Home / Resources / How to measure hot tack of a hot melt using the DuPont spring test
How to measure hot tack of a hot melt using the DuPont spring test
Hot tack is cohesion while the seal is still hot. The DuPont spring test screens EVA/wax blends before you burn time on a form-fill machine. Call 800-249-0337.
Preview · about 1 minute
Plant-floor overview. Unlock below for the full converter checklist.
Form-fill machinery needs hot tack: the coating must hold while it is still hot so the air blast that keeps the tube open, or the weight of the drop, does not open the bond before it cools. DuPont's Sales Technical Laboratory built this spring test for blends of EVA vinyl resins and wax. It is a lab screen. Final choice still belongs on the packaging machine.
You get (1) maximum bond while the seal is hot and (2) the jaw-temperature and dwell window. A wider window is easier to run. Figure 3-4 in the original PDF shows medium, high, and ultra-high hot-tack profiles.
A 0.4 oz/in spring best matched Mira-Pak 8000 and 9000 series packagers and Wright / Woodman Fleet-Weigh machines. A 0.6 oz/in spring was closer to Mira-Pak 5000 B or Woodman Profit Maker.
What's in this guide
- Equipment
- Procedure
- Calibrate the spring
General plant guidance only — not a substitute for your process, SDS/TDS, or line trials. Call 800-249-0337 to match a grade.