BIAXIALLY ORIENTED POLYESTER FILM FOR CAPACITOR

摘要

PROBLEM TO BE SOLVED: To provide a biaxially oriented polyester film which keeps workability high enough for easy process, is capable of improving a capacitor in electrical properties, and suitable for a capacitor dielectric substance even after it is kept in a roll for a long term. SOLUTION: A capacitor biaxially oriented polyester film is 2.5μm or below in thickness in a weighing method and has projections which are located on its surface and 0.05 to 0.20μm in average height. The survival rate of quaternary or more projection height is 50% or above on the polyester film.