Effect of Coating Process of Photochromic and Thermochromic Composite Microcapsules on Coating Properties for Basswood

In this paper, photochromic and thermochromic microcapsules were selected. There are three different coating processes: “the primer with the photochromic microcapsules, the topcoat with the thermochromic microcapsules”, “the primer with the thermochromic microcapsules, the topcoat with the photochromic microcapsules”, and “the photochromic and thermochromic microcapsules added into the primer and topcoats” to explore the color-changing effect of the coating on the surface of basswood (Tilia) and the comprehensive properties of the paint film. The optical properties, mechanical properties, cold liquid resistance, and aging resistance of the coating were mainly analyzed. It was concluded that the comprehensive performance of the coating was the best when thermochromic and photochromic microcapsules were mixed on the surface of basswood (Tilia). At a temperature of 80 °C, the color difference reached a maximum of 20.2, and the coating was completely discolored. The color difference of the coating after discoloration under visible light illumination was 56.9. The gloss under the angle of incidence at 60° was 37.4, hardness was 3H, adhesion grade was 1, impact resistance was 10.0 kg·cm, and cold liquid resistance grade was 1. The method of mixing the two microcapsules had better aging resistance. In this paper, the photochromic and thermochromic properties of the coating were studied, and the optimal discoloration of the surface coating of the basswood substrate was solved by different coating processes. This study provided a method for a coating to achieve both photochromic and thermochromic discoloration, broadening the application of discoloration coatings.