NOVELTY - A UV-curable coating composition (C1) comprises a urethane-acrylic polymer precursor; an infrared reflective agent; an ultraviolet protective agent; and a photoinitiator. The infrared reflective agent and the ultraviolet protective agent are selected to provide an ultraviolet transmission window which transmits ultraviolet radiation from an ultraviolet source with a frequency that corresponds to the photoinitiator; and where the photoinitiator is activated by ultraviolet light from the ultraviolet light source at a frequency within the ultraviolet transmission window.    USE - As UV-curable coating composition used in composite building material (such as decking, siding, roofing and railing), and in photovoltaic device such as solar cells (claimed).    ADVANTAGE - The composition is environmentally friendly and reduces or eliminates the cost of solvent recovery; and provides protection from the adverse effects associated with long term exposure to ultraviolet radiation and to infrared radiation (heat) from the sun. The use of prior art coating components in conjunction with UV curing systems is problematic, resulting in incomplete curing or low adhesion to the substrate. However, by using the present coating composition, these problems have been overcome by the selection of the IR-reflective agent, UV protective agent, photoinitiator and the UV light source which allow for an efficient curing of the UV cured urethane/acrylic coating. The coating components and the UV light source are selected in combination to allow for the sufficient transmission of a frequency of UV light from the emission source through the entire thickness of the coating to provide for effective UV-curing of the coating. The composition provides a coating thickness of 0.0005-0.003 inches, which gives optimum performance, good adhesion after curing on several substrates, such as decking, siding, roofing and railing, and increases productivity. The use of a UV coating system has the further advantage of reducing manufacturing space and increasing productivity. Typical cure times may be less than a second, allowing for higher line speeds.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a composition (C2) comprising a substrate and the UV-cured coating composition (C1) applied on at least one surface of the substrate.