Aluminum-coated films offer a cost-effective alternative to pure aluminum foil for packaging applications requiring good barrier properties. However, the effectiveness of these films can vary depending on the substrate material used. This study investigates the Oxygen Transmission Rate (OTR) of VMPET (vapor-deposited aluminum on PET) and VMBOPP (vapor-deposited aluminum on BOPP) to assess the influence of the substrate on barrier performance.
The OTR test employed the coulometric method (equal pressure) following the standard ASTM D3985. This method utilizes a controlled environment chamber to measure the rate of oxygen permeation through the film sample.
Labthink C230H Oxygen Transmission Rate Test System was used for this study. This instrument is designed and manufactured based on the coulometric sensor method (aka. equal pressure method) and conforms to ASTM D3985. This instrument can be used to measure the oxygen transmission rate of barrier materials with high and medium barrier properties with high accuracy and high efficiency.
Three specimens were cut from each VMBOPP and VMPET sample material using a sample cutter. These specimens were then clamped into the designated test cells of the C230G instrument. The test parameters, including specimen name, temperature, and humidity, were programmed, and the test was initiated. Upon completion, the instrument automatically generated the OTR results for each specimen.
The OTR test results for the VMBOPP specimens exhibited a variation, with individual values of 50.0341 cm3/(m²∙day), 51.4492 cm3/(m²∙day), and 58.8713 cm3/(m²∙day). The average OTR for VMBOPP was calculated to be 53.4515 cm3/(m²∙day). Conversely, the VMPET specimens displayed significantly lower and more consistent OTR values. The individual results for VMPET were 1.0287 cm3/(m²∙day), 0.9347 cm3/(m²∙day), and 1.0973 cm3/(m²∙day), with an average OTR of 1.0202 cm3/(m²∙day).
The OTR test results clearly demonstrate that VMPET possesses superior barrier properties compared to VMBOPP. This can be attributed to the inherent better barrier properties of PET film compared to BOPP film. The C230G instrument proved to be a reliable and user-friendly tool for evaluating the OTR of packaging films. Its automated features, precise control of test conditions, and accurate data acquisition make it suitable for various quality control applications.
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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