Golf balls having dual-layered cores with metal-containing centers

• US 10,328,312 B2
• Filed: 06/21/2017
• Issued: 06/25/2019
• Est. Priority Date: 09/07/2012
• Status: Active Grant

• Current Assignee: Acushnet Company (FILA Holdings Corp.)
• Original Assignee: Acushnet Company (FILA Holdings Corp.)
• Inventors: Sullivan, Michael J., Binette, Mark L., Ladd, Derek A.
• Primary Examiner(s): Hunter, Alvin A
• Application Number:
  US15/628,707
• Publication Number:
  US 20170291071A1
• Time in Patent Office: 734 Days
• Field of Search: 473351-378
• CPC Class Codes: A63B 37/0024 Materials other than ionomers or polyurethane
• CPC Class Codes: A63B 37/0033 Thickness
• CPC Class Codes: A63B 37/0035 Density; Specific gravity
• 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 37/0047 Density; Specific gravity
• 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 37/0063 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 37/00921 whereby hardness of the cover is higher than hardness of the intermediate layers

Abstract

Multi-piece golf balls containing a dual-layered core are provided. The ball further includes single or multi-layered covers. The core structure includes a small, heavy inner core (center) having a relatively high specific gravity, and a surrounding outer core layer. The core layers may have different hardness gradients. The center of the core comprises a metal material such as copper, steel, brass, tungsten, titanium, aluminum, and combinations and alloys thereof preferably dispersed in a thermoplastic polymeric matrix. The outer core layer is preferably formed from a thermoset composition such as polybutadiene. These multi-layered core constructions with metal-containing centers have selective specific gravity relationships between the different layers. This helps provide the ball with good flight distance and spin control. The resulting balls have good resiliency and other playing performance properties.

Claims

1. A golf ball having a multi-layered core, comprising:

i) an inner core comprising a metal material, the inner core having a diameter in the range of about 0.100 to about 1.100 inches, and a specific gravity (SG_{inner core}), and an outer surface hardness (H_{center surface}) and a center hardness (H_center), the H_{center surface} being greater than the H_center to provide a positive hardness gradient;

ii) an outer core layer comprising a thermoset or thermoplastic composition and metal material, the outer core layer being disposed about the inner core and having a thickness in the range of about 0.200 to about 1.200 inches, a specific gravity (SG_{outer core}) in the range of about 4.00 to about 10.00, and an outer surface hardness (H_{outer surface of OC}) and a midpoint hardness (H_{midpoint of OC}), the H_{outer surface of OC} being greater than the H_{midpoint of OC} to provide a positive hardness gradient; and

iii) a cover layer disposed about the multi-layered core, the cover having a specific gravity (SG_cover), the SG_{inner core} being greater than the SG_{outer core} and the SG_{outer core} being substantially equal to the SG_cover.

2. The golf ball of claim 1, wherein the metal material of the inner core is a metal selected from the group consisting of copper, steel, brass, tungsten, titanium, aluminum, magnesium, molybdenum, cobalt, nickel, iron, tin, bronze, silver, gold, platinum, zinc, lithium, manganese, scandium, sodium, calcium, zirconium, vanadium, niobium, silicon, selenium, boron, chromium, and alloys and combinations thereof.

3. The golf ball of claim 1, wherein the inner core has a diameter in the range of about 0.100 to about 0.500 inches.

4. The golf ball of claim 1, wherein the inner core has a specific gravity in the range of about 6.00 to about 13.80.

5. The golf ball of claim 1, wherein the H_center is in the range of about 15 to about 74 Shore D.

6. The golf ball of claim 1, wherein the H_{midpoint of OC} is in the range of about 30 to about 85 Shore D.

7. The golf ball of claim 1, wherein the outer core layer comprises a thermoset rubber material selected from the group consisting of polybutadiene, ethylene-propylene rubber, ethylene-propylene-diene rubber, polyisoprene, styrene-butadiene rubber, polyalkenamers, butyl rubber, halobutyl rubber, polystyrene elastomers, copolymers of isobutylene and p-alkylstyrene, halogenated copolymers of isobutylene and p-alkylstyrene, copolymers of butadiene with acrylonitrile, polychloroprene, alkyl acrylate rubber, chlorinated isoprene rubber, acrylonitrile chlorinated isoprene rubber, and mixtures thereof.

8. The golf ball of claim 7, wherein the rubber material is polybutadiene.

9. The golf ball of claim 1, wherein the outer core layer comprises a thermoplastic material selected from the group consisting of ethylene acid copolymer 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.

10. The golf ball of claim 9, wherein the acid copolymer of ethylene and an α

,β

-unsaturated carboxylic acid contains acid groups such that greater than 70% of the acid groups are neutralized.

11. The golf ball of claim 10, wherein 90% or greater of the acid groups are neutralized.

12. The golf ball of claim 11, wherein the ethylene acid 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.

13. A golf ball having a multi-layered core, comprising:

i) an inner core comprising a metal material, the inner core having a diameter in the range of about 0.100 to about 1.100 inches, and a specific gravity (SG_{inner core}), and an outer surface hardness (H_{center surface}) and a center hardness (H_center), the H_{center surface} being greater than the H_center to provide a positive hardness gradient;

ii) an outer core layer comprising a thermoset or thermoplastic composition and metal material, the outer core layer being disposed about the inner core and having a thickness in the range of about 0.200 to about 1.200 inches, a specific gravity (SG_{outer core}) in the range of about 4.00 to about 10.00, and an outer surface hardness ((H_{outer surface of OC}) and a midpoint hardness (H_{midpoint of OC}), the H_{outer surface of OC} being greater than the H_{midpoint of OC} to provide a positive hardness gradient; and

iii) an inner cover layer disposed about the multi-layered core, the inner cover having a specific gravity (SG_{inner cover}); and

iv) an outer cover layer disposed about the inner cover, the outer cover having a specific gravity (SG_{outer cover});

the SG_{inner core} being greater than the SG_{outer core} and the SG_{outer core} being substantially equal to the SG_{inner cover} and SG_{outer cover}.