Golf ball

Patent metadata

Field	Value
Publication number	US-10695618-B2
Application number	US-201916383973-A
Country	US
Kind code	B2
Filing date	Apr 15, 2019
Priority date	Oct 20, 2015
Publication date	Jun 30, 2020
Grant date	Jun 30, 2020

Abstract

In order to satisfy at a high level the golf ball flight and control performances relied on by professional golfers and skilled amateurs, this invention provides a multi-piece solid golf ball G having a core 1, a cover 3 and an intermediate layer 2 therebetween wherein the core is formed of a rubber composition that includes a lower alcohol having a molecular weight below 200. Also, letting Hc be the JIS-C hardness at the center of the core, H12 be the JIS-C hardness at a position 12 mm from the core center and Ho be the JIS-C hardness at the surface of the core, the core has a hardness profile in which these hardnesses satisfy fixed relationships defined by specific formulas.

First claim

The invention claimed is:

1. A multi-piece solid golf ball comprising a core, a cover, and an intermediate layer situated therebetween and having a paint film layer formed on a surface of the cover, wherein the core is formed of a rubber composition containing the following ingredients (a) to (d):
(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; and,

letting Hc be the JIS-C hardness at a center of the core, H12 be the JIS-C hardness at a position 12 mm from the core center and Ho be the JIS-C hardness at a surface of the core, the core has a hardness profile which satisfies formulas (3) and (4) below
( Ho−H 12)−( H 12− Hc )≥0  (3)

22≤ Ho−Hc≤ 40  (4).

2. The golf ball of claim 1 , wherein the ball has a dynamic coefficient of friction which is 0.300 or more.

3. The golf ball of claim 1 , wherein the JIS-C hardness Hc at the core center is from 40 to 78 and the JIS-C hardness Ho at the core surface is from 65 to 99.

4. The golf ball of claim 1 wherein, letting H10 be the JIS-C hardness at a position 10 mm from the core center, the core hardness profile satisfies formula (1)′ below
0≤ H 10− Hc≤ 15  (1)′.

5. The golf ball of claim 1 wherein, letting H10 be the JIS-C hardness at a position 10 mm from the core center, the core hardness profile satisfies formula (2)′ below
15≤ Ho−H 10≤30  (2)′.

6. The golf ball of claim 1 wherein, letting H10 be the JIS-C hardness at a position 10 mm from the core center, the core hardness profile satisfies formula (3)′ below
( Ho−H 10)−( H 10− Hc )≥10  (3)′.

7. The golf ball of claim 6 wherein, letting (Ho−H10)−(H10−Hc) in formula (3)′ be A′, the spin index, defined as the dynamic coefficient of friction for the ball multiplied by A′, is 3.0 or more.

8. The golf ball of claim 6 wherein, letting (Ho−H10)−(H10−Hc) in formula (3)′ be A′, the hardness profile index, defined as the deflection (mm) of the core when compressed under a final load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf) multiplied by A′, is 30 or more.

9. The golf ball of claim 1 , wherein component (d) is included in an amount, per 100 parts by weight of the base rubber (a), of from 0.5 to 5 parts by weight.

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.

Assignees

• Bridgestone Sports Co Ltd

Inventors

• Kimura Akira
• Ogawana Toru
• Mochizuki Katsunobu
• Shindo Jun

Classifications

• A63B37/005 Primary

  Cores · CPC title

• A63B37/0076

  Multi-piece balls, i.e. having two or more intermediate layers · CPC title

• A63B37/0075

  Three piece balls, i.e. cover, intermediate layer and core · CPC title

• A63B37/0062 Primary

  Hardness · CPC title