Polyurethane is one of the most widely used plastics in modern life. It can be rigid, flexible or elastic, and its durability makes it suitable for products ranging from mattresses and furniture to insulation materials, automotive components and shoe soles.
Yet when these products reach the end of their service life, recycling polyurethane remains a major challenge.
A new chemical recycling technology developed at KU Leuven could provide a different route. The process developed by researchers at the university can break polyurethane waste down into its original chemical building blocks — polyols and isocyanates — which can then be used again to produce polyurethane.
The technology has now moved toward industrialization with the establishment of Purtiso, a KU Leuven spin-off founded to scale up the process and bring it to the market. Pilot testing with industrial partners is planned for 2027, followed by the development of a commercial demonstration plant.
Why Is Polyurethane Difficult to Recycle?
Polyurethane is found in a wide range of everyday and industrial products. According to KU Leuven, polyurethane accounts for an estimated 8% of plastics worldwide.
Its versatility comes from its chemical structure, but that same structure makes end-of-life recycling difficult. Most polyurethane products cannot simply be melted and reshaped like conventional thermoplastics such as polyethylene or polypropylene.
As a result, discarded polyurethane is often mechanically shredded or ground for lower-value applications, while some waste ends up in landfill. This means that much of the chemical value contained in the original material is lost.
There is also another challenge further upstream.
The two major building blocks used to make polyurethane — polyols and isocyanates — are still largely produced from fossil-based raw materials. Conventional isocyanate production also involves phosgenation, a process that uses highly toxic phosgene and requires strict safety controls.
Recovering these building blocks from existing polyurethane waste could therefore address two problems at the same time: waste management and dependence on virgin fossil-based feedstocks.
Recovering Both Polyols and Isocyanates
A research team led by Professor Dirk De Vos at KU Leuven's Faculty of Bioscience Engineering developed a chemical recycling process that breaks polyurethane back down into its original building blocks.
Former KU Leuven postdoctoral researcher Niels Van Velthoven developed the process and later founded Purtiso to commercialize the technology.
The key feature is the recovery of both polyols and isocyanates, rather than focusing on only one fraction of the polymer.
According to KU Leuven, the recovered compounds are of sufficiently high quality to be used again as building blocks for polyurethane production. Purtiso's patented PUR2ISO™ process similarly targets near-complete recovery of polyol and isocyanate building blocks for direct reuse in polyurethane manufacturing.
The basic concept is straightforward:
Polyurethane waste → chemical recycling → polyols + isocyanates → new polyurethane
This creates the foundation for a closed-loop approach in which an end-of-life PU product becomes a source of raw materials for new PU production.
A Chemical Recycling Route Without Phosgenation
One of the most notable aspects of the technology is its approach to isocyanate recovery.
Conventional industrial production of isocyanates commonly relies on phosgenation. Purtiso's process is designed to recover isocyanate building blocks from polyurethane waste without a phosgenation step. It also aims to reduce reliance on oil and gas as virgin feedstocks.
This gives the technology significance beyond conventional plastic recycling.
Instead of simply converting polyurethane waste into another material, the process attempts to recover the molecules needed to make polyurethane in the first place.
If this approach can be successfully implemented at industrial scale, recycled building blocks could partially replace virgin raw materials in polyurethane production and help keep existing carbon resources within the manufacturing cycle.
Designed for Multiple Polyurethane Waste Streams
Polyurethane waste is not a single, uniform material.
Flexible foam, rigid foam, polyisocyanurate (PIR) materials and elastomers can have very different chemical compositions and may contain additives or other components.
Purtiso says its PUR2ISO™ technology is optimized for flexible polyurethane foams, while it can also process major PU waste streams including flexible and rigid foams, PIR and certain elastomeric materials. The company also positions the process for mixed and relatively impure PU waste streams.
This feedstock flexibility could be important for commercial applications.
For example, used mattresses and furniture foam are considerably more complicated than clean production scrap. A recycling technology capable of handling such waste would have access to a much larger potential feedstock base.
From Laboratory Research to Pilot Testing
The technology was developed at KU Leuven with support from Flanders Innovation & Entrepreneurship (VLAIO) through an Innovation Mandate and the Moonshot programme, together with the university's Industrial Research Fund (IOF).
After several years of development, the technology has reached a stage where commercialization is becoming the next priority.
Purtiso was established as a KU Leuven spin-off to take the process beyond university research.
The company plans to work with industrial partners on pilot testing in 2027. Following the pilot phase, Purtiso intends to develop a commercial demonstration plant, with initial discussions already underway.
Purtiso's own technology information states that the process has been validated at bench scale (TRL 4–5) and is being prepared for pilot-scale implementation. The company says the quality of the recovered building blocks has been independently assessed by industry partners for reuse in polyurethane production.
The transition from laboratory validation to continuous pilot operation will be an important test of the technology. Industrial recycling processes need to deal with variations in feedstock, process stability, purification, operating costs and product consistency that are difficult to fully reproduce at laboratory scale.
A Modular Approach to Polyurethane Recycling
Purtiso's longer-term goal is not limited to a single large recycling facility.
The company aims to develop modular recycling plants capable of continuously converting polyurethane waste into polyols and isocyanates at industrial scale.
A modular model could have advantages for polyurethane waste because many PU products are bulky and relatively difficult to transport economically over long distances.
For example, waste foam from mattress or furniture manufacturing could potentially be processed closer to the source, with the recovered chemical building blocks subsequently returned to polyurethane production.
This creates a different model for the PU value chain:
PU waste → local chemical recycling → recovered building blocks → PU production → new products
The approach could potentially connect waste producers, chemical manufacturers and polyurethane processors within a more circular supply chain.
Why Isocyanate Recovery Matters
Chemical recycling of polyurethane has been studied for years, with many approaches focusing on the recovery of polyols.
Recovering the isocyanate side of the polymer chemistry is more challenging, which makes technologies capable of recovering both building blocks particularly relevant to the development of a more complete closed-loop system.
Purtiso's technology focuses on precisely this point: recovering both polyols and isocyanates from polyurethane waste and returning them to the production cycle.
This could also change how the industry thinks about polyurethane waste.
Instead of treating an old mattress, insulation panel or foam product primarily as a waste disposal problem, the material could potentially be viewed as a secondary source of chemical feedstock.
Potential Applications Across the PU Industry
The potential customer base for such a technology is broad because polyurethane is used across many industries.
Mattress manufacturers generate large volumes of flexible PU foam waste, including production scrap and end-of-life materials.
Insulation manufacturers use rigid polyurethane and PIR foams, creating another potential feedstock for chemical recycling.
Footwear manufacturers use polyurethane in soles and other components.
Furniture and automotive industries also generate significant quantities of flexible and semi-rigid polyurethane materials.
For polyurethane producers, recovered polyols and isocyanates could provide an additional source of circular raw materials and potentially reduce exposure to fluctuations in virgin petrochemical feedstocks.
From Waste Management to Circular Feedstock
The significance of the KU Leuven technology lies in the fact that it approaches polyurethane recycling from a chemical rather than purely mechanical perspective.
Mechanical recycling can extend the useful life of a material, but chemical recycling aims to go one step further by recovering the molecular building blocks themselves.
In the case of PUR2ISO™, the target is to return polyurethane waste to polyols and isocyanates that can re-enter the manufacturing process.
That distinction is important for a material as chemically complex and widely used as polyurethane.
The technology is still moving through the scale-up process, and pilot testing will be an important milestone before commercial deployment. Questions around feedstock preparation, continuous operation, economics and integration with existing PU manufacturing processes will need to be addressed at larger scale.
But the direction is clear: turning polyurethane waste back into the raw materials needed to make new polyurethane.
With Purtiso now working toward pilot testing and eventual commercial demonstration, the KU Leuven technology offers a potential new route for building a more circular polyurethane industry — one in which discarded PU products can become a source of high-value chemical feedstocks rather than simply a difficult waste stream.
