The puncture resistance is a guiding index for evaluating the puncture resistance of packages to sharp hard objects. If the product contains a more sharp hard material, easy to have a strong stretch film puncture effect. The testing methods of packaging puncture resistance in China are mainly based on GB/T 21302 -2007. During the test, a sample with a diameter of 100mm is taken, and then the sample is clamped to the puncture test fixture for testing. The above test is a static test, and can not reflect the stretch film in the winding process of anti-puncture performance.
There are several conditions that directly affect the puncture resistance of the stretch film
1) the stretch film is wrapped directly onto the tray without being stretched
A. The stretch film has almost no puncture problem during the winding process
B. For example 17 micron stretch film, no stretch directly wound on the tray; that is, the thickness of the same wound on the tray is 17 microns. Such a situation will not exist stretch film by sharp object puncture and break the problem
2) the stretch film is stretched to the top
A. The stretch stretched to the top is almost“Zero” resistant to puncture
B. For example 17 micron stretch film, stretching to the back of the top of the thickness is 4 microns. At this point, slight contact with the sharp object will pierce and tear.
3) the tensile thickness of the 17-micron stretch film is 5-6 microns
The tensile ratio is 240%
B. this time the puncture resistance will be better than in the second case
C. Tightening is better than the first case
D. the overall packaging effect is in good condition
Only through the dynamic testing of some important factors in order to test the stretch film’s puncture resistance. Because the wind speed is a dynamic test that directly affects the packaging effect is a major factor. The higher the speed, the higher the secondary tension and the higher the winding tension. If it takes carbon four (Butene) the stretch film as the main material will be easy to be punctured and break when winding the tray bottom and top.
