Scavengers for one-component alkoxy-functional RTV compositions and processes

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 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 silicone scavenger compound for hydroxy functional groups, selected from the group consisting of P1 (A) a silicon-nitrogen compound having the formula ##STR39## where Y is selected from R'" and R".sub.2 N-- and (B) a silicon nitrogen polymer comprising (1) from 3 to 100 mole percent chemically combined structured units selected from the group consisting of units having the formula ##STR40## and (2) from 0 to 97 mole percent chemically combined structural units represented by the formula ##STR41## 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 valences 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").sub.2 N radical, and where the ratio of the sum of said R'" radicals and said (R").sub.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 group consisting of hydrogen, monovalent hydrocarbon radicals, and fluoroalkyl radicals, R'" is a member selected from the group consisting of hydrogen, monovalent hydrocarbon radicals and fluoroalkyl radicals, and c is a whole number equal to 0 to 3, inclusive, and (4) an effective amount 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 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 polyalkoxy-siloxydiorganopolysiloxane of the formula ##STR56## (ii) 0 to 10 parts of a cross-linking polyalkoxysilane of the formula ##STR57## (iii) an effective amount of a condensation catalyst, (iv) a stabilizing amount of a silicone scavenger compound for hydroxy functional groups which is a silicon-nitrogen compound selected from the group consisting of
• (A) a silicon-nitrogen compound having the formula ##STR58## where Y is selected from R'" and R".sub.2 N- and (B) a silicon-nitrogen polymer comprising (1) from 3 to 100 mole percent chemically combined structural units selected from the group consisting of units having the formula ##STR59## and (2) from 0 to 97 mole percent chemically combined structural units represented by the formula ##STR60## 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 valences 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").sub.2 N radical, and where the ratio of the sum of said R'" radicals and said (R").sub.2 N radicals to the silicon atoms of said silicon-nitrogen polymer has a value of 1.5 to 3, inclusive, where R" is a member selected from the group consisting of hydrogen, monovalent hydrocarbon radicals, and fluoroalkyl radicals, R'" is a member selected from the group consisting of hydrogen, monovalent hydrocarbon radicals and fluoroalkyl radicals, and c is a whole number equal to 0 to 3, inclusive, 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, and b is a whole number equal to 0 or 1, and n is an integer having a value of from about 50 to about 2500 inclusive;
• and (v) 0 to 5 parts of a curing accelerator selected from the group consisting of substituted guanidines, amines and mixtures thereof.

A method of making a one-package and substantially acid-free room temperature vulcanizable composition curable to the solid elastomeric state, which method comprises agitating under substantially anhydrous conditions at a temperature in the range of from 0.degree. C. to 180.degree. C., a room temperature vulcanizable material selected from

• (i) a mixture comprising
• (A) 100 parts of a silanol-terminated polydiorganosiloxane consisting essentially of chemically combined units of the formula ##STR61## (B) from 1 to 10 parts of an alkoxy-functional cross-linking silane of the formula ##STR62## (C) 0 to 5 parts of a curing accelerator selected from the group consisting of substituted guanidines, amines and mixtures thereof,
• (D) a stabilizing amount of silicone scavenger compound for hydroxy functional groups, selected from a silicon-nitrogen compound having the formula, ##STR63## where Y is selected from R'" and R".sub.2 N-- and a silicon-nitrogen polymer comprising (1) from 3 to 100 mole percent chemically combined structural units selected from the group consisting of units having the formula ##STR64## and (2) from 0 to 97 mole percent chemically combined structural units represented by the formula ##STR65## 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 valences 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").sub.2 N radical, and where the ratio of the sum of said R'" radicals and said (R").sub.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 group consisting of hydrogen, monovalent hydrocarbon radicals, and fluoroalkyl radicals, R'" is a member selected from the group consisting of hydrogen, monovalent hydrocarbon radicals and fluoroalkyl radicals, and c is a whole number equal to 0 to 3, inclusive;
• and
• (E) an effective amount of a condensation catalyst, and
• (ii) a mixture comprising
• (A) 100 parts of a polyalkoxy-terminated polydiorganosiloxane of the formula ##STR66## (B) 0 to 10 parts of a cross-linking silane of the formula ##STR67## (C) an effective amount of a condensation catalyst (D) a stabilizing amount of the silicone scavenger for hydroxy functional groups of (i) (D), and
• (E) 0 to 5 parts of a curing accelerator selected from the group consisting of substituted guanidines, amines and mixtures thereof, where b is 0 or 1, inclusive;
• R is selected from C.sub.(1-13) monovalent substituted or unsubstituted hydrocarbon radicals, 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) alkaryl radical, R.sup.2 is a C.sub.(1-13) monovalent substituted or unsubstituted hydrocarbon radical.

A mixture comprising

• (A) 100 parts of a silanol-terminated polydiorganosiloxane consisting essentially of chemically combined units of the formula ##STR68## (B) 1 to 10 parts of a cross-linking silane of the formula ##STR69## (C) 0 to 5 parts of a curing accelerator selected from the group consisting of substituted guanidines, amines and mixtures thereof,
• (D) a stabilizing amount of a silicone scavenger compound of hydroxy functional groups selected from a silicon-nitrogen compound having the formula ##STR70## where Y is selected from R'" and R".sub.2 N-- and a silicon-nitrogen polymer comprising (1) from 3 to 100 mole percent chemically combined structural units selected from the group consisting of units having the formula ##STR71## and (2) from 0 to 97 mole percent chemically combined structural units represented by the formula ##STR72## 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").sub.2 N radical, and where the ratio of the sum of said R'" radicals and said (R").sub.2 N radicals to the silicon atoms of said silicon-nitrogen polymer has a value of 1.5 to 3, inclusive, where R" is a member selected from the group consisting of hydrogen, monovalent hydrocarbon radicals, and fluoroalkyl radicals, R'" is a member selected from the group consisting of hydrogen, monovalent hydrocarbon radicals and fluoroalkyl radicals, and c is a whole number equal to 0 to 3, inclusive, and
• (E) an effective amount of a condensation catalyst, where R is selected from C.sub.(1-13) monovalent substituted or unsubstituted hydrocarbon radicals, 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, b is a whole number equal to 0 or 1.

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 a silanol-terminated organopolysiloxane and polyalkoxysilane cross-linking agent, characterized in the improvement which comprises adding to the organopolysiloxane mixture a stabilizing amount of a silicone scavenger compound which is a scavenger for hydroxy functional groups selected from (A) a silicon-nitrogen compound having the formula, ##STR73## where Y is selected from R'" and R".sub.2 N-- and (B) a silicon-nitrogen polymer comprising (1) from 3 to 100 mole percent chemically combined structural units selected from the group consisting of units having the formula ##STR74## and (2) from 0 to 97 mole percent chemically combined structural units represented by the formula ##STR75## 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 valences 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").sub.2 N radical, and where the ratio of the sum of said R'" radicals and said (R").sub.2 N radicals to the silicon atoms of said silicon-nitrogen polymer has a value of 1.5 to 3, inclusive, where R" is a member selected from the group consisting of hydrogen, monovalent hydrocarbon radicals, and fluoroalkyl radicals, R'" is a member selected from the group consisting of hydrogen, monovalent hydrocarbon radicals and fluoroalkyl radicals, and c is a whole number equal to 0 to 3, inclusive and thereafter adding an effective amount of a condensation catalyst.

In the method of making a substantially acid-free room temperature vulcanizable organopolyslixoane 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, characterized in the improvement which comprises adding to said polyalkoxy-terminated organopolysiloxane a stabilizing amount of a silicone scavenger compound for hydroxy functional groups, selected from (A) a silicon-nitrogen compound having the formula ##STR76## where Y is selected from R'" and R".sub.2 N-- and (B) a silicon-nitrogen polymer comprising from 3 to 100 mole percent chemically combined structural units selected from the group consisting of units having the formula ##STR77## and from 0 to 97 mole percent chemically combined structural units represented by the formula ##STR78## 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 valences 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").sub.2 N radical, and where the ratio of the sum of said R'" radicals and said (R").sub.2 N radicals to the silicon atoms of said silicon-nitrogen polymer has a value of 1.5 to 3, inclusive, where R" is a member selected from the group consisting of hydrogen, monovalent hydrocarbon radicals, and fluoroalkyl radicals, R'" is a member selected from the group consisting of hydrogen, monovalent hydrocarbon radicals and fluoroalkyl radicals, and c is a whole number equal to 0 to 3, inclusive, an effective amount of a condensation catalyst, whereby improved stability is achieved in the resulting room temperature vulcanizable organopolysiloxane composition.

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 which is a silyl amine of the formula ##STR89## where R" is a radical selected from the group consisting of hydrogen, and C.sub.(1-8) monovalent hydrocarbon radicals R.sup.20 is selected from C.sub.(1-8) monovalent hydrocarbon radicals, C.sub.(1-8) alkoxy radicals and fluoroalkyl radicals, and g is a whole number that varies from 1 to 3, h is a whole number that varies from 0 to 2 and the sum of g+h does not exceed 3;
• and (4) an effective amount 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 polyalkoxy-terminated organpolysiloxane 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 ##STR91## (ii) 0 to 10 parts of a cross-linking polyalkoxysilane of the formula ##STR92## (iii) an effective amount of a condensation catalyst, and (iv) a stabilizing amount of a silane scavenger for hydroxy functional groups which is a silyl amine of the formula ##STR93## where R" is a radical selected from the group consisting of hydrogen, and C.sub.(1-8) monovalent hydrocarbon radicals, R.sup.20 is selected from C.sub.(1-8) monovalent hydrocarbon radicals C.sub.(1-8) alkoxy radicals and fluoroalkyl radicals and g is a whole number that varies from 1 to 3, h is a whole number that varies from 0 to 2 and the sum of h+g does not exceed 3, 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 C.sub.(1-13) monovalent substituted or unsubstituted hydrocarbon radical and b is a whole number equal to 0 or 1, and n is an integer having a value of from about 50 to about 2500 inclusive;
• (v) 0 to 5 parts of a curing accelerator selected from the group consisting of substituted guanidines, amines and mixtures thereof.

A method of making a one-package and substantially acid-free room temperature vulcanizable composition curable to the solid elastomeric state, which method comprises agitating under substantially anhydrous conditions at a temperature in the range of from 0.degree. C. to 180.degree. C. a room temperature vulcanizable material selected from

• (i) a mixture comprising
• (A) 100 parts of a silanol-terminated polydiorganosiloxane consisting essentially of chemically combined units of the formula ##STR94## (B) 1 to 10 parts of cross-linking silane of the formula ##STR95## (C) 0 to 5 parts of a curing accelerator selected from the group consisting of substituted guanidines, amines and mixtures thereof;
• (D) a stabilizing amount of a silane scavenger for hydroxy functional groups which is a silyl amine of the formula ##STR96## where R" is a radical selected from the group consisting of hydrogen, and C.sub.(1-8) monovalent hydrocarbon radicals, R.sup.20 is selected from the group consisting of C.sub.(1-8) monovalent hydrocarbon radicals, C.sub.(1-8) alkoxy radicals and fluoroalkyl radicals and g is a whole number that varies from 1 to 3, h is a whole number that varies from 0 to 2 and the sum of g+h does not exceed 3;
• and
• (E) an effective amount of a condensation catalyst, and
• (ii) a mixture comprising
• (A) 100 parts of a polyalkoxy-terminated polydiorganosiloxane of the formula ##STR97## (B) 0 to 10 parts of a cross-linking silane of the formula ##STR98## (C) an effective amount of a condensation catalyst (D) a stabilizing amount of the silicone scavenger for hydroxy functional groups of (i) (D), and
• (E) 0 to 5 parts of a curing accelerator selected from the group consisting of substituted guanidines, amines and mixtures thereof, where R is selected from C.sub.(1-13) monovalent substituted or unsubstituted hydrocarbon radicals, 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) alkaryl radical, R.sup.2 is a C.sub.(1-13) monovalent substituted or unsubstituted hydrocarbon radical, b is a whole number equal to 0 or 1, n is an integer having a value of from about 50 to about 2500 inclusive.

A mixture comprising

• (i) 100 parts of a silanol-terminated polydiorganosiloxane consisting essentially of chemically combined units of the formula ##STR99## (ii) 1 to 10 parts of a cross-linking silane of the formula ##STR100## (iii) 0 to 5 parts of a curing accelerator selected from the group consisting of substituted guanidines, amines and mixtures thereof,
• (iv) a stabilizing amount of a silane scavenger for hydroxy functional groups which is a silyl amine of the formula ##STR101## where R" is a radical selected from the group consisting of hydrogen, and C.sub.(1-8) monovalent hydrocarbon radicals, R.sup.20 is selected from C.sub.(1-8) monovalent hydrocarbon radicals C.sub.(1-8) alkoxy radicals and fluoroalkyl radicals, and g is a whole number that varies from 1 to 3, h is a whole number that varies from 0 to 2 and the sum of g+h does not exceed 3,
• (v) an effective amount of a condensation catalyst, and
• where R is selected from C.sub.(1-13) monovalent substituted or unsubstituted hydrocarbon radicals, 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.(1-13) aralkyl radical, R.sup.2 is a C.sub.(1-13) monovalent substituted or unsubstituted hydrocarbon radical, b is a whole number equal to 0 or 1.