Microporous high density polyethylene film and preparing method thereof

摘要

The present invention discloses a microporous high-density polyethylene film for a battery separator, and process for preparing the same. The microporous high-density polyethylene film according to the present invention comprises of high-density polyethylene with weight average molecular weight of 2x10⁵~4x10⁵, containing not more than 5 wt % of molecules with molecular weight of 1x10⁴ or less and not more than 5 wt % of molecules with molecular weight of 1x10⁶ or more, and has the properties of puncture strength of 0.22 N/mum or more, Darcy's permeability constant of 1.8x10^-5 Darcy or more, and shrinkage of 4% or less in machine and transverse direction, respectively. Particularly, the microporous high-density polyethylene film has excellent extrusion-compoundability and stretchability with high productivity and enhances performances and stability of the battery using the film.