Golf balls having multi-layer cores based on polyalkenamer compositions
View Patent ↗The present invention generally relates to golf balls and more particularly to golf balls having multi-layered cores comprising a thermoset rubber center, a thermoplastic intermediate core layer, and a thermoset rubber outer core layer. A cover layer is disposed about the multi-layered core. At least one of the center, intermediate core layer, and outer core layer comprises a polyalkenamer rubber. The rubber composition helps improve resiliency of the core and provides the ball with a comfortable and soft feel.
1. A golf ball comprising:
an inner core layer having an outer surface and geometric center, the inner core being formed from a first thermoset rubber composition and having a diameter of from 1.000 inches to 1.580 inches, wherein the outer surface hardness is 50 Shore C to 85 Shore C and the center hardness is 40 Shore C to 65 Shore C;
an intermediate core layer formed from a thermoplastic composition and having a thickness of 0.005 inches to 0.100 inches and a surface hardness of 50 Shore D to 90 Shore D;
an outer core layer formed from a second thermoset rubber composition and having a thickness of 0.010 inches to 0.100 inches and an outer surface hardness that is greater than the Shore C outer surface hardness of the inner core layer; and
a cover layer having a thickness of from 0.010 inches to 0.050 inches and a surface hardness of 60 Shore C or greater;
wherein at least one of the center, intermediate core layer, and outer core layer comprises a polyalkenamer rubber composition, the polyalkenamer being present in the composition in an amount of at least 50 weight percent.
2. The golf ball of claim 1 , wherein the specific gravity of at least one of the center, intermediate core layer, and outer core layer is less than 1.05 g/cc.
3. The golf ball of claim 1 , wherein the center has a specific gravity of greater than 1.25 g/cc.
4. The golf ball of claim 1 , wherein the compression of the inner core layer is 80 or less.
5. The golf ball of claim 4 , wherein the compression of the inner core layer is 50 or less.
6. The golf ball of claim 1 , wherein the intermediate core layer has a surface hardness of 60 Shore D or less.
7. The golf ball of claim 1 , wherein the intermediate core layer has a surface hardness of 60 Shore D or greater.
8. The golf ball of claim 1 , wherein the outer core layer has a thickness of 0.035 inches to 0.075 inches.
9. The golf ball of claim 1 , wherein the outer core layer has an outer surface hardness of 70 Shore C or greater.
10. The golf ball of claim 9 , wherein the outer core layer has an outer surface hardness of 90 Shore C or greater.
11. The golf ball of claim 1 , wherein the cover layer comprises an inner cover layer and an outer cover layer.
12. The golf ball of claim 11 , wherein the inner cover layer has a material hardness greater than the material hardness of the outer cover layer.
13. A golf ball comprising:
an inner core layer having an outer surface and geometric center, the inner core being formed from a first thermoset rubber composition and having a diameter of from 1.000 inches to 1.580 inches, wherein the outer surface hardness is 50 Shore C to 95 Shore C and the center hardness is 40 Shore C to 75 Shore C;
an intermediate core layer formed from a thermoplastic composition and having a thickness of 0.005 inches to 0.100 inches and a surface hardness of 50 Shore D to 90 Shore D;
an outer core layer formed from a second thermoset rubber composition and having a thickness of 0.010 inches to 0.100 inches and an outer surface hardness that is less than the Shore C outer surface hardness of the inner core layer; and
a cover layer having a thickness of from 0.010 inches to 0.050 inches and a surface hardness of 60 Shore C or greater;
wherein at least one of the center, intermediate core layer, and outer core layer comprises a polyalkenamer rubber composition, the polyalkenamer being present in the composition in an amount of at least 50 weight percent.
14. The golf ball of claim 13 , wherein the specific gravity of at least one of the center, intermediate core layer, and outer core layer is less than 1.05 g/cc.
15. The golf ball of claim 13 , wherein the center has a specific gravity of greater than 1.25 g/cc.
16. The golf ball of claim 13 , wherein the outer core layer has an outer surface hardness of 90 Shore C or less.
17. The golf ball of claim 13 , wherein the outer core layer has an outer surface hardness of 85 Shore C or less.
18. The golf ball of claim 13 , wherein the outer core layer has a thickness of 0.035 inches to 0.075 inches.
19. The golf ball of claim 13 , wherein the cover layer comprises an inner cover layer and an outer cover layer.
20. The golf ball of claim 13 , wherein the inner cover layer has a material hardness greater than the material hardness of the outer cover layer.