Flame resistant silicone rubber compositions and methods
AssigneeGeneral Electric Company
InventorWilliam J. Bobear
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Abstract
The present invention provides curable organopolysiloxane compositions having improved flame retardant properties, comprising, (1) an organopolysiloxane gum convertible to the cured, solid, elastic state and consisting essentially of silicon atoms, oxygen atoms and organic groups selected from the class consisting of methyl radicals, aromatic radicals selected from the class consisting of aryl and halogenated aryl radicals, vinyl radicals, lower alkyl radicals, lower cyanoalkyl radicals and lower haloalkyl radicals, (2) a finely divided inorganic filler, (3) a platinum compound or platinum and (4) and various effective amounts of hydrated alumina, fumed titanium dioxide, and magnesium oxide.
Claims16
A composition curable to a silicone rubber exhibiting improved flame retardancy and tear strength comprising:
- (A) 100 parts by weight of a base compound comprising a polydiorganosiloxane gum or blend of polydiorganosiloxane gums having a viscosity of 1,000,000 to 200,000,000 centipoise at 25.degree. C., and having an average unit formula of R.sub.a SIO.sub.(4-a)/2, wherein R is a monovalent substituted or unsubstituted hydrocarbon radical selected from the class consisting of methyl, vinyl and phenyl radicals, a is approximately, 1.98 to 2.05, and wherein approximately, 0 to 5.0 mole percent of the total organic groups are vinyl radicals;
- (B) 0.01 to 250 ppm platinum;
- (C) 1.0 to 20 parts by weight hydrated alumina, and (D) 0.001 to 2.0 parts by weight magnesium oxide.
A process for producing a composition curable to a silicone rubber exhibiting improved flame retardancy and tear strength comprising the steps of compounding (A) 100 parts by weight of a base compound comprising a polydiorganosiloxane gum or blend of polydiorganosiloxane gum having a viscosity of 1,000,000 to 200,000,000 centipoise at 25.degree. C. and having an average unit formula of R.sub.a SiO.sub.(4-a)/2, wherein R is a monovalent substituted or unsubstituted hydrocarbon radical selected from the class consisting of methyl, vinyl and phenyl radicals, a is approximately 1.982 to 2.05 and wherein there is 0 to 5.0 percent vinyl radicals incorporated therein;
- (B) 0.01 to 250 ppm platinum;
- (C) 1.0 to 20 parts by weight hydrated alumina;
- and (D) 0.001 to 2.0 parts by weight mangesium oxide.
Dependencies are inferred from the claim text.