Sourcing isocyanates, TDI and MDI from China

6% duty, with TDI suspended

Read from the UK Trade Tariff on 27 September 2026, heading 2929 covers compounds with other nitrogen function: isocyanates in subheading 2929 10, and other compounds such as sodium cyclamate and phosphoric triamides in 2929 90. All 16 lines carried 6% on goods from China except sodium cyclamate at 0%, with no anti-dumping measure.

The residual isocyanate line (2929 10 00 90) has a 0% suspension to 31 December 2028 for named substances only: TDI as an 80/20 mixture of the 2,4- and 2,6-isomers, methyl-m-phenylene diisocyanate of 99.5% purity or more, 1,3-bis(isocyanatomethyl)benzene (XDI), bis(isocyanatomethyl)bicycloheptane (NBDI), 1,5-naphthylene diisocyanate of 90% or more, and 3,3'-dimethylbiphenyl diisocyanate (TODI). XDI and NBDI of the purities named in their own lines (2929 10 00 35 and 2929 10 00 45) pay 6%, as does ethyl isocyanate. Butyl isocyanate, trimethylhexamethylene diisocyanate and two other listed isocyanates have their own 0% lines. Pure MDI and HDI are not listed, so they pay 6%.

Polymeric MDI and other isocyanate-based polymers fall under heading 3909, and polyurethane systems are preparations, so confirm the commodity code.

Sensitisers, COSHH, REACH and transport

Under GB CLP, retained Regulation (EC) No 1272/2008, diisocyanates such as TDI and MDI are classified as respiratory and skin sensitisers, and TDI is also acutely toxic by inhalation. Users must control exposure under the Control of Substances Hazardous to Health Regulations 2002, and a GB importer of one tonne or more a year must register under UK REACH, retained Regulation (EC) No 1907/2006, or use an only representative.

TDI is a dangerous good for transport (UN 2078, toxic), so it needs approved drums or tank containers and a dangerous goods declaration. MDI freezes and can form insoluble dimer if stored too warm or too cold, so agree storage and transport temperatures.

Specifying isocyanates

Specify the product (TDI 80/20, pure MDI, HDI and so on), NCO content, isomer ratio, hydrolysable chlorine, acidity, colour, dimer content for MDI, packing (nitrogen-blanketed drums, IBCs or ISO tanks), storage temperature range, shelf life and a certificate of analysis per lot.

Worked duty example

Suppose, purely for illustration, you import 20 tonnes of pure (monomeric) MDI under 2929 10 00 90. At £44,000 free on board and £4,000 to ship and insure, the customs value is £48,000. Pure MDI at 6% pay £2,880 of duty; VAT is then worked out on value plus duty, £50,880, giving £10,176. Of the £13,056 paid at import, only the £2,880 of duty stays a cost for a VAT-registered business. The method is set out in how UK import duty and VAT work.

Inspection checklist

Documents: check the certificate of analysis against the specification, the isomer ratio or purity that decides the suspension, and the English safety data sheet.

Laboratory: test NCO content, isomer ratio, acidity and hydrolysable chlorine on an independent sample, and dimer content for MDI.

Packing: check drums are sealed under dry nitrogen, labelled with GB CLP pictograms and UN numbers, and that temperature records cover the journey.

What goes wrong

Isocyanate orders fail on moisture, temperature and paperwork. Moisture gets in and forms urea solids, MDI forms dimer through poor temperature control, the isomer ratio does not match the suspension wording, and drums are not approved for the dangerous goods class.

Agree packing and temperatures in writing, test independently, and settle UK REACH first. See our quality inspection guide.

Cambridge China Bridge sources isocyanates for UK foam, coatings and adhesives makers, checking the producer's quality and packing records first. See factory verification.