Golf balls comprising a multi-layer core and a cover are disclosed. The multi-layer core comprises at least one intermediate core layer formed from a metallic, composite, or inorganic/organic hybrid composition.

Golf balls having multi-layered covers, wherein at least one of the cover layers is substantially transparent, are provided. The cover includes an inner cover layer made of an ionomer composition; an intermediate cover layer made of an aromatic polyurethane composition; and outer cover layer made of an aliphatic polyurethane composition, wherein the total thickness of the multi-layered cover is no greater than 0.110 inches. In one version, the outer cover layer is substantially transparent and the underlying intermediate cover layer is colored. In another version, both the outer and intermediate cover layers are substantially transparent. Light-reflective fillers such as pearlescent pigments, glitter, and metallics may be added to the cover layers. The resulting ball has pleasing decorative effects.

In a golf ball having a rubber core and an intermediate layer and outermost layer which encase the core, the intermediate layer is formed of a thermoplastic resin composition which has a flexural rigidity of 400 to 500 MPa and a melt flow rate of 15 g/10 min or less and includes 50 to 100 wt % of a magnesium salt of an ethylenically unsaturated carboxylic acid copolymer, the outermost layer is formed of a polyurethane resin composition having a Shore D material hardness of 55 or less, and the golf ball has a deflection within a given range. Compared with conventional golf balls containing the high-rigidity ionomer resins hitherto used as intermediate layer materials, this ball suppresses the spin rate on shots with a driver and long and middle irons, enabling an increased distance to be obtained, and also has a high durability to repeated impact.

A thermoplastic multi-layer golf ball has a core center including a first thermoplastic material, a core layer including a second thermoplastic material, and a cover including a third thermoplastic material. The core center has a diameter of 21-29 mm and a surface Shore D hardness H1 of less than about 50. The core layer is at least about 5 mm thick with an outer surface Shore D hardness H2 of more than about 50. The cover has an outer surface Shore D hardness H3 of more than about 60. H3 is up to about 20 Shore D units higher than H2, and H2 is up to about 10 Shore D units higher than H1. The core layer has a specific gravity that is at least 0.1 g/cm.sup.3 greater than the specific gravity of the core center.

An object of the present invention is to provide a golf ball having excellent shot feeling and flight distance. The present invention provides a golf ball comprising a spherical core, a first resin layer and a second resin layer, wherein the first resin layer is formed from a first resin composition containing (A) a polyamide resin, (B) a copolymer and/or a metal ion-neutralized product thereof, and (C) a thermoplastic elastomer, and having a ratio (flexural elastic modulus/slab hardness) of a flexural elastic modulus (MPa) to a slab hardness (Shore D hardness) in a range from 3 to 5; and the second resin layer is formed from a second resin composition containing (D) a polyamide resin, and (E) a copolymer and/or a metal ion-neutralized product thereof.

Multi-layered golf balls having at least one layer made of a foamed silicone composition are provided. Multi-layered golf balls having at least one layer made of non-foamed silicone elastomer composition also are provided. For example, three-piece, four-piece, and five-piece golf balls containing different core and cover structures can be made. The foamed silicones have good thermal stability and durability without sacrificing resiliency. The non-foamed silicone elastomers have high elongation, tensile strength, chemical/fluid-resistance, and weatherability properties. These compositions can be used to form any layer, for example, core, intermediate, or cover, in the golf ball.

Golf balls having covers made of thermoplastic polyurethane compositions are provided. Multi-piece golf balls can be made. Polyurethane primer coatings and polyurethane top-coatings are applied to the thermoplastic polyurethane cover. Isocyanate-rich and polyol-rich polyurethane coatings can be applied. In one embodiment, multi-functional imine and amine compounds can be used to treat the golf ball. 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. Heat is used to cure the coatings. The coating methods have many benefits and the finished balls have good physical properties.

Methods for coatings for golf balls, particularly golf balls having thermoplastic polyurethane covers, and the resulting finished balls are provided. The coating is preferably a topcoat comprising a polyurethane composition containing optical brighteners. The topcoat composition preferably comprises a low concentration of optical brighteners. For example, the concentration of optical brightener can be in the range of 0.01 to about 0.20 weight %. The optical brighteners provide the desired brightness to the golf ball without sacrificing color stability. Multi-piece golf balls having inner cores, outer cores, inner covers, and intermediate layers can be made. The finished ball with the topcoat has many advantageous physical and playing performance properties.

A rubber composition for golf balls includes (A) a base rubber, (B) an acrylate ester or methacrylate ester containing an isocyanate group or a blocked isocyanate group, (C) diacrylic acid, dimethacrylic acid or a metal salt thereof, and (D) an organic peroxide. In a golf ball having a core formed of the rubber composition and a cover of one or more layers which encases the core, the rubber composition exhibits a spin rate-lowering effect on shots and can thus improve the flight performance of the ball.

In a multi-piece solid golf ball having a core, an envelope layer, an intermediate layer and a cover, the core, an intermediate layer-encased sphere and the ball have surface hardnesses which satisfy a specific relationship, and the envelope layer, the intermediate layer and the cover have thicknesses which satisfy a specific relationship. Also, the core has a hardness profile in which the hardnesses at the core surface, core center, a position 5 mm from the core center, and a position midway between the surface and center of the core satisfy specific relationships. This golf ball, when used by mid- and high-level amateurs, enables the golfer to maintain an adequate distance on shots with a driver and achieve a good distance on iron shots, has a good spin performance on approach shots and has a good feel on impact. In addition, the ball has an excellent scuff resistance when struck with a grooved wedge.