Polyurethane golf club

Claim 1

A one-piece solid molded polyurethane vulcanizate golf club head having a unitary body including the entire front striking face and exhibiting the properties of a Shore D hardness in the range of about 50 to about 80, an elongation % at break of at least about 150 and not over about 350, a notched IZOD impact (ft. lb./in.) exceeding 4, a resiliency percentage exceeding 40, a recession characteristic exceeding about 0.55 mm, a recovery % between about 50-95, and an amortization % between about 4.5 and about 12; said polyurethane vulcanizate being a cured prepolymer, the prepolymer comprising the reaction product of (i) a diisocyanate selected from an aromatic diisocyanate, an isomer mixture of aromatic diisocyanates, a cycloaliphatic diisocyanate, and a mixture of an aromatic and cycloaliphatic diisocyanate, (ii) a polyalkylene ether glycol, and (iii) a low molecular weight (MW) glycol below about 350, the curing agent being an arylene primary diamine, the mole ratio of component (iii) to (ii) being in the range of about 0.25 to about 3.0, and the mole ratio of component (i) to (ii) plus (iii) being in the range of about 1.5 to 1.0::2.0 to 1.0, and the stoichiometric concentration of curing agent being sufficient to react with about 50 to 110% of the free isocyanato moieties in the prepolymer.