Choosing a Hot-Melt Adhesive - EVA, PO or PUR?
Hot-melt adhesives bond fast and solvent-free, from carton sealing to structural assembly. This guide compares EVA, polyolefin and reactive PUR by open time and heat resistance and shows which applicator gun suits each adhesive.
View hot-melt adhesivesEVA, PO or PUR - which type fits?
Hot-melt adhesives ship as a solid, are melted in the equipment and set as they cool. Three base types cover almost every job: EVA (ethylene vinyl acetate) as the low-cost all-rounder, PO (polyolefin) for difficult plastics and heat, and reactive PUR for the highest final strength.
EVA and PO are physical hot-melts: in principle they can be re-melted. Reactive PUR instead cross-links chemically with airborne moisture, forming a permanent, heat- and solvent-resistant bond that no longer melts.
Why does open time decide the result?
The open time is the window between application and the point where the adhesive has cooled too far to wet the surface. It dictates how fast you must join parts and how large a component may be.
- Short open time (3‑15 s): fast carton sealing and high-volume cyclic production.
- Medium open time (15‑30 s): standard assembly with time to align small parts.
- Long open time (30‑60 s and more): large-area lamination, long seams, hand application.
- Waiting too long gives cold, non-adhering joints - reapply rather than press a chilled bead.
Besides open time, the setting time matters: it describes when the bond is firm enough to move the part on. Both values depend on bead volume, substrate temperature and room climate.
How much heat can the bond take?
Heat resistance states the temperature up to which a bond stays stable under load. It is critical when products travel in vehicles, sit in warehouses under a metal roof or enter warm processes.
Standard EVA softens in summer heat inside a van, so heat-loaded packaging and all structural bonds call for PO or PUR. Once cured, reactive PUR stays permanently firm and also resists oils and many solvents.
Which applicator gun suits the adhesive?
Adhesive and equipment form one system. The applicator gun must match the processing temperature, the supply format and the throughput, or adhesion suffers and the unit chars.
- Stick guns (7 or 12 mm): trades, repair, small runs.
- Tank units with granules: high throughput in packaging and manufacturing.
- PUR units: closed system or foil bag that keeps moisture out.
- Match nozzle and temperature to the adhesive's recommended processing range.
Frequently asked questions
What is the difference between EVA and PUR hot-melt?
EVA melts physically and can be re-melted, is cheap and fast. Reactive PUR cross-links chemically with humidity, becomes permanently firm, heat- and solvent-resistant, and no longer melts afterwards.
How do I choose the right open time?
Large areas and slow processes need a long open time of 30 to 60 seconds so you can join cleanly. High-volume cyclic lines need short open times of just a few seconds.
Which hot-melt handles heat best?
Reactive PUR often reaches over 120 °C heat resistance once cured. PO sits at 80 to 100 °C, while standard EVA is only around 60 to 70 °C and softens in summer heat.
Can I run PUR adhesive in a normal glue gun?
No. Reactive PUR cures with humidity and would char in an open tank. It needs closed systems or foil-bag units that keep moisture away.
Looking for the right hot-melt adhesive?
We supply EVA, polyolefin and reactive PUR hot-melts with matching applicators - tuned to open time, heat resistance and your application.
Three systems
EVA, PO and reactive PUR for every requirement.
Clear on heat
Heat resistance from 60 to over 120 °C documented.
Right equipment
Gun and adhesive as a matched system.
Expert advice
We help with selection and application.