Dual core golf ball having negative-hardness-gradient thermoplastic inner core and steep positive-hardness-gradient thermoset outer core layer
AssigneeAcushnet Company
InventorsMichael J. Sullivan, Brian Comeau, William B. Lacy
Life of this patent
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Abstract
A golf ball comprising a thermoplastic inner core layer that has a geometric center hardness greater than its surface hardness to define a “negative” hardness gradient. An outer core layer is disposed about the inner core and is formed from a substantially homogenous thermoset composition, typically rubber, and has an inner surface hardness substantially less than its outer surface hardness to define a “positive” hardness gradient. An inner cover layer is disposed about the outer core layer and an outer cover layer is disposed about the inner cover layer.
Claims15
A golf ball comprising:
- an inner core layer consisting essentially of a thermoplastic material and having a geometric center hardness greater than a surface hardness to define a negative hardness gradient;
- an outer core layer disposed about the inner core, the outer core being formed from a substantially homogenous thermoset composition and having an inner surface hardness substantially less than an outer surface hardness to define a positive hardness gradient;
- an inner cover layer disposed outer core layer;
- and
- an outer cover layer disposed about the inner cover layer.
A golf ball comprising:
- an inner core layer consisting of a thermoplastic material and having a geometric center hardness greater than a surface hardness to define a negative hardness gradient between −1 Shore C and −5 Shore C;
- 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 an inner surface hardness less than an outer surface hardness to define a substantially positive hardness gradient of at least 25 Shore C;
- 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.
A golf ball comprising:
- an inner core layer consisting of a thermoplastic material and having a geometric center hardness greater than a surface hardness to define a negative hardness gradient between −1 Shore C and −5 Shore C, the center hardness being about 90 Shore C to about 100 Shore C and the surface hardness being about 85 Shore C to about 95 Shore C;
- 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 an inner surface hardness less than an outer surface hardness to define a positive hardness gradient of at least 25 Shore C, the inner surface being about 50 Shore C to about 60 Shore C and the surface being about 82 Shore C to about 92 Shore C;
- 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.
Dependencies are inferred from the claim text.