Golf Balls Comprising Highly-Neutralized Acid Polymers

Abstract

A golf ball comprising a core formed from an unvulcanized rubber material cured to a hardness of 50 Shore A to 60 Shore D and having a diameter of 0.5 inches to 1.55 inches; a thermoplastic or thermoset cover layer having a shore D hardness of 55 or less and comprising polyurethane, polyurea, or a copolymer comprising urethane and urea segments; and an intermediate layer disposed between the core and the cover layer, the intermediate layer including a polymer comprising a copolymer of ethylene and an α,β-unsaturated carboxylic acid, the acid being 100% neutralized by a salt of an organic acid, a cation source, or a suitable base of the organic acid; wherein the cover layer has a thickness of 0.02 inches to 0.06 inches.

1 . A golf ball comprising: 
 a core formed from an unvulcanized rubber material cured to a hardness of 50 Shore A to 60 Shore D and having a diameter of 0.5 inches to 1.55 inches;    a thermoplastic or thermoset cover layer having a shore D hardness of 55 or less and comprising polyurethane, polyurea, or a copolymer comprising urethane and urea segments; and    an intermediate layer disposed between the core and the cover layer, the intermediate layer including a polymer comprising a copolymer of ethylene and an α,β-unsaturated carboxylic acid, the acid being 100% neutralized by a salt of an organic acid, a cation source, or a suitable base of the organic acid;    wherein the cover layer has a thickness of 0.02 inches to 0.06 inches.    
   
   
       2 . The golf ball of  claim 1 , wherein the cation source is selected from a group consisting of metal cations of lithium, sodium, potassium, magnesium, calcium, barium, lead, tin, zinc, or aluminum.  
   
   
       3 . The golf ball of  claim 2 , wherein the cation source is a blend of sodium and calcium cations or a blend of zinc and calcium cations.  
   
   
       4 . The golf ball of  claim 1 , wherein the salt of an organic acid comprises an organic acid selected from the group consisting of aliphatic organic acids, aromatic organic acids, saturated mono- or multi-functional organic acids, unsaturated mono- or multi-functional organic acids, and multi-unsaturated mono- or multi-functional organic acids.  
   
   
       5 . The golf ball of  claim 1 , wherein the salt of an organic acid comprises stearic acid, behenic acid, erucic acid, oleic acid, linoelic acid or dimerized derivatives thereof.  
   
   
       6 . The golf ball of  claim 1 , wherein the salt of an organic acid comprises a cation selected from the group consisting of barium, lithium, sodium, zinc bismuth, chromium, cobalt, copper, potassium, strontium, titanium, tungsten, magnesium, cesium, iron, nickel, silver, aluminum, tin, and calcium.  
   
   
       7 . The golf ball of  claim 1 , wherein the core further comprises ionomeric copolymers and terpolymers, ionomer precursors, thermoplastics, thermoplastic elastomers, grafted metallocene-catalyzed polymers, non-grafted metallocene-catalyzed polymers, single-site polymers, high-crystalline acid polymers and their ionomers, cationic ionomers, and mixtures thereof.  
   
   
       8 . The golf ball of  claim 1 , wherein the unvulcanized rubber material has a Mooney viscosity of 45 to 65.  
   
   
       9 . The golf ball of  claim 8 , wherein the unvulcanized rubber material has a Mooney viscosity of 45 to 55.  
   
   
       10 . The golf ball of  claim 1 , wherein the cover layer is injection molded, cast, reaction injection molded, or compression molded over the core.  
   
   
       11 . The golf ball of  claim 1 , wherein the cover layer has material hardness of 65 Shore D or less.  
   
   
       12 . The golf ball of  claim 11 , wherein the cover layer material hardness is 60 Shore D or less.  
   
   
       13 . The golf ball of  claim 1 , wherein the core has a resilience index of 40 or greater.  
   
   
       14 . The golf ball of  claim 13 , wherein the core has a resilience index of 50 or greater,  
   
   
       15 . The golf ball of  claim 1 , wherein the intermediate layer has a material hardness between 40 Shore D and 70 Shore D.  
   
   
       16 . The golf ball of  claim 1 , wherein the cover layer has a material hardness of 40 Shore D or less.  
   
   
       17 . The golf ball of  claim 1 , wherein the intermediate layer has a first hardness and the cover layer has a second hardness, and a ratio of the first hardness to the second hardness is 1.5 or greater.  
   
   
       18 . The golf ball of  claim 1 , wherein the cover layer comprises an inner cover layer and an outer cover layer.  
   
   
       19 . The golf ball of  claim 1 , wherein the core comprises a center and at least one outer core layer.  
   
   
       20 . The golf ball of  claim 1 , wherein the inner cover layer has material hardness of at least about 60 Shore D and the outer cover layer has a material hardness of no greater than about 60 Shore D.