Three-layer-core golf ball having highly-neutralized polymer outer core layer

• US 8,465,381 B2
• Filed: 03/09/2012
• Issued: 06/18/2013
• Est. Priority Date: 06/26/2001
• Status: Expired due to Fees

• Current Assignee: Acushnet Company (FILA Holdings Corp.)
• Original Assignee: Acushnet Company (FILA Holdings Corp.)
• Inventors: Rajagopalan, Murali, Sullivan, Michael J.
• Primary Examiner(s): SELLERS, ROBERT E
• Application Number:
  US13/416,132
• Publication Number:
  US 20120252603A1
• Time in Patent Office: 466 Days
• Field of Search: None
• US Class Current: 473/373
• CPC Class Codes: A63B 37/0031 Hardness
• CPC Class Codes: A63B 37/0033 Thickness
• 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 37/0047 Density; Specific gravity
• CPC Class Codes: A63B 37/0049 Flexural modulus; Bending stiffness
• CPC Class Codes: A63B 37/00622 Surface hardness
• CPC Class Codes: A63B 37/0064 Diameter
• CPC Class Codes: A63B 37/0065 Deflection or compression
• 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
• CPC Class Codes: C08L 2205/02 containing two or more polymers of the same C08L -group
• CPC Class Codes: C08L 23/08 Copolymers of ethene C08L23/16 takes precedence
• CPC Class Codes: C08L 23/0876 Neutralised polymers, i.e. ionomers
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: Y10T 428/24983 Hardness

Abstract

A golf ball including an inner core layer formed from a thermoset rubber composition and having a first surface hardness; a thermoplastic outer core layer having a second surface hardness, an inner surface hardness, and being formed from a copolymer of ethylene and an α,β-unsaturated carboxylic acid, an organic acid or salt thereof, and sufficient cation source to fully-neutralize the acid groups of the copolymer; an inner cover layer; and an outer cover layer; wherein the first surface hardness is substantially the same as the second surface hardness and the inner surface hardness.

Claims

1. A golf ball comprising:

an inner core layer comprising a thermoset rubber composition and having a first outer Shore D hardness and an outer diameter of about 1.3 inches to about 1.56 inches;

a thermoplastic outer core layer having a second outer Shore D hardness, and comprising a copolymer of ethylene and an α

,β

-unsaturated carboxylic acid, a magnesium salt of oleic acid, and sufficient cation source to fully-neutralize the acid groups of the copolymer;

an inner cover layer; and

an outer cover layer;

wherein the first outer hardness is greater than the second outer hardness and the outer core layer has a thickness of about 0.01 inches to about 0.05 inches.

2. The golf ball of claim 1, wherein the inner core has a diameter of about 1.4 inches to about 1.55 inches.

3. The golf ball of claim 1, wherein the outer core layer has a thickness of about 0.02 inches to about 0.04 inches.

4. The golf ball of claim 1, wherein the cation source is selected from a group consisting of metal cations of lithium, sodium, potassium, magnesium, calcium, barium, lead, tin, zinc, and aluminum.

5. The golf ball of claim 1, wherein the first outer surface hardness is about 46 Shore D to about 60 Shore D.

6. The golf ball of claim 5, wherein the first outer surface hardness is about 49 Shore D to about 55 Shore D.

7. The golf ball of claim 1, wherein the second outer surface hardness is about 40 Shore D to about 54 Shore D.

8. The golf ball of claim 7, wherein the second outer surface hardness is about 45 Shore D to about 51 Shore D.

9. The golf ball of claim 1, wherein the inner cover layer comprises an ionomer and the outer cover layer comprises a cast polyurethane.