Abstract: An object of the present disclosure is to provide a golf ball having good shot feeling and excellent durability and not having lowered resilience even if a hard cover material is used. The present disclosure provides a golf ball comprising a spherical core, and a cover disposed outside the spherical core and composed of one or more layers, wherein at least one cover layer contains (A) a base resin, and (B) at least one member selected from the group consisting of a polyrotaxane, a polyethylene oxide, a polypropylene oxide, a polycaprolactone and a liquid polymer, and Sa×Spc?100 wherein Sa (?m) is an arithmetic mean roughness of a surface of a cut plane of the cover, and Spc (mm?1) is an arithmetic mean curvature of a summit of the surface of the cut plane of the cover.

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 disclosure is to provide a golf ball having good shot feeling and excellent durability while having non-lowered resilience. The present disclosure provides a golf ball comprising a spherical core and one or more cover layers disposed outside the spherical core, wherein at least one layer of the cover layers contains (A) a base resin and (B) a polyethylene oxide.

Abstract: An object of the present invention is to provide a golf ball having excellent shot feeling while maintaining the resilience performance on driver shots. The present invention provides a golf ball comprising a core and at least one cover 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 monophenol compound having a substituent group only at p-position.

Abstract: An object of the present invention is to provide a novel golf ball having excellent spin performance on approach shots. 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 and composed of at least one layer, wherein a base resin constituting an outermost layer of the paint film includes a polyurethane, and the polyurethane has a loss elastic modulus (E?) of 0.2×108 Pa or more at ?50° C. and a loss tangent (tan ?) having a peak temperature of 0° C. or less, obtained by measuring dynamic viscoelasticity of the polyurethane under specific conditions.

Abstract: An object of the present disclosure is to provide a golf ball having good shot feeling and excellent durability and not having lowered resilience even if a hard cover material is used. The present disclosure provides a golf ball comprising a spherical core, and a cover disposed outside the spherical core and composed of one or more layers, wherein at least one cover layer contains (A) a base resin, and (B) at least one member selected from the group consisting of a polyrotaxane, a polyethylene oxide, a polypropylene oxide, a polycaprolactone and a liquid polymer, and Sa×Spc?100 wherein Sa (?m) is an arithmetic mean roughness of a surface of a cut plane of the cover, and Spc (mm?1) is an arithmetic mean curvature of a summit of the surface of the cut plane of the cover.

Abstract: An object of the present invention is to provide a golf ball having excellent color development stability. 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, and the fluorescent pigment has a number-based cumulative median size of 2.5 ?m or more.

Abstract: An object of the present invention is to provide a golf ball having excellent durability and good shot feeling. The present invention provides a golf ball comprising a core, wherein a difference (crosslinking density at surface of core-crosslinking density at center of core) between a crosslinking density at a surface of the core and a crosslinking density at a center of the core is more than 1.0×102 mol/m3 and less than 9.0×102 mol/m3, and a hardness difference (Hs?Ho) between Hs and Ho is 13.0 or more and 30.0 or less, and the core satisfies H50?Ho>Hs?H50, wherein Hs (Shore C hardness) is a hardness at the surface of the core, Ho (Shore C hardness) is a hardness at the center of the core, and H50 (Shore C hardness) is a hardness at a midpoint between the center of the core and the surface of the core.

Abstract: An object of the present disclosure is to provide a rubber composition from which a crosslinked rubber molded product having good softness and excellent resilience performance can be obtained. The present disclosure provides a 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 benzothiazole derivative, and further comprising (e) a metal compound when (b) the co-crosslinking agent consists of the ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms, wherein (d) the benzothiazole derivative is a compound represented by the formula (1) and/or a compound represented by the formula (2).

Abstract: An object of the present invention is to provide a golf ball having a decreased spin rate on driver shots. 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 the formula (1) as a co-crosslinking agent, and (c) a crosslinking initiator, (R1COO)M(OCOR2)m??(1) in the formula (1), M represents a metal atom, m represents 1 or 2, R1 and R2 are different from each other, represent an alkenyl group having 2 to 30 carbon atoms or an alkynyl group having 2 to 30 carbon atoms and have a carbon-carbon double bond or a carbon-carbon triple bond at an ?-position carbon atom bonding to the carbonyl group, and when m is 2, two of R2 may be identical to or different from each other.

Abstract: An object of the present invention is to provide a golf ball having a decreased spin rate on driver shots. 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) two or more ?,?-unsaturated carboxylic acids having 3 to 14 carbon atoms and having no substituent group at a carbon atom bonding to the carboxy group, and/or a metal salt thereof, and (c) a crosslinking initiator.

Abstract: An object of the present disclosure is to provide a rubber composition from which a crosslinked rubber molded product having good softness and excellent resilience performance can be obtained. The present disclosure provides a rubber composition containing (a) a base rubber, (b) a co-crosslinking agent, (c) a crosslinking initiator, and (d) a salt of a benzothiazole derivative, wherein (d) the salt of the benzothiazole derivative includes a compound represented by the formula (1) in which a sulfur atom S2 constituting a thiocarbonyl group has a Mulliken charge of ?0.190 or more. [In the formula (1), R1 to R4 are identical to or different from each other, and represent an electron-withdrawing group or a hydrogen atom, S1 and S2 represent a sulfur atom, X represents a cation component, n is an integer ranging from 1 to 4, and at least one of R1 to R4 bonding to the identical benzene ring is an electron-withdrawing group when n is 2 or more.

Abstract: An object of the present invention is to provide a golf ball having excellent durability and good shot feeling. The present invention provides a golf ball comprising a core, wherein a difference (crosslinking density at surface of core-crosslinking density at center of core) between a crosslinking density at a surface of the core and a crosslinking density at a center of the core is more than 1.0×102 mol/m3 and less than 9.0×102 mol/m3, and a hardness difference (Hs?Ho) between Hs and Ho is 13.0 or more and 30.0 or less, and the core satisfies H50-Ho>Hs-H50, wherein Hs (Shore C hardness) is a hardness at the surface of the core, Ho (Shore C hardness) is a hardness at the center of the core, and H50 (Shore C hardness) is a hardness at a midpoint between the center of the core and the surface of the core.

Abstract: An object of the present invention is to provide a golf ball having excellent durability and good shot feeling. The present invention provides a golf ball comprising a core, wherein a difference (crosslinking density at surface of core?crosslinking density at center of core) between a crosslinking density at a surface of the core and a crosslinking density at a center of the core is more than 1.0×102 mol/m3 and less than 9.0×102 mol/m3, and a hardness difference (Hs?Ho) between Hs and Ho is 13.0 or more and 30.0 or less, and the core satisfies H50?Ho>Hs?H50, wherein Hs (Shore C hardness) is a hardness at the surface of the core, Ho (Shore C hardness) is a hardness at the center of the core, and H50 (Shore C hardness) is a hardness at a midpoint between the center of the core and the surface of the core.

Abstract: An object of the present invention is to provide a dithioester compound generating an aralkyloxy radical having high ability of abstracting hydrogen. The present invention provides a dithioester compound represented by a formula (1). In the formula (1), R1 and R2 each independently represent an alkyl group having 1 or more carbon atoms, an alkenyl group having two or more carbon atoms, an alkynyl group having two or more carbon atoms, an aryl group having 6 or more carbon atoms and optionally having a substituent group, an aralkyl group having 6 or more carbon atoms, a hydrogen atom, or a halogen atom; R3 represents an aryl group having 6 or more carbon atoms and optionally having a substituent group, or an aralkyl group having 6 or more carbon atoms and optionally having a substituent group.

Abstract: An object of the present invention is to provide a golf ball having excellent shot feeling while maintaining the resilience performance on driver shots. The present invention provides a golf ball comprising a core and at least one cover 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 monophenol compound having a substituent group only at p-position.

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 novel golf ball having excellent spin performance on approach shots. 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 and composed of at least one layer, wherein a base resin constituting an outermost layer of the paint film includes a polyurethane, and the polyurethane has a loss elastic modulus (E?) of 0.2×108 Pa or more at ?50° C. and a loss tangent (tan ?) having a peak temperature of 0° C. or less, obtained by measuring dynamic viscoelasticity of the polyurethane under specific conditions.

Abstract: An object of the present invention is to provide a golf ball having oily stain washability or weed juice stain resistance that is adjustable depending on a temperature. The present invention provides a golf ball comprising a golf ball body and a paint film composed of at least one layer and covering the golf ball body, wherein a molecular chain of a base resin constituting an outermost layer located at an outermost side of the paint film has a graft chain, and 80 mole % or more of repeating units constituting the graft chain includes any one of repeating units represented by formulae (1) to (4): [In the formulae (1) to (4), R1 to R5 each independently represent hydrogen, halogen or an organic group.

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.