BOPP film with high AC breakdown strength

摘要

Polypropylene composition comprising a polypropylene and an α-nucleating agent, wherein the polypropylene composition has • a comonomer content of equal or below 1.0 wt.- %, •<2,1> erythro regiodefects of more than 0.1 mol.- %, and • at least 9.0 wt- % of a crystalline fraction crystallizing in the temperature range of above 160 to 170° C., wherein said fraction is determined by the stepwise isothermal segregation technique (SIST).

主权项

1. A capacitor comprising at least one layer comprising a capacitor film comprising a biaxially oriented polypropylene (BOPP) film comprising a polypropylene composition (PP-C), the polypropylene composition (PP-C) comprising:
(i) at least 70 wt. % of a polypropylene (PP) and (ii) 0.005 to 1.5 wt. % of an α-nucleating agent (N) based on the polypropylene composition (PP-C), wherein the polypropylene composition (PP-C) and/or the polypropylene (PP) has/have (a) a comonomer content of equal or below 1.0 wt. %, the comonomers are ethylene and/or at least one C4 to C20 α-olefin, and (b) <2,1> erythro regiodefects of more than 0.1 mol. % determined by 13C-spectroscopy, and wherein further (c) the polypropylene composition (PP-C) and/or the polypropylene (PP) has/have a pentad isotacticity of at least 98 mol. %, and/or (d) the polypropylene composition (PP-C) comprises at least 9.0 wt % of a crystalline fraction crystallizing in the temperature range of above 160 to 170° C., wherein said fraction is determined by the stepwise isothermal segregation technique (SIST), wherein the biaxially oriented (BOPP) film has an electrical breakdown strength EB63% derived from data measured according to IEC 60243 part 1 (1998) and evaluated according to IEC 60727, part 1 & 2 of at least 310 kV/mm obtained on a biaxially oriented direction of 5.0.