Dual core golf balls having reduced driver spin

Abstract

Dual component cores having positive hardness and compression gradients and golf balls including these cores are disclosed. The hardness, compression, and diameter relationships in the core assemblage components help to reduce the spin rate of the ball off the driver while still providing desirable performance characteristics in and around the green.

What is claimed is: 
     
         1 . A golf ball, comprising:
 a core assemblage comprising:
 a center having a geometric center hardness H 1  and a surface hardness H 2  and a SCDI compression C 1 , wherein H 1  is about 50 percent to about 85 percent of H 2 ; and 
 an outer core layer disposed about the inner core layer and having a surface hardness H 3 , wherein H 3  is about 70 percent to about 98 percent of H 2 , and wherein the core assemblage has a SCDI compression C 2  and C 1  is about 50 percent to about 80 percent of C 2 ; 
   a layer disposed about the core assemblage; and   a cover layer disposed about the layer.   
     
     
         2 . The golf ball of  claim 1 , wherein the center comprises a first rubber formulation comprising a first amount of co-agent and the outer core layer comprises a second rubber formulation comprising a second amount of co-agent. 
     
     
         3 . The golf ball of  claim 2 , wherein the first amount of co-agent is about 50 to about 80 percent of the second amount of co-agent. 
     
     
         4 . The golf ball of  claim 2 , wherein each of the first and second rubber formulations comprise polybutadiene rubber, butyl rubber, or a blend thereof. 
     
     
         5 . The golf ball of  claim 1 , wherein the cover layer has a thickness in the range of about 0.010 to about 0.080 inches. 
     
     
         6 . The golf ball of  claim 1 , wherein the cover layer comprises a material selected from the group consisting of polyurethanes, polyureas, and hybrids, copolymers, and blends thereof. 
     
     
         7 . The golf ball of  claim 1 , wherein the layer comprises an ionomer material. 
     
     
         8 . The golf ball of  claim 1 , wherein H 1  is in the range of about 50 to about 60 Shore C, H 2  is in the range of about 70 to about 90 Shore C, and H 3  is in the range of about 80 to about 100 Shore C to provide a positive hardness gradient from the center to the outer core layer. 
     
     
         9 . The golf ball of  claim 1 , wherein C 1  is about 60 percent to about 75 percent of C 2 . 
     
     
         10 . A golf ball, comprising:
 a core assemblage comprising:
 a center having a geometric center hardness H 1 , a surface hardness H 2 , a diameter D 1 , and a SCDI compression C 1 ; and 
 an outer core layer disposed about the center and having a surface hardness H 3 , a diameter D 2 , wherein the core assemblage has a SCDI compression C 2 , and wherein 
   
       
         
           
             
               
                 0.35 
                 ≤ 
                 
                   
                     
                       H 
                       1 
                     
                     
                       H 
                       3 
                     
                   
                   
                     
                       C 
                       2 
                     
                     
                       C 
                       1 
                     
                   
                 
                 ≤ 
                 0.55 
               
               ; 
             
           
         
         a layer disposed about the core assemblage to form an intermediate ball; and 
         a cover layer disposed about the intermediate ball. 
       
     
     
         11 . The golf ball of  claim 10 , wherein H 1  is in the range of about 50 to about 60 Shore C, H 2  is in the range of about 70 to about 90 Shore C, and H 3  is in the range of about 80 to about 100 Shore C to provide a positive hardness gradient from the center to the outer core layer. 
     
     
         12 . The golf ball of  claim 10 , wherein 
       
         
           
             
               0.35 
               ≤ 
               
                 
                   
                     H 
                     2 
                   
                   
                     H 
                     3 
                   
                 
                 
                   
                     C 
                     2 
                   
                   
                     C 
                     1 
                   
                 
               
               ≤ 
               
                 0.7 
                 
                   5 
                   . 
                 
               
             
           
         
       
     
     
         13 . The golf ball of  claim 10 , wherein the center comprises a first rubber formulation comprising a first amount of co-agent and the outer core layer comprises a second rubber formulation comprising a second amount of co-agent. 
     
     
         14 . The golf ball of  claim 13 , wherein the first amount of co-agent is about 60 to about 80 percent of the second amount of co-agent. 
     
     
         15 . The golf ball of  claim 10 , wherein C 1  is about 60 percent to about 75 percent of C 2 . 
     
     
         16 . The golf ball of  claim 10 , wherein D 1  is about 70 percent to 90 percent of D 2 . 
     
     
         17 . A golf ball, comprising:
 a core assemblage comprising:
 a center having a geometric center hardness H 1 , a surface hardness H 1  and a SCDI compression C 1 ; and 
 an outer core layer disposed about the center and having a surface hardness H 3 , wherein H 1  is in the range of about 60 to about 80 Shore C, H 2  is in the range of about 70 to about 90 Shore C, and H 3  is in the range of about 80 to about 100 Shore C to provide a positive hardness gradient from the center to the outer core layer, wherein the core assemblage has a SCDI compression C 2 , and wherein the C 1  is about 60 percent to about 75 percent of C 2 ; 
   an intermediate layer disposed about the core assemblage to form an intermediate ball; and   a cover layer disposed about the intermediate ball.   
     
     
         18 . The golf ball of  claim 17 , wherein the cover layer comprises a material selected from the group consisting of polyurethanes, polyureas, and hybrids, copolymers, and blends thereof. 
     
     
         19 . The golf ball of  claim 17 , wherein the intermediate layer comprises an ionomer material. 
     
     
         20 . The golf ball of  claim 17 , wherein C 1  is about 60 percent to about 70 percent of C 2 .