IP Library › Granted Patent US 8,337,330
Granted Patent B2
US 8,337,330 · App. 13/438,947 · Granted Dec 25, 2012

Multi-piece golf ball comprising low hardness gradient core

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Quick Facts
Patent No.
US 8,337,330
App. No.
13/438,947
Filed
Apr 4, 2012
Granted
Dec 25, 2012
Kind
B2
Art Unit
3711
USPC
473/373
Abstract

A golf ball includes a single core formed from a substantially homogenous rubber composition, an inner cover disposed about the core, and an outer cover. The inner cover includes an ionomeric material and has a hardness of about 60 Shore D or greater. The outer cover layer is disposed about the inner cover layer, is formed from a castable polyurea or polyurethane, and has a material hardness of about 60 Shore D or less. The outer surface of the core has a trans content of about 12% or less and a hardness of about 71 to 88 Shore C, the geometric center of the core has a trans content of about 10% or less and a hardness of about 70 to 80 Shore C, and the core surface hardness is greater than the geometric center hardness by about 1 to 10 Shore C to define a shallow positive hardness gradient.

Claims (13)

1. A golf ball comprising:

a single core having an outer surface and a geometric center and being formed from a substantially homogenous rubber composition;

an inner cover layer disposed about the core, the inner cover comprising an ionomeric material and having a material hardness of about 60 Shore D or greater; and

an outer cover layer disposed about the inner cover layer, the outer cover comprising a polyurea or a polyurethane and having a material hardness of about 60 Shore D or less;

wherein the outer surface has a trans content of about 12% or less and a hardness of about 68 Shore C to about 80 Shore C, the geometric center has a trans content of about 10% or less and a hardness of about 68 Shore C to about 80 Shore C, and the core surface hardness is greater than the geometric center hardness by about 1 to 10 Shore C to define a shallow positive hardness gradient.

2. The golf ball of claim 1 , wherein the positive hardness gradient is about 2 to 8 Shore C.

3. The golf ball of claim 2 , wherein the positive hardness gradient is about 2.5 to 7 Shore C.

4. The golf ball of claim 1 , wherein the core has an outer diameter of about 1.45 to about 1.62 inches.

5. The golf ball of claim 4 , wherein the core has an outer diameter of about 1.50 to about 1.58 inches.

6. The golf ball of claim 1 , wherein the hardness of the core geometric center is about 72 to 78 Shore C.

7. The golf ball of claim 1 , wherein the hardness of the core surface is about 73 to 80 Shore C.

8. The golf ball of claim 7 , wherein core surface hardness is about 74 to 78 Shore C.

9. The golf ball of claim 1 , wherein the outer surface has a trans content of about 10% or less and the geometric center has a trans content of about 8% or less.