| abstract |
In the present invention, a separator having a polyethylene microporous membrane and a heat resistant porous layer has a first object of providing a separator having sufficient shutdown function and heat resistance, which can be thinned and also improves slippery problems. . 1st this invention is a separator for non-aqueous secondary batteries provided with the microporous membrane which mainly consists of polyethylene, and the heat resistant porous layer which mainly consists of the heat resistant polymer formed in the at least one surface of this microporous membrane, (1) The said microporous membrane The Gurley value per unit thickness of is 25-35 seconds / 100 Pa.micrometer, (2) The said heat resistant porous layer contains the inorganic fine particles of 0.1-1.0 micrometer of average particle diameters, (3) The said heat resistant polymer and The volume of the inorganic fine particles is 40 to 80% with respect to the total volume of the inorganic fine particles, and (4) the total thickness of the heat resistant porous layer is 3 to 12 µm. |