Patent ID: 9205309
Filing Date: 2015-12-08
Classification: A63B,C08K

Abstract:
1. A golf ball comprising a spherical core, a mid layer positioned outside the core, and a cover positioned outside the mid layer, wherein the core is formed from a crosslinked rubber composition that includes: (a) base rubber; (b) a co-crosslinking agent; (c) a crosslinking initiator; and (d) a carboxylate having a carboxylic acid component that includes 4 to 8 carbon atoms, wherein the co-crosslinking agent (b) is: (b1) an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms; and/or (b2) a metal salt of an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms, the carboxylate (d) is present in an amount that is equal to or greater than 1.0 parts by weight but equal to or less than 10 parts by weight per 100 parts by weight of the base rubber (a), the carboxylate carboxylic acid component excludes the α, β-unsaturated carboxylic acid the mid layer has a Shore D hardness Hm that is greater than the cover Shore D hardness Hc, the core has a hardness distribution such that if JIS-C hardness values are measured at nine points in the core at intervals of 12.5% of the radius of the core including the core center and core surface, and the hardness values are plotted versus distance in a graph, then R a JIS-C hardness H(0) at a central point of the core is equal to or greater than 40 but equal to or less than 70, a JIS-C hardness H(100) at a surface of the core is equal to or greater than 78 but equal to or less than 96, and a difference (H(100)−H(0)) between the hardness H(100) of the core surface and the hardness H(0) of the core central point is equal to or greater than 15.