An object of the present invention is to provide a golf ball resin composition having a high resilience, flexibility and high fluidity. The present invention provides a golf ball resin composition having a bending stiffness (M.sub.21-30) ranging from 600 kgf/cm.sup.2 to 5,000 kgf/cm.sup.2 within a bending angle from 21 to 30, a rebound resilience (R) of 50% or more, a slab hardness (Shore D) ranging from 40 to 65, a melt flow rate (190 C., 2.16 kgf) of 1.0 g/10 min or more, and a resilience index value ((M.sub.21-30).sup.0.5(R/100).sup.3) of 8.5 or more.

The invention provides a golf ball having a core and a cover of one or more layer encasing the core, wherein the core is formed of a rubber composition that includes a base rubber, a co-crosslinking agent and an organic peroxide. The core has a center portion and a surface portion that are unfoamed regions, and has an intermediate portion that contains a foamed region. A method of manufacturing such a golf ball is also provided.

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.

An object of the present invention is to provide a golf ball having excellent flying performance on driver shots. The present invention provides a golf ball having a spherical core and at least one cover layer covering the spherical core, wherein the spherical core is formed from a rubber composition containing: (a) a base rubber, (b) an ,-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, (c) a crosslinking initiator, (d) an unsaturated fatty acid and/or a metal salt thereof (excluding an ,-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof), and (e) a saturated fatty acid and/or a metal salt thereof, provided that the rubber composition further contains (f) a metal compound in the case of containing only (b) the ,-unsaturated carboxylic acid having 3 to 8 carbon atoms as the co-crosslinking agent.

An object with a tactile outer layer includes, for example, a ball having an outer surface and a series of protrusions or spikes on the outer surface. The protrusion each appear as a tear-dropped shape mass that includes a base having a relatively flat bottom adhered to the outer surface of the ball and a narrow tip and/or curved tail extending away from the outer surface.

Manufacturing can be performed by mounting the object and utilizing injection arms that deposit elastomer globules on the object. The globules are deposited by pressure through a reservoir in the injection arm and the injection arms are then withdrawn to product the tail shape.

A spiked ball includes an inflatable ball having an outer surface and a series of protrusions on the outer surface. The protrusion each appear as a tear-dropped shape mass that includes a base having a relatively flat bottom adhered to the outer surface and a narrow tip extending away from the outer surface. The narrow tip may also appear as a curved tale.

The spikes provide a unique tactile feel and a surface for gripping that is different than other balls. The spikes also cause the ball to contact or grab the ground to create a unique bounce.

Multi-piece golf balls containing a dual-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 having a relatively low specific gravity. The core structure may have different hardness gradients. In one preferred embodiment, the inner core and outer core each 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 outer core layer preferably is formed from a thermoset composition such as polybutadiene rubber. The resulting ball has high resiliency and good spin control.

Methods of creating golf products with complex structures that would be difficult, impossible, or cost prohibitive to produce, such as lattice structures, beam structures, and complex surface-based structures, and golf products that are created using those methods, are described herein. The structures described herein may be made from metal, non-metal materials, or combinations thereof, and may have one or more portions that are made from transparent or translucent materials.

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.

A molded game ball comprises an outer cover or surface having a mold line that mimics the seam of a conventional baseball or softball. The outer cover or surface may additionally include a stitch pattern that mimics the stitching of a conventional baseball or softball.