Multi-piece golf balls having a solid core and cover are provided. The ball contains a small, heavy inner core and surrounding outer core layer. The inner core preferably contains metal powder such as copper, steel, brass, tungsten, titanium, nickel, iron, tin, and bronze particles dispersed in a thermoset or thermoplastic polymeric matrix. For example, a polybutadiene rubber matrix may be used. In one preferred embodiment, the inner core contains elemental iron powder. Preferably, the particles have a weight average size in the range of about 10 m to about 450 m. In one embodiment, the outer surface of the inner core has a structure with projecting members. For example, the outer surface may contain multiple projecting ribs with gaps located between the ribs. The ball includes a cover surrounding the core structure. The cover may be multi-layered.

Golf balls having a multi-layered core made of a foamed composition are provided. The core assembly preferably includes a foam inner core (center) and surrounding outer core layer. Preferably, a polyurethane foam composition is used to form the foam center. The core layers have different hardness gradients and specific gravity values. The foamed inner core assembly includes a geometric center, outer surface (skin), and thermal barrier layer that helps protect the foamed center region from the negative effects of high temperatures used during the ball-manufacturing process. Non-foamed thermoset materials such as polybutadiene rubber may be used to form the thermal barrier layer. The foam cores have good resiliency, thermal stability, and durability over a wide temperature range. The ball further includes a cover that may be multi-layered.

Golf ball having CoR of at least 0.700 and Atti compression of at least about 50 and comprising layer comprising a mixture of ionomer composition and a plurality of particulates, at least some being surface-treated with alkoxylated siloxanes and/or polyether-modified siloxanes, and selected from titanium dioxide particles, barium sulfate particles, zinc sulfide particles, and/or zinc oxide particulates. At least some particulates may be contacted with compound having the formula:

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Compound (I) may be included in amount of 0.01 to 2% by weight based on total weight of portion of plurality being contacted. The plurality may be included in mixture in amount such that the layer has specific gravity of from 0.5 to about 5.0, tensile strength of from about 300 psi to about 50,000 psi, and elongation at break of from about 20% to about 1000%, each being greater than that of the ionomer composition portion of the mixture.

In a multi-piece solid golf ball made up of, successively, a core, an intermediate layer and a cover having numerous dimples on the surface thereof, the intermediate layer is formed of a resin material and the cover is formed of a urethane resin material, each having a specific respective Shore D hardness. The ball has a specific (intermediate layer thickness)/(core diameter) value and a specific (cover thickness)/(core diameter) value, and the core has a specific deflection. The sphere consisting of the core encased by the intermediate layer has an initial velocity A and the core has an initial velocity B which together satisfy the condition AB0 m/s. This golf ball provides an increased distance and has both a soft feel when played and a high durability to repeated impact.

Multi-piece golf balls containing a multi-layered core structure are provided. The core structure includes a small, heavy inner core (center) having a relatively high specific gravity, an intermediate core layer, 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 dispersed in a thermoset polymeric matrix. The intermediate core layer is preferably formed from a first thermoplastic composition such as an ethylene acid copolymer ionomer resin; and the outer core layer is preferably formed from a second thermoplastic composition. The resulting ball has high resiliency and good spin control.

The golf ball includes a core having an inner layer core and an outer layer core, a single-layered intermediate layer and cover, wherein the inner layer core is formed of a rubber composition, the intermediate layer and the cover are formed of a resin composition, and a relationship between an initial velocity of the inner layer core, an initial velocity of the entire core, an initial velocity of an intermediate layer-encased sphere, and an initial velocity of a ball satisfies the following conditions:

(initial velocity of ball)<(initial velocity of intermediate layer-encased sphere)

(initial velocity of intermediate layer-encased sphere)?(initial velocity of entire core)?0.70 (m/s)

(initial velocity of entire core)?(initial velocity of inner layer core)?0.20 (m/s) and a specific gravity of the intermediate layer and a deflection of the golf ball when compressed under a predetermined load are set within specific ranges.

In a golf ball having a core, envelope layer, intermediate layer and cover, the core has a specific hardness profile, the resin materials making up either or both of the envelope layer and the intermediate layer has a material hardness on the Shore D hardness scale of at least 65 and has a specific gravity of at least 1.05, and the Shore C hardness relationships among the core center, surface of the envelope-encased layer and surface of the intermediate layer-encased sphere satisfy the following conditions:
surface hardness of envelope layer-encased sphere<surface hardness of intermediate layer-encased sphere,(1)
surface hardness of intermediate layer-encased sphere?center hardness of core?40.(2)
This ball achieves a good distance on shots with utility and iron clubs, is receptive to spin in the short game, and has a soft feel at impact on all shots, making it useful to amateur golfers.

The golf ball includes a core, an intermediate layer, and a cover, in which the core is formed of a rubber composition into a single layer or a plurality of layers, the intermediate layer and the cover are both formed of a single-layer resin composition, and a relationship between an initial velocity of the core, an initial velocity of a sphere (intermediate layer-encased sphere) in which the core is encased with the intermediate layer, and an initial velocity of a sphere (ball) in which the intermediate layer-encased sphere is encased with the cover satisfies the following two conditions:

(initial velocity of ball)<(initial velocity of intermediate layer-encased sphere)

0.60?(initial velocity of intermediate layer-encased sphere)?(initial velocity of core)?1.00 (m/s). and the specific deflection is 3.00 mm or less, and a specific gravity of the intermediate layer is 1.05 or more.

Multi-layered golf balls having a core, intermediate layer, and cover are provided. The ball includes a non-foamed inner core (center) made of a thermoplastic or thermoset composition such as polybutadiene rubber. An intermediate layer comprising a foamed composition, such as polyurethane foam, is disposed about the inner core. The foamed intermediate layer may have a specific gravity gradient within the layer, wherein the outer surface specific gravity is greater than the midpoint specific gravity. Ball constructions having two intermediate layers, wherein at least one layer is a foamed layer can be made. A cover having at least one layer is disposed about the intermediate layer.

Multi-layered golf balls having a dual-layered core and cover of at least one layer are provided. The dual-core construction includes a non-foamed inner core (center) made of a thermoplastic or thermoset composition such as polybutadiene rubber. An outer core layer comprising a foamed composition, such as polyurethane foam, is disposed about the inner core. In one version, the foamed outer core layer is made of a relatively soft foam composition having low flex modulus and density. The foamed outer core layer may specific gravity gradient within the layer, wherein the outer surface specific gravity is greater than the midpoint specific gravity. A cover may be disposed about the core structure. For example, an inner cover made of ethylene acid copolymer ionomer and outer cover made of polyurethane may be used.