United Kingdom – Methods to detect different polymer types – such as use of fluorescent pigments and digital watermarks – offer exciting potential. However, they should be viewed as a means to safeguard recyclate quality rather than as the solution to boosting recycling rates, asserts Richard McKinlay, head of engineering & research at resource recovery specialist Axion Consulting, which is part of the UK-based Axion Group.
Meanwhile, near infrared (NIR) technology still has much ‘unexploited potential’ in terms of recovering more packaging such as polypropylene (PP) from rigid plastics, polyethylene and PP films, he suggests.
According to Axion, diversification in the plastics packaging market is leaving the established infrastructure behind. ‘NIR technology detects polymer type, which for many years was sufficient to recover high-quality PET, HDPE, LDPE film and PP – but this is changing,’ it observes.
Innovation in packaging has led to a more complex waste stream that contains many different components: for example, shifting UHT milk from recyclable HDPE bottles into opaque PET containers has a negative effect on recycling.
The growing use of PET in non-food products can lead to challenges when using recycled PET in new food packaging.
‘This shift has brought forward the need for an alternative to NIR that can sort material on more criteria, to protect existing recycling processes and drive up quality to access higher value markets,’ says McKinlay.
Several project teams, bringing together companies throughout the supply chain, are currently researching marker techniques that provide detailed information on what packaging can and cannot be recycled.