Abstract: In a multi-piece solid golf ball having a core with a two-layer construction consisting of an inner layer and an outer layer and having also, over the core, a cover of two or more layers that includes an intermediate layer and an outermost layer, the core inner layer is formed primarily of a specific thermoplastic elastomer, the core outer layer is formed of a rubber material, and both the hardness relationship between the core inner layer and the core outer layer and the hardness relationship between the intermediate layer and the outermost layer are optimized. This golf ball allows even amateur golfers who do not have a high head speed to impart sufficient deformation to the ball and thus achieve an excellent flight performance and a comfortable feel at impact, and also has an excellent durability.

Abstract: In a multi-piece solid golf ball which has a core with a two-layer structure composed of an inner layer and an outer layer, and has over the core a cover of two or more layers that includes an intermediate layer and an outermost layer, the core inner layer is formed primarily of a specific thermoplastic elastomer, the core outer layer is formed of a rubber composition consisting primarily of a rubber material, and the hardness relationship between the core inner layer and the core outer layer and the hardness relationship between the intermediate layer and the outermost layer have been optimized. This golf ball has an excellent flight performance on full shots with a driver (W#1) and also has good controllability in the short game and a good durability.

Abstract: In a golf ball having a core and a cover of at least one layer, an outermost layer of the cover is formed to a specific thickness using a resin composition containing a light-harvesting fluorescent dye and a light-reflecting pigment. The golf ball is elegant and highly stylish, and moreover has an excellent visibility.

Abstract: A golf ball has a core, an envelope layer, an intermediate layer and a cover whose respective surface hardnesses have been set so as to satisfy certain specific relationships. In addition, the respective initial velocities measured for the core, a sphere composed of the core peripherally covered by the envelope layer (envelope layer-encased sphere), a sphere composed of the core peripherally covered by the envelope layer and the intermediate layer (intermediate layer-encased sphere), and the ball itself have been set so as to satisfy certain specific relationships. This golf ball is able to exhibit an excellent flight performance not only when struck by mid head-speed golfers, but even when struck by low head-speed golfers, in addition to which it also has a good feel at impact and an excellent durability to repeated impact.

Abstract: The invention provides a mold for injection-molding a golf ball, which mold has a cavity inner wall with a vertical diameter connecting both poles in a vertical direction thereof that is longer than a horizontal diameter connecting both poles in a horizontal direction thereof. A method of manufacturing golf balls using such a mold is also provided. The use of this mold eliminates molding problems that arise when molding the outermost cover layer of a golf ball, enabling the cover to be stably molded and also making it possible to easily and reliably obtain golf balls of high symmetry in which a cover of uniform thickness has been formed.

Abstract: In a multi-piece solid golf ball having a core, an envelope layer, an intermediate layer and a cover, the core is formed primarily of a thermoplastic elastomer, the envelope layer is formed of a rubber composition containing primarily a rubber material, the intermediate layer is formed of a resin composition containing primarily an ionomer, and the cover is formed of a resin composition containing primarily a urethane. The relationships among the specific gravities and the surface hardnesses of the respective layers are optimized. This golf ball enables an increased distance on full shots with a driver and improved controllability in the short game to be achieved, and also makes it possible to obtain a further reduction in the spin rate on full shots.

Abstract: A colored golf ball satisfies the following conditions: (i) a color difference ?E* between the inside layer and the ball of at least 30; (ii) the inside layer has a lightness L* value, expressed in the L*a*b* color system based on JIS 28729, of at least 82; (iii) the ball has a lightness L* value of at least 50; (iv) the lightness L* value of the ball?the lightness L* value of the inside layer; (v) the inside layer has a transparency which is up to 10% in terms of total transmittance and up to 1.0% in terms of parallel transmittance; (vi) the cover has a transparency which is at least 50% in terms of total transmittance and at least 1.0% in terms of parallel transmittance; and (vii) the inside layer has a haze (H), mentioned in JIS K7105 (1981), of at least 90.

Abstract: The invention provides, in a golf ball having a core, an intermediate layer and a cover, a golf ball which combines an intermediate layer formed of an ionomer resin material having a high degree of neutralization with a cover formed of a material that includes a first ionomer resin having a high unsaturated carboxylic acid content and a second ionomer resin having a low unsaturated carboxylic acid content. The golf ball is able to achieve a lower spin rate on full shots with a driver (W#1) without reducing the spin performance on approach shots in the short game, provides high levels of both flight performance and controllability, and also has a good feel at impact.

Abstract: A colored golf ball satisfies the following conditions: (i) a color difference ?E* between the inside layer and the ball of at least 30; (ii) the inside layer has a lightness L* value, expressed in the L*a*b* color system based on JIS 28729, of at least 82; (iii) the ball has a lightness L* value of at least 50; (iv) the lightness L* value of the ball?the lightness L* value of the inside layer; (v) the inside layer has a transparency which is up to 10% in terms of total transmittance and up to 1.0% in terms of parallel transmittance; (vi) the cover has a transparency which is at least 50% in terms of total transmittance and at least 1.0% in terms of parallel transmittance; and (vii) the inside layer has a haze (H), mentioned in JIS K7105 (1981), of at least 90.

Abstract: The invention provides a colored golf ball composed of a core, a cover having a plurality of dimples formed on an outside surface thereof, and an inside layer in contact with the cover. The ball satisfies the following conditions: (i) a color difference ?E* between the inside layer and the ball of at least 30; (ii) the inside layer has a lightness L* value, expressed in the L*a*b* color system based on JIS Z8729, of at least 82; (iii) the ball has a lightness L* value of at least 50; (iv) the lightness L* value of the ball?the lightness value of the inside layer; (v) the inside layer has a transparency which is up to 10% in terms of total transmittance and up to 1.0% in terms of parallel transmittance; (vi) the cover has a transparency which is at least 50% in terms of total transmittance and at least 1.0% in terms of parallel transmittance; and (vii) the inside layer has a haze (H), mentioned in JIS K7105 (1981), of at least 90.

Abstract: The invention provides a golf ball having a core, at least one intermediate layer encasing the core, and a cover. The intermediate layer is formed primarily of a specific ionomer resin composition that has been highly neutralized, and the cover is formed primarily of an ionomer resin composition containing a specific amount of a granular inorganic filler. The golf ball has an excellent durability to repeated impact and a good flight performance.

Abstract: A multi-piece solid golf ball has a core, an intermediate layer encasing the core, and a cover layer which encases the intermediate layer and has a plurality of dimples on an outer surface thereof. The intermediate layer is formed primarily of a material which includes specific amounts of a fatty acid and/or fatty acid derivative having a molecular weight of from 228 to 1500 and a basic inorganic metal compound capable of neutralizing un-neutralized acid groups per 100 parts by weight of a resin component composed primarily of a specific olefin-unsaturated carboxylic acid copolymer, and in which at least 82 mol % of acid groups in the above components are neutralized. The cover layer is formed of a thermoplastic resin composed primarily of an ionomer resin, and has a Shore D hardness of from 50 to 85. This invention makes it possible to achieve both an increased distance owing to a reduced spin rate, and also an improved durability.

Abstract: The invention provides a golf ball having numerous dimples on a surface thereof, wherein at least one dimple cross-sectional shape is a cycloid curve or a trochoid curve. By thus optimizing the cross-sectional shape of the dimples, the aerodynamic performance due to the dimple effect is enhanced, enabling the distance traveled by the ball to be increased.

Abstract: The invention provides a golf ball having a core, at least one intermediate layer encasing the core, and a cover. The intermediate layer is formed primarily of a specific ionomer resin composition that is highly neutralized. The cover is formed by injection molding a single resin blend composed primarily of a thermoplastic polyurethane and (g) a polyisocyanate compound in at least some portion of which all the isocyanate groups on the molecule are present in an unreacted state. The golf ball of the invention has a low spin rate on shots with a driver, enabling it to travel a good distance, and achieves a sufficient spin rate on shots with a short iron such as a wedge. The ball also has an excellent scuff resistance.

Abstract: The invention provides a golf ball having a core, at least one intermediate layer encasing the core, and a cover. The intermediate layer is formed primarily of a specific ionomer resin composition that has been highly neutralized, and the cover is formed primarily of an ionomer resin composition containing a specific amount of a granular inorganic filler. The golf ball has an excellent durability to repeated impact and a good flight performance.

Abstract: The invention provides a colored golf ball composed of a core, a cover having a plurality of dimples formed on an outside surface thereof, and an inside layer in contact with the cover. The ball satisfies the following conditions: (i) a color difference ?E* between the inside layer and the ball of at least 30; (ii) the inside layer has a lightness L* value, expressed in the L*a*b* color system based on JIS Z8729, of at least 82; (iii) the ball has a lightness L* value of at least 50; (iv) the lightness L* value of the ball?the lightness value of the inside layer; (v) the inside layer has a transparency which is up to 10% in terms of total transmittance and up to 1.0% in terms of parallel transmittance; (vi) the cover has a transparency which is at least 50% in terms of total transmittance and at least 1.0% in terms of parallel transmittance; and (vii) the inside layer has a haze (H), mentioned in JIS K7105 (1981), of at least 90.

Abstract: The invention provides a colored golf ball composed of a core, a cover having a plurality of dimples formed on an outside surface thereof, and an inside layer in contact with the cover. The ball satisfies the following conditions: (i) a color difference ?E* between the inside layer and the ball of at least 30; (ii) the inside layer has a lightness L* value, expressed in the L*a*b* color system based on JIS Z8729, of at least 82 and a chroma C, defined as (a*2+b*2)1/2, of at most 10; (iii) the ball has a lightness L* value of at least 50; (iv) the lightness L* value of the ball?the lightness L* value of the inside layer; (v) the inside layer has a transparency which is up to 10% in terms of total transmittance and up to 1.0% in terms of parallel transmittance; and (vi) the cover has a transparency which is at least 50% in terms of total transmittance and at least 1.0% in terms of parallel transmittance.

Abstract: The invention provides a golf ball composed of a core, a cover having a plurality of dimples on an outside surface thereof, and an intermediate layer disposed between the core and the cover. The core has a deflection, when compressed under a final load of 130 kgf from an initial load of 10 kgf, of at least 3.0 mm but not more than 5.0 mm. The intermediate layer is formed of a highly neutralized resin material, and has a Shore D hardness of at least 40 but not more than 60 and a thickness of at least 1.7 mm but not more than 4.0 mm. The number of dimples is at least 272 but not more than 348. The golf ball, through a combination of dimples which do not cause a loss of lift in the low-velocity, low-spin rate region of the ball trajectory and a low-spin construction, travels farther and is therefore beneficial for competitive use by both skilled and amateur golfers.

Abstract: The invention provides a golf ball composed of a core, a cover having a plurality of dimples on an outside surface thereof, and an intermediate layer disposed between the core and the cover. The intermediate layer is formed of a highly neutralized resin material, and has a Shore D hardness below 50 and a thickness of at least 1.7 mm but not more than 6.0 mm. The cover and the intermediate layer have a difference in Shore D hardness therebetween (cover Shore D hardness?intermediate layer Shore D hardness) of from 13 to 35. The cover and the intermediate layer have a combined thickness greater than 3 mm. The ball as a whole has a deflection, when compressed under a final load of 130 kgf from an initial load of 10 kgf, of at least about 2.0 mm but not more than about 4.0 mm.

Abstract: The invention provides a colored golf ball composed of a core, a cover having a plurality of dimples formed on an outside surface thereof, and an inside layer in contact with the cover. The ball satisfies the following conditions: (i) a color difference ?E* between the inside layer and the ball of at least 30; (ii) the inside layer has a lightness L* value, expressed in the L*a*b* color system based on JIS Z8729, of at least 82 and a chroma C, defined as (a*2+b*2)1/2, of at most 10; (iii) the ball has a lightness L* value of at least 50; (iv) the lightness L* value of the ball?the lightness L* value of the inside layer; (v) the inside layer has a transparency which is up to 10% in terms of total transmittance and up to 1.0% in terms of parallel transmittance; and (vi) the cover has a transparency which is at least 50% in terms of total transmittance and at least 1.0% in terms of parallel transmittance.