Microporous composite film with high thermostable organic/inorganic coating layer

Patent metadata

Field	Value
Publication number	US-9564624-B2
Application number	US-201113702866-A
Country	US
Kind code	B2
Filing date	Jun 10, 2011
Priority date	Jun 10, 2010
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

Disclosed is a microporous composite film having a coating layer formed on at least one surface of a microporous polyolefin film, wherein the coating layer simultaneously includes a high thermostable polymer resin and inorganic particles. More specifically, the present invention relates to a microporous composite film in which an area shrinkage at 170° C. for 1 hr is 10% or less; a tensile modulus in each of a machine direction and a transverse direction at 130° C. is 0.5 MPa to 7.0 MPa; a ratio between permeability of a microporous composite film (CCS p ) and permeability of a microporous polyolefin film (S p ) is 1.1≦CCS p /S p ≦3.5; and a permeability of the microporous composite film is 450 sec or less.

First claim

The invention claimed is:

1. A microporous composite film having a coating layer with a thickness of 3 to 8 μm and a porosity of 25 to 60% formed on at least one surface of a microporous polyolefin film, the coating layer simultaneously including a high thermostable polymer resin having a melting temperature or glass transition temperature of 170° C. to 500° C. and inorganic particles having a porosity of 40 to 80%, wherein the microporous composite film has the following properties:
1) an area shrinkage (170° C., 1 hr) is 10% or less;
2) a tensile modulus in each of a machine direction and a transverse direction at 130° C. is 0.5 MPa to 7.0 MPa;
3) a ratio between permeability of the microporous composite film (CCS p ) and permeability of the microporous polyolefin film (S p ) is 1.1≦CCS p /S p ≦3.5;
4) a permeability of the microporous composite film is 450 sec or less; and
5) a ratio between an average pore diameter of the microporous polyolefin film (S ps1 ) before the formation of the coating layer and an average pore diameter of the microporous polyolefin film (S ps2 ) measured after removing the coating layer from the microporous composite film is 1.01≦S ps1 /S ps2 ≦1.5.

2. The microporous composite film of claim 1 , wherein the high thermostable polymer resin for forming the coating layer has a thermal distortion temperature of 170° C. or higher and the high thermostable polymer has an electrolyte impregnation rate at 80° C. of 1 to 20%.

3. The microporous composite film of claim 1 , wherein the inorganic particles for forming the coating layer have an average particle diameter of 0.3 to 1.5 μm and a surface area of 3 to 10 m 2 /g, and are selected from a group consisting of Al 2 O 2 , SiO 2 , BaTiO 3 , Al(OH) 3 and TiO 2 .

4. The microporous composite film of claim 1 , wherein the high thermostable polymer resin and the inorganic particles, for forming the coating layer, have a mass ratio of 30/70 to 5/95 and a solid content of 10 to 30%.

5. The microporous composite film of claim 1 , wherein the microporous polyolefin film has a thickness of 8 to 30 μm, a puncture strength of 0.15 N/μm or more, and a gas permeability of 40 to 250 sec, an average pore diameter of the surface area of the microporous polyolefin film is 25 to 75 nm.

Assignees

• Kim Yong Kyoung
• Rhee Jang Weon
• Joo Dong Jin
• Lee Je An
• Sung Jung Moon
• Sk Innovation Co Ltd

Inventors

• Kim Yong Kyoung
• Rhee Jang Weon
• Joo Dong Jin
• Lee Je An
• Sung Jung Moon

Classifications

• C08J7/0423 Primary

  with at least one layer of inorganic material and at least one layer of a composition containing a polymer binder · CPC title

• C08J7/0427

  with only one layer of a composition containing a polymer binder (with more layers C08J7/042) · CPC title

• C08J2323/02

  not modified by chemical after treatment · CPC title

• H01M10/052

  Li-accumulators · CPC title

• C08J9/365

  Coating · CPC title