Silicone rubber compositions for high-voltage electrical insulators and polymer insulators

摘要

A silicone rubber composition comprising (A) 100 parts by weight of an organopolysiloxane composition of the organic peroxide or addition curing type, (B) 1-100 parts by weight of finely divided silica, and (C) 30-500 parts by weight of aluminum hydroxide is suitable for use as a high- voltage electrical insulator. The aluminum hydroxide (C) has a water- soluble sodium ion content of up to 0.01% by weight and exhibits pH 6.5-8. 0 and an electrical conductivity of up to 50 &mgr;s/cm when measured as a 30 wt % water slurry and preferably has been treated to be hydrophobic. The composition cures into a silicone rubber having improved high-voltage electrical insulating properties even under rigorous conditions.