Golf Balls Including Dense High Acid Ionomers

Abstract

Golf balls having one or more structural components that include a highly neutralized acid polymer with a high acid content and a uniformly increased density. The core of the golf ball may be made up of the highly neutralized acid polymer. The highly neutralized acid polymer may have desired hardness and flexural modulus values. The highly neutralized acid polymer enables the golf ball to provide consistent play characteristics.

What is claimed is: 
     
         1 . A golf ball comprising a core and a cover layer surrounding the core, wherein at least one of the core and the cover layer comprises a highly neutralized polymer having an acid content of at least about 20% and a density of from about 1.00 to about 1.10 g/cm 3 . 
     
     
         2 . The golf ball according to  claim 1 , wherein the highly neutralized acid polymer has an acid content of at least about 30%. 
     
     
         3 . The golf ball according to  claim 1 , wherein the highly neutralized acid polymer is neutralized with a magnesium cation. 
     
     
         4 . The golf ball according to  claim 1 , wherein the highly neutralized acid polymer is neutralized with magnesium acetate. 
     
     
         5 . A golf ball according to  claim 1 , wherein a flat cross-section of the at least one of the core and the cover layer comprising the highly neutralized acid polymer has a hardness that varies by less than about 5 Shore D between any two points. 
     
     
         6 . The golf ball according to  claim 5 , wherein the highly neutralized acid polymer has a flexural modulus of at least about 75,000 psi. 
     
     
         7 . The golf ball according to  claim 5 , wherein the highly neutralized acid polymer has a Shore D material hardness of at least about 65. 
     
     
         8 . The golf ball according to  claim 5 , wherein the core of the golf ball comprises the highly neutralized acid polymer. 
     
     
         9 . The golf ball according to  claim 8 , wherein the core of the golf ball comprises less than about 1% by weight of density-adjusting fillers. 
     
     
         10 . The golf ball according to  claim 8 , wherein the core has a hardness that varies by less than about 3 Shore D between any two points on the flat hemispherical cross section of the core. 
     
     
         11 . The golf ball according to  claim 5 , wherein the core has a hardness that varies by less than about 1 Shore D between any two points on the flat hemispherical cross section of the core. 
     
     
         12 . The golf ball according to  claim 5 , wherein the golf ball exhibits a predetermined play characteristic selected from the group consisting of: initial velocity, initial spin, and total distance in response to being hit by a golf club under a predetermined shot characteristic selected from the group consisting of: swing speed, angle of attack, and face angle, wherein the play characteristic varies in value by less than about 1% for each 1% by which the shot characteristic varies in value. 
     
     
         13 . A golf ball according to  claim 1 , wherein the highly neutralized acid polymer is neutralized to substantially 99% with a magnesium cation and wherein the core has a surface Shore D hardness of at least about 50, a cross-sectional hardness that varies by less than about 3 Shore D between any two points, a flexural modulus of at least about 50,000 psi, and comprises less than about 0.5% by weight of density-adjusting fillers. 
     
     
         14 . The golf ball of  claim 13 , wherein the core consists essentially of the highly neutralized acid polymer. 
     
     
         15 . The golf ball of  claim 13 , wherein the core comprises an inner core that comprises the highly neutralized acid polymer and an outer core surrounding the inner core and the cover comprises an inner cover layer and an outer cover layer surrounding the inner cover layer.