Multi-layer golf ball having a cover layer with increased moisture resistance

Abstract

A golf ball having a core, a harder non-ionomer inner layer, and a cover layer. The inner layer having a material hardness of 50 Shore D to 80 Shore D, a flexural modulus of 30 to 175 kpsi, and comprising a composition that comprises a polyester elastomer. The cover layer is formed from a composition having multiple reactive and/or non-reactive ingredients, and having a material hardness of 25 Shore D to 70 Shore D and a flexural modulus of 2,000 psi to 100,000 psi. The cast cover includes a composition that comprises a hydrogenated telechelic polyhydrocarbon polyahl having a number average molecular weight of 1,500 to 10,000. The cover is a cast urethane or urea material.

1 . A golf ball, comprising: 
 a core having a diameter of less than 1.65 inches, a compression of 100 or less, and a coefficient of restitution of greater than 0.77;    a non-ionomer intermediate layer disposed about the core, the intermediate layer having a material hardness of 50 Shore D to 80 Shore D and a flexural modulus of 30 to 175 kpsi; and    a cover layer disposed about the intermediate layer, the cover layer having a material hardness of 25 Shore D to 70 Shore D and a flexural modulus of 2,000 psi to 100,000 psi and comprising a composition that comprises a hydrogenated telechelic polyhydrocarbon polyahl having a number average molecular weight of 1,500 to 10,000.    
   
   
       2 . The golf ball of  claim 1 , wherein the intermediate layer comprises a composition that comprises a polyester elastomer.  
   
   
       3 . The golf ball of  claim 1 , wherein the cover layer comprises a cast urethane material.  
   
   
       4 . The golf ball of  claim 1 , wherein the cover layer comprises a cast urea material.  
   
   
       5 . The golf ball of  claim 1 , wherein the hardness of the cover is at least 5 Shore D points lower than the inner layer.  
   
   
       6 . The golf ball of  claim 1 , wherein the golf ball further has a dimple pattern having 250 to 450 dimples.  
   
   
       7 . The golf ball of  claim 1 , wherein the core further has a specific gravity of 1.4 g/cm 3  or less.  
   
   
       8 . The golf ball of  claim 1 , wherein the core comprises a rubber having a Mooney viscosity of 30 or greater, a cross-linking agent at a level of 15 phr or more by weight of the rubber, a regrind and/or filler, and optionally a compound that enhances the coefficient of restitution.  
   
   
       9 . The golf ball of  claim 1 , wherein the composition of the cover layer forms a thermoplastic polyurethane, a thermoset polyurethane, a thermoplastic polyurea, or a thermoset polyurea.  
   
   
       10 . The golf ball of  claim 1 , wherein the cover layer has a water vapor permeability of 0.1 g·mm/(m 2 ·day·mm Hg) or less.  
   
   
       11 . The golf ball of  claim 1 , wherein the golf ball displays a low weight gain, when subjected to total water submersion at ambient temperature for 3 weeks, of 0.003 oz/wk or less.  
   
   
       12 . The golf ball of  claim 1 , wherein the golf ball further includes at least one outer core layer disposed about the inner core.