Pull Strength: Pull Strength (平拉强力)
The maximum force a closed zipper withstands when pulled apart in the tape plane, perpendicular to the chain. It is a core indicator for load-bearing openings such as bags, tents and seat covers. Pull strength depends on tape tensile, stitch quality, tooth engagement and slider retention. Testing follows standards such as ASTM D2061 and QB/T 2173, using a tensile machine with defined specimen length and speed.