Multi-layered golf balls having an inner core with a relatively large diameter are provided. In one embodiment, the golf ball comprises an inner core, outer core, and cover. The inner core comprises a thermoset or thermoplastic composition. For example, a blend of polybutadiene rubbers can be used to form the inner core. The outer core layer is relatively thin and comprises a thermoset or thermoplastic composition. The dimensions and compressions of the core layers have specific relationships referred to as the Core Profile. The golf ball further comprises a cover having at least one layer. Ethylene acid copolymer ionomers and polyurethanes, particularly thermoplastic polyurethane, can be used to form the cover.

Golf ball comprising at least one layer that is comprised of a cured elastomeric composition comprising a mixture of an elastomeric composition and an organic peroxide-based curing composition; wherein the mixture at least partially contacts oxygen during curing.

A method for forming a golf ball with a graphene core disclosed herein. The method includes mixing a graphene masterbatch material with a polybutadiene material to form a core mixture, wherein the graphene masterbatch material comprises graphene in an amount from 0.1 to 80.0 weight percent of the graphene masterbatch material mixed with a carrier polymer in an amount from 99.9 to 20 weight percent of the graphene masterbatch material.

Golf ball comprising a core and a cover, wherein the core includes between 2 and 20 smaller spheres that are surrounded by a second core composition having at least one different physical property than the composition(s) forming the smaller spheres. The smaller spheres can be entirely surrounded by the second core composition; or, at least two smaller adjacent spheres may each be partially surrounded by the second core composition while also being in partial contact with each other.

An object of the present disclosure is to provide a golf ball having an increased spin rate when being hit with an 8-iron while suppressing rise in a spin rate when being hit with a driver. The present disclosure provides a golf ball comprising a spherical core having an inner core and an outer core, and a cover positioned outside the spherical core, wherein A×a is 12,200 or less and B×b is 20,400 or more, where “a” represents an average hardness (Shore C) of a hardness (H2.5) at a point of 2.5 mm from a center of the spherical core and a hardness (H5) at a point of 5 mm from the center of the spherical core, “b” represents an average hardness (Shore C) of a hardness (H7.5) at a point of 7.5 mm from the center of the spherical core and a hardness (H9) at a point of 9 mm from the center of the spherical core, “A” represents an impulse difference (kN.Math..Math.s) between a back spin impulse and a top spin impulse measured using a contact force tester under a condition corresponding to a condition when the golf ball is hit with a driver, and “B” represents an impulse difference (kN.Math..Math.s) between a back spin impulse and a top spin impulse measured using a contact force tester under a condition corresponding to a condition when the golf ball is hit with an 8-iron.

A method for forming a golf ball core with a nanofiller masterbatch is disclosed herein. The method includes mixing the nanofiller masterbatch, a graphene masterbatch material with other materials to form a core mixture, wherein the masterbatch preferably comprises 1-80% by weight of nanofillers and 20-99% by weight of a carrier polymer.

A golf ball with improved durability is disclosed herein. The golf ball has a mantle layer comprising a blend of ionomers and methyl methacrylate, butadiene, styrene (MBS) with a weight percentage of MBS ranging from 5 to 15 weight percent of the mantle layer.

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, 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.

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<envelope layer-encased sphere surface hardness<intermediate layer-encased sphere surface hardness>ball surface hardness,

(envelope layer-encased sphere surface hardness)−(core center hardness)≥28, and

(intermediate layer-encased sphere surface hardness)−(core center hardness)≥39.

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

cover thickness<intermediate layer thickness≤envelope layer thickness.

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