Golf ball compositions

Abstract

Disclosed herein are hard and flexible compositions, i.e., compositions which have a flexural modulus that is less than the value that is expected based on the composition's hardness. The compositions preferably have a hardness/modulus relationship represented by the formula H ≧11.889 Ln( M )+47, where H is the hardness of the composition, in JIS-C, and M is the flexural modulus of the composition, in ksi; or a softness/stiffness relationship represented by the formula if M <110, then H ≧8.5218 Ln( M )+32.5 if M ≧110, then H ≧72.5, where H is the hardness of the composition, in Shore D, and M is the flexural modulus of the composition, in ksi.

1 . A golf ball comprising:
 a core having an outer surface and a geometric center and being formed from a substantially homogeneous formulation; and   a cover layer;   wherein the difference between the Shore C hardness of the outer surface of the core and the Shore C hardness of the center of the core is 8 or less;   and wherein the cover layer is formed from a polymer blend composition having a JIS-C hardness (H) and a flexural modulus in ksi (M) wherein H≧11.889 Ln(M)+47.   
     
     
         2 . The golf ball of  claim 1 , wherein H≧11.889 Ln(M)+48. 
     
     
         3 . The golf ball of  claim 1 , wherein H≧11.889 Ln(M)+49. 
     
     
         4 . A golf ball comprising:
 an inner core layer having an outer surface and a geometric center and being formed from a first substantially homogeneous formulation;   an outer core layer having an outer surface and an inner surface and being formed from a second substantially homogeneous formulation; and   a cover layer;   wherein the difference between the Shore C hardness of the outer surface of the inner core layer and the Shore C hardness of the center of the inner core layer is 8 or less;   and wherein the cover layer is formed from a polymer blend composition having a JIS-C hardness (H) and a flexural modulus in ksi (M) wherein H≧11.889 Ln(M)+47.   
     
     
         5 . The golf ball of  claim 4 , wherein the difference between the Shore C hardness of the outer surface of the outer core layer and the Shore C hardness of the inner surface of the outer core layer is 8 or less. 
     
     
         6 . The golf ball of  claim 4 , wherein H≧11.889 Ln(M)+48. 
     
     
         7 . The golf ball of  claim 4 , wherein H≧11.889 Ln(M)+49. 
     
     
         8 . A golf ball comprising:
 a core having an outer surface and a geometric center and being formed from a substantially homogeneous formulation;   an intermediate layer; and   a cover layer;   wherein the difference between the Shore C hardness of the outer surface of the core and the Shore C hardness of the center of the core is 8 or less;   and wherein the intermediate layer is formed from a polymer blend composition having a JIS-C hardness (H) and a flexural modulus in ksi (M) wherein H≧11.889 Ln(M)+47.   
     
     
         9 . The golf ball of  claim 8 , wherein H≧11.889 Ln(M)+48. 
     
     
         10 . The golf ball of  claim 8 , wherein H≧11.889 Ln(M)+49. 
     
     
         11 . A golf ball comprising:
 an inner core layer having an outer surface and a geometric center and being formed from a first substantially homogeneous formulation;   an outer core layer having an outer surface and an inner surface and being formed from a second substantially homogeneous formulation;   an intermediate layer; and   a cover layer;   wherein the difference between the Shore C hardness of the outer surface of the inner core layer and the Shore C hardness of the center of the inner core layer is 8 or less;   and wherein the intermediate layer is formed from a polymer blend composition having a JIS-C hardness (H) and a flexural modulus in ksi (M) wherein H≧11.889 Ln(M)+47.   
     
     
         12 . The golf ball of  claim 11 , wherein the difference between the Shore C hardness of the outer surface of the outer core layer and the Shore C hardness of the inner surface of the outer core layer is 8 or less. 
     
     
         13 . The golf ball of  claim 8 , wherein H≧11.889 Ln(M)+48. 
     
     
         14 . The golf ball of  claim 8 , wherein H≧11.889 Ln(M)+49.