Effect of Silane Coupling Agent Modification on Properties of Brass Powder-Water-Based Acrylic Coating on Tilia europaea

Fine art coating is usually created by the combination of metal filler and water-based coatings, decorated to the surface of wood structures, furniture, and crafts. However, the durability of the fine art coating is limited by its weak mechanical qualities. In contrast, the metal filler's dispersion and the coating's mechanical properties can be significantly improved by the coupling agent molecule's ability to bind the resin matrix with the metal filler. In this study, a brass powder-water-based acrylic coating was prepared, and three different silane coupling agents, 3-aminopropyltriethoxysilane (KH550), γ-(2,3-epoxypropoxy)propytrimethoxysilane (KH560), and γ-methacryloxypropyltrimethoxysilane (KH570), were used to modify the brass powder filler in orthogonal tests. The artistic effect and optical properties of the modified art coating induced by different proportions of brass powder, silane coupling agents, and pH were compared. The result demonstrated that the amount of brass powder and the kind of coupling agent used had a substantial impact on the coating's optical characteristics. Our results also determined how three different coupling agents affected the water-based coating with varying brass powder contents. The findings indicated that 6% KH570 concentration and pH 5.0 were the ideal conditions for brass powder modification. Better overall performance of the art coating applied to the surface of the Basswood substrates was provided by adding 10% of the modified brass powder into the finish. It had a gloss of 20.0 GU, a color difference of 3.12, a color main wavelength of 590 nm, a hardness of HB, an impact resistance of 4 kg·cm, an adhesion of grade 1, and better liquid resistance and aging resistance. This technical foundation for the creation of wood art coatings promotes the application of art coatings on wood.