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.

A golf ball is provided that includes at least two layers of material disposed between a spherical core and a cover layer, wherein the elastic modulus of each is within three orders of magnitude of each adjacent layer or core. The spherical core can be a hollow metal core. This results in a golf ball that is legal for play and capable of drive distances essentially equivalent to those of currently available high performance golf balls, but also provides a golf ball that has less hook and slice during play.

A golf ball is provided that has a spherical core exhibiting a stiffness from 400 MPa to 200 GPa. The stiffness of the core may be controlled by adjusting the materials of construction and the ratio of the materials. This results in a golf ball that is legal for play and capable of drive distances essentially equivalent to those of currently-available high performance golf balls, but also provides a golf ball that has less hook and slice during play.

An ultra-low compression golf ball is disclosed herein. The core preferably has a PGA compression less than 30. The mantle layer and cover have approximately the same thickness. The cover comprises a thermoplastic polyurethane material and has a specific gravity greater than the core and mantle layer. The golf ball has a PGA compression less than 75 and a COR of at least 0.780.

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. In one preferred embodiment, each core layer has a positive hardness gradient. The center of the core comprises a metal material such as copper, steel, brass, tungsten, titanium, aluminum, and alloys thereof. The intermediate core layer is preferably formed from a thermoset composition such as polybutadiene rubber, and the outer core layer is preferably formed from a thermoplastic composition such as an ethylene acid copolymer. The resulting ball has high resiliency and good spin control.

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 materials such as copper, steel, brass, tungsten, titanium, nickel, iron, tin, and bronze particles dispersed in a thermoset or thermoplastic polymeric matrix. Preferably, the polymeric matrix comprises polybutadiene rubber. The outer surface of the inner core preferably has a non-uniform structure and includes 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.

An ultra-low compression golf ball is disclosed herein. The core preferably has a PGA compression less than 30. The mantle layer and cover have approximately the same thickness. The cover comprises a thermoplastic polyurethane material and has a specific gravity greater than the core and mantle layer. The golf ball has a PGA compression less than 75 and a COR of at least 0.780.

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 plasticized thermoplastic polymeric matrix. Different plasticizer such as fatty acid esters may be used. The outer core layer also is preferably formed from a thermoplastic composition such as an ethylene acid copolymer ionomer resin. The resulting ball has high resiliency and good spin.

A golf ball is provided that includes at least two layers of material disposed between a spherical core and a cover layer, wherein the elastic modulus of each is within three orders of magnitude of each adjacent layer or core. The spherical core can be a hollow metal core. This results in a golf ball that is legal for play and capable of drive distances essentially equivalent to those of currently available high performance golf balls, but also provides a golf ball that has less hook and slice during play.

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 materials such as copper, steel, brass, tungsten, titanium, nickel, iron, tin, and bronze particles dispersed in a thermoset or thermoplastic polymeric matrix. Preferably, the polymeric matrix comprises polybutadiene rubber. The outer surface of the inner core preferably has a non-uniform structure and includes 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.