abstract |
A golf ball 2 includes a core 4, a mid layer 6, and a cover 10. The core 4 includes a center 16, a first envelope layer 18, and a second envelope layer 20. The first envelope layer 18 is formed by a first rubber composition being crosslinked. The second envelope layer 20 is formed by a second rubber composition being crosslinked. The first rubber composition and/or the second rubber composition include: 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. |