Patent ID: 7066836

Claim:
A golf ball, comprising a core, an intermediate layer enclosing the core and a cover enclosing the intermediate layer, wherein the intermediate layer and cover are each made from an ionomer resin-containing thermoplastic resin, wherein the golf ball satisfies following conditions (1) to (9): (1) the core has a diameter of at least 36.7mm but not more than 40.7 mm; (2) the core has a deflection when subjected to a load of 100 kg of at least 3.5 but not more than 6.0 mm; (3) the intermediate layer has a thickness of at least 0.50 mm but not more than 1.40 mm; (4) the intermediate layer has a Shore D hardness of at least 40 but not more than 55; (5) the cover has a thickness of at least 0.50 mm but not more than 1.40 mm; (6) the cover has a Shore D hardness of at least 60 but not more than 70; (7) the golf ball has a deflection when subjected to a load of 100 kg of at least 2.8 mm but not more than 4.5 mm; (8) (deflection by core under 100 kg load)−(deflection by golf ball under 100 kg load)<1.0 mm; and (9) (Shore D hardness of cover)−(Shore D hardness of intermediate layer)≧10; wherein the core is obtained by molding and vulcanizing a rubber composition comprising 100 parts by weight of a base rubber which includes 60 to 100 wt % of a polybutadiene of at least 60% cis-1,4 structure, has a Mooney viscosity (ML 1+4 (100° C.)) of at least 40 and is synthesized using a rare earth catalyst, 10 to 60 parts by weight of an unsaturated carboxylic acid and/or an unsaturated carboxylic acid metal salt, 0.1 to 5 parts by weight of an organosulfur compound, 5 to 80 parts by weight of an inorganic filler, and 0.1 to 0.8 part by weight overall of at least two different organic peroxides which have a half-life ratio q t /p t of at least 7 but not more than 20, wherein the organic peroxide with the shortest half-life at 155° C. is (p), the organic peroxide with the longest half-life at 155° C. is (q), the half-life of (p) is p t and the half-life of (q) is q t ; the intermediate layer is made from a thermoplastic resin containing at least 30 wt % of an ionomer resin; and the cover is made from a thermoplastic resin containing at least 50 wt % of an ionomer resin.