Wood conversion companies seeking higher end finish performance such as in consumer cabinetry, furniture and flooring have embraced waterborne (WB) energy curable coating technology as a preferred coating method. WB energy curing gives an appearance similar to solvent based coatings but, eliminates the plastic look of 100% solid ultraviolet (UV) coatings and provides superior solvent and impact resistance. Although advancements in microwave drying have made WB energy curing more attractive to end users, the need to thermally dry sensitive substrates still remains a limiting factor in the proliferation of WB UV/electron beam (EB) energy curing in wood and other sensitive renewable substrate conversion applications. Thermal drying is a challenge for any heat sensitive, resinous and oily woods such as pine, fir, spruce and mahogany. When resinous woods become too hot, the resins or pitch come to the surface or "bleed," causing problems with coating adhesion and discoloration." As an alternative to drying waterborne wood coating systems with conventional direct heat methods, this paper and presentation focus on the potential of ultrasonic acoustically assisted indirect airborne drying. Lower energy consumption, increased output and smaller production footprints for inline wood coating applications in addition to the ability to dry heat sensitive substrates at near ambient room temperature are all benefits of ultrasonic acoustic drying technology. Proof of concept test data on accelerated drying times at near room temperature, gloss, and adhesion performance generated using commercially available ultrasonic acoustic heat and mass transfer equipment are reviewed in this document.
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