UV coatings for wooden surfaces

•The objective of the study was fulfilled by developing a sprayable and fast curing coating composition.•Fast curing UV coating composition (10 s curing time) having flow time of 114 s was designed for application on wooden surfaces. The commercial UV coating has curing time of 30 s and flow time 49 s.•The developed UV coating exhibits superior thermal stability then commercial UV & conventional coatings as evident from TGA.•The UV coating was found to be superior in respect to surface resistance than conventional coatings Ultra violet (UV) radiation curing has emerged as a fast and environment friendly curing technique for coating on various surfaces (wood, metals, plastic & stone). Although, there are several UV curable coating formulations available in the international market, but these coatings have quite low viscosity and are not suitable for wooden surfaces as coatings tend to quickly get absorbed in to the porous structure of wood leading to slow curing. There is a need for designing coating formulations which are although sprayable, but have optimum viscosity so as to not get absorbed into the wooden surfaces. Besides, coatings have to have fast curing rate as well, so that while in process of curing they do not get absorbed in to the wood. Generally, UV curable coatings comprise of acrylate based oligomers (epoxy, polyurethane, and polyester), reactive diluents (mono-, di-, or polyfunctional glycidyl ether), photoinitiator (benzyl peroxide, phosphine oxide) and functional additives. These coating compositions are first applied on wooden surface and then exposed to UV radiation for curing. The photoinitiator dissociates on UV exposure to form free radicals, which initiate the polymerization of the oligomers and diluents, leading to the formation of a polymeric crosslinked network on the wooden surface. In the present study, sprayable coating compositions were designed based on epoxy acrylate that get cured within 10 s of UV exposure and exhibit excellent thermal and stain resistance properties.