Methods for making polyurea polymer and products prepared therefrom

1. A method of forming a golf ball comprising a core of at least one layer and cover of at least one layer, the cover being formed from a polyurea composition, the composition being prepared by a reaction comprising the steps of:

i) forming an amine-terminated first prepolymer by reacting isocyanate compound A with a stoichiometric excess of polyamine compound;

ii) forming an isocyanate-terminated second prepolymer by reacting the first prepolymer with a stoichiometric excess of isocyanate compound B; and

iii) reacting the second prepolymer with an amine-terminated chain extender, wherein isocyanate compound A is 4,4′-diisocyanatodicyclohexylmethane diisocyanate (H 12 MDI) and isocyanate compound B is 1,6-hexamethylene diisocyanate (HDI) oligomer.

2. A method of forming a golf ball comprising a core of at least one layer and cover of at least one layer, the cover being formed from a polyurea composition, the composition being prepared by a reaction comprising the steps of:

i) forming an amine-terminated first prepolymer by reacting isocyanate compound A with a stoichiometric excess of polyamine compound;

ii) forming an isocyanate-terminated second prepolymer by reacting the first prepolymer with a stoichiometric excess of isocyanate compound B; and

iii) reacting the second prepolymer with an amine-terminated chain extender, wherein isocyanate compound A is 2,4-toluene diisocyanate (TDI) and isocyanate compound B is 4,4′-diphenylmethane diisocyanate (MDI).

3. The method of claim 1 , wherein the polyamine compound is selected from the group consisting of amine-terminated hydrocarbons, polyethers, polyesters, polycarbonates, polycaprolactones, and mixtures thereof.

4. The method of claim 1 , wherein the polyamine compound is an amine-terminated copolymer of polytetramethylene oxide and propylene oxide.

5. The method of claim 1 , wherein the chain extender is an amine-terminated chain extender selected from the group consisting of 4,4′-diamino-diphenylmethane; 3,5-diethyl-(2,4- or 2,6-) toluenediamine; 3,5-dimethylthio-(2,4- or 2,6-)toluenediamine; 3,5-diethylthio-(2,4- or 2,6-) toluenediamine: 2,2′-dichloro-3,3′,5,5′-tetraethyl-4,4′-diamino-diphenylmethane; polytetramethyleneglycol-di(p-aminobenzoate); 4,4′-bis(sec-butylamino)-dicyclohexylmethane; and mixtures thereof.

6. The method of claim 5 , wherein the amine-terminated chain extender is dimethylthiotoluenediamine.

7. The method of claim 5 , wherein the amine-terminated chain extender is diethyltoluenediamine.

8. The method of claim 1 , wherein the first prepolymer contains 0.1 to 20 weight percent unreacted amine groups.

9. The method of claim 1 , wherein the second prepolymer contains 0.1 to 15 weight percent unreacted isocyanate groups.

10. The method of claim 1 , wherein the isocyanate-terminated second prepolymer and amine chain extender are reacted so that the stoichiometric ratio of isocyanate to amine groups is in the range of about 0.95:1.00 to about 1.10:1.00.

11. The method of claim 1 , wherein the core comprises polybutadiene rubber.

12. The method of claim 1 , wherein the core is a dual-layered core.

13. The method of claim 1 , wherein the cover is dual-layered cover.

14. The method of claim 1 , wherein the golf ball further comprises an intermediate layer disposed between the core and cover.

15. The method of claim 14 , wherein the core has a diameter of about 1.26 to about 1.60 inches and surface hardness in the range of about 30 to about 65 Shore D.

16. The method of claim 14 , wherein the intermediate layer has a thickness of about 0.015 to about 0.120 inches and surface hardness in the range of about 45 to about 75 Shore D.

17. The method of claim 14 , wherein the cover layer has a thickness of about 0.015 to about 0.090 inches and material hardness in the range of about 40 to about 65 Shore D.