Two-pack polyurethane surface coating was applied to melamine impregnated paper surfaced particle and MDF panels. Influence of the carrier (particle or MDF panels), PU finish application rate (dry film thickness), number of sanding operations (one or two) and paper roughness (180 or 320 sanding paper granulation) on adhesion, gloss and colour of lacquered surfaces was investigated. It was found out that the investigated properties of a surface system are the most influenced by the application rate - the dry film thickness. In particular, this is the case for gloss and colour and to a lesser extent only for the surface finish adhesion. In general, adhesion strength of the coating was higher on foils on particle boards than on MDF panels. In this case, the important parameter was also roughness (180 or 320 sanding paper granulation). PU coating exhibited better adhesion on foils on particle boards when these were sanded with a coarser paper of 180 granulation. On the other hand, in the case of MDF panels, we could determine the adhesion strength only when they were more smoothly sanded (granulation 320). When a foil on MDFs was sanded with the 180 paper, the adhesion strength test resulted in a cohesive failure of the panel itself and not in an adhesive failure on the substrate - lacquer interface. Both carriers surfaced with paper - particle boards and MDF panels - are quite different regarding the surface finish application. However, when properly prepared, both may be finished with a surface coating and adequate properties of a surface system may be obtained.
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