procurement · TDS · COA · quality
PU Sealant TDS and COA: How to Verify a Supplier
By the Tech Department · Reviewed by Wang · Updated 2026-11-14 · How these notes are made
A supplier can send a beautiful TDS and a signed COA in ten minutes. The verification question is whether those documents describe the material in the carton and whether the numbers can be reproduced.
1. Read the TDS as a specification, not a brochure
A usable TDS has four columns: property, standard, typical value and method. It also states the model, the test conditions and any limitations. If a page says “high strength” without a method, it is marketing copy.
Check the identity fields first: legal manufacturer, production site, product name, model and revision date. A TDS that names one company while the quotation and certificate name another is a document-control problem, even if the product is the same.
2. Read the COA as a batch record
The COA should identify:
| Field | Why it matters |
|---|---|
| Model and product name | Confirms the material |
| Batch number | Links paper to carton |
| Production and test date | Shows age and release timing |
| Property and method | Makes the result comparable |
| Specification limit | Defines pass or fail |
| Measured result | The actual value |
| Released by | Accountability |
If the COA shows only “conforms” without a measured value, it is an attestation, not an analysis. That may be acceptable for a non-critical property, but it is weak evidence for a safety or performance claim.
3. Match the batch in both directions
Pick a carton or drum from the delivery and find its batch number. Then ask the supplier to show the COA for that batch. Reverse the test: take a COA and ask which cartons or pallets it covers. If either direction fails, the document chain is broken.
Record the batch number on your receiving document and keep a retained sample. If a customer complains six months later, the sample and COA are the evidence you will need.
4. Check the method, not just the number
A tensile result is not comparable if one supplier uses GB/T 528 and another reports a different specimen or speed without saying so. A skin time measured at 23 °C is not the same as one measured at 5 °C. A cure rate without temperature and humidity is incomplete.
For each headline property, ask: method, sample preparation, conditioning, test speed and acceptance range. If the answer is “our lab standard”, ask for the written procedure.
5. Common discrepancies
- COA batch number does not match the carton.
- Certificate names a different legal entity or factory.
- TDS revision is older than the product label.
- Result is outside the TDS limit but marked “pass”.
- Method is missing or replaced by a trade name.
- Certificate is undated or unsigned.
- The same COA is reused for several shipments.
Any one of these is a reason to hold the batch until the supplier provides a credible explanation.
6. A verification workflow
- Request the TDS and the COA for the exact batch before shipment.
- Compare model, legal entity and production site.
- Check the method and specification limit for each key property.
- Match the batch number to the carton or drum.
- Keep a retained sample and a copy of the documents.
- On arrival, verify the label and batch against the file.
- If a result is out of specification, quarantine the batch and ask for a deviation before use.
The practical position
The TDS tells you what the product is supposed to be. The COA tells you what this batch was measured to be. The carton tells you which batch you actually received. A supplier who can connect all three is easier to trust than one who sends only the first document.