Patent ID: 7387581

Claim:
A solid golf ball comprising a solid core, a cover layer that encloses the core, and a plurality of dimples formed on an outside surface of an outermost layer of the cover, the solid golf ball being characterized in that the solid core is formed of a rubber composition composed of 100 parts by weight of a base rubber that includes 60 to 100 parts by weight of a polybutadiene rubber having a cis-1,4 bond content of at least 60% and synthesized using a rare-earth catalyst, 0.1 to 5 parts by weight of an organosulfur compound, and an unsaturated carboxylic acid or a metal salt thereof, an organic peroxide and an inorganic filler; the solid core has a deformation, when subjected to loading from an initial load of 10 kgf to a final load of 130 kg, of 2.0 to 3.5 mm, and has the hardness distribution shown in the table below; the cover layer is formed by injection-molding a single resin composition of primarily (A) a thermoplastic polyurethane and (B) a polyisocyanate compound, and at least some polyisocyanate compound in which all the isocyanate groups on the molecule remain in an unreacted state is present in the resin composition, and has a thickness of 0.5 to 2.5 mm, a Shore D hardness at the surface of 50 to 70 and the surface hardness of the core is from 1 to 15 Shore D hardness units lower than the surface hardness of the cover; and the golf ball has a deformation, when subjected to loading from an initial load of 10 kgf to a final load of 130 kgf, of 2.0 to 2.9 mm. Hardness Distribution in Solid Core Shore D hardness Center 35 to 55 Region located 5 to 10 mm from center 39 to 58 Region located 15 mm from center 48 to 66 Surface 50 to 68 Hardness difference between center and surface 5 to 20