Can polyurethane become a truly sustainable material? Nine companies in six European countries are collaborating in what is known as the PureSmart project to explore whether this could be achieved. One of these is Redwave, a division of BT-Wolfgang Binder GmbH and supplier of sorting and waste treatment plants, with special expertise in sensor-based technology.
The PureSmart project, which kicked off in January 2019, will run for four years, during which new methods, technologies and approaches will be studied with the aim of transforming polyurethane (PU) into a truly circular material.
Polyurethane, after all, is a thermoset polymer. The PU foams used in mattresses and upholstery are difficult to recycle and therefore tend to end up in landfill or being incinerated.
The PureSmart project, says Katharina Ander, a member of the R&D team from Redwave participating in the initiative, is targeting the recovery of over 90% of end-of-life PU with the goal of converting it into valuable inputs for new and known products. The ultimate goal is to ‘merge the durability of thermosets with the circularity of thermoplastics’.
The role of Redwave, says Ander, is to find new sorting solutions to recover materials that are currently not being recycled. To that end, smart sorting technologies to separate a diverse range of PU materials into their dedicated feedstocks and a chemolysis technology that allows the revalorisation of PU’s building blocks are being developed.
Not only will PU foams be recovered from existing waste streams, but the company is also working to separate the foams into sub-groups depending on their chemical composition. These will then be used as input fraction for the following chemical recycling processes., reducing demand for primary raw materials and minimising the volumes being landfilled.
“Within the PUReSmart project we are testing different sensors to find the best solution to differentiate the PU foams,” says Ander.
“Thanks to the broad chemical knowledge of the consortium, we have a solid database. At the end of the project, our technology will be able to sort the end-of-life PU foams into different fractions. These fractions will subsequently be fed to either chemical or mechanical recycling processes. And of course, we are aiming high: Despite the large volume of the foams, we want to be able to handle high feed rates to make PU recycling economically feasible.”