Back to results
US 12,337,213 B2Granted
Golf balls having cores with increased hardness gradient
AssigneeAcushnet Company
InventorsErin McDermott, Manjari Kuntimaddi, Dennis Britton
Life of this patent
Estimating the term…
Abstract
Golf balls having cores with increased hardness gradients are provided. The cores have an increased “positive” hardness gradient (or a “hard-to-soft” hardness) where the outer surface of the core is harder than the center. The increased positive hardness gradient can be achieved by introducing a water-releasing agent into the core rubber formulation during the curing process. The resulting golf balls have reduced spin and sufficient impact durability.
Claims16
A golf ball, comprising:
- a core having an outer surface and a geometric center, wherein the core is formed from a rubber composition comprising:
- a base rubber,
- a curing agent, and
- a water releasing agent selected from the group consisting of calcium sulfate dihydrate, zinc sulfate dihydrate, and a combination thereof, wherein the water releasing agent is present in the rubber composition in an amount of about 1 phr to about 3.9 phr,
- wherein the geometric center and the outer surface each has a hardness and the hardness of the geometric center ranges from about 45 Shore C to about 65 Shore C and the hardness of the outer surface ranges from about 80 Shore C to about 100 Shore C, and
- wherein the hardness of the outer surface is greater than the hardness of the geometric center to define a positive hardness gradient of at least 30 Shore C units;
- and
- a cover layer surrounding the core.
5 more elements
A golf ball, comprising:
- a dual core comprising an outer core layer disposed over an inner core layer,
- wherein at least one of the outer core layer or inner core layer has a positive hardness gradient and is formed of a rubber composition comprising:
- a base rubber,
- a curing agent,
- a water releasing agent selected from the group consisting of calcium sulfate dihydrate, zinc sulfate dihydrate, and a combination thereof, wherein the water releasing agent is present in the rubber composition in an amount of about 1 phr to about 3.9 phr,
- wherein the layer formed of the rubber composition comprises an inner surface hardness of about 40 Shore C to about 70 Shore C, an outer surface hardness of about 75 Shore C to about 105 Shore C, and the positive hardness gradient is about 30 Shore C units to about 50 Shore C units, and
- a cover layer surrounding the dual core.
4 more elements
A golf ball, comprising:
- a multi-layered core comprising a center and a plurality of core layers formed around the center,
- wherein at least one of the center or the plurality of core layers has a positive hardness gradient and is formed of a rubber composition comprising:
- a base rubber, and
- a water releasing agent selected from the group consisting of calcium sulfate dihydrate, zinc sulfate dihydrate, and a combination thereof, wherein the water releasing agent is present in the rubber composition in an amount of about 1 phr to about 3.9 phr,
- wherein the layer formed of the rubber composition comprises an inner surface hardness of about 40 Shore C to about 70 Shore C, an outer surface hardness of about 75 Shore C to about 105 Shore C, and the positive hardness gradient is about 30 Shore C units to about 50 Shore C units, and
- a cover layer surrounding the dual core.
3 more elements
Dependencies are inferred from the claim text.