What is the difference between a TDS and a COA?
A Technical Data Sheet (TDS) describes a grade: its typical properties and the limits the supplier commits to. A Certificate of Analysis (COA) reports test results for one specific batch. The TDS tells you what to expect; the COA proves what you received. Professional buyers ask for both.
A Safety Data Sheet (SDS) is a third document. It covers hazards, handling, storage and transport, not performance.
What should a calcium carbonate TDS include?
| Section | What to look for | Why it matters |
|---|---|---|
| Grade name | Grade code and whether coated or uncoated | Codes are not standardised between suppliers |
| Chemical composition | CaCO₃ %, MgCO₃ %, Fe₂O₃ %, HCl-insolubles % | Purity drives whiteness and processing |
| Particle size | D50, D97 (or D98), top cut, residue on 45 µm sieve | Controls dispersion and surface finish |
| Optical | Brightness R(Y) or R457, whiteness, CIE L*a*b* | Critical for white and light-coloured products |
| Moisture | % at 105 °C | High moisture causes voids and processing defects |
| Coating (coated grades) | Stearic acid level, hydrophobicity | Shows treatment level and quality |
| Oil absorption | g/100 g | Affects resin or binder demand |
| Bulk density | Loose and tapped, g/cm³ | Feeder setting and container loading |
| Test methods | ISO, ASTM or in-house method per parameter | Without methods, numbers cannot be compared |
| Packaging and storage | Bag type, net weight, shelf life | Logistics and warehouse planning |
| Revision and date | Version number and issue date | Ensures you hold the current sheet |
Typical value vs specification limit: why does it matter?
A typical value is an average result; individual batches can fall above or below it. A specification limit (for example, "moisture ≤ 0.2%") is a commitment that every batch should meet. Contracts and incoming inspection should be built on limits, not typical values.
What should a COA show?
A useful COA identifies the grade, batch number, production date, quantity and the results for the key parameters, each against its specification limit. It should be signed or issued by the supplier's quality function and traceable to the shipment.
At CarboCore, batch codes currently follow the pattern grade + production date + sequence (for example, CC10T-261004-01), linking each COA to its bags and container.
How do you compare two suppliers' data sheets?
Compare like with like.