The development of the food industry has brought about the vigorous development of the packaging industry. As a kind of food, food has been loved by the public. It is very important for you to understand the characteristics of the self-supporting zipper bags used in food packaging and some special requirements of the plastic bags currently used by EVA. Since food is hard, the thickness of the self-supporting zipper bag and the strength and impact resistance of the material will affect the use of the packaging. In addition, some food free-standing zipper bags are filled with inert gas, so the sealing performance is also very important. The following are the test methods for the tightness and impact resistance of self-supporting zipper bags:

1. Heat sealing test: The sealing strength of the heat seal is verified by heat sealing strength test. If the heat seal strength is not appropriate, it is easy to leak, broken bags and other problems.

2. In order to detect air tightness, parts that are prone to air leakage and pressure relief can be found through air tightness energy (negative pressure method) test.

3. In order to test the impact resistance of the contents, the burst pressure (positive pressure method) test is used to verify, fill the package with gas, and test whether the finished package is broken under the impact of the internal gas, which is used to determine the easy rupture of the finished package Location and compressive strength.

4. The analysis of the gas composition in the package is verified by the performance test of residual oxygen and carbon dioxide in the headspace. The proportion of oxygen, carbon dioxide and nitrogen in the finished packaging can be monitored to determine the sealing performance of the finished packaging, and the proportion of gas in the packaging meets the product quality requirements.

5. For the detection of drop resistance, provide relevant drop resistance tests to further verify whether the bag is damaged when the finished package falls within a certain height.

When the food self-supporting zipper bag is sealed, the sealing part is broken. The reasons are as follows:

1. Reasons for packaging materials

The composite film used in the self-supporting zipper bag has poor peel strength, that is, the composite fastness between the single-layer films in the composite film is poor, and the composite film is prone to delamination. When the heat seal strength of the heat seal is high, under the impact of the packaging or by external force extrusion, the heat seal of the composite film is prone to delamination, resulting in air leakage and rupture near the packaging heat seal. It can be verified by burst pressure (positive pressure method) and peel strength test.

2. Hidden dangers in the production process

If the parameters of the heat sealing equipment are set improperly, it is easy to cause poor heat sealing quality, poor heat sealing (that is, the heat sealing is not tight, easy to separate) or excessive heat sealing (that is, the heat sealing strength is too high, the heat sealing root is broken), which is easy to cause air leakage and heat seal rupture. It can be verified by sealing performance (negative pressure method) and heat seal strength.

Self-supporting zipper bags are widely used in industrial packaging, daily chemical packaging, food packaging, medicine, health, electronics, aerospace, science and technology, military and other fields.