Source: Link Testing Instruments Co.,Ltd.
The raw material of milk is fresh raw milk, so milk is prone to mildew, especially in summer, it must be stored in a cool and low temperature environment. In addition to packaging in the form of plastic or glass bottles and barrels, milk is also commonly packed in plastic bags. This article takes milk PE black and white film packaging as an example to analyze the overall sealing problem of the packaging. Packaging tightness refers to the reliability of the sealing of the packaging bag. If the tightness of the milk packaging is poor, the packaging will leak or break during the circulation and storage process, which will easily cause quality problems such as mildew and poor taste in the milk. It is necessary to ensure that the product has a good sealing performance during the shelf life, so as to reduce the large risks and economic losses that the company will bear due to packaging and sealing problems.
Test method and instrument
The main China domestic testing standards for packaging sealing performance are GB/T 15171-1994 "Test Methods for Sealing Performance of Flexible Packages". The LTY-01 sealing tester developed and produced by Link Testing was selected for the test.
Test principle: By vacuuming the vacuum chamber of the equipment, the sample immersed in the water in the vacuum chamber generates a pressure difference between inside and outside, and checking whether the sample has leaks, so as to judge the sealing performance of the sample; or by checking the vacuum chamber. Apply a vacuum to generate a pressure difference between the inside and outside of the sample, and judge the sealing performance of the sample by observing the sample's shape recovery after the sample expands and releases the vacuum.
Test sample and test process
Test sample: a finished milk plastic packaging bag provided by a food factory.
Experimental procedure:
(1) Immerse the sample in the water in the vacuum chamber.
(2) Put on the sealing cover and set the vacuum pressure parameters and holding time to be reached.
(3) Turn on the gas supply, start vacuuming, and press the start button on the equipment to start the test.
(4) Observe whether continuous bubbles are generated on the packaging surface during the vacuuming process or during the pressure holding process.
Test results and analysis
The sealing performance test results of the three finished packaging bags of milk were: none leaked under -90 KPa.
From the above results, the tested PE black and white film packaging has better overall sealing performance. The LTY-01 leak tester is used to test the sealing performance of the finished product packaging. It is simple to operate, short in time, high in efficiency, reduces the error of human operation, and can accurately reflect the sealing performance of soy sauce. In addition, it is necessary to strengthen the barrier performance, heat sealing strength, tensile strength and pendulum impact energy testing of soy sauce packaging bags.
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