Sourcing OBSH blowing agent from China
OBSH blowing agent from China has a 6% UK base duty, suspended to 0% for the qualifying substance. The suspension excludes mixtures and preparations. Confirm the composition and UK REACH position before importing into Great Britain. Cambridge China Bridge sources OBSH blowing agent.
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OBSH duty and the suspension
Read from the UK Trade Tariff on 5 October 2026, heading 2935 covers sulphonamides. Its OBSH line is 2935 90 90 50, naming 4,4'-oxydi(benzenesulphonohydrazide), CAS 80-51-3. The table repeats this commodity line for different purchase specifications. For other substances, see the sulphonamides guide.
For goods from China, the supplied tariff record shows a 6% base duty and an autonomous suspension to 0%, with no anti-dumping or countervailing duty recorded. The suspension excludes mixtures, preparations and products made up of different components containing OBSH. Do not assume an OBSH blend or carrier-based preparation qualifies for the same treatment.
The UK Trade Tariff attaches export-control entries for dangerous chemicals and waste. Ask your customs broker to confirm their relevance to the proposed import from China. For England, waste shipment controls apply only where the material is waste. Confirm the commodity code using the chemical identity and full composition before shipment.
| Goods | Commodity code | Duty | Anti-dumping or countervailing duty on China |
|---|---|---|---|
| Unblended OBSH blowing-agent powder | 2935 90 90 50 | 6% | None |
Specify OBSH for your foaming process
Specify the chemical identity, assay, impurities, moisture, particle-size distribution and whether the material contains any carrier or other additive. Agree gas-yield and decomposition tests, including the test method and sample conditioning. Request a batch certificate of analysis and trial the sample in your own compound and process before approving production.
For imports into Great Britain, ask HSE to confirm whether UK REACH registration is required for the substance and your annual import quantity, and whether an exemption applies. Establish the registration position before ordering. Labels and packaging must be correct before market supply. A safety data sheet is required if the chemical is hazardous and supplied for use at work.
Agree sealed moisture-resistant packing, batch identification and storage instructions supported by the supplier's safety information. Use testing and certification support to turn the agreed specification into a sampling and test brief.
Worked duty example
Illustrative example, not a quote: 5 tonnes of unblended OBSH powder, illustrative order under 2935 90 90 50, invoiced at £21,000 free on board, with £2,500 of freight and insurance to the UK. The customs value is £23,500. Duty at 6% is £1,410. Import VAT at 20% is charged on the customs value plus duty, £24,910, so it is £4,982. Import taxes total £6,392; a VAT-registered importer can usually reclaim the VAT, so the lasting cost is the £1,410 of duty. The import duty and VAT guide explains each step.
Inspection checklist
Identity: match the invoice, container labels, certificate of analysis and safety data sheet to the ordered substance and batch; investigate any undeclared additives.
Powder: check seals, moisture ingress, caking, contamination and appearance against the approved sample.
Performance: independently check assay, moisture, particle size, gas yield and decomposition behaviour using the agreed methods.
Process trial: compare dispersion, foam density, cell structure and surface finish with the approved result before releasing the batch.
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What goes wrong
A matching trade name can hide a different composition or particle-size distribution. A batch may meet its assay target yet disperse differently or give an unacceptable foam structure. Treat caking, inconsistent test methods and a changed certificate format as reasons to investigate before use.
A prepared blend can also undermine a suspension claim made for the named substance. Settle composition, tariff treatment and the chemical compliance position before shipment, and retain representative samples for comparison. See quality inspection explained.
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.
Frequently asked questions
What is the UK import duty on OBSH from China?
The supplied tariff record shows 6% base duty, suspended to 0% for qualifying OBSH under 2935 90 90 50. The suspension excludes mixtures and preparations. No anti-dumping or countervailing duty is recorded.
Does an OBSH blend qualify for the duty suspension?
Give your broker the full composition before agreeing the classification and duty treatment.
Do I need UK REACH registration for OBSH?
Confirm the registration position for your supply before ordering.
What should I test before accepting an OBSH batch?
Check identity, assay, moisture, particle size, gas yield and decomposition behaviour against agreed methods. Trial the material in your compound and compare dispersion and foam structure with the approved sample.