Abstract: A golf ball is provided that achieves a satisfactory distance on full shots with a driver and an iron, is superior in the short game, and has a good feel at impact and a good durability. The golf ball has a core formed of a rubber composition as one or more layer, an inner envelope layer formed of a resin material as one or more layer, an outer envelope layer and intermediate layer which are each formed of a resin material as one layer, and a cover formed of a resin material as one layer having a thickness of not more than 1.0 mm. The inner envelope layer-encased sphere, outer envelope layer-encased sphere, intermediate layer-encased sphere and ball have Shore C hardnesses at the respective surfaces thereof which together satisfy certain conditions, and the ball has at least a given deflection under specific loading conditions.

Abstract: In a golf ball having a core, envelope layer, intermediate layer and cover, the (core diameter)/(ball diameter) value falls within a particular range, the core has a specific hardness profile, the intermediate layer is formed primarily of an ionomer resin material including a high-acid ionomer resin, and the Shore C hardness relationships among the core center and surface hardnesses and the surface hardnesses of the envelope layer-encased sphere, intermediate layer-encased sphere and ball satisfy the following conditions: (1) core surface hardness<surface hardness of envelope layer-encased sphere<surface hardness of intermediate layer-encased sphere>ball surface hardness, (2) (surface hardness of envelope layer-encased sphere)?(core center hardness)?28. Also, the intermediate layer and cover have respective thicknesses which satisfy the condition: (3) cover thickness<intermediate layer thickness.

Abstract: A resin composition for golf balls includes (a) an acid-containing copolymer having an amount of acid constituent per 100 wt % of the sum of monomer units in the copolymer that is from 1 to 30 wt %, and (b) an amine-containing polymer having a branched structure. The resin composition imparts golf balls with an excellent rebound resilience and also confers an outstanding durability to repeated impact and an outstanding scuff resistance, making it particularly useful as a cover material in golf balls.

Abstract: A rubber composition for golf balls includes (A) a base rubber, (B) an acrylate ester or methacrylate ester containing an isocyanate group or a blocked isocyanate group, (C) diacrylic acid, dimethacrylic acid or a metal salt thereof, and (D) an organic peroxide. In a golf ball having a core formed of the rubber composition and a cover of one or more layers which encases the core, the rubber composition exhibits a spin rate-lowering effect on shots and can thus improve the flight performance of the ball.

Abstract: In a multi-piece solid golf ball having a core, an intermediate layer encasing the core and a cover which encases the intermediate layer and has numerous dimples on an outside surface thereof, the intermediate layer is formed of a resin material, the cover is formed of a urethane resin material, the core has a diameter of at least 38.0 mm, the core has a deflection when compressed under a final load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf) of at least 3.9 mm, the core has a center and a surface such that the value obtained by subtracting the JIS-C hardness at the core center from the JIS-C hardness at the core surface is at least 15, the sphere obtained by encasing the core with the intermediate layer (intermediate layer-encased sphere) has a surface hardness on the Shore D hardness scale of at least 69, the ball has a surface hardness on the Shore D hardness scale of 62 or less, and the (intermediate layer thickness)/(core diameter) value is from 0.025 to 0.

Abstract: In a multi-piece solid golf ball having a core, an envelope layer, an intermediate layer and a cover, the core, an intermediate layer-encased sphere and the ball have surface hardnesses which satisfy a specific relationship, and the envelope layer, the intermediate layer and the cover have thicknesses which satisfy a specific relationship. Also, the core has a hardness profile in which the hardnesses at the core surface, core center, a position 5 mm from the core center, and a position midway between the surface and center of the core satisfy specific relationships. This golf ball, when used by mid- and high-level amateurs, enables the golfer to maintain an adequate distance on shots with a driver and achieve a good distance on iron shots, has a good spin performance on approach shots and has a good feel on impact. In addition, the ball has an excellent scuff resistance when struck with a grooved wedge.

Abstract: A golf ball of the present disclosure includes an inner ball and a cover layer that covers the outer surface of the inner ball and includes an outer surface with dimples. The inner ball includes an inner layer, which includes an outer surface with a recess, and an inner film that covers only the surface of the recess on the outer surface of the inner layer. The inner layer and the inner film are different colors from each other, and the cover layer is transparent or semi-transparent. Peeling of the film can be suppressed in the golf ball.

Abstract: A golf ball manufacturing method includes an inner layer molding step of molding an inner layer that includes an outer surface with a recess, an inner film formation step, after the inner layer molding step, of coating the outer surface of the inner layer with inner film paint to form an inner film, an inner film removal step, after the inner film formation step, of removing the inner film except for a portion thereof covering a surface of the recess to obtain an inner ball that includes the inner layer and the inner film, and a cover layer molding step, after the inner film removal step, of molding a cover layer that includes an outer surface with dimples on an outer circumferential side of the inner ball to obtain a golf ball. The inner layer and inner film are different colors, and the cover layer is transparent or semi-transparent.

Abstract: A golf ball is provided that includes at least one porous resin layer formed of a resin composition containing a polymeric material and a leachable water-soluble polymer. In a method for producing the golf ball, a resin composition containing the polymeric material and the water-soluble polymer is molded to form a solid molded body, following which the water-soluble polymer is partially leached out and removed. The golf ball has an improved ball controllability on approach shots and an improved feel at impact, maintains a good scuff resistance and has a good moldability.

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 (A) polyurethane or polyurea, and (B) a thermoplastic polyester elastomer. Component (B) is included in a ratio of not more than 45 wt % of the overall amount of the resin composition, and the resin composition has a Shore D hardness of 42 or less and a rebound resilience of from 60 to 72%. The golf ball has an excellent controllability on approach shots, is able to maintain a good feel at impact and a good scuff resistance, and also has a good moldability.

Abstract: A constituent member of a golf ball comprising a vulcanized form of a rubber composition 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, (d) water, (e) an antioxidant which is a benzoimidazole of the following general formula and/or a metal salt thereof, and (g-1) an organosulfur being alkylphenoldisulfide polymers represented by the specific chemical formula or (h) sulfur. When the rubber composition is used in constituent members of a golf ball, especially the core, the golf ball exhibits low spin properties on shots, resulting in an improved flight performance and enabling a good durability to be maintained.

Abstract: In order to satisfy at a high level the golf ball flight and control performances relied on by professional golfers and skilled amateurs, this invention provides a multi-piece solid golf ball G having a core 1, a cover 3 and an intermediate layer 2 therebetween wherein the core is formed of a rubber composition that includes 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. Also, letting Hc be the JIS-C hardness at the center of the core, H12 be the JIS-C hardness at a position 12 mm from the core center and Ho be the JIS-C hardness at the surface of the core, the core has a hardness profile in which these hardnesses satisfy fixed relationships defined by specific formulas.

Abstract: In a golf ball having a core, envelope layer, intermediate layer and cover, the (core diameter)/(ball diameter) value falls within a particular range, the core has a specific hardness profile, and the Shore C hardness relationships among the core center and surface hardnesses and the surface hardnesses of the envelope layer-encased sphere, intermediate layer-encased sphere and ball satisfy the following conditions: core surface hardness<surface hardness of envelope layer-encased sphere<surface hardness of intermediate layer-encased sphere>ball surface hardness,??(1) (surface hardness of envelope layer-encased sphere)?(core center hardness)?28.??(2) Also, the intermediate layer and cover have respective thicknesses which satisfy the condition: cover thickness<intermediate layer thickness.??(3) This ball enables mid-level and skilled amateur golfers to achieve superior distances on driver shots and on iron shots, and moreover has a soft yet good feel at impact.

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, (d) an alcohol and (e-1) an organosulfur, and 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 organosulfur of component (e-1) is alkylphenoldisulfide polymers represented by the specific chemical formula. 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.

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, (d) an alcohol and (f) sulfur, and the amount of component (d) is from 0.1 to 10 parts by weight per 100 parts by weight of the base rubber (a). 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.

Abstract: In a golf ball having a core of one or more layer and a cover of one or more layer encasing the core, the core has a deflection when compressed under a specific load of at least 3.8 mm; at least an innermost portion of the core has a specific difference between maximum and minimum values in cross-sectional hardnesses (JIS-C) from a center to a surface thereof; and the center core is formed of a rubber composition that includes (a) a base rubber, (b) an ?,?-unsaturated carboxylic acid and/or metal salt thereof, (c) a diacyl peroxide and/or a peroxyester, and (d) a dialkyl peroxide and/or a peroxyketal. The golf ball has a low spin rate on driver shots by low head speed golfers, and thus achieves an improved distance, while minimizing any decrease in durability.

Abstract: A golf ball according to the present invention includes: a module including an electronic circuit and its power source; a protective layer that surrounds an outer periphery of the module and is formed from a material having a Shore D hardness of at least 60; a core that surrounds an outer periphery of the protective layer; and a cover that surrounds an outer periphery of the core. A weight may be arranged on a surface of the protective layer. A difference between a value MOImax of the moment of inertia in a direction in which the moment of inertia of the golf ball is maximum and a value MOImin of the moment of inertia in a direction in which the moment of inertia of the golf ball is minimum is at most 1.0 g·cm2.

Abstract: In a golf ball having a core, envelope layer, intermediate layer and cover, the (core diameter)/(ball diameter) value falls within a particular range, the core has a specific hardness profile, and the Shore C hardness relationships among the core center and surface hardnesses and the surface hardnesses of the envelope layer-encased sphere, intermediate layer-encased sphere and ball satisfy the following conditions: core surface hardness<surface hardness of envelope layer-encased sphere<surface hardness of intermediate layer-encased sphere>ball surface hardness,??(1) (surface hardness of envelope layer-encased sphere)?(core center hardness)?28.??(2) Also, the envelope layer, intermediate layer and cover have respective thicknesses which satisfy the condition: cover thickness<intermediate layer thickness envelope layer thickness.

Abstract: In a golf ball having a core, envelope layer, intermediate layer and cover, the (core diameter)/(ball diameter) value falls within a particular range, the core has a specific hardness profile, and the Shore C hardness relationships among the core center and surface hardnesses and the surface hardnesses of the envelope layer-encased sphere, intermediate layer-encased sphere and ball satisfy the following conditions: (1) core surface hardness<surface hardness of envelope layer-encased sphere<surface hardness of intermediate layer-encased sphere>ball surface hardness, (2) (surface hardness of envelope layer-encased sphere)?(core center hardness)?28. Also, the intermediate layer and cover have respective thicknesses which satisfy the condition: (3) cover thickness<intermediate layer thickness. This ball enables mid-level and skilled amateur golfers to achieve superior distances on driver shots and on iron shots, and moreover has a soft yet good feel at impact.

Abstract: In a golf ball having a core, envelope layer, intermediate layer and cover, the (core diameter)/(ball diameter) value falls within a particular range, the core has a specific hardness profile, and the Shore C hardness relationships among the core center and surface hardnesses and the surface hardnesses of the envelope layer-encased sphere, intermediate layer-encased sphere and ball satisfy the following conditions: core surface hardness<envelope layer-encased sphere surface hardness<intermediate layer-encased sphere surface hardness>ball surface hardness, (envelope layer-encased sphere surface hardness)?(core center hardness)?28, and (intermediate layer-encased sphere surface hardness)?(core center hardness)?39. Also, the envelope layer, intermediate layer and cover have thicknesses which satisfy the condition: cover thickness<intermediate layer thickness?envelope layer thickness.