Patent ID: 7223819

Claim:
A golf ball which 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 (ML1+4 (1000C)) no higher than 45.