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US 12,594,465 B2Granted
Golf balls having increased impact durability
AssigneeAcushnet Company
InventorsErin McDermott, Manjari Kuntimaddi
Life of this patent
Estimating the term…
Abstract
Golf balls having cores with increased hardness gradients and improved impact durability 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 cores are formed from rubber formulations including combinations of a terpene-based resin, ethylene-propylene-diene (EPDM) rubber, and/or a water releasing agent. The resulting golf balls have increased impact durability and resilience.
Claims18
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 comprising ethylene-propylene-diene (EPDM) rubber in an amount of about 3 phr to about 15 phr,
- a free radical initiator,
- a terpene-based resin,
- a water releasing agent comprising a metal sulfate hydrate having one to four waters of hydration,
- wherein the geometric center and the outer surface each has a hardness and the hardness of the outer surface is greater than the hardness of the geometric center to define a positive Shore C hardness gradient of greater than 35 and less than 50, and
- wherein the amount of terpene-based resin present in the rubber composition is related to the positive Shore C hardness gradient, according to Equation III:
- TBR
- c
- 1
- -
- 1
- H
- G
-
- r
- ≤
- 750
- ,
- (
- III
- )
- where TBRC represents the amount of terpene-based resin in the rubber formulation in parts per hundred and HGr represents the positive Shore C hardness gradient;
- and
- a cover layer surrounding the core.
22 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 the inner core layer is formed of a rubber composition comprising:
- a base rubber comprising EPDM rubber in an amount of about 3 phr to about 15 phr,
- a free radical initiator,
- a terpene-based resin comprising a terpene polymer, a terpene-phenol copolymer, a terpene-styrene copolymer, a terpene-phenol-styrene copolymer, a hydrogenated terpene-phenol copolymer, a hydrogenated terpene-styrene copolymer, a hydrogenated terpene-phenol-styrene copolymer, or combinations thereof,
- a water releasing agent comprising a metal sulfate hydrate having one to four waters of hydration,
- wherein the layer formed of the rubber composition has an outer surface and a geometric center, each having a hardness, and the hardness of the outer surface is greater
- than the hardness of the geometric center to define a positive Shore C hardness gradient of greater than 35 and less than 50, and
- wherein the amount of terpene-based resin present in the rubber composition is related to the positive Shore C hardness gradient, according to Equation III:
- TBR
- c
- 1
- -
- 1
- H
- G
-
- r
- ≤
- 750
- ,
- (
- III
- )
- where TBRC represents the amount of terpene-based resin in the rubber formulation in parts per hundred and HGr represents the positive Shore C hardness gradient;
- and
- a cover layer surrounding the dual core.
24 more elements
A golf ball, comprising:
- a multi-layered core comprising a center, an inner core layer disposed about the center, and an outer core layer disposed about the inner core layer, wherein at least one of the center, inner core layer, or outer core layer is formed of a rubber composition comprising:
- a base rubber comprising EPDM rubber in an amount of about 3 phr to about 15 phr,
- a free radical initiator,
- a terpene-based resin comprising a terpene polymer, a terpene-phenol copolymer, a terpene-styrene copolymer, a terpene-phenol-styrene copolymer, a hydrogenated terpene-phenol copolymer, a hydrogenated terpene-styrene copolymer, a hydrogenated terpene-phenol-styrene copolymer, or combinations thereof,
- a water releasing agent comprising a metal sulfate hydrate having one to four waters of hydration, 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 has an outer surface and a geometric center, each having a hardness, and the hardness of the outer surface is greater than the hardness of the geometric center to define a positive Shore C hardness gradient of greater than 35 and less than 50, and
- wherein the amount of terpene-based resin present in the rubber composition is related to the positive Shore C hardness gradient, according to Equation III:
- TBR
- c
- 1
- -
- 1
- H
- G
-
- r
- ≤
- 750
- ,
- (
- III
- )
- where TBRC represents the amount of terpene-based resin in the rubber formulation in parts per hundred and HGr represents the positive Shore C hardness gradient;
- and
- a cover layer surrounding the multi-layered core.
22 more elements
Dependencies are inferred from the claim text.