Process for producing alkoxy-terminated polysiloxanes

Claim 2

A process for producing alkoxy-terminated polysiloxanes which can be used to produce RTV silicone rubber compositions, comprising, anhydrously reacting (1) a silanol or vinyl siloxane selected from a silanol-terminatad diorganopolysiloxane having a viscosity in the range of 100 to 1,000,000 centipoise at 25 °C and a vinyl-terminated diorgauopalysiloxane having a viscosity in the range of 100 to 1,000,000 centipoise at 25°C where organo is a monovalent hydrocarbon with/a (2) polyalkoxy cross-linking agent of the formula, where R I is a C (1-8) monovalent hydrocarbon radical and R 2 is C (1-13) monovalent hydro- carbon radical and b is 0, 1 or 2; and (3) in the presence of a platinum catalyst.

Claim 3

The process of Claim 1 wherein there is present from at least 100% excass of the polyalkoxy cross-linking agent in the reaction mixture.

Claim 4

The process of Claim 2 wherein the silanol-terminated diorganpolysiloxane has the formula, where each R is independently selected from C (1-13) monovalent hydrocarbon radicals and n is an integer having a value of from about 50 to 2,500.

Claim 5

The process of Claim 3 wherein the reaction is carried out at a temperature in the range of 30-150°C.

Claim 6

The process of Claim 4 wherein the reaction is carried out in a time period of 30 minutes to 2 hours.

Claim 7

The process of Claim 5 wherein the reaction is carried out at atmospheric processes.

Claim 8

The process of Claim 6 wherein the reaction is carried out in an inert organic solvent.

Claim 9

The process of Claim 7 wherein after the reaction has proceeded to completion, the solvent is stripped off.

Claim 10

The process of Claim 8 wherein after the solvent is stripped off, there is anhydrously added to the composition from 1 to 700 parts by weight of a treated filler per 100 parts by weight as organopolysiloxane.

Claim 11

The process of Claim 9 wherein the filler is silazane treated fumed silica.

Claim 12

A on-component RTV composition in which the base alkoxy-containing polysiloxane is produced by the process of Claim 10 wherein. these can be anhydrously added to the composition additional ingredients including a condensation catalyst.

Claim 13

The process of Claim 8 wherein there is present from 1 to 500 parts per million of platinum as a solubilized platinum complex catalyst.

Claim 14

The process of Claim 12 wherein the solubilized platinum catalyst is platinum complexed with a tetra- vinyl dimethyldisiloxane.

Claim 15

A one-component RTV silicone composition in which the alkoxy-terminated diorganopolysiloxane is produced by the process of Claim 8 in which prior to the reaction there is added 1 to 700 parts of a filler.

Claim 16

The RTV silicone composition of Claim 14 wherein the filler is fumed silica treated with cyclopolysiloxanes.

Claim 17

The RTV silicone composition of Claim 14 wherein the filler is stearic acid treated calcium carbonate.

Claim 18

The composition of Claim 14 wherein there are added additional ingredients common to one-component RTV compositions in the reaction mixture prior to the reaction.

Claim 19

The camposition of Claim 17 wherein after the solvent has been stripped off, there is added a tin condensation catalyst.

Claim 20

A one-component RTV silicone rubber composition in which the alkoxy-terminated diorganopolysiloxane is produced by the process of Claim 8 wherein subsequent to the reaction there is added a scavenger of unbonded hydroxy groups.

Claim 21

The composition of Claim 19 wherein the scavenger for hydroxy-functional groups is a silicon-nitrogen compound selected from the class consisting of (a) a silicon-nitrogen compound having the formula where Y is selected from R''' and R" 2 N-- and (b) a silicon-nitrogen polymer comprising (1) from 3 to 100 mole percent chemically combined structural units selected from the class consisting of units. having the formula and (2). from 7 to 97 mole percent chemically combined structural units represented by the formula and. mixtures thereof where the silicon atoms of said silicon-nitrogen polymer are joined to each other by a member selected from an SiOSi linkage and a SiNR" Si linkage, the free valances of said silicon atoms other than those joined to oxygen to form a siloxy unit and nitrogen to form a silazy unit are joined to a member selected from an R" radical and (R" ) 2 N radical, and where the ratio of the sum of said R''' radicals and said (R" 2 N radicals to the silicon atoms of said silicon-nitrogen polymer has a value of 1.5 to 3, inclusive, and R" is a member selected from the class consisting of hydrogen and monovalent hydrocarbon radicals, and fluroalkyl radicals, R''' is a member selected from hydrogen, monovalent hydrocarbon radicals and fluroalkyL radicals, and c is a whole aumber equal to 0. to 3, inclusive.

Claim 22

The composition of Claim 20 wherein there is present from 0.5 to 10 parts by weight of the silicone scavenger per 100 parts by weight of the organopolysiloxane.

Claim 23

The composition of Claim 19 wherein the scavenger for hydroxy functional groups is selected from the class consisting of a non-cyclic silyl nitrogen scavenger of the formula. and cyclic silyl nitrogen scavengers having at least one or all of the units of the formula, and the rest of the units if any, having the formula where R 10 is a C (1-8) aliphatic organic radical selected from the group consisting of alkyl, alkylether, alkyl- ester, alkylketone, alkylcyano, and aryl, R 11 is a C (1-8) monovalent substituted or unsubstituted hydrocarbon radical, Q is selected from hydrogen, C (1-8) monovalent substituted or unsubstituted hydrocarbon radicals and radicals of the formula where R 10 , R 11 are as previously defined, where a varies from 0 to 2, f varies from 0 to 3, h is 0 or 1, where s is a whole number that varies from 1 to 25, d is a whole number that varies from 1 to 25, R 22 is selected from hydrogen and C (1-8) monovalent hydrocarbon radicals and R 23 is independently selected from C (1-8) hydrocarbon and hydrocarbonoxy radicals, A is selected from the class consisting of hydrogen and C (1-8) monovalent substituted or unsubstituted hydrocarbon radicals and radicals of the formula where R 10 , R 11 are as previously defined, g varies from 0 to 3 and in the above scavengers there is at least one hydrocarbonoxy group in the molecule, R 12 is defined the same as R 10 , and. R 13 is defined the same as R 11 , and R 14 is defined the same as R 11 .

Claim 24

The composition of Claim 19 wherein the silane scavenger for hydroxy functional groups has the formula, where R 1 is a C (1-8) aliphatic organic radical selected from the group consisting of alkyl, alkylether, alkylester, alkylketone, and alkylcyano radicals, or a C (7-13) aralkyl radical, R 2 is a C (1-13) monovalent substituted or unsubstituted hydrocarbon radical, X is a hydrolyzable leaving group selected from the group consisting of silazy, cyclic amido,. amido, amino, carbamato, enoxy, imidato, isocyanato, oximato, thioisocyanato and ureido radicals and,. a is a whole number equal to 0 to 3 inclusive, f is an integer equal to L to 4 inclusive and the sum of c+f is equal to L to 4 inclusive.

Claim 25

The composition of Claim 19 wherein the silane scavenger for hydroxy-functional groups has the formula where R I is a C (1-8) aliphatic organic radical selected from the group consisting of alkyl, alkylether, alkylester, alkylketone and alkylcyano radicals, or a C (7-13) aralkyl radical, R is a C (1-13) monovalent substituted or unsubstituted hydrocarbon radical, X is a hydrolyzable leaving: group consisting of cyclic amido, amido, amino, silazy carbamato, enoxy, imidato, isocyanato, oximato, thioiso- cyanato and ureido radicals; and a is an integer equal to 1 to 2 inclusive, b is a whole number equal to 0 to 1 inclusive, and the sum of b+a is. equal to 1 to 2 inclusive: and the silane is both the silane scavenger for hydroxy functional groups and. a polyalkoxysilane cross-linking agent.

Claim 26

The composition of Claim 19 wherein there is added to the composition additional amounts of a cross-linking agent of the formula, where R 1 , R 2 , are as previously identified, s is a whole number equal to 0, 1 or 2.

Claim 27

The composition of Claim 25 wherein there is added from 1 to 700 parts of filler per 100 parts of the alkoxy-terminated organopolysiloxanes.

Claim 28

The comnosition of Claim 26 wherein the filler is cyclopolysiloxane treated fumed silica.

Claim 29

. The composition of Claim 27 wherein the fumed silica is also treated with silazanes.

Claim 30

The composition of Claim 26 wherein the filler is stearic acid treated calcium carbonate.

Claim 31

The composition of Claim 29 wherein there is further added a condensation tin catalyst.

Claim 32

The composition of Claim 30 wherein there is further added additional ingredients that are common in one-component RTV silicone rubber compositions.

Claim 33

The process of Claim a wherein the hydrogen gas that is formed in the process is continuously stripped off during the reaction.

Claim 34

. The process of Claim L wherein the vinly-terminated diorganopolysiloxane has the formula, where Vi is vinyl, each R is independently selected from C (1-13) monovalent hydrocarbon radicals and t is a whole number that varies from 50 to about 2,500. The above Specification and Claims discloses and claims my invention.