Abstract: The carbon dioxide barrier performance of packaging materials is an important factor affecting the quality assurance effect of modified atmosphere packaging filled with carbon dioxide.
Verify the preservation of the sample against carbon dioxide gas inside the package
By introducing the test principle, test process, equipment parameters and scope of application, it can provide a reference for enterprises to monitor the carbon dioxide barrier performance of flexible plastic packaging
Key words: carbon dioxide transmission rate, modified atmosphere packaging, quality-preserving effect, differential pressure gas permeameter, flexible plastic packaging materials, barrier properties Therefore, the packaging of many products adopts modified atmosphere packaging containing carbon dioxide to make full use of the above-mentioned properties of carbon dioxide to prevent products from mildew, rancidity, and prolong shelf life.
For example, a certain proportion of oxygen and nitrogen are filled in the packaging of fresh meat products.
, carbon dioxide mixed gas to keep meat products bright red, prevent meat products from oxidizing, and inhibit the reproduction of aerobic microorganisms; fresh fruits can be adjusted and inhibited by using a suitable proportion of oxygen and carbon dioxide mixed gas as the modified atmosphere packaging gas to control and inhibit the respiration of fruit.
For modified atmosphere packaging, the proportion of gas components in the package directly affects the quality of the package.
Selecting packaging materials with suitable gas barrier properties to prevent excessive loss or accumulation of gas inside the package is an important measure to ensure the stability of the proportion of each component of the mixed gas
This paper introduces the test method of carbon dioxide transmission rate through the test of carbon dioxide barrier property of flexible plastic packaging materials
Test basis At present, the test method for the carbon dioxide permeability of flexible plastic packaging materials is mainly the differential pressure method.
This standard is suitable for testing the gas permeability and gas permeability coefficient of various test gases such as oxygen, air, nitrogen, and carbon dioxide
Test samples The test samples tested in this paper are plastic composite film packaging materials
Test equipment The test equipment used in this sample is a VAC-V2 differential pressure gas permeameter, which is independently developed and produced by Jinan Languang Electromechanical Technology Co.
1 Test principle Differential pressure method refers to a test method in which a certain pressure difference is maintained on both sides of the sample during the test, and the gas permeation of the sample is calculated according to the change of the pressure on the low pressure side
The realization process is that after the sample is clamped into the test chamber of the equipment, the test chamber is divided into two test chambers, the upper and the lower chamber by the sample, the two test chambers are evacuated, and then the upper chamber is filled with a certain pressure of test gas, In this way, a certain pressure difference is formed on both sides of the sample, and the test gas penetrates from the upper chamber through the sample to the lower chamber under the action of the pressure difference.
parameters such as permeability and permeability coefficient
2 The test range of equipment parameters is 0.
05 ~ 50000 cm3/(m2 24h 0.
1MPa), and the vacuum resolution can reach 0.
1 Pa; the temperature control range is 5℃ ~ 95℃, and the temperature control accuracy is ±0.
1℃; the humidity control range is 0%RH, 2%RH ~ 98.
5%RH, 100%RH, the humidity control accuracy is ±1%RH, which can meet the testing needs of customers under different test conditions; there are three completely independent test chambers, which can test three identical or different samples; data fitting at any temperature can be performed, and test results under very special test conditions can be easily obtained; after modification, this equipment can also support the test of toxic gases, flammable and explosive gases; standard membranes are provided for testing Quick calibration to ensure the accuracy and versatility of test data; support LystemTM laboratory data sharing system, unified management of test results and test reports
3 Scope of application (1) This equipment is specially used for the transmission rate, permeability coefficient and solubility of various gases (such as oxygen, carbon dioxide, nitrogen, helium, air, etc.
) of various films and sheet samples at various temperatures Coefficient, diffusion coefficient test
Films include various plastic films, paper-plastic composite films, co-extruded films, aluminized films, aluminum foils, aluminum foil composite films and other film materials; sheets include various engineering plastics, rubber, building materials and other sheet materials, such as PP Sheet, PVC sheet, PVDC sheet
(2) The equipment can also be extended to the air permeability test of aerospace materials, paper and cardboard, paint film, glass fiber cloth, glass fiber paper, cosmetic hose sheets, various rubber sheets and other materials
(3) This equipment can meet many national and international standards, such as GB/T 1038, ISO 15105-1, ISO 2556, ASTM D1434, JIS K7126-1, YBB00082003,
Test process (1) Use a special sampler to cut 3 samples with a diameter of 97 mm from the surface of the sample
(2) Place the sample in a desiccator at 23±2℃ for 48 hours
(3) After the sample is taken out, its thickness is measured, and the average value of the measurement is taken as the thickness of the sample
(4) Apply a layer of vacuum grease around the test chamber, place a piece of filter paper in the test area, then clamp the sample to the test chamber and clamp it with the clamping structure
(5) Connect the carbon dioxide gas source, set the sample name, thickness, test humidity, test temperature, test mode and other parameter information, turn on the vacuum pump, and click the test option to start the test
After entering the test state, turn off the vacuum pump
After the test, the device automatically displays the test values of the three samples
Test results The carbon dioxide transmission rates of the three samples tested in this test under the conditions of 23℃ and 0%RH were 80.
1MPa) and 81.
1MPa), and the average value is 79.
Conclusion For the modified atmosphere packaging containing carbon dioxide gas, the carbon dioxide permeation rate of the packaging material is the performance index that should be paid attention to.
The level of this index value directly affects the change of the proportion of each gas component in the package with the storage time
This paper introduces the method of testing the carbon dioxide barrier performance of flexible plastic packaging by the differential pressure method through the test of the carbon dioxide permeation of plastic composite film samples.