Polyurethanes (abbreviated to PU or PUR) are a group of plastics which, depending on the starting compounds, feature a broad variety of properties.
Common to all of them is a reaction between two monomers, a higher-percentage alcohol (polyol), and an isocyanate. Polyurethanes were first discovered in 1937 through polyaddition. PU plastics are most commonly used for foams, e.g. cleaning sponges, mattresses, and construction foams, but are also used as varnishes and adhesives. Owing to their broad spectrum of properties, they are an ideal material for product design.