## 3 Results and Discussion
### Tensile Test of Extruded PVB Filament
The following measurement (Table 4) occurred on a set of PVB filament samples with a diameter of 1.75 mm at a temperature of 150 \({}^{\circ}\)C and a speed of 50 mm.min\({}^{-1}\). \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Test No**} & \multirow{2}{*}{**Temperature**} & **Force Peak** & **Elongation at** & **Elong. Peak** & **Strain Peak** & **Tensile Stress** & **Stress Yield** \\  & & **(N)** & **Break (\%)** & **(mm)** & **(\%)** & **(MPa)** & **(MPa)** \\ \hline
1 & 150 & 90.88 & 37.784 & 5.438 & 5.438 & 0.037 & 37.771 \\ \hline
2 & 150 & 100.88 & 41.941 & 3.012 & 3.012 & 0.025 & 41.916 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Mechanical properties (DIN EN ISO 527-1) [21] of the tested PVB filament with a diameter of 1.75 mm and a temperature of 150 \({}^{\circ}\)C.  
Figure 11: Graphic representation of a tensile test of a 1.75 mm filament with a temperature of 140 \({}^{\circ}\)C.  
The tensile test evaluates the tensile strength of the material. The principle of the test is to stress the test body until the moment the sample breaks (Figure 12). In the tensile test, the test body is clamped in the jaws of the tearing machine and gradually stretched at a constant speed. With increasing deformation (Figure 12), the force required to maintain a continuous displacement speed of the jaws increases. The dependence of stress on the amount of deformation is called the tensile curve, and its shape depends on the type of stressed material. Table 5 shows the results of the tensile test of the PVB material filament at a temperature of 155 \({}^{\circ}\)C. From the point of view of deformation behavior, the most frequently evaluated relative elongation of samples during the tensile test is expressed as a percentage of the original length of the working part of the test specimen. With small deformations of the sample (small values of relative elongation), changes in the cross-section of the sample can be neglected. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Test No** & **Temperature** & \begin{tabular}{c} **Force Peak** \\ **(N)** \\ \end{tabular} & \begin{tabular}{c} **Elongation at** \\ **Break (\%)** \\ \end{tabular} & \begin{tabular}{c} **Elong. Peak** \\ **(mm)** \\ \end{tabular} & \begin{tabular}{c} **Strain Peak** \\ **(\%)** \\ \end{tabular} & \
\begin{tabular}{c} **Tensile Stress** \\ **(MPa)** \\ \end{tabular} &
\begin{tabular}{c} **Stress Yield** \\ **(MPa)** \\ \end{tabular} \\ \hline
3 & 150 & 105.87 & 44.016 & 3.18 & 3.18 & 0.029 & 43.995 \\ \hline
4 & 150 & 108.27 & 45.013 & 50.434 & 50.434 & 0.054 & 44.244 \\ \hline
5 & 150 & 97.28 & 40.444 & 5.67 & 5.67 & 0.017 & 40.415 \\ \hline
6 & 150 & 96.81 & 40.249 & 5.165 & 5.165 & 0.017 & 40.241 \\ \hline \end{tabular}
\end{table} 
Table 4: _Cont._  
Figure 12: Graphical course of a tensile test of a PVB filament with a diameter of 1.75 mm and a temperature of 150 \({}^{\circ}\)C.  
Figure 13 shows a tensile test of PVB filament at a temperature of 155 \({}^{\circ}\)C. The tested samples were subjected to a force stress of 50 mm.min\({}^{-1}\). In principle, the permissible load of the measuring head for force sensing must meet the range for the type of material being tested, which, in the case of polymers, represents a range from approximately 500 N for rubbers to 25 kN for very strong materials [39]. A visible change is in the relative elongation, which, at a temperature of 155 \({}^{\circ}\)C, shows values from 3.096% to 16.725%. The standard specifies a jaw displacement speed of 1 mm/min to calculate the modulus of elasticity in tension (Table 6). At the same time, the stress at elongations of 0.05 and 0.25% is subtracted from the tensile curve. Exclusion of a value from a set of parallel measurements is permitted by the standard only in the following cases:  
* if the body breaks outside the marked working part;
* a tear occurs within 10 mm of the jaw.