Highly-neutralized thermoplastic copolymer center for improved multi-layer core golf ball

• US 8,007,375 B2
• Filed: 09/11/2008
• Issued: 08/30/2011
• 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: Sullivan, Michael J., Ladd, Derek A.
• Primary Examiner(s): SELLERS, ROBERT E
• Application Number:
  US12/208,631
• Publication Number:
  US 20090011860A1
• Time in Patent Office: 1,083 Days
• Field of Search: None
• US Class Current: 473/374
• CPC Class Codes: A63B 37/0004 Surface depressions or protrusions
• CPC Class Codes: A63B 37/0024 Materials other than ionomers or polyurethane
• CPC Class Codes: A63B 37/0026 Balata
• 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 37/0051 Materials other than polybutadienes; Constructional details
• CPC Class Codes: A63B 37/0056 Hollow; Gas-filled
• CPC Class Codes: A63B 37/0061 Coefficient of restitution
• CPC Class Codes: A63B 37/0062 Hardness
• CPC Class Codes: A63B 37/0064 Diameter
• CPC Class Codes: A63B 37/0065 Deflection or compression
• CPC Class Codes: A63B 37/0075 Three piece balls, i.e. cover, intermediate layer and core
• CPC Class Codes: A63B 37/0076 Multi-piece balls, i.e. having two or more intermediate layers
• CPC Class Codes: A63B 37/0091 Density distribution amongst the different ball layers
• CPC Class Codes: A63B 37/00922 whereby hardness of the cover is lower than hardness of the intermediate layers
• CPC Class Codes: A63B 37/0097 Layers interlocking by means of protrusions or inserts, lattices or the like
• CPC Class Codes: A63B 37/02 Special cores balls with finger holes A63B37/0001, golf ball cores A63B37/005
• 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

Abstract

A golf ball includes an inner core layer formed from a first rubber composition having a first Shore D hardness; an intermediate core layer formed from a second rubber composition; and a thermoplastic outer core layer having a second Shore D hardness. The outer core layer includes 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 surrounds the multi-layer core and an outer cover layer is disposed about the inner cover layer. The inner core layer hardness differs from the outer core hardness by at least 10 points.

Claims

1. A golf ball comprising:

a center formed from a first composition comprising;

an E/X/Y-type copolymer, wherein E is ethylene, X is an α

,β

-unsaturated carboxylic acid, and Y is a softening comonomer present in an amount of from 0 wt % to 50 wt % of the polymer; and

a cation source;

wherein greater than 80% of all acid groups present in the first composition are neutralized;

a cover; and

an intermediate layer disposed between the center and the cover and formed from a second composition;

wherein a sphere resulting from a combination of the center and the intermediate layer has a compression of 60 or greater; and

wherein the Shore D hardness of the first composition is less than the Shore D hardness of the second composition.

2. The golf ball of claim 1, wherein the cover comprises an inner cover layer and an outer cover layer.

3. The golf ball of claim 2, wherein the outer cover layer is formed from a polyurethane composition.

4. The golf ball of claim 2, wherein the outer cover layer is formed from a thermoplastic polyurethane composition.

5. The golf ball of claim 3, wherein the inner cover layer is formed from a thermoplastic polyurethane composition.

6. The golf ball of claim 1, wherein the first composition additionally comprises an organic acid or salt thereof, and wherein the organic acid or salt thereof is a magnesium salt of oleic acid.

7. The golf ball of claim 1, wherein greater than 90% of all acid groups present in the first composition are neutralized.

8. The golf ball of claim 1, wherein 100% of all acid groups present in the first composition are neutralized.

9. The golf ball of claim 1, wherein the second composition is a thermoset rubber composition.

10. The golf ball of claim 1, wherein the first composition has a Shore D hardness of from 30 to 80.

11. The golf ball of claim 1, wherein the second composition has a Shore D hardness of from 40 to 70.