We examined the influence of the quality of sanding of particleboards (IP) on adhesion of paper impregnated with melamine resin (MP). 3 different final grain sizes (granulations 36, 80 and 100) were used. The nature of process of making IP produces variable sizes of sand-offs, considering the fact raw thickness of the IP varied also for 2 mm and more. In this concern, 3 thickness types of IP were put to the test: normal, thin and thick; sizes of sand-offs were differentiated according to their thickness. We used the surface soundness test to evaluate the firmness of the surface. The acid test, scratch test and internal pencil test were applied to determine quality of the MP. We used density profile of IP for interpretation of the results. It has been determined that both, raw thickness of the IP and the sanding interval, have greater impact on MP's adhesion to the IP than the grain size itself. Surface soundness increased along the sanding quality up to the point, where the force of the surface soundness was reduced to the value of rough sanding due to the smoothening phenomena and the impression of wooden fibres. The acid test detected a minor difference in hardening of the upper and lower IP's surface, but at the same time the covered IP's surface hardened parallel with the sanding quality. A similar correlation was detected in the scratch test, where the result rose along the sanding quality of the sanded IP's surface. Internal pencil test ascertained that the result of the tests grew parallelly with sanding quality, up to 3rd, the finest sort of sanding. The value of results fell under the value of 1st sanding. The rising density of the IP's peak density covered with MP provided a rising values in the internal pencil test.
|
