A golf ball with a core comprising polybutadiene and graphene is disclosed herein. The golf ball has a single core comprising polybutadiene and graphene. Alternatively, the golf ball has a dual core with an inner core comprising polybutadiene and graphene. Alternatively, the golf ball has a dual core with an outer core comprising polybutadiene and graphene.

A golf ball according to the present invention includes: a module including an electronic circuit and its power source; a protective layer that surrounds an outer periphery of the module and is formed from a material having a Shore D hardness of at least 60; a core that surrounds an outer periphery of the protective layer; and a cover that surrounds an outer periphery of the core. A weight may be arranged on a surface of the protective layer. A difference between a value MOImax of the moment of inertia in a direction in which the moment of inertia of the golf ball is maximum and a value MOImin of the moment of inertia in a direction in which the moment of inertia of the golf ball is minimum is at most 1.0 g.Math.cm.sup.2.

In a golf ball having a core of one or more layer and a cover of one or more layer encasing the core, the core has a deflection when compressed under a specific load of at least 3.8 mm; at least an innermost portion of the core has a specific difference between maximum and minimum values in cross-sectional hardnesses (JIS-C) from a center to a surface thereof; and the center core is formed of a rubber composition that includes (a) a base rubber, (b) an α,β-unsaturated carboxylic acid and/or metal salt thereof, (c) a diacyl peroxide and/or a peroxyester, and (d) a dialkyl peroxide and/or a peroxyketal. The golf ball has a low spin rate on driver shots by low head speed golfers, and thus achieves an improved distance, while minimizing any decrease in durability.

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, 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:

core surface hardness<surface hardness of envelope layer-encased sphere<surface hardness of intermediate layer-encased sphere>ball surface hardness,  (1)

(surface hardness of envelope layer-encased sphere)−(core center hardness)≥28.  (2)

Also, the envelope layer, intermediate layer and cover have respective thicknesses which satisfy the condition:

cover thickness<intermediate layer thickness envelope layer thickness.  (3)

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

A golf ball comprising: (a) a core; (b) at least one mantle layer adjacent to the core; (c) an inner cover layer adjacent to the mantle layer; and (d) an outer cover layer adjacent to the inner cover layer, wherein the inner cover layer has a material Shore D hardness that is at least 3 less than the material Shore D hardness of the outer cover layer, and the inner cover layer has a thickness of less than 0.050 in.

A golf ball comprising: (a) a core; (b) at least one mantle layer adjacent to the core; (c) an inner cover layer adjacent to the mantle layer; and (d) an outer cover layer adjacent to the inner cover layer, wherein the inner cover layer has a material Shore D hardness that is at least 3 less than the material Shore D hardness of the outer cover layer, and the inner cover layer has a thickness of less than 0.050 in.

A golf ball 2 includes a main body 4 and a paint layer 6 positioned outside the main body 4. The main body 4 includes a spherical core 8, a mid layer 10 positioned outside the core 8, and a cover 12 positioned outside the mid layer 10. An indentation depth, measured when the paint layer 6 in a cross-section along a plane passing through a central point of the golf ball 2 is pressed by a force of 30 mgf in a direction perpendicular to the cross-section, is not less than 300 nm and not greater than 3000 nm. The paint layer 6 preferably has a thickness of not less than 5 μm and not greater than 50 μm.

Golf balls having a single or dual-layered solid core are provided. In one embodiment, the golf ball has dimensions and properties that do not conform to the rules of the United States Golf Association (USGA). For example, the ball weight; ball size; ball spherical symmetry; ball initial velocity; and/or ball overall distance may fall outside of the USGA standards. The dual-layered core can have an inner core comprising a thermoplastic composition and surrounding outer core comprising a thermoset composition. In another embodiment, the dual-layered core has an inner core comprising a thermoplastic composition and outer core comprising a thermoset composition. The thermoplastic composition preferably comprises an ethylene acid copolymer ionomer and plasticizer. The thermoset composition preferably comprises polybutadiene rubber. The ball further includes a cover of at least one layer.

A golf ball with a core comprising polybutadiene and graphene with an embedded IC is disclosed herein. The golf ball preferably has a single core comprising polybutadiene and graphene. Alternatively, the golf ball has a dual core with an inner core comprising polybutadiene and graphene. Alternatively, the golf ball has a dual core with an outer core comprising polybutadiene and graphene.

In a multi-piece solid golf ball having a core, an envelope layer, an intermediate layer and a cover, the core is formed of one or more layer of a rubber composition; the envelope layer, intermediate layer and cover are each formed of a single layer of resin material; the hardness relationship among the layers satisfies the following two conditions:

material hardness of cover>material hardness of intermediate layer, and

material hardness of envelope layer≥surface hardness of core;

the ball additionally satisfies the condition: envelope layer thickness (mm)×envelope layer material hardness (Shore D hardness) cover thickness (mm)×cover material hardness (Shore D hardness); and the core and ball have optimized deflections when subjected to a specific loading. This ball serves as a distance ball which enables a superior distance to be achieved on full shots with a driver and with irons.