COA, MSDS, TDS: Reading the Documents That Ship With Your Order
Three documents travel with every consignment, they are routinely confused with one another, and only one of them tells you anything about the material actually in your container.
A purchase manager asks for “the certificate”. A supplier sends a technical data sheet. The material arrives, a parameter is out of range, and it turns out nobody ever tested that lot — the sheet was a general product description that would have read the same for any shipment in any year.
This is the most common documentation failure in the resin trade, and it is entirely avoidable once the three documents are properly separated.
The short version
| TDS — Technical Data Sheet | Describes the grade in general: typical properties and specification ranges. Not batch-specific. Used before you order, to decide whether the grade suits your application. |
| COA — Certificate of Analysis | Describes the actual lot you are buying: measured test results against stated limits. Batch-specific. Used to verify the consignment meets your purchase specification. |
| SDS — Safety Data Sheet | Describes hazards and handling: storage, first aid, exposure controls, transport classification. Not batch-specific. Used for workplace safety compliance and freight documentation. |
If you remember one thing: only the COA is evidence. The other two are reference documents.
The technical data sheet
A TDS describes the grade, not the shipment. For seedlac or shellac it will state crop and origin, physical form, the specification ranges the grade is sold against, solubility behaviour, storage conditions and shelf life.
Ranges are the important part. A TDS says wax content is not more than a stated percentage. It does not tell you what this lot measured. Treat it as the specification annexe to your contract — the thing your COA has to be checked against.
The TDS is also where application questions get settled early. If your end use is food-contact or pharmaceutical coating, that points to a dewaxed or bleached grade — solvent-processed material we source through specialist partners rather than produce at our own Nawada facility. Far better to establish that at the enquiry stage than after a container has moved. Our E904 guide covers the food-grade side in detail.
The certificate of analysis
The COA is the only document tied to the material in front of you. It should carry a lot or batch number matching your packing list, the date of analysis, the parameters tested, the measured results, the specification limits they are measured against, and the identity of the laboratory that did the work.
For lac products, the parameters that matter in practice:
| Colour index | How pale or dark the resin is. The most negotiated parameter, and largely a function of crop and host tree rather than processing. |
| Wax content | Whether the material is waxy or dewaxed. Determines clarity in solution and whether the film will haze. |
| Hot alcohol insolubles | Residue that will not dissolve. Directly predicts filtration load and finish quality in a coating line. |
| Volatile matter / moisture | Storage stability. High moisture invites blocking and shortens usable life. |
| Acid value | Free acid content as mg KOH per gram. Relevant to reactivity and compatibility with other components. |
| Ash | Inorganic residue — a general cleanliness indicator. |
| Life under heat / flow | How long the resin stays workable when molten. Matters for hot-melt and moulding applications. |
| Heavy metals | Lead, arsenic, mercury and cadmium in ppm. Required for food, pharmaceutical and confectionery-glazing use. |
Who ran the test is part of the result. A heavy-metals figure is only as good as the laboratory behind it. An in-house number on company letterhead is not equivalent to an accredited third-party result, and a serious QA function will treat them differently.
Our certificates come from a NABL-accredited laboratory. We run a two-tier programme: routine parameters — colour, wax, moisture, insolubles — are tested per batch, because those genuinely move lot to lot; the full heavy-metals panel is run periodically rather than per shipment, because those values are stable across material drawn from the same sourcing region. If your application requires a lot-specific heavy-metals result, say so at the enquiry stage and we will schedule the testing into the production run. It is a lead-time question, not a capability question.
The safety data sheet
The SDS — still widely called MSDS, though the GHS-aligned term has been SDS for years — follows a standard sixteen-section format covering identification, hazard classification, composition, first aid, fire-fighting, accidental release, handling and storage, exposure controls, physical and chemical properties, stability, toxicology, ecology, disposal, transport, regulatory information and revision history.
Two sections carry most of the practical weight for a lac shipment.
Section 7, handling and storage. Shellac is a thermoplastic resin. Above its softening point the granules or flakes fuse into a solid block — a commercial problem rather than a safety one, but the most common cause of a rejected consignment. Cool, dry, ventilated storage away from direct heat is not boilerplate here.
Section 14, transport information. Solid seedlac and shellac are normally not classified as dangerous goods. Alcoholic shellac solutions are a different matter — flammable liquids with their own classification and packing requirements. If you are importing a cut solution rather than dry resin, this is the section your freight forwarder needs.
One further note: finely divided organic resin dust can form a combustible atmosphere in enclosed handling. If you transfer bulk material mechanically, your own site risk assessment should account for it.
What to check before the cargo reaches customs
- Does the batch number on the COA match the packing list and the marks on the bags? If the numbers do not reconcile, the certificate is describing something else. This is the check most often skipped and most often the source of a dispute.
- Are the specification limits on the COA the ones in your purchase order? A certificate can be entirely truthful and still be measured against a looser standard than you bought against.
- Is the analysis date consistent with the production date? A certificate predating the lot it describes is not a certificate.
- Is the laboratory named, and is it accredited? For food and pharmaceutical grades this is not optional.
- Does the product description match the HS code on the invoice? Seedlac and shellac fall under HS 1301.90. A description that does not sit naturally under the declared code invites examination and delay.
- Is the certificate of origin the right one for the duty you expect? For Vietnam that means a Form AI under the ASEAN–India FTA. Without it the preferential rate is not available, and it cannot easily be retrofitted after arrival.
The rest of the shipping set
Alongside the three technical documents, a normal consignment travels with a commercial invoice, packing list, bill of lading or air waybill, certificate of origin, and — depending on payment terms — insurance and bank documents. For our Bangladesh lane the set is much the same, though cargo generally moves overland on FCA or DAP terms through the Petrapole–Benapole border rather than by sea, and the transport document differs accordingly.
When plant-health paperwork applies
Phytosanitary requirements are the genuinely variable part of this, and the honest answer is that they depend on the destination country and on the form of the material.
The distinction that drives it is plant residue. Sticklac — raw scraped material still carrying twig fragments — is far more likely to attract a phytosanitary requirement than washed seedlac or melted shellac, which have had the plant matter removed. Some destinations treat processed lac as exempt entirely; others do not.
We will not tell you what your national plant protection authority requires, because it changes and because getting it wrong is expensive. Confirm it with your customs broker before the order is placed, and tell us — issuing a phytosanitary certificate at origin is straightforward when it is planned for and awkward when it is discovered at the port.
The underlying point
Documentation in this trade is not administrative overhead. It is the only mechanism by which a claim about material quality becomes checkable by someone who has never visited the facility that produced it.
That is exactly why we send an accredited certificate with every shipment rather than a generic sheet. Anyone can describe their seedlac as clean. A batch number, a measured result and an accredited laboratory are what let you verify it before you pay for it.
See a Sample Certificate Before You Order
Send us your grade, volume and end application. You will get a firm rate, the specification we sell against, and a sample COA showing exactly what ships with the cargo.