Patent ID: 7250010

Claim:
A golf ball, comprising a material molded under heat from a rubber composition comprised of (a) a diene base rubber, (b) an α,β-unsaturated carboxylic acid and/or a metal salt thereof, and (c) an organic peroxide, wherein the organic peroxide (c) includes an aliphatic peroxyester, wherein the diene base rubber (a) includes a polybutadiene having a stress relaxation time (T 80 ), defined as the length of time from the moment when rotor rotation is stopped immediately after measurement of the ML 1+4 (100° C.) value (the Mooney viscosity measured at 100° C. in accordance with ASTM D-1646-96) that is required for the ML 1+4 value to decrease 80%, of at most 4 seconds, and wherein the polybutadiene having a stress relaxation time (T 80 ) of at most 4 seconds is a polybutadiene prepared by polymerization using a rare-earth catalyst.