Abstract: The shelf life of military food is generally long, and its packaging materials should have excellent performance to ensure that the food is of good quality during storage. This paper uses the W3 / 330 water vapor transmission rate test system to test the water vapor transmission rate of a military food packaging material, and introduces the test principle, test process and equipment parameters, scope of application, etc., for monitoring military packaging materials Provide a reference for the selection of effective means of moisture resistance.
1. Meaning
When marching, fighting, or performing special tasks, food is an indispensable supply to keep the team alive and improve combat effectiveness. Out of consideration for military strategy and material reserves, the shelf life of military food is generally more than 2 years, which requires that its packaging materials should have excellent performance to ensure the quality of the food during storage. In addition, the uncertainty of the way of supplying materials and environmental conditions has put forward higher requirements for packaging materials. Among them, moisture resistance is one of the important performances of military food packaging, and it is a key factor that affects the amount of water vapor penetration into the interior of the packaging. Moisture is a necessary condition for the growth and reproduction of microorganisms. Therefore, when more moisture is exposed, the food is not only susceptible to moisture absorption, caking, soft skin, etc., but also increases the risk of mildew, and it has a high barrier to water vapor. (That is, excellent moisture resistance) packaging materials can significantly reduce the penetration of water vapor into the package, which plays an important role in preventing food deterioration.
Reducing volume and reducing weight are the basic characteristics of military food. With the advancement of packaging technology and the research and development of polymer materials, military food packaging has gradually transitioned from tinplate cans to flexible plastic composite bags and tubes. The vapor transmission rate is not the same. In order to ensure the quality of military food during storage, it is necessary to strengthen the detection and monitoring of the moisture resistance of such materials.
Figure 1 Common military food packaging forms
2. Test samples
This paper uses a certain aluminum-plastic composite film for military food packaging as a test sample to test its water vapor transmission rate.
3. Test basis
This test uses the electrolytic method to test the moisture resistance of the samples. The test is based on GB / T 21529-2008 "Determination of Water Vapor Transmission Rate of Plastic Films and Sheets-Electrolytic Sensor Method".
4. Test equipment
This article uses the W3 / 330 water vapor transmission rate test system as the test equipment to detect the water vapor transmission rate of the sample. This equipment is independently developed and produced by Jinan Languang Electromechanical Technology Co., Ltd.
Figure 2 W3 / 330 water vapor transmission rate test system
4.1 Test principle
The electrolytic sensor method is based on the quantitative relationship between electrolytic water molecules and electrolytic current to test the amount of water vapor that has penetrated through the sample. During the test, the test chamber of the equipment is divided into upper and lower chambers with a sample. The upper chamber is filled with a certain humidity of nitrogen, the lower chamber is dry nitrogen, and the water vapor is affected by the difference in humidity. The cavity penetrates into the lower cavity through the sample, and the nitrogen in the lower cavity carries the permeated water vapor to the electrolytic sensor for electrolytic analysis, and finally the water vapor permeability of the sample is obtained.
4.2 Device parameters
0.001 ~ 40 g / (m2 · 24h) with a resolution of 0.001 g / (m2 · 24h); the test range of container samples is 0.0001 ~ 0.2 g / (pkg · 24h) with a resolution of 0.00001 g / (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 does not interfere with each other, and the test results are displayed independently. The system can support up to 10 instruments connected in parallel to establish an efficient system for 30 samples to be tested simultaneously. Provide standard membrane for system calibration to ensure the accuracy and versatility of test data. It can be combined with the oxygen transmission rate test system to form a hybrid test system, which is controlled by a computer and realizes an efficient and convenient test method for simultaneous testing of water vapor and oxygen transmission rates. Support LystemTM laboratory data sharing system, unified management of test results and test reports.
4.3 Scope of application
(1) This equipment is suitable for testing the water vapor transmission rate of packaging materials such as films, sheets, paper, cardboard and their composite materials, and containers. Films include various plastic films, paper-plastic composite films, co-extruded films, aluminized films, aluminum foil, aluminum foil composite films, glass fiber aluminum foil paper composite films, etc .; sheet materials include various engineering plastics, rubber, building materials, etc. Shaped materials, such as PP sheet, PVC sheet, PVDC sheet, etc .; paper, cardboard and composite materials including paper, cardboard, etc., such as cigarette pack aluminized paper, paper aluminum plastic composite sheet, etc .; containers include plastic , Rubber, paper, paper-plastic composite, glass, metal and other materials made of bottles, bags, cans, boxes, barrels of water vapor transmission test, such as Coke bottles, peanut oil barrels, Tetra Pak packaging, vacuum packaging bags, metal Packaging bags, metal three-piece cans, plastic cosmetic tube packaging, toothpaste tube packaging, jelly cups, etc.
In addition, through special configuration, the device can also be used to test the water vapor transmission rate of special packages such as medical blister, medicine plastic bottle, instant noodle bowl, paper cup, paper bowl, automobile fuel tank, battery plastic shell and so on.
(2) This equipment complies with GB / T 21529, ISO 15106-3, DIN 53122-2, YBB00092003 and other national and international standards.
5. Test process
5.1 Cutting
Use a special sampler to cut 3 samples from the sample to be tested.
5.2 Loading
Apply vacuum grease to the surface of the three test chambers of the equipment, install three samples on the three test chambers, and clamp them with clamping devices to ensure a good seal between the sample and the test chamber.
5.3 Test
Set the sample name, sample thickness, test mode, test temperature, humidity and other parameter information, turn on the gas source, adjust the nitrogen pressure, so that the humidity in the test chamber reaches the set value, turn the carrier gas flow adjustment knob to make the upper and lower chambers The flow of nitrogen in the standard meets the standard requirements. Click the test option to start the test. The equipment is tested according to the set parameters, and the test results are displayed after the test.
6. Test results
The water vapor transmission rates of the three samples tested in this test were 0.079 g / (m2 · 24h), 0.083 g / (m2 · 24h), 0.088 g / (m2 · 24h), the aluminum-plastic composite membrane sample The water vapor transmission rate is the average of the test results of the three samples, which is 0.083 g / (m2 · 24h).
7. Conclusion
Water vapor transmission rate is an important parameter index to measure the moisture resistance of military food packaging, which directly affects the quality of food during the shelf life. This paper uses the electrolysis sensor method equipment-Labthink W3 / 330 water vapor transmission rate test system to test the water vapor transmission rate of military food packaging aluminum-plastic composite film samples. The entire operation process is simple, the degree of intelligence is high, and the test results Accurate and reliable, it can truly reflect the moisture resistance of the tested samples. Jinan Languang Electromechanical Technology Co., Ltd. is a high-tech enterprise specializing in R & D and production of packaging and testing equipment and packaging and testing services. The existing equipment has been used in automobiles, medical, food, packaging, health care products, daily chemical supplies, universities and research institutes Institutes, third-party testing and inspection institutions and other industries and fields, to understand the relevant equipment and testing service information. The more you understand, the more you trust! Labthink looks forward to enhancing technical communication and cooperation with enterprises and institutions in the industry.
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