INFRARED-REFLECTIVE TWO-PART COATING COMPOSITION
Articles containing thermoplastic, thermoplastic composite or thermoplastic-clad materials are made less susceptible to heat distortion by coating the article with a two-part aqueous coating composition whose first part contains a waterborne active hydrogen-functional latex binder and whose second part contains a water-dispersible polyisocyanate. One or both of the first and second parts contain non-infrared-absorptive colored pigment. A mixture of the first and second parts coated atop a vinyl substrate cures to form a vinyl-adherent, infrared-reflective colored protective film.
1 . A two-part aqueous coating composition whose first part comprises a waterborne active hydrogen-functional latex binder and whose second part comprises a water-dispersible polyisocyanate, wherein one or both of the first and second parts comprise non-infrared-absorptive colored pigment, and wherein a mixture of the first and second parts coated atop a vinyl substrate will cure to form a vinyl-adherent, infrared-reflective colored protective film.
2 . A composition according to claim 1 wherein the pigment comprises a single or mixed metal oxide.
3 . A composition according to claim 1 wherein the mixture contains 8 to 50 wt. % pigment based on total solids.
4 . A composition according to claim 1 wherein the mixture is substantially free of infrared-absorptive colored pigments.
5 . A composition according to claim 1 wherein the mixture contains 20 to 70 wt. % active hydrogen-functional latex binder solids based on total solids.
6 . A composition according to claim 1 wherein the mixture contains 1 to 10 wt. % polyisocyanate based on total solids.
7 . A composition according to claim 1 further comprising a non-hydroxyl-functional resin.
8 . A composition according to claim 1 further comprising cosolvent, plasticizer, catalyst, rheology modifier, surfactant, dispersant or mixture thereof.
9 . A composition according to claim 1 wherein the cured protective film has an L* value less than 60.
10 . A composition according to claim 1 wherein the cured protective film has a total solar reflectance of at least 10 as measured using ASTM E-971-88 (Reapproved 2003).
11 . A composition according to claim 1 wherein the cured protective film reduces susceptibility of infrared-illuminated thermoplastic building components to heat distortion compared to an otherwise similar film made without the non-infrared-absorptive colored pigment.
12 . A coated building component comprising a thermoplastic, thermoplastic-containing or thermoplastic-clad substrate having thereon a wet coating comprising a waterborne mixture of active hydrogen-functional latex binder, water-dispersible polyisocyanate and non-infrared-absorptive colored pigment, which coating will cure to form a substrate-adherent and infrared-reflective colored protective film.
13 . A component according to claim 12 comprising a vinyl substrate.
14 . A component according to claim 12 comprising a polystyrene, thermoplastic polyolefin, acrylonitrile-butadiene-styrene, polycarbonate, nylon or polyester substrate.
15 . A component according to claim 12 comprising a thermoplastic composite substrate.
16 . A component according to claim 12 comprising a fiberglass substrate.
17 . A component according to claim 12 wherein the substrate further comprises thermoset polymer.
18 . A component according to claim 12 wherein the cured protective film is a topcoat.
19 . A component according to claim 12 comprising a window, door, siding, trim, decking, railing, roofing or a wall, floor or ceiling.
20 . A method for coating building components, which method comprises:
a) applying to a thermoplastic, thermoplastic composite or thermoplastic-clad substrate a wet coating comprising a waterborne mixture of active hydrogen-functional latex binder, water-dispersible polyisocyanate and non-infrared-absorptive colored pigment; and
b) curing the coating to form a substrate-adherent and infrared-reflective colored protective film.