Multi-layer core golf ball

• US 8,870,684 B2
• Filed: 08/30/2011
• Issued: 10/28/2014
• 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., Ladd, Derek A.
• Primary Examiner(s): Gorden, Raeann
• Application Number:
  US13/221,886
• Publication Number:
  US 20110312445A1
• Time in Patent Office: 1,155 Days
• Field of Search: 473/376
• US Class Current: 473/376
• CPC Class Codes: A63B 37/0027 Polyurea
• CPC Class Codes: A63B 37/0031 Hardness
• CPC Class Codes: A63B 37/0033 Thickness
• CPC Class Codes: A63B 37/0043 Hardness
• 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 37/0063 Hardness gradient
• 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
• CPC Class Codes: A63B 37/0092 Hardness distribution amongst different ball layers

Abstract

Golf balls comprising a multi-layer core and a cover are disclosed. The multi-layer core comprises a zero or positive hardness gradient center that is hard relative to an intermediate core layer. The overall core preferably has a zero hardness gradient, a negative hardness gradient, or a positive hardness gradient of up to 20 Shore C units.

Claims

1. A golf ball comprising a core and a cover, wherein the core has an overall diameter of from 1.40 inches to 1.62 inches and comprises:

a center having a diameter of from 0.100 inches to 0.950 inches, a center Shore C hardness (H_center) of 90 or less, an outer surface Shore C hardness (H_{center surface}) of 75 or greater, wherein H_{center surface}>

H_center;

an intermediate core layer having an outer surface Shore C hardness (H_intermediate) of 85 or less; and

an outer core layer having an outer surface Shore C hardness (H_{outer core}) of 80 or greater;

wherein H_intermediate<

H_{center surface}, H_intermediate<

H_{outer core}, and H_{outer core}−

H_center≦

20.

2. The golf ball of claim 1, wherein H_{outer core}−

H_center≧

15.

3. The golf ball of claim 1, wherein H_{outer core}−

H_center≧

10.

4. The golf ball of claim 1, wherein H_{outer core}−

H_center≧

0.

5. The golf ball of claim 1, wherein the specific gravity of the outer core layer is within 0.01 g/cc of the specific gravity of the intermediate core layer.

6. The golf ball of claim 1, wherein the center is formed from a rubber composition.

7. The golf ball of claim 1, wherein the overall diameter of the core is from 1.500 inches to 1.580 inches.

8. The golf ball of claim 1, wherein the diameter of the center is from 0.125 inches to 0.750 inches.

9. The golf ball of claim 1, wherein the diameter of the center is from 0.250 inches to 0.675 inches.

10. The golf ball of claim 1, wherein the intermediate core layer and the outer core layer each have a specific gravity of from 1.13 g/cc to 1.18 g/cc.

11. The golf ball of claim 1, wherein the intermediate core layer and the outer core layer each have a specific gravity of from 1.09 g/cc to 1.19 g/cc.

12. The golf ball of claim 1, wherein H_{center surface} is from 75 to 89 and H_center is less than 89.

13. The golf ball of claim 12, wherein H_{outer core} is 85 or greater.

14. The golf ball of claim 12, wherein H_{outer core} is 89 or greater.

15. The golf ball of claim 1, wherein H_intermediate is 80 or less.

16. The golf ball of claim 1, wherein a subassembly consisting of the center and the intermediate core layer has a compression of 55 or less.

17. The golf ball of claim 16, wherein the golf ball has an overall compression of from 60 to 100.

18. The golf ball of claim 1, wherein the cover consists of:

an inner cover layer having an outer surface hardness of 65 Shore D or greater and a thickness of from 0.020 inches to 0.080 inches, and

an outer cover layer having an outer surface hardness of 60 Shore D or less and a thickness of from 0.015 inches to 0.055 inches.

19. The golf ball of claim 1, wherein the cover consists of:

an inner cover layer formed from a partially or fully neutralized ionomer composition and having an outer surface hardness of 65 Shore D or greater and a thickness of from 0.030 inches to 0.040 inches, and

an outer cover layer formed from a polyurethane or polyurea composition and having an outer surface hardness of 50 Shore D or less and a thickness of from 0.025 inches to 0.035 inches.