Compositions including a resiliency additive and golf ball components made from such compositions having a tailored Coefficient of Restitution are disclosed. The type and concentration of the constituents in the composition, including the resiliency additive, affects the Coefficient of Restitution of components made from the composition and, thus, can be used to produce a golf ball having desirable performance characteristics.

The invention provides a golf ball having a core and a cover of one layer or a plurality of layers, wherein the core is formed of a material molded under heat from a rubber composition containing (A) a base rubber, (B) an organic peroxide, and (C) water and/or a metal monocarboxylate, and has a hysteresis loss of 50% or less when compressed at a load cell speed of 500 mm/min and under a constant load of 5,000 N.

Multi-piece golf balls containing a dual-core structure are provided. The core structure includes an inner core (center) comprising a foam composition, preferably foamed polyurethane. The outer core layer is preferably formed from a non-foamed thermoset composition such as polybutadiene rubber. The inner and outer core layers can have different hardness gradients. Preferably, the specific gravity (density) of the foam inner core is less than the density of the outer core layer. The ball further includes a cover of at least one layer and may include at least one casing layer. The core structure and resulting ball have relatively good resiliency.

A golf ball includes: a radio frequency identification (RFID) tag including an IC chip and an antenna; a protection layer surrounding the outer periphery of the RFID tag; a relaxation layer surrounding the outer periphery of the protection layer; a core surrounding the outer periphery of the relaxation layer; and a cover surrounding the outer periphery of the core. The curing temperature of the protection layer is 60 C. or less, and the protection layer is formed with a material having a hardness of Shore D 60 or more. The relaxation layer is formed with a thermoplastic elastomer-based material having a hardness with a difference from a hardness of a surface of the core on a side contacting the relaxation layer of Shore D 20 or less.

Multi-layered golf balls containing a two or three-layered cover assembly are provided. In one embodiment, the cover assembly includes a relatively hard inner cover and relatively soft outer cover. Alternatively, the cover assembly may include a relatively soft inner cover with a relatively hard outer cover. Three-layered covers comprising an inner cover, intermediate cover, and outer cover layer also may be prepared. Preferably, at least one of the layers is formed from a thermoplastic composition that preferably comprises: a) ethylene acid copolymer, b) plasticizer, and c) cation source. A fatty acid ester such as ethyl oleate is preferably used as the plasticizer. The cover assembly has good impact durability and helps provide the ball with relatively high resiliency at given compressions.

A colored golf ball has improved luxurious appearance without impairing its visibility. The colored golf ball of the present invention includes a core; a cover placed around the core having dimples formed on its surface; and a coating layer placed on top of the cover, in which the coating layer includes a polymer matrix having a bright material dispersed therein, and an L.sub.0 value, which represents an L value in the Lab color system of the colored golf ball before being covered with the coating layer, is 55 or less, and the difference L between the L.sub.0 value and an L.sub.1 value, which represents an L value in the Lab color system of the colored golf ball after being covered with the coating layer, is 5 or more.

The invention provides a golf ball having a core and a cover of one layer or a plurality of layers, the core being formed of a material molded under heat from a rubber composition containing: (A) a base rubber, (B) an organic peroxide, and (C) water and/or a metal monocarboxylate. The core has a hardness profile which satisfies specific relationships between the JIS-C hardness at the core center (Cc), the JIS-C hardness at a position 10 mm from the core center (C10) and the JIS-C hardness at the core surface (Cs).

An object of the present invention is to provide a golf ball having an excellent initial velocity when being hit at a head speed of 50 m/sec and an improved initial velocity when being hit at a head speed of 40 m/sec. The present invention provides a golf ball comprising a spherical core and a cover covering the spherical core, wherein the golf ball has a rebound equivalence energy ratio (R.sub.40) ranging from 65.50% to 99.0% at a deformation amount of 7%, and a rebound equivalence energy ratio (R.sub.50) ranging from 20.0% to 70.0% at a deformation amount of 19%, in a compression test (measurement temperature: 70 C., compression speed: 30 mm/min) applying a load to the golf ball along a radial direction of the golf ball.

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.

Golf ball comprising layer(s) comprised of plasticized neutralized acid polymer composition consisting of mixture of: (a) low molecular weight acid-containing wax(es); (b) non-acid-polymer(s) including at least one low molecular weight non-acid wax such as high density oxidized polyethylene homopolymers; ethylene maleic anhydride copolymers; polypropylene maleic anhydride copolymers; polypropylene homopolymers; ethylene-vinyl acetate copolymers; high density oxidized homopolymers; oxidized copolymers; polyethylene micronized waxes; polytetrafluoroethylene micronized waxes; emulsifiable low molecular weight non-acid waxes; non-emulsifiable low molecular weight non-acid waxes; and/or chemically modified low molecular weight non-acid waxes; (c) organic acid(s) or salt thereof; and (d) plasticizer(s). Molecular weight of each low molecular weight acid-containing wax is about 500 to 7000, or up to 30,000. Interactions between components (a), (b), (c) and (d) advantageously produce layer of ionomeric material having heat stability, processability, and well-retained durability, adhesion, CoR, compression and softer feel without need for blending high and low molecular weight acid-containing polymer(s).