The present invention provides a method for arranging dimples on a golf ball surface in which the dimples are arranged in a pattern derived from at least one irregular domain generated from a regular or non-regular polyhedron. The method includes choosing control points of a polyhedron, generating an irregular domain based on those control points, packing the irregular domain with dimples, and tessellating the irregular domain to cover the surface of the golf ball. The control points include the center of a polyhedral face, a vertex of the polyhedron, a midpoint or other point on an edge of the polyhedron and others. The method ensures that the symmetry of the underlying polyhedron is preserved while minimizing or eliminating great circles due to parting lines.

A golf ball having a core and a cover that is formed of a resin composition which includes (A) a polyurethane or a polyurea and (B) a styrenic resin material, when dropped from a height of 3 m and made to collide with a metal plate, has velocities 200 ms before and 200 ms after contact that satisfy the condition: (incident velocity)(rebound velocity)0.80 m/s. The ball has a good controllability on approach shots without a loss in the distance achieved on shots with a driver, and thus is particularly useful to professional golfers and skilled amateurs.

The golf ball 1 includes a surface having multiple dimples thereon. When a lift coefficient measured under conditions with a Reynolds number of 80000 and a spin rate of 2000 rpm is CL1, and when a lift coefficient measured under conditions with a Reynolds number of 70000 and a spin rate of 1900 rpm is CL2, CL1 and CL2 satisfy 0.990CL2/CL1.

The present invention is directed to a mold for forming the cover of a golf ball having a non-planar parting line on its spherical surface.

Method of making golf ball comprising aligning thermoformed depressions with dimpled mold cups and applying sufficient heat and suction to the thermoformed depressions without exposing any preselected subassembly to the heat and suction to soften the polymeric material of each thermoformed depression and draw air outward from a volume located between an inner surface of the dimpled mold cup and an outer surface of the thermoformed depression to form a thermoformed pre-form half-shell having an outer surface with the size, shape and contour of the inner surface of the dimpled mold cup(s) and an inner surface with the size, shape and contour of the outer surface of a preselected subassembly. Afterwards, a preselected subassembly is loaded between a pair of thermoformed pre-form half-shells and molded under sufficient short-term heat and suction to form the golf ball. The thickness of each thermoformed depression and thermoformed pre-form half-shell may be tapered.

Golf balls including at least one modified dimple group are disclosed. The modified dimple group comprises one or more modified dimples forming an axially symmetric pattern about a Correction Area Centroid located on an axis of symmetry at a latitude greater than 0, where 0 represents the hemispherical pole and 90 represents the equator. The modified dimples can be altered, for example, by changing dimple coverage, dimple diameter, dimple depth, dimple edge angle, dimple volume, dimple cross-sectional shape, and/or dimple plan shape. Optionally, the dimples have a catenary cross-sectional shape and the modified dimples are altered by changing the shape factor and/or chord depth. Such modifications preferably produce a golf ball that flies more consistently regardless of orientation when struck than a corresponding golf ball without such modifications.

The present invention provides golf balls having a pattern of stellated polygon shaped dimples and grooves with pre-selected and coordinated color appearances on the outer surface of the ball to produce a unique and desirable overall golf ball color appearance.

In a golf ball having a core of at least one layer and a cover of one or more layer encasing the core, at least one layer of the cover is formed of a resin composition that includes (I) a polyurethane or a polyurea and (II) an aromatic vinyl elastomer which together satisfy certain specific conditions. The golf ball has an excellent controllability on approach shots and is also able to maintain a good scuff resistance.

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. An average depth Fav of the dimples 12 and an average height Hav of the minute projections satisfy the following mathematical formula (1).
Hav/Fav0.050(1)
A ratio M (%) of a sum of areas of all the dimples 12 relative to a surface area of a phantom sphere of the golf ball and an average value Pav (m) of pitches P each between a minute projection 18 and another minute projection 18 adjacent to this minute projection 18 satisfy the following mathematical formula (2).
M/Pav>0.3(2)