Effect of Artificial Weathering and Temperature Cycling On the Adhesion Strength of Waterborne Acrylate Coating Systems Used for Wooden Windows

The adhesion of coatings to wood is important for their long-term performance. In this study, the adhesion strength of water-based acrylate coatings used for wooden windows after exposure to artificial weathering (AW) and temperature cycling (TC) was investigated. The analysis of the adhesion quality of coatings was performed via a pull-off test and failure characteristics. The 3-layered and 4-layered white and brown acrylate dispersions from six different producers were compared and the effect of coating thickness on adhesion strength was investigated. The adhesion strength values proved to be very variable. After AW, the adhesion strength and its variability increased for all the samples. TC had no statistically significant effect on the adhesion strength values. White coating systems were initially characterized by lower adhesion strength, but after AW and TC, they reached higher adhesion strength values than brown ones. The overall highest adhesion after AW and TC was recorded for the coatings based on alkyd-acrylate hybrid basis (Producer 3), while the lowest adhesion variability after AW was measured for one type of tested acrylate coating (Producer 4). The effect of different layering on adhesion strength was not demonstrated in this study.