Focus on sustainability: On the way to a closed loop for PU mattresses

Now that the Europe-wide research project “PUReSmart” has come to an end, Covestro and the leading company Recticel have been able to demonstrate that the two main raw materials originally used in flexible polyurethane (PU) foam from mattresses can be recovered by chemical means to a high level of quality and purity. For the first time, a flexible foam sample has now been produced from fully recycled polyol and toluene diisocyanate (TDI), respectively. Both raw materials were obtained in Covestro’s pilot plant in Leverkusen.

“With this we have fully achieved the goal of developing a technology to chemically recycle these products and convert polyurethane into a high-quality recycled material,” says Bart Haelterman, R&D Director at Recticel. “For the first time in history, polyurethane is truly fitting into a circular economy.” The European Union funded the PUReSmart project with €6M over a four-year period under its Horizon 2020 research and innovation programme (agreement No. 814543).

Building on the PUReSmart project, Covestro is working with partners from the waste management industry to drive the further development of flexible foam recycling through to industrial use. “Our goal is to turn waste into valuable raw materials and to anchor the principle of the circular economy in our company and along the value chain with our partners to achieve this,” says Christine Mendoza-Frohn, Head of Performance Materials Sales EMEA & LATAM of Covestro. ʺThat’s why we make innovative recycling a priority. We call this ongoing Evolution of Recycling: Evocycle^® CQ. The first initiative of this kind is dedicated to the chemolysis of PU mattress foam and is called ‘Evocycle^® CQ Mattress’. This underlines our willingness to further invest in this technology,” says Mendoza-Frohn.

Raw materials in high yield and purity

Unlike other chemical processes for recycling PU flexible foam, the process does not use fossil-based polyol. It requires only the pre-sorted foam from mattress waste, a glycol and an additive. During chemolysis, the polyol and toluene diamine (TDA), the precursor to TDI, are recovered in high purity and yield. After reprocessing, they can be used again as often as required for the production of new PU flexible foams. This ensures a sustainable circular economy for PU flexible foam with a reduced CO₂ footprint.

The goal: an industrial value cycle

Covestro’s first initiative, Evocycle^® CQ Mattress, transforms end-of-life mattress foam directly back into its main building blocks, giving old foam a new life within an optimised circular system. The company aims to close the loop in the PU mattress industry by converting waste into valuable resources, reducing the use of fossil fuels and significantly lowering CO₂ emissions. However, there are still many steps to be taken before this vision becomes reality, especially with regard to upscaling the process.

The journey began for Covestro in 2019, leading to the start of a pilot plant at its Leverkusen site as early as 2021 to verify the positive laboratory results achieved to date. If the trials continue to be successful, the company plans to build a larger recycling plant to validate the technology in an industrial simulation environment.

However, an effective and cost-efficient supply of used PU mattresses is also crucial to building a circular economy. To achieve this, large quantities must be collected, broken down into individual components such as springs, textiles and foam parts, and the foam components pre-sorted according to purity and density. This can only succeed in close cooperation with partners – in this case, in the recycling industry. Covestro is already cooperating on this with companies such as Interzero and Ecomaison (formerly Eco-mobilier).