An object of the present invention is to provide a cured product of a golf ball rubber composition for constituting a golf ball having excellent shot feeling on both driver shots and approach shots. The present invention provides a cured product of a golf ball rubber composition, wherein the golf ball rubber composition contains (a) a base rubber, (b) an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, and (c) a crosslinking initiator, and a product (hardness×(tan δ.sub.−80−tan δ.sub.0)) obtained by multiplying a slab hardness of the cured product of the golf ball rubber composition in Shore C hardness by a difference (tan δ.sub.−80−tan δ.sub.0) between a loss tangent of the cured product of the golf ball rubber composition at −80° C. (tan δ.sub.−80) and a loss tangent of the cured product of the golf ball rubber composition at 0° C. (tan δ.sub.0) is 28.0 or more.

An object of the present invention is to provide a golf ball having excellent resilience. The present invention provides a golf ball comprising a spherical core and at least one cover covering the spherical core, wherein the spherical core is formed from a rubber composition containing (a) a base rubber, and (b) a co-crosslinking agent containing (b1) a carboxylic acid represented by a structural formula (1) and/or a metal salt thereof. ##STR00001##
[In the formula (1), A.sup.1 to A.sup.4 each independently represents a nitrogen atom or a carbon atom. X.sup.1 represents a single bond or a divalent organic group. R.sup.1 represents a hydrogen atom or a monovalent organic group. It is noted that at least one of A.sup.1 to A.sup.4 is the carbon atom, and X.sup.1 and R.sup.1 bond to the carbon atom. n represents an integer of 0 to 3. When n is 2 or more, a plurality of R.sup.1 may be identical to or different from each other, and a plurality of R.sup.1 may bond to each other to form a ring structure.]

A golf ball core, mantle, and/or cover layer(s) of golf ball having a composition comprising functionalized aluminosilicate particles having a particle size of less than 50 m is disclosed herein. The aluminosilicate microspheres with an average diameter less than 50 m are functionalized with, but not limited to, polysulfide, vinyl, amino, epoxy, hydroxyl, carboxyl, methacryloyl, hydrocarbon, mercapto and isocyanate.

The present invention is a modified resin for a molded article obtained by modifying an ethylene/unsaturated carboxylic acid copolymer with guanidine carbonate, wherein a melt flow rate of the ethylene/unsaturated carboxylic acid copolymer is 20 (g/10 minutes) or more and 600 (g/10 minutes) or less.

In order to satisfy at a high level the golf ball flight and control performances relied on by professional golfers and skilled amateurs, this invention provides a multi-piece solid golf ball G having a core 1, a cover 3 and an intermediate layer 2 therebetween wherein the core is formed of a rubber composition that includes an alcohol having a value obtained by dividing the molecular weight of the alcohol by the number of hydroxyl groups thereon which is 70 or less. Also, letting Hc be the JIS-C hardness at the center of the core, H12 be the JIS-C hardness at a position 12 nun from the core center and Ho be the JIS-C hardness at the surface of the core, the core has a hardness profile in which these hardnesses satisfy fixed relationships defined by specific formulas.

A golf ball comprising a core comprising an inner core center and an outer core layer disposed over the inner core center. The inner core center has a deflection of greater than 0.210 inch under a load of 100 kilograms, and the entire the core has a deflection ranging from 0.130 inch to 0.105 inch under a load of 100 kilograms. A mantle layer is disposed over the core and a cover is disposed over the mantle.

The present invention generally relates to golf balls having an internal skeletal structure that can be self-supporting. The golf ball preferably contains a spherical hollow inner core that is gas or liquid-filled. The ball further comprises an outer shell skeletal structure having a spherical shape and containing apertures that form hollow compartments. In one version, the skeletal structure supports itself and the space inside and around the skeletal structure is hollow. In another embodiment, the space is solid, for example, it may be foam-filled. In yet another version, the hollow space is filled with liquid. Multi-piece golf balls having outer cores, inner covers, and intermediate layers can be made.

In order to satisfy at a high level the golf ball flight and control performances relied on by professional golfers and skilled amateurs, this invention provides a multi-piece solid golf ball G having a core 1, a cover 3 and an intermediate layer 2 therebetween wherein the core is formed of a rubber composition that includes a lower alcohol having a molecular weight below 200. Also, letting Hc be the JIS-C hardness at the center of the core, H12 be the JIS-C hardness at a position 12 mm from the core center and Ho be the JIS-C hardness at the surface of the core, the core has a hardness profile in which these hardnesses satisfy fixed relationships defined by specific formulas.

Golf balls and golf ball components made using three-dimensional (3D) additive manufacturing systems are provided. The golf ball includes at least one three-dimensional piece. Preferably, a continuous liquid interface printing method is used to make the three-dimensional structure. Ultraviolet (UV)-light polymerizable materials are used in the method. The method may be used to make single-piece or multi-piece balls. For example, the ball may include an inner core produced by the liquid interface printing method. An outer core layer may be disposed about the inner core, and a cover comprising inner and outer cover layers may encapsulate the core assembly to form the finished golf ball. The outer core and cover layers may be made using conventional molding technologies or the methods of this invention.

The invention provides a golf ball having a core and a cover of one or more layer encasing the core, wherein the core has a center core and a foamed outer layer that directly, or indirectly through another layer, envelops the center core. The foamed outer layer is made of a rubber composition that includes a base rubber, a co-crosslinking agent and an organic peroxide. The foamed outer layer has an inside portion facing the ball center and an outside portion facing the outside of the ball that are unfoamed regions, and contains a foamed region in an intermediate portion therebetween. A method of manufacturing such a golf ball is also provided.