Fraunhofer develops flexible PU foam with over 90% bio-based content
The OrganoFoam material is designed for conventional processing equipment and reportedly withstood 700 hours of accelerated UV ageing with little discoloration.
Researchers at the Fraunhofer Institute for Structural Durability and System Reliability LBF have developed a flexible polyurethane foam containing more than 90% bio-based material.
The patent-pending OrganoFoam formulation combines bio-based polyols and bio-based isocyanates with a small proportion of additives. According to the German institute, the predominantly open-cell foam provides the resilience required for mattresses, upholstered furniture and vehicle seating without needing natural fibres as a load-bearing structure.
The raw materials are normally used in coatings and are not inherently suited to flexible foam production. Fraunhofer LBF said it overcame this limitation by developing a formulation specifically tailored to the application.
Foam blocks weighing up to 8 kg were produced in the laboratory before being mechanically crushed to open their cellular structure and improve dimensional stability.
The materials were developed with German foam processor Friedrich Platt, which cut, bonded and upholstered the blocks using existing industrial equipment. A demonstration sofa was produced to assess comfort and durability under conditions representative of practical use.
Compression hardness and compression-set testing indicated that the fine-pored foam could compete with a conventional fossil-based reference material, Fraunhofer said.
The material also showed comparatively strong resistance to accelerated UV ageing. Conventional foam became yellow and brittle after 100 hours of exposure to UV lamps, while OrganoFoam showed little discoloration after 700 hours. Fraunhofer said suitable additives could provide further UV protection.
“Our project partner then cuts [the foam blocks] to form products such as seat and back cushions for sofas,” said Fraunhofer LBF researcher Roland Klein.
In addition to mattresses, furniture and automotive seating, potential applications include shock-absorbing packaging, acoustic insulation for walls and ceilings, and positioning aids used in medical care.
The OrganoFoam project was funded by the German Federal Ministry of Research, Technology and Space.
Photo: Fraunhofer LBF’s predominantly open-cell OrganoFoam contains more than 90% bio-based material and can be cut and processed using conventional industrial equipment. Caption: Fraunhofer LBF
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