Highly-Neutralized Acid Polymer Compositions having a Low Moisture Vapor Transmission Rate and Their Use in Golf Balls

Abstract

The present invention is directed to a golf ball having at least one layer formed from a moisture resistant composition. The moisture resistant composition has a moisture vapor transmission rate of 12.5 g·mil/100 in 2 /day or less and comprises a highly neutralized acid polymer. Golf balls of the present invention include one-piece, two-piece, multi-layer, and wound golf balls. The composition may be present in any one or more of a core layer, a cover layer, or an intermediate layer.

1 . A two-piece golf ball consisting of; 
 a single layer core having a diameter of 1.58 inches or greater, a compression of from 50 to 85, and formed from a moisture resistant composition, wherein the moisture resistant composition has a moisture vapor transmission rate (MVTR) of 12.5 g·mil/100 in 2 /day or less and consists essentially of a highly neutralized acid polymer and optionally one or more additional materials selected from the group consisting of fillers, additives, and melt flow modifiers; and    a polyurethane or polyurea cover having a thickness of 0.05 inches or less.    
   
   
       2 . The golf ball of  claim 1 , wherein the core has a diameter of 1.62 inches and the cover has a thickness of 0.03 inches.  
   
   
       3 . The golf ball of  claim 1 , wherein at least 80% of the acid groups present in the moisture resistant composition are neutralized to salts.  
   
   
       4 . The golf ball of  claim 3 , wherein at least 50% of the acid groups present in the moisture resistant composition are neutralized to salts having counterions selected from the group consisting of Zn, Ca, and combinations thereof.  
   
   
       5 . The golf ball of  claim 1 , wherein at least 70% of the acid groups present in the moisture resistant composition are neutralized to salts having counterions selected from the group consisting of lithium, sodium, potassium, magnesium, calcium, zinc, and combinations thereof.  
   
   
       6 . The golf ball of  claim 1 , wherein the core has a specific gravity of from 1.13.  
   
   
       7 . The golf ball of  claim 1 , wherein the moisture resistant composition has an MVTR of 4.0 g·mil/100 in 2 /day or less.  
   
   
       8 . The golf ball of  claim 3 , wherein the core has a COR of 0.800 or greater and the moisture resistant composition has an MVTR of 2.5 g·mil/100 in 2 /day or less, and wherein 100% of all acid functionalities present in the moisture resistant composition are neutralized.  
   
   
       9 . A multi-layer golf ball consisting of: 
 an inner core layer having a diameter of 1.58 inches or greater, a compression of from 50 to 85, and formed from a moisture resistant composition, wherein the moisture resistant composition has a moisture vapor transmission rate (MVTR) of 12.5 g·mil/100 in 2 /day or less and consists essentially of a highly neutralized acid polymer and optionally one or more additional materials selected from the group consisting of organic acids and salts thereof, fillers, additives, and non-fatty acid melt flow modifiers;    an outer core layer having a thickness of from 0.01 inches to 0.02 inches; and    a polyurethane or polyurea cover having a thickness of 0.04 inches or less.    
   
   
       10 . The golf ball of  claim 9 , wherein the inner core layer has a diameter of 1.62 inches.  
   
   
       11 . The golf ball of  claim 10 , wherein the outer core layer has a thickness of 0.015 inches and the cover has a thickness of 0.015 inches.  
   
   
       12 . The golf ball of  claim 9 , wherein the inner core layer has a specific gravity of 1.13.  
   
   
       13 . The golf ball of  claim 12 , wherein the outer core layer has a specific gravity which is at least 2.5 times the specific gravity of the inner core.  
   
   
       14 . The golf ball of  claim 9 , wherein the moisture resistant composition has an MVTR of 2.5 g·mil/100 in 2 /day or less.  
   
   
       15 . The golf ball of  claim 9 , wherein at least 80% of the acid groups present in the moisture resistant composition are neutralized to salts.  
   
   
       16 . The golf ball of  claim 15 , wherein at least 50% of the acid groups present in the moisture resistant composition are neutralized to salts having counterions selected from the group consisting of Zn, Ca, and combinations thereof.  
   
   
       17 . The golf ball of  claim 11 , wherein the inner core layer has a COR of 0.800 or greater and the moisture resistant composition has an MVTR of 2.5 g·mil/100 in 2 /day or less, and wherein 100% of all acid functionalities present in the moisture resistant composition are neutralized.  
   
   
       18 . A one-piece golf ball having a diameter of from 1.62 inches to 1.74 inches, a compression of from 50 to 85, a COR of 0.800 or greater, and formed from a moisture resistant composition, wherein the moisture resistant composition has a moisture vapor transmission rate (MVTR) of 2.5 g·mil/100 in 2 /day or less and consists essentially of a highly neutralized acid polymer and optionally one or more additional materials selected from the group consisting of fillers, additives, and melt flow modifiers.  
   
   
       19 . The golf ball of  claim 18 , wherein at least 80% of the acid groups present in the moisture resistant composition are neutralized to salts.  
   
   
       20 . The golf ball of  claim 19 , wherein at least 50% of the acid groups present in the moisture resistant composition are neutralized to salts having counterions selected from the group consisting of Zn, Ca, and combinations thereof.