Source：Link Testing Instruments Co.,Ltd
Good sealing performance means that the whole package is intact, and there are no defects on the heat-sealed edge and the surface of the packaging bag that can exchange gas with the outside world. It can ensure that the product does not leak air or liquid during storage, transportation and sales. It is one of the effective ways to prevent product quality problems such as oxidation, deterioration, mold, not crisp, and deliquescence. At present, the testing principles of packaging sealing performance include negative pressure method, vacuum decay method, ultrasonic scanning method, high-voltage discharge method, etc. The negative pressure method has a wide range of applications. The types of packaging that can be tested are not limited by the packaging form, the type of packaged product, the packaging size, etc., and it can intuitively find the location of the test package leaking and the pressure when the leak occurs.
Potato chips are a kind of puffed food with low moisture content and a certain amount of oil. They are sensitive to water vapor and oxygen. If the sealing of the packaging is poor, the potato chips are easy to soften during storage and sales. Therefore, the potato chips packaging bag should have good sealing performance. This paper uses the negative pressure method to test the sealing performance of shrimp cracker packaging.
Test standards and instrument
The test process is based on the standard GB/T 15171-1994 "Soft Package Sealing Performance Test Method", which is applicable to the sealing performance test of sealed soft packages made of various materials.
The test equipment used in this test is the LTY-01 Leak Tester independently developed and produced by Link Testing Instruments Co.,Ltd.
Test principle: The negative pressure method is used to test the sealing performance of the package. The package is placed in the distilled water of the vacuum tank, and the vacuum tank is evacuated to create a certain pressure difference inside and outside the package. If the heat seal part or the bottle mouth of the package is not sealed firmly, or there are pinholes or other types of sealing defects on the surface of the package, the gas inside the package will leak from the weak seal part, which is manifested as continuous bubbles in the water. The pressure at this time is the pressure at which the package leaks. The greater the pressure value when the package leaks, the better its sealing performance.
Test sample and test process
Test sample: This test uses a certain brand of potato chips finished product packaging as the test sample.
Test process:
(1) Pour a certain amount of distilled water into the vacuum tank, immerse the sample in the water in the vacuum tank, and cover it with a sealing cover.
(2) Set the vacuum degree, pressure holding time and other parameter information, turn on the vacuum pump, press the start button on the equipment panel, the test starts, and the vacuum tank is evacuated.
(3) Observe whether there are continuous bubbles on the test surface during the vacuuming or pressure holding process. After the test, check whether there is any liquid infiltration into the package.
Test results and analysis:
When the negative pressure value of the shrimp cracker packaging sample tested in this experiment was -45.9 KPa in the vacuum tank, continuous bubbles were generated at the junction of the upper seal and the back seal, and water penetrated into the package, indicating that the sealing performance of the sample at the junction of the upper seal and the back seal was poor.
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