Abstract: A multi-piece solid golf ball has a core, at least one intermediate layer and an outer layer. The core is formed of a single layer or of two or more layers. The interior hardness profile of the core is set in a specific range, and the relationship between the compressive deformations of the core and the golf ball under given loadings is set in a specific range. The outer layer is formed primarily of a thermoplastic polyurethane material, and has a material hardness that is set in a specific range.

Abstract: A golf ball is disclosed which includes a central core; one or more mantle layers and an outer cover layer and where one or more of the core and one or more mantle layers is coated with a coating composition which includes one or more of the following components; a polysulfide silane; a waterborne polyurethane resin composition; a waterborne urethane modified acrylic resin composition; or an epoxy resin composition.

Abstract: Multi-piece golf balls having at least one component made of a rubber composition comprising substantially oriented nanostructures are provided. For example, the nanostructures may be in the form of nanofibers, nanorods, nanotubes, and nanoparticles. The multi-piece golf ball contains a core, which may have a dual-core construction including a center and surrounding outer core layer or other multi-layered structure. Preferably at least one of the core layers is formed from a polybutadiene rubber composition comprising the nanostructures. The polybutadiene rubber may be chemically or non-chemically modified. The polybutadiene preferably has a cis-bond content of at least 80%.

Abstract: A golf ball comprising a core, a cover and at least on intermediate layer therebetween. The intermediate layer includes pigment which contributes to the color or appearance of the ball and the cover is at least partially transparent such that the intermediate layer is at least partially visible. The cover is also comprised of an optical enhancer.

Abstract: Multi-piece, solid golf balls containing an inner core, an intermediate layer surrounding the core, and an outer cover are provided. At least one layer is made from an epoxy composition comprising a curing agent such as zinc diacrylate or zinc dimethacrylate. The epoxy composition is produced by reacting an epoxy prepolymer with a curing agent. Preferably, the epoxy composition is used to form an intermediate and/or cover layer resulting in a golf ball having high resiliency, good impact durability, and soft feel.

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 materials such as copper, steel, brass, tungsten, titanium, nickel, iron, tin, and bronze particles. The outer surface of the inner core preferably has a non-uniform structure and includes 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: The present invention is directed to golf balls consisting of a dual-layer core and a cover. The core consists of a center having a center hardness of 50 Shore C or greater and formed from a low modulus HNP composition, and an outer core layer having a surface hardness of 75 Shore C or greater and formed from a high modulus HNP composition. Low modulus HNP compositions of the present invention have a modulus of from 1,000 psi to 50,000 psi. High modulus HNP compositions of the present invention have a modulus of from 25,000 psi to 150,000 psi. The modulus of the highly neutralized copolymer of the low modulus HNP is at least 10% less than the modulus of the highly neutralized copolymer of the high modulus HNP composition. The cover consists of an inner cover layer formed from a thermoplastic composition and an outer cover layer formed from a polyurethane or polyurea composition.

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

Abstract: Multi-piece golf balls containing a multi-layered core structure having layers with different hardness gradients and specific gravities are provided. The core structure includes a small, heavy inner core (center) having a relatively high specific gravity with metal material preferably dispersed in a thermoset composition. 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: A first golf ball 2 includes a core 4, a mid-layer 6, and a cover 8. The core 4 includes a center 10 and an envelope layer 12. The mid-layer 6 includes a metal ion source (C) that can neutralize an ionomer resin. The mid-layer 6 has a melt flow rate (at 190° C. and 2.16 kg) of 4 g/10 minute or greater. The difference (H3?H1) between the JIS-C hardness H3 of the cover 8 and the JIS-C central hardness H1 of the center 10 is equal to or greater than 45. A second golf ball 22 includes a core 24, a mid-layer 28, and a cover 30. The mid-layer 28 has a melt flow rate (at 190° C. and 2.16 kg) of 4 g/10 minute or greater. Preferably, the mid-layer 28 includes a high melt viscosity resin (A), a low melt viscosity ionomer resin (B), and a metal ion source (C1).

Abstract: A golf ball with a controlled moment of inertia and controlled spin rate is disclosed. In one embodiment, the golf ball comprises a core, an intermediate layer and a cover, wherein the intermediate layer comprises a foamed highly neutralized polymer, has its specific gravity reduced to less than about 1.05, wherein the reduction in the specific gravity of the intermediate layer is less than about 25% to minimize the reduction in the coefficient of restitution of the golf ball to about 6% or less.

Abstract: The present invention is directed to an improved golf ball displaying the desired spin profile and having a generally rigid, thermoset polybutadiene outer core surrounding a relatively soft, low compression inner core. In general, this golf ball has an inner core and at least one outer core layer surrounding the inner core. The inner core has a hardness less than a hardness of the outer core and a specific gravity less than or equal to the outer core specific gravity. Overall the inner core compression and outer core are formulated to provide a combined overall core compression of greater than about 50, preferably greater than about 70. A cover layer is provided to surround and to cover the outer core layer.

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. The intermediate core layer is preferably formed from a thermoset composition such as polybutadiene rubber, and the outer core layer is preferably formed from a thermoplastic composition such as an ethylene acid copolymer. The resulting ball has high resiliency and good spin control.

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. 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: Multi-piece golf balls containing a dual-core structure are provided. The core structure includes a small, heavy inner core (center) having a relatively high specific gravity and a surrounding outer core layer having a relatively low specific gravity. 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. The outer core layer is formed from a thermoset composition, such as polybutadiene rubber, or from a thermoplastic composition, such as an ethylene acid copolymer ionomer resin.

Abstract: Multi-layer golf balls comprising a center, intermediate layer, and cover are disclosed. The center is formed from a highly-neutralized acid copolymer composition.

Abstract: Golf balls comprising a multi-layer core and a cover are disclosed. The multi-layer core comprises a layer formed from a highly neutralized polymer composition and a layer formed from a thermoset rubber.

Abstract: Multilayer golf balls comprising a thermoplastic or thermoset cover disposed about four or more thermoplastic layers are disclosed.

Abstract: A golf ball includes a ‘dual core’ formed from an inner core layer and an outer core layer. The inner core has an outer surface and a center and is typically formed from a substantially-homogenous rubber composition such that the center of the core has a hardness of about 72 Shore C to about 78 Shore C and a trans content of about 5% to 9%, and the outer surface of the inner core has a trans content of about 5% to 9%. The trans content of the outer surface and the center of the inner core are preferably within 2% of each other and, more preferably are substantially the same to define a zero trans gradient along a radius of the inner core.

Abstract: The present invention relates to golf balls comprising a crosslinked ionomer composition formed by the reaction of either one or more ionomers, or an ionomer precursor composition, with one or more crosslinking agents including polyisocyanates, blocked polyisocyanates, polyurethane prepolymers, blocked polyurethane prepolymers, polyurea prepolymers, blocked polyurea prepolymers, polyamines, blocked polyamines and dicyanodiamides. The resulting modified ionomer compositions exhibit increased tensile strength and a decrease in tensile elongation as compared to the uncrosslinked ionomer analogs while maintaining Shore D hardness.

Abstract: A golf ball including a unitary core having a volume, an outer surface, a geometric center, and an outermost transition volume adjacent to the outer surface, the core being formed from a substantially homogenous composition; and a cover layer including ionomer, metallocene-catalyzed polymer, polyester, polyamide, non-ionomeric thermoplastic elastomer, copolyether-ester, copolyether-amide, polycarbonate, polybutadiene, polyisoprene, or polystyrene block copolymer. The outermost transition volume is disposed between the core outer surface and the geometric center, the transition volume has an outer portion congruent with the core outer surface, and comprises the outermost 45% of the core volume or less. Both a hardness of the core outer surface and a hardness within the outermost transition volume are less than the hardness of the geometric center to define a negative hardness gradient.

Abstract: The invention provides a multi-piece solid golf ball composed of a solid core, a cover, at least one intermediate layer situated therebetween, and a plurality of dimples on a surface of the ball. The diameter of the solid core, the deflection of the core when compressed under a final load of 130 kgf from an initial load of 10 kgf, the hardness at the center of the core, the hardness in a region 5 mm to 10 mm from the center of the core, the hardness 15 mm from the center of the core, and the surface hardness are set within specific ranges. The intermediate layer is composed primarily of a material obtained by mixing under applied heat a specific resin composition. The golf ball of the invention has an excellent flight performance, feel, controllability and scuff resistance.

Abstract: An object of the present invention is to provide a golf ball resin composition with an excellent resilience and fluidity. Another object of the present invention is to provide a golf ball resin composition with a high hardness and durability. Yet another object of the present invention is to provide a golf ball traveling a great distance with an ionomer cover. The present invention provides a golf ball resin composition comprising, (A) an ionomer resin consisting of a metal ion-neutralized product of a binary copolymer composed of an olefin and an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms; (B) a binary copolymer composed of an olefin and an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms, and (C) a zinc compound, wherein a content ratio ((A)/(B)) of (A) component to (B) component ranges from 50/50 to 80/20 in a mass ratio and a content of (C) component ranges from 0.

Abstract: The invention provides a multi-piece solid golf ball composed of a solid core, a cover, at least one intermediate layer situated therebetween, and a plurality of dimples on a surface of the ball. The diameter of the solid core, the deflection of the core when compressed under a final load of 130 kgf from an initial load of 10 kgf, the hardness at the center of the core, the hardness in a region 5 mm to 10 mm from the center of the core, the hardness 15 mm from the center of the core, and the surface hardness are set within specific ranges. The intermediate layer is composed primarily of a material obtained by mixing under applied heat a specific resin composition and the cover is formed primarily of polyurethane. And, the number of dimples and the trajectory volume TVT are set within specific ranges. The golf ball of the invention has an excellent flight performance, feel, controllability and scuff resistance.

Abstract: Golf ball 2 has spherical core 4 and cover 6 provided so as to cover this core 4. The core 4 has spherical center 8 and mid layer 10 provided so as to cover this center 8. The resilience coefficient Ec of the center 8, the resilience coefficient Em of the core 4 and the resilience coefficient Eb of the golf ball 2 satisfy the following formulae (1) and (2): Ec>Eb?Em??(1); Eb?Em?Ec?Eb??(2). The difference (Eb?Em) between the resilience coefficient Eb and the resilience coefficient Em is equal to or greater than 0.004. The difference (Ec?Eb) between the resilience coefficient Ec and the resilience coefficient Eb is equal to or greater than 0.004.

Abstract: Golf equipment having improved cut and shear resistance that includes a polyurea composition, preferably saturated and/or water resistant, formed of a polyurea prepolymer and a curing agent, wherein the polyurea prepolymer includes an isocyanate and an amine-terminated compound, and wherein the curing agent includes a hydroxy-terminated curing agent, amine-terminated curing agent, or a mixture thereof.

Abstract: Certain disclosed embodiments of the present invention concern a golf ball, which includes a core comprising a center, an outer cover layer; and optionally one or more intermediate layers, and where at least one or more of the core, outer cover layer, or one or more intermediate layers if present, includes a styrene ionomer, such as a styrene anhydride copolymer, a basic salt of a styrene-?,?-unsaturated acid copolymer, or a styrene maleic anhydride copolymer. These styrene-based copolymers can be used in combination with additional polymer components.

Abstract: Multi-piece golf balls containing a dual-core structure are provided. The core structure includes a small, heavy inner core (center) having a relatively high specific gravity and a surrounding outer core layer having a relatively low specific gravity. 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. The outer core layer preferably is formed from a thermoset composition such as polybutadiene rubber. The resulting ball has high resiliency and good spin control.

Abstract: Multi-piece golf balls containing a dual-core structure are provided. The core structure includes a small, heavy inner core (center) comprising a metal material, for example, copper, steel, brass, tungsten, titanium, aluminum, and alloys thereof, and having a relatively high specific gravity. A surrounding outer core layer is disposed about the inner core and has a relatively low specific gravity. The outer core layer preferably is formed from a thermoplastic composition preferably an ethylene acid copolymer ionomer resin. The core structure may have different hardness gradients. The resulting ball has high resiliency and good spin control.

Abstract: The invention provides a golf ball material which is a resin mixture composed of (a) an olefin-methacrylic acid copolymer and/or an olefin-methacrylic acid-unsaturated carboxylic acid ester copolymer having a weight-average molecular weight (Mw) of from 120,000 to 200,000 and a weight-average molecular weight (Mw) to number-average molecular weight (Mn) ratio of from 4.0 to 7.0, or a metal neutralization product thereof, (b) an olefin-acrylic acid copolymer and/or an olefin-acrylic acid-unsaturated carboxylic acid ester copolymer having a weight-average molecular weight (Mw) of from 150,000 to 220,000 and a weight-average molecular weight (Mw) to number-average molecular weight (Mn) ratio of from 5.5 to 8.5, or a metal neutralization product thereof, (c) an organic acid or a metal salt thereof, and (d) a basic inorganic metal compound for neutralizing at least 70 mol % of acid groups in components (a) to (c), which resin mixture has a Shore D hardness of from 30 to 60.

Abstract: The invention provides a golf ball material which is a resin mixture composed of (a) an olefin-unsaturated carboxylic acid copolymer and/or an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer having a weight-average molecular weight (Mw) of from 120,000 to 200,000 and a weight-average molecular weight (Mw) to number-average molecular weight (Mn) ratio of from 4.3 to 6.6, or a metal neutralization product thereof, (b) an olefin-unsaturated carboxylic acid copolymer and/or an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer having a weight-average molecular weight (Mw) of from 120,000 to 200,000 and a weight-average molecular weight (Mw) to number-average molecular weight (Mn) ratio of from 6.8 to 9.

Abstract: A golf ball having at least a core and a composite layer comprising a fibrous material and a matrix material is provided. The matrix material preferably comprises a translucent polymer. Preferably, the fibrous material comprises fiber flock. Preferably, the fiber flock comprises fiber segments having a length less than one inch. The fiber segments may have substantially equal dimensions. In other instances, the fiber segments are of unequal dimensions. The golf balls preferably includes a translucent cover layer surrounding the composite layer and an intermediate layer disposed between the composite layer and the core.

Abstract: Golf balls comprising a multi-layer core and a cover are disclosed. The multi-layer core comprises at least one intermediate core layer formed from a metallic, composite, or inorganic/organic hybrid composition.

Abstract: An improved golf ball comprises a core with a coarse surface, a resin layer bonded to the coarse surface of the core, a reflective layer being a metal thin film with a glossy surface and coated on the resin layer by vacuum plating, and a transparent layer coated on the reflective layer. Through illumination of light, the reflective layer of the golf ball can reflect the light to glisten brighter after the golf ball is hit. The reflective layer also is less likely to be peeled off, atomized and damaged after the golf ball is hit, thus can increase the lifespan thereof.

Abstract: Multi-piece golf balls having a core made of a composition comprising a polybutadiene rubber blend are provided. The blend includes a non-metallocene catalyzed polybutadiene rubber and a metallocene-catalyzed polybutadiene rubber. Catalysts such as neodymium, nickel, and cobalt based catalysts may be used to make the non-metallocene catalyzed rubber. Catalysts such as ferrocene, cobaltocene, nickelocene, titanocene dichloride, zirconocene dichloride, and samraocene based catalysts may be used to make the metallocene-catalyzed rubber. The golf ball may contain single layered core or multi-layered cores. The core is surrounded by a cover having at least one layer. The resulting ball has high resiliency and a soft compression feel.

Abstract: Multi-layer golf balls comprising a center, intermediate layer, and cover are disclosed. The center is formed from a highly-neutralized acid copolymer composition.

Abstract: Golf ball with a novel combination of spin rate, lift coefficient, drag coefficients, and optionally moment of intertia: a golf ball with a low spin rate, a high lift coefficient, a low drag coefficient, and optionally a high moment of inertia; and a golf ball with a high spin rate, a low lift coefficient, a low drag coefficient, and optionally a low moment of inertia.

Abstract: A golf ball is formed including a core and a cover. The cover includes a thermoplastic inner cover layer and having a hardness between 55 and 60 Shore D, an outer cover layer having a hardness between 55 and 60 Shore D, and a non-ionomeric thermosetting polyurethane or polyurea intermediate cover layer disposed between the inner and outer cover layers. The intermediate cover layer has a hardness greater than the inner cover layer hardness and the outer cover layer hardness. The inner cover is formed from a partially- or fully-neutralized ionomer and the outer cover layer is formed from a polyurethane, a polyurea, or a urethane-urea blend.

Abstract: The present invention provides a golf ball comprising a golf ball body with a spherical core having one or more layers, an intermediate layer disposed outside the spherical core and a cover disposed outside the intermediate layer and a paint film formed on a surface of the golf ball body, and having a friction coefficient calculated using a contact force tester of 0.35 or more and 0.60 or less, wherein the golf ball body has specific plurality of dimples on the surface thereof, at least one layer of the spherical core is a rubber layer having a specific hardness distribution, and the rubber layer has a hardness at the outermost point which is greater than a hardness at the innermost point, and the intermediate layer has a slab hardness (Hm) which is greater than a slab hardness (Hc) of the cover.

Abstract: A golf ball 2 includes a core 4, an inner cover 6, and an outer cover 8. The core 4 includes a center 10, an inner envelope layer 12, and an outer envelope layer 14. The inner envelope layer 12 is formed by a rubber composition being crosslinked. The rubber composition includes: a base rubber (a); a co-crosslinking agent (b); a crosslinking initiator (c); and an acid and/or a salt (d). The co-crosslinking agent (b) is: (b1) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms; or (b2) a metal salt of an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms.

Abstract: A golf ball 2 includes a spherical core 4 and a cover 6 covering the core 4. The cover 6 includes an inner cover 8 and an outer cover 10 positioned outside the inner cover 8. When distances (%) from a central point of the core 4 to nine points and hardnesses at the nine points, which nine points are obtained by dividing a region from the central point to a surface of the core 4 at intervals of 12.5% of a radius of the core 4, are plotted in a graph, R2 of a linear approximation curve obtained by a least-square method is 0.95 or greater. A hardness of an innermost layer of the cover 6 is greater than a surface hardness of the core 4. Preferably, the core is obtained by a rubber composition being crosslinked. The rubber composition includes an acid and/or a salt (d).

Abstract: The present invention provides a golf ball comprising a spherical core composed of a spherical inner core layer and an outer core layer, an intermediate layer and a cover, wherein the inner core layer has a hardness difference (Hs1-Ho) between a surface hardness (Hs1) and a center hardness (Ho) of 5 or less in JIS-C hardness, the outer core is such that R2 of a linearly approximated curve obtained from a least square method is 0.95 or higher, when JIS-C hardness, measured at nine points obtained by dividing a thickness of the outer core in a radius direction of the spherical core into equal parts having 12.5% intervals therebetween, is plotted against distance (%) from a border point between the outer core layer and the inner core layer, and the intermediate layer has a slab hardness which is greater than a slab hardness of the cover.

Abstract: A golf ball 2 includes a core 4, a mid layer 6, a reinforcing layer 8, an inner cover 10, and an outer cover 12. The core 4 includes a center 18 and an envelope layer 20. The envelope layer 20 is formed by a rubber composition being crosslinked. The rubber composition includes a base rubber, a co-crosslinking agent, a crosslinking initiator, and an acid and/or a salt. The co-crosslinking agent is (1) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms; and/or (2) a metal salt of an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms. A hardness Hc1 of the inner cover is greater than a hardness Hc2 of the outer cover. A thickness T1 of the inner cover is equal to or greater than 0.1 mm but equal to or less than 0.8 mm.

Abstract: A golf ball 2 includes a core 4, a first mid layer 6, a second mid layer 8, and a cover 12. The core 4 includes a center 18 and an envelope layer 20. The center 18 is formed by crosslinking a first rubber composition, and the envelope layer 20 is formed by crosslinking a second rubber composition. The first rubber composition or the second rubber composition includes a base rubber, a co-crosslinking agent, a crosslinking initiator, and an acid and/or a salt. The co-crosslinking agent is: (1) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms; and/or (2) a metal salt of an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms. A hardness Hm2 of the second mid layer 8 is greater than a hardness Hm1 of the first mid layer 6. The hardness Hm2 is greater than a hardness Hc of the cover 12.

Abstract: A golf ball 2 includes a core 4 and a cover 6. The core 4 includes a center 8 and an envelope layer 10 each of which is formed by a rubber composition being crosslinked. At least one of the rubber compositions of the center 8 and the envelope layer 10 includes a base rubber (a), a co-crosslinking agent (b), a crosslinking initiator (c), and an acid and/or a salt (d). The co-crosslinking agent (b) is: (b1) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms; or (b2) a metal salt of an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms. A hardness H(Ie) at an innermost portion of the envelope layer 10 is greater than a hardness H(Sc) at an outermost portion of the center 8. A hardness Ho of the cover 6 is greater than a hardness Hs at a surface of the core 4.

Abstract: An object of the present invention is to provide a golf ball having a novel core structure and traveling a great flight distance on driver shots. The present invention provides a golf ball comprising a core composed of a spherical center and an envelope layer and at least one cover layer disposed outside the core, wherein the spherical center has an internal hardness difference between a maximum hardness and a minimum hardness of less than 5 in JIS-C hardness, the envelope layer is formed from an envelope 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, (c) an crosslinking initiator and (d) an acid and/or a salt thereof, and the outermost cover layer has a highest hardness among the constituent members of the golf ball.

Abstract: A golf ball 2 includes a core 4, amid layer 6, and a cover 10. The core 4 includes a center 16, a first envelope layer 18, and a second envelope layer 20. The first envelope layer 18 is formed by a first rubber composition being crosslinked. The second envelope layer 20 is formed by a second rubber composition being crosslinked. The first rubber composition and/or the second rubber composition include: a base rubber; a co-crosslinking agent; a crosslinking initiator; and an acid and/or a salt. The co-crosslinking agent is (1) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms; and/or (2) a metal salt of an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms.

Abstract: A multiple-piece solid core golf ball includes a solid core including an inner core layer and an outer core layer, and a cover disposed on the outside of the solid core. The inner core layer has an outer diameter of at most approximately 25 mm and is formed of a material having a loss tangent (tan ?) of at least approximately 0.1. The outer core layer is formed of a material having a loss tangent (tan ?) of from approximately 0.01 to approximately 0.1. The difference between the loss tangent (tan ?) of the material forming the inner core layer and the loss tangent (tan ?) of the material forming the outer core layer is at least approximately 0.05.

Abstract: An object of the present invention is to provide a resin composition for the golf ball that suppresses the bleed out of the low molecular weight material component, as well as improves the fluidity and repulsion performance. The present invention provides a golf ball forming resin composition comprising as a resin component, (A) a high melt viscosity resin; (B) a low melt viscosity ionomer resin having a melt viscosity (190° C.) ranging from 1 Pa·s to 10 Pa·s measured by a brookfield viscometer, in a ratio of (A) the high melt viscosity resin/(B) the low melt viscosity ionomer resin being 55 mass % to 99 mass %/45 mass % to 1 mass %; and (C) a metal ion source capable of neutralizing carboxyl groups of (A) the high melt viscosity resin and (B) the low melt viscosity ionomer resin, in an amount of from 0.1 part to 10 parts with respect to 100 parts by mass of a sum of (A) the high melt viscosity resin and (B) the low melt viscosity ionomer resin.

Abstract: A golf ball 2 includes a core 4, an inner cover 6, and an outer cover 8. The core 4 includes a center 10 and an envelope layer 12. The envelope layer 12 is formed by a rubber composition being crosslinked. The rubber composition includes a base rubber (a), a co-crosslinking agent (b), a crosslinking initiator (c), and an acid and/or a salt (d). The co-crosslinking agent (b) is (b1) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms; or (b2) a metal salt of an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms. A hardness Hi of the inner cover 6 is greater than a hardness Hs at a surface of the core 4. A hardness Ho of the outer cover 8 is less than the hardness Hi.