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, wherein the amount of component (d) is from 0.1 to 10 parts by weight per 100 parts by weight of the base rubber (a) and the compounding ratio between component (b) and component (c) is set to at least 60 of E value that is represented by “E=the molar amount of component (b)/the molar amount of the active oxygen of component (c), 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: In a golf ball having a core and a cover of one or more layer, the core is a product molded under heat from a rubber composition which includes (a) a base rubber, (b) a co-crosslinking agent which is an ?,?-unsaturated carboxylic acid and/or a metal salt thereof, (c) an organic peroxide, and (d) water, wherein the content of component (d) is set within a specific range and components (b) and (c) are included in relative amounts that satisfy a specific condition. The core has a specific compressive deformation and a specific hardness difference between the center and surface thereof. Owing to the large hardness difference in the internal hardness profile of the core, the ball exhibits low spin characteristics when hit, improving the flight performance, yet retains a good durability to impact.

Abstract: In a golf ball having a core and a cover of at least one layer encasing the core, the core is formed of a rubber composition which includes (a) a base rubber, (b) a co-crosslinking agent which is an ?,?-unsaturated carboxylic acid and/or a metal salt thereof, (c) a filler, and (d) a crosslinking initiator, and the base rubber (a) has a polybutadiene content of at least 90 wt % and a syndiotactic 1,2-polybutadiene content of from 5 to 30 wt %, the amount of filler (c) included is from 6 to 14 vol % of the rubber composition, and the ball has a specific gravity of 1.0 or more and an initial velocity of 75 m/s or less, as the result of which the golf ball maintains a low rebound, undergoes little change in properties due to changes in temperature and has an excellent durability.

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 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 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: 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: 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: 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 rubber composition for golf balls includes (a) a base rubber, relative amounts of (b) a co-crosslinking agent which is an ?,?-unsaturated carboxylic acid and/or a metal salt thereof and of (c) an organic peroxide that together satisfy a specific condition, and (d) a specific amount of a moisture-providing agent, the latter being a substance which includes on the structure thereof a water constituent other than free water and eliminates moisture under heating or a substance which thermally decomposes under heating, releasing a water constituent. When the hardness difference in the internal hardness profile of a golf ball core made of the composition is large, the ball exhibits a low spin rate on shots, improving the flight performance of the ball, and the durability of the ball to cracking is enhanced.

Abstract: A rubber composition for golf balls is provided which, when the hardness difference in the internal hardness profile of a golf ball core made of the composition is set to a large value, enables the ball to exhibit low spin characteristics when hit, improving the flight performance of the ball, and also enhances the ball durability to cracking. The rubber composition includes (a) a base rubber, (b) a co-crosslinking agent that is an ?,?-unsaturated carboxylic acid and/or a metal salt thereof, (c) an organic peroxide and (d) water, component (d) being included in an amount of from 0.1 to 10 parts by weight per 100 parts by weight of component (a), and components (b) and (c) being included in relative amounts such that E, defined by the formula E=molar amount of component (b)/molar amount of active oxygens in component (c), has a value of 93 or more.

Abstract: The present invention provides a rubber composition for golf balls which includes (a) a base rubber, (b) a co-crosslinking agent being an ?,?-unsaturated carboxylic acid and/or a metal salt thereof, (c) a crosslinking initiator and (d) a specific amount of an anionic surfactant, so that the rubber composition reduces sticking of a molded rubber material made therefrom to the mold and also maintains the resilience and other properties of the molded rubber material.

Abstract: In a golf ball having a core and a cover of one or more layer, the core is a product molded under heat from a rubber composition which includes (a) a base rubber, (b) a co-crosslinking agent which is an ?,?-unsaturated carboxylic acid and/or a metal salt thereof, (c) an organic peroxide, and (d) water, wherein the content of component (d) is set within a specific range and components (b) and (c) are included in relative amounts that satisfy a specific condition. The core has a specific compressive deformation and a specific hardness difference between the center and surface thereof. Owing to the large hardness difference in the internal hardness profile of the core, the ball exhibits low spin characteristics when hit, improving the flight performance, yet retains a good durability to impact.

Abstract: A golf ball made up of components such as a coating layer, a cover layer, an intermediate layer and a core includes, within such a component, a material that contains a phase-change material. The phase-change material is preferably normal paraffin having a melting point of between 5° C. and 40° C. and is preferably used in the form of microcapsules. This golf ball suppresses changes in the ball temperature itself in response to changes in the ambient air temperature during use of the ball, enabling the optimal properties that have been designed into the ball to be maintained.

Abstract: A rubber composition for a golf ball core includes (a) a conjugated diene polymer, (b) a copolymer of a conjugated diene compound and a non-conjugated olefin, and (c) an organic peroxide. Golf balls having at least one core layer formed of such a rubber composition and a cover of one or more layers encasing the core exhibit improved durability to cracking on repeated impact while maintaining the basic properties required of golf balls, such as flight and spin controllability on approach shots.

Abstract: A rubber composition for a golf ball core includes (a) a conjugated diene polymer, (b) a multi-component copolymer having conjugated diene units, non-conjugated olefin units and aromatic vinyl units, and (c) an organic peroxide. The conjugated diene units include butadiene units, the non-conjugated olefin units include ethylene units, and the aromatic vinyl units include styrene units. The content of conjugated diene units with respect to the multi-component copolymer is at least 5 wt %. Golf balls having at least one core layer formed of such a rubber composition and a cover of one or more layers encasing the core exhibit improved durability to cracking on repeated impact while maintaining the basic properties required of golf balls, such as flight and spin controllability on approach shots.

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, wherein the amount of component (d) is from 0.1 to 10 parts by weight per 100 parts by weight of the base rubber (a) and the compounding ratio between component (b) and component (c) is set to at least 60 of E value that is represented by “E=the molar amount of component (b)/the molar amount of the active oxygen of component (c), 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: 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: 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 rubber composition for golf balls includes (a) a base rubber, (b) a co-crosslinking agent which is an ?,?-unsaturated carboxylic acid and/or a metal salt thereof, (c) a crosslinking initiator, and (d) an alcohol having a value obtained by dividing the molecular weight of the alcohol by the number of hydroxyl groups thereon which is 70 or less. When the rubber composition is used in a golf ball having a core and a cover of one or more layers encasing the core, by setting the hardness difference in the core interior hardness profile to a large value while maintaining a desired core hardness, low spin properties can be manifested on golf ball shots, enabling the flight performance of the ball to be improved.