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

• US 8,257,201 B2
• Filed: 09/21/2011
• Issued: 09/04/2012
• Est. Priority Date: 06/26/2001
• Status: Expired due to Term

• 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:
  US13/238,717
• Publication Number:
  US 20120010022A1
• Time in Patent Office: 349 Days
• Field of Search: None
• US Class Current: 473/373
• CPC Class Codes: A63B 37/0004 Surface depressions or protrusions
• CPC Class Codes: A63B 37/0027 Polyurea
• CPC Class Codes: A63B 37/0033 Thickness
• CPC Class Codes: A63B 37/0034 Deflection or compression
• CPC Class Codes: A63B 37/0037 Flexural modulus; Bending stiffness
• 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 37/0051 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 37/00622 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 37/0067 Weight; Mass
• CPC Class Codes: A63B 37/0069 Flexural modulus; Bending stiffness
• CPC Class Codes: A63B 37/0072 with a specified number of layers
• 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 37/0078 : Coefficient of restitution
• CPC Class Codes: A63B 37/008 : Diameter
• CPC Class Codes: A63B 37/0083 : Weight; Mass
• CPC Class Codes: A63B 37/0087 : Deflection or compression
• CPC Class Codes: A63B 37/0091 : Density distribution amongst the different ball layers
• CPC Class Codes: A63B 37/0092 : Hardness distribution amongst different ball 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 23/0869 : Acids or derivatives thereof
• CPC Class Codes: C08L 23/0876 : Neutralised polymers, i.e. ionomers
• CPC Class Codes: C08L 2666/02 : Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• 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 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 less than the second surface hardness by at least 5 Shore C and less than the inner surface hardness by at least 5 Shore C.

Claims

1. A golf ball comprising:

an inner core layer comprising a thermoset rubber composition and having a surface hardness;

a thermoplastic outer core layer having a 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 surface hardness of the inner core is less than the surface hardness of the outer core layer by 3 Shore D or greater and less than the inner surface hardness of the outer core layer by 3 Shore D or greater.

2. The golf ball of claim 1, wherein the surface hardness of the inner core is less than the surface hardness of the outer core layer by 5 Shore D or greater and less than the inner surface hardness of the outer core layer by 5 Shore D or greater.

3. The golf ball of claim 2, wherein the surface hardness of the inner core is less than the surface hardness of the outer core layer by 7 Shore D or greater and less than the inner surface hardness of the outer core layer by 7 Shore D or greater.

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 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.

6. 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.

7. 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.

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

9. 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.

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

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

12. The golf ball of claim 11, wherein the thermoplastic outer core layer has a thickness of 0.090 inches to 0.180 inches.