GOLF BALL COMPOSITIONS
Disclosed herein are soft and stiff compositions, i.e., compositions which have a flexural modulus that is greater 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 )+42, 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 <56, then H ≦8.5218 Ln( M )+26.5 if M ≧56, then H ≦8.5218 Ln( M )+28.5, where H is the hardness of the composition, in Shore D, and M is the flexural modulus of the composition, in ksi. The compositions preferably comprise an ionomer having an acid content of 9 wt % or less and a high level of fatty acid.
1 . A golf ball comprising at least one layer formed from a thermoplastic composition, the thermoplastic composition comprising:
(a) an E/X- or E/X/Y-type copolymer or metal salt thereof, wherein E is ethylene, X is an α,β-unsaturated carboxylic acid present in an amount of 9 wt % or less, based on the total weight of the copolymer, and Y is an acrylate selected from alkyl acrylates and aryl acrylates present in an amount of from 0 wt % to 50 wt %, based on the total weight of the copolymer;
(b) a fatty acid or metal salt thereof present in an amount of 20 wt % or greater, based on the total weight of the thermoplastic composition; and
(c) optionally an additional cation source;
wherein at least 50% of the acid groups present in the thermoplastic composition are neutralized; and
wherein the thermoplastic composition has a JIS-C hardness (H) and a flexural modulus in ksi (M) wherein H≦11.889 Ln(M)+42, and wherein M>6 ksi.
2 . The golf ball of claim 1 , wherein H≦9.45 Ln(−0.0105M 2 +3.95M−14)+40.
3 . The golf ball of claim 1 , wherein H≦87 JIS-C.
4 . The golf ball of claim 1 , wherein X is present in an amount of 7 wt % or less, based on the total weight of the copolymer or metal salt thereof.
5 . The golf ball of claim 1 , wherein X is present in an amount of 6 wt % or less, based on the total weight of the copolymer or metal salt thereof.
6 . The golf ball of claim 1 , wherein the fatty acid or metal salt thereof is present in an amount of 30 wt % or greater, based on the total weight of the thermoplastic composition.
7 . The golf ball of claim 1 , wherein the fatty acid or metal salt thereof is present in an amount of 35 wt % or greater, based on the total weight of the thermoplastic composition.
8 . The golf ball of claim 1 , wherein 70% or greater of the acid groups present in the thermoplastic composition are neutralized.
9 . The golf ball of claim 1 , wherein 90% or greater of the acid groups present in the thermoplastic composition are neutralized.
10 . The golf ball of claim 1 , wherein 100% of the acid groups present in the thermoplastic composition are neutralized.
11 . A golf ball comprising at least one layer formed from a thermoplastic composition, the thermoplastic composition comprising:
(a) an E/X- or E/X/Y-type copolymer or metal salt thereof, wherein E is ethylene, X is an α,β-unsaturated carboxylic acid present in an amount of less than 9 wt %, based on the total weight of the copolymer, and Y is an acrylate selected from alkyl acrylates and aryl acrylates present in an amount of from 0 wt % to 50 wt %, based on the total weight of the copolymer;
(b) a fatty acid or metal salt thereof present in an amount of 35 wt % or greater, based on the total weight of the thermoplastic composition; and
(c) optionally an additional cation source;
wherein at least 50% of the acid groups present in the thermoplastic composition are neutralized; and
wherein the thermoplastic composition has a JIS-C hardness (H) and a flexural modulus in ksi (M) wherein H≦11.889 Ln(M)+42, and wherein M>6 ksi.
12 . The golf ball of claim 11 , wherein H≦9.45 Ln(−0.0105M 2 +3.95M−14)+40.
13 . The golf ball of claim 11 , wherein H≦87 JIS-C.
14 . The golf ball of claim 11 , wherein 70% or greater of the acid groups present in the thermoplastic composition are neutralized.
15 . The golf ball of claim 11 , wherein 90% or greater of the acid groups present in the they composition are neutralized.
16 . The golf ball of claim 11 , wherein 100% of the acid groups present in the thermoplastic composition are neutralized.
17 . A golf ball comprising at least one layer formed from a thermoplastic composition, the thermoplastic composition comprising:
(a) an E/X- or E/X/Y-type copolymer or metal salt thereof, wherein E is ethylene, X is an α,β-unsaturated carboxylic acid present in an amount of 7 wt % or less, based on the total weight of the copolymer, and Y is an acrylate selected from alkyl acrylates and aryl acrylates present in an amount of from 0 wt % to 50 wt %, based on the total weight of the copolymer;
(b) a fatty acid or metal salt thereof present in an amount of 35 wt % or greater, based on the total weight of the thermoplastic composition; and
(c) optionally an additional cation source;
wherein at least 70% of the acid groups present in thermoplastic composition are neutralized; and
wherein the thermoplastic composition has a JIS-C hardness (H) and a flexural modulus in ksi (M) wherein H≦11.889 Ln(M)+42, and wherein M>6 ksi.
18 . The golf ball of claim 17 , wherein H≦9.45 Ln(−0.0105M 2 +3.95M−14)+40.
19 . The golf ball of claim 17 , wherein H≦87 JIS-C.
20 . The golf ball of claim 17 , wherein 100% of the acid groups present in the thermoplastic composition are neutralized.