Golf ball comprising a core having a shallow hardness gradient
View Patent ↗A golf ball comprising: a core having an outer surface and a geometric center and being formed from a substantially homogenous rubber composition comprising a carbon-carbon initiator, wherein the outer surface has a hardness that differs from a hardness at the geometric center by up to about 10 Shore C; optionally an intermediate layer disposed about the core; and a cover layer disposed about the core (or intermediate layer where present).
1. A golf ball comprising:
a core having an outer surface and a geometric center and being formed from a substantially homogenous rubber composition comprising a carbon-carbon initiator;
an intermediate layer disposed about the core; and
a cover layer disposed about the intermediate layer;
wherein the outer surface has a hardness that differs from a hardness at the geometric center by up to about 5 Shore C.
2. The golf ball of claim 1 , wherein the hardness of the outer surface differs from the hardness at the geometric center by less than about 3 Shore C.
3. The golf ball of claim 1 , wherein the hardness of the outer surface is substantially the same as the hardness at the geometric center.
4. The golf ball of claim 1 , wherein the geometric center has a hardness of from about 55 Shore C to about 82 Shore C.
5. The golf ball of claim 1 , wherein the rubber composition comprises the carbon-carbon initiator in an amount of from about 0.2 phr to about 2.0 phr.
6. The golf ball of claim 1 , the core being molded for about 8 min. to about 16 min. at a cure temperature of greater than 330° F.
7. The golf ball of claim 1 , wherein the rubber composition comprises an antioxidant in a ratio of antioxidant to active initiator used in said rubber composition of about 0.4 or greater.
8. The golf ball of claim 1 , wherein the core has a compression of from about 40 atti to about 100 atti.
9. The golf ball of claim 1 , wherein the core has a diameter of from about 1.30 inches to about 1.620 inches.
10. A golf ball comprising:
a core having an outer surface and a geometric center and being formed from a substantially homogenous composition comprising a carbon-carbon initiator;
an intermediate layer disposed about the core and comprising an ionomeric material; and
a cover layer disposed about the intermediate layer, the cover comprising a castable polyurea or a castable polyurethane;
wherein the outer surface has a hardness that differs from a hardness at the geometric center by up to about 5 Shore C.
11. The golf ball of claim 10 , wherein the hardness of the outer surface is substantially the same as the hardness at the geometric center.
12. The golf ball of claim 10 , wherein the hardness of the outer surface differs from the hardness at the geometric center by less than about 5 Shore C.
13. The golf ball of claim 10 , wherein the substantially homogenous composition comprises the carbon-carbon initiator in an amount of from about 0.2 phr to about 2.0 phr.
14. The golf ball of claim 10 , the core being molded for from about 8 min. to about 16 min. at a cure temperature of greater than 330° F.
15. The golf ball of claim 10 , wherein the rubber composition comprises an antioxidant in a ratio of antioxidant to active initiator used in said rubber composition of about 0.4 or greater.
16. The golf ball of claim 10 , wherein the core has a compression of from about 40 atti to about 100 atti.
17. The golf ball of claim 10 , wherein the core has a diameter of about 1.30 inches to about 1.620 inches.
18. A golf ball comprising:
a core being formed from a substantially homogenous thermoset rubber composition comprising a carbon-carbon initiator, said core having an outer surface and a geometric center;
a cover layer disposed about the core, said cover layer comprising an ionomer or a highly-neutralized ionomer;
wherein the outer surface has a hardness that differs from a hardness at the geometric center by up to about 5 Shore C.
19. The golf ball of claim 18 , wherein the substantially homogenous thermoset rubber composition comprises the carbon-carbon initiator in an amount of from about 0.2 phr to about 2.0 phr.
20. The golf ball of claim 18 , wherein the rubber composition comprises an antioxidant in a ratio of antioxidant to active initiator of about 0.4 or greater.
21. The golf ball of claim 18 , wherein the geometric center has a hardness of from about 55 Shore C to about 82 Shore C.
22. The golf ball of claim 18 , the core being molded for about 8 min. to about 16 min. at a cure temperature of greater than 330° F.
23. The golf ball of claim 18 , wherein the core has a compression of from about 40 atti to about 100 atti.
24. The golf ball of claim 18 , wherein the core has a diameter of from about 1.30 inches to about 1.620 inches.