Porous film and method for producing same
AssigneeTokyo Ohka Kogyo Co., Ltd.
InventorTsukasa SUGAWARA
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Abstract
Provided are a porous film having excellent surface smoothness and a method for producing the same. The surface roughness of a porous film of polyvinylidene fluoride, polyethersulfone, polyimide and/or polyamide-imide is Ra 30,000 Å or less. The opening diameter of the porous film is preferably from 100 nm to 5000 nm. The method for producing a porous film preferably includes a step for kneading a varnish containing fine particles and at least one resin selected from the group consisting of polyvinylidene fluoride, polyether sulfone, polyamic acid, polyimide, polyamide-imide precursor, and polyamide-imide. The varnish preferably has a viscosity at 25° C. of 0.1-3 Pa·s, a solids fraction concentration of 10-50 mass %, and a fine particle average particle size of 10-5000 nm.
Claims19
1-6. (canceled)
A single layer porous film in a laminated body comprising the single layer porous film and a support or an electrode,
- wherein the single layer porous film consists of:
- a film selected from the group consisting of a polyvinylidene fluoride film, a polyethersulfone film, a polyimide film and a polyamide-imide film,
- a front surface and a rear surface, wherein the front and rear surfaces communicate with each other,
- a surface having an opening portion, wherein the opening portion comprises at least one spherical pore having a curved surface, and the curved surface comprises a true-spherical shape or a substantially true-spherical shape, and
- a surface roughness Ra of 30000 Å or less, and
- wherein the single layer porous film is laminated on the support or the electrode such that the surface roughness Ra of 30000 Å or less adheres the single layer porous film to the support or the electrode.
A film comprising a single layer porous film and a support,
- wherein the single layer porous film consists of:
- a film selected from the group consisting of a polyvinylidene fluoride film, a polyethersulfone film, a polyimide film and a polyamide-imide film,
- a front surface and a rear surface, wherein the front and rear surfaces communicate with each other,
- a surface having an opening portion, wherein the opening portion comprises at least one spherical pore having a curved surface, and the curved surface comprises a true-spherical shape or a substantially true-spherical shape, and
- a surface roughness Ra of 30000 Å or less;
- and
- wherein the single layer porous film is laminated on the support such that the surface roughness Ra of 30000 Å or less adheres the single layer porous film to the support.
A battery comprising a separator,
- wherein the separator comprises a single layer porous film and an electrode,
- wherein the single layer porous film consists of:
- a film selected from the group consisting of a polyvinylidene fluoride film, a polyethersulfone film, a polyimide film and a polyamide-imide film,
- a front surface and a rear surface, wherein the front and rear surfaces communicate with each other,
- a surface having an opening portion, wherein the opening portion comprises at least one spherical pore having a curved surface, and the curved surface comprises a true-spherical shape or a substantially true-spherical shape, and
- a surface roughness Ra of 30000 A or less;
- and
- wherein the single layer porous film is laminated on the electrode such that the surface roughness Ra of 30000 A or less adheres the single layer porous film to the electrode.
Dependencies are inferred from the claim text.