DUAL CORE GOLF BALL HAVING A SHALLOW "POSITIVE HARDNESS GRADIENT" THERMOPLASTIC INNER CORE AND A STEEP "POSITIVE HARDNESS GRADIENT" THERMOSET OUTER CORE LAYER
First Claim
1. A golf ball comprising:
- an inner core layer comprising a thermoplastic highly-neutralized ionomer comprising a copolymer of ethylene and an α
,β
-unsaturated carboxylic acid, an organic acid or salt thereof, and sufficient cation source to neutralize the acid groups of the copolymer by 80% or greater, and having a geometric center hardness less than a surface hardness to define a first hardness gradient;
an outer core layer disposed about the inner core, the outer core being formed from a homogenous thermoset composition and having an interior hardness substantially less than an outer surface hardness to define a second hardness gradient;
an inner cover layer disposed about outer core layer; and
an outer cover layer disposed about the inner cover layer,wherein the first and second hardness gradients are positive and a slope of the second hardness gradient is greater than a slope of the first hardness gradient.
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Accused Products
Abstract
A golf ball including a highly-neutralized thermoplastic inner core layer having a geometric center hardness less than a surface hardness to define a first hardness gradient, an outer core layer formed from a homogenous thermoset composition and having an interior hardness substantially less than an outer surface hardness to define a second hardness gradient, an inner cover layer, and an outer cover layer. Both the first and second hardness gradients are positive and a slope of the second hardness gradient is greater than a slope of the first hardness gradient to define a shallow hardness gradient inner core and a steep hardness gradient outer core layer.
39 Citations
18 Claims
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1. A golf ball comprising:
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an inner core layer comprising a thermoplastic highly-neutralized ionomer comprising a copolymer of ethylene and an α
,β
-unsaturated carboxylic acid, an organic acid or salt thereof, and sufficient cation source to neutralize the acid groups of the copolymer by 80% or greater, and having a geometric center hardness less than a surface hardness to define a first hardness gradient;an outer core layer disposed about the inner core, the outer core being formed from a homogenous thermoset composition and having an interior hardness substantially less than an outer surface hardness to define a second hardness gradient; an inner cover layer disposed about outer core layer; and an outer cover layer disposed about the inner cover layer, wherein the first and second hardness gradients are positive and a slope of the second hardness gradient is greater than a slope of the first hardness gradient. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A golf ball comprising:
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an inner core layer consisting of a thermoplastic material and having a geometric center hardness less than a surface hardness to define a first positive hardness gradient of less than 10 Shore D points; an outer core layer disposed about the inner core, the outer core being formed from a substantially homogenous thermoset composition comprising a diene rubber and having a second positive hardness gradient of 10 Shore D points or greater; a cover layer disposed outer core layer, the cover layer comprising an inner cover layer comprising an ionomer and an outer cover layer comprising a castable polyurethane or polyurea material. - View Dependent Claims (16, 17, 18)
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Specification