US Patent 7183357 Golf ball

A golf ball has a core obtained by molding and vulcanizing a rubber composition comprising (A) a base rubber which includes a polybutadiene having a cis-1,4 content of at least 60 wt %, (B) an unsaturated carboxylic acid and/or metal salt thereof, (C) an inorganic filler and (D) at least one organic peroxide selected from among 1,1-bis(t-hexylperoxy)cyclohexane, 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane, and 2,2-bis(4,4-di-t-butylperoxycyclohexyl)propane. The golf ball has excellent rebound characteristics and flight performance as well as a high productivity due to a reduced vulcanization time.