Standard Test Method for Mechanical Seal Strength Testing for Round Cups and Bowl Containers with Flexible Peelable Lids - PDF

 

ASTM F2824 defines a standardized method to measure the seal strength between a flexible lid and a rigid or semi-rigid container, such as round cups, trays, and bowls.
This type of testing is important for evaluating packaging integrity in food, medical, and consumer products industries, where both easy opening and reliable sealing are critical.

This overview covers the purpose of ASTM F2824, the necessary equipment, the general testing procedure, and related standards.

Purpose of ASTM F2824

The main objectives of ASTM F2824 are to:

• Quantify the seal strength between the lid and the container.

• Evaluate the peel characteristics — such as force and uniformity — during the lid removal process.

• Support quality control, package design, and regulatory compliance for manufacturers.

• Identify weaknesses or defects in the heat-sealing process.

Understanding the mechanical seal strength ensures that products are securely packaged for protection while still being user-friendly for opening.

Equipment Required for ASTM F2824 Testing

To perform testing under ASTM F2824, you will need:

• Universal Testing Machine (UTM):

  • Capable of tensile testing with precise control over crosshead speed.

  • Fitted with a load cell appropriate for low to moderate force measurements (e.g., 10–500 N range).

• Specialized Peel Test Fixtures:

  • Grips or fixtures designed to securely hold the container body.

  • Peel grips or clamps to grip the flexible lid without tearing it.

  • Fixtures often need to support pulling the lid at an angle (typically 45 degrees or 90 degrees).

• Alignment Tools:

  • For ensuring consistent positioning of the sample for repeatable results.

• Environmental Chamber (optional):

  • If testing must simulate real-world conditions like refrigerated or heated storage.

• Measurement Tools:

  • Calipers for measuring container and seal dimensions.

Specimens

• Round cups, bowls, or trays sealed with a flexible, peelable lid (such as films, foils, or laminated materials).

• The seal must be formed using normal production processes to reflect actual product packaging.

General Test Procedure for ASTM F2824

1. Preparation:

   • Prepare test samples with lids attached via standard sealing methods (typically heat sealing).

   • Condition specimens if environmental testing is required (e.g., room temperature, refrigerated).

2. Mounting:

   • Secure the rigid or semi-rigid container in a fixture so that it will not move during the peel.

   • Attach the flexible lid to the tensile tester grips.

3. Testing:

   • Peel the lid away from the container at a controlled rate (usually 250 mm/min unless otherwise specified).

   • Perform the peel at the specified angle (commonly 90° or 45°).

   • Measure and record the force required to continuously peel the lid from the container.

4. Data Collection:

   • Record the maximum seal strength, average peel force, and force vs. displacement curve.

   • Note any irregularities like tearing, delamination, or sudden breaks in the seal.

Results and Reporting

A typical ASTM F2824 test report includes:

• Description of the package type and sealing method.

• Peel angle and peel speed.

• Maximum seal strength (peak force).

• Average seal strength (mean force).

• Observations on seal failure modes (cohesive failure, adhesive failure, tearing, etc.).

• Environmental conditions if relevant.

Related ASTM and Similar Standards

Other ASTM standards that address packaging seal strength and related peel tests include:

• ASTM F88 / F88M – Standard Test Method for Seal Strength of Flexible Barrier Materials:
  The most widely used general peel test for flexible packages (including pouches and bags).

• ASTM F1140 / F1140M – Standard Test Methods for Internal Pressurization Failure Resistance of Unrestrained Packages:
  Measures the burst and creep resistance of sealed packages under internal pressure.

• ASTM F2054 – Standard Test Method for Burst Testing of Flexible Package Seals Using Internal Air Pressurization:
  Specifically focuses on detecting seal weakness by pressurizing the package internally.

• ASTM F88 Annexes – Provide additional testing setups (e.g., supported vs. unsupported peel testing) that can relate depending on fixture type used.

Applications of ASTM F2824 Testing

ASTM F2824 is critical for ensuring:

• Medical device trays are securely sealed to maintain sterility.

• Food containers maintain freshness without leakage.

• Consumer packaging offers both durability during shipping and ease of use for customers.

Industries relying on this test include food and beverage, medical device manufacturing, pharmaceuticals, and consumer goods.

Conclusion

ASTM F2824 provides a clear, standardized approach for measuring the mechanical seal strength of flexible lids on rigid containers.
It helps manufacturers ensure their packaging meets the demands of durability, product safety, and customer convenience.
Often used alongside tests like ASTM F88, it is essential for complete package validation programs.