Silicone elastomers with good adhesion

Claim 2

A composition comprising the product obtained by mixing (A) a silanol-terminated polydiorganosiloxane, (B) a crosslinking agent for (A) which is a silicon compound having in the molecule at least three silicon-bonded groups selected from alkoxy and alkoxyalkoxy groups having less than 6 carbon atoms, (C) a metal or organometal salt of a carboxylic acid, (D) a silane of the general formula wherein R represents a hydrogen atom, an alkyl group having from 1 to 4 inclusive carbon atoms or an aliphatic hydrocarbon group attached to the nitrogen atom through a carbon to nitrogen bond and containing at least one amino group, R' represents an alkylene group having from 3 to 6 inclusive carbon atoms, X represents a monovalent hydrocarbon group having from 1 to 6 inclusive carbon atoms, Y represents an alkyl or alkoxyalkyl group having less than 6 carbon atoms and a has a value of 0 or 1, and (E) a silane of the general formula in which Z represents an organic group composed of carbon, hydrogen and oxygen having therein at least one group of the formula L represents an alkyi group having from 1 to 4 inclusive carbon atoms, or a phenyl group, M represents an alkyl or an alkoxyalkyl group having less than 6 carbon atoms and b has a value of 0 or 1, (D) and (E) being employed in a ratio of from 0.1 to 3 moles of (D) per mole of (E).

Claim 3

A composition as claimed in Claim 1 wherein the crosslinking agent (B) is a silane having 3 or 4 alkoxy groups attached to the silicon atom or is a partial hydrolysis and condensation product of such a silane.

Claim 4

A composition as claimed in Claim 1 or Claim 2 wherein (C) is a tin or organotin salt of a carboxylic acid.

Claim 5

A composition as claimed in any one of the preceding claims wherein (D) is a silane of the general formula or wherein R' represents an alkylene group having 3 or 4 carbon atoms and each Y represents methyl, ethyl or methoxyethyl.

Claim 6

A composition as claimed in any one of the preceding claims wherein the silane (E) has the general formula wherein M is methyl or ethyl.

Claim 7

A composition as claimed in any one of the preceding claims wherein the molar ratio of the amino silane (D) to the epoxy silane (E) is in the range from 0.4:1 to 0.7:1.

Claim 8

A composition as claimed in any one of the preceding claims wherein (D) and (E) are employed in a total weight of from 1.5 to 4.5 percent by weight based on the weight of (A).

Claim 9

A composition as claimed in any one of the preceding claims wherein (D) and (E) have been mixed together prior to mixing with the remaining components of the composition.

Claim 10

A process for the preparation of an elastomer which comprises mixing (A) a silanol-terminated polydiorganosiloxane, (B) a crosslinking agent for (A) which is a silicon compound having in the molecule at least three silicon-bonded groups selected from alkoxy and alkoxyalkoxy groups having less than 6 carbon atoms, (C) a metal or organometal salt of a carboxylic acid, (D) a silane of the general formula wherein R represents a hydrogen atom, an alkyl group having from 1 to 4 inclusive carbon atoms or an aliphatic hydrocarbon group attached to the nitrogen atom through a carbon to nitrogen bond and containing at least one amino group, R' represents an alkylene group having from 3 to 6 inclusive carbon atoms, X represents a monovalent hydrocarbon group having from 1 to 6 inclusive carbon atoms, Y represents an alkyl or alkoxyalkyl group having less than 6 carbon atoms and a has a value of 0 or 1, and (E) a silane of the general formula in which Z represents an organic group composed of carbon, hydrogen and oxygen having therein at least one group of the formula L represents an alkyl group having from 1 to 4 inclusive carbon atoms, or a phenyl group, M represents an alkyl or an alkoxyalkyl group having less than 6 carbon atoms and b has a value of 0 or 1, (D) and (E) being employed in a ratio of from 0.1 to 3 moles of (D) per mole of (E), and thereafter curing the composition.

Claim 11

A process for the preparation of an elastomer which comprises mixing (A) a silanol-terminated polydiorganosiloxane, (B) a crosslinking agent for (A) which is a silicon compound having in the molecule at least three silicon-bonded groups selected from alkoxy and alkoxyalkoxy groups having less than 6 carbon atoms, (C) a metal or organometal salt of a carboxylic acid, (D) a silane of the general formula wherein R represents a hydrogen atom, an alkyl group having from 1 to 4 inclusive carbon atoms or an aliphatic hydrocarbon group attached to the nitrogen atom through a carbon to nitrogen bond and containing at least one amino group, R' represents an alkylene group having from 3 to 6 inclusive carbon atoms, X represents a monovalent hydrocarbon group having from 1 to 6 inclusive carbon atoms, Y represents an alkyl or alkoxyalkyl group having less than 6 carbon atoms and a has a value of 0 or 1, and (E) a silane of the general formula in which Z represents an organic group composed of carbon, hydrogen and oxygen having therein at least one group of the formula L represents an alkyl group having from 1 to 4 inclusive carbon atoms, or a phenyl group, M represents an alkyl or an alkoxyalkyl group having less than 6 carbon atoms and b has a value of 0 or 1, (D) and (E) being employed in a ratio of from 0.1 to 3 moles of (D) per mole of (E), and thereafter curing the composition.

Claim 12

An article comprising a substrate having thereon the elastomeric product of the process of Claim 9.