Hot Viscosity Testing FAQ - ASTM F1921

What is Hot Tack Testing?

The hot tack test is a way to determine the strength of a heat seal while it is still hot. Heat sealing is commonly used in flexible packaging, especially to ensure an airtight seal for products that need to remain fresh and free from contamination. This means it is especially important to the food industry, but it is used in many other industries as well.

To which ASTM standard does the hot tack test conform?

Hot tack testing can be done in accordance with ASTM F1921, a standard test method for evaluating heat seal strength of packaging materials. For the test to qualify, it needs to be applied immediately after the seal is complete, and before it has had a chance to cool to room temperature.

How to verify hot tack test?

Hot tack testing is validated by measuring the seal's ability to withstand force. This is important in determining the ability of a seal to withstand the weight and pressure it will withstand during its service life. The temperature range for hot tack was also measured, so performance could be verified over a range of different heats.

What other types of seal strength tests are there?

There are several other types of seal strength testing that are well suited for flexible packaging. Some important ones include tensile strength testing and burst or creep testing, both of which can help you determine how your seal will perform under various conditions.