The composition comprised of the polyurethane precursor (i.e., the polyisocyanate compound and the polyol or the polyisocyanate prepolymer and the polyol), the mineral oil, the coupling agent, and, optionally, the catalyst and other additives, has an initial viscosity, at from about 15??? C. to about 50??? C., within the range of from about 10 to about 100 centipoise.