Golf ball with small inner core
The present invention is directed to golf balls having a resilient inner core and outer core made of a material substantially free of fillers. The invention also encompasses golf balls wherein the inner and outer cores are not made of a thermoplastic material. The invention encompasses golf balls having an inner core, an outer core, an inner cover, and an outer cover wherein the inner core is encased by an outer core wherein the outer core has a volume greater than the inner core, inner cover, or outer cover and the inner core is made of a material substantially free of fillers. The volume relationship of the inner core (V 12 ), outer core (V 14 ), inner cover (V 16 ), and outer cover (V 18 ) is represented by the mathematical relationship: V 14 >⅗(V 12 +V 16 +V 18 ), wherein V 12 ≧V 18 ≧V 16 . Also, the inner core has a specific gravity ρ 12 , the outer core has a specific gravity ρ 14 , the inner cover has a specific gravity ρ 16 , and the outer cover has a specific gravity ρ 18 , wherein the relationship between the specific gravities is expressed by the mathematical expression: ρ 16 ≧ρ 18 ≧ρ 12 ≧ρ 14 .
1. A golf ball comprising an inner core, an outer core, an inner cover, and an outer cover wherein the inner core is encased by an outer core wherein the outer core has a volume greater than the inner core, inner cover, or outer covers and the outer core is comprised of a highly neutralized polymer, is substantially free of fillers, and the diameter of the inner core is in the range of about 1.35 inch to about 0.75 inch,
wherein the inner core has a specific gravity ρ 12 , the outer core has a specific gravity ρ 14 , the inner cover has a specific gravity ρ 16 , and the outer cover has a specific gravity ρ 18 , wherein the relationship between the specific gravities is expressed by the mathematical expression: ρ 16 ≧ρ 18 ≧ρ 12 ≧ρ 14 , and
wherein at least one of the inner cover and outer cover comprises at least one material selected from the group consisting of reactive coating materials, non-reactive coating materials, casting materials and RIM materials.
2. The golf ball according to claim 1 , wherein the material comprises polyurethane.
3. The golf ball according to claim 1 , wherein the material comprises polyurea.
4. The golf ball according to claim 1 , wherein the inner cover layer has a Shore D hardness of greater than about 65.
5. The golf ball according to claim 1 , wherein the inner cover layer comprises a flexural modulus of greater than about 60,000 psi.
6. The golf ball according to claim 1 , wherein the outer cover layer has a Shore D hardness of from about 30 to about 60.
7. The golf ball according to claim 1 , wherein the inner cover has a thickness of less than about 0.020 inch.
8. The golf ball according to claim 1 , wherein the inner cover has a specific gravity greater than about 2.
9. The golf ball according to claim 1 , wherein the outer cover has a thickness of about 0.035 inch or less.
10. A golf ball comprising an inner core, an outer core, an inner cover, and an outer cover wherein the inner core is encased by an outer core wherein the outer core has a volume greater than the inner core, inner cover, or outer cover, and the inner core is comprised of a highly neutralized polymer, is substantially free of fillers, and the outer core is comprised of a highly neutralized polymer,
wherein the inner core has a specific gravity ρ 12 , the outer core has a specific gravity ρ 14 , the inner cover has a specific gravity ρ 16 , and the outer cover has a specific gravity ρ 18 , wherein the relationship between the specific gravities is expressed by the mathematical expression: ρ 16 ≧ρ 18 ≧ρ 12 ≧ρ 14 , and
wherein at least one of the inner cover and outer cover comprises at least one material selected from the group consisting of reactive coating materials, non-reactive coating materials, casting materials and RIM materials.
11. The golf ball according to claim 10 , wherein the material comprises polyurethane.
12. The golf ball according to claim 10 , wherein the material comprises polyurea.
13. The golf ball according to claim 10 , wherein the inner cover layer has a Shore D hardness of greater than about 65.
14. The golf ball according to claim 10 , wherein the inner cover layer comprises a flexural modulus of greater than about 60,000 psi.
15. The golf ball according to claim 10 , wherein the outer cover layer has a Shore D hardness of from about 30 to about 60.
16. The golf ball according to claim 10 , wherein the inner cover has a thickness of less than about 0.020 inch.
17. The golf ball according to claim 10 , wherein the inner cover has a specific gravity greater than about 2.
18. The golf ball according to claim 10 , wherein the outer cover has a thickness of about 0.035 inch or less.