Abstract: In a golf ball having a core, envelope layer, intermediate layer and cover, the core has a specific hardness profile, the resin materials making up either or both of the envelope layer and the intermediate layer has a material hardness on the Shore D hardness scale of at least 65 and has a specific gravity of at least 1.05, and the Shore C hardness relationships among the core center, surface of the envelope-encased layer and surface of the intermediate layer-encased sphere satisfy the following conditions: surface hardness of envelope layer-encased sphere<surface hardness of intermediate layer-encased sphere,??(1) surface hardness of intermediate layer-encased sphere?center hardness of core?40.??(2) This ball achieves a good distance on shots with utility and iron clubs, is receptive to spin in the short game, and has a soft feel at impact on all shots, making it useful to amateur golfers.

Abstract: Golf balls of the invention include at least one core layer comprised or consisting of a homogenous rubber-based core composition with a plurality of functionalized inorganic aluminosilicate ceramic microspheres dispersed throughout without agglomerating to create a relatively higher cross-link density of the core layer material. In golf balls of the invention, cross-link density gradients may be created between core layers by pre-electing the presence/absence, amount, type, and degree of functionalization of the plurality of functionalized inorganic aluminosilicate ceramic microspheres in two given core layers to target important properties such as resilience/CoR and desired playing characteristics such as distance.

Abstract: An object of the present invention is to provide a cured product of a golf ball rubber composition imparting excellent durability. The present invention provides a cured product of a golf ball rubber composition cured from a golf ball rubber composition containing (a) a base rubber, (b) an ?,?-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, wherein the cured product of the golf ball rubber composition satisfies the following mathematical formula (1): Y<(0.1×X)?1.30??(1) in the formula (1), Y represents an effective crosslinking density of the cured product of the rubber composition (mmol/cc), and X represents an amount of the component (b) with respect to 100 parts by mass of (a) the base rubber (parts by mass).

Abstract: Golf ball comprising at least one layer that is comprised of an air-cured elastomer composition comprising an elastomer and an organic peroxide curing agent.

Abstract: Golf balls of the invention include at least one core layer comprised or consisting of a homogenous rubber-based core composition with a plurality of functionalized inorganic aluminosilicate ceramic microspheres dispersed throughout without agglomerating to create a relatively higher cross-link density of the core layer material. In golf balls of the invention, cross-link density gradients may be created between core layers by pre-electing the presence/absence, amount, type, and degree of functionalization of the plurality of functionalized inorganic aluminosilicate ceramic microspheres in two given core layers to target important properties such as resilience/CoR and desired playing characteristics such as distance.

Abstract: A golf ball a core, one or more intermediate layers, and one or more cover layers. The core may comprise an inner portion and an outer portion. One or more layers of the golf ball may be formed by the application of ultrasonic welding on two half shells to form. One or more of the layers may be formed by a number of different chemical compositions, and may have varying thicknesses, hardnesses, coefficients of restitution, and PGA compression. The golf ball itself may have varying coefficient of restitution and PGA compression, depending on the layers.

Abstract: A resin composition for golf balls includes (a) an acid-containing copolymer having an amount of acid constituent per 100 wt % of the sum of monomer units in the copolymer that is from 1 to 30 wt %, and (b) an amine-containing polymer having a branched structure. The resin composition imparts golf balls with an excellent rebound resilience and also confers an outstanding durability to repeated impact and an outstanding scuff resistance, making it particularly useful as a cover material in golf balls.

Abstract: Dual core golf ball constructions achieving consistent and repeatable concentricity by incorporating/using an assembly of dual core components comprising a solid spherical inner core component and three outer core components that are collectively compression molded about the solid spherical inner core component to create an outer core layer thereabout. The three outer core components include a first half-shell, a second half-shell; and a ring-shaped securing plate such that the solid spherical inner core component is immovably centered within the outer core layer. Each of the first half-shell, the ring-shaped securing plate, and the second half-shell is comprised of the same rubber composition(s) and possess strong cohesive and adhesive bonds at parting lines between the three molded assembly parts and collectively create an outer core layer having one or more uniform property profile, such as a hardness gradient throughout, without interruption at parting lines between the three outer core components.

Abstract: A golf ball with improved durability is disclosed herein. The golf ball has a core comprising a polybutadiene material and methyl methacrylate, butadiene, styrene (MBS) with a weight percentage of MBS ranging from 0.5 to 5 weight percent of the core.

Abstract: Golf balls having covers made of thermoplastic polyurethane compositions are provided. Multi-piece golf balls can be made. In one embodiment, the outer cover layer is formed from a composition comprising a thermoplastic polyurethane and multi-functional hydroxyl compound. Mixtures of multi-functional amines and imines, and multi-functional isocyanates, and solvent, can be applied to the outer cover to form at least a partially cross-linked cover. The cover composition can further include catalysts, ultraviolet (UV)-light stabilizers, and other additives. The coating methods have many benefits and the finished balls have good physical properties.

Abstract: In a multi-piece solid golf ball having a core formed of a rubber composition, an intermediate layer formed of a polyurethane material and a cover, the ball satisfies the following condition: surface hardness of ball?surface hardness of intermediate layer-encased sphere. When the ball is struck with a driver at a head speed of 40 m/s, the sum of the time t1 required from contact initiation between the driver and ball for deformation of the ball to reach a maximum value and the time t2 required from the state of maximum ball deformation for the ball and driver clubface to separate is at least 685 microseconds, and the ratio t2/t1 is at least 1.35, and the core has a specific hardness profile. This ball has an excellent flight performance when hit by low or moderate head-speed golfers, is receptive to spin on approach shots and has a good, soft feel at impact.

Abstract: 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.

Abstract: 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.

Abstract: In a multi-piece solid golf ball having a core, an envelope layer, an intermediate layer and a cover, the core, an intermediate layer-encased sphere and the ball have surface hardnesses which satisfy a specific relationship, and the envelope layer, the intermediate layer and the cover have thicknesses which satisfy a specific relationship. Also, the core has a hardness profile in which the hardnesses at the core surface, core center, a position 5 mm from the core center, and a position midway between the surface and center of the core satisfy specific relationships. This golf ball, when used by mid- and high-level amateurs, enables the golfer to maintain an adequate distance on shots with a driver and achieve a good distance on iron shots, has a good spin performance on approach shots and has a good feel on impact. In addition, the ball has an excellent scuff resistance when struck with a grooved wedge.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Multi-layered golf balls having at least one layer made of a foamed silicone composition are provided. Multi-layered golf balls having at least one layer made of non-foamed silicone elastomer composition also are provided. For example, three-piece, four-piece, and five-piece golf balls containing different core and cover structures can be made. The foamed silicones have good thermal stability and durability without sacrificing resiliency. The non-foamed silicone elastomers have high elongation, tensile strength, chemical/fluid-resistance, and weatherability properties. These compositions can be used to form any layer, for example, core, intermediate, or cover, in the golf ball.

Abstract: 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.

Abstract: In a multi-piece solid golf ball having a core, an envelope layer, an intermediate layer and a cover, the core is formed primarily of a base rubber and has a diameter set in a specific range, the envelope layer, intermediate layer and cover are each formed of resin materials, and the envelope layer is formed into two layers—an inner layer and an outer layer. The center and surface hardnesses of the core, the surface hardness of the inner envelope layer-encased sphere, the surface hardness of the outer envelope layer-encased sphere, the surface hardness of the intermediate layer-encased sphere and the surface hardness of the ball together satisfy a specific relationship. This ball achieves a satisfactory distance on full shots both with a driver and with irons, in addition to which it is superior in the short game and has a good feel at impact and an excellent scuff resistance.

Abstract: 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.

Abstract: Golf balls having covers made of thermoplastic polyurethane compositions are provided. Multi-piece golf balls can be made. In one embodiment, the outer cover layer is formed from a composition comprising a thermoplastic polyurethane and multi-functional hydroxyl compound. Mixtures of multi-functional amines and imines, and multi-functional isocyanates, and solvent, can be applied to the outer cover to form at least a partially cross-linked cover. The cover composition can further include catalysts, ultraviolet (UV)-light stabilizers, and other additives. The coating methods have many benefits and the finished balls have good physical properties.

Abstract: In a multi-piece solid golf ball having a core, a cover and an intermediate layer therebetween, the core, an intermediate layer-encased sphere and the ball have surface hardnesses which satisfy a specific relationship, and the intermediate layer and the cover have thicknesses which satisfy a specific relationship. Also, the core has a hardness profile in which the hardnesses at the core surface, core center, a position 5 mm from the core center, and a position midway between the surface and center of the core satisfy specific relationships. This golf ball, when used by mid- and high-level amateurs, enables the golfer to maintain an adequate distance on shots with a driver and achieve a good distance on iron shots, has a good spin performance on approach shots and has a good feel on impact. In addition, the ball has an excellent scuff resistance when struck with a grooved wedge.

Abstract: Golf balls comprising a multi-layer core and a cover are disclosed. The multi-layer core comprises a center, an intermediate core layer, and an outer core layer. At least one layer of the multi-layer core is a high specific gravity layer.

Abstract: 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.

Abstract: A golf ball with improved durability is disclosed herein. The golf ball has a core comprising a polybutadiene material and methyl methacrylate, butadiene, styrene (MBS) with a weight percentage of MBS ranging from 0.5 to 5 weight percent of the core.

Abstract: A golf ball with a center core comprising 1,4 polybutadiene with a cis content more than 50% and containing a metal salt of acrylate, wherein the 1,4 polybutadiene has 5 to 60 weight percent of a metal salt of acrylate, is disclosed herein. The metal salt of acrylate is preferably selected from zinc, magnesium, sodium, and calcium.

Abstract: The present invention is directed to multi-layer golf balls including a layer formed from a relatively soft or low modulus HNP composition and a layer formed from a relatively hard or high modulus HNP composition. Optionally, the soft (or low modulus) HNP composition and/or the hard (or high modulus) HNP composition is plasticized or is replaced with a different plasticized acid copolymer composition.

Abstract: Multi-layered golf balls having at least one layer made from silicone (polysiloxane) elastomers; silicone (polysiloxane) elastomer/polyurethane blends; polycarbonate-polysiloxane blends and copolymers; and polycarbonate-polysiloxane/polyurethane blends are provided. For example, three-piece, four-piece, and five-piece golf balls containing different core and cover structures can be made. The polysiloxane compositions have good thermal stability and durability without sacrificing resiliency. The polysiloxane compositions also have high elongation, tensile strength, chemical/fluid-resistance, and weatherability properties. These compositions can be used to form any layer, for example, core, intermediate, or cover, in the golf ball.

Abstract: In a golf ball having a two-layer core consisting of an inner core layer and an outer core layer, one or more intermediate layer, and a cover serving as an outermost layer, the inner core layer and outer core layer are each formed primarily of a base rubber, the inner core layer has a diameter of at least 21 mm, the intermediate layer and the cover are each formed primarily of a resin material, and the overall core has a specific hardness profile. The golf ball has a high initial velocity while holding down the spin rate on full shots with a driver or long iron, thus enabling a good distance to be achieved. The ball also has a high controllability in the short game.

Abstract: Multi-layered golf balls having a core made of a foamed composition, preferably polyurethane foam, are provided. The ball includes a dual-layered core having a foam inner core (center) and surrounding outer core layer. The outer core layer may be made from a non-foamed thermoset material such as polybutadiene rubber. The ball further includes an inner cover, preferably made from an ionomer composition comprising an O/X-type acid copolymer, wherein O is ?-olefin, and X is a C3-C8 ?,?-ethylenically unsaturated carboxylic acid. The outer cover may be made from a non-foamed thermoset or thermoplastic material such as polyurethane. Preferably, the specific gravity of the inner cover is greater than the specific gravity of the outer core, which is greater than the specific gravity of the inner core. The finished ball has good distance and low-spin properties.

Abstract: Multi-piece golf balls containing a multi-layered core structure are provided. The core structure includes a small, heavy inner core (center) having a relatively high specific gravity, an intermediate core layer, and a surrounding outer core layer. The layers of the core structure may have different hardness gradients. The center of the core comprises a metal material such as copper, steel, brass, tungsten, titanium, aluminum, and alloys thereof dispersed in a thermoset polymeric matrix. The intermediate core layer is preferably formed from a first thermoplastic composition such as an ethylene acid copolymer ionomer resin; and the outer core layer is preferably formed from a second thermoplastic composition. The resulting ball has high resiliency and good spin control.

Abstract: Multi-piece golf balls containing a dual-layered core and dual-layered cover are provided. The core structure includes a small, heavy inner core (center) having a relatively high specific gravity, and a surrounding outer core layer. The core layers may have different hardness gradients. The center of the core comprises a metal material such as copper, steel, brass, tungsten, titanium, aluminum, and combinations and alloys thereof preferably dispersed in a thermoplastic polymeric matrix. The outer core layer is preferably formed from a thermoset composition such as polybutadiene. The multi-layered cores and covers have selective specific gravity relationships between the different layers. This helps provide the ball with good flight distance and spin control. The resulting balls have good resiliency and other playing performance properties.

Abstract: The present invention provides a novel golf ball construction including a layer having a design based on a minimal surface. The layer is defined by an envelope shape having an outer boundary and an inner boundary, and consists of a minimal surface and an interstitial space, the minimal surface and interstitial space being bounded by the envelope shape. The minimal surface is a single continuous surface which does not intersect itself and has zero mean curvature.

Abstract: Golf ball comprising layer(s) consisting of a mixture consisting of: i) ethylene acid copolymer(s) and/or ionomer(s); ii) polyethylene(s); iii) polymeric epoxy crosslinker(s); and iv) compatibilizing polymer(s). The ethylene acid copolymer(s)/ionomer(s) and the polyethylene(s) may be included in a blend in a wt % ratio of from about 85:15 to 55:45; the at least one polymeric epoxy crosslinker and compatibilizing polymer may be included in amounts, based on 100 parts of the blend, of from about 2.0 to about 10.0 parts; and from about 1.0 to about 10.0 parts, respectively. The polyethylene may be polyethylene butene; polyethylene hexene; polyethylene octene; and combinations thereof. Each ethylene acid copolymer, polyethylene, polymeric epoxy crosslinker, and compatibilizing polymer has a density less than 1.0 g/cm3. The mixture is moldable and meanwhile possesses similar desirable CoR, DCM compression, Shore D hardness, and Shore C hardness as a mixture consisting of ingredients i), ii) and iv).

Abstract: Multi-piece golf balls containing a multi-layered core structure are provided. The core structure includes a small, heavy inner core (center) having a relatively high specific gravity, an intermediate core layer, and a surrounding outer core layer. The layers of the core structure may have different hardness gradients. In one preferred embodiment, each core layer has a positive hardness gradient. The center of the core comprises a metal material such as copper, steel, brass, tungsten, titanium, aluminum, and alloys thereof. The intermediate core layer is preferably formed from a first thermoset composition such as polybutadiene rubber, and the outer core layer is preferably formed from a second thermoset composition. The resulting ball has high resiliency and good spin control.

Abstract: 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.

Abstract: In a multi-piece solid golf ball having a core, a cover and an intermediate layer therebetween, the core, an intermediate layer-encased sphere and the ball have surface hardnesses which satisfy a specific relationship, and the intermediate layer and the cover have thicknesses which satisfy a specific relationship. Also, the core has a hardness profile in which the hardnesses at the core surface, core center, a position 5 mm from the core center, and a position midway between the surface and center of the core satisfy specific relationships. This golf ball, when used by mid- and high-level amateurs, enables the golfer to maintain an adequate distance on shots with a driver and achieve a good distance on iron shots, has a good spin performance on approach shots and has a good feel on impact. In addition, the ball has an excellent scuff resistance when struck with a grooved wedge.

Abstract: In a golf ball having a two-layer core consisting of an inner core layer and an outer core layer, an intermediate layer and a cover, the core is formed primarily of a base rubber, the diameter of the inner core layer is at least 21 mm, the intermediate layer and cover are each formed primarily of a resin material, the overall core has a specific hardness profile, the inner core layer has a higher specific gravity than the outer core layer, and the sphere consisting of the core encased by the intermediate layer has a higher surface hardness than the ball. This golf ball has a high initial velocity at impact while holding down the spin rate on full shots with a driver or long iron, enabling a good distance to be achieved. The ball also has a good controllability in the short game.

Abstract: In a golf ball having a core, an intermediate layer and a cover, the intermediate layer-encased sphere has a higher surface hardness than the ball. The core hardness profile in the ball is designed such that the core surface has a Shore C hardness value which is at least 28 higher than the Shore C hardness value at the core center, and the surface areas A to F calculated from hardness differences between positions located at specific distances in the core and differences between the specific distances satisfy a specific formula. This golf ball has an excellent flight performance when struck by skilled amateur golfers and professionals, and also has a good controllability on shots with an iron.

Abstract: Golf balls comprising a multi-layer core and a cover are disclosed. The multi-layer core comprises a center, an intermediate core layer, and an outer core layer. At least one layer of the multi-layer core is a high specific gravity layer.

Abstract: Multi-layered golf balls containing a dual-core structure are provided. The core structure includes an inner core (center) comprising a foam composition, preferably foamed polyurethane. The outer core layer is preferably formed from a non-foamed thermoset composition such as polybutadiene rubber. The core layers have different hardness and specific gravity levels. The specific gravity (density) of the foam inner core is preferably less than the density of the outer core layer. The core assembly preferably has a positive hardness gradient extending across the entire assembly. The core structure and resulting ball have relatively good resiliency.

Abstract: Multi-piece golf balls having a solid core and cover are provided. The ball contains a small, heavy inner core and surrounding outer core layer. The inner core preferably contains metal powder such as copper, steel, brass, tungsten, titanium, nickel, iron, tin, and bronze particles dispersed in a thermoset or thermoplastic polymeric matrix. For example, a polybutadiene rubber matrix may be used. In one preferred embodiment, the inner core contains elemental iron powder. Preferably, the particles have a weight average size in the range of about 10 ?m to about 450 ?m. In one embodiment, the outer surface of the inner core has a structure with projecting members. For example, the outer surface may contain multiple projecting ribs with gaps located between the ribs. The ball includes a cover surrounding the core structure. The cover may be multi-layered.

Abstract: A polyurethane-ionomer hybrid resin composition for a golf ball cover having excellent elastic reaction force and backspin performance comprises 100 parts by weight of a modified ionomer having a number average molecular weight in a range of 1,000 to 2,400, provided as a reaction product generated by a reaction among a polyol including hydroxyl groups on opposing ends of the polyol, a monomer of acrylic acid or methacrylic acid having 2 to 3 functional groups, and zirconia, and modified in such a manner that a polyester oligomer in a zirconia complex state and a zirconia filled state is added to an ionomer resin to be reacted, and a portion of unsaturated carboxylic acid of an ionomer is neutralized to be zirconium and additionally polymerized to be the polyester oligomer; 20 to 40 parts by weight of a block polyurethane prepolymer with respect to 100 parts by weight of the modified ionomer; 70 to 100 parts by weight of the ionomer with respect to 100 parts by weight of the modified ionomer; and 1 to 10 parts

Abstract: In a multi-piece solid golf ball made up of, successively, a core, an intermediate layer and a cover having numerous dimples on the surface thereof, the intermediate layer is formed of a resin material and the cover is formed of a urethane resin material, each having a specific respective Shore D hardness. The ball has a specific (intermediate layer thickness)/(core diameter) value and a specific (cover thickness)/(core diameter) value, and the core has a specific deflection. The sphere consisting of the core encased by the intermediate layer has an initial velocity A and the core has an initial velocity B which together satisfy the condition A?B?0 m/s. This golf ball provides an increased distance and has both a soft feel when played and a high durability to repeated impact.

Abstract: 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.

Abstract: 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.

Abstract: Golf ball comprising first layer of first polymeric composition, and second layer adjacent to first layer and comprising second polymeric composition different than first polymeric composition and comprising throughout: (i) passivated TiO2 particulates amount of from about 1 wt. %-10 wt. % based on total weight of second polymeric composition; and (ii) silane-containing adhesion promoter(s), for example, organosilanes and/or organosiloxanes, such that a given amount thereof within the range of from about 0.1 wt. % to about 5.0 wt. % has a first required amount of free functional groups to bond the second layer and the first layer at an interface in addition to a second required amount of functional groups bonding and/or crosslinking ingredients within the second polymeric composition of the second layer. Neither layer is surface treated with at least one silane-containing adhesion promoter, nor is a tie layer disposed there between.

Abstract: A golf ball comprising an inner core comprising polybutadiene, and an outer core comprising a polybutadiene material, a graphene material and a carbon nanotube material (CNT) is disclosed herein. Improved durability of the core by using a mixture of graphene and CNT can result in higher mean time to fail (MTTF) upon repeated impact in a high speed testing device, or with a golf club in normal play.

Abstract: An object of the present invention is to provide a golf ball having good spin performance on approach shots and good shot feeling as well as excellent stain resistance by precisely controlling physical properties of a paint film actually formed on a surface of a golf ball body. The present invention provides a golf ball comprising a golf ball body and a paint film formed on a surface of the golf ball body, wherein the paint film is such that a linear approximation curve obtained by a least square method has a slope in an absolute value ranging from 0.0001 to 0.0020 when a loss tangent tan ? thereof measured by a nanoindentation method is plotted as a vertical axis against a measuring frequency (Hz) as a horizontal axis, and that an elastic modulus thereof measured by a nanoindentation method ranges from 0.040 GPa to 0.600 GPa.