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.

In a golf ball having a core, an envelope layer, an intermediate layer and a cover, the difference between the center hardness and the surface hardness of the core is set in a specific range, the intermediate layer is formed of a resin material that includes a high-acid ionomer, the Shore C hardness relationships among the core center and the surfaces of the envelope-encased layer and the intermediate layer-encased sphere satisfy specific conditions; and the ball has a deflection when compressed under a given load which is at least 2.7 mm. This ball achieves a good distance on shots with a driver, utility club or iron, is receptive to spin in the short game, and has a soft feel at impact on all shots, making it useful to amateur golfers.

A golf ball a core, one or more intermediate layers, and one or more cover layers. The core may comprise an inner portion and an outer portion. One or more layers of the golf ball may be formed by the application of ultrasonic welding on two half shells to form. One or more of the layers may be formed by a number of different chemical compositions, and may have varying thicknesses, hardnesses, coefficients of restitution, and PGA compression. The golf ball itself may have varying coefficient of restitution and PGA compression, depending on the layers.

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 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 epoxy compound. Mixtures of multi-functional amines and imines, and multi-functional isocyanates, and epoxy curing agents; and solvent, can be applied to the outer cover. The resulting coating may contain polyurethanes, polyureas, and hybrids, copolymers, and blends thereof. 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 have good physical properties.

A golf ball with improved durability is disclosed herein. The golf ball has a mantle layer comprising a blend of ionomers and methyl methacrylate, butadiene, styrene (MBS) with a weight percentage of MBS ranging from 5 to 15 weight percent of the mantle layer.

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 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 α,β-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.

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:

(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.