Golf ball
A golf ball for amateur golfers has both an excellent flight and a good, soft feel when hit by the average golfer whose head speed is not very high. The ball has a compressive deformation B when subjected to a final load of 50 kgf from an initial load of 5 kgf that is from 1.30 to 1.80 mm and a compressive deformation C when subjected to a final load of 90 kgf from an initial load of 5 kgf that is from 2.45 to 2.90 mm. The core of the ball has a hardness profile which satisfies the conditions (1) Cs−Cc≥20 and (2) Cs−Cs−3≤5.0, wherein Cs is the Shore C hardness at the core surface, Cs−3 is the Shore C hardness 3 mm inside the core and Cc is the Shore C hardness at the core center.
1. A golf ball comprising a core and a cover, wherein the ball has a compressive deformation B when subjected to a final load of 50 kgf from an initial load state of 5 kgf that is from 1.30 to 1.80 mm and a compressive deformation C when subjected to a final load of 90 kgf from an initial load state of 5 kgf that is from 2.45 to 2.90 mm, and the core has a hardness profile that satisfies the following conditions:
Cs−Cc≥ 20 (1)
Cs−Cs −3≤5.0, (2)
wherein Cs is the Shore C hardness at a surface of the core, Cs−3 is the Shore C hardness at a position 3 mm inside the core surface and Cc is the Shore C hardness at a center of the core, and
wherein the core is formed of a rubber composition comprising components (a) to (d) below:
(a) a base rubber,
(b) a co-crosslinking agent which is an α,β-unsaturated carboxylic acid or a metal salt thereof or both,
(c) a crosslinking initiator, and
(d) a lower alcohol having a molecular weight below 200.
2. The golf ball of claim 1 , wherein the compressive deformation A of the ball when subjected to a final load of 5 kgf from an initial load state of 0.2 kgf is 0.18 mm or less.
3. The golf ball of claim 1 , wherein the compressive deformation D of the ball when subjected to a final load of 130 kgf from an initial load state of 10 kgf is from 3.10 to 3.80 mm.
4. The golf ball of claim 1 , wherein the compressive deformation E of the ball when subjected to a final load of 30 kgf from an initial load state of 5 kgf is from 0.68 to 1.05 mm.
5. The golf ball of claim 3 , wherein the ratio D/A between compressive deformation D and compressive deformation A is at least 18.0.
6. The golf ball of claim 3 , wherein the ratio DB between compressive deformation D and compressive deformation B is from 2.02 to 2.40.
7. The golf ball of claim 3 , wherein the ratio D/C between compressive deformation D and compressive deformation C is from 1.20 to 1.31.
8. The golf ball of claim 4 , wherein the ratio D/E between compressive deformation D and compressive deformation E is from 3.50 to 4.10.
9. The golf ball of claim 1 , wherein component (d) is included in an amount of from 0.5 to 5 parts by weight per 100 parts by weight of the base rubber (a).
10. The golf ball of claim 1 , wherein component (d) is a monohydric, dihydric or trihydric alcohol.
11. The golf ball of claim 1 , wherein component (d) is butanol, glycerol, ethylene glycol or propylene glycol.
12. The golf ball of claim 1 , wherein the ball further comprises, between the core and the cover, at least an intermediate layer, which golf ball has a construction of three or more layers that includes the core, the intermediate layer and the cover.