Using Recycled Content – Supply Chain Project

Progress update (August 2020)

Valuable insights gained from an ambitious first trial

The aim of this trial was to incorporate as much recycled LDPE and LLDPE, recovered from agricultural film, as possible into products produced using rotational moulding. Products manufactured using rotational moulding are commonly hard-wearing, durable plastics. Incorporating a significant proportion of recycled agricultural film is challenging due to the level of contamination, characteristics of LDPE and the technical specifications that the new products must meet.

One tonne of material, comprised of 50% crop cover (made from LDPE) and 50% silage wrap (made from LLDPE), was pre-washed to reduce contamination levels and then reprocessed. Despite technical challenges with milling different grades of recycled polymer, the LDPE / LLDPE blend was successfully transformed into an 800 µm powder of suitable quality for use in the rotational moulding process.

Our environmental assessment revealed that the estimated carbon emissions associated with this recycled material stand at just 20% compared to virgin polymer. Whilst an economic assessment showed that recycled polymers could provide a cost-effective alternative.

The powder was used to manufacture a product made of 100% recycled content. However, its surface was rough and pitted with ‘pin holes’. The reason is believed to be the low Melt Flow Index (MFI) of the molten polyethylene (PE) – it was too viscous to flow evenly into the mould.

Despite the 100% recycled content not meeting the product specifications, this ambitious trial has provided valuable insights. The successful milling of the recycled PE and the positive environmental and economic benefits of using it warrant further investigation. As a next step, we plan to test a blend of recycled and virgin PE powders to increase the MFI. Our aim will be to demonstrate that a suitable product can be produced using at least 20% of the recycled powder, which would still represent a cost-saving to the moulder and reduce the carbon footprint of the product.
Back to Supply Chain Demonstration Projects