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.