Seal strength testing

Seal strength testing of packaging refers to the process of evaluating the mechanical strength or bond of seals in various types of packaging materials. It involves measuring the force required to break or separate the sealed surfaces of the packaging. The purpose of seal strength testing is to assess the integrity and reliability of the seals in packaging. A strong and reliable seal ensures that the package remains intact, preventing leaks, contamination, or spoilage of the contents. By conducting seal strength testing, manufacturers can determine if the seals meet the required strength specifications and ensure that their packaging provides adequate protection for the products throughout their lifecycle. In this article, we extensively discuss the commonly used seal strength testing method and compare it to the seal integrity testing method and the vacuum decay test method, which is the method we employ for testing packaging materials. 

The ASTM F88 standard is widely recognized and considered the most common seal strength test method. It provides a comprehensive framework for evaluating the mechanical strength of seals in packaging materials. The destructive ASTM F88 test method outlines a series of steps and requirements to ensure accurate and consistent results. These include preparing the samples according to specified dimensions, selecting appropriate test equipment, and applying controlled forces to the sealed area. The test involves securing the sealed portion of the packaging material between two clamps or jaws and applying a controlled force in a consistent manner until the seal breaks. The force required to break the seal is then measured and recorded. 

The scope of the seal strength testing ASTM F88 encompasses a range of applications, including food packaging, pharmaceutical packaging, and industrial packaging. It is applicable to a wide variety of flexible barrier materials commonly used in these industries. It is the standard test method for seal strength of flexible barrier materials, such as plastic films, aluminum foil, and laminated materials.

The heat seal strength test method is a specific variant of seal strength testing, used to evaluate the strength of heat-sealed packaging materials. This test involves using heated jaws to create a seal between the samples. Factors such as temperature, pressure, and the condition of the seal surfaces can influence the heat seal strength. By performing this test, manufacturers can assess the quality and reliability of their heat-sealed packaging, ensuring it can withstand intended conditions and provide reliable protection for the packaged products. 

In a previous article on seal integrity testing, we discussed ASTM F1886, a visual inspection method for assessing the integrity of a package’s seal. At Oxipack, we utilize the vacuum decay method (ASTM F2338), a non-destructive leak detection method that allows for testing the overall integrity of the entire packaging for leaks and defects. However, what are the specific differences between ASTM F88, ASTM F1886, and ASTM F2338?

The seal strength testing method is primarily focused on measuring the mechanical strength or bond of a seal between two surfaces. It involves applying a controlled force to the sealed area until the seal breaks, and measuring the force required to separate the surfaces. Seal strength testing is a destructive testing method, as it breaks the seal during testing. 

Seal integrity testing is specifically designed to evaluate the integrity of a seal and determine if any leaks or breaches are present. It typically involves subjecting the sealed package to a specific internal or external pressure differential and observing if any leaks occur. It is a non-destructive method, but it doesn’t provide information about the strength of the whole integrity of the packaging.  

Vacuum decay testing is focused on detecting leaks, breaches and checking the integrity of sealed packages. It is a non-destructive method and creates a vacuum around the package and monitors the pressure changes over a specified period to determine if there are any micro leaks or big leaks present.  

The combination of vacuum decay, seal integrity testing, and seal strength testing offers a comprehensive approach to packaging quality assurance. These methods work together to assess different aspects of the packaging, including leak detection, seal integrity, and seal strength, ensuring that the packaging provides optimal protection and meets the desired quality and safety standards. 

Please feel free to contact us for more information about our method and how to implement it. We are happy to provide further assistance and answer any questions you may have. 

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