In a multi-piece solid golf ball made up of, successively, a core, an intermediate layer and a cover having numerous dimples on the surface thereof, the intermediate layer is formed of a resin material and the cover is formed of a urethane resin material, each having a specific respective Shore D hardness. The ball has a specific (intermediate layer thickness)/(core diameter) value and a specific (cover thickness)/(core diameter) value, and the core has a specific deflection and has a specific hardness profile from a center to a surface thereof. This golf ball provides an increased distance and has both a soft feel when played and a high durability to repeated impact.

Golf balls comprising a multi-layer core and a cover are disclosed. The multi-layer core comprises a center, an intermediate core layer, and an outer core layer. At least one layer of the multi-layer core is a high specific gravity layer.

A golf ball comprising a core composed of a fully neutralized polymer material is disclosed herein. The golf ball also preferably has multiple mantle layers and a cover.

In a golf ball having a core, an intermediate layer and a cover, the core is formed of a rubber composition and the intermediate layer and the cover are each formed of a resin composition. The core, the intermediate layer-encased sphere and the ball have respective initial velocities which together satisfy the following two conditions:

(initial velocity of ball)<(initial velocity of intermediate layer-encased sphere),

0.65(initial velocity of intermediate layer-encased sphere)(initial velocity of core)1.15 m/s.

Also, letting C and B be the respective deflections in millimeters of the core and the ball when compressed under a specific load, the value of CB is 1.20 mm or more. This golf ball can achieve a superior distance on shots with a utility club and on shots with irons, and exhibits a good durability to repeated impact and a good controllability in the short game.

In a golf ball having a core, an envelope layer, an intermediate layer and a cover, the core is formed of a rubber composition and the envelope layer, the intermediate layer and the cover are each formed of a resin composition. The core, the envelope layer-encased sphere, the intermediate layer-encased sphere and the ball have respective initial velocities which together satisfy the following three conditions: (initial velocity of ball)<(initial velocity of intermediate layer-encased sphere), (initial velocity of intermediate layer-encased sphere)(initial velocity of envelope layer-encased sphere)0.60 m/s, and 0.50(initial velocity of envelope layer-encased sphere)(initial velocity of core)1.08 m/s.
This golf ball can achieve a superior distance on shots with a utility club and with irons, and exhibits a good durability to repeated impact, a good controllability in the short game and a good feel at impact.

Multi-piece golf balls having a solid core made of a foamed composition and a cover are provided. Preferably, the core is dual-layered having has a foam inner core (center) and surrounding thermoset or thermoplastic outer core layer. Preferably, a polyurethane foam composition containing mineral filler particulate, for example, nanoclay particles, is used to form the foam center. The concentration of clay particulate is preferably in a range of 0.1 to 60% by weight. The surrounding outer core layer may be made from non-foamed or foamed compositions. For example, polybutadiene rubber or highly neutralized olefin acid copolymers may be used in the outer core layer. The core layers have different hardness gradients and specific gravity values.

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 plasticizers 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.

Golf balls comprising a multi-layer core and a cover are disclosed. The multi-layer core comprises at least three layers, including at least one thermoset layer and at least one thermoplastic layer. The innermost core layer is relatively small, having a diameter of from 0.50 inches to 1.30 inches.

Golf balls having a multi-layered core made of a foamed composition are provided. The core preferably has a foam inner core (center) and surrounding thermoset or thermoplastic outer core layer. Preferably, a polyurethane foam composition is used to form the foam center. The foam inner core preferably includes a fully-foamed center region and a partially or completely-collapsed foam outer region. The hardness of the fully-foamed region is different than the hardness of the collapsed foam region. Non-foamed thermoset or thermoplastic materials such as polybutadiene rubbers or ethylene acid copolymer ionomer may be used to form the outer core layer. The ball further includes a cover that may be multi-layered. The foam cores have good resiliency.

Multi-layered 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 core layers have different hardness and specific gravity levels. The specific gravity (density) of the foam inner core is preferably less than the density of the outer core layer. The core assembly preferably has a positive hardness gradient extending across the entire assembly. The core structure and resulting ball have relatively good resiliency.