Published June 2016
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 (polyurethane) fibers, polyurethane elastomers, and copolyester-ether elastomers.
The two largest global PTMEG producers—BASF and Dairen Chemical Corporation—together accounted for 49% of world capacity by the end of 2015. INVISTA was the fourth-largest producer in 2012 and remains a major consumer of PTMEG, but in lieu of constructing new plants following the capacity reduction in Western Europe, the company has licensed its process technology to producers in China in exchange for long-term supply agreements. All of the major producers have made investments in China.
The majority of new plants and capacity expansions have taken place in China, to supply the country's rapidly growing market for spandex. Chinese PTMEG production capacity doubled between 2012 and 2015. China currently accounts for about 59% of global capacity, about 57% of global consumption, and about 48% of global production.
The following pie chart shows world consumption of PTMEG:
Asia, including China and Japan, accounted for nearly three-fourths of the world consumption of PTMEG in 2015, because the region is a major producer of spandex. Asia will account for nearly 80% of the total global consumption of PTMEG by 2020.
Spandex is the largest end use for PTMEG, accounting for more than 70% of global demand annually. 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 an average rate of 5.0–5.5% per year through 2020.
Polyurethanes are produced mainly from polyols and diisocyanates, where the polyol portion (in this case, PTMEG) forms the soft segment and 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 16% of PTMEG consumption in 2015. 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.
Demand for PTMEG in China is expected to grow at an average rate of about 7% annually through 2020, driven primarily by rapidly increasing demand for spandex fibers. Consumption in other Asian countries is expected to grow at 1–2% annually during the forecast period.
PTMEG consumption in the United States is expected to grow by only 1% per year on average through 2020. Latin American consumption is forecast to grow at an average annual rate of about 3%.
With raw material prices having declined in recent years and ample PTMEG supply, PTMEG prices in most regions have fallen since 2013.