Polytetramethylene Ether Glycol (PTMEG)

Polytetramethylene ether glycol (PTMEG) is a waxy, white solid that melts to a clear, colorless viscous liquid near room temperature. PTMEG is produced by the catalyzed polymerization of tetrahydrofuran (THF). The chief uses of PTMEG are in the production of spandex fibers, polyurethane elastomers, and copolyester-ether elastomers.

The three largest global PTMEG producers—BASF, Dairen Chemical Corporation and Mitsubishi Chemical—together account for 64% of world capacity in early 2013. INVISTA was the fourth-largest producer and remains a major consumer of PTMEG, but in lieu of constructing new plants following the capacity reduction in Western Europe, the company began licensing its process technology to producers in China in exchange for long-term supply agreements. All of the major producers have made investments in China.

China currently accounts for more than 40% of the global capacity and more than 50% of global consumption, but only about 30% of the global production. Not surprisingly, the majority of new plants and capacity expansions will take place in China, to supply the country's rapidly growing market for spandex.

The following pie chart shows world consumption of PTMEG:

Asia, excluding Japan, accounted for nearly 70% of the total consumption of PTMEG in 2012, because the region is a major producer of spandex. By 2017, Asia, excluding Japan, will account for nearly three-fourths of the total global consumption of PTMEG.

Spandex is the largest end use for PTMEG, accounting for more than 70% of global demand annually. (The generic term spandex is used in the United States while the term elastane is used in Europe.) This elastomeric fiber is used mainly in apparel, including undergarments, hosiery and athletic outfits, as well as in baby diapers, bandages, and home furnishings. PTMEG demand for spandex is expected to increase at about 6% per year through 2017.

Polyurethanes are produced mainly from polyols and diisocyanates, where the polyol portion (in this case, PTMEG) forms the soft segment, while the diisocyanate provides the hard segment. PTMEG is used for thermoplastic polyurethane (TPU) and cast urethane elastomers, and in urethane adhesives, sealants and surface coatings. Together, these polyurethanes accounted for about 18% of PTMEG consumption in 2012. PTMEG-based urethanes offer resistance to hydrolysis and fungus, flexibility at low temperatures, low heat buildup, high resiliency, low viscosity and very low noise characteristics, making them suitable for such diverse markets as automotive hoses and gaskets, forklift tires, roller skate wheels, industrial belts, tank and pipe liners, shoes (e.g., athletic shoes), and medical prostheses, catheters and other medical devices.

Copolyester-ether elastomers (COPE) are high-performance engineering materials that bridge the gap between the more flexible elastomers and the rigid plastics. COPE are relatively easy to process, resistant to oil and many chemicals, and have low-temperature-flexibility characteristics. COPE are used in many automotive applications, such as seating, airbag deployment, air intake ducts, hoses and tubing, as well as in breathable films for medical applications.

After INVISTA shut its Western European PTMEG plant in 2010, the global supply situation tightened and prices rebounded from the lows during the economic downturn on strong demand recovery. Prices continued to rise in 2011 due to supply shortages from intermittent production outages for the precursor 1,4-butanediol (BDO). In 2012, BASF increased its total global PTMEG capacity to 250 thousand metric tons, after which the price increases moderated.

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