Wood coatings: Improving surface durability
Water repellency and weather resistance are key performance metrics for exterior wood coatings. We spoke to Rich Czarnecki, vice president at Micro Powders, about trends and challenges in wood coatings.
What are current trends for wood coatings?
Rich Czarnecki: Formulators are looking for technologies that improve surface durability (scratch, mar, abrasion resistance) in cabinetry, furniture, and flooring. Low-gloss systems continue to be popular. While inorganics dominate the market for general gloss reduction, polymeric additives offer multiple advantages, including viscosity and in-can stability, as well as markedly better resistance to burnishing and polishing. Additionally, the ability to offer unique haptic effects can differentiate and add value to the coating. This trend is especially relevant in flooring, where homeowners are looking for an enhanced “barefoot quality.” New technologies in natural powder additives offer appealing haptics without compromising on durability.
Event tip: more trends in floor coatings will be discussed during PRA’s 12th International Woodcoatings Congress from 8-9 November 2022 in Amsterdam.
What challenges need to be overcome to increase the use of waterborne wood coatings?
Czarnecki: Waterborne IK coatings generally lack the durability of 2K water, solvent, and energy curable coatings. Wax additive nanocomposite technologies can dramatically improve surface durability to compete with traditionally more robust chemistries. Aluminum oxide wax nanocomposites are highly effective at increasing scratch resistance and have been shown to be more efficient when compared to the use of free aluminum oxide. The lighter wax composite particle is more efficient at carrying the denser alumina to the surface during curing, resulting in a higher percent of durable alumina where it is needed. Ceramic nanocomposites can greatly improve abrasion resistance using the same mechanism.
What characteristics are necessary to enhance durability of exterior wood coatings?
Czarnecki: Water repellency and weather resistance are key performance metrics for any exterior wood coating. Novel emulsions based on natural rice bran wax can be used in both high- and low-gloss systems to impart beading (contact angle) superior to conventional paraffin and synthetic wax-based emulsions, while also providing outstanding abrasion resistance and durability. For exterior lower gloss systems, the use of the right polymeric wax additive can outperform silica and other inorganics by delivering a range of mattified surface aesthetics while also enhancing cleanability, and reducing dirt pick-up.
