Multi-layer golf balls with improved interlayer adhesion

Abstract

Casing compositions including carboxyl groups, cover compositions including hydroxyl groups and an adhesion promoter capable of crosslinking carboxyl and hydroxyl groups, and golf balls made from such compositions that have crosslinks between carboxyl groups in the casing composition and hydroxyl groups in the cover composition. The type and concentration of the components in the casing and cover compositions, including the adhesion promoter, affect the adhesion between golf balls having components made from such compositions and, thus, can be used to produce a golf ball having increased durability.

What is claimed is: 
     
         1 . A golf ball, comprising:
 a layer disposed on a core and formed from a first composition comprising carboxyl groups; and   a cover disposed on the casing layer and formed from a second composition comprising an adhesion promoter and hydroxyl groups, wherein the adhesion promoter is bonded to one or more hydroxyl groups in the second composition and one or more carboxyl groups in the first composition to form one or more of the following linkage:   
       
         
           
           
               
               
           
         
         wherein R1 is a first carbon chain in the casing layer and R2 is a second carbon chain in the cover. 
       
     
     
         2 . The golf ball of  claim 1 , wherein the adhesion promoter is included in the cover composition in an amount of about 0.1 percent to about 5.0 percent by weight. 
     
     
         3 . The golf ball of  claim 1 , wherein the adhesion promoter comprises an organic titanate. 
     
     
         4 . The golf ball of  claim 1 , wherein the adhesion promoter comprises an inorganic titanate. 
     
     
         5 . The golf ball of  claim 1 , wherein the first composition comprises an ionomer. 
     
     
         6 . The golf ball of  claim 1 , wherein the second composition comprises a base polymer that is selected from the group consisting of polyurethanes, polyureas, and hybrids, copolymers, and blends thereof. 
     
     
         7 . A golf ball, comprising:
 a subassembly comprising one or more free carboxyl groups;   a cover disposed on the subassembly and formed from a cover composition comprising one or more free hydroxyl groups and an adhesion promoter capable of reacting with the one or more free carboxyl groups and the one or more free hydroxyl groups; and   one or more of the following linkages between the subassembly and cover:   
       
         
           
           
               
               
           
         
         wherein R1 is a first carbon chain in the casing layer and R2 is a second carbon chain in the cover. 
       
     
     
         8 . The golf ball of  claim 7 , wherein the adhesion promoter is included in the cover composition in an amount of about 0.1 percent to about 5.0 percent by weight. 
     
     
         9 . The golf ball of  claim 7 , wherein the adhesion promoter comprises a titanate. 
     
     
         10 . The golf ball of  claim 9 , wherein the titanate is mono reactive. 
     
     
         11 . The golf ball of  claim 9 , wherein the titanate is dual reactive. 
     
     
         12 . The golf ball of  claim 7 , wherein the cover composition comprises a base polymer selected from the group consisting of polyurethanes, polyurethane-polyurea hybrids, polyurethane-polyurea copolymers, and polyurethane-polyurea blends. 
     
     
         13 . A golf ball, comprising:
 a core;   a layer disposed on the core and formed from a first composition comprising one or more carboxyl groups;   a cover disposed on the layer and formed from a second composition comprising titanate and one or more hydroxyl groups; and   one or more of the following crosslinks between the layer and the cover:   
       
         
           
           
               
               
           
         
       
     
     
         14 . The golf ball of  claim 13 , comprising two or more crosslinks between the layer and the cover. 
     
     
         15 . The golf ball of  claim 13 , wherein the titanate is present in the cover composition in a concentration of about 0.1 to about 5.0 percent by weight percent. 
     
     
         16 . The golf ball of  claim 13 , wherein the titanate is organic. 
     
     
         17 . The golf ball of  claim 13 , wherein the titanate is inorganic. 
     
     
         18 . The golf ball of  claim 13 , wherein the titanate is mono reactive. 
     
     
         19 . The golf ball of  claim 13 , wherein the titanate is dual reactive. 
     
     
         20 . The golf ball of  claim 13 , wherein the first composition comprises ionomer and the second composition comprises polyurethane, polyurea, or hybrids, copolymers, and blends thereof.