Multi-layered golf balls having a core, intermediate layer, and cover are provided. The ball includes a non-foamed inner core (center) made of a thermoplastic or thermoset composition such as polybutadiene rubber. An intermediate layer comprising a foamed composition, such as polyurethane foam, is disposed about the inner core. The foamed intermediate layer may have a specific gravity gradient within the layer, wherein the outer surface specific gravity is greater than the midpoint specific gravity. Ball constructions having two intermediate layers, wherein at least one layer is a foamed layer can be made. A cover having at least one layer is disposed about the intermediate layer.

In a golf ball having a core, an intermediate layer and a cover, the intermediate layer-encased sphere has a higher surface hardness than the ball. The core hardness profile in the ball is designed such that the core surface has a Shore C hardness value which is at least 28 higher than the Shore C hardness value at the core center, and the surface areas A to F calculated from hardness differences between positions located at specific distances in the core and differences between the specific distances satisfy a specific formula. This golf ball has an excellent flight performance when struck by skilled amateur golfers and professionals, and also has a good controllability on shots with an iron.

A golf ball for amateur golfers is endowed with both an excellent flight when hit by golfers whose head speed is not very high and a soft yet good feel at impact. The ball has a core, an envelope layer, an intermediate layer and a cover. The core is formed primarily of a base rubber and the intermediate layer is formed so as to be thicker than the envelope layer and the cover. The respective surface hardnesses of the core, envelope layer-encased sphere, intermediate layer-encased sphere and ball satisfy a specific relationship. The core hardness profile is designed such that the surface areas A to F calculated from hardness differences between positions located at specific distances in the core and differences between the specific distances satisfy a specific formula.

A golf ball including a spherical body, first regions, and second regions. The spherical body includes a core layer and a cover layer made from a synthetic resin covering the core layer. Dimples are formed in a surface of the cover layer. First regions that are electrically conductive are formed on a surface of the spherical body. The first regions are formed on a spherical surface having a center of the spherical body as a center. The first regions are positioned at six vertices of an imaginary regular hexahedron such that the vertices are positioned on the surface of the spherical body and, thus, six of the first regions are formed. The second regions are formed in areas of the surface other than where the first regions are formed. The second regions have a radio wave reflectance lower than that of the first regions.

Multi-piece golf balls having a multi-layered solid core and multi-layered cover are provided.

A golf ball includes a core, a mantle and a cover layer. The core includes polybutadiene and has a diameter of less than 1.45 inches. The core has a deflection of at least 0.220 inches under an applied static load of 200 pounds. The mantle includes a copolymer of ethylene and carboxylic acid. The carboxylic acid contains a plurality of acid groups wherein 40 to 100 percent of the acid groups of the carboxylic acid are neutralized with a metal ion. The cover layer includes a polyurethane material and has a Shore C hardness of greater than 80.

In a golf ball for professional golfers and skilled amateurs which has a single-layer core, a cover and at least one intermediate layer therebetween, the intermediate layer has a specific gravity of at least 1.05, the sphere the sphere obtained by encasing the core with the intermediate layer (intermediate layer-encased sphere) and the ball have a surface hardness relationship which satisfies the condition:

(surface hardness of intermediate layer-encased sphere)>(surface hardness of ball).

The core has a diameter of from 35.5 to 39.5 mm and a distinctive hardness profile that satisfies specific conditions. The ball is endowed with both an excellent flight performance and excellent durability to repeated impact.

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 has 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 having a dynamic friction coefficient of 0.52 or more. The cover may be formed of thermoplastic polyurethane having hardness of 55 or more in terms of Shore D Hardness. The outermost layer may be formed of a urethane coating containing a water repellent additive, as a main component.

An object of the present invention is to provide a golf ball that can strike a good balance in approach performance under a rough condition and a wet condition while maintaining a flight distance on driver shots. The present invention provides a golf ball comprising a golf ball body and a paint film formed on a surface of the golf ball body, wherein the golf ball body has a spherical core, an intermediate layer covering the spherical core, and a cover covering the intermediate layer, and the paint film has a multi-layered construction composed of two or more layers, wherein a 10% elastic modulus (Pi10) of an innermost layer of the paint film is greater than a 10% elastic modulus (Po10) of an outermost layer of the paint film and a 10% elastic modulus (C10) of a material constituting the cover, and a thickness (Ti) of the innermost layer of the paint film is greater than a thickness (To) of the outermost layer of the paint film, a 10% elastic modulus (M10) of a material constituting the intermediate layer is greater than the 10% elastic modulus (C10) of the material constituting the cover, and a difference (Po10C10) between the 10% elastic modulus (Po10) of the outermost layer of the paint film and the 10% elastic modulus (C10) of the material constituting the cover is 4.0 kgf/cm.sup.2 or more and 50 kgf/cm.sup.2 or less, and a Shore D hardness (Hc) of the material constituting the cover is 40 or less.

An object of the present invention is to provide a golf ball having good spin performance on approach shots and good shot feeling as well as excellent stain resistance by precisely controlling physical properties of a paint film actually formed on a surface of a golf ball body. The present invention provides a golf ball comprising a golf ball body and a paint film formed on a surface of the golf ball body, wherein the paint film is such that a linear approximation curve obtained by a least square method has a slope in an absolute value ranging from 0.0001 to 0.0020 when a loss tangent tan thereof measured by a nanoindentation method is plotted as a vertical axis against a measuring frequency (Hz) as a horizontal axis, and that an elastic modulus thereof measured by a nanoindentation method ranges from 0.040 GPa to 0.600 GPa.