Nanosized curing catalyst via nano-templated plasma PVD for attaining superior low-cure powder coating films

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The addition of curing catalysts into powder coating is a key method to fabricate low-temperature curing powder coating for reducing energy consumption and expanding its applications to heat-sensitive substrates. However, the heterogeneous dispersion of the unmodified catalysts in powder coatings results in inconsistent catalysis of resin crosslinking, thus leading to compromised surface smoothness and gloss. Utilizing nanosized catalysts is an efficient solution to such problems. In this paper, we propose a nano-templated dielectric barrier discharge (DBD) plasma-assisted physical vapor deposition (PVD) strategy to fabricate the nanosized catalysts. The curing catalyst, 2-ethylimidazole (2-elm), is successfully vaporized and deposited on nano-carrier SiO2 (SiO2-NPs) in the DBD plasma reactor at atmospheric pressure, producing 2-elm@SiO2-NPs. The mechanical strength and chemical resistance of finishes of powder coating incorporated with the 2-elm@SiO2-NPs remained at low curing temperature (170 °C for 15 min) and fast curing condition (190 °C for 8 min). In addition, their surface qualities are comparable to that of the original powder coating, with up to 100 % gloss retention, successfully eliminating the issue of more than 25 % gloss attenuation of the powder coating with unmodified 2-elm. This study provides an effective, solvent-free strategy for fabricating nanosized curing catalysts and achieving high-quality film finishes.