Understanding Seal Performance During Packaging

Emballasje til medisinsk utstyr plays a critical role in maintaining product sterility, safety, and reliability throughout storage, transportation, and clinical use. Unlike ordinary packaging, medical packaging must withstand strict quality requirements because seal failure may directly affect product protection.

During high-speed form-fill-seal operations, packaging materials are often exposed to mechanical stress immediately after sealing, when the seal is still hot and has not reached its final strength. This early-stage sealing performance is evaluated through the Hot Tack-test, which measures the ability of a hot seal to resist separation forces before complete cooling.

Den Hot Tack-test provides important information about sealing behavior and helps packaging engineers select suitable films, optimize sealing parameters, and reduce the risk of package failure during production.

Hot Tack Test and ASTM F1921 Evaluation of Hot Tack Strength

Den ASTM F1921 standard provides a widely recognized method for measuring the hot tack performance of heat-sealed flexible packaging materials. It evaluates the strength of a seal immediately after the sealing process while the polymer layers are still in a heated condition.

Formålet med Hot Tack-test is different from traditional heat seal strength testing. Heat seal testing generally evaluates the strength of a fully cooled seal, while hot tack testing focuses on the critical period immediately after sealing.

According to ASTM F1921, two film strips are sealed together under controlled conditions, including:

• Tetningstemperatur
• Tetningstrykk
• Contact time
• Cooling or delay time
• Testing speed

After the sealing jaws open, the sealed sample is pulled apart at a controlled speed. The maximum force required to separate the seal is recorded as Hot tack-styrke.

This measurement helps determine whether a packaging material can maintain seal integrity during automated packaging processes.

Importance of Hot Tack Strength in Medical Device Packaging

In medical packaging production, sealed packages may experience tension, movement, and internal pressure before the seal has fully cooled. For example, during pouch filling, transportation through packaging equipment, or product handling, weak hot seals may open prematurely.

Insufficient Hot tack-styrke can lead to:

• Seal opening during production
• Product contamination risks
• Increased packaging defects
• Reduced manufacturing efficiency

Therefore, evaluating hot tack performance is essential when developing packaging systems for medical devices, sterile barriers, and flexible packaging structures.

Den Hot Tack-test allows engineers to compare different packaging films and determine which material combinations provide better early seal resistance.

ASTM F1921 Hot Tack Test Methods and Testing Principle

ASTM F1921 describes two primary approaches for evaluating hot tack performance.

Method A: Fixed Delay Method

In Method A, the testing system measures hot tack strength at selected time intervals after the sealing jaws open. The instrument creates a relationship between seal strength and cooling time.

This method is useful for understanding how quickly a seal develops strength after sealing. It helps engineers identify the optimal balance between sealing temperature, cooling time, and production speed.

Method B: Variable Delay Method

In Method B, the operator selects a specific delay time after sealing. The instrument measures the maximum force required to separate the seal at that condition.

This method is commonly used for comparing different materials or evaluating packaging performance under specific production conditions.

Both methods provide valuable information about material behavior during the early sealing stage.

How to Perform a Hot Tack Test

A typical Hot Tack-test includes several controlled steps:

1. Prepare Test Samples

Flexible packaging films are cut into suitable strips. The samples may include identical films or different film combinations depending on the application.

2. Set Sealing Parameters

The sealing conditions are adjusted according to the material requirements:

• Tetningstemperatur
• Tetningstrykk
• Oppholdstid
• Test speed

Proper parameter control ensures reliable comparison between materials.

3. Perform Heat Sealing

The film strips are placed between heated sealing jaws. The jaws apply pressure for a defined period to create the seal.

4. Measure Seal Separation Force

After sealing, the sample is automatically pulled apart. The instrument records the force curve and calculates the maximum separation force.

5. Analyze Results

The measured Hot tack-styrke helps determine whether the material meets packaging process requirements.

Selecting a Suitable Hot Tack Tester for Medical Packaging Applications

Pålitelig Emballasje til medisinsk utstyr evaluation requires testing equipment that can accurately control sealing and pulling conditions, such as the Cell Instruments Hot Tack Tester.

By using appropriate hot tack testing equipment, packaging manufacturers can better understand seal formation behavior and improve the reliability of medical packaging systems.

Applications of Hot Tack Testing in Packaging Quality Control

Den Hot Tack-test is widely applied in:

• Medical device pouches
• Sterile barrier packaging
• Pharmaceutical flexible packaging
• Food packaging films
• High-speed form-fill-seal applications

For medical packaging manufacturers, hot tack analysis provides valuable data during material selection, process validation, and production troubleshooting.

Konklusjon

Den Hot Tack-test is an important evaluation method for understanding the early sealing performance of flexible packaging materials. Based on ASTM F1921, this test provides quantitative measurement of Hot tack-styrke, helping manufacturers evaluate whether seals can withstand mechanical stress immediately after formation.

For Emballasje til medisinsk utstyr, reliable hot tack performance is essential to maintaining package integrity and protecting product safety. Through standardized testing methods and accurate measurement systems, manufacturers can optimize sealing processes and achieve more consistent packaging quality.