Due to the influence of many factors in the production process of the packaging bag, there may be leakage, pressure penetration or cracks and micropores in the material itself to form small holes connecting the inside and outside. These will have a very adverse effect on the contents of the package, especially in food, pharmaceutical packaging, daily chemical and other industries, where the sealing performance will directly affect the quality of the product. Poor sealing is the main cause of future leakage and corruption.

In order to prevent the air permeability of the packaging bag from affecting the product, it is very necessary to test the air permeability of the packaging bag to ensure the gas barrier properties of the packaging material. From the perspective of the principle of testing the air permeability of packaging bags, the test methods for air permeability of food packaging bags can be divided into two types: differential pressure test and power analysis sensor test.

1. Effect of gas permeation on the quality of food contents

2. Introduction of the main method of air permeability test

The common oxygen barrier test methods of plastic packaging bags are divided into equal pressure method and differential pressure method, and the test chamber of the detection equipment adopting the principle of differential pressure method is divided into upper and lower two, the upper chamber is a high pressure chamber, and the lower chamber is a Low-pressure chamber, the sample is located between two test chambers.

During the test, the sample is clamped between the two test chambers. Firstly, the low-pressure chamber is evacuated, and then the whole system is evacuated. When the specified vacuum degree is reached, the low-pressure chamber is closed, and a certain pressure is filled into the high-pressure chamber. The test gas makes the two test chambers (i.e. both sides of the sample) form a constant pressure difference (adjustable). Under the action of the pressure difference gradient, the test gas will penetrate from the high pressure chamber to the low pressure chamber, and pass The internal pressure is monitored to obtain the various barrier coefficients of the sample.