Golf balls having a foam center

• US 9,861,860 B2
• Filed: 11/07/2016
• Issued: 01/09/2018
• Est. Priority Date: 09/12/2012
• Status: Active Grant

• Current Assignee: Acushnet Company (FILA Holdings Corp.)
• Original Assignee: Acushnet Company (FILA Holdings Corp.)
• Inventors: Sullivan, Michael J., Bulpett, David A., Blink, Robert, Binette, Mark L., Comeau, Brian
• Primary Examiner(s): Gorden, Raeann
• Application Number:
  US15/344,822
• Publication Number:
  US 20170050085A1
• Time in Patent Office: 428 Days
• Field of Search: 473376
• 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 37/0044 Hardness gradient
• CPC Class Codes: A63B 37/0045 Thickness
• CPC Class Codes: A63B 37/0051 Materials other than polybutadienes; Constructional details
• CPC Class Codes: A63B 37/0054 Substantially rigid, e.g. metal
• CPC Class Codes: A63B 37/0058 Polyurethane
• CPC Class Codes: A63B 37/006 Physical properties
• CPC Class Codes: A63B 37/0063 Hardness gradient
• CPC Class Codes: A63B 37/0064 Diameter
• 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 37/0092 Hardness distribution amongst different ball layers
• CPC Class Codes: A63B 45/00 Apparatus or methods for manufacturing balls working of plastics or substances in a plastic state B29
• CPC Class Codes: C08K 5/098 Metal salts of carboxylic acids
• CPC Class Codes: C08L 23/0876 Neutralised polymers, i.e. ionomers

Abstract

Multi-layered golf balls containing a dual-core structure are provided. The core structure includes an inner core (center) comprising a foam composition, preferably foamed polyurethane. The outer core layer is preferably formed from a non-foamed composition selected from thermoset compositions and thermoplastic compositions. The core layers have different hardness and specific gravity levels. The specific gravity (density) of the foam inner core is preferably less than the density of the outer core layer.

Claims

1. A core assembly for a golf ball, comprising:

an inner core layer formed from a foamed composition, the inner core layer having a diameter of from 0.100 inches to 1.100 inches and an outer surface hardness (H_{inner core surface}) and a center hardness (H_{inner core center}), the H_{inner core surface} being the same or less than the H_{inner core center} to provide a zero or negative hardness gradient; and

an outer core layer formed from a non-foamed composition, the outer core layer having a thickness of from 0.100 inches to 0.750 inches and an outer surface hardness (H_{outer surface of OC}) and an inner surface hardness (H_{inner surface of OC}), the H_{outer surface of OC} being greater than the H_{inner surface of OC} to provide a positive hardness gradient;

wherein the specific gravity of the outer core layer is greater than the specific gravity of the inner core layer; and

wherein at least one of the inner core layer composition and the outer core layer composition is a highly neutralized polymer composition comprising;

an acid copolymer of ethylene and an α

,β

-unsaturated carboxylic acid, optionally including a softening monomer selected from the group consisting of alkyl acrylates and methacrylates;

a non-acid polymer selected from the group consisting of polyolefins, polyamides, polyesters, polyethers, polyurethanes, metallocene-catalyzed polymers, single-site catalyst polymerized polymers, ethylene propylene rubber, ethylene propylene diene rubber, styrenic block copolymer rubbers, alkyl acrylate rubbers, and functionalized derivatives thereof;

an organic acid or salt thereof; and

a cation source present in an amount sufficient to neutralize greater than 80% of all acid groups present in the composition.

2. The core assembly of claim 1, wherein the acid copolymer of ethylene and an α

,β

-unsaturated carboxylic acid does not include a softening monomer, the non-acid polymer is an alkyl acrylate rubber selected from ethylene-alkyl acrylates and ethylene-alkyl methacrylates, and the organic acid salt is magnesium oleate present in an amount of 20 parts or greater per 100 parts of acid copolymer and non-acid copolymer combined.

3. The core assembly of claim 1, wherein the cation source is present in an amount sufficient to neutralize 110% or greater of all acid groups present in the composition.

4. The core assembly of claim 1, wherein the outer core layer composition is thermoplastic.

5. The core assembly of claim 1, wherein the outer core layer composition is thermoset, and wherein the inner core layer composition is the highly neutralized polymer composition.