Hotmelt

Hot melt adhesives, often called hot glue, are thermoplastic adhesives supplied as solid pellets or sticks that melt when heated and form a bond as they cool. They are applied in the molten state with handheld guns or larger extrusion equipment and set rapidly, enabling fast assembly across many industries. They bond a wide range of substrates, including wood, paper, textiles, metal and certain plastics, with minimal odor and without solvents.

Most non-reactive hot melts use polymers such as ethylene‑vinyl acetate (EVA), polyolefins, or polyamides, combined with tackifiers, waxes and plasticizers to adjust viscosity and flexibility. Reactive hot melts (one- and two-component polyurethane systems) cure through moisture exposure to form crosslinked networks, improving heat resistance and bond strength. Rubber-modified formulations provide improved tack and peel strength.

Processing temperatures typically range from about 120 to 180 degrees Celsius, depending on formulation. They bond on brief contact, with bond quality depending on substrate cleanliness and surface energy. Heat resistance varies: most standard non-reactive melts soften at modest temperatures, while reactive melts can tolerate higher service temperatures.

Applications include packaging and carton sealing, woodworking, bookbinding, textile assembly, electronics, automotive interiors and general product assembly. Equipment includes handheld glue guns, cartridge systems, and high-throughput extrusion or drum-melters.

Advantages of hot melts include fast fixture, solvent-free formulation, simplicity of use, and compatibility with many substrates. Limitations include limited long-term heat resistance, potential for surface staining or workpiece deformation, and sensitivity to oily or very smooth surfaces; some formulations require surface pretreatment for optimal adhesion.