5/26/2024

Simulating Real-World Stresses: Flex Durability and Water Vapor Transmission Rate (WVTR) Testing for Aluminum Plastic Composite (APC) Film


Aluminum plastic composite film (APCF) is a popular choice for pharmaceutical packaging due to its excellent barrier properties against moisture and oxygen. This helps extend the shelf life and maintain the quality of sensitive medications. However, the film's effectiveness can be compromised during various stages like forming, filling, sealing, and transportation. This article discusses the importance of testing the moisture barrier property of APC film after simulating these stresses.


 

APCF typically consists of layers of plastic film bonded to a central aluminum layer. The aluminum acts as the primary barrier against moisture vapor transmission (MVTR). However, flexing the film during processing can create pinholes or weaknesses in the aluminum layer, allowing moisture to penetrate and potentially degrade the pharmaceuticals.

To ensure the integrity of the moisture barrier, manufacturers and users perform water vapor permeability (WVP) tests on APC film samples. These tests are conducted after subjecting the film to a flex durability test, mimicking the stresses encountered during real-world scenarios.

Flex Durability Test (ASTM F392): This standard outlines the procedure for simulating flexing experienced by packaging materials. Specimens of the APC film are mounted in a Labthink C681M Flex Durability Tester. The tester applies a combination of twisting and horizontal motions for a specified duration (e.g., 6 minutes or 270 cycles) at standard atmospheric conditions (23°C and 50% relative humidity).


 

After the flex durability test, the WVP of the stressed film samples is measured using a Labthink C360M Water Vapor Transmission Rate Tester for a water vapor transmission rate test. This instrument employs a gravimetric method (cup method) where a specific amount of water is placed in a dish. The APC film sample is then mounted on the dish, creating a sealed chamber. The entire assembly is placed in a controlled environment, and the amount of water vapor permeating through the film over time is measured. The instrument automatically conducts the test and provides the final WVP result.



 

By measuring the WVP after the flex durability test, manufacturers and users can evaluate the effectiveness of the APC film in maintaining its moisture barrier properties under real-world stresses; ensure the film meets the WVP requirements for specific pharmaceutical packaging applications; and identify any potential weaknesses in the film's structure or manufacturing process that could compromise its moisture barrier performance.

Regular testing with these instruments helps ensure the ongoing quality and effectiveness of APC film in protecting pharmaceuticals from moisture-related degradation throughout the product lifecycle.



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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