Comparing the automatic hot tack tester with the Dupont spring test method

Cold peel after the seal has cooled does not tell you what happens on the line. The seal is often loaded while it is still hot. Hot tack is that still-hot strength. Food companies, converters, film producers, and resin plants use it to tighten the heat-seal cycle and to screen new structures.

Two shop-floor screens are common: the falling-weight test and the DuPont spring test. Both put a fixed load on a hot seal. The answer is peel or no-peel. They are hard to run the same way twice and they do not give a force number. A tensile hot-tack tester is meant to fill that gap.