Multi-layered golf balls containing a dual-core structure are provided. The core structure includes an inner core (center) made from a foam or metal-containing composition, or it has a hollow shell construction, and the outer core layer is made of a thermoplastic composition. Preferably, the thermoplastic composition 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 core assembly preferably has a positive hardness gradient extending across the entire assembly. The core structure and resulting ball have relatively good resiliency at given compressions.

In a multi-piece solid golf ball having a core, an envelope layer, an intermediate layer, and a cover with a plurality of dimples thereon, the core is a two-layer core consisting of an inner core layer and an outer core layer each formed primarily of a base rubber, the envelope layer, the intermediate layer and the cover layer are each composed of at least one layer and formed primarily of a synthetic resin material, and the initial velocities and surface hardnesses of the core, the envelope layer-encased sphere and the intermediate layer-encased sphere are designed within specific ranges. This golf ball satisfies at a very high level the flight and control performances expected for use by professional golfers and skilled amateurs, has the ability to move forward on a straight path particularly on full shots, and also has an excellent scuff resistance.

Disclosed herein are two-layer and three-layer, low compression golf balls including a low compression single- or dual-layer rubber core and a single cover layer.

Multi-layer golf balls comprising a center, intermediate layer, and cover are disclosed. The center is formed from a highly-neutralized acid copolymer composition.

Golf balls comprising a multi-layer core and a cover are disclosed. The multi-layer core comprises a layer formed from a highly neutralized polymer composition, a layer formed from an additional thermoplastic composition, and an outermost layer formed from a thermoset rubber.

A multi-layer golf ball includes a core formed from an ionomer, an intermediate layer surrounding the core, and a cover surrounding the intermediate layer. The core has a material hardness measured on the JIS-C scale of from about 34 to about 70, and has an outer surface that includes a plurality of land portions aligned on a common sphere, and a plurality of grooves separating the respective land portions and extending radially inward from the sphere. The plurality of grooves includes both a first set of grooves, and a second set of grooves that are perpendicular to each other. The intermediate layer is formed from a rubber material and has a radial thickness measured from the common sphere of from about 4.0 mm to about 9.0 mm. Additionally, the core has a 10-130 kg compression deformation of from about 3.5 to about 5.5 mm.

Golf balls having a very high positive gradient multilayer core are provided. The multilayer core includes an outer core layer and a very soft, low compression inner core layer. The inner core layer is formed from an unfoamed composition and has a center hardness that is at least 40 Shore C points less than the outer surface hardness of the outer core layer.

In a multi-piece solid golf ball having a rubber two-layer core consisting of an inner layer and an outer layer, a cover, and at least one intermediate layer therebetween, the inner core layer has a diameter of at least 30 mm, the difference in JIS-C hardness between the center of the inner core layer and the surface of the outer core layer is at least 25, the ball satisfies the relationship A/B1.5, where A and B are the deflections of, respectively, the inner core layer and the two-layer core when compressed under specific loading conditions, and the intermediate layer has a higher material hardness than the cover. This ball enables mid- to high-level golfers both to achieve even longer distances and to maintain the spin performance on approach shots at a high level.

Golf balls comprising a multi-layer core and a cover are disclosed. The multi-layer core comprises a layer formed from a highly neutralized polymer composition and a layer formed from a thermoset rubber.

Multi-piece golf balls having at least one layer made from a polyamide non-ionomeric composition are provided. The polyamide composition consists essentially of about 40 to about 99% by weight polyamide; about 1 to about 60% by weight of an acid anhydride-modified polyolefin; and about 1 to about 60% of a fatty acid additive selected from the group consisting of fatty acid salts, fatty acid amides, and mixtures thereof. The ball includes a core, preferably a dual core construction; and a cover of at least one layer. In another preferred construction, a multi-layered core containing an inner, intermediate, and outer core layer is made. For example, the intermediate core layer may be made of a rubber composition; and each of the inner core and outer core layers may be made of the polyamide composition. The resulting ball has high resiliency along with a soft feel.