GOLF BALLS HAVING METAL-CONTAINING PLASTICIZED THERMOPLASTIC INNER CORES AND THERMOSET OUTER CORES

摘要

Multi-piece golf balls containing a dual-layered core structure are provided. The core structure includes a small, heavy inner core (center) having a relatively high specific gravity, and a surrounding outer core layer. The layers of the core structure may have different hardness gradients. The center of the core comprises a metal material such as copper, steel, brass, tungsten, titanium, aluminum, and alloys thereof preferably dispersed in a thermoplastic polymeric matrix. Different plasticizer such as fatty acid esters may be used. The outer core layer is preferably formed from a thermoset composition such as polybutadiene. The resulting ball has high resiliency and good spin.

主权项

1. A golf ball, comprising:
i) an inner core layer comprising a thermoplastic composition, the inner core having 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, the thermoplastic composition comprising;
a) an acid copolymer of ethylene and an α,β-unsaturated carboxylic acid, optionally including a softening monomer selected from the group consisting of alkyl acrylates and methacrylates;b) a plasticizer;c) a cation source present in an amount sufficient to neutralize from about 0 to about 100% of all acid groups present in the composition; andd) a metal material; and ii) an outer core layer comprising a thermoset composition, the outer core layer being disposed about the inner core layer and having an outer surface hardness (Houter surface of OC) and a midpoint hardness (Hmidpoint of OC), the Houter surface of OC being greater than the Hmidpoint of OC to provide a positive hardness gradient, wherein the center hardness of the inner core (Hinner core center) is in the range of about 10 Shore C to about 70 Shore C and the outer surface hardness of the outer core layer (Houter surface of OC) is in the range of about 20 Shore C to about 95 Shore C to provide a positive hardness gradient across the core assembly; and iii) a cover having at least one layer disposed about the outer core layer.