An object of the present invention is to provide a golf ball having a decreased spin rate on driver shots. The present invention provides a golf ball comprising 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) two or more α,β-unsaturated carboxylic acids having 3 to 14 carbon atoms and having no substituent group at a carbon atom bonding to the carboxy group, and/or a metal salt thereof, and (c) a crosslinking initiator.

A golf ball has a core, an inner cover, an outer cover, and dimples. The golf ball satisfies the following mathematical formulas.
Sa=4500+10(A−0.5B−2Cs)≥4000
0.04Sa+160−20≤D≤0.04Sa+160+20 A: a compression (Atti) of the golfball B: a hardness difference (Shore C) between a surface and a center of the core Cs: (Hi×Ti+2Ho×To)/(Ti+2To) D: a total volume (mm.sup.3) of the dimples Hi: a hardness (Shore D) of the inner cover Ho: a hardness (Shore D) of the outer cover Ti: a thickness (mm) of the inner cover To: a thickness (mm) of the outer cover

An object of the present invention is to provide a golf ball having a decreased spin rate on driver shots. The present invention provides a golf ball comprising 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) a compound represented by the formula (1) as a co-crosslinking agent, and (c) a crosslinking initiator,
(R.sup.1COO)M(OCOR.sup.2)m  (1) in the formula (1), M represents a metal atom, m represents 1 or 2, R.sup.1 and R.sup.2 are different from each other, represent an alkenyl group having 2 to 30 carbon atoms or an alkynyl group having 2 to 30 carbon atoms and have a carbon-carbon double bond or a carbon-carbon triple bond at an α-position carbon atom bonding to the carbonyl group, and when m is 2, two of R.sup.2 may be identical to or different from each other.

In a golf ball having a core, a cover and at least one intermediate layer between the core and the cover, the core is made of a material molded under heat from a rubber composition that includes (a) a base rubber, (b) a co-crosslinking agent which is an α,β-unsaturated carboxylic acid and/or a metal salt thereof, (c) an organic peroxide, (d) water, and (e) an antioxidant which is a benzimidazole of a specific formula and/or a metal salt thereof. The core and ball have compressive deformations within specific respective ranges when subjected to given loading conditions. This golf ball exhibits a low spin rate on shots, enabling the flight performance of the ball to be improved.

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 land areas are formed with a coat having a high coefficient of friction and the dimple areas have a surface energy of not more than 32 dynes, 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 includes a core, a mid layer, and a cover. A ratio R1 calculated by mathematical formula (1): R1=(Df1−Df2)/(Df2−Df3) is not less than 5.00. A ratio R2 calculated by mathematical formula (2): R2=(T2*H2)/H3 is not less than 2.00. A ratio R3 calculated by mathematical formula (3): R3=D1/T3 is not less than 50. In mathematical formulas (1) to (3), Df1 represents an amount of compressive deformation of the core, Df2 represents an amount of compressive deformation of a sphere including the core and the mid layer, Df3 represents an amount of compressive deformation of the golf ball, T2 represents a thickness of the mid layer, H2 represents a hardness of the mid layer, H3 represents a hardness of the cover, D1 represents a diameter of the core, and T3 represents a thickness of the cover.

A golf ball includes a core, a mid layer, and a cover. A ratio R1 calculated by mathematical formula (1): R1=(Df1−Df2)/(Df2−Df3) is not less than 5.00. A ratio R2 calculated by mathematical formula (2): R2=(T2*H2)/H3 is not less than 2.00. A ratio R3 calculated by mathematical formula (3): R3=D1/T3 is less than 50. In mathematical formulas (1) to (3), Df1 represents an amount of compressive deformation of the core, Df2 represents an amount of compressive deformation of a sphere including the core and the mid layer, Df3 represents an amount of compressive deformation of the golf ball, T2 represents a thickness of the mid layer, H2 represents a hardness of the mid layer, H3 represents a hardness of the cover, D1 represents a diameter of the core, and T3 represents a thickness of the cover.

A golf ball having a single-layer rubber core, a single-layer resin cover and one intermediate layer therebetween satisfies the following conditions:

(Shore C hardness at surface of intermediate layer-encased sphere)>(Shore C hardness at ball surface),

(Atti compression of core)/(Shore C hardness at core surface−Shore C hardness at core center)≤1.1, and

(Shore C hardness at surface of intermediate layer-encased sphere)/{(Shore C hardness at core surface−Shore C hardness at core center)×intermediate layer thickness (mm)}≤2.7.

This ball has a superior distance performance on full shots with an iron and a high spin performance in the short game, imparts a very soft feel and possesses an excellent durability to cracking on repeated impact. The ball is intended to satisfy the needs of skilled amateur golfers who handle iron shots skillfully.

In a golf ball for professional golfers and skilled amateurs which has a single-layer core, a cover and at least one intermediate layer therebetween, the sphere obtained by encasing the core with the intermediate layer (intermediate layer-encased sphere) and the ball have a surface hardness relationship which satisfies the condition:

(surface hardness of intermediate layer-encased sphere)>(surface hardness of ball).

The core has a diameter of from 35.5 to 39.5 mm and a distinctive hardness profile that satisfies specific conditions. The ball is endowed with both an excellent flight performance and excellent durability to repeated impact.

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.