Abstract: A golf club head having a volume of from 400 cc through 460 cc includes: a face portion that includes a face surface that is to be a striking surface; and a body portion that includes carbon fiber-reinforced plastics. The body portion includes a sole portion, a crown portion, and a weight member attached to the sole portion at an inner-surface side thereof. The weight member includes a first weight member that is disposed directly below a center of gravity of the golf club head, and a second weight member that extends from the first weight member in a toe-heel direction.

Abstract: A golf ball includes a core and a cover, in which the core is formed in a single layer of a rubber composition, the cover is formed of a resin composition, a hardness profile of the core has a specific cross-sectional hardness profile, and letting a deflection (mm) when the core is compressed under a final load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf) be C (mm), a Shore C hardness at a core center be Cc, and a Shore C hardness at a core surface be Cs, the following condition is satisfied: C × ( Cs - Cc ) ? 1 ? 3 ? 2 . 0 .

Abstract: In a golf ball having a core and a cover of one or more layer, the core is formed of a material molded under heat from a rubber composition containing (a) a base rubber, (b) water and/or a lower alcohol having a specific molecular weight, (c) an ?,?-unsaturated carboxylic acid and/or a metal salt thereof, and (d) an organic peroxide. The base rubber (a) is a rubber obtained by mixing together (a-1) a polybutadiene and (a-2) an unneutralized ethylene-unsaturated carboxylic acid copolymer, and subsequently neutralizing the copolymer with (a-3) a metal oxide. Component (a-2) has a specific acid content and accounts for a specific portion of the combined amount of components (a-1) and (a-2). The difference in crosslink density between the core center and the core surface, expressed as (crosslink density of core surface)?(crosslink density of core center), is at least 5.0×102 mol/m3.

Abstract: In a golf ball having a rubber core of at least one layer and a cover of at least one layer encasing the core, at least one layer of the cover is formed of a resin composition that includes (I) a polyurethane or a polyurea and (II) an aromatic vinyl elastomer, the amount of component (II) included per 100 parts by weight of component (I) is less than 15 parts by weight, and the CS1 value calculated by formula (1) below C ? S 1 = ( C ? V 5 ? 0 - C ? V 1 ? 2 ) / 38 ( 1 ) (wherein CV50 is the coefficient of restitution at an incident velocity of 50.0 m/s and CV12 is the coefficient of restitution at an incident velocity of 12.0 m/s) is larger than ?4.08×10?3, so that the golf ball has both an excellent controllability and a good feel at impact on approach shots together with a good scuff resistance.

Abstract: The present invention provides a multi-piece solid golf ball including a core, a surrounding layer, an intermediate layer, and a cover, in which a large number of dimples are formed on an outside surface of the cover, the core is formed of a single layer or a plurality of layers of a rubber composition, the surrounding layer is formed of a single layer or a plurality of layers of a resin composition, the intermediate layer and the cover are both formed of a single layer of a resin composition, and a relationship between an initial velocity of an intermediate layer-encased sphere and an initial velocity of the ball satisfies the following condition: (initial velocity of ball)<(initial velocity of intermediate layer-encased sphere). Further, a deflection of the ball under a predetermined load is optimized, and a lift coefficient and a drag coefficient at a predetermined Reynolds number and spin rate of the dimples are set within a predetermined range.

Abstract: In a golf ball having a core and a cover of at least one layer encasing the core, at least one layer of the cover is formed of a resin composition which includes (I) a polyurethane or a polyurea, and (II) a core-shell polymer in which the core is a crosslinked acrylic rubber particle and the shell consists of an acrylic polymer, the amount of component (II) included per 100 parts by weight of component (I) is less than 15 parts by weight, and the CS1 value calculated by formula (1) below CS1=(CV50?CV12)/38??(1) (wherein CV50 is the coefficient of restitution at an incident velocity of 50.0 m/s and CV12 is the coefficient of restitution at an incident velocity of 12.0 m/s) is larger than ?4.08×10?3, thereby to have an excellent controllability, a good feel at impact on approach shots and a good scuff resistance.

Abstract: A golf ball includes a core, an intermediate layer, and a cover, in which an initial velocity is not more than 76.0 m/s, a deflection when the ball is compressed under a specific load is at least 2.8 mm, and letting a value of (initial velocity of core×weight of core) be Ciw, a value of [(initial velocity of intermediate layer-encased sphere?initial velocity of core)×(weight of intermediate layer-encased sphere?weight of core)] be Miw, and a value of [(initial velocity of ball?initial velocity of intermediate layer-encased sphere)×(weight of ball?weight of intermediate layer-encased sphere)] be CViw, the condition is of Ciw+Miw+CViw?2,550 is satisfied, thereby to be capable of making a distance for reducing a distance on shots with a driver and an iron by average hitters smaller.

Abstract: The present invention provides a golf ball in which a large number of dimples are formed on a ball surface, and when edge angles at points where depths are 10%, 20%, and 30% in a cross-section of one dimple are denoted by ED1, ED2, and ED3, respectively, dimples having a cross-sectional shape satisfying the following condition (1): ED1<ED2>ED3??(1) account for at least 10% of a total number of the dimples.

Abstract: In a golf ball having a core, a cover and at least one intermediate layer formed therebetween, the core, intermediate layer and cover have respective specific gravities with a standard deviation of not more than 0.07 or less, the cover has a material hardness on the Shore D hardness scale of 52 or less, and the ball has a deflection when compressed under a final load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf) which is 2.8 mm or less. The amount of deviation in the ball center of gravity is exceedingly small, increasing the straightness with which the ball rolls on putts with a putter.

Abstract: The present invention provides a golf ball comprising a core of one or more layers and a cover of one or more layers which encases the core, wherein at least one layer of the cover is formed of the resin composition comprising (a?) a polyester resin and (b) an amine-containing polymer having a branched structure. In the golf ball of the present invention, the adhesion property between the core and each cover layer adjacent to the core can be improved and the excellent durability can be obtained.

Abstract: In a golf ball having a core, a cover, at least one intermediate layer therebetween, and a coating layer on the cover, the cover is formed of a transparent or translucent resin composition and the intermediate layer is formed of a resin composition. The sphere consisting of the core encased by the intermediate layer has specific lightness and chroma values in the Lab color space. The coating layer is composed of one or more layer, at least one of which contains an effect pigment having polarizing properties. Markings are provided inside of the coating layer and have a specific L value. During use, the ball retains a visual to familiarity close to that of a white ball. Up close, it is clearly discernible from a white ball; from a distance, it appears white and is highly visible.

Abstract: The present invention provides a golf ball including a two-layer core having an inner layer core and an outer layer core, an intermediate layer, and a cover, in which a large number of dimples are formed on an outer surface of the cover, and a relationship between a surface hardness of an intermediate layer-encased sphere and a ball surface hardness satisfies the following condition: (ball surface hardness)< (surface hardness of intermediate layer-encased sphere) (where hardness means Shore D hardness). Further, a value obtained by subtracting a center hardness of the entire core from a surface hardness of the entire core is at least 25 on the Shore C hardness scale, and a lift coefficient and a drag coefficient at a predetermined Reynolds number and spin rate of the dimples are set within a predetermined range.

Abstract: In a golf ball having a core and a cover of one or more layer, the core is formed of a material molded under heat from a rubber composition containing (a) a base rubber, (b) water and/or a lower alcohol having a specific molecular weight, (c) an ?,?-unsaturated carboxylic acid and/or a metal salt thereof, and (d) an organic peroxide. The base rubber (a) is a rubber obtained by mixing together (a-1) a polybutadiene and (a-2) an unneutralized ethylene-unsaturated carboxylic acid copolymer, and subsequently neutralizing the copolymer with (a-3) a metal oxide. Component (a-2) has a specific acid content and accounts for a specific portion of the combined amount of components (a-1) and (a-2). The core surface and center have a specific JIS-C hardness difference therebetween. This ball achieves both a lower spin rate and excellent durability while maintaining a high rebound.

Abstract: The present invention provides a multi-piece solid golf ball including a core, an intermediate layer, and a cover, in which a large number of dimples are formed on an outside surface of the cover, and a relationship between a cover material hardness and a midpoint hardness (Cm) between a core surface and a core center satisfies the following condition: midpoint hardness (Cm) between core surface and core center>cover material hardness where hardness means Shore C hardness. Further, a surface hardness of the ball is optimized, a deflection of the ball when compressed under a predetermined load is optimized, and a lift coefficient and a drag coefficient at a predetermined Reynolds number and spin rate of the dimples are set within a predetermined range.

Abstract: The present invention provides the rubber composition for a golf ball comprising (a) a base rubber, (b) a co-crosslinking agent which is an ?,?-unsaturated carboxylic acid or a metal salt thereof or both, (c) a crosslinking initiator, and (d) an alcohol, in which further (e) a hindered phenol-type antioxidant including a substituent having thioether structure is included and the content of component (e) is at least 0.2 part by weight per 100 parts by weight of component (a), and a golf ball using the rubber composition, in order to achieve the object that good durability of the golf ball to impact is maintained.

Abstract: The invention provides a rubber composition for golf balls, comprising: (a) a base rubber, (b) a co-crosslinking agent which is an ?,?-unsaturated carboxylic acid or a metal salt thereof or both, (c) an organic peroxide, (d) water or a moisture-providing agent, (e) a hindered phenol-type antioxidant including a substituent having thioether structure, wherein the content of component (e) is at least 0.2 part by weight per 100 parts by weight of component (a).

Abstract: A multilayer core molding method includes: an upstream process of obtaining an intermediate molded body 33; and a downstream process of performing molding using a downstream process molding apparatus 2, and wherein the downstream process includes: an intermediate molded body arrangement step of arranging the intermediate molded body on the intermediate plate cavity surface or the first downstream process mold cavity surface; and a first vulcanization step, performed after the intermediate molded body arrangement step, of vulcanization-molding the intermediate molded body until it is substantially or completely vulcanized, in a state in which at least the first downstream process mold and the intermediate plate are closed against each other.

Abstract: A golf club head includes a first groove formed in a face portion of the head, and a second groove formed in the face portion and intersecting the first groove. A first protrusion is formed along an edge of the first groove. A second protrusion is formed along an edge of the second groove. A third protrusion is formed at an edge of an intersection between the first groove and the second groove, the third protrusion being higher than the first protrusion and the second protrusion.

Abstract: In a golf ball having a core composed of one or more layer, the outermost layer of the core is formed of a rubber composition containing an ?,?-unsaturated metal carboxylate, and an envelope layer directly encasing the core is formed of a resin composition containing a thermoplastic resin having a structure that includes ?,?-ethylenically unsaturated carboxylic acid copolymerization units. The infrared absorption spectra at surface sites on the outermost layer of the core, as measured by ATR FT-IR spectroscopy, satisfy a specific condition. The ball has an enhanced adhesion between the rubber-based core and the adjacent cover layer that is formed of an ionomer resin or other ?,?-ethylenically unsaturated carboxylic acid copolymer-containing resin material.

Abstract: A multi-piece solid golf ball includes a core, an intermediate layer, and a cover, in which the core is formed of a rubber composition, the intermediate layer and the cover are formed of a single-layer resin composition, and a relationship among an initial velocity of the core, an initial velocity of an intermediate layer-encased sphere, and an initial velocity of a sphere (ball) obtained by encasing the intermediate layer-encased sphere with the cover satisfies (ball initial velocity)<(initial velocity of intermediate layer-encased sphere) and 0.60?(initial velocity of intermediate layer-encased sphere)?(core initial velocity)?0.90 (m/s). When each sphere of the core and the ball is compressed under a specific load and deflections are denoted by C (mm) and B (mm), respectively, a value of C?B is not more than 1.10 mm, and 0.024?(intermediate layer thickness)/(ball diameter)?0.034 is satisfied.