Patent ID: 8182369

Claim:
A golf ball comprising: a core comprising a thermoplastic inner core and a thermoset outer core layer, the inner core having a surface hardness of 43 Shore D to about 65 Shore D and a center hardness of about 30 Shore D to 43 Shore D and is less than the surface hardness to define a first positive hardness gradient; and a cover comprising an inner cover layer and an outer cover layer; wherein the thermoplastic inner core comprises 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, and the outer core layer comprises a polybutadiene rubber and has a surface hardness greater than an interior hardness by about 6 to 11 Shore D points to define a shallow positive hardness gradient.