Novel Scavengers for one-component RTV compositions

• US 4,839,453 A
• Filed: 10/21/1987
• Issued: 06/13/1989
• Est. Priority Date: 09/29/1982
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Swiger, Roger T., Chung, Rack H., Beers, Melvin D.
• Primary Examiner(s): Marquis, Melvyn I.
• Application Number:
  US07/113,411
• Time in Patent Office: 601 Days
• Field of Search: 528/18, 528/15, 528/17, 528/19, 528/21, 528/34, 528/23, 528/33, 528/901
• US Class Current: 528/18
• CPC Class Codes: C08K 5/17 Amines; Quaternary ammonium compounds
• CPC Class Codes: C08K 5/544 containing nitrogen
• CPC Class Codes: C08K 5/5445 containing at least one Si-N bond
• CPC Class Codes: C08L 83/04 Polysiloxanes
• CPC Class Codes: Y10S 528/901 Room temperature curable silicon-containing polymer

Abstract

A novel, shelf-stable, one-component alkoxy-functional RTV composition having therein as a scavenger an alkoxy-functional silazane compound. The silazane compound can be cyclic or linear and can also be an integrated cross-linking agent.

Claims

1. A stable, one-package, substantially anhydrous and substantially acid-free, room temperature vulcanizable organopolysiloxane composition stable under ambient conditions in the substantial absence of moisture over an extended period of time and convertible to a tack-free elastomer, comprising:

(A) an organopolysiloxane wherein the silicon atom at each polymer chain end is terminated with at least two alkoxy radicals;

(B) an effective amount of condensation catalyst; and

(C) a stabilizing amount of scavenger for hydroxy functional groups selected from the group consisting of;

##STR20## divinyltetramethoxydisilazane, 1-Methyl-3-ethyl-1,1,3,3-tetramethoxydisilazane,

1,3-Diethyl-1,1,3,3-tetramethoxydisilazane,

1-Methyl-3-propyl-1,1,3,3-tetramethoxydisilazane,

1-Ethyl-3-propyl-1,1,3,3-tetramethoxydisilazane,

1,3-Dipropyl-1,1,3,3-tetramethoxydisilazane,

1,1,3-Trimethyl-1,3,3-trimethoxydisilazane,

1,1-Dimethyl-3-ethyl-1,3,3-trimethoxydisilazane,

1,1-Dimethyl-3-propyl-1,3,3-trimethoxydisilazane,

1,1-Dimethyl-3-butyl-1,3,3-trimethoxydisilazane,

1,1-Diethyl-3-methyl-1,3,3-trimethoxydisilazane,

1,1-Dipropyl-3-methyl-1,3,3-trimethoxydisilazane,

1,1-Dibutyl-3-methyl-1,3,3-trimethoxydisilazane,

1,1,3-Trimethyl-1,3,3-trimethoxydisilazane,

1,1,3-Triethyl-1,3,3-trimethoxydisilazane,

1,1,3-Tripropyl-1,3,3-Trimethoxydisilazane,

1,1-Dimethyl-1,3,3,3-Tetramethoxydisilazane,

1,1-Diethyl-1,3,3,3-Tetramethoxydisilazane,

1,1-Dipropyl-1,3,3,3-Tetramethoxydisilazane,

7. The composition of claim 1 wherein the scavenger is a cyclic silazane where R¹², R¹³, and R¹⁴ are methyl.

9. A one-package, room temperature vulcanizable organopolysiloxane composition in accordance with claim 1, where the polyalkoxy-terminated organopolysiloxane has the formula, ##STR37## where R is a C_1-13 monovalent substituted or unsubstituted hydrocarbon radical, R¹ 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, R² is a C_1-13 monovalent substituted or unsubstituted hydrocarbon radical, X is a silazane hydrolyzable leaving group, and b is a whole number equal to 0 or 1, e is a whole number equal to 1 or 1 inclusive, and the sum of b+e is equal to 0 or 1 inclusive, and n is an integer having a value of from about 50 to about 2500, inclusive.

10. A room temperature vulcanizable composition in accordance with claim 1 having an effective amount of a cross-linking silane of the formula, ##STR38## where R¹ 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, R² is a C_1-13 monovalent substituted or unsubstituted hydrocarbon radical, and b is a whole number equal to 0 or 1.

11. A room temperature vulcanizable composition in accordance with claim 1, which contains a tin compound as the condensation catalyst.

2. 3-Dimethyl-1-ethoxyl -1,3,3-trimethoxydisilazane,

1,3-Diethyl-1-ethoxy-1,3,3-trimethoxydisilazane,

and cyclic silazane scavengers having at least one or all of the units of the formula:

##STR21## and the rest of the units, if any, having the formula;

##STR22## where h is 0 or 1, R¹² is a C_1-8 aliphatic organic radical selected from the group consisting of alkyl, alkylether, alkylester, alkylketone, alkyl cyano, and aryl and R¹³ and R¹⁴ is a C_1-8 monovalent substituted or unsubstituted hydrocarbon radical.

8. The composition of claim 2 wherein the scavenger is a cyclic silazane where R¹², R¹³, and R¹⁴ are methyl.

12. A room temperature vulcanizable composition in accordance with claim 8, where R, R¹ and R² are methyl and which has a tin compound as a condensation catalyst.

13. An RTV composition in accordance with claim 2 wherein the condensation catalyst is dibutyltindiacetate.

14. An RTV composition in accordance with claim 2 further comprising a polymethoxysilane cross-linking agent.

3. A stable, one-package, substantially anhydrous and substantially acid-free, room temperature vulcanizable organopolysiloxane composition stable under ambient conditions in the substantial absence of moisture over an extended period of time and convertible to a tack-free elastomer, comprising:

(A) an organopolysiloxane wherein the silicon atom at each polymer chain end is terminated with at least two alkoxy radicals;

(B) an effective amount of condensation catalyst; and

(C) a stabilizing amount of scavenger for hydroxy functional groups selected from the group consisting of;

##STR23## divinyltetramethoxydisilazane, 1-Methyl-3-ethyl-1,1,3,3-tetramethoxydisilazane,

1,3-Diethyl-1,1,3,3-tetramethoxydisilazane,

1-Methyl-3-propyl-1,1,3,3-tetramethoxydisilazane,

1-Ethyl-3-propyl-1,1,3,3-tetramethoxydisilazane,

1,3-Dipropyl-1,1,3,3-tetramethoxydisilazane,

1,1,3-Trimethyl-1,3,3-trimethoxydisilazane,

1,1-Dimethyl-3-ethyl-1,3,3-trimethoxydisilazane,

1,1-Dimethyl-3-propyl-1,3,3-trimethoxydisilazane,

1,1-Dimethyl-3-butyl-1,3,3-trimethoxydisilazane,

1,1-Diethyl-3-methyl-1,3,3-trimethoxydisilazane,

1,1-Dipropyl-3-methyl-1,3,3-trimethoxydisilazane,

1,1-Dibutyl-3-methyl-1,3,3-trimethoxydisilazane,

1,1,3-Trimethyl-1,3,3,-trimethoxydisilazane,

1,1,3-Triethyl-1,3,3-trimethoxydisilazane,

1,1,3-Tripropyl-1,3,3-Trimethoxydisilazane,

1,1-Dimethyl-1,3,3,3-Tetramethoxydisilazane,

1,1-Diethyl-1,3,3,3-Tetramethoxydisilazane,

1,1-Dipropyl-1,3,3,3-Tetramethoxydisilazane,

1,3-Dimethyl-1-ethoxyl -1,3,3-trimethoxydisilazane,

1,3-Diethyl-1-ethoxy-1,3,3-trimethoxydisilazane,

and cyclic silazane scavengers having at least one or all of the units of the formula;

##STR24## and the rest of the units, if any, having the formula;

##STR25## where h is 0 or 1, R¹² is a C_1-8 aliphatic organic radical selected from the group consisting of alkyl, alkylether, alkylester, alkylketone, alkyl cyano, and aryl and R¹³ and R¹⁴ is a C_1-8 monovalent substituted or unsubstituted hydrocarbon radical and

(D) an effective amount of a curing accelerator consisting of an amine or mixture of amine.

15. The composition of claim 3 wherein the scavenger is a cyclic silazane where R¹², R¹³, and R¹⁴ are methyl.

16. A one-package room temperaure vulcanizable composition in accordance with claim 3 wherein R, R¹ and R² are methyl.

17. A one-package room temperature vulcanizable composition in accordance with claim 3 wherein the condensation catalyst is a tin compound.

18. A one-package room temperature vulcanizable composition in accordance with claim 3 where the polyalkoxysilane is methyltrimethoxysilane.

19. A one-package RTV composition in accordance with claim 3 where the amine is butyltetramethylguanidine.

20. A composition in accordance with claim 3 where the condensation catalyst is dibutyltindiacetate.

21. A room temperature vulcanizable composition in accordance with claim 18 having an effective amount of di-n-hexylamine curing accelerator.

4. A stable, one-package, substantially anhydrous and substantially acid-free, room temperature vulcanizable organopolysiloxane composition stable under ambient conditions in the substantial absence of moisture over an extended period of time and convertible to a tack-free elastomer, comprising:

(A) 100 parts of substantially silanol-free polyalkoxysiloxydiorganopolysiloxane of the formula;

##STR26## wherein R is selected from C_1-13 monovalent hydrocarbon radicals, halogenated hydrocarbon radicals or cyanoalkyl radicals;

R¹ is selected from C_1-8 alkyl radicals or C_7-13 aralkyl radicals;

R² is selected from methyl, phenyl or vinyl;

X is a silazane leaving group;

e is 0 or 1 and b+e is 0 or 1,

(B) 0 to 10 parts of a cross-linking polyalkoxy silane of the formula;

##STR27## where R¹ and R² are defined above and b is 0 or 1, (C) an effective amount of a condensation catalyst,

(D) a stabilizing amount of scavenger for hydroxy functional groups selected from the group consisting of;

##STR28## and cyclic silazanes scavengers having at least one or all of the units of the formula;

##STR29## and the rest of the units, if any, having the formula;

##STR30## where h is 0 or 1, R¹² is a C_1-8 aliphatic organic radical selected from the group consisting of alkyl, alkylether, alkylester, alkylketone, alkyl cyano, and aryl and R¹³ and R¹⁴ is a C_1-8 monovalent substituted or unsubstituted hydrocarbon radical; and

(E) 0.1 to 5 parts of a curing accelerator consisting of an amine or mixture of amines.

5. A stable, one-package, substantially anhydrous and substantially acid-free, room temperature vulcanizable organopolysiloxane composition stable under ambient conditions in the substantial absence of moisture over an extended period of time and convertible to a tack-free elastomer, comprising:

(A) an organopolysiloxane wherein the silicon atom at each polymer chain end is terminated with at least two alkoxy radicals;

(B) an effective amount of condensation catalyst; and

(C) a stabilizing amount of scavenger for hydroxy functional groups having the general formula;

##STR31## wherein R¹⁰ is a C_1-8 aliphatic organic radical selected from the group consisting of alkyl, alkylether, alkylester, alkylketone and alkylcyano or aryl;

R¹¹ is a C_1-8 monovalent substituted or unsubstituted hydrocarbon radical;

Q is selected from hydrogen, C_1-8 monovalent substituted hydrocarbon radicals or radicals of the formula;

##STR32## where R¹⁰ and R¹¹ are as previously defined;

a varies from 0 to 2;

f varies from 0 to 3;

s is a whole number that varies from 1 to 25;

d is a whole number that varies from 1 to 25;

R²² is selected from hydrogen or C_1-8 monovalent hydrocarbon radicals;

R²³ is independently selected from C_1-8 hydrocarbon or hydrocarbonoxy radicals;

A is a radical of the formula;

##STR33## where R¹⁰ and R¹¹ 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.

6. A stable, one-package, substantially anhydrous and substantially acid-free, room temperature vulcanizable organopolysiloxane composition stable under ambient conditions in the substantial absence of moisture over an extended period of time and convertible to a tack-free elastomer, comprising:

(A) an organopolysiloxane wherein the silicon atom at each polymer chain end is terminated with at least two alkoxy radicals;

(B) an effective amount of condensation catalyst; and

(C) a stablizing amount of scavenger for hydroxy functional groups having the general formula;

##STR34## where R¹⁰ is a C_1-8 aliphatic organic radical selected from the group consisting of alkyl, alkylether, alkylester, alkylketone and alkylcyano or aryl;

R¹¹ is a C_1-8 monovalent substituted or unsubstituted hydrocarbon radical;

Q is a radical of the formula;

##STR35## where R¹⁰ and R¹¹ are as previously defined;

a varies from 0 to 2;

f varies from 0 to 3;

s is a whole number that varies from 1 to 25;

d is a whole number that varies from 1 to 25;

R²² is selected from hydrogen or C_1-8 monovalent hydrocarbon radicals;

R²³ is independently selected from C_1-8 hydrocarbon or hydrocarbonoxy radicals;

A is selected from the group consisting of hydrogen, C_1-8 monovalent substituted hydrocarbon radicals, C_1-8 monovalent unsubstituted hydrocarbon radicals and radicals of the formula;

##STR36## where R¹⁰ and R¹¹ 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.