UV-curable self-matting waterborne polyurethane acrylate coatingviaself-wrinkled surface during curing in open-air

Abstract

UV-curable self-matting coatings with self-wrinkled surface during UV-curing in open-air based on the balance between polymerization and oxygen inhibition rates.

Effect of Photoinitiator Concentration and Film Thickness on the Properties of UV-Curable Self-Matting Coating for Wood-Based Panels

“…The 172 nm UV penetration is not strong enough to penetrate the wet film completely, only a gradient curing film is generated on the surface, as shown in Figure 3(Aa,Ab). As the curing process progresses, pressure stress builds up inside the system due to the varying degrees of curing According to previous research, we also found that the gloss value of films at 85 • geometry increased with increasing PI concentration, which was related to the morphology of surface wrinkles of the film [15]. The mechanism of preparing the self-matting coating using dual-UV curing technology is illustrated in Figure 3A.…”

“…Thus, these results could offer valuable insights into the practical applications of wood coatings. According to previous research, we also found that the gloss value of films at 85° geometry increased with increasing PI concentration, which was related to the morphology of surface wrinkles of the film [15]. The mechanism of preparing the self-matting coating using dual-UV curing technology is illustrated in Figure 3A.…”

“…The test results were determined by assessing the hardness of the pencil when no significant difference in the reflected light between the area crossed by the pencil and the surrounding area was observed. The film s abrasion resistance is better than that of previous research [15], mainly due to the dual-UV curing process used in this study, which significantly improved the acrylate conversion from 75.1% to 93%. Additionally, high-hardness SiO2 was added as a filler, enhancing the wear resistance of the film [58].…”

“…Typically, three strategies are employed for preparing matte coatings, including adding matting agents to the coatings, developing self-matting resins or phaseseparated hybrid systems [11,12], and the physical extinction of the coating surface by different curing techniques and equipment (such as electron beam curing and vacuum UV curing), with the ultimate goal of achieving a rough surface and low gloss [13,14]. In the previous study, we found that the third method mainly utilizes the instability of the coating film during the curing process, resulting in wrinkles on the surface of the coating film [15]. Based on existing research, there are two typical methods for this approach.…”

“…The rigid skin layer develops wrinkles due to the transfer of interlayer pressure. The second method utilizes the equilibrium conditions of the oxygen inhibition rate and polymerization rate during UV curing in the ambient air [15]. During this UV curing process, the surface of the liquid coating is significantly affected by oxygen inhibition, while the lower part of the surface is less affected.…”