Abstract: The test temperature is an important factor that affects the test results of the water vapor transmission rate of the packaging material. This paper analyzes the effect of the test temperature on the moisture resistance of the packaging material by testing the water vapor transmission rate of the material at different temperatures and introduces the test Principles, equipment C390 water vapor transmission rate test system parameters and application scope, test process, etc., provide a reference for enterprises to monitor the water vapor transmission rate of materials at different temperatures.
Keywords: water vapor transmission rate, moisture resistance, temperature, water vapor transmission rate test system, packaging materials, infrared sensor method
1. Significance
Water vapor transmission rate is an index to evaluate the moisture resistance of packaging materials, an important factor that affects the protective function of packaging materials on the packaged products, and an important barrier to prevent products from moisture, mold, and agglomeration. There are many factors that affect the water vapor transmission rate of packaging materials, such as packaging material, thickness, internal structure of the material, temperature, humidity and other environmental conditions. Generally speaking, materials containing aluminum foil, PVDC, aluminum coating, oxide coating, etc. The water vapor transmission rate of the package is low. The thicker package of the same material, the higher the degree of crystallinity and orientation, the higher the moisture resistance. In addition, the different use or storage environment of the packaging material will also affect its water vapor permeability. Excessive rate, so for the already formed packaging materials, the storage and circulation environment can be controlled to make the moisture resistance of the packaging materials meet the product quality requirements. This paper tests the water vapor transmission rate of the material at different test temperatures, and analyzes the change of the material's moisture resistance with temperature.
2. Test basis
The test methods for the water vapor transmission rate of packaging materials are cup method, electrolytic sensor method, humidity sensor method, infrared sensor method, etc. This test is based on the infrared sensor method to test samples, and the standard is GB / T 26253-2010. Determination of water vapor transmission rate of plastic films and sheets. Infrared detector method.
3. Test samples
In this paper, the plastic film produced by an enterprise is used as a test sample to test its water vapor transmission rate under the conditions of 25 ℃, 90% RH and 38 ℃, 90% RH.
4. Test equipment
The test equipment used in this test is the C390 water vapor transmission rate test system, which was independently developed and produced by Jinan Languang Electromechanical Technology Co., Ltd.
Figure 1 C390 water vapor transmission rate test system
4.1 Test principle
The infrared sensor method is based on the principle of quantitative absorption of infrared light by water molecules. The water vapor transmission rate of the sample is calculated by testing the attenuation of infrared light before and after passing through the carrier gas containing water molecules. During the test, the test chamber of the equipment is divided into two upper and lower test chambers by the sample. The upper chamber is the high humidity side and the lower chamber is the low humidity side. Water vapor will penetrate through the sample from the upper chamber to the lower chamber and be lowered. The carrier gas nitrogen in the cavity is carried to the infrared sensor for testing, thereby obtaining the water vapor transmission rate of the sample.
4.2 Device parameters
When the test area of ​​film samples is 50 cm2, the test range is 0.05 ~ 40 g / (m2 · 24h), when the test area is 7 cm2, the test range is 0.35 ~ 280 g / (m2 · 24h); The range is 0.00025 ~ 0.2 g / (pkg · d); the test temperature control range is 15 ℃ ~ 55 ℃, the temperature control accuracy is ± 0.2 ℃; the humidity range is 5% RH ~ 90% RH, 100% RH, the humidity control accuracy It is ± 2% RH; the three test modes of manual, proportional, and cyclic provide suitable detection methods for materials with different barrier properties; using the second-generation three-chamber integrated block, the three test chambers can be designed independently, and the test process is mutual No interference, the test results are displayed independently.
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, 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 and other sheet materials, such as PP sheet, PVC sheet, PVDC sheet, etc .; paper, cardboard and composite materials include paper, cardboard, etc., such as cigarette pack aluminum 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, such as tea aluminum cans, cola 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.
The device can also be extended to test the water vapor transmission rate of special packages such as solar backplanes, liquid crystal display films, medical blister, pharmaceutical plastic bottles, sterile protective wound films, automobile fuel tanks, battery plastic shells and other special packages.
(2) This equipment complies with GB / T 31355, ISO 15106-2, ASTM F1249, GB / T 26253, TAPPI T557, JIS K7129, YBB00092003.
5. Test process
5.1 Cutting
A special sample is taken to cut 6 specimens from the surface of the film sample to be tested and placed in an environment of 23 ± 2 ° C and 50 ± 10% for 4 h.
5.2 Water vapor transmission rate test at 25 ℃
(1) Apply a layer of vacuum grease around the three test chambers of the equipment, and take three samples to clamp them into the equipment.
(2) Set the test conditions (25 ℃, 90% RH), sample name, test mode and other parameter information, click the test option, the test starts. Turn on the gas source and adjust the carrier gas flow so that the humidity in the test chamber reaches the set value. After the test, the device displays the water vapor transmission rate of the sample.
5.3 Water vapor transmission rate test at 38 ℃
Except that the test temperature is set to 38 ° C, the rest of the process is tested according to the steps in 5.2.
6. Test results
Under the conditions of 25 ℃ and 90% RH, the water vapor transmission rates of the tested film samples were 3.11 g / (m2 · 24h), 3.09 g / (m2 · 24h), 3.17 g / (m2 · 24h), average The value is 3.12 g / (m2 · 24h); under 38 ℃, 90% RH, the water vapor transmission rate of the tested film samples are 6.91 g / (m2 · 24h) and 6.86 g / (m2 · 24h) , 6.83 g / (m2 · 24h), the average value is 6.87 g / (m2 · 24h).
7. Conclusion
It can be seen from the test process that the operation of the equipment is simple and the degree of intelligence is high; from the test results under each test condition, the deviation between the test values ​​is small, the repeatability is good, and the accuracy of the test results is high; The average value of the test results under various test conditions shows that the water vapor transmission rate at 38 ℃ is significantly higher than the water vapor transmission rate at 25 ℃, that is, the humidity resistance of the film sample tested in the environment of 25 ℃ is more high. Jinan Languang Electromechanical Technology Co., Ltd. is a high-tech enterprise specializing in R & D, production and packaging testing services of packaging testing equipment. The testable items cover the full range of packaging materials performance, such as oxygen permeability, nitrogen permeability, carbon dioxide permeability , Water vapor transmission rate, tensile properties, heat seal strength, sealing performance, tear strength, friction coefficient, solvent residue, total migration, etc. The more you understand, the more you trust! Labthink looks forward to enhancing technical communication and cooperation with enterprises and institutions in the industry!
Adult Hair Clippers,Electric Hair Trimmer,Rechargeable Hair Clipper,Waterproof Hair Cutter
Ningbo Beilun Xuanfeng Molding Co., Ltd. , https://www.schelfern.com