POSSIBLE Project Finds Success in Mechanical Recycling of Rigid PU, GFRP
•February 16, 2026
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Why It Matters
Mechanical recycling integrates waste PU and GFRP into current production without costly new equipment, accelerating circularity in the thermoset market and delivering immediate cost and carbon savings.
Key Takeaways
- •Cannon demonstrates 3% recycled PU powder in foam
- •Up to 40% recycled granules integrated via Interwet-LFI
- •Process uses existing high‑pressure mixing heads, no new lines
- •Thermal conductivity rises only 4% with 3% recycled content
- •Screw conveyor handles granules up to 100 g/s flow
Pulse Analysis
The polyurethane and glass‑fiber‑reinforced polymer sectors have long struggled with end‑of‑life management because cross‑linked chemistries resist conventional mechanical recycling. Chemical depolymerisation routes exist, but they remain laboratory‑scale, costly, and often incompatible with high‑throughput manufacturing. In Europe, the EU recovery fund has earmarked resources for scalable, low‑impact solutions, prompting collaborations like the POSSIBLE project to explore alternatives that fit within existing plant footprints.
Cannon’s approach sidesteps the need for new reactors by leveraging its FPL 36 IW high‑pressure mixing head. In the first route, rigid foam is milled into fine (PU‑A) and coarse (PU‑B) powders, then blended into the polyol stream at up to 20 % of the polyol weight, creating a stable slurry even at viscosities above 10,000 mPa·s. Panels produced with 3 % recycled powder show only a 4 % increase in thermal conductivity, preserving insulation performance. The second route transforms waste PU and GFRP into granules that are fed directly into the Interwet‑LFI system via a flexible screw conveyor, achieving uniform filler distribution and enabling formulations with up to 40 % recycled content.
For manufacturers, the significance is twofold: environmental compliance and cost efficiency. By integrating recycled feedstock without redesigning production lines, firms can reduce raw‑material expenses and lower their carbon footprint, aligning with tightening EU sustainability mandates. The commercial rollout anticipated by Cannon could set a new industry standard for thermoset circularity, encouraging broader adoption of mechanical recycling across the polyurethane market and stimulating further investment in sustainable manufacturing technologies.
POSSIBLE project finds success in mechanical recycling of rigid PU, GFRP
The Cannon FPL 36 IW high-pressure mixing head dispenses polyurethane (PU) filled with rigid PU granules onto a mold. Source | The Cannon Group
The Cannon Group (Caronno Pertusella, Italy), in close cooperation with polyurethane (PU) processor MAP S.p.A. (Osio Sotto, Italy) and the University of Bergamo (Bergamo, Italy), presents its novel approach to recycling PU and glass fiber-reinforced PU composites recycling. Developed under the POSSIBLE (PrOduce SuStainabLE Industrial Bodies) project, co-funded by the Italian strategic plan for the EU recovery fund NextGenerationEU, Cannon has successfully demonstrated that ground foam and granulated parts can be used as secondary reinforcement materials in new composite formulations.
While valued for their mechanical and thermal resistance, stability and the possibility of incorporating reinforcing fibers, the combination of chemical cross-linking in the material and fibers makes traditional recycling of PU foams and glass fiber-reinforced polymers (GFRP) difficult. Scientific research has developed several potential chemical recycling routes, but these work on a laboratory scale and are often too slow, too expensive or incompatible with existing PU manufacturing processes.
In this context, the POSSIBLE project has emerged. Cannon’s process offers a more direct approach, reintegrating pure or composite rigid PU waste through two complementary methods, both compatible with its high-pressure systems.
“The underlying idea was not to disrupt the system’s chemistry, introduce complex process steps or require completely new lines,” explains Dario Pigliafreddo, mobility and specialties sales manager at Cannon, “but to apply to a well-known and well-performing application of glass fiber impregnation flexibility and modularity to add both recycled granulate and powder, adapting a high-pressure foaming platform that some PU manufacturers already use.”
During the project, two complementary approaches were explored. The first involved transforming rigid foam waste into micrometric powders, which were then dispersed into the polyol to form a slurry and dosed as a liquid component using a mixing head. The second involved using rigid PU granulate and glass fiber-reinforced PUs, introduced as a solid filler into the mixture using dedicated dosing systems combined with the FPL 36 IW mixing head for Interwet-LFI (long fiber injection) technology patented by Cannon.
Rigid foam waste → micrometric powders → polyol dispersion
For the first route, rigid foam waste is transformed into two types of powder: a fine powder (PU-A), with most particles below 75 micrometers, and a coarser powder (PU-B), between 300-500 micrometers. The dispersions were made by introducing the dried powders into a reactor with polyol, up to 20% by weight of the polyol stream, equal to about 5% of the foam.
To handle these dense slurries, Cannon divided the isocyanate and the polyol into two streams, one “clean” and one “loaded.” This way, the mixing energy remains high, and the system remains stable, even with viscosities that can exceed 10,000 mPa·s. Then, the slurry is dosed via a scraper cylinder.
Subsequent analyses show homogeneous panels with good distribution for the recycled powder. Furthermore, the thermal conductivity increases by only about 4% compared to the reference, which allows for maintaining valid insulating performance even with 3% recycled content in the foam.
Solid waste → granule transformation → solid filler dosing
For the second route, PU waste, including glass fiber-reinforced PU, is turned into granules. These are then dosed as a solid filler directly into the Interwet-LFI head. This technology is already in use to combine PU and shredded glass fiber, and allows recycled granules to be integrated into the mixing flow.
To determine the most efficient feeding system, both pneumatic fluid bed transport and a flexible screw conveyor were tested. The former offers good results with dense, regular granules, but becomes unstable with light or powdery materials. The flexible screw conveyor proved to be more versatile, enabling flow rates from a few grams to more than 100 grams/second, without pulsations or bridging, making it ideal for GFRP granules from waste. With this configuration, panels containing up to 40% recycled granules by weight were produced, with uniform distribution throughout the thickness.
Subsequent testing by Cannon showed that recycling rigid PU and GFRP can become an integral part of production lines. They do not require invasive processes or radical changes to formulations but transform waste into a material that can be reused in the process, with immediate economic and environmental benefits. This is a concrete step toward circularity in thermosets.
Based on research conducted during POSSIBLE, Cannon is now working on commercially viable solutions for recycling PU and GFRP that will enter the market in the near future.
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