Inhibitor for platinum catalyzed silicone rubber compositions

Claim 2

A platinum catalyzed silicone rubber composition with an improved work life comprising (a) 100 parts by weight of a vinyl-containing base linear polysiloxane of the formula, R.sub.a SiO.sub.4-a/2 and blends of such polysiloxanes, where R is selected from the class consisting of alkyl radicals of 1 to 8 carbon atoms, vinyl radicals, phenyl radicals, fluoroalkyl radicals of 3 to 10 carbon atoms and mixtures thereof, where the vinyl radical unsaturation in said polymer is at least 0.005 mole percent, a varies from 1.98 to 2.01, (b) at least 0.1 parts per million of platinum, (c) from 1 to 50 parts by weight of a hydrogen-containing polysiloxane, and (d) at least 0.007 parts by weight of an inhibitor compound having at least one radical of the formula, -- C -- O -- O -- H, per 100 parts of said vinyl-containing polymer.

Claim 3

The composition of claim 1 wherein the vinyl-containing base polysiloxane has the formula, ##STR7## and has a viscosity that varies from 1,000 to 300,000,000 centipoise at 25° C, where Vi is vinyl and R 1 is selected from the class consisting of vinyl, phenyl, alkyl radicals of 1 to 8 carbon atoms, fluoroalkyl radicals of 3 to 10 carbon atoms and mixtures thereof and where x varies from 330 to 11,000.

Claim 4

A composition of claim 1 wherein there is present a blend of vinyl-containing polysiloxanes comprised of a first polysiloxane of the formula of claim 2, with 1 to 50 parts by weight of a second vinyl-containing polysiloxane of the formula, ##STR8## where Vi is vinyl and R 2 is selected from the class consisting of alkyl radicals of 1 to 8 carbon atoms, phenyl, fluoroalkyl radicals of 3 to 10 carbon atoms and mixtures thereof, y varies from 1 to 4,000 and z varies from 1 to 4,000, which have a viscosity that varies from 1,000 to 1,000,000 centipoise at 25° C.

Claim 5

The composition of claim 3 wherein said first polysiloxane has a viscosity that varies from 1,000,000 to 200,000,000 centipoise at 25° C and said second polysiloxane has a viscosity that varies from 50,000 to 500,000 centipoise at 25° C.

Claim 6

The composition of claim 1 wherein the vinyl content of said vinyl-containing polysiloxane and blends of polysiloxane varies from 0.01 to 1.0 mole percent.

Claim 7

The composition of claim 1 wherein the concentration of said platinum catalyst varies from 1 to 50 parts per million

Claim 8

The compositon of claim 1 wherein the hydride compound is a hydride resin composed of, ##STR9## units and SiO 2 units where the ratio of R 3 to Si varies from 1.1 to 1.9 and R 3 is selected from the class consisting of alkyl radicals of 1 to 8 carbon atoms, phenyl radicals and fluoroalkyl radicals of 3 to 10 carbon atoms.

Claim 9

The composition of claim 1 wherein the hydride compound is a hydride resin composed of, ##STR10## units, SiO 2 units and (R 3 ) 2 SiO units where the R 3 to Si ratio may vary from 1.5 to 2.1 and R 3 is selected from the class consisting of alkyl radicals of 1 to 8 carbon atoms, phenyl radicals and fluoroalkyl radicals of 3 to 10 carbon atoms.

Claim 10

The composition of claim 1 wherein the hydride compound is a hydride containing polysiloxane of the formula, ##STR11## where R 4 is selected from the class consisting of alkyl radicals of 1 to 8 carbon atoms, phenyl, fluoroalkyl radicals of 3 to 10 carbon atoms, and hydrogen, v varies from 1 to 1000 andw varies from 0 to 200 and the viscosity of the polymer varies from 1 to 10,000 centipoise at 25° C.

Claim 11

The composition of claim 1 wherein there is present per 100 parts of (a) from 5 to 150 parts of a filler selected from the class consisting of titanium oxide, lithopone, zinc oxide, zirconium silicate, silica aerogel, iron oxide, diatomaceous earth, calcium carbonate, fumed silica, cyclicpolysiloxane treated silica, silazane treated silica, precipitated silica, glass fibers, magnesium oxide, chromic oxide, zirconium oxide, alpha quartz, calcined clay, asbestos, carbon, graphite, cork, cotton and synthetic fibers.

Claim 12

The composition of claim 1 wherein the concentration of the inhibitor compound varies from 0.01 to 10 parts.

Claim 13

The composition of claim 11 wherein the inhibitor compound is tertiary butyl hydroperoxide.

Claim 14

The composition of claim 11 wherein the inhibitor compound is methylethylketone peroxides.

Claim 15

The compositon of claim 11 wherein the inhibitor compound is cumene hydroperoxide.

Claim 16

The composition of claim 11 wherein the inhibitor compound is 1,1,3,3-tetramethylbutyl hydroperoxide.

Claim 17

The composition of claim 1 wherein the inhibitor compound is 2,5-dimethyl-2,5-dihydroperoxyhexane.

Claim 18

A process for forming a silicone composition which in the uncured state and at room temperature has a controlled work life comprising (A) mixing (a) 100 parts by weight of a vinyl-containing base linear polysiloxane of the formula, R.sub.a SiO.sub.4-a/2 and blends of such polysiloxanes where R is selected from the class consisting of alkyl radicals of 1 to 8 carbon atoms, vinyl radicals, phenyl radicals, fluoroalkyl radicals of 3 to 10 carbon atoms and mixtures thereof where the vinyl radical concentration in polysiloxanes is at least 0.005 mole percent, a varies from 1.98 to 2.01 with (b) at least 0.1 parts per million of platinum, and (c) from 1 to 50 parts by weight of a hydride compound which is a hydrogen-containing polysiloxane and (d) at least 0.007 parts by weight of an inhibitor compound having at least one radical -- C -- O -- O -- H per 100 parts of said vinyl-containing polymer and (b) allowing the composition to cure.

Claim 19

A process for forming a silicone composition which in the uncured state and at room temperature has a controlled work life comprising (A) mixing (a) 100 parts by weight of a vinyl-containing base linear polysiloxane of the formula, R.sub.a SiO.sub.4-a/2 and blends of such polysiloxanes where R is selected from the class consisting of alkyl radicals of 1 to 8 carbon atoms, vinyl radicals, phenyl radicals, fluoroalkyl radicals of 3 to 10 carbon atoms and mixtures thereof where the vinyl radical concentration in polysiloxanes is at least 0.005 mole percent, a varies from 1.98 to 2.01 with (b) at least 0.1 parts per million of platinum, and (c) from 1 to 50 parts by weight of a hydride compound which is a hydrogen-containing polysiloxane and (d) at least 0.007 parts by weight of an inhibitor compound having at least one radical -- C -- O -- O -- H per 100 parts of said vinyl-containing polymer and (b) allowing the composition to cure.

Claim 20

The process of claim 17 wherein the vinyl-containing per polysiloxane has the formula, ##STR12## and has a viscosity that varies from 1,000 to 300,000,000 centipoise at 25° C, where Vi is vinyl and R 1 is selected from the class consisting of vinyl, phenyl, alkyl radicals of 1 to 8 carbon atoms, fluoralkyl radicals of 3 to 10 carbon atoms and mixtures thereof and where x varies from 330 to 11,000.

Claim 21

A process wherein there is present a blend of vinyl-containing base polysiloxanes of a first polysiloxane of the formula of claim 18 with 1 to 50 parts by weight of a second vinyl-containing polysiloxane of the formula, ##STR13## where Vi is vinyl and R 2 is selected from the class consisting of alkyl radicals of 1 to 8 carbon atoms, phenyl, fluoroalkyl radicals of 3 to 10 carbon atoms and mixtures thereof, y varies from 1 to 4,000 and z varies from 1 4,000 which has a viscosity that varies from 1,000 to 1,000,000 centipoise at 25° C.

Claim 22

The process of claim 19 wherein said first polysiloxane has a viscosity that varies from 1,000,000 to 300,000,000 centipoise at 25° C and said second polysiloxane has a viscosity that varies from 50,000 to 500,000 centipoise at 25° C.

Claim 23

The process of claim 17 wherein the vnyl content of said vinyl-containing polysiloxane and blends of polysiloxane varies from 0.01 to 1.0 mole percent.

Claim 24

The process of claim 17 wherein the concentration of platinum catalyst varies from 1 to 50 parts per million.

Claim 25

The process of claim 17 wherein the hydride compound is a hydride resin composed of ##STR14## units and SiO 2 units where the ratio of R 3 is Si varies from 1.1 to 1.9 and R 3 is selected from the class consisting of alkyl radicals of 1 to 8 carbon aotms, phenyl radicals, and fluoroalkyl radicals of 3 to 10 carbon atoms.

Claim 26

The process of claim 17 wherein the hydride compound is a hydride resin composed of ##STR15## units, SiO 2 units and (R 3 ) 2 SiO units where the R 3 to Si ratio may vary from 1.5 to 2.1 and R 3 is selected from the class consisting of alkyl radicals of 1 to 8 carbon atoms, phenyl radicals and fluoroalkyl radicals of 3 to 10 carbon atoms.

Claim 27

The process of claim 17 wherein the hydride compound is a hydride containing polysiloxane of the formula, ##STR16## where R 4 is selected from the class consisting of alkyl radicals of 1 to 8 carbon atoms, phenyl, fluoroalkyl radicals of 3 to 10 carbon atoms and hydrogen, v varies from 1 to 1000 and w varies from 0 to 200 and the viscosity of the polymer varies from 1 to 10,000 centipoise at 25° C.

Claim 28

The process of claim 17 wherein there is present per 100 parts of (a) from 5 to 150 parts of a filler selected from the class consisting of titanium oxide, lithopone, zinc oxide, zirconium silicate, silica aerogel, iron oxide, diatomaceous earth, calcium carbonate, fumed silica, cyclic polysiloxane treated silica, silazane treated silica, precipitated silica, glass fibers, magnesium oxide, chromic oxide, zirconium oxide, alpha quartz, calcined clay, asbestos, carbon, graphite, cork, cotton and synthetic fibers.

Claim 29

The process of claim 17 wherein the concentration of the inhibitor compound varies from 0.01 to 10 parts.

Claim 30

The process of claim 17 wherein said inhibitor compound is tertiary butyl hydroperoxide.

Claim 31

The process of claim 17 wherein said inhibitor compound is methylethyl ketone peroxides.

Claim 32

The process of claim 17 wherein said inhibitor compound is cumene hydroperoxide.

Claim 33

The process of claim 17 wherein said inhibitor compound is 1,1,3,3-tetramethylbutyl hydroperoxide.

Claim 34

The process of claim 17 wherein said inhibitor compound is 2,5-dimethyl-2,5-dihydroperoxyhexane.

Claim 35

The process of claim 17 wherein the composition is cured at room temperature.

Claim 36

The process of claim 17 wherein the compositon is cured at elevated temperatures.