Blends of linear and branched neodymium-catalyzed rubber formulations for use in golf balls
View Patent ↗The invention relates to golf ball formulations formed from blends of linear and branched polybutadienes catalyzed with neodymium that have improved properties and processing characteristics. Golf ball components may be formed from the blends to provide high coefficient of restitution.
1. A golf ball comprising a core and a cover, wherein the core is formed from a blend comprising:
a linear polybutadiene formed with a neodymium catalyst having a first Mooney viscosity of from about 30 to about 100; and
a branched polybutadiene formed with a neodymium catalyst having a second Mooney viscosity of from about 20 to about 90, wherein the second Mooney viscosity is less than the first Mooney viscosity, wherein the ratio of the weight percent of the branched polybutadiene to linear polybutadiene is at least about 60:40.
2. The golf ball of claim 1 , wherein the linear polybutadiene has a higher Mooney Stress Relaxation than the branched polybutadiene.
3. The golf ball of claim 1 , wherein the linear polybutadiene has a Mooney viscosity of from about 40 to about 80.
4. The golf ball of claim 1 , wherein the branched polybutadiene has a Mooney viscosity of from about 30 to about 75.
5. The golf ball of claim 1 , wherein the branched polybutadiene has a solution viscosity to Mooney Viscosity ratio of about 4 or less.
6. The golf ball of claim 1 , wherein the linear polybutadiene has a solution viscosity to Mooney Viscosity ratio of greater than about 5.
7. The golf ball of claim 1 , wherein the solution viscosity to Mooney Viscosity ratio of the linear polybutadiene is at least about 2 times greater than the solution viscosity to Mooney Viscosity ratio of the branched polybutadiene.
8. The golf ball of claim 1 , wherein the linear polybutadiene has a first polydispersity and the branched polybutadiene has a second polydispersity greater than the first polydispersity.
9. The golf ball of claim 1 , further comprising an intermediate layer disposed between the cover and the core.
10. The golf ball of claim 1 , wherein the blend further comprises cobalt-, lithium-, titanium-, or nickel-catalyzed polybutadienes.
11. A golf ball comprising a core, an intermediate layer, and a cover, wherein the intermediate layer is formed from a blend comprising:
a linear polybutadiene formed with a neodymium catalyst having a first Mooney viscosity of from about 30 to about 100; and
a branched polybutadiene formed with a neodymium catalyst having a second Mooney viscosity of from about 20 to about 90, wherein the second Mooney viscosity is less than the first Mooney viscosity, wherein the ratio of the weight percent of the branched polybutadiene to linear polybutadiene is at least about 60:40.
12. The golf ball of claim 11 , wherein the linear polybutadiene has a Mooney viscosity of from about 40 to about 80.
13. The golf ball of claim 11 , wherein the linear polybutadiene has a higher Mooney Stress Relaxation than the branched polybutadiene.
14. The golf ball of claim 11 , wherein the branched polybutadiene has a solution viscosity to Mooney Viscosity ratio of about 4 or less.
15. The golf ball of claim 11 , wherein the branched polybutadiene has a Mooney viscosity of from about 30 to about 75.
16. The golf ball of claim 11 , wherein the linear polybutadiene has a solution viscosity to Mooney Viscosity ratio of greater than about 5.
17. The golf ball of claim 11 , wherein the solution viscosity to Mooney Viscosity ratio of the linear polybutadiene is at least about 2 times greater than the solution viscosity to Mooney Viscosity ratio of the branched polybutadiene.
18. The golf ball of claim 11 , wherein the linear polybutadiene has a first polydispersity and the branched polybutadiene has a second polydispersity greater than the first polydispersity.
19. The golf ball of claim 11 , wherein the blend further comprises cobalt-, lithium-, titanium-, or nickel-catalyzed polybutadienes.
20. The golf ball of claim 11 , wherein the cover comprises polyurethane, polyurea, or a combination thereof.