Silicone coating composition containing surface sheen modifier
There is provided herein an opaque one-part room temperature vulcanizing silicone polymer composition comprising: (a) a silanol-terminated diorganopolysiloxane, (b) an opaque reinforcing filler; (c) a polyalkoxysilane crosslinking agent; (d) a condensation cure catalyst; (e) an organo-functional alkoxy silane adhesion promoter; and, (f) a cyclic siloxane. There is also provided a method for the continuous production of such a silicone polymer composition, and a paint containing such a silicone polymer composition.
1. A paint selected from the group consisting of an acrylic paint, an acryl-silicone paint, a polyester paint, a urethane paint, a fluoride paint, a vinyl chloride paint, a latex paint, an acrylic-latex paint, and an alkyl paint, comprising an opaque one-part room temperature vulcanizing silicone polymer composition consisting essentially of:
(a) a silanol-terminated diorganopolysiloxane of the general formula (1):
wherein R 1 and R 2 are independently monovalent hydrocarbon radicals containing up to about 12 carbon atoms, and the subscript n is of such a value that the viscosity of the silanol-terminated diorganopolysiloxane is from 50 to 1,000,000 cps;
(b) an opaque reinforcing filler which is selected from the group consisting of untreated or stearic acid-treated ground, precipitated or colloidal calcium carbonates, alumina, aluminum hydroxide, titanium hydroxide, clays, diatomaceous earth, iron oxide, carbon black, graphite and combinations thereof;
(c) a polyalkoxysilane crosslinking agent of the general formula (2):
(R 1 O) 4-a (R 2 ) a Si (2)
wherein R 1 and R 2 are as defined and the subscript a is 0 or 1;
(d) a condensation cure catalyst;
(e) an organo-functional alkoxy silane adhesion promoter of the general formula (6)
(R 10 O) 3-a (R 11 ) a SiX (6)
wherein R 10 and R 11 are independently monovalent hydrocarbon radicals containing up to about 12 carbon atoms, and subscript a is as defined, and X is an organo group of up to 12 carbon atoms; and,
(f) a cyclic siloxane of the general formula (7):
wherein R 12 and R 13 are independently linear or branched alkyl radicals of from 1 to 4 carbon atoms, and the subscript x is from about 3 to about 10; and, wherein the composition is in the absence of silica-based matting agents, and wherein the silicone polymer composition is present in an amount of from about 1 to about 50 weight percent of the paint composition.
2. The paint of claim 1 wherein R 1 and R 2 of the silanol-terminated polydimethylsiloxane (a) of the general formula (I) are each independently methyl or ethyl and the subscript n is from about 300 to about 4,000.
3. The paint of claim 1 wherein R 1 of the polyalkoxysilane crosslinking agent (c) of the general formula (2) is a linear or branched hydrocarbon radical containing up to about 4 carbon atoms and the subscript a is 0.
4. The paint of claim 1 wherein the condensation cure catalyst (d) is of the general formula (3):
wherein Me is a metal selected from the group consisting of lead, tin, zirconium, antimony, iron, cadmium, barium, manganese, zinc, cobalt, nickel, aluminum, gallium, geranium and titanium, the subscripts is from about 0.7 to about 1.3, and the subscript t is from 0.8 to 1.2, R 7 is a divalent hydrocarbon radical containing from 2 to about 20 carbon atoms, optionally substituted with a hydrocarbon group containing up to 8 carbon atoms, R 3 is hydrogen or an organic radical selected from the group consisting of hydrocarbyl, halohydrocarbyl and acyl each containing up to 8 carbon atoms, R 4 is the same as R 3 or part of a cyclic hydrocarbon group formed by a bond to a carbon atom of the adjacent R 3 and/or R 5 groups wherein the cyclic hydrocarbon group contains up to 12 carbon atoms, and optionally substituted with one or more functional groups selected from the group consisting of chloro, nitro, ester, cyano, and carboxy ester substituents, R 5 is defined the same as R 3 ; R 6 is a monovalent organic radical selected from the group consisting of hydrocarbyl, halohydrocarbyl and ether containing up to 60 carbon atoms, cyanoalkyl containing up to 12 carbon atoms, amino and polyether groups of the formula (C q H 2q O) v R 8 , where q is from 2 to 4, and v is from 1 to 20, and R 8 is a monovalent hydrocarbon radical of from 1 to 30 carbon atoms.
5. The paint of claim 1 wherein the condensation cure catalyst (d) is of the general formula (4):
wherein R 9 is methyl or —OC 2 H 5 .
6. The paint of claim 1 wherein the condensation cure catalyst (d) is of the formula (5):
7. The paint of claim 1 wherein the organo-functional alkoxy silane adhesion promoter (e) of the general formula (6) is selected from the group consisting of methacryloxypropyltrimethoxysilane, glycidoxypropylethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxyethyltrimethoxysilane, β-(3,4-epoxycyclohexyl)propyltrimethoxysilane, β-(3,4-epoxycyclohexyl) ethylmethyldimethoxysilane, isocyanatopropyltriethoxysilane, isocyanatopropylmethyldimethoxysilane, β-cyanoethyltrimethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, n-2-aminoethyl-3-aminopropyltrimethoxysilane, n-2-aminoethyl-3-aminopropyltriethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, aminopropyltrimethoxysilane, N-Phenyl-γ-aminopropyltrimethoxysilane, triaminofunctionaltrimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropylmethyldiethoxysilane, methylaminopropyltrimethoxysilane and combinations thereof.
8. The paint of claim 1 wherein the cyclic siloxane of the general formula (7) is selected from the group consisting of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, dodecamethylcyclohexasiloxane and combinations thereof.
9. The paint of claim 1 further comprising at least one of a pigment, plasticizer, thixotrope, antioxidant, ultraviolet stabilizer, moisture scavenger, surfactant, solvent or biocide.
10. The paint of claim 1 which has a VOC level not exceeding about 50 gm/L.
11. The paint of claim 1 having a gloss level of from about 4 to about 80 as measured by a 60° angle KSM MG-6-S1 gloss meter.
12. The paint of claim 1 having a semi-gloss, satin or matte appearance.
13. The paint of claim 1 having a gloss level of from about 15 to about 70 as measured by a 60° angle KSM MG-6-S1 gloss meter.
14. The paint of claim 1 wherein the paint is an exterior silicone trim paint.
15. A method for the continuous production of the paint of claim 1 consisting essentially of:
(I) mixing a silanol-terminated organopolysiloxane (a) and reinforcing filler (b) in a densifier;
(II) adding the mixed contents of the densifier to an extruder apparatus;
(III) adding the polyalkoxysilane crosslinking agent (c), condensation cure catalyst (d), organo-functional alkoxy silane adhesion promoter (e) and cyclic siloxane (f) to the extruder apparatus at a point downstream of the addition step (II);
(IV) extruding the contents of step (III); and,
(V) applying a de-airing vacuum at a point following step (III) but prior to step (IV) or at a point during and/or after step (IV) to produce the silicone polymer composition of claim 1 ,
wherein steps (I)-(V) are conducted for a period of time sufficient to repeat steps (I)-(V) at least twice, and adding the silicone polymer composition to a paint composition to form a paint composition comprising the silicone polymer composition.
16. The paint produced by the method of claim 15 , wherein the paint has a VOC level not exceeding about 50 g/L.
17. The method of claim 15 wherein the paint composition has a gloss appearance of semi-gloss, satin or matte.
18. The method of claim 15 wherein the paint composition has a gloss level of from about 4 to about 80 as measured by a 60° angle KSM MG-6-S1 gloss meter.
19. The paint of claim 1 wherein the paint is a silicone exterior paint.