| 摘要 |
PROBLEM TO BE SOLVED: To provide polyester film wherein dimensional stability is excellent and high electrical characteristics and thermal resistance can be obtained, by making the shrinkage stress in a longitudinal direction of the film satisfy specified formulas, and specifying the thickness of the whole film. SOLUTION: A coating layer is arranged on at least one side film surface, in order to increase adherence to vapor deposited metal formed as an electrode when a film is used as capacitor dielectrics. In the obtained film, the shrinkage stress in the longitudinal direction of the film simultaneously satisfies formulas 1, 2 (S150 is a shrinkage stress value per unit sectional area of the film at 150 deg.C, Smax is a shrinkage stress value in a temperature range of 150 deg.C up to the melting point of the film). The whole thickness of the film is in a range of 0.5-12μm. The dimensional change ratio in the longitudinal direction of the film which is measured with a TMA is set to be -2-2%. |
