Sourcing hexamethylene diisocyanate from China

Pure HDI pays 6% duty

Read from the UK Trade Tariff on 1 October 2026, heading 2929 covers compounds with other nitrogen function. Pure HDI falls within the other-isocyanates line, 2929 10 00 90, carrying 6% duty for goods from China. No anti-dumping or countervailing measure is recorded. The line has a named-substance suspension to 0%, but pure HDI is not covered. The table repeats this tariff line for different purchasing uses of the same monomer.

The supplied tariff record attaches an export control for waste to this line. Environment Agency guidance for England says waste shipment controls apply only when the material is waste. For a shipment from China described as waste, or whose status is uncertain, confirm the applicable requirements with your customs broker before ordering.

Keep pure HDI separate from HDI-based polymers and formulated hardeners when checking classification. Supply the full composition and product identity to your broker and confirm the commodity code. See the wider isocyanates guide for neighbouring substances.

Specify HDI monomer and batch acceptance

Write down that the order is for pure HDI monomer. Agree purity, isocyanate-group content, moisture, acidity, hydrolysable chlorine, colour and the test methods used for acceptance. Request a certificate of analysis for each batch. Specify sealed, dry packing, storage conditions and remaining shelf life, then assess a sample in your own formulation.

For Great Britain, confirm your UK REACH registration responsibilities and any only-representative coverage with HSE before importing. Diisocyanates are respiratory and skin sensitisers. Chemicals must be labelled and packaged correctly before market supply, and hazardous chemicals supplied for workplace use need a safety data sheet. Information, instruction and training are required for people working with isocyanates; ask HSE to confirm the applicable workplace exposure-control requirements.

Worked duty example

Illustrative example, not a quote: One tonne of pure HDI monomer in drums, illustrative order under 2929 10 00 90, invoiced at £4,000 free on board, with £2,500 of freight and insurance to the UK. The customs value is £6,500. Duty at 6% is £390. Import VAT at 20% is charged on the customs value plus duty, £6,890, so it is £1,378. Import taxes total £1,768; a VAT-registered importer can usually reclaim the VAT, so the lasting cost is the £390 of duty. The import duty and VAT guide explains each step.

Inspection checklist

Identity: match the order, drum labels and batch certificate to pure HDI monomer; check that a formulated hardener has not been substituted.

Analysis: compare batch results with agreed purity, isocyanate-group content, moisture, acidity, hydrolysable chlorine and colour limits; arrange independent testing where needed.

Packing: inspect seals, closures, corrosion, leaks and batch identification; compare storage and journey records with the agreed conditions.

Documents: check the English safety data sheet, chemical labels and registration coverage against the actual supplier and substance before release. Use the inspection guide to plan checks.

What goes wrong

Moisture entering isocyanate packaging can form urea solids. For HDI, treat sediment, damaged seals and unexplained changes in batch results as reasons to hold the material for assessment. A sample that performs in the buyer's formulation is more useful than accepting a supplier's generic grade description.

Another failure is treating an HDI-based hardener as pure monomer, or claiming a suspension intended for a different named isocyanate. Match composition, batch documents and the declaration before shipment. Keep disputed drums separate while the supplier and an independent laboratory establish whether they meet the purchase specification.

Cambridge China Bridge sources these products for UK businesses, checking the factory and the documents before shipment. See factory verification. For repeat volumes, see container programmes.