US 4,072,635 A · Organosiloxane gels

Abstract

An organosiloxane gel is made by reacting (1) an organosiloxane having a viscosity of from 10 to 10,000 centistokes at 25.degree. C. and being a copolymer consisting essentially of units of the formula R.sub.2 ViSiO.sub.0.5, RViSiO, R.sub.2 SiO and MeR.sub.2 SiO.sub.0.5, where each R is individually selected from the group consisting of methyl and phenyl radicals, Vi represents a vinyl radical and Me represents a methyl radical, at least 0.50 molar percent of the units in said copolymer being R.sub.2 ViSiO.sub.0.5 units and RViSiO units where the terminal groups are at least 50 mole percent of R.sub.2 ViSiO.sub.0.5 units and may have as the rest of the total terminal units MeR.sub.2 SiO.sub.0.5 units, (2) a liquid hydrogen siloxane of the average general formula XRMeSIO(R.sub. 2 SiO).sub.n (RHSiO).sub.m SiMeRX, where each R is as above defined and X is selected from the group consisting of H and R and n and m have such average values that the viscosity of the hydrogen siloxane is no more than 10,000 centistokes at 25.degree. C. and m is at least 1, no more than 25 molar percent of the total R radicals present in (1) and (2) being phenyl and (3) a platinum or platinum compound catalyst in an amount sufficient to furnish about at least 0.1 part per million of platinum based upon the combined weights of (1) and (2); the proportions of (1) and (2) being such that prior to reaction there is an average of from 1.4 to 1.8 gram atoms of the silicon-bonded hydrogen atoms in (2) per gram molecular weight of (1) and there being at least one vinyl siloxy units in (1) for every silicon-bonded hydrogen atom in (2), the molecular weight of (1) being calculated by the equation: log visc.= 1.00+ 0.0123M.sup..5 where M is the molecular weight and "visc." is the viscosity of (1) in centistokes at 25.degree. C. The gel can be filled with glass microballoons to lower their specific gravity. The gel produced finds utility in collision pads in automobiles, shock absorbing bumpers, mattresses, snowmobile seats, padding and crash helmets and insulation which can be pumped into electrical conduits, among other things.

Claims18

Dependent claims

A reaction product silicone gel of a mixture comprising reacting (1) an organosiloxane having a viscosity of from 10 to 10,000 centistokes at 25.degree. C, and being a copolymer consisting essentially of units of the formula R.sub.2 ViSiO.sub.0.5, RViSiO, R.sub.2 SiO and MeR.sub.2 SiO.sub.0.5, where each R is individually selected from the group consisting of methyl and phenyl radicals and Vi represents a vinyl radical, at least 0.50 molar percent of the units in said copolymer being R.sub.2 ViSiO.sub.0.5 units and RViSiO units where the terminal groups are at least 50 mole percent ViR.sub.2 SiO.sub.0.5 units and may have as the rest of the total terminal units MeR.sub.2 SiO.sub.0.5 units, (2) a liquid hydrogen siloxane of the average general formula XRMeSiO(R.sub.2 SiO).sub.n (RHSiO).sub.m SiMeRX, where each R is as above defined and X is selected from the group consisting of H and R, no more than 25 molar percent of the total R radicals present in (1) and (2) being phenyl, and n and m have such average values that the viscosity of the hydrogen siloxane is no more than 10,000 centistokes at 25.degree. C and m is at least 1, in the presence of a platinum or platinum compound catalyst in an amount sufficient to furnish at least 0.1 part per million of platinum based upon the combined weights of (1) and (2);

the properties of (1) and (2) being such that prior to reaction there is an average of from 1.4 to 1.8 gram atoms of the silicon-bonded hydrogen atoms in (2) per gram molecular weight of (1) and there being at least one vinyl siloxy unit in (1) for every silicon-bonded hydrogen atom in (2), the molecular weight of (1) being calculated by the equation:
log visc. = 1.00 + 0.0123M.sup..5
where M is the molecular weight and "visc." is the viscosity of (1) in centistokes at 25.degree. C.

A process for forming a silicone gel comprising reacting (1) an organosiloxane having a viscosity of from 10 to 10,000 centistokes at 25.degree. C, and being a copolymer consisting essentially of units of the formula R.sub.2 ViSiO.sub.0.5, RViSiO, R.sub.2 SiO and MeR.sub.2 SiO.sub.0.5, where each R is individually selected from the group consisting of methyl and phenyl radicals and Vi represents a vinyl radical, at least 0.50 molar percent of the units in said copolymer being R.sub.2 ViSiO.sub.0.5 units and RViSiO units where the terminal groups are at least 50 mole percent ViR.sub.2 SiO.sub.0.5 units and may have as the rest of the total terminal units MeR.sub.2 SiO.sub.0.5 units, (2) a liquid hydrogen siloxane of the average general formula, XRMeSiO(R.sub.2 SiO).sub.n (RHSiO).sub.m SiMeRX, where each R is as above defined and X is selected from the group consisting of H and R, no more than 25 molar percent of the total R radicals present in (1) and (2) being phenyl, and n and m have such average values that the viscosity of the hydrogen siloxane is no more than 10,000 centistokes at 25.degree. C and m is at least 1, in the presence of a platinum or platinum compound catalyst in an amount sufficient to furnish at least 0.1 part per million of platinum based upon the combined weights of (1) and (2), the properties of (1) and (2) being such that prior to reaction there is an average of from 1.4 to 1.8 gram atoms of the silicon-bonded hydrogen atoms in (2) per gram molecular weight of (1) and there being at least one vinyl siloxy unit in (1) for every silicon-bonded hydrogen atom in (2), the molecular weight of (1) being calculated by the equation:

log visc. = 1.00 + 0.0123M.sup..5
where M is the molecular weight and "visc."is the viscosity of (1) in centistokes at 25.degree. C.

Dependencies are inferred from the claim text.

Organosiloxane gels

Life of this patent

Organosiloxane gels

Life of this patent

Abstract

Claims18