Golf ball core hardness gradient manipulation using hardness agent and water releasing agent
Compositions including a hardness agent and a water releasing agent and golf ball cores made from such compositions having a tailored hardness gradient are disclosed. The type and concentration of the components in the composition, including a hardness agent and a water releasing agent, affect the hardness, hardness gradient, and compression of cores made from the composition and, thus, can be used to produce a golf ball having desirable performance characteristics.
1. A golf ball, comprising:
a rubber layer comprising:
a rubber formulation comprising a base rubber, a hardening agent, and a water releasing agent, wherein the hardening agent comprises a benzoic compound having a first functional group that is a nitro functional group and a second functional group that is an amino functional group; and
a cover layer disposed about the rubber layer.
2. The golf ball of claim 1 , wherein the hardening agent is present in an amount of about 0.05 and about 1.0 parts per hundred rubber.
3. The golf ball of claim 1 , wherein the hardening agent comprises an isomer of nitroaniline.
4. The golf ball of claim 1 , wherein the water releasing agent is a metal salt hydrate.
5. The golf ball of claim 1 , wherein the water releasing agent is present in an amount of about 0.5 and about 5.0 parts per hundred rubber.
6. The golf ball of claim 1 , wherein the rubber layer further comprises a geometric center having a hardness H C , a geometric surface having a hardness H S , and a hardness gradient H Gr equal to the difference in the H C and H S , wherein H Gr is between 2 Shore C and 42 Shore C.
7. The golf ball of claim 6 , wherein H C is in the range of about 50 Shore C to about 85 Shore C, H S is in the range of about 65 Shore C to about 95 Shore C, and H S is greater than H C .
8. The golf ball of claim 1 , wherein the base rubber is polybutadiene rubber, ethylene-propylene-diene rubber, or a blend thereof.
9. A golf ball, comprising:
a rubber layer comprising:
a rubber formulation comprising a base rubber, a hardening agent, and a water releasing agent, wherein the hardening agent comprises a benzoic compound having a first functional group that is a nitro functional group and a second functional group that is a sulfhydryl functional group; and
a cover layer disposed about the rubber layer.
10. The golf ball of claim 9 , wherein the hardening agent is present in an amount of about 0.05 and about 1.0 parts per hundred rubber.
11. The golf ball of claim 9 , wherein the hardening agent comprises an isomer of nitrothiophenol.
12. The golf ball of claim 9 , wherein the water releasing agent is a metal salt hydrate.
13. The golf ball of claim 9 , wherein the water releasing agent is present in an amount of about 0.5 and about 5.0 parts per hundred rubber.
14. The golf ball of claim 9 , wherein the rubber layer further comprises a geometric center having a hardness H C , a geometric surface having a hardness H S , and a hardness gradient H Gr equal to the difference in the H C and H S , wherein H Gr is between 2 Shore C and 42 Shore C.
15. The golf ball of claim 14 , wherein H C is in the range of about 50 Shore C to about 85 Shore C, H S is in the range of about 65 Shore C to about 95 Shore C, and H S is greater than H C .
16. A golf ball, comprising:
a rubber layer comprising:
a rubber formulation comprising a base rubber, a hardening agent, and a water releasing agent, wherein the hardening agent comprises a benzoic compound having a first functional group that is a nitro functional group and a second functional group that is selected from the group consisting of hydroxyl, amino, and sulfhydryl functional groups; and
a cover layer disposed about the rubber layer.
17. The golf ball of claim 16 , wherein the hardening agent is present in an amount of about 0.05 and about 1.0 parts per hundred rubber.
18. The golf ball of claim 16 , wherein the hardening agent comprises nitrophenol, nitroaniline, nitrothiophenol, or a combination thereof.
19. The golf ball of claim 16 , wherein the second functional group is a hydroxyl functional group.
20. The golf ball of claim 16 , wherein the rubber layer further comprises a geometric center having a hardness H C , a geometric surface having a hardness H S , and a hardness gradient H Gr equal to the difference in the H C and H S , wherein H Gr is between 2 Shore C and 42 Shore C.