Microporous polyethylene film and method of producing the same

摘要

Disclosed is a microporous polyethylene film for a battery separator and a method of producing the same. The microporous polyethylene film comprises a resin mixture, which includes 100 parts by weight of composition containing 20-50 wt % polyethylene with a weight average molecular weight of 5x10⁴-3x10⁵ (component I) and 80-50 wt % diluent (component II), 0.1-2 parts by weight of peroxide (component III), and 0.05-0.5 parts by weight of anti-oxidant (component IV). The microporous polyethylene film has a puncture strength of 0.22 N/mum or more and a gas permeability (Darcy's permeability constant) of 1.3 Darcy or more. The present invention increases production efficiency of the microporous film, and improves performances and stability of the battery when the microporous polyethylene film is used in a battery separator.