Patent ID: 6786836
Filing Date: 2004-09-07
Classification: A63B

Abstract:
A golf ball comprising a solid core and a cover, said core being formed of a hot-molded product of a rubber composition comprising100 parts by weight of a base rubber composed of (a) 20 to 100 wt % of a polybutadiene having a cis-1,4 content of at least 60% and a 1,2 vinyl content of at most 2%, having a viscosity &eegr; at 25Â° C. as a 5 wt % solution in toluene of up to 600 mPaÂ·s, and satisfying the relationship: 10B+5&lE;A&lE;10B+60, wherein A is the Mooney viscosity (ML1+4 (100Â° C.)) of the polybutadiene and B is the ratio Mw/Mn between the weight-average molecular weight Mw and the number-average molecular weight Mn of the polybutadiene, in combination with (b) 0 to 80 wt % of a diene rubber other than component (a), (c) 10 to 60 parts by weight of an unsaturated carboxylic acid or a metal salt thereof or both, (d) 0.1 to 5 parts by weight of an organosulfur compound, (e) 5 to 80 parts by weight of an inorganic filler, and (f) 0.1 to 5 parts by weight of an organic peroxide; wherein the hot-molded product has a difference in JIS-C hardness between the center and surface thereof of more than 15 and up to 40 JIS-C hardness units and said solid core has a diameter of at least 37.0 mm.