GOLF BALL CORES HAVING FOAM CENTER AND THEMOPLASTIC OUTER LAYERS

摘要

Golf ball multi-layered core sub-assemblies and the resulting golf balls are provided. The core structure includes a foam inner core (center); and intermediate and outer core layers. Foamed polyurethane is preferably used to make the inner core. The intermediate and outer core layers are preferably made from non-foamed thermoplastic compositions such as ethylene acid copolymer ionomer. In an alternative version, the intermediate core layer may be made of a thermoset rubber such as polybutadiene. The core layers have different hardness and specific gravity levels. The core structure and resulting ball have relatively good resiliency.

主权项

1. A core assembly for a golf ball, comprising:
i) an inner core layer comprising a foamed composition, the inner core layer having a diameter in the range of about 0.100 to about 1.100 inches, a specific gravity (SGinner), and an outer surface hardness (Hinner core surface) and a center hardness (Hinner core center), the Hinner core surface being greater than the Hinner core center to provide a positive hardness gradient; ii) an intermediate core layer comprising a thermoplastic or thermoset 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 (SGintermediate), and an outer surface hardness (Houter surface of IC) and an inner surface hardness (Hinner surface of IC), the Houter surface of IC being greater than the Hinner surface of IC to provide a positive hardness gradient; and iii) an outer core layer comprising a thermoplastic material, the outer core layer being disposed about the intermediate core layer and having a thickness in the range of about 0.100 to about 0.750 inches, a specific gravity (SGouter), and an outer surface hardness (Houter surface of OC) and an inner surface hardness (Hinner surface of OC), the Houter surface of OC being the same or less than the Hinner surface of OC to provide a zero or negative hardness gradient, wherein the SGouter, is greater than the SGinner, and the SGintermediate is greater than the SGinner.