A multi-piece solid golf ball having a two-layer core with an inner core layer and an outer core layer and having a cover of one or more layer with numerous dimples on the surface is characterized in that the hardest cover layer has a specific material hardness and the ball has a specific value obtained by subtracting the surface hardness of the overall core from the surface hardness of the hardest cover layer, a specific deflection, and a specific value obtained by subtracting the initial velocity of the inner core layer from the initial velocity of the sphere consisting of the inner core layer encased by the outer core layer. This golf ball enables relatively low head speed golfers to achieve a good distance on full shots with drivers and iron clubs and also provides a soft, comfortable feel at impact.

A golf ball includes a core and a cover. The cover has a shore D hardness of not less than 50. The cover has a thickness of not less than 1.00 mm. The golf ball has a plurality of dimples 10 on a surface thereof. A standard deviation Su of areas of all the dimples 10 is not greater than 1.7 mm.sup.2. A standard deviation Pd of distances L between dimples of all neighboring dimple pairs is less than 0.500 mm. A dimple pattern of each hemisphere of a phantom sphere of the golf ball includes three units (T1, T2, T3) that are rotationally symmetrical to each other. A dimple pattern of the unit T1 includes two small units (T1a, T1b) that are mirror-symmetrical to each other.

In a golf ball having a two-layer core consisting of an inner core layer and an outer core layer, one or more intermediate layer, and a cover serving as an outermost layer, the inner core layer and outer core layer are each formed primarily of a base rubber, the inner core layer has a diameter of at least 21 mm, the intermediate layer and the cover are each formed primarily of a resin material, and the overall core has a specific hardness profile. The golf ball has a high initial velocity while holding down the spin rate on full shots with a driver or long iron, thus enabling a good distance to be achieved. The ball also has a high controllability in the short game.

An object of the present invention is to provide a golf ball traveling a great flight distance on driver shots and an excellent shot feeling. The present invention provides a golf ball comprising a spherical core, an intermediate layer covering the spherical core, and a cover covering the intermediate layer, wherein a material hardness (Hm) of a resin composition constituting the intermediate layer ranges from 65 to 80 in Shore D hardness, a material hardness (Hc) of a resin composition constituting the cover ranges from 57 to 72 in Shore D hardness, a hardness difference (HmHc) between the material hardness (Hm) and the material hardness (Hc) is more than 0, and the intermediate layer has a surface hardness satisfying a hardness difference (HmsCHmsD) between a hardness thereof shown in Shore C hardness (HmsC) and a hardness thereof shown in Shore D hardness (HmsD) of 27 or less.

A golf ball 2 includes a core 4, amid layer 6, a reinforcing layer 8, and a cover 10. The core 4 includes a center 12 and an envelope layer 14. The envelope layer 14 is formed by a rubber composition being crosslinked. The rubber composition includes a base rubber (a), a co-crosslinking agent (b), a crosslinking initiator (c), and an acid and/or a salt (d). The co-crosslinking agent (b) is: (b1) an ,-unsaturated carboxylic acid having 3 to 8 carbon atoms; or (b2) a metal salt of an ,-unsaturated carboxylic acid having 3 to 8 carbon atoms.

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.

An object of the present invention is to provide a golf ball excellent in flying performance, in particular, to provide a golf ball traveling a great flight distance. The present invention provides a golf ball having a spherical core and at least one cover layer covering the spherical core, wherein the spherical core is formed from a rubber composition containing (a) a base rubber, (b) an ,-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, (c) a crosslinking initiator, and (d1) an aromatic carboxylic acid or (d2) an aromatic carboxylic acid salt, provided that the rubber composition further contains (e) a metal compound in the case of containing only (b) the ,-unsaturated carboxylic acid having 3 to 8 carbon atoms as the co-crosslinking agent.

A golf ball 2 includes a center 8, a mid layer 10, a cover 6 and dimples 12. The cover 6 has a Shore D hardness of 30-50. The golf ball 2 has an amount of compressive deformation of 3.0-5.0 mm. The ball 2 meets a mathematical formula (I):

0.80((L1+L2)/2)0.95(I).

L1 represents a ratio of a lift coefficient CL1 relative to a drag coefficient CD1, the lift coefficient CL1 and the drag coefficient CD1 being measured under conditions of a Reynolds number of 1.29010.sup.5 and a spin rate of 2820 rpm. L2 represents a ratio of a lift coefficient CL2 relative to a drag coefficient CD2, the lift coefficient CL2 and the drag coefficient CD2 being measured under conditions of a Reynolds number of 1.77110.sup.5 and a spin rate of 2940 rpm.

An object of the present invention is to provide a golf ball resin composition by which durability can be improved without substantially reducing hardness and resilience, and a golf ball using the same. The present invention provides a golf ball resin composition containing (A) at least one member selected from the group consisting of an ionomer resin, a polyamide and a styrene-based elastomer, and (B) an acid modified polyolefin having a weight average molecular weight in a range from 5,000 to 80,000.

Multi-layered, golf balls having a core made of a foamed composition are provided. The core preferably has a foam inner core (center) and surrounding thermoset or thermoplastic outer core layer. The core also includes a structural insert such as, for example, a solid shell, perforated shell, a lattice or mesh, or a central hub with extending arms, and the like. The core layers have different hardness gradients and specific gravity values. The ball further includes a cover having at least one layer. By adjusting the respective specific gravity values of the core layers, the Moment of Inertia (MOI) of the ball can be increased or decreased. In one embodiment, the ball has generally good flight distance and low spin rate.