In this paper, a thermochromic complex was prepared from crystal violet lactone (CVL), bisphenol A (BPA) and tetradecanol. The color-changing temperature of the color-changing compound was found to be 25 °C by orthogonal experiment. Microcapsules coated with a thermochromic compound were added into alkyd resin at different mass concentrations. With the increase in temperature and mass fraction of microcapsules in the coating, the color difference of the coating showed an upward trend. The highest variation in the coating’s color difference occurs when there were 10% microcapsules. When the mass fraction of microcapsules was 15.0~25.0%, there was little change to the gloss of the coating. With the increase in the mass fraction of the coating microcapsules, the hardness of the coating gradually increased. The hardness was at its best when the microcapsule concentration was 25%. When the microcapsule concentration was 20%, the impact resistance of the coating was at its best. The coating had good cold-liquid resistance to acetic acid, ethanol, and NaCl solutions, and there was basically no mark on the coating surface before and after the cold-liquid-resistance test. The addition of microcapsules did not change the chemical composition of the coating, and it improved the performance of the coating. When the microcapsule concentration was 10%, the overall performance of the coating was at its best, which laid the technical foundation for thermochromic coating on the metal surface.

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.

Magnetic carbonyl iron powder (CIP) microcapsules were created by in situ polymerization using melamine resin as the wall material and CIP as the core material. They were mixed with shellac self-repairing microcapsules to prepare dual-functional wood coatings, and the effect of different amounts of CIP microcapsules in the Dulux Waterborne primer on the performance of the primer was investigated. The findings demonstrated that the core-wall ratio had a significant impact on the characteristics of CIP microcapsules. The microcapsule coating rate reached 57.7% when the core-wall ratio was 0.65:1. The maximum reflection loss of CIP microcapsules with the core-wall ratio of 0.70:1 is −10.53 dB. When the addition amount of shellac self-repairing microcapsules is 4.2%, and the additional amount of CIP microcapsules with a core wall ratio of 0.65:1 and 0.70:1 is 3.0%, the coating color difference is the smallest. The number of microcapsules causes a noticeable drop in the coating’s gloss, and the amount of microcapsules causes a small negative change in the coating’s adherence. With an increase in the number of microcapsules, the coating’s hardness, impact resistance, and tensile resistance first rose and subsequently fell. When the content of CIP microcapsules with core-wall ratio of 0.65:1 and 0.70:1 was 9.0%, the hardness, elongation at break and repair rate of the coating reached the best performance. According to a comprehensive analysis, when the content of CIP microcapsules with core-wall ratio of 0.70:1 is 9.0%, the coating has good performance. At this time, the coating has a color difference of 1.83, a glossiness of 19.3, an adhesion of 2 H, a hardness of 3 H, an impact resistance of 17 kg·cm, and a repair rate of 33.3%. This provides a technical basis for the application of multifunctional coatings on wooden substrates.

A mixture of multiwalled carbon nanotubes (CNTs) and carbonyl iron powder (Iron(0) pentacarbonyl, CIP) was used as a core material, and a melamine-formaldehyde resin was used as a wall material to prepare CIP/CNTs microcapsules. A core-wall ratio, content of CNTs in the core material, stirring speed, and reaction time were carried out to explore the most significant factor affecting the coverage rate and yield of microcapsules. The most important factor affecting the preparation of CIP/CNTs microcapsules was the content of CNTs in the core material. The optimized CIP/CNTs microcapsules were mixed with shellac microcapsules, and the optimal ratio was explored by analyzing their optical, mechanical, and electromagnetic wave absorption properties in order to prepare coatings with superior performance. The lower the addition amount of CIP/CNTs microcapsules, the lower the effect on the color difference of the coating. The gloss and adhesion of waterborne wood paint coatings decreased with increasing CIP/CNTs microcapsule addition. The hardness, impact resistance and tensile properties of the coatings showed a tendency of increasing and then decreasing with the addition of CIP/CNTs microcapsules. The surface roughness of the coating basically tended to increase with the increase of CIP/CNTs microcapsule content. When the content of added CNTs in the core material was 3.0% and the content of microcapsules was 9.0%, the coating had the highest elongation at break of 12.4% and the highest repair rate of 34.3%, respectively. The mixed shellac microcapsules and CIP/CNTs microcapsules achieved a theoretical minimum reflection loss of −13.52 dB at 16.2 GHz, and the electromagnetic wave absorption band of less than −5 dB was 15.3 GHz–18.0 GHz. The results provide technical references for the preparation of self-healing composite electromagnetic wave absorption coatings on wood substrates.

An orthogonal experiment was conducted to prepare nine different coatings by changing four influencing factors of shellac microcapsule content, carbonyl iron powder (CIP) content, the content of carbon nanotubes (CNTs), and primer coating thickness. By testing the morphology and performance of the shellac microcapsules, CIP, CNT blended coatings (SCCBC), and using the elongation at tensile failure of the SCCBC as the orthogonal experimental analysis, it was determined that the biggest factor affecting the elongation at tensile failure of SCCBC was the shellac microcapsule content. With the aim of further optimizing the properties of the SCCBC, a single-factor experiment was performed using shellac microcapsule content as the sole variable, and it was determined that the SCCBC exhibited optimal performance when shellac microcapsule content reaches 4.2%. The optical properties of SCCBC were tested, showing that there were minor fluctuations in the glossiness and color difference of the SCCBC. The mechanical properties of SCCBC were tested. The presence of shellac microcapsules can contribute to an improvement of the SCCBC toughness, restraining the formation of microcracks, and have a certain self-healing effect. The electromagnetic wave absorption properties of the mixed powder of shellac microcapsules, CIP and CNTs were tested. The CIP and CNTs can enhance the electromagnetic wave absorption properties of the waterborne coating, but the electromagnetic wave absorption properties were weaker in low-frequency bands. The SCCBC on the surface of fiberboard not only have a self-healing effect, but also have a certain electromagnetic wave absorption function through the mixing of shellac microcapsules, CIP, and CNTs, expanding the application range of waterborne coatings for wood.

Nine sets of orthogonal experimental samples were prepared by examining four factors: shellac microcapsules, carbonyl iron powder (CIP) microcapsules, CIP/ carbon nanotube (CNT) microcapsules, and primer coating thickness. By testing the morphology and performance of the coating and using the fracture elongation of the coating as an orthogonal experimental analysis, the maximum factor affecting the fracture elongation of shellac, CIP, and CIP/CNT microcapsule coatings was determined. The first two factors that had a significant impact on the fracture elongation of the coating were the content of CIP/CNT microcapsules and shellac microcapsules. In order to further optimize the coating performance, important factor experiments were conducted, using the content of CIP/CNT microcapsules and shellac microcapsules as variables. It was found that the coating had the best performance when the content of CIP/CNT microcapsules was 7.0% and the content of shellac microcapsules was 4.0%. The optical properties of coatings with added shellac, CIP, and CIP/CNT microcapsules were tested, and the color difference and glossiness of the coatings showed little change. The mechanical properties of coatings with added shellac, CIP, and CIP/CNT microcapsules were tested. The blending of the three types of microcapsules enhanced the toughness of the coating to a certain extent, and suppressed the generation of micro-cracks, demonstrating a good self-healing effect. The electromagnetic-absorption performance of coatings with added shellac, CIP, and CIP/CNT microcapsules was tested. The blending of shellac, CIP, and CIP/CNT microcapsules exhibited two effective bands of electromagnetic absorption and a good absorption performance at a relatively wide frequency range. The combination of shellac, CIP, and CIP/CNT microcapsules endows the fiberboard surface with self-healing and electromagnetic-absorption functions, while maintaining the original performance of the water-based coating. The results can be used for application of surface coatings on wooden materials with dual functions of self-healing and electromagnetic absorption.