Golf ball

Abstract

A golf ball with reduced driver spin rate is provided. The golf ball comprises a core, an intermediate layer, and a cover. The intermediate layer is formed from a composition having a flexural modulus of at least about 70,000 psi and a melt flow rate of at least about 4 g/10-min. The composition comprises at least one high-acid ionomer. The intermediate layer further has a thickness of less than about 0.025 inches.

What is claimed is:  
     
         1 . A golf ball, comprising: 
 a core;    a cover; and    an intermediate layer, disposed between the core and the cover, formed from a composition comprising at least one high-acid ionomer and having a material hardness;    wherein the intermediate layer has an on-ball hardness less than the material hardness by at least about 5 Shore D.    
     
     
         2 . The golf ball of  claim 1 , wherein the on-ball hardness is less than the material hardness by at least about 10 Shore D.  
     
     
         3 . The golf ball of  claim 1 , wherein the material hardness is at least about 65 Shore D.  
     
     
         4 . The golf ball of  claim 3 , wherein the material hardness is at least about 70 Shore D.  
     
     
         5 . The golf ball of  claim 1 , wherein the on-ball hardness of the intermediate layer is less than about 65 Shore D.  
     
     
         6 . The golf ball of  claim 5 , wherein the on-ball hardness ranges from about 45 Shore D to about 60 Shore D.  
     
     
         7 . The golf ball of  claim 1 , wherein the composition has a melt flow rate of at least about 4 g/10-min.  
     
     
         8 . The golf ball of  claim 1 , wherein the composition further comprises a modulus-enhancing filler such that the composition with the filler has a flexural modulus substantially greater than without the filler.  
     
     
         9 . The golf ball of  claim 1 , wherein the composition has a flexural modulus of at least about 70,000 psi.  
     
     
         10 . The golf ball of  claim 1 , wherein the high-acid ionomer comprises at least about 16% by weight of a carboxylic acid.  
     
     
         11 . The golf ball of  claim 1 , wherein the high-acid ionomer has a melt flow rate of at least about 4 g/10-min.  
     
     
         12 . The golf ball of  claim 1 , wherein the composition further comprises at least one high-flow material having a melt flow rate of greater than about 4 g/10-min.  
     
     
         13 . The golf ball of  claim 12 , wherein the high-flow material comprises thermoplastic elastomers, high-flow ionomers, non-ionomeric olefin/acid copolymers or terpolymers, partially or fully neutralized polymers, polyamides, polyolefins, polyurethanes, polyureas, epoxies, polyesters, polyetheresters, polyetheramides, polyamides, metallocene-catalyzed polymers, functionalized styrene-butadiene elastomers, styrenic block copolymers, acrylonitrile-butadiene-styrene copolymers, silicone, or metal salts of fatty acids.  
     
     
         14 . The golf ball of  claim 1 , wherein the at least one high-acid ionomer is present in the composition in an amount of greater than about 30% by weight.  
     
     
         15 . A golf ball, comprising: 
 a core;    a cover; and    an intermediate layer having a thickness of less than about 0.025 inches, disposed between the core and the cover, formed from a composition comprising at least one high-acid ionomer and having a material hardness;    wherein the intermediate layer has an on-ball hardness substantially less than the material hardness.    
     
     
         16 . The golf ball of  claim 15 , wherein the thickness of the intermediate layer is from about 0.005 inches to about 0.02 inches.  
     
     
         17 . The golf ball of  claim 15 , wherein the composition has a flexural modulus of at least about 70,000 psi and a melt flow rate of at least about 4 g/10-min.  
     
     
         18 . A golf ball, comprising: 
 a core;    a cover; and    an intermediate layer, disposed between the core and the cover, formed from a composition comprising a blend of a high-acid ionomer having a carboxylic acid content of at least about 16% by weight and a thermoplastic elastomer, and having a material hardness;    wherein the intermediate layer has an on-ball hardness substantially less than the material hardness.    
     
     
         19 . The golf ball of  claim 18 , wherein the thermoplastic elastomer is ionomeric or non-ionomeric.  
     
     
         20 . The golf ball of  claim 18 , wherein the composition further comprises a modulus-enhancing filler such that the composition with the filler has a flexural modulus substantially greater than without the filler.