Layered porous film, and non-aqueous electrolyte secondary battery
A laminated porous film includes a porous base material layer containing polyolefin as a main component; a filler layer containing inorganic particles as a main component; and a resin layer containing resin particles as a main component, the resin particles showing an endothermic curve satisfying conditions (1) and (2) below, the endothermic curve being obtained by differential scanning calorimetry. Condition (1): a temperature at which DDSC is not less than 0.10 mW/min/mg is not less than 70° C. Condition (2): endothermic amount calculated from an area of the endothermic curve in a range of not less than 50° C. and not more than 70° C. is not less than −20.0 J/g.
1. A laminated porous film comprising:
a porous base material layer containing polyolefin as a main component;
a filler layer containing inorganic particles as a main component; and
a resin layer containing resin particles as a main component, the resin particles showing an endothermic curve satisfying conditions (1) and (2) below, the endothermic curve being obtained by differential scanning calorimetry:
Condition (1): a temperature at which DDSC is not less than 0.10 mW/min/mg is not less than 70° C.,
Condition (2): endothermic amount calculated from an area of the endothermic curve in a range of not less than 50° C. and not more than 70° C. is not less than −20.0 J/g.
2. The laminated porous film as set forth in claim 1 , wherein the resin particles are Fischer-Tropsch wax.
3. The laminated porous film as set forth in claim 1 , wherein:
the filler layer is provided on one surface of the porous base material layer; and
the resin layer is provided on the other surface of the porous base material layer.
4. The laminated porous film as set forth in claim 1 , wherein:
a ratio of a weight per unit area of the filler layer to a weight per unit area of the porous base material layer is 0.2 to 3.0; and
a ratio of a weight per unit area of the resin layer to a weight per unit area of the porous base material layer is 0.1 to 2.0.
5. The laminated porous film as set forth in claim 1 , wherein
the inorganic particles are at least one selected from the group consisting of alumina, boehmite, silica, and titania.
6. The porous film as set forth in claim 1 , wherein
the inorganic particles are α-alumina.
7. The laminated porous film as set forth in claim 1 , wherein
the filler layer contains an organic binder.
8. The laminated porous film as set forth in claim 7 , wherein
the organic binder is a water-soluble polymer.
9. The laminated porous film as set forth in claim 8 , wherein
the water-soluble polymer is at least one selected from the group consisting of carboxyalkyl cellulose, alkyl cellulose, and hydroxyalkyl cellulose.
10. The laminated porous film as set forth in claim 1 , wherein
the resin layer contains an organic binder.
11. The laminated porous film as set forth in claim 10 , wherein
the organic binder is a water-insoluble polymer.
12. The laminated porous film as set forth in claim 11 , wherein
the water-insoluble polymer is at least one selected from the group consisting of an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid ester copolymer, a fluorine-based rubber, and a styrene butadiene rubber.
13. A nonaqueous electrolyte secondary battery comprising:
a laminated porous film recited in claim 1 .