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

• US 8,152,654 B2
• Filed: 09/26/2008
• Issued: 04/10/2012
• Est. Priority Date: 06/26/2001
• Status: Active Grant

• 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:
  US12/238,525
• Publication Number:
  US 20090023517A1
• Time in Patent Office: 1,292 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 surface hardness;

a thermoplastic outer core layer having a second outer surface hardness, an inner surface hardness, and comprising 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 outer surface hardness is substantially the same as the second outer surface hardness and the inner surface hardness.

2. 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.

3. The golf ball of claim 1, wherein the organic acid salt comprises an organic acid selected from the group consisting of aliphatic organic acids, aromatic organic acids, saturated mono- or multi-functional organic acids, unsaturated mono- or multi-functional organic acids, and multi-unsaturated mono- or multi-functional organic acids.

4. The golf ball of claim 1, wherein the organic acid comprises stearic acid, behenic acid, erucic acid, oleic acid, linoelic acid or dimerized derivatives thereof.

5. The golf ball of claim 1, wherein the organic acid salt comprises a cation selected from the group consisting of barium, lithium, sodium, zinc, bismuth, chromium, cobalt, copper, potassium, strontium, titanium, tungsten, magnesium, cesium, iron, nickel, silver, aluminum, tin, and calcium.

6. The golf ball of claim 1, wherein the outer cover is a castable polyurea or polyurethane.

7. The golf ball of claim 1, wherein the inner cover layer comprises a polyurethane, a polyurea, a polyurethane-urea hybrid, a polyurea-urethane hybrid, or an ionomer.

8. The golf ball of claim 1, wherein the inner core has a diameter of 0.8 inches to 1.4 inches.

9. The golf ball of claim 1, wherein the thermoplastic outer core layer has a thickness of 0.040 inches or greater.

10. The golf ball of claim 9, wherein the thermoplastic outer core layer has a thickness of 0.090 inches to 0.180 inches.