MULTI-LAYER CORE GOLF BALL

• US 20150375061A1
• Filed: 09/13/2015
• Published: 12/31/2015
• Est. Priority Date: 08/05/2013
• Status: Active Grant

• Current Assignee: Acushnet Company (FILA Holdings Corp.)
• Original Assignee: Acushnet Company (FILA Holdings Corp.)
• Inventors: Sullivan, Michael J., Goguen, Douglas S., Comeau, Brian
• Granted Patent: US 9,586,097 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 37/0046 Deflection or compression
• CPC Class Codes: A63B 37/0061 Coefficient of restitution
• 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 37/0065 Deflection or compression
• 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 21/00 Compositions of unspecified rubbers
• CPC Class Codes: C08L 9/00 Compositions of homopolymers or copolymers of conjugated diene hydrocarbons

Abstract

Golf balls having a very high positive gradient multilayer core are provided. The multilayer core includes an outer core layer and a very soft, low compression inner core layer. The inner core layer is formed from an unfoamed composition and has a center hardness that is at least 40 Shore C points less than the outer surface hardness of the outer core layer.

Claims

1. A golf ball comprising a core and a cover, wherein the core consists of:

a solid inner core layer formed from an unfoamed first polybutadiene composition and having a diameter of 1.10 inch or less and a center Shore C hardness (H_center) of 40 or less,

one or more optional intermediate core layers, and

an outer core layer formed from a second polybutadiene composition and having a thickness of 0.150 inches or greater and an outer surface Shore C hardness (H_{outer surface}) of 80 or greater,

wherein H_{outer surface}>

H_center, and H_{outer surface}−

H_center≧

40, and

wherein the core has a gradient quotient, Q, of from 7 to 12, as defined by the equation;

2. The golf ball of claim 1, wherein the hardness gradient, G, is from 60 to 90.

3. The golf ball of claim 1, wherein the percent of trans-polybutadiene isomer at the surface of the outer core layer, T, is from 1 to 5.

4. The golf ball of claim 1, wherein the COR of the core is from 0.790 to 0.840.

5. The golf ball of claim 1, wherein H_{outer surface}−

H_center≧

45.

6. The golf ball of claim 1, wherein H_{outer surface}−

H_center≧

55.

7. The golf ball of claim 1, wherein H_{outer surface}−

H_center≧

60.

8. The golf ball of claim 1, wherein the inner core layer has a compression of <

0.

9. The golf ball of claim 8, wherein the core has an overall compression of ≧

70.

10. A golf ball comprising a core and a cover, wherein the core consists of:

a solid inner core layer formed from an unfoamed first polybutadiene composition and having a diameter of 1.10 inch or less and a center Shore C hardness (H_center) of 30 or less,

one or more optional intermediate core layers, and

an outer core layer formed from a second polybutadiene composition and having a thickness of 0.150 inches or greater and an outer surface Shore C hardness (H_{outer surface}) of 80 or greater,

wherein H_{outer surface}>

H_center, and H_{outer surface}−

H_center≧

50, and wherein the core has a gradient quotient, Q, of from 7 to 12, as defined by the equation;

11. The golf ball of claim 10, wherein the hardness gradient, G, is from 60 to 90.

12. The golf ball of claim 10, wherein the percent of trans-polybutadiene isomer at the surface of the outer core layer, T, is from 1 to 5.

13. The golf ball of claim 10, wherein the COR of the core is from 0.790 to 0.840.

14. The golf ball of claim 10, wherein H_{outer surface}−

H_center≧

55.

15. The golf ball of claim 10, wherein H_{outer surface}−

H_center≧

60.

16. The golf ball of claim 10, wherein H_{outer surface}−

H_center≧

65.

17. The golf ball of claim 10, wherein H_{outer surface}−

H_center≧

70.

18. The golf ball of claim 10, wherein the inner core layer has a compression of <

0.

19. The golf ball of claim 18, wherein the core has an overall compression of ≧

70.

20. The golf ball of claim 10, wherein the inner core layer composition is a thermoset composition consisting essentially of:

polybutadiene;

from 0.1 phr to 2.0 phr of a peroxide;

optionally 5 phr or less of a metal oxide;

optionally 5 phr or less of a metal coagent;

optionally 5 phr or less of a metal carbonate; and

optionally one or more additional components selected from the group consisting of fillers, colorants, and antioxidants.