Multilayer golf ball

Abstract

A golf ball comprising a solid core, an outer cover layer, and a casing disposed between the core and the outer cover layer, wherein the core has an outer diameter of no greater than about 1.58 inches; the casing has an outer diameter of greater than 1.58 inches and a material hardness of between about 30 and about 70 Shore D; and the outer cover layer has a material hardness of less than about 45 Shore D.

What is claimed is:  
     
         1 . A golf ball comprising a solid core, an outer cover layer, and a casing disposed between the core and the outer cover layer, wherein: 
 the core has an outer diameter of no greater than about 1.58 inches;    the casing has an outer diameter of greater than 1.58 inches and a material hardness of between about 30 and about 70 Shore D; and    the outer cover layer has a material hardness of less than about 45 Shore D.    
     
     
         2 . The golf ball of  claim 1 , wherein the outer cover layer material hardness is less than about 40 Shore D.  
     
     
         3 . The golf ball of  claim 2 , wherein the outer cover layer material hardness is between about 25 and about 40 Shore D.  
     
     
         4 . The golf ball of  claim 1 , wherein the casing material hardness is between about 50 and about 65 Shore D.  
     
     
         5 . The golf ball of  claim 1 , wherein at least one of the casing and the outer cover layer has a thickness of less than about 0.05 inches.  
     
     
         6 . The golf ball of  claim 5 , wherein at least one of the casing and the outer cover layer has a thickness of between about 0.02 inches and about 0.04 inches.  
     
     
         7 . The golf ball of  claim 1 , wherein the casing outer diameter is from 1.58 inches to about 1.64 inches.  
     
     
         8 . The golf ball of  claim 7 , wherein the casing outer diameter is from about 1.59 inches to about 1.63 inches.  
     
     
         9 . The golf ball of  claim 1 , wherein the outer cover layer is formed of a polyurethane composition comprising the reaction product of at least one polyisocyanate, a polyol, and at least one curing agent.  
     
     
         10 . The golf ball of  claim 1 , wherein the ball has a moment of inertia of less than about 85 g.cm 2 .  
     
     
         11 . The golf ball of  claim 10 , wherein the ball has a moment of inertia of less than about 83 g.cm 2 .  
     
     
         12 . The golf ball of  claim 1 , wherein the core has a first hardness and the casing has a second hardness greater than the first.  
     
     
         13 . The golf ball of  claim 12 , wherein the outer cover layer has a third hardness less than the second hardness.  
     
     
         14 . The golf ball of  claim 1 , wherein the casing comprises ionic copolymers of ethylene and an unsaturated monocarboxylic acid; vinyl resins; polyolefins; polyurethanes; polyureas; polyamides; thermoplastic and thermoset resins; metallocenes; acrylic resins; thermoplastic polyesters; and mixtures thereof.  
     
     
         15 . The golf ball of  claim 14 , wherein the casing comprises comprises ionic copolymers of ethylene and an unsaturated monocarboxylic acid.  
     
     
         16 . The golf ball of  claim 1 , wherein the casing material hardness is between about 40 and about 70 Shore D and the outer cover layer material hardness is less than about 40 Shore D.  
     
     
         17 . The golf ball of  claim 1 , wherein a ratio of the casing material hardness to the outer cover layer material hardness is greater than 1.5.  
     
     
         18 . The golf ball of  claim 1 , wherein the core comprises a cis-to-trans catalyst.  
     
     
         19 . The golf ball of  claim 1 , wherein at least one of the core, casing, and cover layer are cast, reaction injection molded, liquid injection molded, injection molded, or a mixture thereof.