Uticaj vrste drveta i sistema površinske obrade na adheziju premaza

Abstract

U radu je ispitivan uticaj drvne vrste i formulacije premaza u završnom sloju na vrednosti adhezije očvrsnulog filma premaza. Uzorci smrče i hrasta lakirani su 2K poliuretanskim premazom u osnovnim sloju, dok su u završnom sloju korišćene tri vrste premaza: 2K poliuretanski, 2K akril-izocijanatni i 2K alkid-uretanski premaz. Merenje adhezije je vršeno metodom rešetke i metodom pečatnika. Lakirani uzorci hrasta pokazali su od 27,41 do 38,98 % više vrednosti adhezije mereno metodom pečatnika, u odnosu na lakirane uzorke smrče. U poređenju različitih vrsta premaza u završnom sloju najviše vrednosti adhezije, mereno metodom pečatnika, pokazali su 2K akril-izocijanatni (3,72 MPa za uzorke smrče i 5,45 MPa za uzorke hrasta) i 2K alkid-uretanski premaz (3,76 MPa za uzorke smrče i 5,49 MPa za uzorke hrasta). Određena odstupanja u oceni adhezije metodom rešetke u odnosu na vrednosti adhezije dobijene metodom pečatnika pokazala su neophodnost primene više metoda u vrednovanju adhezije očvrsnulog filma premaza na površini drveta.

This paper investigates the impact of wood species and formulation of coating in the top layer to the adhesion of cured coating. The samples of spruce and oak wood were coated with 2K polyurethane coating in the basic layer, while three types of coatings were used in the top layer: 2K polyurethane, 2K acrylic-isocyanate and 2K alkyd-urethane coating. Measurement of adhesion was performed by the cross-cut and pull-off method. The samples of oak wood showed for 27.41 to 38.98% higher values of adhesion measured by pull-off test, compared to the samples of spruce wood. In comparison of different types of coatings in the top layer the highest values of adhesion, measured by pull-off test, showed 2K acrylic-isocyanate coating (3.72 MPa for samples of spruce and 5.45 MPa for samples of oak) and 2K alkyd-urethane coating (3.76 MPa for samples of spruce and 5.49 MPa for samples of oak). Certain disagreement in the assessment of adhesion by cross-cut method compared to the values obtained by pull-off method showed the necessity of applying more than one method for evaluating the adhesion of the cured coating to the wood surface.