Propylene-based resin microporous film, separator for battery, battery, and method for producing propylene-based resin microporous film

Patent metadata

Field	Value
Publication number	US-9748545-B2
Application number	US-201214363896-A
Country	US
Kind code	B2
Filing date	Dec 7, 2012
Priority date	Dec 13, 2011
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

The present invention provides a propylene-based resin microporous film which has excellent electrolyte solution retention property, and can provide a lithium ion battery in which a decrease in discharge capacity is highly reduced even after repeated charge and discharge. The propylene-based resin microporous film is a propylene-based resin microporous film having micropores, wherein a propylene-based resin having a weight average molecular weight of 250,000 to 500,000, a melting point of 160 to 170° C., and a pentad fraction of 96% or more is contained, the surface aperture ratio is 27 to 42%, the ratio of a surface aperture ratio to a porosity is 0.6 or less, and the degree of gas permeability is 50 to 400 s/100 mL.

First claim

The invention claimed is:

1. A propylene-based resin microporous film having micropores, comprising a propylene-based resin having a weight average molecular weight of 250,000 to 500,000, a melting point of 160 to 170° C., and a pentad fraction of 96% or more, and having a surface aperture ratio of 27 to 42%, a ratio of a surface aperture ratio to a porosity of 0.6 or less, a degree of gas permeability of 50 to 400 s/100 mL, and an electrolyte solution retention amount of 0.90 g/cm 3 to 1.5 g/cm 3 .

2. The propylene-based resin microporous film according to claim 1 , wherein aperture edges of the micropores have a longest diameter of 100 nm to 1 μm and an average longer diameter of 10 to 500 nm.

3. A separator for a battery, comprising the propylene-based resin microporous film according to claim 1 .

4. A battery, comprising the separator for a battery according to claim 3 .

5. A propylene-based resin microporous film having micropores, comprising a propylene-based resin having a weight average molecular weight of 250,000 to 500,000, a melting point of 160 to 170° C., a pentad fraction of 96% or more and a molecular weight distribution (weight average molecular weight/number average molecular weight) of 7.5 to 12.0, and having a surface aperture ratio of 27 to 42%, a ratio of a surface aperture ratio to a porosity of 0.6 or less, and a degree of gas permeability of 50 to 400 s/100 mL.

Assignees

• Sekisui Chemical Co Ltd

Inventors

• Kobaru Shotaro
• Sakurai Yuki

Classifications

• C08J5/18 Primary

  Manufacture of films or sheets · CPC title

• C08J2323/10

  Homopolymers or copolymers of propene · CPC title

• B29K2023/12

  PP, i.e. polypropylene · CPC title

• B29C48/0018

  combined with shaping by orienting, stretching or shrinking, e.g. film blowing (B29C48/0017 takes precedence) · CPC title

• B29L2031/3468

  Batteries, accumulators or fuel cells (battery cases B29L2031/7146) · CPC title