Thermoplastic dual core having a negative gradient inner core and a negative gradient outer core

Abstract

A golf ball includes an inner core layer and an outer core layer. The inner core layer is formed from a first thermoplastic material and has a geometric center hardness that is greater than its surface hardness to define a first negative hardness gradient. The outer core layer is formed from a second thermoplastic material and has an inner surface hardness greater than its outer surface hardness to define a second negative hardness gradient. Inner and outer cover layers are disposed over the outer core layer. The negative hardness gradient of the inner core layer is about −1 to −5 Shore C. The negative hardness gradient of the outer core layer is at least −1 Shore C but less than −7 Shore C. A difference between the inner core layer surface hardness and the outer core layer inner surface hardness is at least −3 Shore C.

Dependencies are inferred from the claim text.