Golf ball intermediate layer

Abstract

A golf ball intermediate layer consists essentially of a specified triblock copolymer or its hydrogenation product, a specified block copolymer, or mixtures of these. The layer unexpectedly provides for improved ball performance with respect to spin rate, feel, and durability, without the expected disadvantages of use of such a layer. The layer can be incorporated into a wide variety of known ball constructions.

We claim:  
     
         1 . A golf ball intermediate layer consisting essentially of: 
 one or more triblock copolymers;    one or more hydrogenation products of the triblock copolymers;    one or more hydrogenated diene block copolymers;    or mixtures thereof;    wherein each triblock copolymer has 
 (i) a first polymer block comprising an aromatic vinyl compound,  
 (ii) a second polymer block comprising a conjugated diene compound, and  
 (iii) a hydroxyl group located at a block copolymer,  
   wherein each hydrogenated diene block copolymer has a polystyrene-reduced number-average molecular weight of from 50,000 to 600,000 and is a hydrogenation product of 
 (i) an A-B block copolymer, in which A is an alkenyl aromatic compound polymer block, and B is either 
 (1) a conjugated diene homopolymer block, wherein the vinyl content of the conjugated diene portion is more than 60%, or  
 (2) an alkenyl aromatic compound-conjugated diene random copolymer block wherein the vinyl content of the conjugated diene portion is 15-60%, or  
 
 (ii) an A-B-C block copolymer, in which A and B are as defined above and C is an alkenyl aromatic compound-conjugated diene copolymer tapered block, wherein the proportion of the alkenyl aromatic compound increases gradually, or  
 (iii) an A-B-A block copolymer, in which A and B are as defined above,  
   wherein in each of the hydrogenated diene block copolymers, 
 the weight proportion of the alkenyl aromatic compound to conjugated diene is from 5/95 to 60/40,  
 the content of the bound alkenyl aromatic compound in at least one block A is at least 3% by weight,  
 the total of the bound alkenyl aromatic compound contents in the two block A's or the block A and the block C is 5% to 25% by weight based on the total monomers, and  
 at least 80% of the double bond unsaturations of the conjugated diene portion is saturated by the hydrogenation.  
   
     
     
         2 . A golf ball intermediate layer as defined in  claim 1 , wherein the aromatic vinyl compound is selected from the group consisting of styrene, methylstyrene, 4-propylstyrene, 1,3-dimethylstyrene, vinylnaphthalene, and vinlyanthracene.  
     
     
         3 . A golf ball intermediate layer as defined in  claim 1 , wherein the conjugated diene compound is selected from the group consisting of 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and 1,3-hexadiene.  
     
     
         4 . A golf ball intermediate layer as defined in  claim 1 , wherein each of the one or more triblock copolymers has a number average molecular weight between about 30,000 and about 1,000,000.  
     
     
         5 . A golf ball intermediate layer as defined in  claim 1 , wherein the ratio by weight of the triblock copolymers to the hydrogenated diene block copolymers ranges between 99:1 and 1:99.  
     
     
         6 . A golf ball intermediate layer as defined in  claim 1 , further comprising fillers, stabilizers, colorants, processing aids, antioxidants, or mixtures thereof.  
     
     
         7 . A golf ball intermediate layer as defined in  claim 6 , wherein the fillers have specific gravity of greater than about 2.  
     
     
         8 . A golf ball comprising a core, a cover, and an intermediate layer as defined in  claim 1  situated between the core and the cover.  
     
     
         9 . A golf ball as defined in  claim 8 , wherein the core comprises an inner core and one or more outer cores encasing the inner core.  
     
     
         10 . A golf ball as defined in  claim 8 , wherein the core comprises liquid.  
     
     
         11 . A golf ball as defined in  claim 8 , further comprising one or more layers situated between the core and the cover.  
     
     
         12 . A golf ball as defined in  claim 8 , further comprising a layer of rubber thread situated between the core and the cover.  
     
     
         13 . A golf ball as defined in  claim 8 , wherein the cover comprises copolymeric ionomer, terpolymeric ionomer, or mixtures thereof.  
     
     
         14 . A golf ball as defined in  claim 8 , wherein the cover comprises elastomeric material.  
     
     
         15 . A golf ball intermediate layer as defined in  claim 1 , wherein the intermediate layer has a thickness between about 0.005 in. and about 0.1 in.  
     
     
         16 . A golf ball intermediate layer as defined in  claim 15 , wherein the intermediate layer has a thickness between about 0.01 in. and about 0.05 in.  
     
     
         17 . A golf ball intermediate layer as defined in  claim 16 , wherein the intermediate layer has a thickness between about 0.02 in. and about 0.05 in.  
     
     
         18 . A golf ball intermediate layer as defined in  claim 1 , wherein the intermediate layer is prepared using injection molding.  
     
     
         19 . A golf ball intermediate layer as defined in  claim 1 , wherein the intermediate layer is prepared using compression molding.  
     
     
         20 . A golf ball intermediate layer as defined in  claim 1 , wherein the intermediate layer is prepared by depositing a powder material over a golf ball portion.  
     
     
         21 . A golf ball intermediate layer consisting essentially of a triblock copolymer, the triblock copolymer having 
 (a) a first polymer block comprising styrene or α-methylstyrene,    (b) a second polymer block comprising isoprene or 1,3-butadiene, and    (c) a hydroxyl group located at a block copolymer, or a hydrogenation product of the triblock copolymer, or mixtures thereof.    
     
     
         22 . A golf ball intermediate layer as defined in  claim 21 , wherein the intermediate layer has a thickness of about 0.1 in.  
     
     
         23 . A golf ball intermediate layer consisting essentially of one or more hydrogenated diene block copolymers, wherein each hydrogenated diene block copolymer has a polystyrene-reduced number-average molecular weight of from 50,000 to 600,000 and is a hydrogenation product of 
 (i) an A-B block copolymer, in which A is an alkenyl aromatic compound polymer block, and B is either 
 (1) a conjugated diene homopolymer block, wherein the vinyl content of the conjugated diene portion is more than 60%, or  
 (2) an alkenyl aromatic compound-conjugated diene random copolymer block wherein the vinyl content of the conjugated diene portion is 15-60%, or  
   (ii) an A-B-C block copolymer, in which A and B are as defined above and C is an alkenyl aromatic compound-conjugated diene copolymer tapered block, wherein the proportion of the alkenyl aromatic compound increases gradually, or    (iii) an A-B-A block copolymer, in which A and B are as defined above,     wherein in each of the hydrogenated diene block copolymers,    the weight proportion of the alkenyl aromatic compound to conjugated diene is from 5/95 to 60/40,    the content of the bound alkenyl aromatic compound in at least one block A is at least 3% by weight,    the total of the bound alkenyl aromatic compound contents in the two block A's or the block A and the block C is 5% to 25% by weight based on the total monomers, and    at least 80% of the double bond unsaturations of the conjugated diene portion is saturated by the hydrogenation.