Compositions suitable for coating the surface of electrical high-voltage insulators

Abstract

Compositions for coating the surface of electrical high-voltage insulators, which are stable on storage in the absence of water and can be crosslinked to form elastomers at room temperature when exposed to water comprising (I) a diorganopolysiloxane having terminal groups capable of condensation with (II) a silicon compound having at least three hydrolyzable groups directly bonded to silicon per molecule; (III) optionally, an organic, nonreactive solvent; and (IV) an additive which is obtained by blending (A) 60 to 80 percent by weight of a diorganopolysiloxane containing 75 to 85 mol percent of dimethylsiloxane units and 15 to 25 mol percent of vinylmethylsiloxane units; (B) 20 to 35 percent by weight of titanium dioxide or zirconium dioxide; (C) 0.05 to 0.25 percent by weight of platinum, calculated as the element, in the form of a platinum compound or a platinum complex; and (D) 1 to 5 percent by weight of an organosilicon compound having a basic nitrogen bonded to silicon via carbon, in which the sum of the percentages of (A) to (D) is equal to 100 percent by weight and the percentages by weight of (A) to (D) are based on the total weight of additive (IV).

Dependencies are inferred from the claim text.