The mechanical resistance of a package seal to separation or failure under a specified test.
Also called: seal peel strength; peel force; heat-seal strength.
Interpreting a peel-strength result
It describes separation resistance for a specimen and test arrangement. The measured response can include an initial peak and a different force during continued peeling. A reported peak and a sustained-force statistic therefore need not answer the same question.
Specimen width, support arrangement and peel geometry affect interpretation. Compare results only after identifying the method, units, specimen location and how the force was summarised. A number without that context cannot show that two seals have equivalent behaviour.
Can a strong seal still have a leak path?
Yes. A local seal specimen can resist separation while a defect elsewhere in the seal or package material provides a leak path. Mechanical strength and leak integrity are complementary attributes, not interchangeable test results.
Opening performance also depends on what was separated or broken and how the pack was supported. A local peel specimen measures one part of that opening action.
How does cooled seal strength differ from hot tack?
Hot tack describes strength before a newly formed seal has fully cooled. A cooled-seal measurement describes a later state. If a specification only says “seal strength”, identify when the measurement is made before comparing it with another result.
To relate either result to a production sealing window, specify the material pair, package geometry and required bond outcome.