Open-pore flexible polyurethane (PUR) foam with varioius pore sizes (1-8 mm) was used as filler to reinforce low-density closed-cell PUR flexible foam. The final composite has a sandwich structure, where the core zone has “foam-in-foam” structure and skin zones are unreinforced PUR foams. Compared to the regular, non-sandwich one-layer PUR flexible foam, the structure composite exhibits improved mechanical properties: the support factor can be increased up to 65 percent and the compressive force deflection value can be increased almost 100 percent while the density of the composite increases only 25 percent.
