abstract |
A golf ball 2 includes a core 4, a mid layer 6, a reinforcing layer 8, an inner cover 10, and an outer cover 12. The core 4 includes a center 18 and an envelope layer 20. The envelope layer 20 is formed by a rubber composition being crosslinked. The rubber composition includes a base rubber, a co-crosslinking agent, a crosslinking initiator, and an acid and/or a salt. The co-crosslinking agent is (1) an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms; and/or (2) a metal salt of an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms. A hardness Hc1 of the inner cover is greater than a hardness Hc2 of the outer cover. A thickness T1 of the inner cover is equal to or greater than 0.1 mm but equal to or less than 0.8 mm. |