UV technology has been used in wood coatings since the late seventies. Until now all of these
applications have been based on 100% UV curable products, formulated mainly for roller coater
application, so it was only possible to coat flat panels. After many developments, UV technology now offers a broad range of 100% UV curable resins and reactive diluents and has become the preferred technology for industrial parquet coatings, providing excellent adhesion and abrasion performance. The furniture industry needs to coat flat panels, slightly profiled pieces (for example doors) and 3-D pieces such as chairs or assembled furniture. Spray, curtain or vacuum coaters are better suited for these applications than roller coater. Unfortunately, the low viscosity 100% UV curable binders do not perform well in spray formulations. Many attempts have been made to cut the viscosity with organic solvents with some success, however, a major advantage of UV technology was lost i.e. very low VOC emission. During the nineties, UV curable polyurethane dispersions in water (UV PUD’s) were developed. PVC flooring was the first industrial application. The flexibility, adhesion and stain resistance of these coatings made this new technology very successful. UV PUD’s open up applications (e.g. spray) which were difficult accessible (due to viscosity) in the past with 100% UV technology. Nowadays a broad range of UV PUD’s is available: for primer (adhesion and wood wetting) and for topcoats (good appearance and excellent stain resistance). Binders with good outdoor performance and binders for pigmented and high scratch resistance coatings have recently been developed (see further).