# US 7,744,493 B2 · Multi-layer core golf ball

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- Number: US 7,744,493 B2
- Document ID: US7744493B2
- Status: Granted
- Kind: B2
- Application number: 12/253,602
- Filed: 2008-10-17
- Published: 2009-02-12
- Granted: 2010-06-29
- Earliest claimed: 2001-11-28
- Assignees: Acushnet Company
- Inventors: Michael J. Sullivan; Derek A. Ladd; Antonio U. DeSimas
- Web page: https://patentgrep.com/patent/US7744493B2

## CPC

- A63B 37/0003: {Golf balls}
- A63B 37/0043: {Hardness}
- A63B 37/0046: {Deflection or compression}
- A63B 37/0047: {Density; Specific gravity}
- A63B 37/005: {Cores}
- A63B 37/0062: {Hardness}
- A63B 37/0065: {Deflection or compression}
- A63B 37/0066: {Density; Specific gravity}
- A63B 37/0091: {Density distribution amongst the different ball layers}
- A63B 37/0031: {Hardness}
- A63B 37/0033: {Thickness}
- A63B 37/0045: {Thickness}
- A63B 37/0061: {Coefficient of restitution}
- A63B 37/0064: {Diameter}
- A63B 37/0076: {Multi-piece balls, i.e. having two or more intermediate layers}
- A63B: APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT (apparatus for passive exercising, massage A61H)

## Abstract

The present invention is directed to an improved golf ball displaying the desired spin profile and having a generally rigid, thermoset polybutadiene outer core surrounding a relatively soft, low compression inner core. In general, this golf ball has an inner core and at least one outer core layer surrounding the inner core. The inner core has a hardness less than a hardness of the outer core and a specific gravity less than or equal to the outer core specific gravity. Overall the inner core compression and outer core are formulated to provide a combined overall core compression of greater than about 50, preferably greater than about 70. A cover layer is provided to surround and to cover the outer core layer.

## Claims

### Claim 1

A golf ball comprising:
a multi-layer core having a diameter of greater than 1.58 inches and comprising
an inner core having a Shore C hardness of less than 80 and a compression of less than 70; and
at least one outer core layer having a Shore C hardness of greater than 90 and formed from a composition comprising greater than 35 pph of zinc diacrylate; and
two or more cover layers, at least one cover layer having a Shore D hardness of less than 65.

### Claim 2 (depends on 1)

The golf ball of claim 1, wherein the outer core layer composition comprises greater than 40 pph of zinc diacrylate.

### Claim 3 (depends on 1)

The golf ball of claim 1, wherein the multi-layer core has a diameter of greater than 1.60 inches.

### Claim 4 (depends on 1)

The golf ball of claim 1, wherein at least one cover layer is formed from a composition selected from the group consisting of cast polyurethanes, polyureas, polyurethane ionomers, thermoplastic polyurethanes, polyamides, polyesters, single-site catalyzed polymers, and partially- and fully-neutralized ionomers.