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 thermoplastic composition and having a center hardness (H center ) of 60 Shore C or greater, and an outer surface hardness (H center surface ) of 80 Shore C or greater;
an outer core layer formed from a highly neutralized polymer composition and having a material hardness (H outer core material ) of 35 Shore D or greater;
an inner cover layer formed from a thermoplastic composition having a material hardness (H inner cover material ) of 95 Shore C or less;
an intermediate cover layer formed from a thermoplastic composition having a material hardness (H intermediate cover material ) of from 80 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;
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.
3. The golf ball of claim 1 , wherein the inner core layer has a diameter of 1.200 inches or greater.
4. The golf ball of claim 1 , wherein H intermediate cover material is greater than the H outer core material .
5. The golf ball of claim 1 , wherein the thermoplastic composition of the inner cover layer is a partially neutralized ionomer composition comprising an ethylene acid copolymer having acid groups such that the amount of neutralized acid groups is less than 80%.
6. The golf ball of claim 1 , wherein the thermoplastic composition of the inner cover layer is an ionomer composition comprising an ethylene acid copolymer having acid groups wherein the amount of neutralized acid groups is 80% or greater.
7. The golf ball of claim 1 , wherein the thermoplastic composition of the intermediate cover layer is a partially neutralized ionomer composition comprising an ethylene acid copolymer having acid groups wherein the amount of neutralized acid groups is less than 80%.
8. The golf ball of claim 1 , wherein the thermoplastic composition of the intermediate cover layer is an ionomer composition comprising an ethylene acid copolymer having acid groups wherein the amount of neutralized acid groups is 80% or greater.
9. The golf ball of claim 1 , wherein H inner cover material is 75 Shore C or less.