US Patent 8247466 Variable felted polyurethane foams for sponges and wipes

A polyurethane foam sponge that picks up at least 80% of water in a wipe dry performance test is made by variably felting (compressing under heat and pressure) a foam sheet to a compression ratio of about 1.05 to 2.9. The resulting foam sponge has from 5% to 25% of its top and bottom surface portions modified by the variable felting, while its core portion remains substantially unmodified.