# US 9,750,983 B2 · Golf balls having multi-layered core with thermoplastic outer layer

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- Number: US 9,750,983 B2
- Document ID: US9750983B2
- Status: Granted
- Kind: B2
- Application number: 14/736,485
- Filed: 2015-06-11
- Published: 2015-10-01
- Granted: 2017-09-05
- Earliest claimed: 2012-11-01
- Assignees: Acushnet Company
- Applicants: Acushnet Company
- Inventors: Michael J. Sullivan; Mark L. Binette
- Web page: https://patentgrep.com/patent/US9750983B2

## CPC

- A63B 37/0076: {Multi-piece balls, i.e. having two or more intermediate layers}
- A63B 37/0033: {Thickness}
- A63B 37/0044: {Hardness gradient}
- A63B 37/0045: {Thickness}
- A63B 37/0047: {Density; Specific gravity}
- A63B 37/0051: {Materials other than polybutadienes; Constructional details}
- A63B 37/0054: {Substantially rigid, e.g. metal}
- A63B 37/00621: {Centre hardness}
- A63B 37/00622: {Surface hardness}
- A63B 37/0063: {Hardness gradient}
- A63B 37/0064: {Diameter}
- A63B 37/0066: {Density; Specific gravity}
- A63B 37/0077: {Physical properties}
- A63B 37/0091: {Density distribution amongst the different ball layers}
- A63B 37/0092: {Hardness distribution amongst different ball layers}
- A63B 37/0024: {Materials other than ionomers or polyurethane}
- A63B 37/0027: {Polyurea}
- A63B 37/0039: {characterised by the material}
- A63B: APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT (apparatus for passive exercising, massage A61H)

## Abstract

Multi-piece golf balls containing a multi-layered core structure are provided. The core structure includes a small, heavy inner core (center) having a relatively high specific gravity, an intermediate core layer, and a surrounding outer core layer. The layers of the core structure may have different hardness gradients. In one preferred embodiment, each core layer has a positive hardness gradient. The center of the core comprises a metal material such as copper, steel, brass, tungsten, titanium, aluminum, and alloys thereof. The intermediate core layer is preferably formed from a thermoset composition such as polybutadiene rubber, and the outer core layer is preferably formed from a thermoplastic composition such as an ethylene acid copolymer. The resulting ball has high resiliency and good spin control.

## Claims

### Claim 1

A golf ball, comprising:
a multi-layered core including i) an inner core comprising a metal material, wherein the inner core has a diameter in the range of about 0.100 to about 0.500 inches and specific gravity (SGinner) in the range of about 1.60 to about 6.25 g/cc, and an outer surface hardness (Hcenter surface) and a center hardness (Hcenter material), the Hcenter surface being greater than the Hcenter material to provide a positive hardness gradient;
ii) an intermediate core layer comprising a thermoset material, the intermediate layer being disposed about the inner core and having a thickness in the range of about 0.050 to about 0.400 inches, and an outer surface hardness (Houter surface of IC) and an inner surface hardness (Hinner surface of IC), the Houter surface of IC being greater than the Hinner surface of IC to provide a positive hardness gradient; and
iii) an outer core layer comprising a thermoplastic material, the outer core layer being disposed about the intermediate core layer and having a thickness in the range of about 0.200 to about 0.750 inches, a specific gravity (SGouter), and an outer surface hardness ((Houter surface of OC) of 42 to 92 Shore C and an inner surface hardness (Hinner surface of OC) of 40 to 89 Shore C, the Houter surface of OC being greater than the Hinner surface of OC to provide a positive hardness gradient, wherein the SGinner is greater than the SGouter, and the volume of the outer core layer is greater than the volume of each of the inner core and intermediate core layers; and
a cover having at least one layer disposed about the multi-layered core.

### Claim 2 (depends on 1)

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, zinc, barium, bismuth, bronze, silver, gold, and platinum, and alloys and combinations thereof.

### Claim 3 (depends on 1)

The golf ball of claim 1, wherein the outer core layer has a thickness in the range of about 0.250 to about 0.750 inches and specific gravity in the range of about 0.60 to about 2.90 g/cc.