GOLF BALLS COMPRISING HIGHLY-NEUTRALIZED ACID POLYMERS
Multi-layer golf balls comprising a center, intermediate layer, and cover are disclosed. At least one layer of the ball is formed from a highly-neutralized acid copolymer composition.
1 . A golf ball comprising:
a center formed from a first composition comprising:
an E/X/Y-type copolymer, wherein E is ethylene, X is an α,β-unsaturated carboxylic acid, and Y is a softening comonomer present in an amount of from 0 wt % to 50 wt % of the polymer; and
a cation source;
wherein greater than 80% of all acid groups present in the first composition are neutralized;
a cover; and
an intermediate layer disposed between the center and the cover and formed from a second composition;
wherein the center is a single piece comprising a central portion and a plurality of projections formed thereon.
2 . The golf ball of claim 1 , wherein the projections of the center are spaced from one another to define gaps there between.
3 . The golf ball of claim 1 , wherein the projections are shaped such that the center is substantially spherically symmetrical.
4 . The golf ball of claim 2 , wherein the intermediate layer includes a first section and a second section, wherein the first section fills the gaps between the projections.
5 . The golf ball of claim 1 , wherein the intermediate layer has an outer diameter of from 1.00 inches to 1.64 inches.
6 . The golf ball of claim 4 , wherein the intermediate layer has a substantially spherical outer surface.
7 . The golf ball of claim 1 , wherein a sphere resulting from a combination of the center and the intermediate layer has a compression of 60 or greater.
8 . The golf ball of claim 1 , wherein the Shore D hardness of the first composition is less than the Shore D hardness of the second composition.
9 . The golf ball of claim 1 , wherein the difference between the elastic modulus of the first composition and the elastic modulus of the second composition is 10% or greater.
10 . The golf ball of claim 1 , wherein the difference between the Bashore resilience of the first composition and the Bashore resilience of the second composition is 10% or greater.
11 . The golf ball of claim 1 , wherein the difference between the Shore D hardness of the first composition and the Shore D hardness of the second composition is 10 or greater, the difference between the elastic modulus of the first composition and the elastic modulus of the second composition is 10% or greater, and the difference between the Bashore resilience of the first composition and the Bashore resilience of the second composition is 10% or greater.
12 . The golf ball of claim 1 , wherein the first composition has a Shore D hardness of from 30 to 80.
13 . The golf ball of claim 1 , wherein the second composition has a Shore D hardness of from 40 to 70.
14 . The golf ball of claim 1 , wherein the first composition has an elastic modulus of from 5,000 psi to 100,000 psi.
15 . The golf ball of claim 1 , wherein the first composition has a Bashore resilience of greater than 30%.
16 . The golf ball of claim 1 , wherein the Shore D hardness of the first composition is less than the Shore D hardness of the second composition, the elastic modulus of the first composition is less than the elastic modulus of the second composition, the specific gravity of the first composition is less than the specific gravity of the second composition, and the Bashore resilience of the first composition is less than the Bashore resilience of the second composition.
17 . The golf ball of claim 1 , wherein the Shore D hardness of the first composition is greater than the Shore D hardness of the second composition, the elastic modulus of the first composition is greater than the elastic modulus of the second composition, the specific gravity of the first composition is greater than the specific gravity of the second composition, and the Bashore resilience of the first composition is greater than the Bashore resilience of the second composition.
18 . The golf ball of claim 1 , wherein the projections cover greater than 50% of the outer surface of the center.
19 . The golf ball of claim 1 , wherein the projections cover greater than 80% of the outer surface of the center.
20 . The golf ball of claim 1 , wherein the projections have a polygonal-shaped base.
21 . The golf ball of claim 1 , wherein the cover comprises an inner cover layer and an outer cover layer, and wherein the outer cover layer is formed from a polyurethane composition.