Golf balls having dual cores made of polybutadiene rubber/ionomer blends

• US 9,968,831 B2
• Filed: 06/07/2016
• Issued: 05/15/2018
• Est. Priority Date: 01/10/2008
• Status: Active Grant

• Current Assignee: Acushnet Company (FILA Holdings Corp.)
• Original Assignee: Acushnet Company (FILA Holdings Corp.)
• Inventors: Sullivan, Michael J., Ladd, Derek A.
• Primary Examiner(s): Gorden, Raeann
• Application Number:
  US15/175,244
• Publication Number:
  US 20160279485A1
• Time in Patent Office: 707 Days
• Field of Search: 473373
• 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 37/0046 Deflection or compression
• CPC Class Codes: A63B 37/0047 Density; Specific gravity
• CPC Class Codes: A63B 37/00621 Centre hardness
• 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 37/0075 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

Abstract

A multi-piece golf ball comprising at least one component made of a polybutadiene rubber/ionomer resin blend is provided. The ball preferably contains a dual-core comprising an inner core and surrounding outer core layer. Preferably, the polybutadiene rubber/ionomer resin blend is used to form the outer core layer. Preferably, the outer surface hardness of the outer core layer is greater than the outer surface hardness of the inner core. The resulting ball has high resiliency and good impact durability.

Claims

1. A multi-piece golf ball, comprising:

a dual-core comprising an inner core and outer core layer, the inner core having an outer surface and geometric center and the outer core layer having an outer surface and inner surface;

the outer core being formed from a first rubber composition comprising polybutadiene rubber and ionomer resin, wherein the inner core has a center hardness and outer surface hardness, the center hardness being 85 Shore C or greater, and the outer core layer has an inner surface hardness and outer surface hardness, and wherein the center hardness of the inner core is greater than the outer surface hardness of the outer core layer and the outer surface hardness of the inner core is less than the outer surface hardness of the outer core layer; and

a cover disposed about the outer core layer.

2. The golf ball of claim 1, wherein the specific gravity of the inner core is less than or equal to the specific gravity of the outer core layer.

3. The golf ball of claim 2, wherein the inner core has a specific gravity in the range of about 0.90 to about 1.13 g/cc, and the outer core has a specific gravity in the range of about 1.00 to about 1.18 g/cc.

4. The golf ball of claim 1, wherein the acid groups of the ionomer resin are neutralized to greater than 70%.

5. The golf ball of claim 4, wherein the acid groups of the ionomer resin are neutralized to greater than 90%.

6. The golf ball of claim 1, wherein the ionomer resin is a E/X/Y copolymer, wherein E is ethylene;

X is a C₃ to C₈ α

,β

-ethylenically unsaturated mono- or dicarboxylic acid; and

Y is a softening monomer.

7. The golf ball of claim 6, wherein the copolymer is selected from the group consisting of ethylene/(meth)acrylic acid/n-butyl acrylate;

ethylene/(meth)acrylic acid/ethyl acrylate;

ethylene/(meth)acrylic acid/methyl acrylate;

ethylene/(meth)acrylic acid/n-butyl acrylate; and

ethylene/(meth)acrylic acid/isobutyl acrylate copolymers.

8. The golf ball of claim 1, wherein the ionomer composition further comprises a fatty acid or salt thereof.

9. The golf ball of claim 1, wherein the inner core layer is formed from a second rubber composition comprising polybutadiene rubber.

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

11. The golf ball of claim 1, wherein the inner and outer cover layers are formed from a composition comprising a polymer selected from the group consisting of partially and fully-neutralized ionomers;

polyesters;

polyamides;

polyamide-ethers, polyamide-esters;

polyurethanes, polyureas;

fluoropolymers;

polystyrenes;

polypropylenes and polyethylenes;

polyvinyl chlorides;

polyvinyl acetates;

polycarbonates;

polyvinyl alcohols;

polyethers;

polyimides, polyetherketones, polyamideimides; and

mixtures thereof.