Multi-modal ionomeric golf ball compositions

1. A method of forming a golf ball, comprising the steps of:

providing a golf ball core comprising a thermoset material;

forming an in-situ multi-modal mixture by:

providing a first acid copolymer having a molecular weight of about 70,000 or greater;

providing a second acid copolymer having a molecular weight of about 40,000 or less;

providing a neutralizing agent;

mixing the first acid copolymer, the second acid copolymer, the neutralizing agent, and, optionally, a processing aid, to form the in-situ multi-modal mixture;

providing a thermoplastic polymer;

forming a cover material comprising the multi-modal mixture and about 60 percent to about 90 percent by weight of a thermoplastic polymer, wherein the cover material has a flexural modulus of about 35,000 psi to about 65,000 psi after 2 weeks;

forming a cover disposed about the core with the cover material.

2. The method of claim 1 , wherein the cover comprises an inner cover and an outer cover.

3. The method of claim 2 , wherein the inner cover comprises the cover material.

4. The method of claim 2 , wherein the outer cover comprises the cover material.

5. A method of forming a golf ball, comprising the steps of:

providing a golf ball core comprising a first material;

forming a multi-modal mixture by:

polymerizing in-situ a first acid copolymer having a molecular weight of about 70,000 or greater in the presence of a second acid copolymer having a molecular weight of about 40,000 or less to form an in-situ polymer mixture and an optional third acid copolymer having a molecular weight different from the first and second acid copolymers;

providing a neutralizing agent;

processing the in-situ polymer mixture with the neutralizing agent, and, optionally, a processing aid, to form the multi-modal mixture;

forming a composition by blending the multi-modal mixture with about 60 percent to about 90 percent thermoplastic polymer by weight of the composition, wherein the composition has a flexural modulus of about 35,000 psi to about 65,000 psi after 2 weeks; and

forming a cover disposed about the core with the composition;

wherein the first material differs from the composition.

6. The method of claim 5 , wherein the cover comprises an inner cover and an outer cover.

7. The method of claim 6 , wherein the inner cover comprises the composition.

8. The method of claim 6 , wherein the outer cover comprises the composition.

9. The golf ball of claim 1 , wherein the thermoset material comprises polybutadiene.

10. The golf ball of claim 5 , wherein the first material comprises polybutadiene.

11. A method of forming a golf ball, comprising the steps of:

providing a golf ball core comprising a thermoset material;

providing a first acid copolymer having a first molecular weight of about 70,000 or greater;

providing a second acid copolymer having a second molecular weight of about 40,000 or less;

providing a neutralizing agent;

forming an in-situ multi-modal mixture comprising the first acid copolymer, the second acid copolymer, the neutralizing agent, and optionally, the processing aid,

blending about 60 percent to about 90 percent by weight of an ionomer with the in-situ multi-modal mixture to form a composition, wherein the composition has a flexural modulus of about 35,000 psi to about 65,000 psi after 2 weeks;

forming a layer disposed about the core with the composition resulting in an inner ball; and

forming a cover about the inner ball.

12. The method of claim 11 , wherein the step of forming a cover comprises casting a polyurethane material about the inner ball.

13. The method of claim 11 , wherein the thermoset material comprises polybutadiene.

14. The method of claim 11 , wherein the cover comprises polyurethane or polyurea.

15. The method of claim 11 , wherein the processing aid comprises an organic acid or organic acid.

16. The method of claim 1 , wherein the step of providing a golf ball core comprises providing a core having a diameter ranging from 1.50 to 1.60 inches.

17. The method of claim 16 , wherein the step of forming a cover comprises forming a cover having a thickness ranging from about 0.03 inches to 0.07 inches.

18. The method of claim 1 , further comprising the steps of providing a third acid copolymer having a molecular weight that differs from the molecular weights of the first and second acid copolymers by at least about 5000 and mixing the third acid copolymer with the first acid copolymer, the second acid copolymer, the neutralizing agent, and, optionally, a processing aid, to form the in-situ multi-modal mixture.

19. The method of claim 5 , wherein the molecular weight of the optional third acid copolymer differs from the molecular weights of the first and second acid copolymers by at least about 5000.

20. The method of claim 11 , wherein the composition has a flexural modulus of about 37,000 psi to about 62,000 psi after 2 weeks.