Recent Technical Advances in Recycling of Scrap Polyurethane Foam as Finely Ground Powder in Flexible Foam

Although the feasibility of using finely ground foam as filler in new foam has been previously demonstrated, the economics of the process have been poor because of high grinding costs. Recently commercialized advances in non-cryogenic grinding technology have provided a cost-effective method for producing fine powders from scrap polyurethane foam. Powder with a maximum particle size of 125 μm can now be obtained at low cost from production trim scrap, fabrication scrap, and changeover blocks. Details of the new grinding process and subsequent mixing and handling of powder/polyol slurries are presented. We present the results of commercial-scale trials of slab-stock and molded flexible polyurethane foams using finely ground polyurethane foam at levels up to 10% by weight in the foam. The formulations were adjusted to maintain foam density and hardness. The other physical properties and processing conditions compared well to standard, unfilled formulations. Formulation adjustments were minor—the most significant change is a slight increase in water and a corresponding change for isocyanate to maintain foam density.