Multi-piece golf balls containing a multi-layered core structure having layers with different hardness gradients and specific gravities are provided. The core structure includes a small, heavy inner core (center) having a relatively high specific gravity with metal material preferably dispersed in a first thermoset composition. The intermediate core layer is preferably formed from a thermoplastic composition such as an ethylene acid copolymer ionomer resin; and the outer core layer is preferably formed from a second thermoset composition. The resulting ball has high resiliency and good spin control.

A golf ball comprising layers that have from 0.05% to 70% by weight of a radio-opaque filler, and wherein the concentration of the radio-opaque filler is measurably different in each layer is disclosed herein. The radio-opaque filler is preferably a compound based on barium, bismuth, tungsten, iodine, or reduced iron.

In a golf ball having a core, envelope layer, intermediate layer and cover, the (core diameter)/(ball diameter) value falls within a particular range, the core has a specific hardness profile, the intermediate layer is formed primarily of an ionomer resin material including a high-acid ionomer resin, and the Shore C hardness relationships among the core center and surface hardnesses and the surface hardnesses of the envelope layer-encased sphere, intermediate layer-encased sphere and ball satisfy the following conditions: (1) core surface hardness<surface hardness of envelope layer-encased sphere<surface hardness of intermediate layer-encased sphere>ball surface hardness, (2) (surface hardness of envelope layer-encased sphere)−(core center hardness)≥28.

Also, the intermediate layer and cover have respective thicknesses which satisfy the condition: (3) cover thickness<intermediate layer thickness.

This ball enables mid-level and skilled amateur golfers to achieve superior distances on driver shots and on iron shots, and moreover has a soil yet good feel at impact.

Multi-layer golf balls having a hard, high compression center, a relatively soft intermediate layer, and a stiff outer cover layer, are provided. The outer surface hardness of the intermediate layer is less than that of both the center and the outer cover layer.

A cured elastomer golf ball component is made by heating an elastomer compound containing an ethylenically unsaturated elastomer, an ethylenically unsaturated monomer, and first and second free radical initiators to a first crosslinking temperature T.sub.1 in a compression mold and partially crosslinking the elastomer, then heating to a second crosslinking temperature T.sub.2 and curing the elastomer component of the golf ball. Either: (i) the first initiator has a half-life of about 0.2-5 minutes at T.sub.1, the second initiator has a half-life of about 0.2-5 minutes at T.sub.2, and T.sub.2 is higher T.sub.1 by at least about 30° C.; or (ii) the second initiator's one-minute half-life temperature is at least about 30° C. higher than the first initiator's one-minute half-life temperature, T.sub.1 is within about 20° C. of the first initiator's one-minute half-life temperature, and T.sub.2 is within about 20° C. of the second initiator's one-minute half-life temperature.

A golf ball comprising a core and a cover, wherein the core consists of: a solid inner core layer formed from an unfoamed thermoplastic composition and having a diameter of 1.10 inch or less and a center Shore C hardness (H.sub.center) of 50 or less, one or more optional intermediate core layers, and an outer core layer formed from an unfoamed thermoset composition and having a thickness of 0.200 inches or greater and an outer surface Shore C hardness (H.sub.outer surface) of 70 or greater, wherein H.sub.outer surface>H.sub.center, and H.sub.outer surface−H.sub.center≧40.

A golf ball with embedded electronics to allow proximity to be tracked and to monitor golfer performance is disclosed. The golf ball comprises a processor connected to an accelerometer, communications circuitry, a spin detector, and memory, wherein the processor stores accelerometer data from the accelerometer and rotation data regarding rotation of the spin detector in the memory. The processor converts the data regarding the rotation of the spin detector into a rotation speed and a rotation direction, said rotation speed determined by a frequency of the data, and said rotation direction determined by a magnitude of the data. The communications circuitry is configured to communicate the accelerometer data, the rotation direction, and the rotation speed to a central interrogator for analysis of a golfer's performance.

A golf ball includes a relatively large polymer core and has a soft ball compression. The polymer is, in the illustrated embodiments, a highly neutralized acid polymer. The golf ball may, optionally, include an outer core made of a different material, such as a thermoset polybutadiene rubber. The golf ball may, optionally, include a mantle layer made of an ionomer material. The inner core having a diameter of between 24 mm and 40 mm, and in some designs, between 28 mm and 32 mm, yields increased iron initial velocity and lower iron spin while maintaining driver performance.

A golf ball resin composition contains a base resin for which, in dynamic viscoelasticity measurement, the storage modulus of the base resin measured at 23° C., 15 Hz and 1.0% strain, and tan δ determined under the same conditions, satisfy specific values; and for which the storage modulus of the base resin measured at 23° C., 15 Hz and 10% strain, and tan δ determined under the same conditions, satisfy specific values. By using this resin composition as a golf ball cover material, the force delivered to the ball while the ball and the clubface are in contact from impact to follow-through is more easily felt, facilitating distance control of the ball. Controllability with a short iron such as a sand wedge around the green is also excellent.

Multi-piece golf balls having a solid core made of a foamed silicone composition and a cover are provided. For example, three-piece, four-piece, and five-piece golf balls containing different core structures can be made. Preferably, a dual-core having has a silicone foam inner core (center) and surrounding silicone foam outer core layer is made. The core layers can have different hardness gradients. The silicone foam center and outer core layer have good thermal stability and durability and provide the ball with good resiliency.