GOLF BALL

• US 20200129815A1
• Filed: 10/29/2019
• Published: 04/30/2020
• Est. Priority Date: 10/30/2018
• Status: Active Grant

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: Sumitomo Rubber Industries Limited
• Inventors: HAYASHI, Kai, SHIGA, Kazuyoshi, NAGAKURA, Hikaru, SHIGEMITSU, Takahiro
• Granted Patent: US 11,266,882 B2
• Time in Patent Office: Days
• CPC Class Codes: A63B 37/0039 characterised by the material
• CPC Class Codes: A63B 37/0043 Hardness
• CPC Class Codes: A63B 37/0045 Thickness
• CPC Class Codes: A63B 37/0051 Materials other than polybutadienes; Constructional details
• CPC Class Codes: A63B 37/00621 Centre hardness
• CPC Class Codes: A63B 37/00622 Surface hardness
• CPC Class Codes: A63B 37/0063 Hardness gradient
• CPC Class Codes: A63B 37/0064 Diameter
• CPC Class Codes: A63B 37/0075 Three piece balls, i.e. cover, intermediate layer and core
• CPC Class Codes: A63B 37/0076 Multi-piece balls, i.e. having two or more intermediate layers
• CPC Class Codes: A63B 37/0092 Hardness distribution amongst different ball layers
• CPC Class Codes: C08L 9/00 Compositions of homopolymers or copolymers of conjugated diene hydrocarbons

Abstract

An object of the present invention is to provide a golf ball having excellent durability. The present invention provides a golf ball comprising a spherical core composed of an inner core layer and an outer core layer, and at least one cover covering the spherical core, wherein the inner core layer is formed from an inner core layer rubber composition containing (a) a base rubber, (b) an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, (c) a crosslinking initiator, and (d) a terpene-based resin.

Claims

1. A golf ball comprising a spherical core composed of an inner core layer and an outer core layer, and at least one cover covering the spherical core, wherein the inner core layer is formed from an inner core layer rubber composition containing (a) a base rubber, (b) an α

,β

-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, (c) a crosslinking initiator, and (d) a terpene-based resin.

2. The golf ball according to claim 1, wherein (d) the terpene-based resin includes at least one member selected from the group consisting of a terpene polymer, a terpene-phenol copolymer, a terpene-styrene copolymer, a terpene-phenol-styrene copolymer, a hydrogenated terpene-phenol copolymer, a hydrogenated terpene-styrene copolymer, and a hydrogenated terpene-phenol-styrene copolymer.

3. The golf ball according to claim 1, wherein the terpene-based resin is at least one member selected from the group consisting of compounds having a structure represented by the following formulae (1) to (4):

4. The golf ball according to claim 1, wherein the inner core layer rubber composition contains (d) the terpene-based resin in an amount of from 3 parts by mass to 20 parts by mass with respect to 100 parts by mass of (a) the base rubber.

5. The golf ball according to claim 1, wherein (d) the terpene-based resin has a softening point in a range of from 60°

C. to 150°

C.

6. The golf ball according to claim 1, wherein a blending ratio (component (b)/component (d)) of the component (b) to the component (d) ranges from 2.0 to 15.0 in a mass ratio.

7. The golf ball according to claim 1, wherein the base rubber contains a high-cis polybutadiene having a cis-1,4 bond in a proportion of 90 mass % or more.

8. The golf ball according to claim 1, wherein a hardness difference (Hs1−

Ho) between a center hardness (Ho) of the inner core layer and a surface hardness (Hs1) of the inner core layer is 10 or less in Shore C hardness.

9. The golf ball according to claim 1, wherein the outer core layer is formed from a rubber composition.

10. The golf ball according to claim 9, wherein the rubber composition for the outer core layer contains (a) a base rubber, (b) an α

,β

-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, and (c) a crosslinking initiator.

11. The golf ball according to claim 10, wherein the rubber composition for the outer core layer does not contain a terpene-based resin.

12. The golf ball according to claim 1, wherein a center hardness (Ho) of the inner core layer ranges from 40 to 90 in Shore C hardness.

13. The golf ball according to claim 1, wherein a surface hardness (Hs1) of the inner core layer ranges from 40 to 90 in Shore C hardness.

14. The golf ball according to claim 1, wherein a diameter of the inner core layer ranges from 5 mm to 35 mm.

15. The golf ball according to claim 1, wherein a thickness of the outer core layer ranges from 2.5 mm to 17.5 mm.

16. The golf ball according to claim 1, wherein a surface hardness (Hs2) of the outer core layer ranges from 50 to 100 in Shore C hardness.

17. The golf ball according to claim 1, wherein a hardness difference (Hs2−

Ho) between a surface hardness (Hs2) and a center hardness (Ho) of the spherical core ranges from −

20 to 20 in Shore C hardness.