Golf ball multi-layered core sub-assemblies and the resulting golf balls are provided. The core structure includes a foam inner core (center); and intermediate and outer core layers. Foamed polyurethane is preferably used to make the inner core. The intermediate and outer core layers are preferably made from non-foamed thermoplastic compositions such as ethylene acid copolymer ionomer. In an alternative version, the intermediate core layer may be made of a thermoset rubber such as polybutadiene. The core layers have different hardness and specific gravity levels. The core structure and resulting ball have relatively good resiliency.

Multi-piece golf balls having a multi-layered solid core and multi-layered cover are provided.

A golf ball includes a core having an outer surface and a geometric center. The core is formed from a substantially homogenous rubber composition. An ionomeric inner cover layer is formed about the core and has a material hardness of about 60 Shore D or greater. The golf ball includes an outer cover layer formed from a polyurea or a polyurethane and having a material hardness of about 60 Shore D or less. The outer surface of the core has a trans content of about 12% or less and a hardness of about 71 to 88 Shore C. The geometric center of the core has a trans content of about 10% or less and a hardness of about 60 to 80 Shore C. The core has an outer surface hardness greater than a geometric center hardness by about 5 to 19 Shore C to define a positive hardness gradient.

A golf ball is provided which suppresses twisting due to external forces while maintaining sufficient deflection at the time of impact, reduces the spin rate without lowering ball rebound, and is thus able to effectively increase the distance traveled by the ball, particularly on shots with a driver. In the golf ball, which includes a core and a cover, the core has a core body made of a first polybutadiene rubber and having a surface with a plurality of groves or holes thereon, which grooves or holes are filled with a second polybutadiene rubber of a differing composition from the first polybutadiene rubber. The polybutadiene rubber-filled groove portions or hole portions have a higher surface hardness than the core body.

A golf ball comprising a core and a cover layer, wherein at least one of the core or cover layer comprises a plasticized polyurethane composition comprising at least one polyurethane and at least one plasticizer.

An object of the present invention is to provide a golf ball traveling a great distance on driver shots and on iron shots. The present invention provides a golf ball comprising a spherical core including an inner layer and an outer layer, and a cover, wherein a difference (H.sub.X+1−H.sub.X−1) between a hardness (H.sub.X+1) at a point outwardly away in a radial direction from a boundary between the inner layer and the outer layer of the spherical core by 1 mm and a hardness (H.sub.X−1) at a point inwardly away in the radial direction from the boundary between the inner layer and the outer layer of the spherical core by 1 mm is 0 or more in Shore C hardness, a surface hardness (H.sub.X+Y) of the spherical core is more than 65 in Shore C hardness, an angle α of a hardness gradient of the inner layer is 0° or more, a difference (α−β) between the angle α and an angle β of a hardness gradient of the outer layer is 0° or more, a thickness of the cover is 3 mm or less, a difference (Hc−H.sub.x+y) between a hardness (Hc) of the cover and the surface hardness (H.sub.X+Y) of the spherical core is 2 or more in Shore C hardness, and the cover has a highest hardness among the constituent members of the golf ball.

The present invention is directed to a golf ball having a cover in which the dimples have two distinct hardness regions. The cover of the present invention is formed from a castable formulation including at least one prepolymer that incorporates some degree of unsaturation in the backbone of the polymer, at least one curative, and at least one free radical initiator. The present invention also explores the methods of making such golf balls. The methods of the present invention allow for the production of a golf ball dimple with two distinct hardnesses to be formed using a single castable formulation.

A golf ball a core, one or more intermediate layers, and one or more cover layers. The core may comprise an inner portion and an outer portion. One or more layers of the golf ball may be formed by the application of ultrasonic welding on two half shells to form. One or more of the layers may be formed by a number of different chemical compositions, and may have varying thicknesses, hardnesses, coefficients of restitution, and PGA compression. The golf ball itself may have varying coefficient of restitution and PGA compression, depending on the layers.

Golf ball 2 of the present invention has core 4, cover 10 situated on the external side of the core 4, and paint layer 16 provided to cover this cover 10. The base polymer of the cover 10 is a urethane resin. The base polymer of the paint layer 16 is a urethane resin. The cover 10 has a thickness Tc of 0.1 mm or greater and 0.7 mm or less. The paint layer 16 has a thickness Tp (mm) of 0.015 mm or greater and 0.040 mm or less. The ratio (Tp/Tc) is 0.021 or greater and 0.40 or less. Preferably, the paint layer 16 is formed with two or more layers 18 and 20. Preferably, the base polymer of the paint layer 16 is a two-pack type urethane resin or a two-pack type epoxy resin.

Multi-piece golf balls having a multi-layered solid core and multi-layered cover are provided.