Sourcing hydroxyl silicone fluids from China
Hydroxyl-terminated silicone fluids from China carry 0% to 6% UK duty. The named hydroxy-terminated dimethyl siloxane grade has a suspension; ordinary grades pay 6%. Match the chemistry and viscosity to the tariff description, and check chemical supply duties before sale. Cambridge China Bridge sources hydroxyl-terminated silicone fluids.
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6% duty, with a named zero-duty grade
Read from the UK Trade Tariff on 1 October 2026, heading 3910 covers silicones in primary forms. Hydroxy-terminated dimethyl siloxane with viscosity of 38 to 100 mPa·s falls under 3910 00 00 45, with a 6% base duty and a 0% suspension. The suspension excludes mixtures, preparations and multicomponent products containing the listed polymer. Other hydroxyl fluids generally fall under 3910 00 00 90 at 6%; its named suspensions do not cover ordinary hydroxyl fluids.
No anti-dumping measure is recorded. The tariff attaches import and export waste controls. For material shipped as waste under notification controls, consent from the dispatch, destination and transit authorities is needed before shipment. For a China shipment, ask your customs broker to confirm the applicable waste procedure before ordering recovered or discarded material.
The table distinguishes grades sharing the residual code. Confirm the composition, end groups and viscosity using our commodity code guide. Finished sealants need separate classification. See the vinyl-terminated silicone fluids guide for related products within the heading.
| Goods | Commodity code | Duty | Anti-dumping or countervailing duty on China |
|---|---|---|---|
| Hydroxy-terminated dimethyl siloxane, viscosity 38 to 100 mPa·s | 3910 00 00 45 | 6% | None |
| Hydroxyl-terminated silicone fluids below the named viscosity range | 3910 00 00 90 | 6% | None |
Specify hydroxyl content and viscosity together
Specify hydroxyl-terminated chemistry rather than accepting a generic silicone oil description. Agree viscosity and its test temperature, hydroxyl content and its reporting basis, volatile content, residual cyclic siloxanes, appearance and permitted additives. State whether the fluid is unblended or supplied with solvent, filler or other components.
Trial the sample in your intended condensation-cure formulation. Record the crosslinker, catalyst, mixing method and cure conditions so repeat batches can be compared. Agree sealed drum packing, storage conditions and batch-specific certificates of analysis.
Confirm with HSE whether UK REACH registration requirements or exemptions apply to the polymer, monomers and additives. Check the importer's UK REACH position and request the safety data sheet. Before sale in Great Britain, ensure correct chemical labelling and packaging; review the hazard classification against the actual composition.
Worked duty example
Illustrative example, not a quote: Illustrative order: 5 tonnes of hydroxyl-terminated silicone fluid outside the named suspension, in drums under 3910 00 00 90, invoiced at £17,000 free on board, with £1,400 of freight and insurance to the UK. The customs value is £18,400. Duty at 6% is £1,104. Import VAT at 20% is charged on the customs value plus duty, £19,504, so it is £3,900.80. Import taxes total £5,004.80; a VAT-registered importer can usually reclaim the VAT, so the lasting cost is the £1,104 of duty. The import duty and VAT guide explains each step.
Inspection checklist
Identity: match the drum grade and batch number to the order, certificate of analysis and retained sample; confirm hydroxyl termination.
Viscosity: test a representative sample at the agreed temperature and compare it with the approved grade.
Reactivity: check hydroxyl content and run the agreed cure trial; compare cure behaviour and the cured sample with the approved formulation.
Packing: check seals, leaks, contamination and lot labels on arrival; compare volatile and residual cyclic results with the purchase specification.
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What goes wrong
A fluid can match the viscosity specification yet have different hydroxyl content, changing its behaviour in the buyer's formulation. Generic silicone oil can be substituted for the reactive grade. Excess volatiles, contamination or leaking drums can undermine an otherwise acceptable certificate.
Another failure is claiming the suspension from the words 'hydroxy-terminated' alone. Check the complete tariff description and mixture exclusion. Keep shipment samples and batch records, and use quality inspection to agree the checks before dispatch.
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 hydroxyl silicone fluids from China?
Generally 6%. The named hydroxy-terminated dimethyl siloxane grade at 38 to 100 mPa·s under 3910 00 00 45 has a 0% suspension, subject to its description and exclusions. No anti-dumping measure is recorded.
Does every hydroxyl-terminated silicone fluid qualify for zero duty?
No. Match the chemistry and viscosity to the named description.
What should I ask the factory to test?
Ask for viscosity at an agreed temperature, hydroxyl content, volatile content and residual cyclic siloxanes. Trial the batch in your own cure formulation and retain a sample.
Does hydroxyl silicone fluid need UK REACH registration?
Ask HSE to confirm the registration requirements or exemptions for the polymer, monomers and additives. Check the composition and your importer position rather than relying on a generic supplier statement.