Improving the performance of post-consumer resin feedstocks for rigid packaging applications: A pilot-scale assessment

Various market, environmental and political drivers encourage the use of more post-consumer resin (PCR) high-density polyethylene (HDPE) in rigid packaging. However, PCR HDPE performs poorly compared to virgin HDPE, particularly in blow-moulded bottles for cleaning products which often show inadequate resistance to environmental stress cracking. In this study we evaluate and compare additives representing various strategies designed to improve the mechanical performance of PCR HDPE. Two commercially available recycled HDPE PCRs were extruded with eight candidate additives and the bottle performance of the best performing blends were tested in extrusion blow moulding trials. FTIR analysis revealed polypropylene contamination in one PCR although rheology and thermal properties were very similar. The use of strain hardening modulus as a selection criterion for pilot scale trials was demonstrated. The results revealed that particulate additives may have negative effects while polyolefin additives are more likely to succeed at the pilot scale.