Microporous composite film with high thermostable organic/inorganic coating layer

摘要

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 (CCSp) and permeability of a microporous polyolefin film (Sp) is 1.1≦CCSp/Sp≦3.5; and a permeability of the microporous composite film is 450 sec or less.

主权项

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 (CCSp) and permeability of the microporous polyolefin film (Sp) is 1.1≦CCSp/Sp≦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 (Sps1) before the formation of the coating layer and an average pore diameter of the microporous polyolefin film (Sps2) measured after removing the coating layer from the microporous composite film is 1.01≦Sps1/Sps2≦1.5.