Invented back in the 1930s by Professor Dr. Otto Bayer, Polyurethane (PU) or urethane is an elastomeric material available in a wide range of hardness from eraser soft to cricket ball hard. There are different types of polyurethanes, used in a diversity of products from coatings and adhesives to shoe soles and mining components. However, the basic chemistry of each type is essentially the same.
Widespread use of polyurethanes was first seen during World War II, when they were utilised as a replacement for rubber, which at the time was expensive and hard to obtain.