| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a propylene-based resin microporous film which excels in lithium ion permeability, can be used to fabricate a high-performance lithium ion battery, and can prevent a short circuit between 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 uniaxial drawing to form micropores. The propylene-based resin has a weight average molecular weight of 250,000-500,000, a molecular weight distribution of 7.5-12.0, and a melting point of 160-170°C. The propylene-based resin film has a heat quantity of fusion obtained by differential scanning calorimetric analysis of ≥110 mJ/mg and a birefringence of ≥1.4×10<SP POS="POST">-2</SP>. <P>COPYRIGHT: (C)2013,JPO&INPIT |
