Electrically conductive silicone rubber compositions
AssigneeToray Silicone Company, Ltd.
InventorsHideki Kobayashi, Mitsuo Hamada
Life of this patent
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Abstract
Cured electrically conductive silicone rubber products exhibiting bleed-out of a silicone oil at a controlled rate are prepared from compositions containing carbon black and a curable polyorganosiloxane wherein 90 mol % of the silicon-bonded hydrocarbon groups are methyl. The silicone oil is a liquid polyorganosiloxane containing at least 1 mol %, based on the total number of hydrocarbon radicals present in said silicone oil, of silicon-bonded halogenated hydrocarbon radicals and the silicone oil is incompatible with the cured silicone rubber product.
Claims14
A curable, electrically conductive silicone rubber composition comprising
- (A) 100 parts by weight of a polyorganosiloxane having a viscosity of at least 0.1 mm.sup.2 /s and an average unit formula R.sub.a SiO.sub.4-a/2, where R represents a monovalent hydrocarbon radical or a 2-cyanoethyl radical, a has a value of from 1.95 to 2.05, and at least 90 mol % of the R radicals are methyl;
- (B) 0 to 100 parts by weight of a finely divided silica filler;
- (C) 5 to 100 parts by weight of an electrically conductive carbon black;
- (D) 1 to 100 parts by weight of an incompatible polyorganosiloxane having a viscosity of from 0.01 to 10 mm.sup.2 /s at 25.degree. C. and an average unit formula
- R.sub.b.sup.1 R.sub.c.sup.2 SiO.sub.(4-b-c)/2,
- where R.sup.1 is selected from the same group as R, R.sup.2 represents a halogenated hydrocarbon radical, b is from 1 to 3 inclusive, c is from 0.001 to 1 inclusive, the sum of b and c is from 1.95 to 2.95 inclusive and where said incompatible polyorganosiloxane bleeds out at a controlled rate from the surface of said silicone rubber composition following curing of said composition;
- (E) 0.1 to 10 parts by weight of a curing agent for (A), said curing agent being selected from the group consisting of organoperoxides and combinations of a polyorganohydrogensiloxane, a polyorganosiloxane (A) containing alkenyl radicals and an amount of a platinum-containing catalyst sufficient to cure said composition.
Dependencies are inferred from the claim text.