POLYPROPYLENE FILM FOR CONDENSER AND CONDENSER FORMED THEREFROM

摘要

PROBLEM TO BE SOLVED: To provide a film that can be produced in a usual manufacturing process and that reduces the occurrence of blocking when it is processed and handled and will give a little squeak in a condenser element into which it has been molded by specifying the number of protrusions having a specified protrusion diameter present on the film surface and subjecting both surfaces of the film to a corona discharge treatment. SOLUTION: The number of protrusions having a long diameter of not less than 5μm on at least one surface of the polypropylene film is from not less than 0.5/mm2 to not more than 20/mm2. The upper limit of the respective long diameter of the protrusions is not particularly restricted, but it is preferably not more than 20μm from the point of view of the running properties and blocking properties of the film. It is desirable that the film is subjected to a corona discharge treatment so that the film has a wet tensile strength of 36-47 mN/m on the surface which is provided with a metal layer and a wet tensile strength of 33-40 mN/m on the surface which is not provided with a metal layer. It is desirable that at least one surface of the film is provided with a deposited metal layer.