Multi-layer core golf ball
View Patent ↗Golf balls consisting of a multi-layer core and a cover are disclosed. The multi-layer core comprises a soft thermoset rubber center, a stiff thermoplastic intermediate core layer, and a thin thermoset rubber outer core layer. The maximum hardness of the core is a point or region located at a distance of from 0.1 mm to 8.0 mm measured radially inward from the outer surface of the core. The maximum core hardness is preferably at least 10% greater than the outer surface hardness of the core.
1. A golf ball comprising:
a core consisting of:
a center formed from a first diene rubber composition and having a diameter of from 1.000 inches to 1.580 inches, a center hardness of from 40 Shore C to 70 Shore C, and a surface hardness (SH center ) of from 50 Shore C to 85 Shore C;
an intermediate core layer formed from a thermoplastic composition and having a thickness of from 0.005 inches to 0.100 inches and an outer surface hardness of 60 Shore D or greater; and
an outer core layer formed from a second diene rubber composition and having a thickness of from 0.010 inches to 0.100 inches and an outer surface hardness (SH outer ) of 80 Shore C or greater;
wherein SH outer is greater than SH center ;
wherein the core has a maximum hardness (SH peak ) located at a distance of from 0.25 mm to 5.00 mm measured radially inward from the outer surface of the core; and
wherein SH peak is 10% or more higher than SH outer ; and
a cover layer having a thickness of from 0.010 inches to 0.050 inches and formed from a composition having a material hardness of less than 60 Shore D.
2. The golf ball of claim 1 , wherein SH peak is 20% or more higher than SH outer .
3. The golf ball of claim 1 , wherein SH peak is located at a distance of from 0.50 mm to 5.00 mm measure radially inward from the outer surface of the core.
4. The golf ball of claim 1 , wherein SH peak is located at a distance of from 0.50 mm to 2.50 mm measure radially inward from the outer surface of the core.
5. The golf ball of claim 1 , wherein SH peak is 20% or more higher than SH outer , and wherein SH peak is located at a distance of from 0.50 mm to 5.00 mm measure radially inward from the outer surface of the core.
6. The golf ball of claim 1 , wherein the difference between SH outer and SH center is 5 Shore C units or greater.
7. The golf ball of claim 1 , wherein the difference between SH outer and SH center is 10 Shore C units or greater.
8. The golf ball of claim 1 , wherein the center has a positive hardness gradient wherein the difference between the center hardness and the surface hardness of the center is from 10 to 45.
9. The golf ball of claim 1 , wherein the center has a diameter of from 1.300 inches to 1.490 inches, the intermediate core layer has a thickness of from 0.020 inches to 0.070 inches, and the outer core layer has a thickness of from 0.030 inches to 0.040 inches.
10. The golf ball of claim 1 , wherein the surface hardness of the intermediate core layer is 65 Shore D or greater.
11. The golf ball of claim 1 , wherein the surface hardness of the intermediate core layer is 70 Shore D or greater.
12. The golf ball of claim 1 , wherein SH outer is 85 Shore C or greater.
13. The golf ball of claim 1 , wherein the thermoplastic composition of the intermediate core layer is selected from the group consisting of partially- and fully-neutralized ionomers, and blends of two or more thereof.
14. A golf ball comprising:
a core consisting of:
a center formed from a first diene rubber composition and having a diameter of from 1.400 inches to 1.550 inches, a center hardness of from 45 Shore C to 70 Shore C, and a surface hardness (SH center ) of from 55 Shore C to 85 Shore C;
an intermediate core layer formed from a thermoplastic composition and having a thickness of from 0.020 inches to 0.070 inches and an outer surface hardness of 65 Shore D or greater; and
an outer core layer formed from a second diene rubber composition and having a thickness of from 0.020 inches to 0.050 inches and an outer surface hardness (SH outer ) of 85 Shore C or greater;
wherein SH outer is greater than SH center ;
wherein the core has a maximum hardness (SH peak ) located at a distance of from 0.50 mm to 5.00 mm measured radially inward from the outer surface of the core; and
wherein SH peak is 10% or more higher than SH outer ; and
a cover layer having a thickness of from 0.010 inches to 0.050 inches and formed from a composition having a material hardness of less than 60 Shore D, wherein the cover layer composition is selected from polyurethanes, polyureas, and polyurethane-urea hybrids.
15. The golf ball of claim 14 , wherein SH peak is 20% or more higher than SH outer .
16. The golf ball of claim 14 , wherein SH peak is located at a distance of from 0.50 mm to 2.50 mm measure radially inward from the outer surface of the core.
17. The golf ball of claim 14 , wherein SH peak is 20% or more higher than SH outer , and wherein SH peak is located at a distance of from 0.50 mm to 2.50 mm measure radially inward from the outer surface of the core.
18. The golf ball of claim 14 , wherein the difference between SH outer and SH center is 5 Shore C units or greater.
19. The golf ball of claim 14 , wherein the difference between SH outer and SH center is 10 Shore C units or greater.
20. The golf ball of claim 14 , wherein the center has a positive hardness gradient wherein the difference between the center hardness and the surface hardness of the center is from 10 to 45.