Patent ID: 7749107

Claim:
A golf ball comprising: a core consisting essentially of a thermoplastic material, the core having an outer diameter of 1.51 inches to 1.59 inches and having an outer surface and a geometric center, each having a hardness; an outer cover layer; and an inner cover layer disposed between the core and the outer cover layer; wherein the thermoplastic core has been exposed to a gradient-initiating solution comprising a solvent, free radical initiator, and a reactive co-agent comprising a metal salt of an acrylic or methacrylic acid, a mono- or multi-functional acrylate or methacrylate, or having the chemical structure where R=linear, branched, C 1 -C 14 or aromatic and n=1-5, such that the hardness of the outer surface is different than the hardness of the geometric center to define a positive or negative hardness gradient of 5 Shore C or greater.