Provided are a golf ball and a resin composition for a cover or topcoat thereof which can suppress the yellowing of the golf ball caused by ultraviolet rays even if a naturally derived substance is used as an ultraviolet absorber, and they are environmentally and human friendly. A resin composition for a cover or topcoat of a golf ball of the present invention contains: a resin for a cover or topcoat; and a plant-derived extract which absorbs ultraviolet rays. The resin composition has a color difference ΔE of 10.0 or less in a Lab color system between before and after a color tone change test, the color tone change test being carried out by irradiating a film formed from the resin composition with a xenon lamp. In the golf ball of the present invention, the cover or the topcoat is formed by using the resin composition.

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.

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 is provided with 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 has a dynamic friction coefficient of 0.52 or more. The material constituting the outermost layer comprises a urethane coating that contains a water repellent additive, and the water repellent additive includes a fluorinated surfactant, silicone-modified acrylate or hydrophobic silica. The urethane coating comprises a polyisocyanate as a curing agent, and the polyisocyanate includes both an adduct form and an isocyanurate form of hexamethylene diisocyanate, and a mixing ratio (isocyanurate form/adduct form) of the isocyanurate and adduct forms of the hexamethylene diisocyanate, expressed as a mass ratio, is from 95/5 to 40/60.

An apparatus and method of indicating the ball center of gravity position. The method of indicating the ball center of gravity position includes the following step of: moving the ball to a rotating member of a rotating device; driving the rotating member to rotate the ball along a axis of rotation of the rotating device, and adjust the center of gravity of the ball corresponding to the position of the rotating device; moving the ball onto a first carrier of a first transport device; and marking an identification mark on a predetermined area of the ball.

A method for manufacturing a golf ball having a non-uniform dot pattern is provided. Firstly, a semi-finished product of a golf ball is provided, which includes a ball body and a base layer covering an outer surface of the ball body. After that, the semi-finished product of the golf ball is rotated at a predetermined rotation speed, and a color paint is applied to the semi-finished product of the golf ball in a spraying manner from each of an upper position and a lower position.

An apparatus for manufacturing golf balls each having an exterior pattern includes a conveying device and a spraying device. The spraying device is disposed at one side of a first processing area. The conveying device is configured to convey a ball-shaped body into the first processing area along a predetermined path, and to rotate the ball-shaped body at a predetermined speed. The spraying device includes a first sprayer and a second sprayer. The first sprayer and the second sprayer are configured to apply a color paint to the ball-shaped body from each of an upper position and a lower position.

A golf ball alignment device includes a golf ball having an exterior surface. Indicia is disposed on the exterior surface of the golf ball. The indicia include first and second line segments extending along a portion of the golf ball at a spaced interval. The spaced interval is narrower at a first end of each line segment than at a second end of each line segment such that the line segments converge from the second end of the line segments to the first end of the line segments. The indicia provide an alignment reference on the golf ball for a user to align the line segments with at least one of an intended direction of travel of the golf ball and a club head used to strike the ball in the intended direction of travel.

Golf balls including one or more layers having at least one radar detectable mark disposed on the surface thereof are provided.

A golf ball 2 includes a core 4 and a cover 6 positioned outside the core 4. The cover 6 is formed in a mold having support pins by injection molding. A ratio (V/S) of a volume V (mm.sup.3) of the cover 6 to an amount of compressive deformation S (mm) of the core 4 is not less than 1000 and not greater than 1900. The cover 6 has a shore D hardness of not greater than 62. The golf ball 2 has a plurality of dimples 8 on a surface thereof. A total volume W of these dimples is not less than 490 mm.sup.3 and not greater than 620 mm.sup.3. A ratio (α/P) of a latitude α (degree) of each support pin to a total cross-sectional area P (mm.sup.2) of the support pins is not less than 0.35 and not greater than 0.60.

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 layers—an 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 hardness that satisfy a specific relationship. The inner envelope layer or outer envelope layer is formed primarily of one or more elastomer, and further the core has a particular hardness profile. 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.