Testing method for overall sealing performance of packaging bag

- Aug 14, 2019-

 Packaging bags are widely used in various fields of food packaging and drug packaging. With its advantages of economical packaging cost, easy processing, easy control and easy production, packaging bags have become a very common packaging form in the market. The sealing performance and sealing strength are important indicators of packaging bag quality, which are related to product quality, shelf life and necessary guarantee of product circulation.

Key words: packaging bag, overall tightness, sealing strength, shelf life 

In the food and drug industry, packaging bags are filled with various fields. It is needless to say that they are widely used. Generally, the materials used in packaging bags have excellent printing performance and can play a very good publicity role.As a commodity, the packaging bag is also the guarantee for the circulation of products to prevent damage to products caused by logistics transportation.One of the main functions of the packaging bag is to keep it fresh and ensure its quality, so that the products in the hands of consumers can reach the expected design requirements.However, we may not lack to see various complaints from customers or various claims from customers, which not only makes the enterprise suffer great economic pressure, but also damages the reputation of the enterprise. The root of all this is the unqualified quality of the packaging bags, which causes the enterprise to suffer huge losses. This does not outweigh the benefits. Thus, it can be seen that how to ensure the quality of the packaging bags has also become a favorable safeguard measure to improve the product safety factor and prolong the shelf life of the products.

1. The significance of sealing test for packaging bags

As the losses caused by unqualified packaging bags are heavy and the lessons are profound, how to ensure the quality of packaging bags has become a necessary condition for packaging bag inspection.There are two main reasons for the quality problems of the packaging bag: first, the quality of the packaging bag material is poor, for example, the packaging bag is delaminated due to insufficient interlayer adhesive strength, or the heat-sealing material is not closed properly, and the unstable heat-sealing quality leads to insufficient sealing strength, lax sealing or leakage sealing;Second, improper heat-sealing conditions lead to heat-sealing temperature, heat-sealing time and heat-sealing pressure being the three elements of heat-sealing.In order to ensure the quality of the packaging bag, a more reliable and scientific method is detection, which can not only clearly understand the quality of the packaging bag and the bag breakage rate, but also provide a strong guarantee for the sustainability control of the product quality.

2. Testing Method for Sealing Property of Packaging Bag

2.1 negative pressure test, also known as "bubble method".

Test Principle: Immerse the package to be tested into a vacuum tank filled with water and vacuumize the vacuum tank. When the internal pressure of the package is greater than the external pressure, it will expand and increase. If the seal is not good, there will be blisters. If there is no blisters, then the seal is good. 

Test steps:

This step is introduced by taking LEAK-5001 seal tester produced by Jinan Sike Test Technology Co., Ltd. as an example. The tester adopts TFT true color liquid crystal display and touch screen operation, and the test process is fully automatic without any manual intervention. The test process is as follows:

1.add proper amount of water to the vacuum tank.

2.put the packaging bag into the vacuum tank and cover the sealing cover.

3.start test (touch operation)

4.vacuumize the vacuum tank.

5.Observe whether there is bubble around the packaging bag (bubble emergence indicates leakage and no bubble indicates good sealing)

Seal Tester


                                 Seal Tester

 2.2 positive pressure test.

Test principle:

Positive pressure test is more complicated than negative pressure test, and the test modes mainly include:

Rupture test: gas is filled into the packaging bag until it ruptures, and the sealing strength is evaluated by a larger rupture pressure;

Standard creep: filling a certain pressure of gas into the packaging bag and keeping for a certain time, and judging the creep performance of the packaging bag seal under continuous load through the change of the pressure in the packaging bag.

Creep rupture: gas of a certain pressure is filled into the packaging bag and kept for a certain time, then gas is continuously filled into the packaging bag until it is ruptured, and the pressure resistance of the packaging bag after creep is judged by the pressure change and rupture pressure in the process.

Note: Various tests of the packaging bag under the condition of limited expansion can be simulated through the auxiliary fixture FIXT-PKG-F1203.

Various tests on the sealing strength of three-sided sealing packaging bags can be carried out through the auxiliary fixture FIXT-PKG-F1204.

Test steps:

This step takes PKG-1201 leak tester produced by Jinan Sike Test Technology Co., Ltd. as an example to introduce. The instrument adopts TFT true color liquid crystal display, touch screen operation, and the test process is fully automatic without any manual intervention. The test process is as follows:

1.place the prepared packaging bag on the test rack.

2.test needle inserted into packing bag sealed by rubber pad

3.select test mode and set parameters.

4.click the "test" key, and the test will be carried out automatically until the end.

Leakage Tester

 

Leakage Tester

 3. Conclusion

Packaging bags are widely used in various fields of food packaging and drug packaging. The quality of packaging bags directly affects the food and drug safety and shelf life, and the cost of packaging bags is economic. However, the loss caused by unqualified packaging bags is heavy and the lesson is profound. To ensure the safety and shelf life of packaged products, a more reliable and scientific method is detection. In this way, not only can the detection results be digitized and easy to archive and compare, but also the overall quality of packaging bags can be clearly understood, which is beneficial to tracing the source of the problem, and more favorable is that detection is a powerful guarantee for the sustainable control of product quality.