Polypropylene for film capacitor, polypropylene sheet for film capacitor, method for producing the same, and uses of the same

摘要

A polypropylene for a film capacitor or a polypropylene sheet for a film capacitor which exhibits excellent stretchability when stretched into a film and provides a film having high breakdown voltage and small thermal shrinkage ratio, and which is suitable for a polypropylene film for a film capacitor and a film capacitor comprising the film.;The polypropylene for a film capacitor of the present invention is obtained by irradiating a propylene homopolymer with a radiation with an absorbed dose of 0.1 to 500 kGy, the propylene homopolymer having (1) a melt flow rate (MFR) within a range of 1 to 10 g/10 min as determined at 230° C. under a load of 2.16 kg in accordance with ASTM D1238, (2) an isotactic pentad fraction (mmmm fraction) of not less than 94% as determined using 13C-NMR, (3) an ash amount of not more than 30 ppm as obtained by completely burning the propylene homopolymer in air, and (4) a chlorine amount of not more than 10 ppm as determined by ion chromatography.

主权项

1. A polypropylene for a film capacitor which is obtained by irradiating a propylene homopolymer with a radiation with an dose of 0.1 to 500 kGy. wherein the propylene homopolymer has:
(1) a melt flow rate (MFR) within a range of 1 to 10 g/10 min as determined at 230° C. under a load of 2.16 kg in accordance with ASTM D1238, (2) an isotactic pentad traction (mmmm fraction) of not less than 98% as determined using 13C-NMR, (3) an ash amount of not more than 20 ppm as obtained by completely burning the propylene homopolymer in air, (4) a chlorine amount of not more than 10 ppm as determined by ion chromatography, and (5) a melting point (Tm) of not lower than 166° C. as measured by differential scanning calorimetry (DSC).