Prime Polymer Co., Ltd.

Hiroki Shimizu

Satoshi Tamura

Jun Birukawa

An object of the present invention is to provide a film for a capacitor such that the film excels in high-temperature dielectric breakdown voltage (high-temperature BDV) and has blocking resistance, and bleeding-out of, for instance, a nucleating agent is suppressed even after long-term storage. The present invention pertains to a multilayer polypropylene film for a capacitor, the film including a base layer composed of a propylene polymer composition containing a propylene homopolymer (X) and 0.0001 to 0.05 mass % of a polymer-based α-crystal nucleating agent (C), and a front layer or a back layer composed of a propylene-based polymer (Y) on at least one surface of the base layer, wherein the base layer and the front layer or back layer are stretched.

Multilayer polypropylene film for capacitor

A polypropylene (F) for film condensers having the following requirements: (1) an MFR (JIS K 7210, 230&#xb0; C., 2.16 kg load) in the range of 1-10 (g/10 min), (2) an mmmm fraction that is at least 93%, (3) a &#x3c;2,1&#x3e;erythro position defect amount as measured usingC-NMR that is less than 0.1 mol %, (4) ash content obtained by complete combustion in atmosphere that is at most 50 ppm, (5) chlorine content as measured by ion chromatography that is at most 5 ppm; and (6) is obtained by including a propylene homopolymer for which Mw/Mn as measured via GPC is 6.5-12 and an &#x3b1;-crystal nucleating agent with a melting point of at most 290&#xb0; C.

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Ichihara, Japan

Hiroki Shimizu