Even to the trained eye it is impossible to tell the difference between a clear PVC and PET flake, so when Evolve Polymers challenged TOMRA to sort the 'impossible' to a new level of purity, the foundations were laid for a partnership that would result in a world first for plastics sorting.
- To develop a world-class solution allowing the sorting of PET flake by material and colour simultaneously, providing a milestone in the quality and purity of the PET output (to be measured in parts per million rather than percentage)
- To create a 'super yield' - minimizing oversorting while maintaining output purity
Evolve Polymers is the UK's leading reprocessor of plastic recyclable materials and 20 of TOMRA’s units are already used to sort mixed plastics from UK MRFs at its Hemswell Plant (opened in 2010). Following this successful installation, Evolve Polymers called on TOMRA Sorting once again to provide the technology to deliver a consistent yield of super-clean recycled PET. The Hemswell Plant sorts plastics by colour and polymer, followed by washing and extruding the PET into Food Grade rPET pellet, but as customer demands changed, Evolve Polymers sought levels of purity significantly higher than the current industry standard.
Brian Gist, Sales Engineer at TOMRA Sorting, explains more: "As you increase the levels of recycled content in plastic packaging the purity of that content becomes increasingly more important. If levels of PVC contamination are significant enough, it can affect the package's integrity and its ability to be fit for purpose. Many of Evolve Polymers´ customers had clear recycled content targets and we had to work with Evolve Polymers to ensure the sorting systems we put in place could deliver a consistent, super clean rPET supply with minimum wastage."
Initially approached in late 2010, TOMRA Sorting immediately initiated a R&D project to create the technology capable of meeting the challenge of creating a super yield of PET with unparalleled purity levels. TOMRA Sorting´s engineers worked with Evolve Polymers over the course of a year to enhance AUTOSORT FLAKE system to do just that.
Brian explains; "While many in our industry would say that the purity levels demanded by Evolve Polymers couldn't be achieved, we faced the challenge head on. We redesigned software and hardware and spent a significant number of man hours getting to grips with the challenge to understand how we could make the impossible possible.
"We worked closely with Evolve Polymers throughout the journey to give them the confidence that the TOMRA machines could deliver. In October 2011, Evolve Polymers ordered five of our AUTOSORT FLAKE systems, which are capable of sorting flakes down to 2mm while still maintaining the high levels of purity and minimising wastage."
The AUTOSORT FLAKE systems have been incorporated into the Hemswell Plant, after material has been identified, shredded and then washed. Subsequently, the washed flake is sorted by size, before the AUTOSORT FLAKE remove any impurities. The system is based on TOMRA Sorting’s bespoke spectrometer technology that delivers outstanding results on standard sorting applications across the world.
“We are very pleased with the standard that TOMRA Sorting has been able to achieve."
Evolve Polymers’ co-founder comments: “We are very pleased with the standard that TOMRA Sorting has been able to achieve. Previously the industry has not been able to sort PET flake to this very high standard of quality and purity. This development will help us to supply our extrusion equipment and all out PET flake customers with the highest quality material available in the market today.”
This industry milestone has been possible thanks to the strong working relationship between Evolve Polymers and TOMRA Sorting. Brian Gist concludes: “This is a great example of two businesses working together to produce exceptional results. Evolve Polymers had a clear understanding of what they wanted to achieve and were very supportive throughout the process. We had to make a step change in the scale of measurement from percentage purity to parts per million but we took on the challenge and are very pleased with the results and the world-class standard that has been set.”