Golf ball having a thermosetting intermediate and outer cover and a thermoplastic inner cover

Abstract

A golf ball includes a core and a three-layer cover disposed about the core. The cover includes a thermoplastic inner cover layer having a hardness of about 66 to 90 Shore C; an outer cover layer formed from a polyurethane, a polyurea, or a hybrid thereof, and an intermediate cover layer disposed between the inner and outer cover layers. The outer cover layer has a hardness of about 52 to 85 Shore C. The intermediate cover layer has a hardness of about 74 to 100 Shore C and greater than the inner cover layer hardness and the outer cover layer hardness. The thermoplastic inner cover comprises a highly-neutralized ionomer comprising a copolymer of ethylene and an α,β-unsaturated carboxylic acid, an organic acid or salt thereof, and sufficient cation source to neutralize the acid groups of the copolymer by about 100%.

What is claimed is: 
     
         1 . A golf ball comprising:
 a core; and   a cover disposed adjacent the core, the cover comprising:
 a thermoplastic inner cover layer disposed about the core and having a hardness of about 66 Shore C to about 90 Shore C; 
 an outer cover layer comprising a polyurethane, a polyurea, or a urethane-urea hybrid, the outer cover layer having a hardness of about 52 Shore C to about 85 Shore C; and 
 an intermediate cover layer disposed between the inner and outer cover layers, the intermediate cover layer having a hardness of about 74 Shore C to about 100 Shore C and being greater than the inner cover layer hardness and the outer cover layer hardness; 
   wherein the thermoplastic inner cover comprises a highly-neutralized ionomer comprising a copolymer of ethylene and an α,β-unsaturated carboxylic acid, an organic acid or salt thereof, and sufficient cation source to neutralize the acid groups of the copolymer by 80% or greater.   
     
     
         2 . The golf ball of  claim 1 , wherein the intermediate layer hardness is greater than the inner cover layer hardness and greater than the outer cover layer hardness by at least 5 Shore C. 
     
     
         3 . The golf ball of  claim 2 , wherein the intermediate layer hardness is greater than the inner cover layer hardness and greater than the outer cover layer hardness by at least 10 Shore C. 
     
     
         4 . The golf ball of  claim 1 , wherein the polyurethane, polyurea, or urethane-urea blend is a castable thermoset or reaction injection moldable thermoset. 
     
     
         5 . The golf ball of  claim 1 , wherein the core comprises a center and at least one outer core layer. 
     
     
         6 . The golf ball of  claim 1 , wherein the center is a single solid layer formed from a homogeneous composition. 
     
     
         7 . The golf ball of  claim 1 , wherein the intermediate cover layer comprises a thermoset polyurethane, a thermoset polyurea, or a hybrid thereof. 
     
     
         8 . The golf ball of  claim 1 , wherein the acid groups of the copolymer are neutralized by 90% or greater. 
     
     
         9 . The golf ball of  claim 1 , wherein the organic acid or salt thereof comprises barium, lithium, sodium, zinc, bismuth, chromium, cobalt, copper, potassium, strontium, titanium, tungsten, magnesium, cesium, iron, nickel, silver, aluminum, tin, or calcium salts, or salts of fatty acids. 
     
     
         10 . The golf ball of  claim 9 , wherein the fatty acid salt comprises stearic acid, behenic acid, erucic acid, oleic acid, linoelic acid or dimerized derivatives thereof. 
     
     
         11 . The golf ball of  claim 9 , wherein the organic acid or salt thereof comprises a magnesium salt of oleic acid. 
     
     
         12 . The golf ball of  claim 1 , wherein the acid copolymer further comprises a softening comonomer. 
     
     
         13 . The golf ball of  claim 1 , wherein the highly-neutralized ionomer further comprises a second polymer component. 
     
     
         14 . The golf ball of  claim 13 , wherein the second polymer component comprises ionomeric copolymers and terpolymers, ionomer precursors, thermoplastics, polyamides, polycarbonates, polyesters, polyurethanes, polyureas, thermoplastic elastomers, polybutadiene rubber, balata, grafted- or non-grafted metallocene-catalyzed polymers, single-site polymers, high-crystalline acid polymers, or cationic ionomers. 
     
     
         15 . The golf ball of  claim 1 , wherein the outer cover comprises a thermoplastic polyurethane and the intermediate cover layer comprises a polyurea formed from the reaction product of a prepolymer comprising an isocyanate and an amine-terminated PTMEG and an amine-terminated curing agent. 
     
     
         16 . The golf ball of  claim 1 , wherein the thermoplastic inner cover layer further comprises polyolefins, metallocenes, polyesters, polyamides, thermoplastic elastomers, copolyether-amides, copolyether-esters, or mixtures thereof. 
     
     
         17 . The golf ball of  claim 1 , wherein the outer cover layer hardness is less than the inner cover layer hardness. 
     
     
         18 . A golf ball comprising:
 a core; and   a cover disposed adjacent the core, the cover comprising:
 an inner cover layer disposed about the core and having a hardness of about 66 Shore C to 90 Shore C, the inner cover layer comprising a highly-neutralized ionomer comprising a copolymer of ethylene and an α,β-unsaturated carboxylic acid, an organic acid or salt thereof, and sufficient cation source to neutralize the acid groups of the copolymer by about 100%; 
 a castable thermoset outer cover layer having a hardness of about 52 Shore C and 85 Shore C; and 
 a non-ionomeric thermosetting intermediate cover layer disposed between the inner and outer cover layers and having a hardness of about 74 Shore C to 100 Shore C and being greater than the inner cover layer and the outer cover layer; 
   wherein the inner cover layer has a first thickness, the outer cover layer has a second thickness, and the intermediate cover layer has a third thickness less than the first or second thickness by at least 20%.   
     
     
         19 . A golf ball comprising:
 a core; and   a cover disposed adjacent the core, the cover comprising:
 an inner cover layer disposed about the core and having a hardness of about 66 Shore C to 90 Shore C, the inner cover layer comprising a highly-neutralized ionomer comprising a copolymer of ethylene and an α,β-unsaturated carboxylic acid, an organic acid or salt thereof, and sufficient cation source to neutralize the acid groups of the copolymer by about 100%; 
 a castable thermoset polyurethane outer cover layer having a hardness of about 52 Shore C and 85 Shore C; and 
 a non-ionomeric thermosetting polyurethane polyurea intermediate cover layer disposed between the inner and outer cover layers and having a hardness greater than the inner cover layer and the outer cover layer; 
   wherein the inner cover layer has a first thickness, the outer cover layer has a second thickness, and the intermediate cover layer has a hardness of about 74 Shore C to 100 Shore C, and a third thickness less than the first or second thickness by at least 20%.