Drying stage of coatings on finished wooden elements, in our case doors of kitchen elements, is an important property. It must be high enough that the lowest elements in the stack can stand burden of the elements above. In the Svea Lesna Litija company, using a polyurethane varnish, the problem of stackability, appeared for 2/3 doors on the bottom of a stack. We wanted to find out the reasons for the appearance of this defect. The variable parameters in the laboratory research were: temperature, drying time, air speed and layer thickness of the varnish. The drying stage of the lacquered surface was measured for each combination of the parameters, also on the doors taken from regular production. All measurments were performed according to the DIN 53 150 standard. Every 7 days also the gloss of the doors was measured. The random sampling was preformed 3 times. The results of the research showed that the drying parameters have a major influence to the drying stage of the varnish, and practically none to the gloss of the lacquered surface. We believe that the problem of stackability does not originate from a low drying stage of the coating at the end of a finishing line, but rather in various problems, connected to the properties of the coating.
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