Rubber composition for golf ball, and golf ball

Patent metadata

Field	Value
Publication number	US-11458369-B2
Application number	US-202016914721-A
Country	US
Kind code	B2
Filing date	Jun 29, 2020
Priority date	Jun 11, 2018
Publication date	Oct 4, 2022
Grant date	Oct 4, 2022

Abstract

A rubber composition for golf balls includes (a) a base rubber, (b) a co-crosslinking agent which is an α,β-unsaturated carboxylic acid and/or a metal salt thereof, (c) a crosslinking initiator, and (d) an alcohol having a value obtained by dividing the molecular weight of the alcohol by the number of hydroxyl groups thereon which is 70 or less. When the rubber composition is used in a golf ball having a core and a cover of one or more layers encasing the core, by setting the hardness difference in the core interior hardness profile to a large value while maintaining a desired core hardness, low spin properties can be manifested on golf ball shots, enabling the flight performance of the ball to be improved.

First claim

The invention claimed is:

1. A rubber composition for golf balls, comprising:
(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) an alcohol having a value obtained by dividing the molecular weight of the alcohol by the number of hydroxyl groups thereon which is 70 or less,
wherein the amount of component (d) is from 0.1 to 10 parts by weight per 100 parts by weight of the base rubber (a) wherein (d) is a hexahydric or lower alcohol.

2. The rubber composition of claim 1 , wherein the amount of component (d) is from 0.5 to 5 parts by weight per 100 parts by weight of the base rubber (a).

3. The rubber composition of claim 1 , wherein component (d) is selected from the group consisting of glycerol, ethylene glycol, propylene glycol, butanetriol, trimethylolethane, trimethylolpropane, di(trimethylolpropane), pentaerythritol and sorbitol.

4. The rubber composition of claim 1 , further comprising (e) an organosulfur compound.

5. The rubber composition of claim 1 wherein the vulcanized form of the rubber composition is a golf ball core.

6. The rubber composition of claim 5 , wherein the vulcanized rubber composition has a surface and a center with a hardness difference therebetween of at least 20 on the JIS-C hardness scale.

7. A golf ball comprising a core and a cover of one or more layers encasing the core, wherein the core is formed of the rubber composition of claim 1 .

8. The golf ball of claim 7 , wherein the core has a hardness profile in which a surface and a center of the core have a hardness difference therebetween of at least 20 on the JIS-C hardness scale.

Assignees

• Bridgestone Sports Co Ltd

Inventors

• Shindo Jun

Classifications

• C08L9/00

  Compositions of homopolymers or copolymers of conjugated diene hydrocarbons · CPC title

• C08K3/36

  Silica · CPC title

• A63B37/0038

  Intermediate layers, e.g. inner cover, outer core, mantle · CPC title

• C08K5/09

  Carboxylic acids; Metal salts thereof; Anhydrides thereof · CPC title

• C08K5/36

  Sulfur-, selenium-, or tellurium-containing compounds {(C08K5/0091 takes precedence)} · CPC title