Patent ID: 7964132

Claim:
A method of manufacturing golf balls having a core and at least one cover layer, the method comprising the steps of premixing a cover resin material comprising (A) a thermoplastic polyurethane, (B) a polyisocyanate compound and (C) a thermoplastic elastomer other than the thermoplastic polyurethane in a weight ratio (A):(B):(C)=100:{2-50}:{0-50} under an inert gas atmosphere in a mixing apparatus, cooling the cover resin material in an environment isolated from moisture and pelletizing it so as to form single pellets in an incompletely reacted state, charging the cover resin material in the form of the single resin pellets into a molding machine, and injecting the cover resin material in a molten state around a core at 150 to 250° C. so as to form a cover layer, wherein the cover resin material is injected with from 10 to 99% of the total number of isocyanate groups in component B remaining in an unreacted state within the cover resin material.