Plastic scrap builds a success story

Brunel professor Jim Song has cracked one of the toughest of green challenges - turning mixed plastic waste into a marketable product - with more than a million EcoSheets, a green alternative to plywood, already sold.

Currently less than 20 per cent of post-consumer plastic waste in the UK is recycled with four million tonnes going into landfill each year and most countries have similar poor records.

Normal recycling techniques concentrate on bottles because they are relatively easy to sort and clean. Other plastics, especially those used in food packaging, are more problematic as they tend to be heavily contaminated not just with traces of food but with other materials including metal and paper. A further complication is that many different plastics are used and it’s virtually impossible to tell them apart in high volume sorting.

What Prof Song, a materials engineer, and his team discovered was that a process called Powder Impression Moulding (PIM) could be adapted to make boards with a tough outer skin and foam core out of contaminated mixed plastic waste.

The key engineering challenge was to adapt the PIM process from only being able to work with finely pulverised plastic powder to accepting coarse flakes of mixed plastic.

Solving this issue had twin advantages. Mechanically producing flakes is much more eco-friendly than using the amount of energy needed to form powders and the flakes, when melted, surround and encapsulate contaminants.

Prof Song’s process is now being used to manufacture other products from high-value shower trays to complete pick-up truck bays in the US – all from rubbish.