The impact of stain removal and bleaching on the adhesion strength of water-based varnish layers in oak

Abstract

The aim of this study is to determine the performance of water-based varnish adhesion on the process of stain removal, bleaching and impregnation applied to wood surfaces. In order to accomplish this objective, the selected sessile oak (Quercus petreae Mill.) wood samples were firstly contaminated with grease and PVAc glue, after they were cleaned. Then, the wood samples were bleached by using oxalic acid (C2H2O4) and hydrogen peroxide (H2O2). Secondly, preprocessed specimens impregnated with imersol aqua (IA) and wood protective chemicals (WP) and together both these chemicals (IA+WP). Finally, adhesion strength performance of the wood samples were tested after they covered by single component primary resin (SCPR), double component polyurethane modified with acrylic (DCAP) and double component elastic polyurethane (DCEP). The adhesion resistance of varnish layers is determined according to ASTM 4541 principles. As a result, the oil stain removal and the protective chemical applications decreased the adhesion strength on the wood surface of water-based varnish layers. Contrary, the glue stain removal and the C2H2O4 and H2O2 bleaching increased the adhesion strength. Also, it was determined that DCEP applications have the highest value in oak wood samples.