Polyurethanes

Abstract

The history of polyurethanes started in the 1930s in Germany when Otto Bayer proposed using diisocyanates and diols for preparation of macromolecules. The first commercial polyurethane, based on hexamethylene diisocyanate and butanediol, had similar properties to polyamides and is still used to make fibers for brushes. However, fast growth of the production and expanded application range started in the 1950s with the building of toluene diisocyanate (TDI) and polyester polyol plants for fiexible foams in Germany. However, the real jump in applications came with the introduction of polyether polyols in foam formulations. Further development and application of polyurethanes shifted from Europe to the USA and Japan. Today, polyurethanes are about the sixth largest polymer by consumption, right behind high volume thermoplastics, with about 6% of the market. The largest part of the urethane application is in the field of fiexible foams (about 44%), rigid foams (about 28%), while 28% are coatings, adhesives, sealants and elastomers (CASE) applications. These data are taken at a certain moment in time (1996) and vary from year to year and region to region, but they illustrate the relative consumption in different categories. Consumption of polyurethanes in different industries is the following: about 40% of PU is used in the furniture industry, 16% in transport, 13% in construction, 7% in refrigeration and about the same in coatings, 6% in the textile industry, 4% in the footwear industry and 8% for other applications. Table 1 illustrates the consumption of urethanes in the United States in 1996.