What are Hot Melt Adhesives?

Also known by the more common name of "hot glue", hot melt adhesives are a kind of thermoplastic (a material that is solid in normal conditions, and plastic, or moldable, under heat.) These qualities make them a popular choice in product assembly for quickly and strongly bonding materials together – even highly dissimilar ones.

What are hot melt adhesives used for?

Hot melt adhesives are commonly found in a rather wide range of industrial and consumer products – including uses as widespread as the sealing of paperboard and fiberboard boxes, the assembly of plastic children's toys, and the fabrication of delicate electronic components. A hot melt applicator can be anything from a custom-built spray nozzle designed for factories, to a simple arts-and-crafts hot glue gun intended for schoolchildren.

What are the advantages (or disadvantages) of hot melt adhesives?

The excellent mold-ability of melted plastics makes them great for gap filling and flexible in usage. They boast a long and stable shelf life, and are environmentally responsible with no toxic chemical runoff or vaporization.

One major selling point of hot melt adhesives is that (unlike water-based adhesives) they don't weaken when exposed to humidity – in fact, this is the original reason for their development. They're a perfect choice for tightly bonding two non-porous surfaces – a scenario which might otherwise be problematic as moisture (potentially) builds between them.

One drawback that can make hot melt adhesives unsuitable for certain applications is that, as you might imagine, they don't hold up well under extreme heat – they will melt rather easily, and lose both form and bond strength. Know the conditions your product can reasonably be expected to submit to, and determine if hot melt adhesives are the ideal pick.