Patent ID: 6723008
Filing Date: 2004-04-20
Classification: A63B

Abstract:
A multi-piece solid golf ball comprising a solid core and a cover of two inner and outer layers enclosing the solid core, whereinthe solid core has a deflection of at least 1.1 mm under an applied load of 294 N (30 kgf) and a surface and a center, the surface-center hardness difference given as a JIS-C hardness at the core surface minus a JIS-C hardness at the core center being up to 15 units, said cover inner layer is formed of a resin composition comprising as essential components, (a) 100 parts by weight of an olefin-unsaturated carboxylic acid random copolymer, an olefin-unsaturated carboxylic acid-unsaturated carboxylate random copolymer, a metal ion neutralized product of each said copolymer, or a mixture of each said copolymer and the neutralized product, (b) 5 to 80 parts by weight of a fatty acid having a molecular weight of at least 280 or derivative thereof, and (c) 0.1 to 10 parts by weight of a basic inorganic metal compound capable of neutralizing acid groups in components (a) and (b), said cover inner layer has a Shore D hardness of 45 to 65, said cover outer layer has a Shore D hardness of 35 to 55, said cover outer layer is softer than said cover inner layer, and the sum of dimple trajectory volumes each obtained by multiplying the volume of a dimple by the square root of a dimple diameter is 530 to 750.