Abstract: A golf ball material contains (i) fine particles that have an average particle size of less than 300 ?m and are composed of a crosslinked multi-component copolymer having conjugated diene units, non-conjugated olefin units and aromatic vinyl units; and (ii) a thermoplastic resin. The conjugated diene units include butadiene units, the non-conjugated olefin units include units selected from the group consisting of ethylene, propylene and 1-butene units, the aromatic vinyl units include styrene units, and the content of the conjugated diene units in the multi-component copolymer is 5 wt % or more. This golf ball material is soft, has an excellent rebound resilience and also has a good processability.

Abstract: In a golf ball having a two-layer core which includes an inner core layer and an outer core layer and having a cover of one or more layer, the outer core layer is formed of an elastomer composition that includes specific amounts of (A) polybutadiene having a 1,2-bond content of 50 to 95%, (B) a photocurable monomer, oligomer or polymer, and (C) a photopolymerizable initiator. The outer core layer has a thickness of from 1.0 to 4.0 mm, and the two-layer core has a surface hardness on the JIS-C scale of from 75 to 95. The ball is provided with a hardness gradient at the core interior, which lowers the spin rate of the ball, has an improved durability to cracking, and production costs for the outer core layer are kept relatively low.

Abstract: A golf ball having a cover with a plurality of dimples on the surface thereof is provided with a coat of mutually differing properties on dimple areas of the surface and on land areas between the dimples. The land areas are formed with a coat having a high coefficient of friction and the dimple areas have a surface energy of not more than 32 dynes, enabling a lower spin rate to be achieved and thus increasing the distance traveled by the ball, particularly when struck with a middle iron, and also help impart a high spin rate and a good controllability on approach shots.

Abstract: In a golf ball having a core and a cover, the cover is formed primarily of polyurethane, the ball has a weight of 44.8 g or less and, in an impact test carried out by hitting the ball with a driver at a head speed of 40 m/s, the sum t1+t2 of the time t1 required from initial contact by the driver with the ball for deformation of the ball to reach a maximum and the time t2 required from the state of maximum ball deformation for the ball and driver to separate is 650 ?sec or less. This golf ball makes it possible for golfers who have a high head speed and ordinary golfers who do not to compete without relying excessively on superiority in terms of distance.

Abstract: In a golf ball having a core and a cover with a plurality of dimples on the surface, the cover is formed primarily of polyurethane, the dimples have a specific volume occupancy ratio and the ball has a diameter of at least 42.8 mm. In an impact test carried out by hitting the ball with a driver at a head speed of 40 m/s, the sum t1+t2 of the time t1 required from initial contact by the driver with the ball for deformation of the ball to reach a maximum and the time t2 required from the state of maximum ball deformation for the ball and driver to separate is 660 ?sec or less. This golf ball makes it possible for golfers who have a high head speed and ordinary golfers who do not to compete without relying excessively on superiority in terms of distance.

Abstract: In a golf ball having a core and a cover, the cover is formed primarily of polyurethane, the ball has a diameter of at least 43.0 mm and, in an impact test carried out by hitting the ball with a driver at a head speed of 40 m/s, the sum t1+t2 of the time t1 required from initial contact by the driver with the ball for deformation of the ball to reach a maximum and the time t2 required from the state of maximum ball deformation for the ball and driver to separate is 650 ?sec or less. This golf ball makes it possible for golfers who have a high head speed and ordinary golfers who do not to compete without relying excessively on superiority in terms of distance.

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 material contains (I) a multi-component copolymer having conjugated diene units, non-conjugated olefin units and aromatic vinyl units; and (II) a binary copolymer of an olefin and an ?,?-unsaturated carboxylic acid of 3 to 8 carbons and/or a ternary copolymer of an olefin, an ?,?-unsaturated carboxylic acid of 3 to 8 carbons and an ester of the ?,?-unsaturated carboxylic acid, or a metal neutralization product thereof. The conjugated diene units include butadiene units, the non-conjugated olefin units include units selected from the group consisting of ethylene, propylene and 1-butene units, and the aromatic vinyl units include styrene units. The content of the conjugated diene units in the multi-component copolymer (I) is 5 wt % or more. This golf ball material is soft and has an excellent rebound resilience. Golf balls which use this material in the cover provide golfers with a competitive edge.

Abstract: A golf club head includes a face portion, a plurality of score lines formed in the face portion and extending in a toe-heel direction, a plurality of convex portions formed in the face portion and extending in the toe-heel direction between the score lines adjacent to each other in a vertical direction of the face portion, and at least one concave portion formed in the face portion and extending in the toe-heel direction between the convex portions adjacent to each other in the vertical direction. A flat surface is formed between the concave portion and the convex portion adjacent to the concave portion.

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.

Abstract: In a golf ball having a core, envelope layer, intermediate layer and cover, the core has a specific hardness profile, the resin materials making up either or both of the envelope layer and the intermediate layer has a material hardness on the Shore D hardness scale of at least 65 and has a specific gravity of at least 1.05, and the Shore C hardness relationships among the core center, surface of the envelope-encased layer and surface of the intermediate layer-encased sphere satisfy the following conditions: surface hardness of envelope layer-encased sphere<surface hardness of intermediate layer-encased sphere,??(1) surface hardness of intermediate layer-encased sphere?center hardness of core?40.??(2) This ball achieves a good distance on shots with utility and iron clubs, is receptive to spin in the short game, and has a soft feel at impact on all shots, making it useful to amateur golfers.

Abstract: In a multi-piece solid golf ball having a core, envelope layer, intermediate layer and cover, the core is formed primarily of a base rubber, the core has a diameter of at least 30 mm, the envelope layer is formed as two layers—an inner layer and an outer layer, and the intermediate layer and the cover are each formed as single layers of a resin material. The core and the respective layer-encased spheres have surface hardnesses which satisfy specific relationships, the Shore C hardness value obtained by subtracting the core center hardness from the core surface hardness is 16 or more, and certain layers have respective thicknesses which satisfy specific conditions. This ball achieves a good distance on full shots both with a driver and with irons, is superior in the short game, and moreover has a good feel at impact and an excellent scuff resistance.

Abstract: In a golf ball having a core, an envelope layer, an intermediate layer and a cover, the core, the envelope layer-encased sphere obtained by encasing the core with the envelope layer, the intermediate layer-encased sphere obtained by encasing the envelope layer-encased sphere with the intermediate layer and the ball obtained by encasing the intermediate layer-encased sphere with the cover have respective deflections when compressed under a final load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf) which satisfy specific conditions. This ball achieves a good distance on shots with a utility club and with irons, is receptive to spin in the short game and has a soft feel at impact on all shots, making it useful to amateur golfers.

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 a base rubber and an ?,?-unsaturated metal carboxylate, 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 which accounts for at least 50 wt % of the resin composition, and a surface of the core outermost layer and the envelope layer adjoin each other through an intervening oxazoline group-containing substance. The golf ball has improved adhesion between the rubber-based core and the cover layer that directly encases the core and is formed of an ionomer resin or other ?,?-ethylenically unsaturated carboxylic acid copolymer-containing resin material.

Abstract: A golf ball for amateur golfers has both an excellent flight and a good, soft feel when hit by the average golfer whose head speed is not very high. The ball has a compressive deformation B when subjected to a final load of 50 kgf from an initial load of 5 kgf that is from 1.30 to 1.80 mm and a compressive deformation C when subjected to a final load of 90 kgf from an initial load of 5 kgf that is from 2.45 to 2.90 mm. The core of the ball has a hardness profile which satisfies the conditions (1) Cs?Cc?20 and (2) Cs?Cs?3?5.0, wherein Cs is the Shore C hardness at the core surface, Cs?3 is the Shore C hardness 3 mm inside the core and Cc is the Shore C hardness at the core center.

Abstract: A golf ball for amateur golfers is endowed with an excellent flight and a good feel at impact that is soft yet solid when hit by a golfer whose head speed is not very high. The ball, which includes a core and a cover, has a compressive deformation B when subjected to a final load of 30 kgf from an initial load state of 5 kgf that is from 0.72 to 0.97 mm and a compressive deformation C when subjected to a final load of 60 kgf from an initial load state of 5 kgf that is from 1.55 to 1.85 mm. In addition, the core has a hardness profile which satisfies specific conditions.

Abstract: To provide a golf ball that can prevent a decrease in carry distance of a driver shot when it rains and also, can exert excellent spinning performance upon an approach shot. The golf ball of the present invention includes a core, a cover that is provided on an outer side of the core and is provided with dimples, and an outermost layer that is formed on an outer side of the cover and made of a material having a contact angle of 90° or more. The golf ball has a dynamic friction coefficient of 0.52 or more. The material constituting the outermost layer comprises a urethane coating that contains a water repellent additive, and the water repellent additive includes a fluorinated surfactant, silicone-modified acrylate or hydrophobic silica.

Abstract: In a golf ball having a core, envelope layer, intermediate layer and cover, the core has a specific hardness profile, the resin materials making up either or both of the envelope layer and the intermediate layer contain a high-acid ionomer, and the Shore C hardness relationships among the core center, surface of the envelope-encased layer and surface of the intermediate layer-encased sphere satisfy the following conditions: surface hardness of envelope layer-encased sphere<surface hardness of intermediate layer-encased sphere,??(1) surface hardness of intermediate layer-encased sphere?center hardness of core?40.??(2) This ball achieves a good distance on shots with utility and iron clubs, is receptive to spin in the short game, and has a soft feel at impact on all shots, making it useful to amateur golfers.

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: An information processing apparatus that estimates a hit feeling of a golf ball, includes a characteristic amount obtainment unit configured to obtain a characteristic amount of a striking sound which an estimation target ball generates as a sound source upon the estimation target ball being struck and an estimation unit configured to estimate a hit feeling of the estimation target ball based on correlation information and the characteristic amount obtained by the characteristic amount obtainment unit. The correlation information indicates correlation, for a plurality of kinds of test balls, between a hit feeling which a testing golfer feels at the time of striking a test ball and a characteristic amount of a striking sound which the test ball generates as a sound source upon the test ball being struck.