Published August 2015
Diisocyanates and polyisocyanates are reactive intermediates characterized by terminal isocyanate groups, which typically are reacted with the hydroxyl groups of polyol coreactants to form polyurethanes. The most widely used diisocyanates and polyisocyanates are aromatic in their composition. A product mixture of polymethylenepolyphenylene isocyanate (also called polymeric MDI or PMDI) and p,p′-methylene diphenyl diisocyanate (MDI) is derived from aniline (via benzene). Toluene diisocyanate (TDI, also called tolylenediisocyanate) is derived from toluene.
The major producers of diisocyanates and polyisocyanates are Bayer MaterialScience, Wanhua Chemicals, BASF, Hunstman, and Dow Chemical USA. Together, these five producers accounted for 82% of the total world capacity for diisocyanates in 2014.
The following pie charts show world consumption of TDI and MDI:
Future growth for MDI is expected to be slightly higher than GDP growth, while TDI growth will approximate GDP growth. As domestic demand for MDI and TDI has slowed in recent years, some of the major producers have shut down older facilities (sometimes in conjunction with the addition of new plant capacity) and increased export volumes to the faster-growing regions of the world such as the Pacific Rim, South America, and Central and Eastern Europe. In addition, most major producers have a worldwide presence—production facilities and/or joint ventures in North America, Western Europe, Japan, and other regions of the world.
The development of efficient gas-phase TDI technology and the start-up of world-scale Middle Eastern TDI and MDI plants will lead to the continued shutdown of old and/or small production facilities around the world.
TDI and MDI markets are expanding and China is now the largest consumer of TDI and MDI. Markets will continue to expand in developing countries in Asia, especially India and Southeast Asia.