Hotmelt adhesives are thermoplastics that are applied in a molten state and form a bond on cooling to a solid state. Because hotmelt adhesives are applied in melt form and achieve their bond strength on resolidification on cooling, there are two important physical properties: glass transition temperature and melt temperature, varying significantly depending on the type of base polymer used and the additives or modifiers present in the formulation.

Generally, most hotmelt adhesives and hotmelt sealants have a glass transition temperature below room temperature. The melt temperature should be low enough to conveniently provide for application but not so high as to result in a safety or fire issue.

Today's industrial hotmelts are based on modern polymers and depending on the polymer’s properties, end applications are numerous as hot melt adhesives are very versatile, and are capable of bonding many different materials: major application areas include shoe, automotive, packaging, electrical / electronic, and woodworking.