Varnish Adhesion Strength in Natural Aged Wood Material

This study, it is aimed to determine the adhesion strength of varnish layers applied to the surface of fresh and naturally aged wood materials. For this purpose, oak (Quercus Petrea L.), chestnut (Castanea sativa M.) and Scots pine (Pinus sylvestris L.) wood materials were used for each wood species, age period, section direction and varnish type. A total of 360 test samples were prepared and polyurethane, acrylic and water-based varnishes were applied to their surfaces. The adhesion strength of the samples was determined by the pull-off test following TS EN 4624. The statistical analyzes of the data obtained as a result of the experiments were made with the MSTAT-C package software, and the significance values between and within the groups were determined. According to the results of the research, it was determined that the age period did not affect the varnish adhesion strength the highest adhesion strength at the wood species level was obtained in chestnut (3.361 N/mm2), followed by oak (3.191 N/mm2) and Scots pine (2.248 N/mm2). At the varnish type level, the highest adhesion strength was obtained in polyurethane varnish (4.009 N/mm2), followed by acrylic varnish (3.754 N/mm2) and water-based varnish (1.286 N/mm2), respectively. In the section direction comparisons, the adhesion strength was found higher in the tangential direction (3.098 N/mm2) and higher in the radial direction (2.935 N/mm2). In the comparison level of age period-varnish type, the highest was obtained in polyurethane varnish (4.307 N/mm2) applied to the surface of naturally aged wood material, and the lowest was obtained in water-based varnish (1,167 N/mm2) applied to the surface of naturally aged wood material.