ON ONE SIDE METALLIZED BIAXIALLY STRETCHED POLYPROPYLENE FOIL TO BE USED AS ELECTROINSULATING FOIL

摘要

Disclosed is a biaxially stretched, composite polypropylene film suitable for use as an electrical insulating film, comprising a first layer comprising a first propylene polymer and having a maximum roughness height Rz of its exposed surface of about 0.5 mu m, and a second layer contiguous to the first layer comprising a second propylene polymer having a composition different from the first propylene polymer and having a roughness height Rz on its exposed surface ranging between about 0.2 mu m and 0.4 mu m, with the composite film having a modulus of elasticity of at least about 2000 N/mm2 in all directions of the plane of the film and a DC dielectric strength of at least about 650 V/ mu m. Also disclosed is a capacitor comprised of a plurality of these composite films having a metal surface layer and being laminated with one another.