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    Home > Active Ingredient News > Drugs Articles > Test method for sealing performance of black and white film packaging bag of liquid milk PE

    Test method for sealing performance of black and white film packaging bag of liquid milk PE

    • Last Update: 2014-11-05
    • Source: Internet
    • Author: User
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    Abstract: in the process of storage and shelf life, liquid milk products are prone to quality problems such as bag expansion deterioration or seal leakage Most of these problems are caused by poor sealing performance In addition to obvious liquid milk leakage, sealing problems such as bag expansion deterioration that are not easy to be observed in the early stage need to be detected by sealing tester This paper introduces in detail the importance of the negative pressure sealing tester in the sealing test of packaging parts, and details the testing principle and steps of the negative pressure sealing tester, which can provide customers with references about the sealing of packaging products Key words: liquid milk, black and white film, package, finished product packaging, sealing effect, sealing tightness, sealing tester, negative pressure method, leakage, air leakage test significance: liquid milk is an essential nutritional food in public life, and the consumption of corresponding products in the market is rapid Because a large amount of liquid milk is needed every day, consumers often buy a large number of liquid milk at one time, so it is a problem that every dairy enterprise is eager to break through to extend the shelf life of liquid milk on the basis of ensuring food safety as much as possible In addition to sufficient sterilization of milk and selection of high barrier packaging materials, the measures to extend the shelf life of liquid milk are very important for quality control If the sealing of the liquid milk packaging bag is not sealed, it is easy to cause the outside air to enter the packaging slowly, which will cause the milk to deteriorate and the bag to expand, and then the liquid milk will leak from the sealing place Therefore, the "tightness" test is the key monitoring index for the quality of liquid milk packaging PE black-and-white film is the main material for filling liquid milk In the process of production, storage, transportation and shelf life, there are often quality problems of leakage or bag expansion, most of which are caused by the loose sealing of the packaging bag The reason for the unsealed sealing of liquid milk products is that the parameters of the heat sealing equipment used for sealing the mouth are not adjusted properly, resulting in the poor heat sealing For example, if the temperature or pressure of the heat seal is too low, the seal will not be tightly contacted, and it is easy to leak or break the seal; if the temperature or pressure of the heat seal is too high, it will easily leak or even break the seal root In addition, if the cold sealing adhesive has poor adhesion or the cold sealing pressure is low, it is easy to cause poor sealing Therefore, it is necessary to select a reasonable sealing test equipment for packaging sealing test Test method: vacuum equipment with negative pressure method is used for sealing test of finished product packaging, that is, the finished product packaging is put into the sealed tank with distilled water, and then vacuum pump is used to extract the gas in the tank, so as to ensure that the negative pressure value in the tank increases gradually, and the finished product packaging expands gradually If there are parts with poor sealing, bubbles will appear under a certain pressure, or even liquid milk will escape At present, the domestic test of the sealing performance of soft package mostly follows the national standard GB / T 15171-94 test method for sealing performance of soft package, which is mainly for the soft package products made of various materials We will use mfy-01 sealing tester developed by Labthink Languang company to test the sealing performance of PE black and white film packaging bags for fresh milk in combination with the above standards 1 The mfy-01 sealing tester of Labthink blue light, with a vacuum degree of 0-90 kPa, can be customized according to the size of the package to be tested The commonly used sizes are Φ 270 mm × 210 mm (H), Φ 360 mm × 585 mm (H), Φ 460 mm × 330 mm (H) The instrument system adopts digital preset test vacuum degree and vacuum holding time to ensure the accuracy of test data; adopts automatic constant pressure air supply to further ensure that the test can be carried out under the preset vacuum conditions; professional software supports the function of automatic back blow unloading and automatic end of the test to ensure the smooth progress of the test process The instrument meets many national and international standards such as GB / T 15171 and ASTM d3078 It is suitable for the sealing test of packaging bags, bottles, tubes, cans and boxes of various materials in food, pharmaceutical, medical equipment, daily chemical, automobile, electronic components, stationery and other industries It can also be used for the sealing performance test of samples after drop and pressure test Fig 1 mfy-01 sealing tester 2 The preparation of the sample has three representative PE black and white film finished products packed with fresh milk, which are placed in the normal laboratory environment 3 Place of test conditions: Jinan Languang packaging safety testing center test temperature and humidity: normal laboratory environmental conditions test method: negative pressure method 4 Test step 4.1 test principle mfy-01 The sealing tester determines the sealing performance of the sample by vacuuming the vacuum chamber to produce the internal and external pressure difference of the sample immersed in water, and observing the gas escaping from the sample; or, without adding water, by vacuuming the vacuum chamber to produce the internal and external pressure difference of the sample, observing the sample expansion and the recovery of the sample shape after vacuum release, so as to determine the sealing performance of the sample 。 4.2 place the sample in the vacuum sealed tank (i.e vacuum chamber) and put a proper amount of distilled water, then immerse the sample in water At this time, the distance between the top of the sample and the water surface shall not be less than 25 mm Fig 2 close the vacuum pump switch and cover the sealing cover of the vacuum chamber in the test step 4.3 after placing the sample After setting the fixed pressure value, turn on the vacuum pump to vacuumize the vacuum chamber When the vacuum reaches a certain degree, stop vacuumizing and keep the vacuum for a certain time Observe the leakage of the sample during vacuumizing and vacuum holding, and observe whether there is continuous bubble Close the vacuum pump, make the vacuum chamber open to the atmosphere, open the sealing cover, take out the sample, wipe the water on its surface, open the seal if necessary, and check whether there is test water penetrating into the sample Turn off the power of the instrument 3 The expanded sample state after reaching the fixed pressure in this test, the sealing performance of fresh milk PE black-and-white film finished product packaging sample is better, there is no continuous bubble caused by leakage under the larger - 88.7 kPa, and there is no leakage in other parallel samples Therefore, the fresh milk package submitted for inspection will not leak under a large pressure, and its sealing performance is good, which can meet the basic quality requirements of the shelf life Conclusion: when mfy-01 sealing tester is used to test the sealing performance of liquid milk, the test results can be obtained and intuitionistic, which can accurately reflect the sealing effect of finished product packaging and whether there is the problem of package expansion and deterioration caused by leakage Therefore, when it is suspected that the sealing of the finished product package is prone to air leakage, the sealing tester based on the principle of negative pressure method should be used for the sealing test of the whole package Liquid milk PE black and white film packaging is only a typical representative of the whole packaging of various materials Other packaging materials such as milk powder aluminum plastic packaging bags, pastry plastic packaging bags (boxes), etc can use the sealing tester and follow this test method Labthink Languang has been committed to providing professional testing services and equipment for customers all over the world Over the years, it has solved quality problems such as product sealing and barrier for tens of thousands of customers around the world For more information about related testing instruments, you can log in to Languang for specific information or call directly for consultation Labthink is looking forward to enhancing technical exchanges and cooperation with users in various industries Copyright notice: All rights reserved Jinan Languang mechanical and Electrical Technology Co., Ltd no reprint without permission!
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