Multi-layer golf balls having moisture barrier layers based on polyalkenamer compositions

Abstract

Golf balls having a dual-core comprising an inner core and outer moisture barrier core layer are provided. The outer core help prevent moisture from penetrating into the inner core. A cover layer, preferably made of a polyurethane or polyurea material, is disposed about the outer core layer. The inner and outer cores are formed of a rubber composition, preferably a polyalkenamer rubber. The polyalkenamer rubber composition may further include other rubbers such as polybutadiene, polyisoprene, ethylene propylene rubber, ethylene propylene diene rubber, and styrene-butadiene rubber. The outer core has a moisture vapor transmission rate (MVTR) lower than that of the cover. In one version, the outer core has a MVTR of 1 grams·mm/m 2 ·day or less, preferably in the range of 0.45 to 0.95 grams·mm/m 2 ·day.

1 . A golf ball, comprising:
 a dual-core comprising an inner core and outer moisture barrier core layer, wherein the outer core layer surrounds the inner core, the inner core having a diameter of about 1.30 inches to about 1.58 inches and a compression of about 100 or less, the inner core being formed from a first rubber composition and the outer core layer being formed from a second rubber composition, the second rubber composition comprising a polyalkenamer in an amount of at least 50 weight percent; the outer core layer having a thickness of about 0.01 inches to about 0.20 inches and outer surface hardness of about 80 Shore C or greater, wherein the outer core has a moisture vapor transmission rate lower than that of the cover; and   a cover layer surrounding the outer core layer, the cover layer having a material hardness of about 30 to about 65 Shore D.   
     
     
         2 . The golf ball of  claim 1 , wherein the outer core has a moisture vapor transmission rate of 1 grams·mm/m 2 ·day or less. 
     
     
         3 . The golf ball of  claim 2 , wherein the outer core has a moisture vapor transmission rate of 0.45 to 0.95 grams·mm/m 2 ·day. 
     
     
         4 . The golf ball of  claim 1 , wherein the inner core has a compression of 70 to 90. 
     
     
         5 . The golf ball of  claim 1 , wherein the inner core has a surface hardness of 75 to 90 Shore C. 
     
     
         6 . The golf ball of  claim 1 , wherein the inner core has a surface hardness of 78 to 87 Shore C. 
     
     
         7 . The golf ball of  claim 1 , wherein the outer core layer has a surface hardness of 83 to 97 Shore C. 
     
     
         8 . The golf ball of  claim 1 , wherein the outer core layer has a surface hardness of 85 to 93 Shore C. 
     
     
         9 . The golf ball of  claim 1 , wherein the inner core has as diameter of 1.45 to 1.57 inches. 
     
     
         10 . The golf ball of  claim 1 , wherein the outer core layer has a thickness of 0.025 to 0.060 inches. 
     
     
         11 . The golf ball of  claim 1 , wherein the cover layer comprises an inner cover layer and outer cover layer. 
     
     
         12 . The golf ball of  claim 11 , wherein the inner cover has a material hardness greater than the material hardness of the outer cover. 
     
     
         13 . A golf ball, comprising:
 a dual-core comprising an inner core and outer moisture barrier core layer, wherein the outer core layer surrounds the inner core, the inner core having a diameter of about 1.51 inches to about 1.58 inches and a compression of about 100 or less, the inner core being formed from a first rubber composition and the outer core layer being formed from a second rubber composition, the second rubber composition comprising a polyalkenamer in an amount of at least 50 weight percent; the outer core layer having a thickness of about 0.01 inches to about 0.06 inches and outer surface hardness of about 80 Shore C or greater, wherein the outer core has a moisture vapor transmission rate lower than that of the cover; and   a cover layer surrounding the outer core layer, the cover layer being formed from a composition comprising polyurethane; polyurea; or a hybrid, copolymer or blend of polyurethane and polyurea and having a material hardness of about 30 to about 65 Shore D.   
     
     
         14 . The golf ball of  claim 13 , wherein the outer core has a moisture vapor transmission rate of 1 grams·mm/m 2 ·day or less. 
     
     
         15 . The golf ball of  claim 14 , wherein the outer core has a moisture vapor transmission rate of 0.45 to 0.95 grams·mm/m 2 ·day. 
     
     
         16 . The golf ball of  claim 13 , wherein the cover layer has a thickness of 0.010 to 0.055 inches. 
     
     
         17 . The golf ball of  claim 13 , wherein the cover layer has a thickness of 0.020 to 0.040 inches. 
     
     
         18 . The golf ball of  claim 13 , wherein the cover layer has a material hardness of 40 to 63 Shore D. 
     
     
         19 . The golf ball of  claim 13 , wherein the cover layer comprises an inner cover layer and outer cover layer, the inner cover layer being formed from an olefin-based ionomer copolymer and the outer cover layer being formed from a composition comprising polyurethane; polyurea; or a hybrid, copolymer, or blend of polyurethane and polyurea. 
     
     
         20 . The golf ball of  claim 19 , wherein the inner cover has a material hardness of 60 Shore D or greater and the outer cover has a material hardness of 30 to 65 Shore D.