| 摘要 |
An insulated casing for a lithium secondary battery is provided to improve heat resistance and melt tension as compared with conventional homopolyethylene-based separators, to prevent an internal short upon overcharge or heat exposure, thereby imparting improved safety to a battery. An insulated casing(170) for a lithium secondary battery(100) is formed of a resin composition comprising 99.0-99.95 wt% of a polypropylene polymer having a long chain branched introduced thereto and showing a melt strength of at least 200 mN, and 0.05-1.0 wt% of an antioxidant. The polypropylene polymer is used preferably in an amount of 99.5-99.9 wt% and has a melt index of 0.1-20 g/10 min at 230 deg.C. |
