Meaning
Polymer material classification designating polyethylene recovered from post-consumer waste streams that has undergone collection, sorting, washing, and re-pelletization for re-use in plastic conversion operations. Specifying post-consumer recycled polyethylene allows packaging manufacturers to meet circular economy targets while reducing reliance on fossil-based virgin polyolefins. The material designation applies strictly to polyolefins collected after consumer use, distinguishing it from industrial scrap or internal plant regrind.
Rheological Drift
Multiple heat histories during initial converting, consumer use, and re-extrusion induce chain scission and crosslinking within the polymer backbone. Melt flow index values fluctuate markedly across different post-consumer recycled polyethylene lots, complicating injection molding process repeatability. Variable crosslinking increases shear sensitivity, leading to melt fracture and uneven wall thickness in blown film lines.
Molders compensate by adjusting barrel temperature profiles or installing dynamic melt pressure control valves to maintain steady injection speeds.
Property Modification
Contamination from polypropylene or environmental degradation reduces environmental stress crack resistance and tensile elongation at break. Converters blend post-consumer resin with high-performance virgin grades or add specialized elastomer impact modifiers to restore mechanical specifications. Masterbatch additives stabilize residual antioxidants to prevent yellowing during secondary processing steps.
Economic Impact
Cleaning and sorting costs keep high-purity recycled grades priced close to virgin resin index rates. Processing scrap rates increase when raw material contamination levels trigger filter screen pack clogging. Converters balance recycled content percentages against potential mold downtime costs.
