Room temperature vulcanizable polymers
A room-temperature vulanizable (RTV) polymeric composition comprising organosiloxane or polyurethane units having at least one terminal methyl isopropyl ketoximino or methyl propyl ketoximino moiety, as well as methods of making the same.
1. A sealant composition comprising organosiloxane polymeric units having at least one terminal moiety according to Formula I:
wherein
Q is
R is independently selected from a branched or straight chain C 1 -C 8 alkyl or alkoxy, C 3 -C 6 cylcoalkyl, C 2 -C 5 alkenyl, or aryl, and
n is 2 or 3,
wherein said organosiloxane polymeric units are reaction products of:
(I) a hydroxyl end-capped organosiloxane having a structure according to Formula II(b):
wherein R 1 and R 2 are independently selected from methyl, ethyl, propyl, butyl, phenyl, methylphenyl, ethylphenyl, vinyl, allyl, cyclohexyl, tolyl, isopropyl, chloropropyl, 3,3,3-trifluoropropyl, chlorophenyl, beta-(perfluorobutyl)ethyl, and chlorocyclohexyl, and N is a number such that the hydroxyl end-capped organosiloxanes have a viscosity from about 2000 to about 150,000 centipoise at 25° C. and
(II) a silane cross-linking agent comprising a compound according to Formula III:
wherein R is as defined above in Formula I and n is 3 or 4;
wherein the sealant composition further comprises:
a catalyst that is present in an amount from 0.001 to 1.0% in the composition.
2. The sealant composition of claim 1 wherein, in Formula I, n=2 and R is methyl, ethyl, vinyl, or phenyl.
3. The sealant composition of claim 2 wherein Q is
4. The sealant composition of claim 2 wherein Q is
5. The sealant composition of claim 1 wherein said organosiloxane polymeric units have a viscosity from about 2000 to about 150,000 centipoise at 25° C.
6. The sealant composition of claim 5 wherein, in Formula II(b),
R 1 and R 2 are independently selected from methyl, ethyl, phenyl, vinyl, and 3,3,3-trifluoropropyl.
7. The sealant composition of claim 1 wherein, in Formula III, R is independently methyl, ethyl, vinyl, or phenyl.
8. The sealant composition of claim 7 wherein Q is
9. The sealant composition of claim 7 wherein Q is
10. The sealant composition of claim 1 wherein said silane cross-linking agent is selected from the group consisting of methyl tris-(methyl isopropyl ketoximino) silane, vinyl tris-(methyl isopropyl ketoximino)silane phenyl tris-(methyl isopropyl ketoximino)silane, ethyl tris-(methyl isopropyl ketoximino)silane, tetrakis-(methyl isopropyl ketoximino)silane, methyl tris-(methyl propyl ketoximino)silane, vinyl tris-(methyl propyl ketoximino)silane, phenyl tris-(methyl propyl ketoximino) silane, ethyl tris-(methyl propyl ketoximino)silane, and tetrakis-(methyl propyl ketoximino) silane.
11. The sealant composition of claim 1 wherein said silane cross-linking agent is selected from the group consisting of tris-(methyl isopropyl ketoximino)(methoxy)silane, tris-(methyl isopropyl ketoximino)(ethoxy)silane, tris-(methyl propyl ketoximino)(methoxy)silane, and tris-(methyl propyl ketoximino)(ethoxy)silane.
12. The composition of claim 1 , wherein the catalyst is an organotin catalyst.
13. The composition of claim 12 , wherein the organotin catalyst is dibutyltinlaurate.
14. The composition of claim 1 , further comprising a plasticizer comprising a triorganosilyl end-blocked diorganopolysiloxane having a viscosity from 10 to 100,000 centipoise at 25° C.
15. The composition of claim 14 , wherein the triorganosilyl end-blocked diorganopolysiloxane is present in the composition in an amount from 15 to 20% by weight.
16. The composition of claim 1 , further comprising a filler.
17. The composition of claim 16 , wherein the filler is a reinforcing filler, a non-reinforcing filler, or a mixture thereof.
18. The composition of claim 17 , wherein the filler comprises silica, calcium carbonate, or a mixture thereof.
19. The composition of claim 1 , further comprising a silane adhesion promoter.
20. The composition of claim 19 , wherein the silane adhesion promoter is an aminopropylalkoxysilane.
21. The composition of claim 20 , wherein the silane adhesion promoter is present in the composition in an amount from about 0.001 to about 2.5% by weight.
22. A sealant composition comprising organosiloxane polymeric units having at least one terminal moiety according to Formula I:
wherein
Q is
R is independently selected from a branched or straight chain C 1 -C 8 alkyl or alkoxy, C 3 -C 6 cylcoalkyl, C 2 -C 5 alkenyl, or aryl, and
n is 2 or 3,
wherein said organosiloxane polymeric units are reaction products of:
(I) a hydroxyl end-capped organosiloxane having a structure according to Formula II(b):
wherein R 1 and R 2 are independently selected from methyl, ethyl, propyl, butyl, phenyl, methylphenyl, ethylphenyl, vinyl, allyl, cyclohexyl, tolyl, isopropyl, chloropropyl, 3,3,3-trifluoropropyl, chlorophenyl, beta-(perfluorobutyl)ethyl, and chlorocyclohexyl, and N is a number such that the hydroxyl end-capped organosiloxanes have a viscosity from about 2000 to about 150,000 centipoise at 25° C. and
(II) a silane cross-linking agent comprising a compound according to Formula III:
wherein R is as defined above in Formula I and n is 3 or 4;
wherein the hydroxyl end-capped organosiloxane, prior to reaction with the silane cross-linking agent, represents from 39.15 to 66.9% by weight of the sealant composition; and
wherein the silane cross-linking agent, prior to reaction with the hydroxyl end-capped organosiloxane, represents from 2 to 5.7% by weight of the sealant composition.