A coating with thermochromic and photochromic microcapsules can enhance a product’s attractiveness. Different coating processes may affect the performance of coatings. Therefore, the micromorphology, chemical composition, chromatic difference, gloss, hardness, adhesion, impact resistance, roughness, cold liquid resistance, and ultraviolet photooxidation resistance of the surface coating on the metal substrate were assessed by choosing three coating processes. The thermochromic color difference of the coating with photochromic microcapsules in the primer and thermochromic microcapsules in the topcoat changes greatly. When the temperature reached 80 °C, the maximum color difference of the coating was found to be 23.0. The color difference of the coating with the thermochromic microcapsules in the primer and photochromic microcapsules in the topcoat was the most obvious, with a color difference of 71.7. The gloss of the coating mixed with thermochromic microcapsules and photochromic microcapsules was the highest, which was found to be 81.7 GU. The coating gloss of thermochromic microcapsules in the primer and photochromic microcapsules in the topcoat was found to be 15.6. The mechanical property of the coating mixed with thermochromic microcapsules and photochromic microcapsules was the best—the hardness was found to be 2H, the adhesion was found to be level 1, and the impact resistance was found to be 12.5 kg·cm. The mechanical property of the coating prepared by the other two coating sequences was poor. The coating prepared by the three finishing processes on the metal substrate had sufficient cold liquid resistance, and the gloss of the coating before and after the cold liquid resistance changed slightly. By studying the coating process of thermochromic coating and photochromic coating, a technical reference is provided for creating dual-function intelligent coatings.
In this paper, urea-formaldehyde resin microcapsules with shellac resin as core material were prepared by in-situ polymerization. Morphologies of shellac resin microcapsules were characterized by optical microscope (OM) and scanning electron microscope (SEM). Both microcapsules were spherical in shape. The encapsulation property of shellac resin was proved by Fourier transform infrared (FTIR). Shellac resin microcapsules and fluorane microcapsules were added to waterborne primer or topcoat at the same time to prepare waterborne coatings with thermochromic and self-healing dual functions. The effects of microcapsules on optical properties, mechanical properties, self-healing properties, anti-aging performance, and thermoreversible discolouration mechanism of coating films were studied. These results showed that the topcoat with 10.0% fluorane microcapsules and 5.0% shellac resin microcapsules had a better comprehensive performance. At this time, the colour of coating transformed yellow into colourless at 32 °C, and it had a good colour recovery. Shellac resin microcapsules endowed the coating with self-healing performance, and the self-healing rate was 35.9%. The research results provide a reference for the progression of multifunctional wood coatings.
The melamine/rice husk powder-coated shellac microcapsules were prepared by in-situ polymerization with melamine resin mixed with rice husk powder as microcapsule wall material and shellac as microcapsule core material. The effect of the addition amount of microcapsules with different wall material ratios on the performance of wood waterborne primer coating was investigated. The results show that the most important factor affecting the performance of microcapsules is the content of rice husk powder. Through the preparation and analysis of shellac microcapsule primer coating coated with melamine/rice husk powder, when the content of microcapsule powder is 0–6%, it has little effect on the optical properties of wood waterborne primer coating, and the microcapsule with 5.5% rice husk powder has little effect on the color difference of primer coating. The coating hardness increases with the increase of rice husk powder content in wall material. When the rice husk powder content in wall material is more than 5.5%, the coating hardness reaches the best. When the content of microcapsule powder is 3.0–9.0%, the adhesion of the coating is better, and the coating with rice husk powder content of 5.5% in microcapsule wall material has better impact resistance. When the content of rice husk powder was 5.5% and the content of microcapsule powder was 6%, the elongation at break of the primer coating was the highest and the tensile resistance was the best. The composition of wood waterborne primer did not change after adding microcapsule. The water-based primer with microcapsule has better aging resistance. The water-based primer coating with rice husk powder content of 5.5% and the addition amount of 6% had the best comprehensive performance, which lays the technical reference for the toughness and self-repairing of the waterborne wood coatings.
In order to self-repair the cracks of waterborne coatings on Basswood at room temperature, with fluororesin and waterborne coatings embedded in the shell structure of urea formaldehyde (UF) resin, the microcapsules were fabricated via in-situ polymerization, and the effect of microcapsules on the chroma, gloss, mechanics and repair effect for waterborne coatings on wood was discussed. The results indicated that the coating effect was the most significant when the ratio value of the core materials to the shell material of microcapsules in mass was 0.75, and the agglomeration of particles was the least and the surface was the smoothest when the content of microcapsules was 1.0%. It was negative between the gloss of the film and microcapsule content. The ratio value of the core materials to the shell material in mass and the amount of microcapsules had great influence on the film hardness and adhesion, but had little effect on the impact resistance. When the ratio value of the core materials to the shell material of microcapsules in mass was 0.65 and the addition amount was 4.0–10.0%, the aging resistance of the film was improved most significantly. When the ratio value of the core materials to the shell material of microcapsules in mass was 0.65 and the addition amount was 7.0%, the overall properties of topcoat film on Basswood board was the most significant. It is for the application of fluororesin microcapsules possessing self-repairing effect in waterborne coating on Basswood board that a technical groundwork is provided by this study.
In order to explore the applicability of the waterborne coating with self-repairing microcapsules based on the surface of wood boards and specify the optimal range of microcapsule content in the coating, three different kinds of shellac microcapsules (transparent shellac, purple shellac, and yellow shellac) were embedded in a waterborne acrylic coating at 0, 1.5 wt.%, 3.0 wt.%, 4.5 wt.%, 6.0 wt.%, and 7.5 wt.%. The Beli wood (Paraberlinia bifoliolata) boards were then covered with self-repairing coatings to investigate the self-repairing coating’s physical and chemical properties, aging resistance, and scratch repair abilities. The findings demonstrated that the chromatic difference and gloss of surface coatings on Beli wood boards were significantly influenced by the content of microcapsules. The optical characteristics and cold liquid resistance performance of the coating on Beli wood were enhanced when the microcapsule content was 3.0 wt.%. Additionally, the mechanical qualities of the coating with 3.0 wt.% transparent shellac microcapsules on Beli wood surface were better, with an H hardness, grade 2 adhesion, and 8 kg·cm of impact strength. The studies on scratch repairing and aging resistance indicated that microcapsules helped to slow down the coating’s damage and retard aging. After a microcrack appeared, the waterborne coating with microcapsules on Beli wood’s surface had the capacity to repair itself. After aging, the coating with 3.0 wt.% transparent shellac microcapsule on Beli wood boards had a better performance on the comprehensive properties, with a 28.9% light loss rate and a 6 kg·cm impact resistance. It also had a 25.0% repairing rate in scratch width after being damaged for 5 d. This study advances the development of self-healing waterborne coatings on the wood board with shellac microcapsules by examining the effects of shellac in various colors and shellac microcapsule content in waterborne coatings.
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.