One package, stable, moisture curable, polyalkoxy-terminated organopolysiloxane compositions and method for making
AssigneeGeneral Electric Company
InventorsMary A. White, Melvin D. Beers, Gary M. Lucas, Robert A. Smith, Roger T. Swiger
Life of this patent
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Abstract
Stable, substantially acid-free, one package moisture curable polyalkoxy-terminated organopolysiloxane compositions are provided having a condensation catalyst such as a tin compound. A method for making the aforesaid moisture curable organopolysiloxane compositions, is also provided.
Claims36
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:
- (1) an organopolysiloxane wherein the silicon atom at each polymer chain end is terminated with at least 2 alkoxy radicals;
- (2) an effective amount of a condensation catalyst;
- (3) a stabilizing amount of silane scavenger for hydroxy functional groups having the formula ##STR14## where R.sup.1 is a C.sub.(1-8) aliphatic organic radical selected from the group consisting of alkyl, alkylether, alkylester, alkylketone, and alkylcyano radicals, or a C.sub.(7-13) aralkyl radical, R.sup.2 is a C.sub.(1-13) monovalent substituted or unsubstituted hydrocarbon radical, X is a hydrolyzable leaving group selected from the group consisting of amido, amino, carbamato, enoxy, imidato, isocyanato, oximato, thioisocyanato and ureido radicals and, c is a whole number equal to 0 to 3 inclusive, f is an integer equal to 1 to 4 inclusive and the sum of c+f is equal to 1 to 4 inclusive;
- and where X is enoxy or amido, (4) an effective amount of a curing accelerator selected from the group consisting of substituted guanidines, amines and mixtures thereof.
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:
- (1) an organopolysiloxane wherein the silicon atom at each polymer chain end is terminated with at least 2 alkoxy radicals;
- (2) an effective amount of a condensation catalyst;
- (3) a stabilizing amount of silane scavenger for hydroxy functional groups having the formula ##STR16## where R.sup.1 is a C.sub.(1-8) aliphatic organic radical selected from the group consisting of alkyl, alkylether, alkylester, alkylketone and alkylcyano radicals, or a C.sub.(7-13) aralkyl radical, R.sup.2 is a C.sub.(1-13) monovalent substituted or unsubstituted hydrocarbon radical, X is a hydrolyzable leaving group selected from the group consisting of amido, amino, carbamato, enoxy, imidato, isocyanato, oximato, thioisocyanato and ureido radicals and, c is a whole number equal to 0 to 3 inclusive, f is an integer equal to 1 to 4 inclusive and the sum of c+f is equal to 1 to 4 inclusive;
- and (4) an effective amount of a curing accelerator selected from the group consisting of substituted guanidines, amines and mixtures thereof.
A stable, one-package, substantially anhydrous and substantially acid-free, room temperature vulcanizable composition comprising a polymethoxy-terminated polydimethylsiloxane, an effective amount of a tin containing condensation catalyst, and a stabilizing amount of a polymethoxydi-n-hexylaminosilane.
A stable, one-package, substantially anhydrous and substantially acid-free, room temperature vulcanizable composition comprising a polymethoxy-terminated polydimethylsiloxane, and effective amount of a tin containing condensation catalyst, an effective amount of trimethoxysilylpropyltetramethylguanidine curing accelerator and a stabilizing amount of a polymethoxyacetamidosilane.
A stable and substantially acid-free, one-package room temperature vulcanizable polyalkoxy-terminated organopolysiloxane composition curable under ambient conditions to a tack-free elastomer over an extended period of time comprising on a weight basis,
- (i) 100 parts of a substantially silanol-free polyalkoxysiloxydiorganopolysiloxane of the formula ##STR19## (ii) 0 to 10 parts of a cross-linking polyalkoxysilane of the formula ##STR20## (iii) an effective amount of a condensation catalyst, and (iv) a stabilizing amount of a silane scavenger for hydroxy functional groups having the formula ##STR21## where R is a C.sub.(1-13) monovalent substituted or unsubstituted hydrocarbon radical, R.sup.1 is a C.sub.(1-8) aliphatic organic radical selected from the group consisting of alkyl, alkylether, alkylester, alkylketone and alkylcyano radicals, or a C.sub.(7-13) aralkyl radical, R.sup.2 is a C.sub.(1-13) monovalent substituted or unsubstituted hydrocarbon radical, X is a hydrolyzable leaving group selected from the group consisting of amido, amino, carbamato, enoxy, imidato, isocyanato, oximato, thioisocyanato and ureido radicals and, b is a whole number equal to 0 or 1, e is a whole number equal to 0 to 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, c is a whole number equal to 0 to 3 inclusive, f is an integer equal to 1 to 4 inclusive and the sum of c+f is equal to 1 to 4 inclusive;
- and (v) where X is enoxy, 0.1 to 5 parts of a curing accelerator selected from the group consisting of substituted guanidines, amines and mixtures thereof.
A stable and substantially acid-free, one-package, room temperature vulcanizable composition comprising a polymethoxy-terminated polydimethylsiloxane, a polymethoxysilane, an effective amount of a curing accelerator selected from the group consisting of substituted guanidines, amines and mixtures thereof, an effective amount of a tin compound condensation catalyst, and a stabilizing amount of a silane scavenger for hydroxy functional groups having at least one hydrolyzable leaving group selected from the group consisting of amido, amino, carbamato, enoxy, imidato, isocyanato, oximato, thioisocyanato and ureido radicals.
A substantially acid-free room temperature vulcanizable composition comprising methyldimethoxysiloxy terminated polydimethylsiloxane, a reinforcing amount of octamethylcyclotetrasiloxane treated silica filler, an effective amount of dibutyltindiacetate condensation catalyst, a cure accelerating amount of trimethoxysilylpropyltetramethylguanidine and an excess of up to 3% by weight, based on the weight of the polydimethylsiloxane of methyldimethoxy-(N-methylacetamido)silane.
In the method of making a substantially acid-free room temperature vulcanizable organopolysiloxane composition under substantially anhydrous conditions utilizing an effective amount of a condensation catalyst with an organopolysiloxane wherein the silicon atom at each polymer chain end is terminated with at least two alkoxy radicals, the improvement which comprises adding to said polyalkoxy-terminated organopolysiloxane (1) a stabilizing amount of a silane scavenger for hydroxy functional groups of the formula ##STR22## where R.sup.1 is a C.sub.(1-8) aliphatic organic radical selected from the group consisting of alkyl, alkylether, alkylester, alkylketone and alkylcyano radicals, or a C.sub.(7-13) aralkyl radical, R.sup.2 is a C.sub.(1-13) monovalent substituted or unsubstituted hydrocarbon radical, X is a hydrolyzable leaving group selected from the group consisting of amido, amino, carbamato, enoxy, imidato, isocyanato, oximato, thioisocyanato and ureido radicals and, c is a whole number equal to 0 to 3 inclusive, f is an integer equal to 1 to 4 inclusive, and the sum of c+f is equal to 1 to 4 inclusive, and (2) an effective amount of a condensation catalyst, whereby improved stability is achieved in the resulting room temperature vulcanizable organopolysiloxane composition, and (3) where X is enoxy, adding before or with the scavenger an effective amount of a curing accelerator selected from the group consisting of substituted guanidines, amines and mixtures thereof.
Dependencies are inferred from the claim text.