Patent ID: 7531592

Claim:
A composition for enhancing the arc-tracking and arc-erosion resistance properties of an article, comprising: a) a suspension containing (i) a polydimethylsiloxane oil terminated at each end of the chains by a (CH 3 ) 2 ViSiO 0.5 unit, where Vi is a vinyl group, and (ii) pyrogenic silica; b) a polydimethylsiloxane oil terminated at each end of the chains by a (CH 3 ) 2 HSiO 0.5 unit; c) a poly(dimethyl)(hydromethyl)siloxane oil terminated at each end of the chains by a (CH 3 ) 2 HSiO 0.5 unit; d) a platinum complex; e) a cyclic methylvinylpolysiloxane tetramer; and f) FeO and Fe 2 O 3 ; wherein the composition contains an effective amount of d) and f) to enhance the arc-tracking and arc-erosion resistance properties of the article, the composition having an extinction time of no more than 8 s, as determined by UL 94V, wherein in said composition the ratio of the amount by weight of FeO to that of Fe 2 O 3 lies within the range of from 0.1:1 to 9:1, and wherein the ratio of the amount by weight of the platinum metal in d) to the amount by weight of f) is from about 1:3846 to about 1:7692.