In a multi-piece solid golf ball having a core formed of a rubber composition, an intermediate layer formed of a polyurethane material and a cover, the ball satisfies the following condition: surface hardness of ballsurface hardness of intermediate layer-encased sphere. When the ball is struck with a driver at a head speed of 40 m/s, the sum of the time t1 required from contact initiation between the driver and ball for deformation of the ball to reach a maximum value and the time t2 required from the state of maximum ball deformation for the ball and driver clubface to separate is at least 705 microseconds. This ball has an excellent flight performance when hit by low or moderate head-speed golfers, is receptive to spin on approach shots and has a good, soft feel at impact.

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 may comprise 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 %. 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 golf ball has a plurality of dimples 12 and a land 14 on a surface thereof. The golf ball further has a large number of minute projections 18 formed on surfaces of the dimples 12 and the land 14. The surface of the golf ball has an arithmetic average height Sa of not less than 0.5 m and not greater than 30 m. An average value Hav of heights H of the minute projections 18 is not less than 0.5 m and not greater than 50 m. A ratio Pp of a sum of areas of all the minute projections 18 to a surface area of a phantom sphere of the golf ball is not less than 7%. An average value Dav of diameters D of the minute projections 18 is not less than 5 m and not greater than 50 m.

In a multi-piece solid golf ball having a core, an envelope layer, an intermediate layer and a cover, the envelope layer is formed into two layersan inner envelope layer and an outer envelope layer. The inner envelope layer-encased sphere, outer envelope layer-encased sphere, intermediate layer-encased sphere and ball have respective surface hardnesses that satisfy a specific relationship. The inner envelope layer or outer envelope layer is formed primarily of one or more thermoplastic elastomer selected from the group consisting of polyester elastomers, polyamide elastomers, polyurethane elastomers, olefin elastomers and styrene elastomers. This ball has an excellent flight when struck by golfers whose head speeds are not that fast and has a good, soft feel at impact, thus making it highly suitable for amateur golfers.

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 base rubber and has a diameter set in a specific range, the envelope layer, intermediate layer and cover are each formed of resin materials, and the envelope layer is formed into two layersan inner layer and an outer layer. The center and surface hardnesses of the core, the surface hardness of the inner envelope layer-encased sphere, the surface hardness of the outer envelope layer-encased sphere, the surface hardness of the intermediate layer-encased sphere and the surface hardness of the ball together satisfy a specific relationship. This ball achieves a satisfactory distance on full shots both with a driver and with irons, in addition to which it is superior in the short game and has a good feel at impact and an excellent scuff resistance.

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. Different coating methods can be used. Isocyanate-rich and polyol-rich polyurethane coatings can be applied. In one embodiment, the golf ball can be treated with a multi-functional isocyanate prior to applying the coatings. The polyurethane 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.

In a multi-piece solid golf ball having a core formed of a rubber composition, an intermediate layer formed of a polyurethane material and a cover, the ball satisfies the following condition: surface hardness of ballsurface hardness of intermediate layer-encased sphere. When the ball is struck with a driver at a head speed of 40 m/s, the sum of the time t1 required from contact initiation between the driver and ball for deformation of the ball to reach a maximum value and the time t2 required from the state of maximum ball deformation for the ball and driver clubface to separate is at least 685 microseconds, and the ratio t2/t1 is at least 1.35, and the core has a specific hardness profile. This ball has an excellent flight performance when hit by low or moderate head-speed golfers, is receptive to spin on approach shots and has a good, soft feel at impact.

A matte colored golf ball which is free of luster and gloss has a good appearance in which injection marks that form during injection molding of a cover layerbe it an intermediate layer or an outermost layerare difficult to see and scuffing on the cover surface is inconspicuous. The golf ball includes a core, an outermost layer, an intermediate layer therebetween, and a coat formed on the surface of the outermost layer. The intermediate layer is formed of a resin composition containing a thermoplastic resin and a colorant consisting of a fluorescent dye or a fluorescent pigment and has a specific visible light transmittance, the outermost layer is molded of a transparent or translucent resin composition that is free of fluorescent dye, and the coat is formed of a urethane-based coating composition containing delustering particles.

A golf ball having a cover with a plurality of dimples on the surface thereof is provided with a coat of mutually differing properties on dimple areas of the surface and on land areas between the dimples. The dimple areas are formed with a coat having a low coefficient of friction, do not affect the spin performance when the ball is struck and are not prone to staining. The land areas are formed with a coat having a high coefficient of friction, enabling a lower spin rate to be achieved and thus increasing the distance traveled by the ball, particularly when struck with a middle iron, and also help impart a high spin rate and a good controllability on approach shots.

A golf ball has a plurality of dimples 12 and a land 14 on a surface thereof. The golf ball further has a large number of minute projections 18 formed on surfaces of the dimples 12 and the land 14. The surface of the golf ball has an arithmetic average height Sa of not less than 0.5 m and not greater than 30 m. An average value Hav of heights H of the minute projections 18 is not less than 0.5 m and not greater than 50 m. A ratio Pp of a sum of areas of all the minute projections 18 to a surface area of a phantom sphere of the golf ball is not less than 7%. An average value Dav of diameters D of the minute projections 18 is not less than 5 m and not greater than 50 m.