Start with the polymer and the application
A description such as black regrind or natural pellet is a starting point, rather than a complete specification. Two materials can look similar while having different polymer compositions, origins and processing characteristics. Establish what the material is and what the next manufacturing process needs before comparing its presentation.
Mechanical recycling can involve sorting, size reduction, washing, separation and extrusion. The sequence and extent of treatment depend on the incoming stream and the intended output. A material name should therefore be accompanied by a description of the processing it has actually received.
Regrind and flakes
Regrind generally describes plastic reduced in size by grinding or granulation. Flakes are smaller pieces produced through size reduction, a term often used for bottle and film materials. These descriptions can overlap in commercial use, so agree the particle-size range and presentation instead of relying on the name alone.
Ask whether the material has been sorted, washed and dried, and whether different colours or polymer grades have been combined. Photographs can explain the form, but they cannot establish composition or hidden contamination. An irregular fragment can be a useful input for a suitable process; its suitability still needs to be assessed against the receiving equipment and product requirements.
Pellets
Recycled pellets are formed after material is melted, extruded and cut. Depending on the process, the melt may also be filtered and the formulation adjusted. Pelletisation describes a processing step; it does not automatically establish a particular purity, recycled-content percentage or performance level.
Request the relevant grade information, including polymer type, colour, origin and any agreed property limits. Describe your feeding and storage arrangements too. A change of material form may affect how your production team handles a delivery, even when the underlying polymer family stays the same.
Compare the complete material brief
For an effective comparison, give each proposed material the same set of questions. Use a consistent enquiry brief to compare its identity, presentation, history and relevant properties.
Where a new material is being considered, agree the sampling, trial and acceptance steps before a production order. The useful choice is the form that fits the application and the evidence available for the batch, rather than the form with the most polished appearance.
- Polymer family, grade and known source.
- Particle or pellet size, colour and packaging.
- Sorting, washing, drying and melt-processing history.
- Contamination limits and relevant property data.
- Quantity, delivery requirements and intended processing route.