The types you will be quoted
Recycled pellets are sold by polymer family, and each has a distinct source stream and market.
- rPET — from bottles; the most mature stream, food-grade available through approved processes.
- rHDPE — from milk and detergent bottles; rigid, high-volume, well-established pricing.
- rLDPE — from film; sensitive to contamination, best quality from industrial collection.
- rPP — from caps, crates and automotive; wide property range depending on the source.
- Mixed polyolefin / PolyAl — blended PE/PP streams, sometimes with mineral or metal content; lowest cost per kilo, excellent for durable moulded goods.
The four numbers that decide whether it runs
Melt flow index is the single most important. It tells you how the melt will behave on your tool, and drift between batches is what causes short shots, flash and scrap. Ask for the tested MFI per batch, not a range on a marketing sheet.
Density identifies the polymer and reveals filler content. Ash content quantifies the inorganic load directly — mineral filler, metal, pigment. Moisture matters because polyolefins absorb little but pellets carry surface water; excess causes splay and voids. Together these four define processability far better than the polymer name.
Batch homogeneity: the quality issue nobody quotes
Most recycled-pellet complaints are not about the specification being wrong. They are about the specification being right on average and wrong in detail: a supplier blends feedstock from several sources, the average hits the datasheet, and your mould sees a different material every few hours.
Ask a direct question: how large is a homogeneous batch, and is it produced from a single feedstock source? A supplier who processes in defined lots — for example 60-tonne batches from one source stream — is giving you something structurally different from one who blends continuously. This is worth more than a slightly better headline MFI.
Certification, traceability and regulation
Post-consumer recycled content is what regulators count. The EU Packaging and Packaging Waste Regulation sets binding recycled-content targets, and CSRD/ESRS E1 reporting makes purchased materials part of a company's Scope 3 category 1 inventory. Your customers will increasingly ask you for evidence, not a claim.
Practical checklist: a certificate of analysis per batch, a stated recycled-content percentage, origin traceability, a relevant product standard where one exists (for example UNE 53925:2026 for recycled polyolefins from cartons), and — if the claim is going into a sustainability report — a product carbon footprint calculated to a recognised method.
What drives the price
Recycled pellet pricing is set by feedstock scarcity, processing cost and the virgin resin market. When virgin polyolefin prices fall, recyclate loses its cost advantage and marginal recyclers idle capacity — which is why recycled pricing is volatile in a way buyers often do not anticipate.
Levers you control: accept a darker or unspecified colour, accept a wider MFI window, order in full-batch quantities rather than part loads, and commit to a contract rather than spot buying. Each of those materially reduces price. Materials from a stable, non-kerbside source stream also tend to price more predictably because their supply is decoupled from consumer collection rates.
What to request from any supplier
| Certificate of analysis | Per batch, with tested values not ranges |
|---|---|
| Melt flow index | Tested value and test conditions (e.g. 190 °C / 2.16 kg) |
| Density | kg/m³, to identify polymer and filler load |
| Ash content | Quantifies inorganic content directly |
| Moisture | Especially relevant for washed streams |
| Recycled content | Stated %, post-consumer vs post-industrial |
| Batch size | How large is a homogeneous lot? |
| Traceability | Documented origin of the feedstock |
| Standard | Applicable product standard, e.g. UNE 53925:2026 |
| Carbon footprint | PCF to a recognised method, for Scope 3 reporting |