MULTI-LAYER CORE GOLF BALL

• US 20110237352A1
• Filed: 06/06/2011
• Published: 09/29/2011
• 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
• Granted Patent: US 8,221,268 B2
• Time in Patent Office: Days
• 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 37/0043 Hardness
• CPC Class Codes: A63B 37/0044 Hardness gradient
• 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 37/0076 Multi-piece balls, i.e. having two or more intermediate layers
• CPC Class Codes: A63B 37/0087 Deflection or compression
• CPC Class Codes: A63B 37/12 Special coverings , i.e. outer layer material balls with finger holes A63B37/0001, golf ball covers A63B37/0023

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 greater than 60 Shore D;

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 50 Shore C or greater;

an inner cover layer having a surface hardness of from 50 Shore D to 65 Shore D; and

an outer cover layer having a surface hardness of from 40 Shore D to 60 Shore D;

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 positive hardness gradient wherein the difference between the center hardness and the surface hardness of the center is from 10 to 45.

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

4. The golf ball of claim 1, wherein the outer core layer has a surface hardness of 80 Shore C or greater.

5. The golf ball of claim 4, wherein the surface hardness of the outer core layer is greater than the surface hardness of the center.

6. The golf ball of claim 1, wherein the outer core layer has a surface hardness of from 50 Shore C to 80 Shore C.

7. The golf ball of claim 6, wherein the surface hardness of the outer core layer is less than the surface hardness of the center.

8. The golf ball of claim 1, wherein the center has a diameter of from 1.400 inches to 1.500 inches.

9. The golf ball of claim 8, wherein the intermediate core layer has a thickness of from 0.040 inches to 0.060 inches.

10. The golf ball of claim 9, wherein the outer core layer has a thickness of from 0.030 inches to 0.040 inches.

11. The golf ball of claim 1, wherein the surface hardness of the intermediate core layer is from 65 Shore D to 80 Shore D.

12. 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.

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

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

15. 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 blends thereof.