Golf ball incorporating at least one layer formed from a millable polyurethane rubber composition
Golf ball comprising at least one layer having a Shore D material hardness of from about 10 to about 55 and consisting of a millable polyurethane rubber composition comprising rubber consisting of: at least one polyether-based millable polyurethane rubber; at least one polyester-based millable polyurethane rubber; at least one polycaprolactone-based millable polyurethane rubber; or combinations thereof; wherein the millable polyurethane rubber composition is vulcanized. The rubber may be mixed/compounded with additional non-rubber ingredients such as at least one cross linking agent, peroxide initiator, filler, antioxidant, processing agent, light stabilizer, colorant, adhesion promotor, isocyanate and/or polyol, or combinations thereof. The at least one layer may be a cover layer, with a second layer, formed from at least one of a thermoset urethane or a thermoplastic material, being adjacent to an inner surface of the cover layer and meanwhile disposed about a polybutadiene-containing core. The rubber may be peroxide and/or sulfur cured.
1. A golf ball comprising at least one layer having a Shore C hardness of greater than 75 and consisting of a millable polyurethane rubber composition comprising a mixture of: (i) at least one millable urethane rubber consisting of: at least one polyether-based polyurethane rubber; at least one polyester-based polyurethane rubber; at least one polycaprolactone-based millable polyurethane rubber; or combinations thereof; (ii) at least one peroxide initiator; and (iii) N, N-m-Phenylenedimaleimide in an amount of at least about 25 parts per 100 parts of the millable urethane rubber;
wherein the millable polyurethane rubber composition is vulcanized; and
wherein the golf ball has CoR of at least about 0.700.
2. The golf ball of claim 1 , wherein the at least one layer is a cover layer.
3. The golf ball of claim 2 , wherein the rubber is a polyether-based polyurethane rubber.
4. The golf ball of claim 1 , wherein the mixture further comprises at least one antioxidant, processing agent, light stabilizer, colorant, adhesion promotor, cross linking agent, filler, or combinations thereof.
5. The golf ball of claim 1 , further comprising a second layer that is formed from at least one of a thermoset urethane or a thermoplastic material and is adjacent to an inner surface of the cover layer.
6. The golf ball of claim 5 , wherein the thermoplastic material consists of a partially or fully neutralized ionomer composition.
7. The golf ball of claim 5 , wherein the second layer is an inner cover layer.
8. The golf ball of claim 7 , wherein the inner cover layer surrounds a core.
9. The golf ball of claim 7 , wherein the inner cover layer surrounds a third layer that is disposed about a polybutadiene-containing core.
10. The golf ball of claim 5 , wherein the second layer is an outer core layer disposed about an inner core layer comprising polybutadiene.
11. The golf ball of claim 1 , having a compression of from about 30 to about 110.
12. The golf ball of claim 11 , having a CoR of from about 0.700 to about 0.820.
13. The golf ball of claim 1 , wherein the amount of N, N-m-Phenylenedimaleimide is from about 25 to about 37 parts per 100 parts of the millable urethane rubber.
14. The golf ball of claim 1 , wherein the Shore C hardness is at least about 83.
15. A method of making a golf ball, comprising the steps of:
providing a subassembly comprising at least one layer;
forming a cover layer about the subassembly;
wherein at least one of the at least one layer and the cover layer has a Shore C hardness of greater than 75 and consists of a millable polyurethane rubber composition comprising a mixture of: (i) at least one millable urethane rubber consisting of: at least one polyether-based polyurethane rubber; at least one polyester-based polyurethane rubber; at least one polycaprolactone-based millable polyurethane rubber; or combinations thereof; (ii) at least one peroxide initiator; and (iii) N, N-m-Phenylenedimaleimide in an amount of at least about 25 parts per 100 parts of the millable urethane rubber; and
wherein the millable polyurethane rubber composition is exposed to a vulcanizing agent; and
wherein the golf ball has CoR of at least about 0.700.
16. The method of claim 15 , wherein the at least one layer is a cover layer.
17. The method of claim 16 , wherein the rubber consists of at least one polyether-based polyurethane rubber.
18. The method of claim 15 , wherein the mixture further comprises at least one ingredient selected from cross linking agents; antioxidants; processing agents; light stabilizers; colorants; or adhesion promotors; isocyanates, polyols; fillers; or combinations thereof.
19. The method of claim 18 , wherein the rubber is compounded with the at least one ingredient.
20. The method of claim 15 , further comprising forming an outermost layer of the subassembly adjacent an inner surface of the cover layer wherein the outermost layer is formed from at least one of a thermoset urethane or a thermoplastic material.
21. The method of claim 20 , wherein the thermoplastic material consists of a partially or fully neutralized ionomer composition.
22. The method of claim 15 , wherein the amount of N, N-m-Phenylenedimaleimide is from about 25 to about 37 parts per 100 parts of the millable urethane rubber.
23. The method of claim 15 , wherein the Shore C hardness is at least about 83.