Thermoplastic multi-layer golf ball
View Patent ↗A thermoplastic multi-layer golf ball has a core center having a diameter from about 21 mm to about 29 mm and including a first thermoplastic material having a first flexural modulus of less than about 15,000 psi, a core layer disposed radially outward from the core center with a thickness of at least about 4 mm and a second thermoplastic material having a second flexural modulus of up to about 15,000 psi that is greater than the first flexural modulus, and a cover disposed radially outward from the core layer. The cover comprises a third thermoplastic material having a third flexural modulus. The first thermoplastic material and the second thermoplastic material each includes an ionomer resin, and these ionomer resins may be the same as or different from each other.
1. A golf ball, comprising:
a core center having a diameter from about 21 mm to about 29 mm and comprising a first thermoplastic material having a first flexural modulus of less than about 15,000 psi;
a core layer disposed radially outward from the core center, wherein the core layer has a thickness of at least about 4 mm and comprises a second thermoplastic material having a second flexural modulus of up to about 15,000 psi; and
a cover disposed radially outward from the core layer, wherein the cover comprises a third thermoplastic material having a third flexural modulus,
wherein the second flexural modulus is greater than the first flexural modulus and wherein the first thermoplastic material and the second thermoplastic material each comprises an ionomer resin, which may be the same as or different from each other; and
further comprising a second core layer having a thickness of up to about 2 mm disposed between the core layer and the cover, wherein the second core layer comprises a fourth thermoplastic material with a fourth flexural modulus of at least about 40,000 psi and the third flexural modulus is up to about 3,000 psi.
2. A golf ball according to claim 1 , wherein the specific gravity of the core layer and the specific gravity of the core center differ by at least about 0.1.
3. A golf ball according to claim 2 , wherein the specific gravity of the core layer is at least about 0.1 greater than the specific gravity of the core center.
4. A golf ball according to claim 2 , wherein the specific gravity of the core center is at least about 0.1 greater than the specific gravity of the core layer.
5. A golf ball according to claim 1 , wherein the core layer has a thickness of at least about 5 mm.
6. A golf ball according to claim 1 , wherein the first flexural modulus is up to about 10,000 psi.
7. A golf ball according to claim 1 , wherein the third flexural modulus is greater than the second flexural modulus.
8. A golf ball according to claim 1 , wherein the third thermoplastic material comprises an ionomer resin that may be the same as or different from the ionomer resin of the first thermoplastic material or the ionomer resin of the second thermoplastic material.
9. A golf ball according to claim 1 , wherein the third flexural modulus is at least about 35,000 psi.
10. A golf ball according to claim 1 , wherein the fourth flexural modulus is greater than the second flexural modulus.
11. A golf ball according to claim 1 , wherein the fourth thermoplastic material comprises an ionomer resin which may be the same or different from the ionomer resin of the first thermoplastic material and the ionomer resin of the second thermoplastic material.
12. A golf ball according to claim 11 , wherein the polymeric portions of the first thermoplastic material, the second thermoplastic material, and the fourth thermoplastic material consist essentially of the ionomer resins.
13. A golf ball according to claim 12 , wherein the cover layer comprises a non-ionomeric material.
14. A golf ball according to claim 13 , wherein the cover layer comprises a polyurethane elastomer.
15. A golf ball according to claim 1 , wherein the golf ball is free from a thermoset rubber layer.