Multi-layer golf ball
Multi-piece golf balls having a multi-layered solid core and multi-layered cover are provided.
1. A golf ball consisting essentially of:
an inner core layer formed from a thermoset rubber composition and having a center hardness (H center ) of 25 Shore C or greater, and an outer surface hardness (H center surface) of 40 Shore C or greater;
an outer core layer formed from a highly neutralized polymer composition and having an outer surface hardness (H outer core surface ) of 45 Shore C or greater;
an inner cover layer formed from a thermoplastic composition and having an outer surface hardness (H inner cover surface ) of 50 Shore C or greater;
an intermediate cover layer formed from a thermoplastic composition and having an outer surface hardness (H intermediate cover surface ) of 60 Shore C or greater; and
an outer cover layer formed from a composition selected from the group consisting of ionomeric and non-ionomeric E/X- and E/X/Y-type acid copolymers of ethylene (E), a C 3 -C 8 α,β-ethylenically unsaturated carboxylic acid (X), and an optional softening monomer (Y); and blends of two or more thereof; and having an outer surface hardness (H outer cover surface );
wherein the golf ball has an overall hardness gradient such that
H center surface <H outer core surface <H inner cover surface <H intermediate cover surface <H outer cover surface .
2. The golf ball of claim 1 , wherein the inner core layer has a diameter of 0.500 inches or greater.