Causes of damage to plastic bags

The damage of plastic packaging bags in production, transportation and storage is a common quality problem in enterprises. Professional packaging manufacturer lucky time pack has sorted out the most likely reasons for the damage during storage, transportation and vacuum pumping:

Analysis of broken bags during storage and transportation

The items packed in plastic packaging bags will cause the gas pressure in the bag to increase due to the stacking of the items during storage and transportation, which can cause the plastic packaging bags to rupture. Since the location of the rupture is mostly concentrated in the heat sealing position between the materials, the broken bag can be avoided by detecting the heat sealing strength of the heat sealing edge of the packaging, then changing the material, or adjusting the heat sealing process parameters.

The heat sealing strength of the material can be roughly divided into tensile heat sealing strength and expansion heat sealing strength according to the detection method. The tensile heat sealing strength can be detected using a tensile machine.The tensile heat seal strength refers to the ability of the packaging material to resist separation under the same force direction and uniform force. It is particularly suitable for evaluating the opening of plastic packaging bags, but not suitable for solving the problem of broken bags, because the direction and size of the pressure in the bag are uncertain when the bag is broken, and the material near the heat seal may be deformed due to the pressure, resulting in compression and damage of the flexible bag.

The detection of the expansion heat seal strength requires the use of a leak and seal strength tester. When used, it needs to be pressurized into the flexible package, and then the position of the worst strength in the entire package can be detected (not limited to the heat seal location). Since the expansion heat seal strength cannot represent the average strength of the heat seal, there is no correlation between the expansion heat seal strength and the tensile heat seal strength. The expansion heat seal strength is related to the size, geometry and materials of the packaging bag.

Damage analysis of vacuum food package

The reasons for the damage of vacuum packaging bags are mainly analyzed from two aspects of food vacuum packaging design and vacuum packaging materials:

In the design of food vacuum packaging, if the net content or volume of the content exceeds the tolerance range of the flexible packaging material used, during transportation or circulation, a slight external force will cause bag breakage and cracking problems. Generally, as the heat sealing layer of vacuum packing bag, the material thickness should not be less than 50um.

The quality of food vacuum packaging materials causes the problem of cracking in the packaging, which is generally concentrated in the following aspects:

Physical and mechanical properties of food packaging, such as tensile breaking force and elongation at break, puncture resistance, pendulum impact resistance, peel strength, etc., can comprehensively judge the toughness, puncture resistance, impact resistance and other physical machinery of the packaging bag whether the performance meets the requirements of packaging, storage stacking and transportation. (Related to the content, the size of the packaging bag, the transportation route and the packaging form)

The tightness of food packaging, such as burst pressure test, can determine the location of the broken bag and the location of weak mechanical strength. For example, the heat seal strength test can determine whether the heat seal strength meets the requirements of the food content, and determine the location of the poor heat seal and the uniformity of the heat seal effect. For example, the damage of chicken claw vacuum packaging is because when the chicken claw is cut, the bones of some broken claws are sharply cut, and when boiled, the skin shrinks, so the bones are exposed, which is easy to prick the bag during transportation. Therefore, the puncture resistance of the packaging bag should be considered as the focus of the packaging material combination.

The leak and seal strength tester can not only detect the maximum bursting force of the plastic packaging bag, but also test the bursting time of the packaging bag by setting the applied pressure. The stacking structure can be designed according to the test data and the parameters of the heat sealing process can be further adjusted to improve packing effect, or analyze the problems in the packaging structure according to the location of the rupture of the flexible packaging bag.

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