Thin-layer-covered golf ball with improved velocity
View Patent ↗A golf ball comprising a center comprising a polybutadiene having a molecular weight of greater than 200,000 and a resilience index of at least about 40; and a cover layer comprising a polyurethane composition formed from a prepolymer having no greater than 7.5 percent by weight unreacted isocyanate groups.
1. A golf ball comprising:
a center comprising a resilient polymer comprising:
a rubber material having a molecular weight of greater than about 200,000, wherein the rubber material has a resilience index of at least about 40, and wherein the resilience index of the rubber material is calculated using the formula:
Resilience Index=100,000*[(Tan δ at 10 cpm)−(Tan δ at 1000 cpm)]/990;
a crosslinking material present in an amount of about 10 to about 40 parts per hundred of the resilient polymer;
a free radical source present in an amount of about 0.1 to about 15 parts per hundred of the resilient polymer;
a cis-to-trans catalyst present in an amount of about 0.1 to about 10 parts per hundred of the resilient polymer, wherein the cis-to-trans catalyst comprises a metal organosulfur compound; and
a cover comprising a thermoplastic or thermoset polyurethane.
2. The golf ball of claim 1 , wherein the resilience index is greater than about 50.
3. The golf ball of claim 1 , wherein the rubber material comprises polybutadiene.
4. The golf ball of claim 2 , wherein the molecular weight of the polybutadiene is from about 300,000 to about 500,000.
5. The golf ball of claim 2 , wherein the polybutadiene comprises less than about 7 percent vinyl isomer.
6. The golf ball of claim 5 , wherein the polybutadiene comprises less than about 4 percent vinyl isomer.
7. The golf ball of claim 1 , wherein the center has an outer diameter of about 1.55 inches or greater.
8. The golf ball of claim 1 , wherein the cover has a thickness of about 0.05 inches or less.
9. The golf ball of claim 1 , further comprising an intermediate layer disposed between the center and the cover.
10. The golf ball of claim 9 , wherein the intermediate layer has an outer diameter of about 1.58 inches or greater.
11. A golf ball comprising:
a center comprising a resilient polymer, wherein the resilient polymer comprises:
polybutadiene having a molecular weight of about 300,000 to about 500,000 and a resilience index of about 40, wherein the resilience index is calculated using the formula:
Resilience Index=100,000*[(Tan δ at 10 cpm)−(Tan δ at 1000 cpm)]/990;
a crosslinking material present in an amount of about 10 to about 40 parts per hundred of the resilient polymer;
a free radical source present in an amount of about 0.1 to about 15 parts per hundred of the resilient polymer;
a cis-to-trans catalyst present in an amount of about 0.1 to about 10 parts per hundred of the resilient polymer; and
a cover formed of a castable reactive liquid material.
12. The golf ball of claim 11 , wherein the cis-to-trans catalyst comprises an organosulfur compound, an aromatic organic compound, or a combination thereof.
13. The golf ball of claim 12 , wherein the aromatic organic compound comprises a hydroxy group, a metal salt of a hydroxyl, or a combination thereof.
14. The golf ball of claim 12 , wherein the aromatic organic compound comprises a mercapto group, a metal salt of a mercapto group, or a combination thereof.
15. The golf ball of claim 12 , wherein the organosulfur compound comprises metal.
16. The golf ball of claim 12 , wherein the organosulfur compound is substantially free of metal.
17. A golf ball comprising:
a center comprising a resilient polymer, wherein the resilient polymer comprises:
a rubber material having a molecular weight of greater than about 200,000 and a resilience index of about 50, wherein the resilience index is calculated using the equation:
Resilience Index=100,000*[(Tan δ at 10 cpm)−(Tan δ at 1000 cpm)]/990;
a crosslinking material present in an amount of about 10 to about 40 parts per hundred of the resilient polymer;
a free radical source present in an amount of about 0.1 to about 15 parts per hundred of the resilient polymer;
a cis-to-trans catalyst present in an amount sufficient to produce a resilient polymer comprising about 32 percent or greater trans-isomer; and
a cover formed of a thermoset or thermoplastic polyurethane, wherein the cover has a hardness of about 30 Shore D to about 60 Shore D.
18. The golf ball of claim 17 , wherein the rubber material comprises polybutadiene.
19. The golf ball of claim 17 , wherein the polybutadiene comprises less than about 4 percent vinyl-isomer.
20. The golf ball of claim 17 , wherein the resilient polymer comprises less than about 7 percent vinyl-isomer.
21. The golf ball of claim 11 , wherein the cis-to-trans is present in an amount sufficient to produce a resilient polymer comprising about 32 percent or greater trans-isomer.