Oxygen Transmission Rate (OTR) ASTM D3985
Oxygen Permeation of Flexible Barrier Materials Using a Coulometric Sensor ASTM D3985, ISO 15105
The use of flexible barrier materials is essential for packaging and industrial applications where the protection of contents from exposure to oxygen is critical. To ensure the effectiveness of these materials, it is important to determine their oxygen transmission rate (OTR). The OTR is a measure of how much oxygen can pass through a material over a specific period of time. The results of this test are used to evaluate the barrier properties of the material and to ensure the integrity of the packaged product.
Several factors can impact the material permeation, including the thickness of the material, temperature, and relative humidity. Therefore, it is crucial to understand these factors when determining the OTR of the barrier material.
To determine the OTR, a standard test method has been established by the American Society for Testing and Materials (ASTM D3985). This method involves sealing a sample of the barrier film between two chambers, one containing oxygen and the other void of oxygen. The sealed chambers are maintained at a selected temperature and relative humidity for a specified duration, typically between 24 to 72 hours. During this time, the oxygen that passes through the material is measured by a coulometric sensor.
The test area for determining the OTR is typically 50 square centimeters, and the results are reported in mol per square meter per second (mol/(m2•s)). This unit of measurement reflects the amount of oxygen that passes through a square meter of material in one second.
The results of the OTR test are used to compare the barrier properties of different materials, and to identify the most suitable material for a particular application. For example, a high OTR indicates that the material is permeable to oxygen, which may not be suitable for products that require an extended shelf life. Conversely, a low OTR suggests that the material provides effective oxygen barrier properties, making it an ideal choice for products that need to be protected from oxygen exposure.
Determining the OTR of flexible barrier materials is essential for ensuring the quality and safety of products. ASTM D3985 provides a standardized method to measure the OTR of these materials, and the results can be used to compare and select materials based on their barrier properties. By understanding the OTR and the factors that influence it, manufacturers can select the most appropriate material for their product packaging and industrial applications.