Patent ID: 7214757

Claim:
A polyurethane elastomer comprising the reaction product of: a polyisocyanate prepolymer formed by reacting an isocyanate with a polyol, said polyisocyanate prepolymer being present in an amount of from 45 to 70 weight percent based on total weight of the elastomer composition; a polyether polyol prepolymer present in an amount of from 25 to 50 weight percent based on total weight of the elastomer composition; and a hardener mixture comprising at least one additional polyol and at least one charge-control agent, the at least one charge control agent being a polyol capable of being copolymerized with the polyisocyanate prepolymer, the polyether polyol, and the hardener mixture, the hardener m and n are integers which together are of sufficient value to achieve an R 1 weight average molecular weight of 300 to 30,000; p and q are integers which together are of sufficient value to achieve an R 7 weight average molecular weight of 300 to 30,000; and M represents hydrogen, an alkali metal, ammonium, or P + (C 6 H 5 ) 3 CH 3 .