Key takeaways
- The Certificate of Analysis is the producer's formal statement of what was in a batch — the most important document in the box, and the first thing a quality adjuster pulls in a dispute.
- Every CoA must show producer/plant/reactor train, lot and silo, production date, tested MFI (with method and weight), density or K-value, the additive package, compliance statements, and package counts.
- Run three checks before release: match the spec window, match the package count to the bill of lading, and match each lot to its silo.
- Never accept verbal reassurance on an out-of-window CoA — get a replacement lot or a written deviation note. A clean CoA file is cheaper than insurance.
Every shipment of polymer arrives with a Certificate of Analysis. It is the single most important document in the box — more important than the packing list, more important than the bill of lading. It is the producer’s formal statement of what was actually in that batch when it left the silo.
Most procurement teams treat the CoA as a filing requirement. They scan it and forward it. That is a missed opportunity, because every CoA dispute starts with something that was on the page from day one.
- Producer name, plant, and reactor train (or grade designation that uniquely identifies the train)
- Lot number and silo number
- Production date — not the date the CoA was printed
- Tested MFI (or MFR), with method and weight — see our MFI primer
- Density (for polyolefins) or K-value (for PVC) or molecular weight indicator
- Additive package summary — antioxidant, slip, antiblock, UV stabiliser
- Compliance statements — REACH and RoHS for EU shipments, FDA food-contact where relevant
- Net weight per package and total package count
First, match the spec window. The order said MFI 0.9–1.1; the CoA says 0.95. That passes. The order said MFI 0.9–1.1; the CoA says 1.15. That fails. Do not accept verbal reassurances on out-of-window CoAs — either get a replacement lot or a written deviation note from the producer.
Second, match the package count. Standard PE/PP packaging is 25 kg bags on a 1.0–1.05 MT pallet, with 40–42 pallets in a 40-foot container. PVC powder typically ships in 1.0 MT FIBC bags, 20 per container. If the CoA shows a package count that does not match the bill of lading, somebody has miscounted.
Third, match the lot to the silo. Real producers test every silo, not every package. That means a single shipment can carry CoAs from two or three lots — each silo discharge is its own analysis. If the CoA shows one lot covering twenty pallets that arrived from two silos, the document was generated by accounting, not by the lab.
When a buyer downstream files a quality claim, the first thing every adjuster pulls is the CoA. If the CoA on file shows an out-of-window MFI that nobody flagged at intake, the claim almost always settles against the buyer. The dispute is not about whether the polymer was bad — it is about whether the buyer accepted bad polymer in writing.
A clean CoA file is cheaper than insurance. We treat it as a standard checkpoint before payment is released under documentary collection or LC, and recommend buyers apply the same discipline internally.
Frequently asked
Questions on the desk
What is a polymer Certificate of Analysis (CoA)?
A CoA is the producer's formal, batch-level statement of what was actually in a shipment when it left the silo — tested MFI, density or K-value, additives and compliance statements. It is the single most important document in the box, more so than the packing list or bill of lading.
What should I check on a CoA before accepting a polymer shipment?
Three things: (1) the tested values fall inside the order's spec window; (2) the package count matches the bill of lading; and (3) each lot maps to a silo — producers test per silo, so a real shipment may carry two or three lots.
What if the CoA's MFI is outside the order's spec window?
It fails — get a replacement lot or a written deviation note from the producer; do not accept verbal reassurance. If a downstream quality claim is filed and the CoA on file shows an out-of-window value nobody flagged, the claim almost always settles against the buyer.
Why does one shipment carry multiple CoAs?
Real producers test every silo, not every package, so a single container can carry CoAs from two or three lots — each silo discharge is its own analysis. One lot 'covering' material from two silos is a sign the document was generated by accounting, not the lab.
General market commentary from the OmniaStrata desk, provided for information only. It is not legal, financial, tax, or trading advice, and it is not an offer or a commitment to any terms. Figures such as price ranges, spreads, financing costs, and credit periods are illustrative market context, not OmniaStrata's rates or terms. Actual contract terms — including price, payment instrument, credit, insurance, and Incoterms — are agreed in writing on a per-transaction basis and at OmniaStrata's discretion. Market conditions change; figures reflect the publication date.