Polyurethane

Polyurethane is any polymer from organic parts, connected by urethane links. It's usually made from a diisocyanate and a polyol (more than one OH groups) - e.g. polyethylene glycol.

Specific properties depend on the compounds used. Where does it appear? Sofas or other furniture can be made of it. Sports equipment. It can be used as isolation material. Plastic parts in buildings. It's even used as a glue in one of its forms. Myself, I became interested in it because of skates wheels - it resists more pressure than rubber or some metal alloys (my wheels endured for nearly a year, despite frequent usage). It's resistant to oils and solvents and bad weather. It endures both high and low temperatures. And it's quite cheap.
The underlying idea was invented in 1937 and since then the material has found many different applications.