First, plastic packaging bags are easily damaged in the following situations during production, transportation and storage:
1. Damage caused by automatic packaging process: In automatic packaging, the filler will have a strong impact on the bottom of the bag. If the bottom of the bag cannot withstand the impact, the bottom of the bag will crack;
2. Damaged during transportation and product stacking, plastic packaging bags cannot withstand the increase in internal pressure caused by product stacking pressure, friction during transportation, etc., and the bag ruptures;
3. Damage to the packaging bag during the vacuuming process: the thickness of the packaging bag is too thin, the packaging bag shrinks when vacuuming, the content has hard objects, the needle corner or the vacuum machine has hard objects (dirty) pierce the packaging bag and cause damage;
4. Damage caused by insufficient pressure resistance and high temperature resistance of plastic packaging bags in vacuum or high temperature and high pressure:
5. Due to the low temperature of the frozen plastic packaging bag, the packaging bag becomes hard and brittle, resulting in poor freeze crack resistance and puncture resistance, which may cause the packaging bag to break.
Second, the reasons for the damage of plastic packaging bags during storage and transportation:
During storage and transportation of items packed in plastic packaging bags, the stacking of the items will increase the air pressure in the bag, which will cause the plastic packaging bag to rupture. Because the location of the crack is mostly concentrated in the heat sealing position between the materials, that is, the part where the heat sealing of the plastic packaging bag is relatively weak, the broken bag packaging edge can be detected by detecting the heat sealing strength of the heat sealing, and then the material is changed or the heat sealing process parameters are adjusted .
The heat-sealing strength of materials can be roughly divided into tensile heat-sealing strength and expansion heat-sealing strength according to the testing method. The tensile testing machine can be used to test the tensile heat seal strength, that is, the ability of the packaging material to resist separation under the same force direction and uniform force value. It is especially suitable for the assessment of the opening of plastic packaging bags, but it is not suitable for solving the problem of plastic packaging bag damage, because the direction and size of the pressure in the bag that cause the broken bag are uncertain, and the close heat-seal material may be deformed due to partial pressure, resulting in plastic packaging bags Crushed.