Rubber compositions

Claim 2

In a rubber composition comprising a curable rubber, from 10 to 90 parts, per 100 parts of rubber, of finely divided reinforcing siliceous pigment and a coupling amount of a silane coupling agent, the improvement wherein a silane coupling composition of the silane coupling agent in combination with an alkoxysilane is admixed with said siliceous pigment, said alkoxysilane having the graphic formula: R"--Si--(OR').sub.3, wherein R' is selected from C 1 -C 10 alkyl or alkoxyalkyl containing from 2 to 10 carbon atoms, and R" is a C 1 -C 10 alkyl, and the silane coupling agent is chosen from the group consisting of: (a) organic silane compounds containing an internal active olefinic linkage, (b) bis(alkoxysilylalkyl)polysulfides, (c) haloalkylsilanes, and (d) silane compounds containing a vinyl functional group in the organofunctional portion of the compound, the weight ratio of the silane coupling agent to alkoxysilane being between 0.15:1 and 15:1.

Claim 3

The rubber composition of claim 1 wherein th alkoxysilane is methyltrimethoxysilane.

Claim 4

The rubber composition of claims 1 or 2 wherein the ratio of silane coupling agent to alkoxysilane is between 0.6:1 and 6:1.

Claim 5

The rubber composition of claims 1 or 2 wherein the silane coupling agent is selected from the group consisting of: (a) compounds represented by the designation A-B, wherein A is: ##STR6## wherein X is halogen or OR', M is hydrogen, C 1 -C 10 alkyl, or halosubstituted C 1 -C 10 alkyl, R' is C 1 -C 10 alkyl or alkoxyalkyl containing from 2 to 10 carbon atoms, and n is 1, 2 or 3, and B is norbornenyl, cyclopentenyl, 2-butenyl, 2-methyl-2-butenyl, 3-methyl-2-butenyl, 2,3-dimethyl-2-butenyl, 2-ethylidene norbornanyl, and dicyclopentadienyl; (b) compounds reprsented by the designation, Z--alk--S.sub.n' --alk--Z, wherein alk is a divalent hydrocarbon radical having from 1 to 18 carbon atoms, n' is a whole number of from 2 to 6, and Z is, ##STR7## wherein R 1 is a C 1 -C 4 alkyl or phenyl group, and R 2 is a C 1 -C 8 alkoxy, C 5 -C 8 cycloalkoxy or C 1 -C 8 alkylmercapto group; (c) compounds represented by the designation, X p --C m H 2m+1-p A, wherein A is as defined above, X is halogen, p is 1 or 2 and m is 1 to 5; and (d) compounds represented by the designation, R 1 -A, wherein A is as defined above and R 1 is a C 2 -C 8 alkenyl or an alkenylcarboxyalkyl having from 4 to 10 carbon atoms.

Claim 6

The rubber composition of claim 1 wherein the curable rubber is a sulfur-curable rubber.

Claim 7

The rubber composition of claim 1 wherein the silane coupling agent and alkoxysilane are added to the rubber composition admixed with a rubber process oil.

Claim 8

A vulcanizate prepared from the rubber composition of claims 1 or 2.

Claim 9

A vulcanizate prepared from the rubber composition of claim 4.

Claim 10

A vulcanizate prepared from the rubber composition of claim 6.

Claim 11

A substantially dry, free-flowing rubber compounding additive suitable for incorporation into a vulcanizable rubber composition comprising from about 25 to 75 weight percent of rubber reinforcing finely-divided siliceous pigment and from 75 to 25 weight percent of organic silane coupling composition, said silane coupling composition being applied as a combination of an alkoxysilane of the graphic formula, R"--Si--(OR').sub.3, wherein R' is selected from C 1 -C 10 alkyl or alkoxyalkyl containing from 2 to 10 carbon atoms and R" is a C 1 -C 10 alkyl, and an organic silane coupling agent selected from the groups: (a) organic silane compounds containing an internal active olefinic linkage, (b) bis(alkoxysilylalkyl)polysulfides, (c) haloalkylsilanes, and (d) silane compounds containing a vinyl functional group in the organofunctional portion of the compound, the weight ratio of the silane coupling agent to alkoxysilane being between 0.15:1 and 15:1.

Claim 12

A substantially dry, free-flowing rubber compounding additive suitable for incorporation into a vulcanizable rubber composition comprising from about 25 to 75 weight percent of rubber reinforcing finely-divided siliceous pigment and from 75 to 25 weight percent of organic silane coupling composition, said silane coupling composition being applied as a combination of an alkoxysilane of the graphic formula, R"--Si--(OR').sub.3, wherein R' is selected from C 1 -C 10 alkyl or alkoxyalkyl containing from 2 to 10 carbon atoms and R" is a C 1 -C 10 alkyl, and an organic silane coupling agent selected from the groups: (a) organic silane compounds containing an internal active olefinic linkage, (b) bis(alkoxysilylalkyl)polysulfides, (c) haloalkylsilanes, and (d) silane compounds containing a vinyl functional group in the organofunctional portion of the compound, the weight ratio of the silane coupling agent to alkoxysilane being between 0.15:1 and 15:1.

Claim 13

The rubber compounding additive of claim 10 wherein the alkoxysilane is methyltrimethoxysilane.

Claim 14

The rubber compounding additive of claims 10 or 11 wherein the silane coupling agent is selected from the group consisting of: (a) compounds represented by the designation A-B, wherein A is: ##STR8## wherein X is halogen or OR', M is hydrogen, C 1 -C 10 alkyl, or halosubstituted C 1 -C 10 alkyl, R' is C 1 -C 10 alkyl or alkoxyalkyl containing from 2 to 10 carbon atoms, and n is 1, 2 or 3, and B is norbornenyl, cyclohexenyl, cyclopentenyl, 2-butenyl, 2-methyl-2-butenyl, 3-methyl-2-butenyl, 2,3-dimethyl-2-butenyl, 2-ethylidene norbornanyl, and dicyclopentadienyl; (b) compounds represented by the designation, Z--alk--S.sub.n' --alk--Z, wherein alk is a divalent hydrocarbon radical having from 1 to 18 carbon atoms, n' is a whole number of from 2 to 6, and Z is, ##STR9## wherein R 1 is a C 1 -C 4 alkyl or phenyl group, and R 2 is a C 1 -C 8 alkoxy, C 5 -C 8 cycloalkoxy or C 1 -C 8 alkylmercapto group; (c) compounds represented by the designation, X p --C m H 2m+1-p A, wherein A is as defined above, X is halogen, p is 1 or 2, and m is 1 to 5; and (d) compounds represented by the designation, R 1 -A, wherein A is as defined above and R 1 is a C 2 -C 8 alkenyl or an alkenylcarboxyalkyl having from 4 to 10 carbon atoms.

Claim 15

The rubber compounding additive of claims 10 or 11 wherein the weight ratio of silane coupling agent to alkoxysilane is from about 0.6:1 to about 6:1.

Claim 16

The rubber compounding additive of claims 10 or 11 wherein the rubber process oil is also present and the weight ratio of silane coupling agent to alkoxysilane is about 1:1.

Claim 17

The rubber compounding additive of claim 12 wherein the weight ratio of silane coupling agent to alkoxysilane is from about 0.6:1 to about 6:1.

Claim 18

The rubber compounding additive of claim 12 wherein the rubber process oil is also present and the weight ratio of silane coupling agent to alkoxysilane is about 1:1.