History

Otto Bayer and his coworkers at IG Farben in Leverkusen, Germany, first made polyurethanes in 1937.The new polymers had some advantages over existing plastics that were made by polymerizing olefins or by polycondensation, and were not covered by patents obtained by Wallace Carothers on polyester.Early work focused on the production of fibres and flexible foams and PUs were applied on a limited scale as aircraft coating during World War II.

Polyisocyanates became commercially available in 1952, and production of flexible polyurethane foam began in 1954 using toluene diisocyanate (TDI) and polyester polyols. These materials were also used to produce rigid foams, gum rubber, and elastomers. Linear fibers were produced from hexamethylene diisocyanate (HDI) and 1,4-butanediol (BDO).