Permeability of films is classified based on their gas transmission rate at a specific thickness. High barrier films exhibit the lowest transmission rate, followed by barrier films and low barrier films. Due to their superior gas barrier properties, high barrier films are increasingly important in the packaging industry.
Since most packaging materials undergo reprocessing steps like coextrusion or lamination, it's essential to test the permeability of the final product to ensure package quality. Reprocessing can alter the physical and chemical properties of the raw materials, affecting their permeability. The chosen test method can significantly impact the results. For instance, in the differential pressure method using a vacuum, the degree of vacuum achieved in the test chamber is critical. Standards like ASTM D 1434 and ISO 2556 specify the required vacuum level.
Several instrument parameters are crucial for accurate testing of high barrier films. For example, vacuum gauge and temperature control. The instrument must have a vacuum gauge with a suitable range and high precision as specified by relevant standards. The gauge's resolution, which defines the smallest detectable pressure change, is particularly important. A wider range often comes with lower resolution, requiring longer testing times for high barrier films. Temperature fluctuations can significantly affect permeability test results. The test instrument should ideally have a temperature control function or excellent insulation to minimize the impact of ambient temperature variations.
Labthink C130H Gas Permeability Tester is based on the differential pressure method, and is professionally applicable to the determination of gas transmission rate, solubility coefficient, diffusion coefficient and permeability coefficient of plastic films, composite films, high barrier materials, sheets, and metal foils. Its Excellent temperature and pressure control technique and high precision vacuum sensor enables tests of ultra-high barrier property at different temperatures.
Testing high barrier films requires longer durations compared to other films due to their low gas permeability. The pressure change in the test chamber during the test is also minimal for high barrier films. This necessitates a longer testing time to collect enough data for accurate measurement.
Testing high barrier films demands meticulous attention to test conditions, equipment specifications, and test procedures. Careful selection of instruments with high-precision vacuum gauges and effective temperature control is essential. Since high barrier films exhibit minimal pressure changes during testing, extended test durations are necessary for reliable results.
As the demand for functional packaging materials grows, testing methods are evolving to ensure a more comprehensive evaluation of packaging films. Labthink encourages collaboration with packaging industry companies for quality control! Visit the website www.labthink.com to learn more!
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