## 3 Results  
### Single-Factor Experiment  
#### 3.1.1 Determination of Peeling Strength  
The heat sealing strength of the seedling belt can be determined by the force required to separate all bonding points on the belt. After heat sealing, the seedling belt samples are mounted on a testing machine to measure the bonding point peeling force. Before testing, the samples must be allowed to cool to room temperature. During the test, two fixtures of the testing machine secure the same end of both layers of film, which are then unfolded at the bonding points to form a 180\({}^{\circ}\) angle, as shown in Figure 11. Under the tensile force of the testing machine, the bonding points on the two layers of film are gradually separated. Due to the structural distribution of the bonding points on the seedling belt, the testing machine simultaneously separates two bonding points during belt peeling. When all bonding points on the belt have been separated, the maximum force measured is the heat sealing strength of the seedling belt. In the preliminary experiments, variations in the levels of each factor had a certain impact on the peel strength. To determine the influence of each factor on the peel strength, we first conducted experimental studies on samples at temperatures of 135 \({}^{\circ}\)C, 140 \({}^{\circ}\)C, 145 \({}^{\circ}\)C, 150 \({}^{\circ}\)C, and 155 \({}^{\circ}\)C. According to the requirements, the time and pressure were  
Figure 11: (**a**) Universal testing machine; (**b**) test samples awaiting examination. Figure 10: Heat sealing of seedling belt. set at 1.2 s and 0.4 MPa, respectively. The heat-sealed samples were subjected to peel strength tests, with each level tested five times and the average taken as the result. The experimental results are shown in Table 2 and Figure 12a. The results indicate that the peel strength increases significantly with rising temperature. Test serial numbers 1-5 in Table 2 show that, at 140 \({}^{\circ}\)C, the average peel strength of the samples was 12.45 N, which is close to the target value of 13.2 N. Next, keeping the temperature and pressure at 145 \({}^{\circ}\)C and 0.4 MPa, we tested the heat sealing time at five levels: 1 s, 1.1 s, 1.2 s, 1.3 s, and 1.4 s. The experimental steps and methods were the same as before. The results, shown in Table 2 and Figure 12b, also indicate that with constant temperature and pressure, longer sealing times result in greater peel strength. Data from test serial numbers 6-10 in Table 2 show that, when the time was 1.1 s, the average peel strength was 14.45 N, closest to the target value. The influence curve in Figure 12b similarly demonstrates that the heat sealing time has a significant effect on the peel strength. Finally, with the temperature and time set at 145 \({}^{\circ}\)C and 1.2 s, we varied the pressure for testing at five levels: 0.3 MPa, 0.35 MPa, 0.4 MPa, 0.45 MPa, and 0.5 MPa. The experimental steps and methods remained the same. The results are shown in Table 2 and Figure 12c. Data from test serial numbers 11-15 in Table 2 indicate that, under constant temperature and time, the average peel strength was 15.45 N when the pressure was 0.35 MPa, which is closest to the target value. Figure 12c shows that, as the pressure increases, the peel strength also increases. Compared with Figure 12a,b, the upward trend of the curve is more gradual, and the curve levels off when the pressure reaches 0.45 MPa. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**No. ** & **Temperature/\({}^{\circ}\)C** & **Time/s** & **Pressure/MPa** & **Peel Strength/N** & **Variance/S\({}^{2}\)** \\ \hline
1 & 135 & 1.2 & 0.4 & 8.24 & 0.2674 \\
2 & 140 & 1.2 & 0.4 & 12.45 & 0.3331 \\
3 & 145 & 1.2 & 0.4 & 18.73 & 0.4306 \\
4 & 150 &  
Considering the experimental results of all factors, the order of significance affecting the peel strength is the temperature, time, and pressure.