Patent ID: 7488779
Filing Date: 2009-02-10
Classification: A63B,C08K,C08L

Abstract:
1. A golf ball comprising a solid core, an intermediate layer and a cover layer wherein the solid core is formed from a vulcanized rubber compound composed of, 100 parts by weight of a rubber base material, 10 to 60 parts by weight of an unsaturated carboxylic acid and/or a metal salt thereof, 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 3 parts by weight of an organic peroxide, said rubber base material being composed of a first polybutadiene accounting for 80 to 95 wt % and a second polybutadiene accounting for 5 to 20 wt %, both polybutadiene being synthesized by using a rare earth element-based catalyst, said first polybutadiene containing no less than 60 wt % of cis-1,4 bonds and having a Mooney viscosity (ML 1+4 (100° C.)) no lower than 50 and said second polybutadiene containing no less than 60 wt % of cis-1,4 bonds and having a Mooney viscosity (ML 1+4 (100° C.)) no higher than 45, the solid core has a deflection under a load of 980 N (100 kg) of no less than 2.0 mm and no more than 6.0 mm, the intermediate layer has a thickness no smaller than 0.5 mm and no larger than 3.0 mm, and the cover has a thickness of no smaller than 0.7 mm and no larger than 3.0 mm.