Recent Developments in the Recycling of Flexible PU Foams Back into New PU Foam Products

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Two different approaches have been evaluated by The Dow Chemical Company to recycle flexible PU foams back into new flexible PU products: The first is the room-temperature pulverization process as developed and commercialized by Mobius Technologies California. The second is a solvolysis using dicarboxylic acid developed by Prof. Bauer of the Aalen University of Applied Sciences in Germany. For the recycling of slabstock PU foam production trim waste, only the pulverization process was used which provides a commercially attractive alternative to foam flocks rebonding. The process allows the recycling of trim foam back into new slabstock foam by introducing finely ground PU powder into the polyol and adjusting the recipes. New slabstock foam is produced with recycled foam loading of 10 to 15% by weight. Formulating approaches developed to closely match original foam performance – including the use of specifically tailored polyols, and liquid CO2 blowing – will be reviewed, as well as the influence of the PU powder filled foams. For molded PU foams used in car seats, both pulverization and solvolysis have been evaluated for recycling such foam back into automotive molded foams for car seats, head-rests, as well as noise & vibration insulation pads for use under car carpets. The recycled foams were used at concentrations of 5 to 10% by weight of the new molded foams. Foam performance met typical OEM’s specifications for such parts, and displayed good processability on existing PU foam molding equipment.