The forerunner of hot melt adhesive was the utilization of molten wax for bonding purposes. Molten wax gave way to a much more efficient and superior way to bond everything from tennis shoes to the construction of aircraft. The first hot melt adhesive developed was ethylene vinyl acetate copolymers or EVA. This copolymer is compatible with paraffin. Since then, numerous hot melts have been created. Among them are styrene-isoprene-styrene (SIS copolymers), styrene-butadiene-styrene (SBS copolymers), and ethylene ethyl acrylate copolymers (EEA).
These types of hot melts are mixed with a variety of plasticizers, waxes, and resins that maximize and enhance their performance. The newest hot melt adhesive is polyurethane reactive or (PUR). This polymer is cured in a different way than the others. It sets up much more rapidly, in mere seconds, and then is rigid in a matter of minutes. Because of this fact, PUR hot melt is particularly useful in manufacturing, where it is applied at small connection points, thereby eliminating the use of nails, snaps, screws, or clips. In general, hot melt applications form a strong bond quickly and are not affected by water or humidity as are other thermoplastic polymers. New, innovative, and various hot melt adhesives will undoubtedly continue to be created.