Abstract: Energy absorbing polyurethane elastomer compositions having a density of from about 0.4 to about 1 gm/cc, a compression set of less than about 5% and a recovery time of from about 10 to about 100 milliseconds containing a light-weight filler are formed by reaction of a urethane-forming component comprising a compound containing at least four urethane-forming reactive sites and capable of forming stable complexes through unsatisfied urethane-forming reactive sites, an elasticizing polyol selected from the group consisting of diols and triols, and a diisocyanate in less than stoichiometric amounts.

Abstract: A novel elastomer having a very low compression set and a very slow recovery from compression comprises a flexible polyurethane of essentially linear structure containing unsatisfied hydroxyl groups, and is the reaction product of substantially linear polyols having hydroxyl end groups and an average molecular weight in the range 600 to 1200, with an aromatic isocyanate in less than stoichiometric amount. This elastomer can be used as one layer of an energy-absorbing material, in combination with a more difficultly compressible layer comprising a tough flexible polymeric matrix having a plurality of rigid hollow bodies embedded therein.