Multi-layer core golf ball

Patent metadata

Field	Value
Publication number	US-9586097-B2
Application number	US-201514852591-A
Country	US
Kind code	B2
Filing date	Sep 13, 2015
Priority date	Aug 5, 2013
Publication date	Mar 7, 2017
Grant date	Mar 7, 2017

Abstract

Golf balls having a very high positive gradient multilayer core are provided. The multilayer core includes an outer core layer and a very soft, low compression inner core layer. The inner core layer is formed from an unfoamed composition and has a center hardness that is at least 40 Shore C points less than the outer surface hardness of the outer core layer.

First claim

What is claimed is:

1. A golf ball comprising a core and a cover, wherein the core comprises:
a solid inner core layer formed from an unfoamed first polybutadiene composition and having a diameter of 1.10 inch or less and a center Shore C hardness (H center ) of 40 or less,
one or more optional intermediate core layers, and
an outer core layer formed from a second polybutadiene composition and having a thickness of 0.150 inches or greater and an outer surface Shore C hardness (H outer surface ) of 80 or greater,
wherein H outer surface >H center , and H outer surface −H center ≧40, and
wherein the core has a gradient quotient, Q, of from 7 to 12, as defined by the equation:

G
+
T

10
×
COR

=
Q

where G is the hardness gradient of the core in Shore C as defined by H outer surface minus H center , T is the percent of trans-polybutadiene isomer at the surface of the outer core layer, and COR is the coefficient of restitution of the core measured at an incoming velocity of 125 ft/s; and

wherein the hardness gradient, G, is from 60 to 90; the percent of trans-polybutadiene isomer at the surface of the outer core layer, T, is from 1 to 5; and the COR of the core is from 0.790 to 0.840.

2. The golf ball of claim 1 , wherein H outer surface −H center ≧45.

3. The golf ball of claim 1 , wherein H outer surface −H center ≧55.

4. The golf ball of claim 1 , wherein H outer surface −H center ≧60.

5. The golf ball of claim 1 , wherein the core has an overall compression of ≧70.

6. The golf ball of claim 1 , wherein the inner core layer composition is a thermoset composition consisting essentially of:
polybutadiene;
from 0.1 phr to 2.0 phr of a peroxide;
optionally 5 phr or less of a metal oxide;
optionally 5 phr or less of a metal coagent;
optionally 5 phr or less of a metal carbonate; and
optionally one or more additional components selected from the group consisting of fillers, colorants, and antioxidants.

Assignees

• Acushnet Co

Inventors

• Sullivan Michael J
• Goguen Douglas S
• Comeau Brian

Classifications

• A63B37/0092 Primary

  Hardness distribution amongst different ball layers · CPC title

• A63B37/0039

  characterised by the material · CPC title

• A63B37/0045

  Thickness · CPC title

• A63B37/0075

  Three piece balls, i.e. cover, intermediate layer and core · CPC title

• A63B37/0076

  Multi-piece balls, i.e. having two or more intermediate layers · CPC title