The present invention is directed towards a multi-layered core golf ball that comprises a thermoplastic inner casing layer molded between two polybutadiene core layers to create a faster golf ball with less spin, by designing a ball that has more of the stored energy of the core released at impact. One inner casing layer and/or an outer core layer is comprised of a partially or fully neutralized ionomer.
1. A golf ball comprising:
an inner core having a specific gravity of less than 1.05 g/cc with a compression of greater than 70;
an inner casing layer disposed around the inner core, the inner casing layer having a flexural modulus greater than 30,000 psi, a Shore C hardness greater than 80, and a thickness less than about 0.060 inch;
an outer core layer encompassing the inner casing layer, the outer core layer having a flexural modulus of less than 30 kpsi, a Shore C hardness less than 80, a specific gravity of less than 1.05 g/cc, and a thickness less than about 0.050 inch;
an outer casing layer having a flex modulus greater than 60 kpsi, a thickness less than about 0.030 inch, and a specific gravity greater than 1.25 g/cc; and
an outer cover having a hardness of less than 65 Shore D, and a thickness less than 0.040 inch.
2. The golf ball according to claim 1 , wherein the specific gravity of the outer casing layer is greater than 2.0 g/cc.
3. The golf ball according to claim 1 , wherein the inner core is formed from a polybutadiene material.
4. The golf ball according to claim 1 , wherein the inner casing is formed from a thermoplastic material.
5. The golf ball according to claim 1 , wherein the inner casing is formed from a fully neutralized ionomer.
6. The golf bail according to claim 1 , wherein the inner casing layer is formed from an ionomer resin with a fully neutralized acid moiety.
7. The golf ball according to claim 4 , wherein the inner casing has a thickness of less than 0.030 inch.
8. The golf ball according to claim 4 , wherein the inner casing has a thickness of less than 0.025 inch.
9. The golf ball according to claim 1 , wherein the outer core layer is formed from a polybutadiene material comprising less than 20 phr of a cross-linking material formed from the salt of an alpha, beta-ethylinically unsaturated carboxylic acid.
10. The golf ball according to claim 9 , wherein the outer core layer has a thickness of less than 0.040 inch.
11. The golf ball according to claim 9 , wherein the outer core layer has a thickness of less than 0.030 inch.
12. The golf ball according to claim 1 , wherein the outer casing layer is formed from a thermoplastic polymer comprising a filler having a specific gravity greater than the thermoplastic polymer.
13. The golf ball according to claim 12 , wherein the outer casing layer has a thickness of less than 0.020 inch and a specific gravity greater than 2.25 g/cc.
14. The golf ball according to claim 12 , wherein the outer casing layer has a thickness of less than 0.010 inch and a specific gravity greater than 3.2 g/cc.
15. The golf ball according to claim 1 , wherein the outer cover comprises polyurethane or polyurea.
16. The golf ball according to claim 1 , wherein the outer cover has a Shore D hardness of less than 60 D.
17. A golf ball comprising:
an inner core having a specific gravity of less than 1.2 g/cc with a compression of less than 70;
a thermoplastic inner casing disposed around the inner core, the inner casing having a flexural modulus greater than 30,000 psi, and a thickness of less than 0.10 inch;
an outer core layer having a specific gravity of less than 1.10 g/cc, a thickness of less than about 0.15 inch, and a Shore D hardness of at least 30; and
an outer cover layer having a Shore D hardness of less than 65, and a thickness of less than 0.04 inch.
18. The golf ball according to claim 17 , wherein the inner core is formed from a composition comprising polybutadiene.
19. The golf ball according to claim 17 , wherein the outer core layer is formed from a composition comprising polybutadiene.
20. The golf ball according to claim 17 , wherein the inner core has a specific gravity of less than 1.05 g/cc.
21. The golf ball according to claim 19 , wherein the outer core layer has a thickness of less than 0.10 inch.
22. The golf ball according to claim 19 , wherein the outer core layer has a Shore D hardness of greater than 40.
23. The golf ball according to claim 19 , wherein the outer core layer comprises less than 20 phr of a cross-linking material formed from the salt of an alpha, beta—ethylinically unsaturated carboxylic acid.
24. A golf ball according to claim 17 , wherein the inner casing layer is formed from an ionomer resin having a fully neutralized acid moiety.
25. A golf ball according to claim 17 , wherein the inner core has a diameter greater than 1.445 inches.