Chemical profile: US TDI

29 November 2013 09:36 Source:ICIS Chemical Business

The main use for toluene di-isocyanate (TDI) is in the manufacture of polyurethane (PU) flexible foams. These foams are used in upholstery, mattresses and automotive seats. Other uses for TDI include PU coatings, adhesives, sealants and elastomers.

PU elastomers are used in more demanding applications thanks to their toughness, flexibility, strength, abrasion resistance, shock absorbency and chemical resistance.

PU coatings are one of the fastest growing sectors of the paints and coatings industry despite their relatively high cost because they have good durability, resistance to corrosion and abrasion, and flexibility.

The TDI market in the US is expected to remain stable to soft through December on seasonality, as industry participants manage inventories to reduce tax exposure at year-end. However, industry sources noted satisfaction with TDI demand growth in automotive applications.

US October 2013 auto sales increased by 11% year on year and were 8.4% higher year to date, according to US-based automotive data firm AutoData.

US October auto sales of passenger cars and light trucks were more than 1.21m units, up from 1.09m units for the same month a year ago. Year-to-date US auto sales were at 12.99m units, up by 8% from 11.99m units through October 2012. For comparison, auto sales in October 2010 were at 950,165 units.

A maintenance turnaround at Bayer MaterialScience’s TDI production facility in Baytown, Texas, in March 2013 caused little disruption in TDI availability in the US.

At the same time, Latin America was adequately supplied because the region had already learned to work with Asian imports after Dow Chemical closed its TDI production facilities in Freeport, Texas, US, and in Camacari, Brazil.

TDI capacity in the Americas totals 407,500 tonnes/year, 16% of current global capacity of around 2.48m tonnes/year. No new projects are projected for the Americas, while a total of 1.39m tonnes/year of new capacities are planned in China, Germany and Poland.

In the second quarter of 2010, Dow permanently closed its TDI production plant in Freeport because production at that site was no longer economically viable. The Freeport facility was Dow’s only US-based TDI plant. It had a capacity of 105,000 tonnes/year, as assessed by ICIS.

Market participants are projecting steady pricing into the first quarter of 2014 on balanced supply and demand of TDI and feedstock toluene in North America.

Bulk TDI prices were assessed by ICIS on 20 November at 152-167 cents/lb ($3,351-3,682/tonne, €2,482-2,727/tonne) DEL (delivered), down by 4 cents/lb from October, with implementation subject to contract terms. Some participants had already implemented TDI decreases in October or earlier, while others continued under negotiation, sources said.

TDI has two isomers: 2,4-TDI and 2,6-TDI. The most common form of TDI offered commercially is an 80/20 mixture of the 2,4- and 2,6-isomers, but it is also available as a 65/35 mixture and as a pure 2,4-isomer.

The main commercial route for manufacturing TDI starts with the nitration of toluene using nitric acid. The resulting dinitrotoluene is converted by catalytic hydrogenation to toluene diamine, which is then dissolved in an inert solvent and reacted with phosgene to produce a crude TDI solution. The crude solution is fractionated to remove any unreacted phosgene, solvent and hydrogen chloride before being distilled under vacuum.

Bayer developed a phosgenation route that is carried out in a gas phase instead of a liquid phase, which reduces the amount of solvents by 80% and the amount of energy used by around 40%. Bayer has said the investment costs are thus 20% lower.

TDI can also be produced directly from dinitrotoluene through a liquid phase carbonylation process, which avoids the use of phosgene and some waste recovery problems.

In addition, one-step processes have been developed, but not commercialised, based on the reaction between dinitrotoulene and carbon monoxide.

The direction for the flexible PU foam market in 2014 is expected to follow the trend of 2013, in line with moderate demand amid the gradual yet bumpy economic recovery, industry participants said.

Demand for TDI is projected to continue improving in 2014 in line with the US economic recovery and especially with growth in the automotive sector. Market participants have noted healthy TDI consumption with increasing car sales in 2013.

Additionally, the preference for a more comfortable ride implies greater PU usage in each automobile. TDI applications in the bedding and furniture sectors are expected to grow at a moderate pace, according to industry participants.

However, seasonal buying patterns result in slowing demand for downstream products as well as for TDI towards the end of the year, market participants said. Additional demand softening is anticipated as holiday gift-giving toward the end of the year takes precedence over new bedding and furniture purchases. Meanwhile, the automotive sector remains steady on buying interest for new car models.

By Ron Coifman