Low temperature platinum-vinylpolysiloxane hydrosilylation catalyst
Hydrosilation catalysts are provided in the form of platinum-MQ siloxanes. The platinum-MQ siloxane catalyst can be made directly from platinum-complexes containing at least one ligand and the desired MQ siloxane resin. The platinum-MQ siloxane catalyst can be employed as hydrosilation catalysts to make curable organopolysiloxane compositions.
1 . A platinum containing hydrosilylation catalyst comprising at least one monosiloxy unit possessing carbon-carbon double bond functionality and at least one tetrasiloxy unit.
2 . The platinum containing hydrosilylation catalyst of claim 1 wherein the catalyst has the formula:
Pt f (M a M vi b Q c ) g
wherein:
each occurrence of M is independently selected from the group consisting of R 1 3 SiO 1/2 , HO 1/2 , and R 1 O 1/2 and wherein each occurrence of R 1 is independently a monovalent hydrocarbon group containing from 1 to 30 carbon atoms;
each occurrence of M vi is independently R 2 x R 3 3-x SiO 1/2 wherein each occurrence of R 2 is independently a monovalent hydrocarbon group containing from 1 to 30 carbon atoms possessing at least one unsaturated carbon-carbon double bond and each occurrence of R 3 is a monovalent hydrocarbon group containing from 1 to 30 carbon atoms;
each occurrence of Q is independently SiO 4/2 ;
each occurrence of the subscripts a, b, c, f, g and x is independently an integer wherein a is 0 to 200; b is 1 to 202; c is 1 to 100; f is 1 to 100; g is 1 to 150; and x is 1 to 3.
3 . The hydrosilylation catalyst of claim 2 wherein each occurrence of M is independently R 1 3 SiO 1/2 , wherein each occurrence of R 1 is a monovalent hydrocarbon group containing from 1 to 6 carbon atoms, R 2 is an monovalent hydrocarbon group containing from 1 to 6 carbon atoms possessing at least one terminal carbon-carbon double bond, R 3 is a monovalent hydrocarbon group containing from 1 to 6 carbon atoms, each a, b, c, f, g and x is an integer, wherein a from 0 to 10; b is from 2 to 15, c is from 2 to 10, f is from 1 to 2, g is from 1 to 4, and most specifically from 1 to 2; and x is 1.
4 . The hydrosilylation catalyst of claim 2 wherein said catalyst is a single compound of said formula or a mixture of compounds of said formula.
5 . The hydrosilylation catalyst of claim 2 wherein R 1 is methyl, R 2 is vinyl and R 3 is methyl.
6 . The hydrosilylation catalyst of claim 1 wherein said catalyst is a solid.
7 . A platinum containing hydrosilylation catalyst prepared by a process comprising:
i) mixing at least one platinum-complex containing at least one ligand which is substantially absent of tetrasiloxy units, and a polyorganosiloxane resin containing at least one monosiloxy unit possessing carbon-carbon double bond functionality and at least one tetrasiloxy unit; and
ii) exchanging a ligand of the platinum-complex containing at least one ligand with the polyorganosiloxane resin under exchange conditions to provide said platinum containing hydrosilylation catalyst.
8 . The process of claim 7 wherein the polyorganosiloxane resin has the formula:
M a M vi b Q c
wherein:
each occurrence of M is independently selected from the group consisting of R 1 3 SiO 1/2 , HO 1/2 , and R 1 O 1/2 and wherein each occurrence of R 1 is independently a monovalent hydrocarbon group containing from 1 to 30 carbon atoms;
each occurrence of M vi is independently R 2 x R 3 3-x SiO 1/2 wherein each occurrence of R 2 is independently a monovalent hydrocarbon group containing from 1 to 30 carbon atoms possessing at least one unsaturated carbon-carbon double bond and each occurrence of R 3 is a monovalent hydrocarbon group containing from 1 to 30 carbon atoms;
each occurrence of Q is independently SiO 4/2 ;
each occurrence of the subscripts a, b, c, and x is independently an integer wherein a is 0 to 200; b is 1 to 202; c is 1 to 100; and x is 1 to 3.
9 . The process of claim 7 wherein the platinum-complex containing at least one ligand has the formula:
Pt 2 (M vi M vi ) 3 ;
wherein each occurrence of M vi is independently R 2 x R 3 3-x SiO 1/2 , wherein each occurrence of R 2 is independently a monovalent hydrocarbon group containing from 1 to 30 carbon atoms possessing at least one unsaturated carbon-carbon double bond, each occurrence of R 3 is a monovalent hydrocarbon group containing from 1 to 30 carbon atoms and each occurrence of x is from 1 to 3.
10 . The process of claim 7 wherein the platinum containing hydrosilylation catalyst has the formula:
Pt f (M a M vi b Q c ) g
wherein:
each occurrence of M is independently selected from the group consisting of R 1 3 SiO 1/2 , HO 1/2 , and R 1 O 1/2 and wherein each occurrence of R 1 is independently a monovalent hydrocarbon group containing from 1 to 30 carbon atoms;
each occurrence of M vi is independently R 2 R 3 3-x SiO 1/2 wherein each occurrence of R 2 is independently a monovalent hydrocarbon group containing from 1 to 30 carbon atoms possessing at least one unsaturated carbon-carbon double bond and each occurrence of R 3 is a monovalent hydrocarbon group containing from 1 to 30 carbon atoms;
each occurrence of Q is independently SiO 4/2 ;
each occurrence of the subscripts a, b, c, f, g and x is independently an integer wherein a is 0 to 200; b is 1 to 202; c is 1 to 100; f is 1 to 100; g is 1 to 150; and x is 1 to 3.
11 . The process of claim 10 wherein each occurrence of M is independently R 1 3 SiO 1/2 , wherein each occurrence of R 1 is a monovalent hydrocarbon group containing from 1 to 6 carbon atoms, R 2 is an monovalent hydrocarbon group containing from 1 to 6 carbon atoms possessing at least one terminal carbon-carbon double bond, R 3 is a monovalent hydrocarbon group containing from 1 to 6 carbon atoms, each a, b, c, f, g and x is an integer, wherein a from 0 to 10; b is from 2 to 15, c is from 2 to 10, f is from 1 to 2, g is from 1 to 4, and most specifically from 1 to 2; and x is 1.
12 . The process of claim 8 wherein the polyorganosiloxane resin is at least one selected from the group consisting of octa(vinyldimethylsiloxy)tetracyclosiloxane, tetra(trimethylsiloxy)tetra(vinyldimethylsiloxy)tetracyclosiloxane, tetra(vinyldimethylsiloxy)silane.
13 . A thermally cured silicone release coating comprising a curing catalyst wherein the catalyst has the formula:
Pt f (M a M vi b Q c ) g
wherein:
each occurrence of M is independently selected from the group consisting of R 1 3 SiO 1/2 , HO 1/2 , and R 1 O 1/2 and wherein each occurrence of R 1 is independently a monovalent hydrocarbon group containing from 1 to 30 carbon atoms;
each occurrence of M vi is independently given by R 2 x R 3 3-x SiO 1/2 wherein each occurrence of R 2 is independently a monovalent hydrocarbon group containing from 1 to 30 carbon atoms possessing at least one unsaturated carbon-carbon double bond and each occurrence of R 3 is a monovalent hydrocarbon group containing from 1 to 30 carbon atoms;
each occurrence of Q is independently given by SiO 4/2 ;
each occurrence of the subscripts a, b, c, f, g and x is independently an integer wherein a is 0 to 200; b is 1 to 202; c is 1 to 100; f is 1 to 100; g is 1 to 150; and x is 1 to 3.