| 摘要 |
Disclosed is a microporous polyolefin multilayer film which can be used as a separator for a battery, and a preparing method thereof. The microporous polyolefin multilayer film is a trilayer microporous film which is prepared by a wetting method to have both surface layers containing polyethylene of 95 wt % or more having a melting temperature of 125° C. or more, and an intermediate layer containing polypropylene of 50 to 90 wt % having a melting temperature of 160° C. or more and polyethylene of 10 to 50 wt % having a melting temperature of 125° C. or more, wherein a thickness of the film is 9-50 μm, a puncture strength is 0.15 N/μm or more, a permeability is 1.5×10−5 Darcy or more, a multiplication of the puncture strength and the permeability is 0.4×10−5 Darcy·N/μm or more, a contraction rate in a traverse direction at a temperature of 150° C. for 1 hour is 15% or less, and a melt fracture temperature of 160° C.
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