| 摘要 |
PROBLEM TO BE SOLVED: To provide a capacitor having excellent long-term stability by using a polypropylene film having specified ranges of mesopentad ratio, oxygen absorption induction time, and insulation resistance at a specified temperature. SOLUTION: The mesopentad ratio of a polypropylene film is 98% or higher, and the oxygen absorption induction time is 20 minutes or longer. If the insulation resistance IR1 at 20 deg.C is 1.5×10<5>ΩF or higher and the insulation resistance at 100 deg.C is expressed by IR2 , IR1 /IR2 is 70 or less. As a phenol antioxidant contained in this polypropylene film, tetrakis [methylene-3 (3,5-di-tertiary-butyl-4- hydroxyphenyl)propionate]methane, or 1,3,5 trimethyl-2,4,6-tris(3,5-di-tertiary- butyl-4-hydroxybenzyl)benzene is singly used, or these are used together at a rate of not less than 0.05 wt.% and not more than 0.40 wt.%. |
