Patent ID: 9636546
Date: 2017-05-02
CPC Classifications: A63B,B32B,C08L

Claim:
1. A golf ball, comprising: a) an inner core layer formed from a first thermoplastic ionomer composition comprising an ethylene acid copolymer and containing acid groups such that 70% or less of the acid groups are neutralized; b) an outer core layer formed from a second ionomer composition comprising an ethylene acid copolymer and containing acid groups such that greater than 70% of the acid groups are neutralized, wherein the center of the inner core and surface of the outer core layer each has a hardness, and the center hardness of the inner core is greater than the surface hardness of the outer core layer, wherein the center of the inner core has a hardness in the range of 25 to 65 Shore D and the surface of the inner core has a surface hardness in the range of 30 to 70 Shore D to provide a positive hardness gradient in the inner core, and the outer core layer has a surface hardness in the range of 20 to 60 Shore D to provide a negative hardness gradient in the outer core, and wherein the first ionomer composition has a flex modulus of 20,000 psi to 150,000 psi and the second ionomer composition has a flex modulus of 1,000 to 50,000 psi, the flex modulus of the first ionomer composition being greater than the flex modulus of the second ionomer composition; and c) a cover having at least one layer.