Polyurethane (PUR and PU) is a polymer composed of organic units joined by carbamate (urethane) links. Polyurethane polymers are formed by reaction of a di- or polyisocyanate with a polyol. Both the isocyanates and polyols used to make polyurethanes contain, on average, two or more functional groups per molecule. PURs have attracted attention because they can be made into rigid foams with good thermal insulation properties; elastomers, which are strong and flexible; coatings, adhesives and sealants; spandex fibers; and hard plastics used in molded products such as skateboard wheels, kitchen utensils, etc.
The term “polyurethane” was coined in 1937 by German chemist Otto Bayer who discovered the material while working for IG Farben. The new substance was first manufactured as Rigid PUR Foam and Flexible PUR Foam. It was initially used commercially as an insulating material for refrigerators during World War II, but its major breakthrough came shortly after when it began being used as upholstery foam in airplane seats. Spandex fiber followed in 1950, bringing comfortable stretchable garments to consumers worldwide.