## 3 Results and Discussion
### Variation of Mechanical Performances of Water-Based Topcoat Paint Film  
Table 3 shows the change in the hardness of the water-based topcoat paint film. Under the same core-wall ratio, with the content of microcapsules rose, the hardness of the water-based topcoat paint film rose. This is because the microcapsules are a kind of solid powder, and the addition of microcapsules into the water-based topcoat paint film can increase the hardness of the film surface [23; 24]. The hardness of the water-based topcoat paint film with 0.67:1 microcapsules was higher than others. When the content of microcapsules was 0-5.0%, the hardness of the water-based topcoat paint film rose from HB to 2H. When the content increased to 5.0-10.0%, the hardness increased to 3H. When the content continued to increase, the hardness of the water-based topcoat paint film remained unchanged for 3H. In conclusion, when the content of microcapsules was 10.0-15.0%, the hardness of the water-based topcoat paint film was better, and the core-wall ratio of microcapsules was 0.67:1, the hardness of the water-based topcoat paint film was increased more obvious. The test results of the adhesion of water-based topcoat paint film are in Table 4. At the same core-wall ratio, the adhesion of the water-based topcoat paint film declined with the rise in microcapsules content, because the increase in microcapsules leads to the poor interfacial adhesion between the coating and wood [25; 26]. When the core-wall ratio was 0.67:1, the adhesion of the water-based topcoat paint film was the best. When the content of microcapsules was 0-10.0%, the water-based topcoat paint film adhesion was grade 0. When the content increased to 15.0-20.0%, the water-based topcoat paint film adhesion decreased to grade 1. When the content reached 25.0%, the worst adhesion was grade 2. When 0.67:1 and the content of microcapsules was 0-10.0%, the adhesion of the water-based topcoat paint film was the best. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Content of Microcapsules**} & \multicolumn{8}{c}{**Adhesion (Grade)**} \\ \cline{2-7}  & **0.42:1** & **0.50:1** & **0.58:1** & **0.67:1** & **0.75:1** & **0.83:1** & **0.92:1** \\ \hline
5.0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 \\
10.0 & 1 & 1 & 1 & 0 & 1 & 1 \\
15.0 & 1 & 2 & 1 & 1 & 1 & 2 & 2 \\
20.0 & 2 & 2 & 1 & 1 & 2 & 2 & 2 \\
25.0 & 2 & 2 & 2 & 2 & 2 & 3 & 3 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Variation of adhesion of water-based topcoat paint film. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Content of**} & \multicolumn{8}{c}{**Gloss (\%)**} \\ \cline{2-7}  & **0.42:1** & **0.50:1** & **0.58:1** & **0.67:1** & **0.75:1** & **0.83:1** & **0.92:1** \\ \hline
0 & 29.4 \(\pm\) 0.8 & 29.4 \(\pm\) 0.8 & 29.4 \(\pm\) 0.8 & 29.4 \(\pm\) 0.8 & 29.4 \(\pm\) 0.8 & 29.4 \(\pm\) 0.8 & 29.4 \(\pm\) 0.8 \\
5.0 & 15.3 \(\pm\) 0.8 & 8.9 \(\pm\) 0.2 & 10.2 \(\pm\) 0.2 & 17.9 \(\pm\) 0.7 & 13.6 \(\pm\) 0.6 & 11.2 \(\pm\) 0.9 & 11.8 \(\pm\) 0.3 \\
10.0 & 9.4 \(\pm\) 0.1 & 7.1 \(\pm\) 0.1 & 9.1 \(\pm\) 0.1 & 11.9 \(\pm\) 0.2 & 10.4 \(\pm\) 0.2 & 8.6 \(\pm\) 0.2 & 10.6 \(\pm\) 0.1 \\
15.0 & 4.0 \(\pm\) 0.1 & 4.6 \(\pm\) 0.1 & 7.3 \(\pm\) 0.2 & 6.7 \(\pm\) 0.1 & 5.2 \(\pm\) 0.1 & 3.4 \(\pm\) 0.1 & 5.0 \(\pm\) 0.1 \\
20.0 & 2.6 & 3.6 \(\pm\) 0.1 & 2.9 \(\pm\) 0.1 & 5.5 & 3.2 & 2.8 \(\pm\) 0.1 & 3.3 \(\pm\) 0.1 \\
25.0 & 2.4 \(\pm\) 0.1 & 3.3 & 2.3 & 3.2 & 2.1 \(\pm\) 0.1 & 2.1 \(\pm\) 0.1 & 3.2 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Variation of gloss of water-based topcoat paint film.