| 摘要 |
<p>PURPOSE: To prepare polypropylene mono film which is free from adhesion and corrosion resistant during processing of the film and has small fall in capacity by substantially eliminating microfibers and sinking from the smooth surface, where the two surfaces of the film have different roughness from each other. CONSTITUTION: In a biaxially stretched polypropylene mono film 1 made of pure polypropylene with an ash content less than 50 ppm, the film 1 has different roughness between the two surfaces 2, 3, and the average roughness of a smoother surface 3 is less than 0.25μm, the average roughness of a coarser surface 2 is made at least 0.25μm higher than the smoother surface. The smoother surface 3 is coated with a metal layer of 20-50 nm thickness. With the film 1 thickness of 8μm and the metal layer thickness of 25 nm, when 50 Hz AC 500 V is applied to a capacitor made of the film 1 for 2000 hours at 85 deg.C, the decrease in the capacity of the capacitor after it is -5% at maximum.</p> |
