This research assessed the impact of light-weighting plastic bottles on the sorting and recycling stages.

Key findings

  • The report concluded that overall thin packaging was no more difficult to sort and recycle than thick packaging. However, it did identify that for rigid PET bottles there was a minimum thickness of 0.05mm, but this thickness was only present in less than 2% of the sample.
  • The most important thing for effective sorting and recycling was how the bottles were presented; reaffirming that a bottle should be presented as empty and flattened with the lid on.

To determine what impact light weighting has had on the recycling process, feedback has been obtained from 11 different materials recycling facilities (MRFs) and six plastics recycling facilities (PRFs).

As well as obtaining qualitative feedback, sampling from three MRFs (two lots of sampling on PET bottles and one on HDPE) and two PRFs (both recycling PET) was carried out.

All MRFs felt that thin packaging was not more difficult to recover than thicker packaging. The most important thing for effective recovery is the presentation of the material to the Near Infrared (NIR) sorters. Packaging should be flattened to enable effective sorting as this creates a more stable area for ejection using air jets. If the material is round it can roll on belts leading to a loss in efficiency during sorting.

The sampling from the MRFs showed that the thin material was recovered to the product stream effectively and from a sorting point of view there is unlikely to be the need for a minimum thickness specification.

Surveys of the UK PRFs also suggested there was no negative impact from light weighting, however sampling and analysis was carried out at two PET PRFs.

Read the full report here.

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  • WRAP-Minimum thickness of plastic bottles to be recycled summary report.pdf

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