Curable organopolysiloxane compositions

Claim 2

An organopolysiloxane composition which forms an elastomer at an elevated temperature comprising: (a) An organopolysiloxane having an average of at least two hydroxyl groups per molecule; (b) an organosilicon compound containing aliphatic unsaturation and having an average of at least two hydrolyzable groups per molecule, said hydrolyzable groups are linked to a silicon atom of the organosilicon compound and are selected from the group consisting of acyloxy groups, aminoxy groups, amine groups, acylamine groups, oxime groups, mixtures and partial hydrolyzates thereof having 2 to 10 silicon atoms per molecule; (c) an organohydrogenpolysiloxane having an average of at least one silicon-bonded hydrogen atom per molecule; (d) a platinum catalyst; and (e) from 0 to 8 percent by weight based on the weight of the organopolysiloxane of a condensation catalyst

Claim 3

The composition of claim 1, wherein the condensation catalyst is present in the composition in an amount of at least 1 percent by weight based on the weight of the organopolysiloxane.

Claim 4

The composition of claim 1, wherein the composition contains a filler.

Claim 5

The composition of claim 1, wherein the organosilicon compound is selected from the group consisting of a silane of the formula R'.sub.a SiZ.sub.4-a where R' is a monovalent hydrocarbon radical having aliphatic unsaturation, Z is a hydrolyzable group selected from the group consisting of acyloxy groups, aminoxy groups, amine groups, acylamine groups, oxime groups, mixtures and partial hydrolyzates thereof having from 2 to 10 silicon atoms per molecule and a is 1 or 2.

Claim 6

The composition of claim 4, wherein Z is a mixture of hydrolyzable groups.

Claim 7

The composition of claim 4, wherein a is 2.

Claim 8

The composition of claim 4, wherein Z is an acyloxy group.

Claim 9

The composition of claim 4, wherein Z is an aminoxy group.

Claim 10

The composition of claim 4, wherein Z is an amine group.

Claim 11

The composition of claim 4, wherein Z is an acylamine group.

Claim 12

The composition of claim 4, wherein Z is an oxime group.

Claim 13

The composition of claim 1, wherein the organopolysiloxane is a hydroxyl-terminated organopolysiloxane.

Claim 14

The composition of claim 12, wherein the hydroxyl-terminated organopolysiloxane is represented by the formula HO--SiR.sub.2 (OSiR.sub.2).sub.m OSiR.sub.2 OH where R is selected from the group consisting of monovalent hdyrocarbon radicals and substituted monovalent hydrocarbon radicals having from 1 to 18 carbon atoms and m is a number such that the viscosity is from 50 to 500,000 mPa.s at 25° C.

Claim 15

The composition of claim 1, wherein the organohydrogenpolysiloxane is represented by the formula ##STR9## where R is selected from the group consisting of a monovalent hydrocarbon radical and a substituted monovalent hydrocarbon radical, b has a value of from 0 to 2.5; c has a value of from 0.0005 to 2.0 and the sum of b+c is equal to from 1.0 to 3.

Claim 16

The composition of claim 1, wherein the organohydrogenpolysiloxane is a copolymer having at least one siloxane unit of the formula ##STR10## where R is selected from the group consisting of a monovalent hydrocarbon radical and a substituted monovalent hydrocarbon radical, d has a value of 0, 1 or 2, e has a value of 1 or 2 and the sum of d+e is 1, 2 or 3 and the remaining siloxane units are represented by the formula ##STR11## where R is selected from the group consisting of a monovalent hydrocarbon radical and a substituted monovalent hydrocarbon radical and f has a value of 0, 1, 2 or 3.

Claim 17

The composition of claim 1, wherein the organohydrogenpolysiloxane has a viscosity of from 10 to 500,000 mPa.s at 25° C.

Claim 18

The composition of claim 1, wherein the organosilicon compound contains at least one vinyl group.

Claim 19

The composition of claim 1, wherein the organohydrogenpolysiloxane is present in an amount of from 1 to 15 percent by weight based on the weight of the hydroxyl-containing organopolysiloxane.

Claim 20

The composition of claim 1, wherein the hydroxyl-containing organopolysiloxane contains at least one alkenyl group per molecule and the organohydrogenpolysiloxane is present in an amount such that from 0.005 to 20 silicon-bonded hydrogen groups are present per alkenyl group.

Claim 21

The composition of claim 3, wherein the filler is a reinforcing filler.

Claim 22

The composition of claim 1, wherein the platinum catalyst is present in an amount of from one platinum atom per 1000 to one platinum atom per 100,000 parts of hydroxyl-containing organopolysiloxane.

Claim 23

An organopolysiloxane elastomer which is obtained by heating the composition of claim 1 to an elevated temperature.

Claim 24

The cured composition of claim 1.

Claim 25

The cured composition of claim 2.

Claim 26

The cured composition of claim 3.

Claim 27

A process for preparing the composition of claim 1, which comprises (1) mixing under anhydrous conditions, a hydroxyl-containing organopolysiloxane having an average of at least two hydroxyl groups per molecule with an organosilicon compound containing aliphatic unsaturation and having at least two hydrolyzable groups per molecule, in which the hydrolyzable groups are linked to the silicon atom of the organosilicon compound and are selected from the group consisting of acyloxy groups, aminoxy groups, amine groups, acylamine groups, oxime groups, mixtures and partial hydrolyzates thereof having from 2 to 10 silicon atoms per molecule, (2) adding an organohydrogenpolysiloxane, a platinum catalyst and from 0 to 8 percent by weight based on the weight of the organopolysiloxane of a condensation catalyst to the resultant mixture and then (3) heating the composition to an elevated temperature.

Claim 28

The process of claim 26, wherein the composition contains at least 1 percent by weight based on the weight of the organopolysiloxane of a condensation catalyst.

Claim 29

A two-package system which comprises one-package containing: (a) an organopolysiloxane having an average of at least two hydroxyl groups per molecule; (b) an organosilicon compound having an average of at least one alkenyl group per molecule and at least two hydrolyzable groups per molecule, said hydrolyzable groups are selected from the group consisting of aclyoxy groups, aminoxy groups, amine groups, acylamine gropps, oxime groups, mixtures and partial hydrolyzates thereof having from 2 to 10 silicon atoms per molecule; (c) a platinum catalyst; and a second package containing (d) an organohydrogenpolysiloxane having an average of at least one silicon-bonded hydrogen atom per molecule. I

Claim 30

A two-package system which comprises one-package containing: (a) an organopolysiloxane having an average of at least two hydroxyl groups per molecule; (b) an organosilicon compound having an average of at least one alkenyl group per molecule and at least two hydrolyzable groups per molecule, said hydrolyzable groups are selected from the group consisting of aclyoxy groups, aminoxy groups, amine groups, acylamine gropps, oxime groups, mixtures and partial hydrolyzates thereof having from 2 to 10 silicon atoms per molecule; (c) a platinum catalyst; and a second package containing (d) an organohydrogenpolysiloxane having an average of at least one silicon-bonded hydrogen atom per molecule. I