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).

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 80 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. The protection layer has an outer diameter of 3 to 16 mm, the relaxation layer has an outer diameter of 21 mm or less, and the core has a thickness of 8 mm or more.

Multi-layered golf balls containing a three-layered cover assembly are provided. For example, a cover assembly having an inner cover, intermediate cover, and outer cover layer may be prepared. At least one of the cover layers is formed from a thermoplastic composition that preferably comprises: a) thermoplastic non-acid polymer, and b) plasticizer. A fatty acid ester such as ethyl oleate is preferably used as the plasticizer. Suitable non-acid polymers include, for example, polyesters, polyamides, polyolefins, and polyurethanes. The cover assembly has good impact durability and helps provide the ball with relatively high resiliency at given compressions.

Golf balls having an inner core made of a foamed composition are provided. The core assembly preferably includes a foam inner core (center) and surrounding outer core layer. A cross-linked thermoplastic, preferably an ethylene acid copolymer ionomer, is used to form the foam composition. The core layers have different hardness gradients and specific gravity values. The ethylene acid copolymer is reacted with a metallic acrylate salt and peroxide free-radical initiator to form the cross-linked polymer. The foamed, cross-linked composition helps provide the inner core with good resiliency, thermal stability, and durability. Non-foamed thermoplastics or thermosets such as polybutadiene rubber may be used to form the outer core layer. The ball further includes a cover that may be multi-layered.

In a golf ball having a two-layer core consisting of an inner core layer and an outer core layer and a cover of one or more layer, the inner core layer and outer core layer are each formed of a rubber composition made up primarily of a base rubber, the inner core layer has a diameter of not more than 30 mm; and the core has specific hardness ratios (JIS-C hardness/Shore D hardness) at specific points on the cross-section thereof. This golf ball has a reduced spin rate on full shots with a driver and middle irons, thus imparting to an excellent flight performance, and moreover has a good controllability in the short game on approach shots, making it ideal as a golf ball for professional golfers and mid- and high-level amateur golfers.

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-layered golf balls having at least one layer made of a foamed silicone composition are provided. Multi-layered golf balls having at least one layer made of non-foamed silicone elastomer composition also are provided. For example, three-piece, four-piece, and five-piece golf balls containing different core and cover structures can be made. The foamed silicones have good thermal stability and durability without sacrificing resiliency. The non-foamed silicone elastomers have high elongation, tensile strength, chemical/fluid-resistance, and weatherability properties. These compositions can be used to form any layer, for example, core, intermediate, or cover, in the golf ball.

Multi-layered golf balls having at least one layer made from silicone (polysiloxane) elastomers; silicone (polysiloxane) elastomer/polyurethane blends; polycarbonate-polysiloxane blends and copolymers; and polycarbonate-polysiloxane/polyurethane blends are provided. For example, three-piece, four-piece, and five-piece golf balls containing different core and cover structures can be made. The polysiloxane compositions have good thermal stability and durability without sacrificing resiliency. The polysiloxane compositions also have high elongation, tensile strength, chemical/fluid-resistance, and weatherability properties. These compositions can be used to form any layer, for example, core, intermediate, or cover, in the golf ball.

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).

Golf balls having cores with increased hardness gradients are provided. The cores have an increased positive hardness gradient (or a hard-to-soft hardness) where the outer surface of the core is harder than the center. The increased positive hardness gradient can be achieved by introducing a water-releasing agent into the core rubber formulation during the curing process. The resulting golf balls have reduced spin and sufficient impact durability.