Importing PU sealant from China: the eight checks

A sealant order fails at customs far more often than it fails in the joint. The eight checks below are the ones that cost the most when skipped.

1. Is it dangerous goods?

One-component moisture-curing PU sealants are generally not classified as dangerous goods when they contain no solvent and no free isocyanate above the threshold. Solvent-borne primers and activators often are. Get the SDS and the transport classification in writing before booking freight — a primer classified as flammable changes the freight rate and the route.

2. Shelf life versus transit time

Catalogue shelf life for activators and primers is six months unopened. A sea freight booking plus customs clearance can eat eight weeks. Order the activator close to production, or accept that it arrives with two-thirds of its life left.

3. Temperature in transit

Moisture-curing PU does not like heat. A container on a dock in July can exceed 60 °C, which accelerates cure inside the cartridge and shortens shelf life. Ask for shaded stowage and avoid the cheapest routing through hot transhipment ports if the goods will sit.

4. Carton counts and pallet mix

310 ml cartridges ship 12, 20 or 24 per carton depending on the model and the artwork. Sausages ship 20 per carton. A mixed pallet across models is normal for distributors, but it has to be agreed at order stage, not at loading.

5. Labelling for your market

Your market may require the label in a specific language, with a specific hazard statement or a specific responsible-person address. Sending artwork late means either a reprint or a non-compliant carton.

6. Documents

The set that usually travels with a sealant shipment: commercial invoice, packing list, bill of lading, certificate of origin, SDS, and the batch test record where the buyer’s market requires it. Ask which of these your broker needs before the goods leave, not after.

7. Incoterm and who clears what

FOB and CIF are the common starting points. CIF puts the freight and insurance on the seller but leaves clearance and duties with you; DDP puts everything on the seller and usually costs more than the service is worth on a first order.

8. Sample before the pallet

A cartridge tested in your own application is worth more than any data sheet. Test on the actual substrate, at the actual temperature, with the actual preparation method — and keep the batch number of the sample so the production batch can be traced back to it.

What heat in transit actually does

A container on a quay in direct sun can reach 60–70 °C inside. For a moisture-curing adhesive, that is not a storage condition; it is an accelerated ageing test running for weeks.

storage at 25 °C   quoted shelf life (typically 9–12 months)
storage at 35 °C   roughly half
storage at 45 °C   roughly a quarter

A container that leaves in July and sits at a hot transhipment port arrives with a fraction of its shelf life spent, and nothing on the carton records it.

Three clauses in the purchase order reduce the exposure:

1. Production date within 45 days of shipment. A fresh batch has more margin to lose.
2. Shaded stowage and a direct routing. Ask the forwarder which routing avoids the longest hot-port dwell.
3. Delivery temperature record where the value justifies a data logger — one logger per container is cheap against a rejected pallet.

None of these is standard in a first order, and all of them are cheaper than discovering the problem when the cartridges skin in the nozzle.

What to do when the goods arrive hot

Do not reject automatically. Test first:

• Cut a cartridge and inspect the product: a thick skin or a grainy texture is a bad sign.
• Measure skin time and cure rate against the certificate.
• Bond a coupon on your substrate and break it.

A batch that passed through 50 °C for two weeks may still be inside its working window; a batch that sat at 65 °C for a month probably is not. The test distinguishes them, and the record supports the claim.

The document set, by who issues it

Document	Issued by	When it is needed
Commercial invoice	Seller	Always; must match the packing list
Packing list	Seller	Always; cartons, weights, dimensions
Bill of lading	Carrier	Always; the title document for the goods
Certificate of origin	Chamber of commerce or CCPIT	Preference claims, some markets
SDS	Manufacturer	Always; customs and downstream users
Transport classification	Manufacturer or forwarder	Before booking, for primers especially
Batch test record	Manufacturer	When the buyer’s market or QA requires it
EN 15651 test report	Accredited lab	Construction sealants sold in the EU

Two of these decide whether the shipment moves: the transport classification for anything flammable, and the certificate of origin for any duty preference. Both are easier to obtain before the container is booked than after it is on the water.

What this means for buyers

1. Get the transport classification before you book freight.
2. Buy activators and primers against a production date, not a stock date.
3. Approve artwork before production starts, not after.
4. Keep the sample batch number; it is the reference for any later claim.

Where the requirements come from

• EN 15651-1 — the harmonised standard a construction sealant must be tested to before it can carry CE marking.
• ECHA Candidate List — the REACH list an SVHC declaration is written against; check the date on the declaration, not just its existence.