ISO 11339

What Is ISO 11339 Hot Tack Testing?

Hot tack is the ability of a heat seal to resist stress immediately after sealing, before it has cooled to ambient temperature. ISO 11339 measures this by sealing a sample under defined conditions — temperature, dwell time, and pressure — and separating the seal within a controlled delay time after sealing. The peak force measured during separation indicates how well the package will hold on high-speed filling lines before the seal has fully set.

Hot tack is distinct from seal strength, which measures the final cooled bond. Both properties are critical to packaging qualification — ISO 11339 addresses the most time-sensitive phase of the sealing window and is particularly relevant for vertical and horizontal form-fill-seal applications where packages are filled and moved before seals have cooled.

J&B Hot Tack Tester for ISO 11339

The J&B Hot Tack Tester automates the sealing and peel sequence required by ISO 11339. Sealing temperature, dwell time, sealing pressure, delay time, and peel speed are all programmable — allowing labs to replicate production conditions and compare results across material formulations and processing parameters. Results are delivered as peak force and a full force-displacement profile.

Contact our team to discuss your ISO 11339 testing requirements or Request a quote for the J&B Hot Tack Tester.