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 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.

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.

An object of the present disclosure is to provide a golf ball having excellent durability and flight distance and good shot feeling for an average golfer who hits a golf ball at a slow head speed. The present disclosure provides a golf ball comprising a spherical core and at least two cover layers covering the spherical core, wherein a difference between a core surface crosslinking density and a core center crosslinking density is more than 1.0×10.sup.2 mol/m.sup.3 and less than 9.0×10.sup.2 mol/m.sup.3, a hardness difference between a core surface hardness Cs (Shore C hardness) and a core center hardness Co (Shore C hardness) is 13.0 or more and 30.0 or less, a compression deformation amount of the core when applying a load from an initial load of 98 N to a final load of 1275 N to the core is less than 3.8 mm, and the at least two cover layers include a first cover layer and a second cover layer positioned closer to the spherical core than the first cover layer, an average hardness Dave=(Ti×Hi+To×Ho)/(Ti+To) of the first cover layer and the second cover layer is 55 or more, wherein To (mm) is a thickness of the first cover layer, Ho (Shore D) is a slab hardness of the first cover layer, Ti (mm) is a thickness of the second cover layer, and Hi (Shore D) is a slab hardness of the second cover layer.

A golf ball resin composition includes (a) an olefin-α,β-unsaturated carboxylic acid copolymer and/or a metal ion neutralization product thereof or an olefin-α,β-unsaturated carboxylic acid-α,β-unsaturated carboxylic acid ester copolymer and/or a metal ion neutralization product thereof, (b) a phenolic resin and (c) a compound having at least two oxazoline groups per molecule, wherein the content of component (C) is from 0.1 to 5 parts by weight per 100 parts by weight of components (a) and (b) combined. The resin composition has excellent tensile properties and, when used in a golf ball, provides the ball with an excellent durability without lowering the spin performance and distance performance of the ball. The resin is especially useful as a golf ball cover material for an outermost layer or an intermediate layer.

In a golf ball having a core, an intermediate layer and a cover, the core is formed primarily of a base rubber, has a diameter set in a specific range and has a specially designed internal hardness profile, the intermediate layer and the cover are each formed of resin materials, and the surface hardness of the ball is higher than the surface hardness of the intermediate layer-encased sphere. This ball achieves a satisfactory distance on full shots with a driver and with long and middle irons, provides a good spin performance on approach shots, and has a durability to repeated impact and a scuff resistance that are both excellent.

A golf ball comprising: (a) a core; (b) an inner mantle layer; (c) an intermediate mantle layer; (d) an outer mantle layer; and (e) at least one cover layer; wherein the core has a PGA compression of less than 70, and the core/inner mantle layer/intermediate mantle layer combined construct has a PGA compression of at least 30.

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.

In a multi-piece solid golf ball having a core, an envelope layer, an intermediate layer and a cover, the envelope layer is formed into two layers—an inner envelope layer and an outer envelope layer. The inner envelope layer-encased sphere, outer envelope layer-encased sphere, intermediate layer-encased sphere and ball have respective surface hardness that satisfy a specific relationship. The inner envelope layer or outer envelope layer is formed primarily of one or more elastomer, and further the core has a particular hardness profile. This ball has an excellent flight when struck by golfers whose head speeds are not that fast and has a good, soft feel at impact, thus making it highly suitable for amateur golfers,

In a golf ball having a core, an intermediate layer and a cover, the core is formed primarily of a base rubber and has a diameter set in a specific range, and the intermediate layer and cover are each formed of resin materials. The core has an internal hardness such that, regarding the hardness at the core center, the hardnesses at positions located at 2 mm intervals from the core center outward up to 16 mm and the core surface hardness, the hardness differences therebetween are set within a specific range. The ball surface hardness is set so as to be higher than the surface hardness of the intermediate layer-encased sphere. This ball achieves a satisfactory distance on full shots not only with a driver, but also with a long iron or a middle iron, in addition to which it has an excellent durability to repeated impact.

In a golf ball having a core, an intermediate layer and a cover, the core is formed primarily of a base rubber, has a diameter set in a specific range and has a specially designed internal hardness profile, the intermediate layer and the cover are each formed of resin materials, and the surface hardness of the ball is higher than the surface hardness of the intermediate layer-encased sphere. This ball achieves a satisfactory distance on full shots with a driver and with long and middle irons, provides a good spin performance on approach shots, and has a durability to repeated impact and a scuff resistance that are both excellent.