Curable silicone compositions that cure through command catalysis
Inhibited tin or titanate catalysts are used in condensation cures of silicone materials. Such catalysts are command cure systems with long open pot life, yet have relatively fast cure when the cure mechanism is triggered. This combines the advantages of the inhibited addition cure systems (command cure) with the advantages of the condensation cure systems (lower cost).
1. A composition of matter comprising (A.) a silicone composition that cures through silanol condensation reactions and (B.) a command cure catalyst, wherein said command cure catalyst is selected from the group comprising:
a. a tin compound selected from the group of formulae consisting of:
i. Sn(Y) n (X) 4-n wherein Y is a sulfide group with the general formula RS − is a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms or an aryl group containing 6 to 20 carbon atoms, X is selected from an linear, branched, or cyclic alkoxy group, an enoloxy group, or a carboxylate ester having 1 to 20 carbon atoms, n has a value of 1, 2, 3, or 4, and 1≤n≤4;
ii. Sn(Y) n (X) 2-n wherein Y is a sulfide polydentate ligand, X is a linear, branched, or cyclic alkoxy group, an amine, or a carboxylate ester, having 1 to 20 carbon atoms, wherein 1≤n≤2;
iii. Sn(Y)(X) wherein Y is a sulfide tridentate ligand with the general formula − SARA wherein R is a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms and wherein A is S − ,O − , or COO − , X is a linear, branched or cyclic alkoxy, enoloxy, or carboxylate ester having 1 to 20 carbons atoms;
b. a titanate compound selected from the formulae consisting of:
i. Ti(X) n wherein X is a polydentate ligand with the general formula ARARARA wherein R is a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms and A is selected from N, O − , or COO − .
2. A composition of matter as claimed in claim 1 wherein the command cure catalyst is dibutyltin bis-(trimethoxysilyl mercaptide).
3. A composition of matter as claimed in claim 1 wherein the command cure catalyst is triethoxyamine titanium.
4. A composition of matter as claimed in claim 1 that is:
a. 65 parts methoxy end block polydimethylsiloxane having a viscosity of 2000 cPs;
b. 10 parts of treated fumed silica;
c. 20 parts of treated precipitated calcium carbonate;
d. 4 parts pigment, and,
e. 1 part of dibutyltin bis(trimethoxysilylpropyl mercaptide).
5. A composition of matter as claimed in claim 1 that is:
a. 65 parts methoxy end block polydimethylsiloxane having a viscosity of 2000 cPs;
b. 10 parts of treated fumed silica;
c. 20 parts of treated precipitated calcium carbonate;
d. 4 parts pigment, and,
e. 1 part of dibutyltin bis(dodecylmercaptide).
6. A composition of matter as claimed in claim 1 that is:
a. 65 parts methoxy end block polydimethylsiloxane having a viscosity of 2000 cPs;
b. 10 parts of treated fumed silica;
c. 20 parts of treated precipitated calcium carbonate;
d. 4 parts pigment, and,
e. 1 part of triethoxyamine titanium.