An object of the present invention is to provide a cured product of a golf ball rubber composition capable of imparting excellent durability to a golf ball. The present invention provides a cured product of a golf ball rubber composition, wherein the golf ball rubber composition contains (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, and wherein an effective crosslinking density DC (mmol/cm.sup.3) of the cured product of the golf ball rubber composition and a tensile elastic modulus TM (MPa) between 0.05% strain and 0.25% strain of the cured product of the golf ball rubber composition satisfy a relation of TM3.33In(DC)>(0.10).

A matte colored golf ball which is free of luster and gloss has a good appearance in which injection marks that form during injection molding of a cover layerbe it an intermediate layer or an outermost layerare difficult to see and scuffing on the cover surface is inconspicuous. The golf ball includes a core, an outermost layer, an intermediate layer therebetween, and a coat formed on the surface of the outermost layer. The intermediate layer is formed of a resin composition containing a thermoplastic resin and a colorant consisting of a fluorescent dye or a fluorescent pigment and has a specific visible light transmittance, the outermost layer is molded of a transparent or translucent resin composition that is free of fluorescent dye, and the coat is formed of a urethane-based coating composition containing delustering particles.

An object of the present invention is to provide a golf ball having excellent shot feeling and resilience as well as improved durability and abrasion resistance. The present invention 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 containing (a-1) an ionomer resin and having a material hardness of 58 or less in Shore D hardness; and (B) a polyrotaxane having a cyclodextrin with at least a part of hydroxyl groups thereof being modified with a caprolactone chain having a carboxyl group at a terminal of the caprolactone chain, a linear molecule piercing through a cyclic structure of the cyclodextrin, and blocking groups located at both terminals of the linear molecule to prevent disassociation of the cyclodextrin.

A golf ball includes a main body and a paint layer positioned outside the main body. The paint layer includes an inner layer and an outer layer positioned outside the inner layer. When an indentation depth (nm) is measured on a cross-section along a plane passing through a central point of the golf ball when a force of 30 mgf is applied to the cross-section in a direction perpendicular to the cross-section, an indentation depth Di on a cross-section of the inner layer is smaller than an indentation depth Do on a cross-section of the outer layer. A thickness To of the outer layer is larger than a thickness Ti of the inner layer.

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<0.1X1.30(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).

The golf teaching set in the form of a subconscious habit based on established experience contains a special golf training club no. 0, a swing trainer for learning the position of the striking area at the moment of impact and training golf balls. Training golf club no. 0 has zero loft and the plane of the striking area is reflected in the club's grip. The swing trainer serves to develop the ability to perceive the position of the striking area at the moment of impact. It is used together with training club no. 0, where a pupil tries to achieve clean contact, i.e. under an angle of 0, between the striking area and the area of the flexible panel.

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.

A golf ball strikes a good balance between the durability and the shot feeling, and includes a spherical core and at least one cover disposed outside the spherical core. At least one layer of the cover contains (A) a base resin and (B) a resin fine particle, (A) the base resin contains an ionomer resin, and (B) the resin fine particles contain a polyrotaxane component having a cyclodextrin, a linear molecule penetrating the cyclic structure of the cyclodextrin in a skewering manner, and blocking groups located at both terminals of the linear molecule to prevent disassociation of the cyclodextrin wherein at least a part of hydroxyl groups of the cyclodextrin is modified with a caprolactone chain via a OC.sub.3H.sub.6O group.

A golf ball with a core comprising polybutadiene and graphene, and a soft cover is disclosed herein. The golf ball has a dual core with an outer core comprising polybutadiene and graphene. The soft cover is preferably composed of a highly neutralized polymer, a first ionomer, a second ionomer, and a paraloid impact modifier.

An object of the present invention is to provide a golf ball having excellent approach spin performance under a dry condition and excellent approach spin performance under a condition that there is grass between the golf ball and the club face. 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 composed of at least one layer, and an outermost paint film layer located at the outermost layer of the golf ball contains, as a base resin, a polyurethane obtained by a reaction between (A) a polyisocyanate composition and (B) a polyol composition, (B) the polyol composition contains a urethane polyol as a polyol component, and a loss tangent (tan ) of the outermost paint film layer measured with a dynamic viscoelasticity measuring apparatus under specific conditions has a peak temperature in a range of from 40 C. to 40 C.