Dual core golf ball having negative-hardness-gradient thermoplastic inner core and steep positive-hardness-gradient thermoset outer core layer

摘要

A golf ball includes an inner core layer formed from a thermoplastic material comprising a 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 fully-neutralize the acid groups of the copolymer by 80% or greater. The inner core has a geometric center hardness less than its surface hardness to define a positive hardness gradient. An outer core layer is formed over the inner core and is formed from a substantially homogenous thermoset composition. The outer core layer has an interior hardness substantially less than an outer surface hardness to define a steep positive hardness gradient. An inner cover layer and an outer cover layer are formed over the outer core layer.

主权项

1. A golf ball comprising:
an inner core layer consisting of a thermoplastic material and having a geometric center hardness less than a surface hardness to define a positive hardness gradient; 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 steep positive hardness gradient of at least 25 Shore C points; 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.