Multi-layer core golf ball

• US 7,993,218 B2
• Filed: 05/03/2010
• Issued: 08/09/2011
• Est. Priority Date: 01/10/2008
• Status: Active Grant

• Current Assignee: Acushnet Company (FILA Holdings Corp.)
• Original Assignee: Acushnet Company (FILA Holdings Corp.)
• Inventors: Sullivan, Michael J., Goguen, Douglas S., Ladd, Derek A., Comeau, Brian
• Primary Examiner(s): Trimiew; Raeann
• Application Number:
  US12/772,478
• Publication Number:
  US 20100216573A1
• Time in Patent Office: 463 Days
• Field of Search: 473/376, 473/373, 473/374
• US Class Current: 473/376
• CPC Class Codes: A63B 37/0003 Golf balls
• CPC Class Codes: A63B 37/0031 Hardness
• CPC Class Codes: A63B 37/0033 Thickness
• CPC Class Codes: A63B 37/0035 Density; Specific gravity
• CPC Class Codes: A63B 37/0045 Thickness
• CPC Class Codes: A63B 37/0047 Density; Specific gravity
• CPC Class Codes: A63B 37/00621 Centre hardness
• CPC Class Codes: A63B 37/00622 Surface hardness
• CPC Class Codes: A63B 37/0064 Diameter
• CPC Class Codes: A63B 37/0066 Density; Specific gravity
• CPC Class Codes: A63B 37/0076 Multi-piece balls, i.e. having two or more intermediate layers

Abstract

Golf balls consisting of a multi-layer core and a cover are disclosed. The multi-layer core comprises a thermoset rubber center, a thermoplastic intermediate core layer, and a thermoset rubber outer core layer.

Claims

1. A golf ball comprising:

a center formed from a first thermoset rubber composition and having a diameter of from 1.250 inches to 1.580 inches, a center hardness of from 40 Shore C to 90 Shore C, and a surface hardness of from 50 Shore C to 95 Shore C;

an intermediate core layer formed from a thermoplastic composition and having a thickness of 0.005 inches to 0.100 inches and a surface hardness of 60 Shore D or less;

an outer core layer formed from a second thermoset rubber composition and having a thickness of 0.010 inches to 0.100 inches and a surface hardness of 45 Shore C or greater; and

a cover layer having a thickness of from 0.010 inches to 0.050 inches and a surface hardness of 60 Shore D or greater;

wherein each of the core layers has a specific gravity of 1.25 g/cc or less.

2. The golf ball of claim 1, wherein the center has a negative hardness gradient.

3. The golf ball of claim 1, wherein the center has a zero hardness gradient.

4. The golf ball of claim 1, wherein the center has a positive hardness gradient wherein the difference between the center hardness and the surface hardness of the center is 45 or less.

5. The golf ball of claim 1, wherein the center has a diameter of from 1.350 inches to 1.490 inches.

6. The golf ball of claim 5, wherein the intermediate core layer has a thickness of from 0.040 inches to 0.090 inches.

7. The golf ball of claim 5, wherein the intermediate core layer has a thickness of from 0.020 inches to 0.050 inches.

8. The golf ball of claim 1, wherein the surface hardness of the intermediate core layer is from 35 Shore D to 55 Shore D.

9. The golf ball of claim 1, wherein the center has a compression of 80 or less.

10. The golf ball of claim 1, wherein the outer core layer has a thickness of from 0.030 inches to 0.080 inches.

11. The golf ball of claim 1, wherein the outer core layer has a thickness of from 0.030 inches to 0.040 inches.

12. The golf ball of claim 1, wherein the surface hardness of the outer core layer is from 70 Shore C to 95 Shore C.

13. The golf ball of claim 1, wherein the surface hardness of the outer core layer is greater than the surface hardness of the center.

14. The golf ball of claim 1, wherein the surface hardness of the outer core layer is less than the surface hardness of the center.

15. The golf ball of claim 1, wherein the surface hardness of the intermediate core layer is greater than the surface hardness of both the center and the outer core layer.

16. The golf ball of claim 1, wherein the first and second thermoset rubber compositions are the same or different diene rubber-based compositions.

17. The golf ball of claim 1, wherein the second thermoset rubber composition comprises from 1 phr to 100 phr of a stiffening agent.

18. The golf ball of claim 1, wherein the thermoplastic composition of the intermediate core layer is selected from the group consisting of partially- and fully-neutralized ionomers optionally blended with a maleic anhydride-grafted non-ionomeric polymer;

polyester elastomers;

polyamide elastomers; and

combinations of two or more thereof.

19. A golf ball comprising:

a center formed from a first diene rubber composition and having a diameter of from 1.250 inches to 1.580 inches, a center hardness of from 40 Shore C to 90 Shore C, and a surface hardness of from 70 Shore C to 95 Shore C;

an intermediate core layer formed from a thermoplastic composition and having a thickness of 0.005 inches to 0.100 inches and a surface hardness of 60 Shore D or less;

an outer core layer formed from a second diene rubber composition and having a thickness of 0.010 inches to 0.100 inches and a surface hardness of from 70 Shore C to 95 Shore C; and

a cover layer having a thickness of from 0.010 inches to 0.050 inches and a surface hardness of 60 Shore D or greater;

wherein each of the core layers has a specific gravity of 1.25 g/cc or less.

20. A golf ball consisting essentially of:

a center formed from a first diene rubber composition and having a diameter of from 1.350 inches to 1.490 inches, a center hardness of from 40 Shore C to 90 Shore C, and a surface hardness of from 70 Shore C to 90 Shore C;

an intermediate core layer formed from a thermoplastic composition and having a thickness of 0.005 inches to 0.100 inches and a surface hardness of 60 Shore D or less;

an outer core layer formed from a second diene rubber composition and having a thickness of 0.010 inches to 0.100 inches and a surface hardness of from 70 Shore C to 90 Shore C; and

a cover layer having a thickness of from 0.010 inches to 0.050 inches and a surface hardness of 60 Shore D or greater;

wherein each of the core layers has a specific gravity of 1.25 g/cc or less.

21. The golf ball of claim 20, wherein the intermediate core layer is formed from an ionomer composition.

22. The golf ball of claim 20, wherein the intermediate core layer is formed from a polyester elastomer composition.

23. The golf ball of claim 20, wherein the intermediate core layer is formed from a polyamide elastomer composition.

24. The golf ball of claim 20, wherein the cover layer is formed from an ionomer composition.