within 25% of the thickness of the coating layer from the surface of the multilayer porous film to the average particle diameter (Db) of the filler within 25% of the thickness of the coating layer from the interface with the base layer, namely, Du/Db is 1.2 to 10; and the average particle diameter (Du) is 0.5 &#x3bc;m or less.

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Ogaki, Japan

Hiroto Yamada