Lab techs and line workers call it zippering when a crack starts at an edge and runs along the bondline with almost no resistance. It is typical of brittle adhesives in peel, of tapes with weak anchorage and of joints that were never well wetted. A test curve that drops off a cliff after the first peak usually matches a zippered sample.
Got it started with a fingernail and the whole strip zippered right off, no fight at all.
Also heard as
- zipper
- unzipping
- zip
Related terms
Peel
The force needed to strip a flexible bonded layer off a surface, given per unit width.
Peel stress
Tension pulling one adherend away from the other at the edge of a bond, concentrated along a thin line.
Adhesive failure
A break at the interface between adhesive and part, leaving one surface clean or nearly clean.
Toughened
Describing an adhesive modified with rubber or soft particles so the bond resists cracking, peel and impact.