procurement · supplier comparison · China sourcing
How to Compare PU Sealant Suppliers in China
By the Tech Department · Reviewed by Wang · Updated 2026-11-14 · How these notes are made
Comparing suppliers is not a price spreadsheet. Two quotations can look identical and describe different products, different evidence and different risk. Use a fixed comparison sheet so the commercial and technical answers are visible side by side.
1. Define the same requirement
Write the substrate, joint width, movement, application temperature, cure conditions, pack format, label language and destination market before requesting prices. Ask every supplier to quote against that requirement and to state any deviation.
If a supplier proposes a different model, treat it as an alternative, not as the same quote. Record the model, the reason for the change and the property that is different.
2. Compare technical fit
Ask for the four-column test table: property, standard, typical value and method. Then ask which values are measured on every batch and which are catalogue typicals. A tensile number without a method or conditioning temperature is not comparable.
For a windscreen adhesive, the relevant questions include skin time, cure rate, tensile, elongation, shear and the vehicle maker’s drive-away requirement. For a construction joint, movement class, recovery, adhesion and water pressure matter more than the highest tensile figure. For wood, solids, viscosity, clamp time and moisture tolerance decide the result.
3. Compare evidence, not claims
Use the same evidence hierarchy for each supplier:
| Evidence | Why it matters |
|---|---|
| TDS with methods | Shows what the number means |
| Batch record with measured result | Shows process control, not just a catalogue |
| Certificate of analysis matched to carton | Links the document to the goods |
| SDS and transport classification | Prevents a freight surprise |
| Retention sample | Lets you retest after a dispute |
A supplier who can provide these without a special project is easier to qualify. A supplier who can only provide a certificate without a batch number is giving you a document, not traceability.
4. Compare the landed cost
Build the landed cost from FOB or CIF, freight, insurance, duty, VAT, port charges, inland delivery, inspection, bank charges and the cost of holding safety stock. Add the cost of a failed batch: replacement, freight, downtime and customer credit.
A cheaper cartridge with a higher reject rate is not cheaper. A barrel that requires a different pump or a sausage that cannot be used in your existing gun is not a like-for-like pack.
5. Compare communication and change control
Send one technical question before the quotation and see whether the answer is specific. Ask what happens if a raw material changes, a batch is out of specification or a label needs correction. A supplier who answers with a process is easier to work with than one who answers with a promise.
Check the response time in your time zone, the named contact and whether the person who answers technical questions is the same person who will handle the order. A fast sales reply that cannot answer a method question is not technical support.
6. A simple weighted comparison
| Criterion | Suggested weight | What to score |
|---|---|---|
| Technical fit | 30% | Model, test table, sample result |
| Batch evidence | 20% | Record, COA, traceability |
| Landed cost | 20% | Total cost, not FOB alone |
| Quality system | 10% | Calibration, deviation, change control |
| Commercial terms | 10% | MOQ, payment, lead time, warranty |
| Communication | 10% | Specific answers, named contact |
The weights are a starting point; change them for your project. A supplier can win on price and still fail the technical-fit threshold. Do not average a fail into a pass.
7. Common comparison mistakes
- Comparing a private-label quote with a stock-label quote.
- Comparing a 310 ml cartridge with a 600 ml sausage without converting the cost per litre.
- Accepting a certificate that names a different legal entity.
- Testing a sample that did not come from the intended production site.
- Ignoring the cost of a batch that fails at the customer, not at the factory.
The practical position
Shortlist two or three suppliers, give them the same requirement, and compare the evidence behind the number. The winner should be the supplier whose product, batch record and commercial terms you can defend to your own customer — not simply the one with the lowest first invoice.