Very-low melt flow thermoplastic composition for golf ball core layers

• US 8,337,331 B2
• Filed: 05/20/2009
• Issued: 12/25/2012
• Est. Priority Date: 01/10/2008
• Status: Active Grant

• Current Assignee: Acushnet Company (FILA Holdings Corp.)
• Original Assignee: Acushnet Company (FILA Holdings Corp.)
• Inventors: Bulpett, David A., Blink, P. Robert, Binette, Mark L., Comeau, Brian, Sullivan, Michael J.
• Primary Examiner(s): Gorden, Raeann
• Application Number:
  US12/469,381
• Publication Number:
  US 20090227394A1
• Time in Patent Office: 1,315 Days
• Field of Search: 473/376
• 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 37/00622 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

A golf ball including an inner core layer formed from a first thermoset rubber composition and having a diameter of about 1.25 to 1.58 inches; an outer core layer formed from a second thermoset rubber composition; and an intermediate core layer disposed between the inner core layer and outer core layer. The intermediate core layer is formed from a thermoplastic composition having a first melt flow index at 280° C. under a 10-kg load of less than about 35 g/10 min and has a thickness of about 0.005 inches to 0.10 inches and a surface hardness of greater than about 60 Shore D. A cover layer having a thickness of about 0.01 to 0.05 inches and a surface hardness of about 60 Shore D or less is formed around the core.

Claims

1. A golf ball comprising:

an inner core layer formed from a first thermoset rubber composition and having a diameter of about 1.25 inches to 1.58 inches;

an outer core layer formed from a second thermoset rubber composition;

an intermediate core layer disposed between the inner core layer and outer core layer, the intermediate core layer comprising a thermoplastic composition having a first melt flow index at 280°

C. under a 10-kg load of less than about 35 g/10 min and having a thickness of about 0.005 inches to 0.10 inches and a surface hardness of greater than about 60 Shore D; and

a cover layer having a thickness of about 0.01 inches to 0.05 inches and a surface hardness of about 60 Shore D or less.

2. The golf ball of claim 1, wherein the first melt flow index is less than about 20 g/10 min.

3. The golf ball of claim 2, wherein the first melt flow index is less than about 10 g/10 min.

4. The golf ball of claim 1, wherein the thermoplastic composition has a second melt flow index at 265°

C. under a 5-kg load of less than about 10 g/10 min.

5. The golf ball of claim 4, wherein the second melt flow index is less than about 5 g/10 min.

6. The golf ball of claim 1, wherein the thermoplastic composition has a third melt flow index at 190°

C. under a 2.16-kg load of less than about 2 g/10 min.

7. The golf ball of claim 6, wherein the third melt flow index at is less than about 1 g/10 min.

8. The golf ball of claim 1, wherein the thermoplastic composition comprises an ionomer.

9. The golf ball of claim 8, wherein the ionomer is neutralized by a metal cation to 70 wt % or greater.

10. The golf ball of claim 9, wherein the ionomer is neutralized by a metal cation to 80 wt % or greater.

11. The golf ball of claim 10, wherein the ionomer is neutralized by a metal cation to 90 wt % or greater.

12. The golf ball of claim 1, wherein the inner core layer has a center hardness of about 40 Shore C to 75 Shore C and a surface hardness of about 80 Shore C or greater.

13. The golf ball of claim 12, wherein the outer core layer has a surface hardness of about 90 Shore C or greater.

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

15. The golf ball of claim 1, wherein the inner core layer has a diameter of about 1.40 inches to 1.50 inches.

16. The golf ball of claim 1, wherein the intermediate core layer has a thickness of about 0.04 inches to 0.06 inches and the outer core layer has a thickness of about 0.03 inches to 0.04 inches.

17. The golf ball of claim 1, wherein the cover layer has a thickness of about 0.025 inches to 0.035 inches.

18. The golf ball of claim 1, wherein the intermediate core layer has a surface hardness of about 65 Shore D to 80 Shore D.

19. The golf ball of claim 1, wherein the inner core layer has a positive hardness gradient wherein the difference between the center hardness and the surface hardness of the inner core layer is from 10 to 45 Shore C.

20. A golf ball comprising:

an inner core layer comprising a first diene rubber composition and having a diameter of from 1.35 inches to 1.49 inches, a hardness at the geometric center of about 40 Shore C to 75 Shore C, and a surface hardness of about 80 Shore C to 90 Shore C;

an outer core layer formed from a second diene rubber composition and having a thickness of 0.01 inches to 0.10 inches and a surface hardness of 75 Shore C or greater;

an intermediate core layer disposed between the inner core layer and the outer core layer, the intermediate core layer comprising a thermoplastic ionomeric composition neutralized to 80 wt % or greater, and having a thickness of 0.005 inches to 0.10 inches and a surface hardness of greater than 60 Shore D; and

a cover layer having a thickness of from 0.01 inches to 0.05 inches and a surface hardness of 60 Shore D or less, the cover comprising polyurethane or polyurea;

wherein the thermoplastic ionomeric composition has a first melt flow index at 280°

C. under a 10-kg load of less than about 20 g/10 min, a second melt flow index at 265°

C. under a 5-kg load of less than about 5 g/10 min, and a third melt flow index at 190°

C. under a 2.16-kg load of less than about 1 g/10 min.