Study on the influence of clamping method of aluminized film on the result of moisture resistance

Abstract: aluminized film plays an important role in the field of soft plastic packaging material, which is a kind of packaging material with high barrier In this paper, the moisture resistance data of aluminized film samples were tested with Labthink blue light W3 / 330 water vapor transmission test system under the conditions of aluminum plating side towards high humidity side and non aluminum plating side towards high humidity side, which provided reference for enterprises in designing package structure and testing moisture resistance of soft plastic packaging Key words: aluminized film, aluminized surface, non aluminized surface, moisture resistance, water vapor transmittance, water vapor transmittance test system 1 Meaning aluminized film is a soft plastic packaging material formed by coating a very thin layer of alumina on the surface of plastic film with special processes such as vacuum aluminizing Common aluminized films include pet (VMPET), CPP (VMCPP), BOPP (vmbopp), etc These aluminized films can be used as packaging materials alone, or can be compounded with other film materials to form aluminized composite films to serve as the outer packaging of products For aluminized films, due to the existence of the aluminized layer, the film's properties such as air resistance, moisture resistance, light shielding and fragrance retention have been greatly improved At the same time, the material has metallic luster, bright appearance, which can beautify the packaged products very well, and the packaging cost is relatively low In view of these advantages of aluminized films, more and more products have adopted it As packaging materials, such as coffee, milk powder, chips, mustard, granule or powder medicine, tea, candy and so on Fig 1 the barrier property of aluminized film is related to the density, thickness and process of aluminized layer The barrier property of some aluminized films will be reduced when they are in high humidity environment, which is probably because the high humidity environment will destroy the structure of the aluminized layer, cause irreversible damage to the aluminized layer, and then seriously affect the overall barrier performance of the film 2 Reference standards At present, there are weighing method (cup method), electrolysis method, humidity method and infrared method for measuring the water vapor transmission rate of soft plastic packaging in China The reference standards are gb1037-1988 test method of water vapor permeability of plastic film and sheet cup method, GB / t16928-1997 test method of water vapor permeability of packaging materials, GB / t21529-2008 plastic film and sheet Determination of water vapor transmission -- Electrolytic sensor method, GB / t30412-2013 determination of water vapor transmission of plastic film and sheet humidity sensor method, GB / t26253-2010 determination of water vapor transmission of plastic film and sheet infrared detector method The reference standard of this paper is GB / t21529-2008, i.e electrolytic sensor method 3 Test sample aluminum coating produced by a packaging material factory 4 Test equipment in this paper, the W3 / 330 water vapor transmittance test system independently developed and produced by Jinan Languang Electromechanical Technology Co., Ltd is used to test the water vapor transmittance corresponding to different test faces towards the high humidity side Fig 2w3 / 330 water vapor transmittance test system 4.1 equipment principle this equipment adopts the electrolytic sensor method test principle research and development During the test, nitrogen with stable relative humidity flows on one side of the film, and dry nitrogen flows on the other side of the film Due to the existence of humidity gradient, water vapor will diffuse from the high humidity side through the sample to the low humidity side On the low humidity side, the water vapor will be carried to the sensor by the flowing dry nitrogen, generating the electrical signal of the same proportion Through the analysis of the electrical signal of the sensor The water vapor transmittance of the sample is calculated If the test sample is a packaging container, the dry nitrogen flows in the container and the outside of the container is in a high humidity state 4.2 scope of application (1) this equipment is applicable to the test of water vapor transmittance of film, sheet, paper, paperboard, composite material, container and other packages Among them, film category includes all kinds of plastic film, plastic composite film, paper plastic composite film, coextrusion film, aluminum coating film, aluminum foil, aluminum foil composite film, glass fiber aluminum foil composite film, etc.; sheet category includes all kinds of engineering plastic, rubber, building materials and other sheet materials, such as PP sheet, PVC sheet, PVDC sheet, etc.; paper, cardboard and their composite materials category includes paper, cardboard, etc., such as cigarette wrapped aluminum coating Paper, paper aluminum plastic composite sheet, etc.; containers include bottles, bags, cans, boxes, barrels made of plastic, rubber, paper plastic composite, glass, metal and other materials, such as Coke bottles, peanut oil barrels, Tetra Pak packaging, vacuum packaging bags, metal packaging bags, metal three piece cans, plastic cosmetics hose packaging, toothpaste hose packaging, jelly cups, etc In addition, through special configuration, the equipment can also be used for testing the water vapor transmission rate of special packaging parts such as medical blisters, plastic bottles of drugs, instant noodles bowls, paper cups, paper bowls, automobile oil tanks, battery plastic shells, etc (2) the equipment complies with GB / t21529, iso15106-3, din53122-2, ybb00092003 and other national and international standards 4.3 equipment parameters: the test range of thin film samples is 0.001-40g / (M2 · 24h), and the resolution is 0.001g / (M2 · 24h); the test range of container samples is 0.0001-0.2g / (PKG · 24h), and the resolution is 0.00001g / (PKG · 24h) The temperature range of the test is 15 ℃ ~ 55 ℃, the temperature control accuracy is ± 0.1 ℃; the humidity range is 0% RH, 35% RH ~ 90% RH, 100% RH, and the humidity control accuracy is ± 1% RH The equipment is equipped with three test chambers, all of which can be designed independently, the test process is not interfered with each other, and the test results are displayed independently The system Zui can support parallel connection of 10 instruments and establish a system for simultaneous test of 30 samples Provide standard membrane for system calibration to ensure the accuracy and generality of test data It can be combined with the oxygen transmittance test system to form a hybrid test system, which is controlled by a computer It is a convenient test method to test the water vapor and oxygen transmittance at the same time Support lystemtm laboratory data sharing system, and manage test results and test reports in a unified way 5 Test process (1) use a sample cutter to cut 6 samples from the surface of the aluminum coated sample Fig 3 cut sample of aluminizing film (2) take any three samples, and the aluminizing layer shall face the high humidity side, and be respectively clamped on three test chambers of the equipment (3) set parameters such as sample thickness, test temperature and test humidity (4) adjust the nitrogen pressure to make the humidity in the test chamber reach the set value, and adjust the nitrogen flow knob to make the nitrogen flow in the upper and lower chambers reach the standard value (5) click the "start test" option to start the test The instrument automatically calculates and displays the test results (6) the non aluminized surface of the remaining three specimens shall face the high humidity side and be clamped in the equipment Repeat steps (3) - (5) to test the water vapor transmittance 6 The results showed that the water vapor transmittance of the three samples was 1.431g / (M2 · 24h), 1.395g / (M2 · 24h) and 1.517g / (M2 · 24h), respectively, when the aluminized side was facing to the high humidity side, the water vapor transmittance of the three samples was 0.667g / (M2 · 24h), 0.654g / (M2 · 24h) and 0.670g / (M2 · 24h), respectively 7 Conclusion There will be a gap between the water vapor transmittance measured on different surfaces of some aluminized film products towards the high humidity side This phenomenon is mainly related to the adverse effect of high humidity environment on the aluminum coating with poor compactness Therefore, it is necessary to strengthen the detection of the moisture resistance of the aluminized film according to the characteristics of the packaged products and the humidity of the circulation environment, and design the packaging materials Enough attention should be paid to the structure and selection of packaging materials W3 / 330 water vapor transmittance test system is a professional test equipment used to test the moisture resistance of samples The equipment is simple in operation, high in test accuracy and good in repeatability Labthink Languang not only provides you with the packaging testing equipment, but also improves your intimate packaging testing services The testing equipment and services involved cover the barrier, flexibility, impact resistance, puncture resistance, heat sealing performance, sealing performance, solvent residue, evaporation residue, etc of the packaging materials Learn about the relevant equipment information and service content, and you can log on to Jiji Nanlanguang company check or call directly for consultation The more you understand, the more you trust! 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