Using PCR can be a sound technical and environmental decision, but only if the project validates the real variability of the material that will run in the press.
Key idea: PCR risk is not only the recycled percentage, but batch-to-batch dispersion and how that dispersion affects the moulded part.
PCR is not a property, it is a source
Two PCR batches with the same commercial name can have different thermal history, composition, moisture, colour, contamination or MFI. A datasheet approval is therefore not enough.
What variables should be checked
Review MFI/MFR, moisture, contamination, colour stability, odour, black specks, dimensional dispersion and minimum mechanical behaviour. Demanding applications may also require ageing or regulatory checks.
Why the prototype must use the real material
If production will mould PCR, validation with virgin material confirms something else. The prototype must show how the actual recycled material fills, packs, replicates texture and holds tolerances.
What to document for series
Supplier and lot, PCR percentage, available certificates, drying parameters, MFI/MFR, process conditions, observed defects, retained parts and acceptance criteria.
| PCR risk | What to observe in prototype |
|---|---|
| MFI/MFR variation | Filling, pressure, flash, short shots and process window |
| Contamination | Black specks, inclusions, odour and surface defects |
| Thermal degradation | Brittleness, colour, odour and property loss |
| Colour variability | Visual homogeneity and appearance acceptance |
Frequently asked questions about PCR material
Why does PCR need specific validation?
PCR can vary in flow, moisture, colour, contamination and mechanical properties. That variability affects filling, finish, tolerances and process stability.
Is virgin material validation enough if series will use PCR?
Only as an initial reference. If series uses PCR, the prototype should test the intended recycled material or a representative sample of its variability.
What should be documented in a PCR prototype?
Supplier, batch, recycled content, drying, MFI/MFR, process parameters, observed defects and acceptance criteria.
Technical sources checked
- ISO 1133-1:2022: method for determining melt mass-flow rate (MFR) and melt volume-flow rate (MVR) of thermoplastics.
- ISO 15270:2008: guidelines for the recovery and recycling of plastics waste.
- ISO 15343:2007: traceability of plastics recycling and assessment of recycled content.
These sources support flow-rate measurement, recycled-material management and PCR-content traceability. Final acceptance should be verified with representative lots and processing conditions.