Hot melts are heated in a tank or gun to roughly 120 to 200 C and dispensed as beads, dots or sprays. They set in seconds as they cool, which suits high-speed carton sealing, product assembly, bookbinding and nonwovens. Common bases are EVA, polyolefins and polyamides. Because they soften again when heated, standard hot melts have limited heat resistance and creep under load.
Case sealer's dropping flaps, check the hot melt temperature and the open time before you blame the board.
Running a hot melt tank hotter to fix poor bonding usually trades one problem for char; check open time and compression first.
Also heard as
- hot-melt adhesive
- HMA
Related terms
PUR
Polyurethane reactive hot melt, applied molten like a hot melt, then moisture-cured into a heat-resistant bond.
Open time
The longest gap allowed between applying adhesive and closing the joint while it can still wet the second part.
Angel hair
Fine threads of hot melt that string off the nozzle and drift across machines and products.
Char
Dark, degraded hot melt that builds up in tanks and hoses from long time at temperature.
Hot glue
Floor and craft name for hot melt adhesive, especially sticks fed through a handheld gun.