| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a propylene-based resin microporous film which excels in the permeability of a lithium ion, can constitute a high-performance lithium ion battery, and also can prevent the short-circuit of a positive electrode and a negative electrode due to a dendrite. <P>SOLUTION: The propylene-based resin microporous film is obtained by subjecting a propylene-based resin film to monoaxial stretching to form micropores and the propylene-based resin has 25-60 wt.% components having a molecular weight of not greater than 50,000 and 19-30 wt.% components having a molecular weight of not smaller than 700,000, a weight average molecular weight of 350,000-500,000, and a relaxation time τ at an angular frequency ω of 1 rad/s obtained by the viscoelasticity measurement of 0.6-0.8 s, and the propylene-based resin microporous film further has a gas permeability of 100-400 s/100 mL, a porosity of 40-65%, and a maximum major diameter of the open end of a micropore of not greater than 500 nm. <P>COPYRIGHT: (C)2012,JPO&INPIT |
