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US 4,539,357 AGranted
Peroxide curing polysiloxane compositions having a high tear strength
AssigneeGeneral Electric Company
InventorWilliam J. Bobear
Life of this patent
Estimating the term…
Abstract
The present invention relates to a silicon composition that cures to a silicone elastomer having a tear strength of abouve 100 p.i. comprising a blend of vinyl-containing gums, a silica reinforcing filler, a hydride cross-linking agent, and a peroxide curing catalyst.
Claims66
A polysiloxane composition curable to a silicone elastomer comprising:
- (A) 60-95 parts by weight of a vinyl-terminated linear diorganopolysiloxane gum having a viscosity in the range of 1.times.10.sup.6 to 20.times.10.sup.7 centipoise at 25.degree. C. and having a vinyl concentration in the range of 0.005 to 0.1 mole percent vinyl and where the organo groups are monovalent hydrocarbon radicals;
- (B) 5.0 to 40.0 parts by weight of a vinyl-containing diorganopolysiloxane gum having a viscosity in the range of 20.times.10.sup.6 to 100.times.10.sup.6 centipoise at 25.degree. C. and having a vinyl concentration in the range of 0.5 to 15.0 mole percent, wherein the organo groups are monovalent hydrocarbon radicals and the sum of (A) and (B) equals 100 parts by weight;
- (C) 10 to 300 parts by weight of filler, at least part of which is a reinforcing silica filler;
- (D) 0.1 to 25 parts by weight of hydride-containing polysiloxane having a hydride content ranging from 0.05 to 5.0 percent by weight and having a viscosity ranging from 10 to 1000 centipoise at 25.degree. C.;
- and
- (E) an effective amount of an organic peroxide free radical initiator curing agent.
3 more elements
A process for making a polysiloxane composition that is curable to a silicone elastomer comprising mixing:
- (A) 60-95 parts by weight of a vinyl-terminaed linear diorganopolysiloxane gum having a viscosity in the range of 1.times.10.sup.6 to 20.times.10.sup.7 centipoise at 25.degree. C. and having a vinyl concentration in the range of 0.005 to 0.1 mole percent vinyl and where the organo groups are monovalent hydrocarbon radicals;
- (B) 5.0 to 40.0 parts by weight of a vinyl-containing diorganopolysiloxane gum having a viscosity in the range of 20.times.10.sup.6 to 100.times.10.sup.6 centipoise at 25.degree. C. and having a vinyl concentration in the range of 0.5 to 15.0 mole percent, wherein the organo groups are monovalent hydrocarbon radicals and the sum of (A) and (B) equals 100 parts by weight;
- (C) 10 to 300 parts by weight of filler, at least part of which is a reinforcing silica filler;
- (D) 0.1 to 25 parts by weight of a hydride-containing polysiloxane having a hydride content ranging from 0.05 to 5.0 percent by weight and having a viscosity ranging from 10 to 1000 centipoise at 25.degree. C.;
- and
- (E) an effective amount of an organic peroxide free radical initiator curing agent.
3 more elements
A cured silicone elastomeric article formed by curing a mixture comprising:
- (A) 60 to 95 parts by weight of a vinyl-terminated linear diorganopolysiloxane gum having a viscosity in the range of 1.times.10.sup.6 to 20.times.10.sup.7 centipoise at 25.degree. C. and having a vinyl concentration in the range of 0.005 to 0.1 mole percent vinyl and where the organo groups are monovalent hydrocarbon radicals;
- (B) 5.0 to 40.0 parts by weight of a vinyl-containing diorganopolysiloxane gum having a viscosity in the range of 20.times.10.sup.6 to 100.times.10.sup.6 centipoise at 25.degree. C. and having a vinyl concentration in the range of 0.5 to 15.0 mole percent, wherein the organo groups are monovalent hydrocarbon radicals and the sum of (A) and (B) equals 100 parts by weight;
- (C) 10 to 300 parts by weight of filler, at least part of which is a reinforcing silica filler;
- (D) 0.1 to 25 parts by weight of hydride containing polysiloxane having a hydride content ranging from 0.05 to 5.0 percent by weight an having a viscosity ranging from 10 to 1000 centipoise at 25.degree. C.;
- and
- (E) an effective amount of an organic peroxide free radical initiator curing agent.
3 more elements
A method of making an elastomeric silicone article comprising:
- (i) mixing:
- (A) 60-95 parts by weight of a vinyl-terminated linear diorganopolysiloxane gum having a viscosity in the range of 1.times.10.sup.6 to 20.times.10.sup.7 centipoise at 25.degree. C. and having a vinyl concentration in the range of 0.005 to 0.1 mole percent, and where the organo groups are monovalent hydrocarbon radicals;
- (B) 5.0 to 40.0 parts by weight of a vinyl-containing diorganopolysiloxane gum having a viscosity in the range of 20.times.10.sup.6 to 100.times.10.sup.6 centipoise at 25.degree. C. and having a vinyl content in the range of 0.5 to 15.0 mole percent, wherein the organo groups are monovalent hydrocarbon radicals and the sum of (A) and (B) equals 100 parts by weight;
- (C) 10 to 300 parts by weight of a filler, at least part of which is a reinforcing silica filler;
- (D) 0.1 to 25 parts by weight of a hydride-containing polysiloxane having a hydride content ranging from 0.05 to 5.0 percent by weight and having an organic peroxide viscosity ranging from 10 to 1000 centipoise at 25.degree. C.;
- and
- (E) an effective amount of a free radical initiator curing agent;
- (ii) forming the mixture of step (i) into the desired shape;
- and
- (iii) heating the shaped composition at an elevated temperature in order to effect curing of the composition.
7 more elements
Dependencies are inferred from the claim text.