Multi-layered cores with thermoplastic and thermoset layers for golf balls
View Patent ↗Multi-piece golf balls containing a multi-layered core structure having layers with different hardness gradients and specific gravities are provided. The core structure includes a small, heavy inner core (center) having a relatively high specific gravity with metal material preferably dispersed in a first thermoset composition. The intermediate core layer is preferably formed from a thermoplastic composition such as an ethylene acid copolymer ionomer resin; and the outer core layer is preferably formed from a second thermoset composition. The resulting ball has high resiliency and good spin control.
1. A golf ball, comprising:
a multi-layered core including i) an inner core comprising a metal material, the inner core having a diameter in the range of about 0.100 to about 1.100 inches, a specific gravity (SG inner ), and an outer surface hardness (H center surface ) and a center hardness (H center material ), the H center surface being the same or less than the H center material to provide a zero or negative hardness gradient, wherein the inner core has a diameter in the range of about 0.100 to about 0.500 inches and specific gravity in the range of about 1.60 to about 6.25 g/cc;
ii) an intermediate core layer comprising a thermoplastic material, the intermediate layer being disposed about the inner core and having a thickness in the range of about 0.050 to about 0.400 inches, a specific gravity (SG intermediate ), and an outer surface hardness (H outer surface of IC ) and an inner surface hardness (H inner surface of IC ), the H outer surface of IC being greater than the H inner surface of IC to provide a positive hardness gradient; and
iii) an outer core layer comprising a thermoset material, the outer core layer being disposed about the inner core and having a thickness in the range of about 0.200 to about 0.750 inches, a specific gravity (SG outer ), and an outer surface hardness ((H outer surface of OC ) of 40 to 85 Shore C and an inner surface hardness (H inner surface of OC ) of 42 to 87 Shore C, the H outer surface of OC being the same or less than the H inner surface of OC to provide a zero or negative hardness gradient, wherein the SG inner is greater than the SG outer and SG intermediate ; and
a cover having at least one layer disposed about the multi-layered core.
2. The golf ball of claim 1 , wherein the outer core layer has a thickness in the range of about 0.250 to about 0.750 inches and specific gravity in the range of about 0.60 to about 2.90 g/cc.
3. A golf ball, comprising:
a multi-layered core including i) an inner core comprising a metal material, the the inner core having a diameter in the range of about 0.100 to about 1.100 inches, a specific gravity (SG inner ), and an outer surface hardness (H center surface ) and a center hardness (H center material ), the H center surface being the same or less than the H center material to provide a zero or negative hardness gradient;
ii) an intermediate core layer comprising a thermoplastic material, the intermediate layer being disposed about the inner core and having a thickness in the range of about 0.050 to about 0.400 inches, a specific gravity (SG intermediate ) and an outer surface hardness (H outer surface of IC ) and an inner surface hardness (H inner surface of IC ), the H outer surface of IC being the same or less than the H inner surface of IC to provide a zero or negative hardness gradient; and
iii) an outer core layer comprising a thermoset material, the outer core layer being disposed about the inner core and having a thickness in the range of about 0.200 to about 0.750 inches, a specific gravity (SG outer ), and an outer surface hardness ((H outer surface of OC ) of 42 to 92 Shore C and an inner surface hardness (H inner surface of OC ) of 40 to 89 Shore C, the H outer surface of OC being greater than the H inner surface of OC to provide a positive hardness gradient, wherein the SG inner is greater than the SG outer , and SG intermediate ; and
a cover having at least one layer disposed about the multi-layered core.
4. The golf ball of claim 3 , wherein the inner core has a diameter in the range of about 0.100 to about 0.500 inches and specific gravity in the range of about 1.60 to about 6.25 g/cc.
5. The golf ball of claim 3 , wherein the outer core layer has a thickness in the range of about 0.250 to about 0.750 inches and specific gravity in the range of about 0.60 to about 2.90 g/cc.
6. A golf ball, comprising:
a multi-layered core including i) an inner core comprising a metal material, the inner core having a diameter in the range of about 0.100 to about 1.100 inches, a specific gravity (SG inner ), and an outer surface hardness (H center surface ) and a center hardness (H center material ), the H center surface being greater than the H center material provide a positive hardness gradient;
ii) an intermediate core layer comprising a thermoplastic material, the Intermediate layer being disposed about the inner core and having a thickness in the range of about 0.050 to about 0.400 inches, a specific gravity (SG intermediate ), and an outer surface hardness (H outer surface of IC ) and an inner surface hardness (H inner surface of IC ), the H outer surface of IC being the same or less than the H inner surface of IC to provide a zero or negative hardness gradient; and
iii) an outer core layer comprising a thermoset material, the outer core layer being disposed about the inner core and having a thickness in the range of about 0.200 to about 0.750 inches, a specific gravity (SG outer ), and an outer surface hardness ((H outer surface of OC ) of 40 to 85 Shore C and an inner surface hardness (H inner surface of OC ) of 42 to 87 Shore C, the H outer surface of OC being the same or less than the H inner surface of OC to provide a zero or negative hardness gradient, wherein the SG inner is greater than the SG outer ; and
a cover having at least one layer disposed about the multi-layered core.
7. The golf ball of claim 6 , wherein the inner core has a diameter in the range of about 0.100 to about 0.500 inches and specific gravity in the range of about 1.60 to about 6.25 g/cc.
8. The golf ball of claim 6 , wherein the outer core layer has a thickness in the range of about 0.250 to about 0.750 Inches and specific gravity in the range of about 0.60 to about 2.90 g/cc.