CPC A63B 37/00921 (2020.08) [A63B 37/0032 (2013.01); A63B 37/0033 (2013.01); A63B 37/0039 (2013.01); A63B 37/0045 (2013.01); A63B 37/0063 (2013.01); A63B 37/0075 (2013.01)] | 18 Claims |
1. A golf ball, comprising:
a solid core having an outer surface and a geometric center, wherein the solid core is formed from a rubber composition cured under heat, the rubber composition comprising:
a base rubber consisting of polybutadiene rubber,
an organic peroxide,
a cross-linking co-agent comprising a zinc salt of an acrylate, diacrylate, methacrylate, or dimethacrylate,
calcium sulfate dihydrate present in the rubber composition in an amount of about 1 phr to about 3.9 phr,
wherein the geometric center and the outer surface each has a hardness and the hardness of the geometric center ranges from about 45 Shore C to about 65 Shore C and the hardness of the outer surface ranges from about 80 Shore C to about 100 Shore C, and
wherein the hardness of the outer surface is greater than the hardness of the geometric center to define a positive hardness gradient of at least 30 Shore C units; and
a cover layer surrounding the solid core, wherein the cover layer comprises an ionomer, polyurethanes, polyureas, polyurethane-urea hybrids, or copolymers and blends thereof.
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