Multi-layer core golf ball
View Patent ↗Golf balls comprising a multi-layer core and a cover are disclosed. The multi-layer core comprises a layer formed from a highly neutralized polymer composition, a layer formed from an additional thermoplastic composition, and an outermost layer formed from a thermoset rubber.
1. A golf ball comprising:
an inner core layer formed from a first thermoset rubber composition and having a diameter of from 0.500 inches to 1.580 inches and a positive hardness gradient wherein the difference between the center hardness and the surface hardness of the inner core layer is from 10 to 45 Shore C units;
a first intermediate core layer formed from a highly neutralized polymer composition and having a thickness of from 0.005 inches to 0.100 inches and a surface hardness of from 50 Shore C to 85 Shore C;
a second intermediate core layer formed from a thermoplastic composition selected from the group consisting of partially- and fully-neutralized ionomers optionally blended with a maleic anhydride-grafted non-ionomeric polymer, polyesters, polyethers, polyamides, and blends of two or more thereof, and having a thickness of from 0.005 inches to 0.100 inches;
an outer core layer formed from a second thermoset rubber composition and having a thickness of from 0.010 inches to 0.100 inches and a surface hardness of 50 Shore C or greater; and
a cover layer having a thickness of from 0.010 inches to 0.050 inches and a surface hardness of 65 Shore D or less.
2. The golf ball of claim 1 , wherein the inner core layer has a center hardness of from 40 Shore C to 65 Shore C, a surface hardness of from 50 Shore C to 85 Shore C, and a compression of from 20 to 60.
3. The golf ball of claim 1 , wherein the inner core layer has a center hardness of from 40 Shore C to 65 Shore C, a surface hardness of 80 Shore C or greater, and a compression of from 60 to 80.
4. The golf ball of claim 1 , wherein the second intermediate core layer has a surface hardness of greater than 50 Shore D.
5. The golf ball of claim 1 , wherein the second intermediate core layer has a surface hardness of 60 Shore D or less.
6. A golf ball consisting essentially of:
an inner core layer formed from a first diene rubber composition and having a diameter of from 0.500 inches to 1.580 inches and a positive hardness gradient wherein the difference between the center hardness and the surface hardness of the inner core layer is from 10 to 45 Shore C units;
a first intermediate core layer formed from a highly neutralized polymer composition and having a thickness of from 0.005 inches to 0.100 inches and a surface hardness of from 50 Shore C to 85 Shore C;
a second intermediate core layer formed from a thermoplastic composition selected from the group consisting of partially- and fully-neutralized ionomers optionally blended with a maleic anhydride-grafted non-ionomeric polymer, polyesters, polyethers, polyamides, and blends of two or more thereof, and having a thickness of from 0.005 inches to 0.100 inches;
an outer core layer formed from a second diene rubber composition and having a thickness of 0.010 inches to 0.100 inches and a surface hardness of 80 Shore C or greater; and
a cover layer formed from a polyurethane, a polyurea, or a copolymer or blend thereof, and having a thickness of from 0.010 inches to 0.050 inches and a surface hardness of 65 Shore D or less.
7. The golf ball of claim 6 , wherein the inner core layer has a center hardness of from 40 Shore C to 65 Shore C, a surface hardness of from 50 Shore C to 85 Shore C, and a compression of from 20 to 60; and wherein the surface hardness of the outer core layer is greater than the surface hardness of the inner core layer.
8. The golf ball of claim 6 , wherein the inner core layer has a center hardness of from 40 Shore C to 65 Shore C, a surface hardness of 80 Shore C or greater, and a compression of from 60 to 80.
9. The golf ball of claim 6 , wherein the second intermediate core layer has a surface hardness of greater than 50 Shore D.
10. The golf ball of claim 6 , wherein the second intermediate core layer has a surface hardness of 60 Shore D or less.