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What is Seal Strength Integrity Testing?

Seal strength testing measures the strength of seals in flexible materials. This test type can also be conducted on seals between a flexible material and rigid material. This ensures the proper bonding of materials to maintain package integrity.

As an ISTA and ISO 17025 certified lab, we realize the importance of seal strength package testing. Meeting the seal integrity regulatory compliance requirements can be difficult. We understand the challenges and guide companies through the process.

Ready to get started? Request a quote to receive testing services customized to your specific needs. Contact us to receive more information on our seal strength testing capabilities.

Why is Seal Strength Integrity Testing Important?

Seal strength compliance testing is relevant to the opening force of flexible materials and package integrity. Testing of seals can measure the manufacturer’s ability to produce consistent seals.

Seal strength testing is commonly used in the medical device packaging industry. A key factor of medical device packaging is the ability of the package to remain sterilized. Oftentimes, a breach of sterility can result in product returns, replacement costs, and loss of customer trust. In some cases, medical devices may require a packaging system that will maintain its integrity when exposed to extreme environmental conditions.

Seal Strength Compliance Testing Procedures

Keystone Compliance recommends testing to ASTM F88, Seal Strength Testing of Pouches, and Flexible Materials for all of your seal strength compliance test needs.

ASTM F88 covers the measurement of the strength of seals in flexible barrier materials. First, a sample is chosen to represent an adequate amount of packaging units. Next, the samples are conditioned to 23 °C and relative humidity of 50%. The units under testing may be subjected to 40 hours of conditioning.

After conditioning, the tensile machine is calibrated according to the manufacturer. There are a total of three procedures to choose from.

Technique A: Each tail of the specimen is secured in opposing grips and the seal remains unsupported during testing.

Technique B: Each tail of the specimen is secured in opposing grips and the seal remains hand-supported at a 90-degree perpendicular angle to the tails.

Technique C: The least flexible tail is supported flat against a rigid alignment plate held in one grip. The more flexible the tail is folded 180 degrees over the seal and is held in the opposing grip. 

A tensile testing machine to carry out seal strength testing is equipped with a device for recording the tensile load and amount of separation of the grips. Flexible materials are indicated as a material with flexural strength and thickness permitting a turn back at an appropriate 180 degrees.

The maximum seal force must also be considered. For some applications, the average force to open a seal may be useful. The average force required to separate a test strip of material containing a seal may indicate a failure.

Lastly, a test report is written with the following information. The list below is not intended to be all-inclusive.

  • Identification of the material being tested
  • Equipment and test method used
  • Ambient conditions during testing
  • Grip separation rate
  • Initial grip separation distance
  • Number of specimens tested
  • Any pertinent information that can affect test results

Keystone Compliance Seal Strength Equipment and Capabilities

Keystone utilizes pressure delivery systems, vacuum chambers, and open/closed package test fixtures to provide expert seal strength package integrity testing. Our dozens of thermal chambers range from reach-in to large walk-in chambers up to 1,300 cu. ft.

Keystone Compliance also owns numerous shakers and dynamic shock machines to provide the peace of mind that all your package integrity needs are met under one roof.

Expert Regulatory Compliance Package Test Laboratory

In addition to seal strength compliance testing, Keystone Compliance has a full scope of expertise including vibration, accelerated aging, and compression. We can accommodate flexible and rigid packages of all sizes, including large pallets. Our team strives to give our customers more time and energy on product development instead of testing.

Contact us to learn first hand why so many companies partner with Keystone to achieve their package certification needs. Ready to get started? We are. Request a quote to receive testing services customized to your specific needs.