A good specialty chemical specification describes what the product is for, then sets chemical limits, performance tests, packing, labels, documents and rules for change. Every limit needs a named test method.
Tie the specification to a reference sample from an approved batch. Then both sides can check later lots against something physical, not just words on paper.
What to include
- The product description and intended use, such as "non-ionic wetting agent for cotton pretreatment".
- Identity details, including chemical type, CAS numbers where relevant and ionic nature.
- Chemical and physical limits, such as active content, solids, pH, viscosity, water, colour and impurities, each with a method.
- Performance tests that mirror your process, with pass limits measured against the reference sample.
- Packing details, including pack type, size, material, closure, pallets and labels.
- Documents per batch, including the certificate of analysis, safety data sheet and any regulatory statements.
- Shelf life and storage conditions, plus the minimum remaining shelf life on arrival.
- A change notification rule, so the supplier must tell you before changing raw materials, process or plant.
Setting the limits
Start from your current product's data and your trial results. Set a range for each figure that your process can tolerate, not just the supplier's normal range. Too tight a limit raises cost and causes rejections. Too loose a limit lets weak batches through.
Separate critical limits from those that are only for information. A critical limit, such as active content, means rejection if it fails. An information figure, such as odour, is tracked and discussed but does not stop a shipment on its own. Saying which is which avoids arguments later.
State test methods precisely. A viscosity of "500 to 800 cP" means little without the instrument, spindle, speed and temperature. A pH means little without the dilution. Where possible, use ISO, ASTM, EN or other recognised methods.
Choose the certificate tests from this list. The usual set is in tests on a specialty chemical COA.
Compliance and contract
Add the regulatory requirements for your market, such as REACH status, restricted substances, biodegradability or food-contact statements. The importer usually carries these duties, so confirm the list with your regulator or a compliance adviser.
Attach the specification to your purchase contract and refer to it in every order. The contract should say what happens if a lot fails, including retesting, rejection and replacement. See what a chemical purchase contract should include.
Give the specification a version number and date. When you change it, send the new version to the supplier and get written acceptance before the next order.
Next step
We help you turn your current product data into a written specification, agree it with shortlisted plants and test lots against it. Book a free sourcing review.