Golf balls having foam, hollow, or metal center and plasticized thermoplastic core layer
First Claim
1. A golf ball, comprising a core assembly and cover having at least one layer, the core assembly comprising:
- i) an inner core layer comprising a metal material, the inner core having an outer surface hardness (Hinner core surface) and a center hardness (Hinner core center), the Hinner core surface being greater than the Hinner core center to provide a positive hardness gradient, the inner core having a diameter in the range of about 0.100 to about 1.100 inches; and
ii) an outer core layer formed from a plasticized thermoplastic composition comprising;
a) an acid copolymer of ethylene and an α
,β
-unsaturated carboxylic acid, optionally including a softening monomer selected from the group consisting of alkyl acrylates and methacrylates;
b) a plasticizer; and
c) a cation source present in an amount sufficient to neutralize from about 0 to about 100% of all acid groups present in the composition; and
d) a rubber compound present in an amount greater than 50% by weight based on the combined weight of the acid copolymer and rubber;
the outer core layer being disposed about the inner core layer and having a thickness in the range of about 0.200 to about 1.200 inches and having an outer surface hardness (Houter surface of OC) and a midpoint hardness (Hmidpoint of OC), the Houter surface of OC being greater than the Hmidpoint of OC to provide a positive hardness gradient,wherein the diameter of the inner core is less than the thickness of the outer core layer and the center hardness of the inner core (Hinner core center) is in the range of about 30 Shore C to about 65 Shore C and the outer surface hardness of the outer core layer (Houter surface of OC) is in the range of about 40 Shore C to about 85 Shore C to provide a positive hardness gradient across the core assembly.
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Accused Products
Abstract
Multi-layered golf balls containing a dual-core structure are provided. The core structure includes an inner core (center) made from a foam or metal-containing composition, or it has a hollow shell construction, and the outer core layer is made of a thermoplastic composition. Preferably, the thermoplastic composition comprises: a) ethylene acid copolymer, b) plasticizer, and c) cation source. A fatty acid ester such as ethyl oleate is preferably used as the plasticizer. The core assembly preferably has a positive hardness gradient extending across the entire assembly. The core structure and resulting ball have relatively good resiliency at given compressions.
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Citations
9 Claims
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1. A golf ball, comprising a core assembly and cover having at least one layer, the core assembly comprising:
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i) an inner core layer comprising a metal material, the inner core having an outer surface hardness (Hinner core surface) and a center hardness (Hinner core center), the Hinner core surface being greater than the Hinner core center to provide a positive hardness gradient, the inner core having a diameter in the range of about 0.100 to about 1.100 inches; and ii) an outer core layer formed from a plasticized thermoplastic composition comprising; a) an acid copolymer of ethylene and an α
,β
-unsaturated carboxylic acid, optionally including a softening monomer selected from the group consisting of alkyl acrylates and methacrylates;b) a plasticizer; and c) a cation source present in an amount sufficient to neutralize from about 0 to about 100% of all acid groups present in the composition; and d) a rubber compound present in an amount greater than 50% by weight based on the combined weight of the acid copolymer and rubber; the outer core layer being disposed about the inner core layer and having a thickness in the range of about 0.200 to about 1.200 inches and having an outer surface hardness (Houter surface of OC) and a midpoint hardness (Hmidpoint of OC), the Houter surface of OC being greater than the Hmidpoint of OC to provide a positive hardness gradient, wherein the diameter of the inner core is less than the thickness of the outer core layer and the center hardness of the inner core (Hinner core center) is in the range of about 30 Shore C to about 65 Shore C and the outer surface hardness of the outer core layer (Houter surface of OC) is in the range of about 40 Shore C to about 85 Shore C to provide a positive hardness gradient across the core assembly. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification