{
  "$type": "site.standard.document",
  "description": "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. [0002] The propylene-based…",
  "path": "/patents/968594",
  "publishedAt": "2014-10-22T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "B29C48/0018",
    "SEKISUI CHEMICAL CO LTD [JP]"
  ],
  "textContent": "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. [0002] 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.",
  "title": "PROPYLENE-BASED RESIN MICROPOROUS FILM, BATTERY SEPARATOR, BATTERY AND METHOD FOR PRODUCING PROPYLENE-BASED RESIN MICROPOROUS FILM"
}