Covestro has taken a process to recycle the PU flexible foam from used mattresses, developed in collaboration with eight other partners within the scope of the EU-funded PUReSmart-project, to the next level, it has announced. With the recent commissioning of a pilot plant, established to verify the positive laboratory results achieved to date, the company plans to further optimise the process and develop products and applications on a small industrial scale.
Thermoset polyurethane products - flexible or rigid, long-lasting, durable foams - are among the most-used plastic materials around the world. While suitable for a host of different applications, recycling them is a challenge. PUReSmart project, which brought together nine participants from six countries aimed to tackle this issue, ultimately to transform PU into a circular material.
The process differs from other PU recycling technologies, in that it allows the recovery of both main PU components: the polyol; and the primary product of the other component formed during recyling – isocyanate.
"The project is part of a long-term strategic program to fully align Covestro with the circular economy and be a driving force in value creation," said Dr. Klaus Schäfer, CTO at Covestro.
Each mattress contains on average 15-20 kilograms of foam. The development of the recycling technology, proving that polyurethanes are rcyclable, and the investment in the pilot plant are further milestones to close material loops, he said.
The first phase is to focus on process development for polyol recycling, followed by the recovery of TDA as a precursor to TDI, scheduled to start this summer.
"Our goal is to industrialize chemical recycling processes for post-consumer flexible foams in order to ultimately commercialise both raw materials derived from the recycling of mattress foam," explained Karin Clauberg, Venture Manager Flexible Foam Chemolysis at Covestro. "With our innovative technology we aim to deliver a high purity, high quality recycled polyol that fulfills customer specifications, and a recycled toluene diamine, or TDA, which is suitable for further processing to toluene diisocyanate. This isocyanate, or TDI for short, is used together with the polyol for the production of flexible foams."
Another aim of the PUReSmart research project was the development of ‘smart sorting’ technology to create a validated and cost effective PU sorting platform that could efficiently separate the different PU foams from post-consumer mattresses. Covestro, in collaboration with Recticel and Redwave – a division of Wolfgang Binder GmbH has developed software that uses machine-learning algorithms for a proper recognition of the different types of foam, enabling clean material inputs for the subsequent recycling process.