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: An object of the present invention is to provide a golf ball having excellent durability. The present invention provides a golf ball comprising a core and at least one cover layer covering the core, wherein the core is formed from a core 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) a crosslinking initiator, and (d) a hindered phenol compound, and (b) the co-crosslinking agent and (d) the hindered phenol compound are blended in the core rubber composition such that the following expression (1) is satisfied: 0.04?HF/B?0.35??(1) in the formula (1), HF=a number of OH functional group in one molecule of (d) the hindered phenol compound×an amount of (d) the hindered phenol compound (mole) with respect to 100 parts by mass of (a) the base rubber, and B=an amount of (b) the co-crosslinking agent (mole) with respect to 100 parts by mass of (a) the base rubber.

Abstract: An object of the present invention is to provide a golf ball traveling a great flight distance and having a good shot feeling on long iron shots. The present invention provides a golf ball comprising a core, at least one intermediate layer covering the core and a cover covering the intermediate layer, wherein the core is formed from a core rubber composition containing (a) a base rubber containing a polybutadiene, (b) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, (c) a crosslinking initiator, and (d) a terpene-based resin, and a material hardness (Hm) of the intermediate layer is higher than a material hardness (Hc) of the cover, and the material hardness (Hc) of the cover is less than 50 in Shore D hardness.

Abstract: An object of the present invention is to provide a golf ball traveling a great flight distance and having a good shot feeling on long iron shots. The present invention provides a golf ball comprising a core, at least one intermediate layer covering the core and a cover covering the intermediate layer, wherein the core is formed from a core rubber composition containing (a) a base rubber containing a polybutadiene, (b) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, (c) a crosslinking initiator, and (d) a terpene-based resin, and a material hardness (Hm) of the intermediate layer is higher than a material hardness (Hc) of the cover, and the material hardness (Hc) of the cover is 50 or more in Shore D hardness.

Abstract: An object of the present invention is to provide a golf ball traveling a great flight distance and having a good shot feeling and durability on driver shots. The present invention provides a golf ball comprising a core, at least one intermediate layer covering the core and a cover covering the intermediate layer, wherein the core is formed from a core rubber composition containing (a) a base rubber containing a polybutadiene, (b) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, (c) a crosslinking initiator, and (d) a terpene-based resin, and a material hardness (Hm) of the intermediate layer and a material hardness (Hc) of the cover satisfy an equation of Hm?Hc.

Abstract: An object of the present invention is to provide a golf ball having excellent durability. The present invention provides a golf ball comprising a spherical core composed of an inner core layer and an outer core layer, and at least one cover covering the spherical core, wherein the inner core layer is formed from an inner core layer 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) a crosslinking initiator, and (d) a terpene-based resin.

Abstract: An object of the present invention is to provide a golf ball having excellent spin performance on approach shots under a dry condition and excellent spin performance on approach shots under the condition that there is grass between the golf ball and the club face. The present invention provides golf ball comprising a golf ball body and a paint film formed on a surface of the golf ball body, wherein the paint film has a multi-layered construction composed of two or more layers, a ratio (M1/E1) of a 10% elastic modulus (kgf/cm2) (M1) of an innermost layer of the paint film to a maximum elongation (%) (E1) of the innermost layer of the paint film is 10 or more and 50 or less, and the ratio (M1/E1) of the innermost layer of the paint film is greater than a ratio (M2/E2) of a 10% elastic modulus (kgf/cm2) (M2) of an outermost layer of the paint film to a maximum elongation (%) (E2) of the outermost layer of the paint film.

Abstract: An object of the present invention is to provide a golf ball having excellent shot feeling on driver shots. The present invention provides a golf ball comprising a core and at least one cover covering the core, wherein a material for forming the core has a loss tangent difference ? tan ? (tan ??80?tan ??40) of 0.12 or more between a loss tangent tan ??80 at ?80° C. and a loss tangent tan ??40 at ?40° C.

Abstract: A golf ball including a core and a cover covering the core, wherein the cover is formed from a cover resin composition containing a first base resin and a fluorescent pigment, the first base resin contains at least one resin selected from the group consisting of a polyurethane resin, an ionomer resin and a polyamide resin, the fluorescent pigment is a dispersion having a fluorescent dye dispersed in a second base resin, and the second base resin contains at least one resin selected from the group consisting of a benzoguanamine resin, an acrylic resin and a polyester resin, and a constituent member of the golf ball other than the cover does not contain a fluorescent pigment and/or a fluorescent dye.

Abstract: An object of the present invention is to provide a golf ball having excellent spin performance on approach shots under a dry condition and excellent spin performance on approach shots under the condition that there is grass between the golf ball and the club face. The present invention provides golf ball comprising a golf ball body and a paint film formed on a surface of the golf ball body, wherein the paint film has a multi-layered construction composed of two or more layers, a ratio (M1/E1) of a 10% elastic modulus (kgf/cm2) (M1) of an innermost layer of the paint film to a maximum elongation (%) (E1) of the innermost layer of the paint film is 10 or more and 50 or less, and the ratio (M1/E1) of the innermost layer of the paint film is greater than a ratio (M2/E2) of a 10% elastic modulus (kgf/cm2) (M2) of an outermost layer of the paint film to a maximum elongation (%) (E2) of the outermost layer of the paint film.

Abstract: An object of the present invention is to provide a golf ball comprising a cover excellent in color development over a long period of time. The present invention provides a golf ball comprising a core and a cover covering the core, wherein the cover is formed from a resin composition containing a first base resin and a fluorescent pigment, the fluorescent pigment is a dispersion having a fluorescent dye dispersed in a second base resin, and an absolute value (|SP1?SP2|) of a difference between a solubility parameter value (SP1) ((cal/cm3)0.5) of the first base resin and a solubility parameter value (SP2) ((cal/cm3)0.5) of the second base resin is 6 or less.

Abstract: An object of the present invention is to provide a golf ball comprising a cover excellent in color development over a long period of time. The present invention provides a golf ball comprising a core and a cover covering the core, wherein the cover is formed from a resin composition containing a first base resin and a fluorescent pigment, the fluorescent pigment is a dispersion having a fluorescent dye dispersed in a second base resin, and an absolute value (|SP1?SP2|) of a difference between a solubility parameter value (SP1) ((cal/cm3)0.5) of the first base resin and a solubility parameter value (SP2) ((cal/cm3)0.5) of the second base resin is 6 or less.

Abstract: An object of the present invention is to provide a golf ball excellent in resilience performance. The present invention provides a golf ball comprising a spherical core and at least one cover layer covering the spherical core, wherein the spherical core is formed from a rubber composition containing (a) a base rubber, (b) a compound represented by a formula (1) as a co-crosslinking agent and (c) a crosslinking initiator. (R1OCO)M(COOR2)m??(1) [In the formula (1), M represents a metal atom, R1 and R2 represent an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms, and m represents 1 or 2.