A method for producing a golf ball of the present invention includes the steps of: forming a first coating film on a surface of a covering having a plurality of dimples; and forming a second coating film on a surface of the first coating film. The second coating film is formed of a second coating material composition containing a polyurethane coating material and a solvent having a boiling point of 80° C. or less. An elastic recovery rate of the second coating film is 50% or more. In the golf ball of the present invention obtained by the method, an edge ratio which is a ratio of a film thickness of the second coating film in an edge portion of the dimple to a film thickness of the second coating film in a central portion of the dimple is 50% or more.

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.

Golf balls having outer surfaces with improved dimple patterns are provided. At least a portion of the dimples are spherical, and the spherical dimples have at least two different dimple diameters. Each spherical dimple has a radius of curvature that is substantially equal to the radius of curvature of every other spherical dimple on the outer surface of the ball. In another embodiment, the spherical dimples have at least three different dimple diameters. The spherical dimples having different dimple diameters also can have different edge angles, dimple depths, and/or dimple volumes. In one preferred embodiment, the maximum difference in radius of curvature between any two spherical dimples is less than or equal to 0.015 inches.

Golf balls having a dimple pattern arranged in an icosahedral layout are disclosed. The dimple pattern has 20 substantially identical dimple sections, where each dimple section is defined by a spherical triangle. The dimples in each of the 20 dimple sections have at least three different dimple diameters including a minimum dimple diameter, a maximum dimple diameter, and at least one additional dimple diameter. The resulting dimple pattern has a surface coverage of about 70 percent or less. The reduced surface coverage helps to reduce the flight of the golf balls.

Golf balls having dimple patterns arranged in dipyramid layouts are disclosed. The patterns may be arranged in triangular dipyramid, quadrilateral dipyramid, pentagonal dipyramid, or hexagonal dipyramid layouts. The dipyramid patterns have six, eight, ten, or twelve substantially identical dimple sections, where each dimple section is defined by a spherical triangle. The dimples in each of the identical dimple sections have at least two different dimple diameters including a minimum dimple diameter and a maximum dimple diameter. The resulting dimple patterns have a surface coverage of about 70 percent or less. The reduced surface coverage helps to reduce the flight of the golf balls.

A method for producing a golf ball of the present invention includes the steps of: forming a first coating film on a surface of a covering having a plurality of dimples; and forming a second coating film on a surface of the first coating film. The second coating film is formed of a second coating material composition containing a polyurethane coating material and a solvent having a boiling point of 80° C. or less. An elastic recovery rate of the second coating film is 50% or more. In the golf ball of the present invention obtained by the method, an edge ratio which is a ratio of a film thickness of the second coating film in an edge portion of the dimple to a film thickness of the second coating film in a central portion of the dimple is 50% or more.

A golf ball can have a relatively large number of dimples on a surface thereof. A trajectory of the golf ball calculated under conditions of an initial speed of 260 ft/s, a launch angle of 15.0 degrees, and an initial backspin rate of 3000 rpm can satisfy the following mathematical formula:

Amin≥−5.0*Vave−38.98,

wherein A min represents a minimum value (degree) of a vector angle A in the trajectory, and Vave represents an average volume (mm.sup.3) of the dimples. The vector angle A can be calculated by the following mathematical formula:

A=ATAN(Vy/Vx),

wherein Vx represents a horizontal component of a speed of the golf ball, and Vy represents a vertical component of the speed of the golf ball.

A golf ball can have a large number of dimples on a surface thereof. A trajectory of the golf ball can be calculated under conditions of an initial speed of 260 ft/s, a launch angle of 15.0 degrees, and an initial backspin rate of 3000 rpm satisfying the following mathematical formula,

[00001]$\text{Amax}\ge \text{4}\text{.0}\text{*}\text{Vave + 13}\text{.10,}$

wherein Amax represents a maximum value (degree) of a vector angle A in the trajectory, and Vave represents an average volume (mm.sup.3) of the dimples. The vector angle A can be calculated by the mathematical formula

[00002]$\text{A}\text{=}\text{ATAN}\left(\text{Vy}/\text{Vx}\right),$

wherein Vx represents a horizontal component of a speed of the golf ball, and Vy represents a vertical component of the speed of the golf ball.

Golf balls according to the present invention achieve flight symmetry and overall satisfactory flight performance due to a dimple surface volume ratio that is equivalent between opposing hemispheres despite the use of different dimple geometries, different dimple arrangements, and/or different dimple counts on the opposing hemispheres.

A golf ball dimple pattern based on a square dipyramid, i.e., two square pyramids connected base-to-base, is disclosed. The dimples are arranged within four substantially identical triangular sections on each of two substantially identical hemispheres of the ball.