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 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. A golf ball comprising a core and a cover wherein a portion of the golf ball is formed from a blend comprising:
a linear polybutadiene formed with a neodymium catalyst having a first polydispersity; and
a branched polybutadiene formed with a neodymium catalyst having a second polydispersity greater than the first polydispersity, wherein the second polydispersity is greater than about 2 , wherein the ratio of the weight percentage in the blend of the branched polybutadiene to linear polybutadiene is at least about 60:40.
11. The golf ball of claim 10 , wherein the linear polybutadiene has a first Mooney Stress Relaxation and the branched polybutadiene has a second Mooney Stress Relaxation, and wherein the second Mooney Stress Relaxation is less than the first Mooney Stress Relaxation.
12. The golf ball of claim 10 , wherein the first polydispersity is less than about 3.
13. The golf ball of claim 12 , wherein the linear polybutadiene has a solution viscosity to Mooney Viscosity ratio that is at least 2 times greater than the solution viscosity to Mooney Viscosity ratio of the branched polybutadiene.
14. The golf ball of claim 10 , wherein the core comprises a center and at least one outer core layer, and wherein at least one of the center or the outer core comprises the blend.
15. A golf hall comprising a core and a cover, wherein the core comprises a blend comprising:
a linear polybutadiene formed with a neodymium catalyst having a first polydispersity and a first solution viscosity to Mooney Viscosity ratio; and
a branched polybutadiene formed with a neodymium catalyst having a second polydispersity greater than the first polydispersity and a second solution viscosity to Mooney Viscosity ratio less than the first solution viscosity to Mooney Viscosity ratio, wherein the ratio of the weight percentage in the blend of the branched polybutadiene to linear polybutadiene is at least about 51:49.
16. The golf ball of claim 15 , wherein the cover comprises a thermoset material.
17. The golf ball of claim 16 , further comprising an intermediate layer formed from a thermoplastic material.
18. The golf ball of claim 15 , wherein the second polydispersity is greater than about 2.
19. The golf ball of claim 15 , wherein the second solution viscosity to Mooney Viscosity ratio is about 4 or less and the first solution viscosity to Mooney Viscosity ratio is about 5 or greater.
20. The golf ball of claim 19 , wherein the second solution viscosity to Mooney Viscosity ratio ranges from about 2 to about 4 and the first solution viscosity to Mooney Viscosity ratio ranges from about 5 to about 12.