Molecular flow model of gas transmission rate test device with auxiliary chamber for high barrier film

The oxygen barrier test of plastic film is an important step in the sealing and preservation process of food and drugs, and the system leakage is pivotal factor of the test device that affecting the efficiency and accuracy. In order to reduce the impact of system leakage on the oxygen barrier detection of plastic film, a test device with an auxiliary seal on the outer layer is designed by using series dual sealing structure technology. Based on the molecular flow states hypothesis, according to the conservation of gas throughput and the invariance of flow resistance, a mathematical model and simulation platform for permeability test of flexible packaging materials with high barrier with outer auxiliary sealing chamber and forward leakage are established. By using Laplace transform method, the analytical solutions and corresponding characteristics of the pressure and leakage rate changes in the inner and outer sealing chamber are discussed, and the equivalent test time expression of the forward leakage test device is derived. The simulation and measured results show that the equivalent test time of the test device with the outer auxiliary sealing chamber is much longer than 24 h, and the test results of the pressure change of the inner sealing chamber are the same as the ideal leak-free system. Compared with the single sealing structure test device, the test error of the same high barrier film permeability test is negligible. By using the test device with an auxiliary sealing chamber, the oxygen barrier property can be accurately measured without any leak measurement and correction.