Surface properties of oriented strand board coated by electrostatic dry powder spray deposition technique

Abstract

Use of electrostatic powder coating technology for wood-based panels has considerably increased in the last decade. In this study, oriented strand boards (OSB; OSB/2 and OSB/3 grades) were coated with powder coatings using an electrostatic corona spray gun. Epoxy/polyester (hybrid:1/1) coating that is suitable for indoor applications was applied to the surface of OSB specimens (150 g/m2) at three different curing temperatures, 120 °C for 15 min, 140 °C for 10 min, and 160 °C for 10 min using the electrostatic corona gun. The surface properties of the OSB specimens, roughness, wettability, scratch resistance, abrasion resistance, and film thickness were determined. The abrasion resistance and scratch resistance of the coated OSB specimens improved with increasing curing temperature from 120 to 160 °C. The highest mechanical surface strength was obtained from the OSB/3 specimens cured in the infrared oven at 160 °C for 10 min, while the lowest strength was found in the OSB/2 specimens cured in the infrared oven at 120 °C for 15 min. The contact angle values of the coated OSB specimens increased with increasing curing time, while the surface roughness decreased. The curing temperature of the electrostatic powder coating may be a useful indicator to users to obtain better surface quality on the substrate.