Food packaging bag sealing test method - Database & Sql Blog Articles

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Sealing performance refers to the reliability of the package seal.

Sealing performance is an important weight for product quality.

In the storage of food packaging bags, there are many reasons for the deterioration of the contents. Among them, the most common reason is the poor barrier properties of the film and the tightness of the packaging bag.

In this regard,

When designing the package, the performance and thickness of each layer of material should be fully considered to obtain sufficient barrier properties.

Sealability is the property of the bag to prevent other substances from entering or the contents from escaping. In the production process of food packaging bags, due to the large number of production links, heat sealing leaking, pressing or cracks and micropores of the material itself may be generated, and small holes or weak points of internal and external communication may be formed. These will have a very negative impact on food, directly affecting the quality of the product. In particular, the small holes cause the food part to be directly exposed to the air, which loses the meaning of keeping the bag fresh.

Therefore, it is also necessary to do the relevant sealing test to reduce the loss and improve the reputation of the product.

Jinan Hengpin Sealing Tester will help you solve all problems.

Take the milk bag as an example. If it leaks, you can find the leak by hand. But for solid foods such as instant noodles and biscuits, how do you find leaks in food packaging bags?

Water decompression method (vacuum method)

The instant noodles are usually immersed in water to evacuate the outside world. If there is a leak in the bag, if there is a bubble like the tire leaks, the leak can be clearly found.

It is known that the most common means of determining sealing performance is a test apparatus with a vacuum.

Test device

According to GB/T15171-94 "Test Method for Sealing Performance of Flexible Packages", the vacuum test device shall include the following parts:

1. Vacuum chamber: consists of a vacuum container and a sealing cover made of transparent material that can withstand a pressure of up to 100 kPa.

A vacuum container is used to hold the test liquid and the test sample; a sealing cover is used to seal the vacuum chamber. When vacuuming, the sealing cover should ensure the tightness of the vacuum chamber.

2. Specimen fixture: used to fix the specimen in the test liquid in the vacuum chamber. The material and shape shall not affect the performance and test observation of the specimen. It is best to choose a transparent material.

3. Pipe: It includes a gas source connecting pipe, a vacuum pipe connected to the vacuum source, and an exhaust pipe connected to the atmosphere. Both should be equipped with a valve to control opening and closing.

4. Vacuum gauge: used to measure the vacuum degree in the vacuum chamber, the accuracy of which is not less than 1.5;

5. Control device: including vacuum switch, vacuum adjustment device, intake valve, etc.

Color printing factory test practice

In flexible packaging inspection applications, a vacuum generator principle detection device is generally used.

The vacuum generator is used to make the positive pressure of compressed air into a stable air source by using the jet principle, which can avoid the disadvantages of pressure pulsation and high impurity content caused by vacuum pump vacuum pumping.

Jinan Hengpin

For example, the leak tester (vacuum generator) uses the following steps in the water decompression test:

1. Put an appropriate amount of tap water in the vacuum chamber and place the sealed sample bag in the vacuum chamber.

2. Cover the sealing cover of the vacuum chamber. The sealing cover is pressed with the pressure plate to press the sample bag in the water. Turn on the power switch and turn the pressure switch to adjust the knob to vacuum the vacuum chamber. The time and vacuum can be controlled at will.

The adjusted vacuum value is determined according to the characteristics of the sample (such as the packaging materials used, the sealing conditions, etc.) or the relevant product standards. However, the sample may not be cracked or cracked at the seal due to excessive pressure difference between the inside and outside of the sample.

3. Observe the leakage of the sample during vacuuming and vacuum maintenance, as it has five consecutive bubbles. A single isolated bubble may be a gas attached to the outside of the package and is not considered a sample leak.

4. Close the vacuum knob, open the intake pipe valve, open the vacuum chamber to the atmosphere, open the sealing cover, and take out the sample bag.

If the sample does not infiltrate during continuous vacuum generation and vacuum sealing during vacuuming and vacuum maintenance, the sample passes, otherwise it is unqualified.

Use other methods, require the bag to leak under the set test conditions, or no test liquid leaks out, or quickly restore the pressure in the vacuum chamber. If the sample can return to the original shape, it is judged as unqualified.