An object of the present invention is to provide a golf ball traveling a great distance on driver shots and on iron shots. The present invention provides a golf ball comprising a spherical core including an inner layer and an outer layer, and a cover, wherein a difference (H.sub.X+1−H.sub.X−1) between a hardness (H.sub.X+1) at a point outwardly away in a radial direction from a boundary between the inner layer and the outer layer of the spherical core by 1 mm and a hardness (H.sub.X−1) at a point inwardly away in the radial direction from the boundary between the inner layer and the outer layer of the spherical core by 1 mm is 0 or more in Shore C hardness, a surface hardness (H.sub.X+Y) of the spherical core is more than 65 in Shore C hardness, an angle α of a hardness gradient of the inner layer is 0° or more, a difference (α−β) between the angle α and an angle β of a hardness gradient of the outer layer is 0° or more, a thickness of the cover is 3 mm or less, a difference (Hc−H.sub.x+y) between a hardness (Hc) of the cover and the surface hardness (H.sub.X+Y) of the spherical core is 2 or more in Shore C hardness, and the cover has a highest hardness among the constituent members of the golf ball.

Multi-piece golf balls containing a dual-layered core and dual-layered cover 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 core layers may have different hardness gradients. The center of the core comprises a metal material such as copper, steel, brass, tungsten, titanium, aluminum, and combinations and alloys thereof preferably dispersed in a thermoplastic polymeric matrix. The outer core layer is preferably formed from a thermoset composition such as polybutadiene. The multi-layered cores and covers have selective specific gravity relationships between the different layers. This helps provide the ball with good flight distance and spin control. The resulting balls have good resiliency and other playing performance properties.

Multi-piece golf balls containing a dual-layered core are provided. The ball further includes single or multi-layered covers. The core structure includes a small, heavy inner core (center) having a relatively high specific gravity, and a surrounding outer core layer. The core layers may have different hardness gradients. The center of the core comprises a metal material such as copper, steel, brass, tungsten, titanium, aluminum, and combinations and alloys thereof preferably dispersed in a thermoplastic polymeric matrix. The outer core layer is preferably formed from a thermoset composition such as polybutadiene. These multi-layered core constructions with metal-containing centers have selective specific gravity relationships between the different layers. This helps provide the ball with good flight distance and spin control. The resulting balls have good resiliency and other playing performance properties.

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 first thermoset composition such as polybutadiene rubber, and the outer core layer is preferably formed from a second thermoset composition. The resulting ball has high resiliency and good spin control.

Golf ball with through-hole(s) incorporating hollow air pocket(s) to produce thinner outer wall facilitating more speed and responsiveness off of the golf club's face at impact is disclosed. A thin outer wall is desirable in golf ball design. A wall that is too thick inhibits rebound and promotes fracturing. A thinner wall with structural supports allows for the outer wall to be thinned while producing an internal structure that promotes rebound and not structural failure. This volume of material formed into the volume to help resist deformation of the outer shell. The internal structure between the outer shell and inner axial shaft can be a honeycomb-like pattern or concentric rings to create more structure, less air volume and faster response. These smaller compartments of air will create more rebound because of the additional force of the more responsive inner structure providing a spring effect as well.

A golf ball comprising at least one layer consisting of a non-isocyanate-containing polyurethane composition comprising the reaction product of: at least one amine or polyamine, having an average functionality of 2.0 or greater, and at least one cyclo-carbonate. The amine may be selected for example from the group consisting of: ethylenediamine, hexamethylenediamine, or tris(2-aimnoethyl)amine, or blends thereof; and the polyamine may be selected for example from the group consisting of polyoxypropylene diamines, polyoxypropylene triamines, and combinations thereof. The cyclo-carbonate may comprise for example bis(cyclo-carbonate). Other possible reaction products include: (i) the at least one amine or polyamine and at least one epoxy-cyclo-carbonate oligomer, wherein the non-isocyanate-containing polyurethane composition can be modified with at least one of acrylic or siloxane; or (ii) the at least one amine or polyamine and at least one cyclo-carbonated soybean oil; or (iii) at least one lignin-based polyamine and at least one cyclo-carbonated soybean oil.

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 μm to about 450 μm. 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.

Multi-piece golf balls having a multi-layered solid core and multi-layered cover are provided.

A golf ball comprising a core comprising an inner core center and an outer core layer disposed over the inner core center. The inner core center has a deflection of greater than 0.210 inch under a load of 100 kilograms, and the entire the core has a deflection ranging from 0.130 inch to 0.105 inch under a load of 100 kilograms. A mantle layer is disposed over the core and a cover is disposed over the mantle.

Golf ball incorporating core consisting of: a solid inner core layer consisting of a peroxide cured polybutadiene rubber composition and having a diameter of 1.25 inches or less and a center Shore C hardness (H.sub.center) of 50 or less; and an outer core layer consisting of a thermoplastic composition Tc as defined herein and having a thickness of 0.400 inches or greater and an outer surface Shore C hardness (H.sub.outer surface) of 70 or greater, wherein H.sub.outer surface>H.sub.center, and H.sub.outer surface−H.sub.center≧40. The peroxide cured polybutadiene rubber composition may comprise a reaction product of polybutadiene and a sufficient amount of peroxide to form the solid inner layer having the center Shore C hardness (H.sub.center) of 50 or less. In one embodiment, 100 phr polybutadiene and from about 0.05 phr to about 3.0 phr of peroxide are mixed with at least one of 5 phr or less of a metal oxide; 5 phr or less of a metal coagent; or 5 phr or less of a metal carbonate. Alternatively, the solid inner core layer has a diameter of 1.10 inches or less or less than 1.0 inches.