Patent ID: 7270612

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 and wherein the golf ball satisfies following conditions (1) to (8): (1) the core has a diameter of at least 36.7 mm 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 1.50 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; and (8) (deflection by core under 100 kg load)−(deflection by golf ball under 100 kg load)<1.0 mm, and 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 the intermediate layer is composed of (a) 100 parts by weight of an olefin-unsaturated carboxylic acid random copolymer and/or an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester random copolymer, (b) 5 to 80 parts by weight of a fatty acid having a molecular weight of at least 280 or a derivative thereof, and (c) 0.1 to 10 parts by weight of a basic inorganic metal compound capable of neutralizing acid groups on components (a) and (b).