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  (3)

cover thickness<envelope layer thickness  (4)

envelope layer thickness≥0.8 mm.  (5)

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.

Golf balls having a single or dual-layered solid core are provided. In one embodiment, the golf ball has dimensions and properties that do not conform to the rules of the United States Golf Association (USGA). For example, the ball weight; ball size; ball spherical symmetry; ball initial velocity; and/or ball overall distance may fall outside of the USGA standards. The dual-layered core can have an inner core comprising a thermoplastic composition and surrounding outer core comprising a thermoset composition. In another embodiment, the dual-layered core has an inner core comprising a thermoplastic composition and outer core comprising a thermoset composition. The thermoplastic composition preferably comprises an ethylene acid copolymer ionomer and plasticizer. The thermoset composition preferably comprises polybutadiene rubber. The ball further includes a cover of at least one layer.

Golf balls having covers made of thermoplastic polyurethane compositions are provided. Multi-piece golf balls can be made. In one embodiment, the outer cover layer is formed from a composition comprising a thermoplastic polyurethane and polydimethylsiloxane compound. Functionalized polydimethylsiloxane compounds also can be used to treat thermoplastic polyurethane golf ball covers. The cover composition and surface coatings can further include catalysts, ultraviolet (UV)-light stabilizers, and other additives. The coating methods have many benefits and the finished balls with thermoplastic polyurethane covers have good physical properties.

Golf balls having three-dimensional shaped fret areas and methods of making the same are disclosed. The three-dimensional shaped fret areas have at least three edges that meet at an apex point or an apex surface. The three-dimensional shaped fret areas may have a three-dimensional irregular pyramid shape or a three-dimensional truncated irregular pyramid shape. The three-dimensional shaped fret areas create golf balls having increased traction upon impact with the playing surface.

An object of the present invention is to provide a golf ball travelling a great flight distance on driver shots, having enhanced controllability on approach shots under a wet condition, and being excellent in stain resistance and shot feeling. The present invention provides a golf ball comprising a golf ball body having a cover, and a paint film covering the golf ball body, wherein a 10% elastic modulus of the paint film is 75 kgf/cm.sup.2 or less, a storage modulus (E′.sub.150) at 150° C. of the paint film obtained by measuring dynamic viscoelasticity of the paint film is 1.0×10.sup.7 Pa or more, an indentation depth of the paint film measured with a nanoindenter in a state that the paint film is formed on the surface of the golf ball body is 1250 nm or more, and a material hardness of the cover is 50 or more in Shore D hardness.

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.  (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.

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.

This ball enables mid-level and skilled amateur golfers to achieve superior distances on driver and iron shots, and moreover has a soft yet good feel.

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.

Golf balls having covers made of thermoplastic polyurethane compositions are provided. Multi-piece golf balls can be made. In one embodiment, the outer cover layer is formed from a composition comprising a thermoplastic polyurethane and polydimethylsiloxane compound. Functionalized polydimethylsiloxane compounds also can be used to treat thermoplastic polyurethane golf ball covers. The cover composition and surface coatings can further include catalysts, ultraviolet (UV)—light stabilizers, and other additives. The coating methods have many benefits and the finished balls with thermoplastic polyurethane covers have good physical properties.

A golf ball 2 includes a main body 4 and a paint layer 6 positioned outside the main body 4. The main body 4 includes a spherical core 8, a mid layer 10 positioned outside the core 8, and a cover 12 positioned outside the mid layer 10. An indentation depth, measured when the paint layer 6 in a cross-section along a plane passing through a central point of the golf ball 2 is pressed by a force of 30 mgf in a direction perpendicular to the cross-section, is not less than 300 nm and not greater than 3000 nm. The paint layer 6 preferably has a thickness of not less than 5 μm and not greater than 50 μm.