Every shipment of resin we sell comes with a certificate of analysis for the batch. It is issued with the shipping documents, and it is what turns a specification into a measured result.

What it covers

The certificate reports the grade, the grade level and the published indicators for that specific batch. For an SG5 premium order, that means the viscosity number, the impurity count, the volatile matter, the apparent density, the sieve fractions, the fish eye figure and the residual vinyl chloride figure.

It is a batch document. It is not a type declaration and it is not a marketing sheet — it tells you what was in the container you just received.

What to do with it

Compare against the specification, not against the last delivery. The specification is the band. What matters is that the certificate falls inside the band for the grade level you ordered.

If it does not — and this is rare — do not feed the line first and check later. Raise it before you run the batch.

Check the grade and grade level match the order. This sounds obvious, but a mismatch here is the single most expensive clerical error in the whole process, and it is easy to make when a buyer is working from several suppliers' paperwork at once.

Keep the certificate with the batch records. If you raise a claim later, it is the reference that ties the material in the container to the figures you are disputing.

If the figures do not match

Photograph the bags, keep the batch number, and contact us in writing before you feed the line.

Claims relating to quality must be raised in writing within 30 days of the date of discharge, quoting the batch number and the container or waybill reference. Claims outside that window cannot be entertained. That is a standard term and it appears on the quotation, but it is worth knowing before you need it rather than after.

Check the material physically as well

The certificate is a laboratory result. A physical check on arrival catches the things a certificate cannot:

  • Colour — the powder should be white. Off-white or yellowing suggests contamination or degradation.
  • Odour — a sharp or musty smell means it has been somewhere hot or damp.
  • Free flowing — it should pour. Caked material has absorbed moisture.
  • Beads — hard translucent beads are pre-existing fusion defects. They will show up as specks in your product and they cannot be screened out.

Do this on arrival, not at the point of use. The window for a claim is short.

And keep the records

Batch number, certificate, quantity received and the date of discharge. If you are running a quality system, this is the traceability trail, and it is much cheaper to build as you go than to reconstruct afterwards.

Send us your specification and we will state what the certificate covers for that grade and grade level on the quotation.