Patent ID: 7601290

Claim:
A method of manufacturing golf balls composed of a core and a cover of one or more layer that encloses the core, at least one cover layer being made of a thermoplastic polyurethane composition characterized by including at least 90 wt % of a thermoplastic polyurethane obtained by a polyurethane-forming reaction of an organic diisocyanate compound with a long-chain polyol and a chain extender, which thermoplastic polyurethane composition cover layer has an inherent viscosity in a DMF solvent of larger than 1.5 dl/g and an inherent viscosity in a 0.05 mol/L n-butylamine containing DMF solution of larger than 0.5 dl/g, the golf ball manufacturing method being characterized by: conditioning the thermoplastic polyurethane, to a pre-processing moisture content of 500 ppm or less, then injection molding the moisture-conditioned thermoplastic polyurethane to form the thermoplastic polyurethane composition cover layer.