| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyester film for capacitor dielectric by which the deterioration of insulation resistance of capacitor can be reduced and the produc tion yield thereof be improved, by eliminating deterioration of insulation resis tance due to film, and a highly safe capacitor can be formed. SOLUTION: A film is made mainly of polyethylene terephthalate and is oriented biaxially. Its thermal deformation S120 at 120 deg.C in the lengthwise direction is represented by a formula, S120 =(L120 -L40 )/L40×100(%) (L120 : length of film sample at 120 deg.C; L40 : length of film sample at 40 deg.C). In this case, the thermal deformation S120 is 1 to 2. |
