Sumitomo Chemical Company, Limited

Hirohiko Hasegawa

Yuzuru Saitou

Koichiro Watanabe

Jian Wang

Yasuo Shinohara

Daizaburo Yashiki

Yasunori Nishida

Hiroshi Shinoda

Takashi Yamada

The present invention provides a laminated porous film and a non-aqueous electrolyte secondary battery. The laminated porous film is a laminated porous film in which a heat-resistant layer comprising a binder resin and a filler is laminated on one or both of the surfaces of a porous film substrate mainly comprising a polyolefin, wherein a part occupied by at least one out of the binder resin and the filler is formed in the porous film substrate so as to touch the heat-resistant layer, and the total thickness of the occupied part is not less than 1% and not more than 20% of the overall thickness of the porous film substrate. The non-aqueous electrolyte secondary battery comprises the laminated porous film according as a separator.

Laminated porous film and non-aqueous electrolyte secondary battery

The present invention provides a method for producing a laminated porous film comprising a porous film substrate and a heat-resistant layer. The method comprises forming a heat-resistant layer mainly comprising a filler on the surface of the porous film substrate by applying a coating slurry comprising a solvent, a binder resin and the filler to the surface of the porous film substrate and then removing the solvent, wherein the coating slurry is prepared so as to have a contact angle of 75&#xb0; or more with an untreated porous film substrate, and the method comprises conducting surface treatment of a porous film substrate so that the contact angle of the coating slurry with the porous film substrate can be 65&#xb0; or less before applying the coating slurry to the surface of the porous film substrate.

Method for producing laminated porous film

A coating liquid according to the present invention comprises polyvinyl alcohol (PVA), boric acid and/or an organometallic compound having the ability of cross-linking PVA, an inorganic filler, a water-soluble compound having a carboxyl group and/or a sulfonic group, and water. According to the present invention, a coating liquid can be obtained which is useful in the preparation of a laminated porous film having suppressed powder fall-off and excellent heat shape stability.

Coating fluid, laminated porous film, and non-aqueous electrolyte secondary battery

As a laminated porous film realizing excellent handling properties in a low-humidity environment, a laminated porous film in which a layer containing a polymer is laminated on at least one side of a polyolefin porous film, satisfying the following (1) and (2) is provided. (1) When the laminated porous film cut into a rectangle having a length on a side parallel with a machine direction of 60 mm, and a length on a side parallel with the direction perpendicular to the machine direction of 40 mm is left still for 1 hour in an environment at a temperature of 23&#xb0; C. and a humidity of 50%, a lifting amount of the side parallel with the direction perpendicular to the machine direction is 8 mm or more. (2) When the laminated porous film cut into a rectangle having a length on a side parallel with a machine direction of 60 mm, and a length on a side parallel with the direction perpendicular to the machine direction of 40 mm is left still for 1 hour in an environment at a temperature of 23&#xb0; C. and a humidity of 5%, a lifting amount of the side parallel with the machine direction is 12 mm or less.

Laminated porous film, non-aqueous electrolyte secondary battery separator, and non-aqueous electrolyte secondary battery

Provided is a laminated porous film suitable as a non-aqueous electrolyte secondary battery separator, which includes a heat resistant layer excellent in morphological stability at a high temperature and ion permeability and more resistant to fall-off of a filler. A laminated porous film in which a heat resistant layer including a binder resin and a filler and a base porous film including a polyolefin as a principal component are laminated, wherein the filler included in the heat resistant layer substantially consists of an inorganic filler (a) having a primary particle diameter of 0.2 to 1 &#x3bc;m and an inorganic filler (b) having a primary particle diameter of 0.01 to 0.1 &#x3bc;m, and the particle diameter of secondary aggregates of the inorganic filler (b) is not more than 2 times the primary particle diameter of the inorganic filler (a) in the heat resistant layer.

Laminated porous film, method for producing same, non-aqueous electrolyte secondary battery separator, laminated electrode sheet, and non-aqueous electrolyte secondary battery

As a laminated porous film realizing excellent handling properties in a low-humidity environment, a laminated porous film in which a layer containing a polymer is laminated on at least one side of a polyolefin porous film, satisfying the following (1) and (2) is provided. (1) When the laminated porous film has left still for 1 hour in an environment at a temperature of 23&#xb0; C. and a humidity of 50%, a lifting amount of the side parallel with the direction perpendicular to the machine direction is 8 mm or more. (2) When the laminated porous film has left still for 1 hour in an environment at a temperature of 23&#xb0; C. and a humidity of 5%, a lifting amount of the side parallel with the machine direction is 15 mm or less.

Provided is a nonaqueous electrolyte secondary battery separator that has (i) an excellent ion permeability and (ii) reduced occurrence of a leak defect despite a small thickness. The nonaqueous electrolyte secondary battery separator includes a porous film containing polyolefin as a main component, the nonaqueous electrolyte secondary battery separator having a Gurley value within a range of 50 sec/100 cc to 200 sec/100 cc, the nonaqueous electrolyte secondary battery separator having a thickness within a range of 3 &#x3bc;m to 16 &#x3bc;m, the nonaqueous electrolyte secondary battery separator satisfying 0.85&#x2264;((S/S)+(S/S))/2&#x2264;0.91.

Nonaqueous electrolyte secondary battery separator, nonaqueous electrolyte secondary battery laminated separator, nonaqueous electrolyte secondary battery member, and nonaqueous electrolyte secondary battery

Provided is a nonaqueous electrolyte secondary battery laminated separator including a laminated porous film including a porous film and a porous layer. The piercing strength (S) of the laminated porous film satisfies Formula (1): 2 gf&#x2266;Sp&#x2212;S&#x2266;25 gf, and the piercing strength (Sp) of the porous film after removal of the porous layer from the laminated porous film satisfies Formula (2): 300 gf&#x2266;S&#x2266;400 gf. The nonaqueous electrolyte secondary battery laminated separator is excellent in output characteristic, shutdown characteristic, and piercing strength.

Nonaqueous electrolyte secondary battery laminated separator

The present invention provides a coating liquid, a laminated porous film and a method for producing a laminated porous film. The coating liquid comprises a binder resin, a filler and a medium, wherein the filler is a mixture comprising (a) a filler having a specific surface area of not less than 7 m/g and not more than 80 m/g and (b) a filler having a specific surface area of not less than 3 m/g and not more than 6 m/g in a filler (a) to filler (b) weight ratio of from 5:95 to 40:60. The laminated porous film is a laminated porous film in which a heat-resistant layer is laminated on one or both of the surfaces of a porous film substrate, wherein the heat-resistant layer is a heat-resistant layer formed by removing the medium from the coating liquid.

Coating liquid, laminated porous film, and method for producing laminated porous film

A porous film which is produced using a resin composition containing an ultra-high-molecular-weight polyolefin and a polyolefin wax having a weight average molecular weight of 3000 or less, in which the number of branches per 1000 carbon atoms that constitute the main chain of the polyolefin wax is 15 or less; a porous film which is produced using a resin composition containing an ultra-high-molecular-weight polyolefin and a polyolefin wax having a weight average molecular weight of 3000 or less, and which does not substantially contain a component that melts at a temperature of 60&#xb0; C. or lower; a laminated porous film which comprises one of the porous films and a heat-resistance porous layer laminated on at least one surface of the porous film; and a separator for batteries, which comprises the porous film or the laminated porous film.

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Niihama, Japan

Hirohiko Hasegawa