Tack defines PSAs and matters for contact cements and hot melts. It is measured by loop tack, where a loop of tape is lowered onto a plate and pulled off, by probe tack and by rolling ball tests. High tack helps labels and tapes grab on fast lines but can make positioning hard. Tack and peel are separate properties, and a tape can have one without much of the other.
Loop tack is way down on the new tape lot, the labels are flagging before the box leaves the line.
Also heard as
- quick stick
- initial tack
- finger tack
Do not mix it up with
- Peel: Tack is the instant grab under light contact; peel is the force needed to remove a bond after it has formed.
Related terms
PSA
Pressure-sensitive adhesive, the always-tacky layer on tapes and labels that bonds under finger pressure with no cure step.
Grab
Floor word for how quickly and firmly an adhesive takes hold when parts are pressed together.
Tackifier
A resin added to rubber or acrylic adhesives to raise their tack and peel.
Aggressive
Describing a tape or adhesive with high tack and strong immediate grab that is hard to reposition.