An object of the present disclosure is to provide a golf ball having excellent durability and an increased spin rate on driver shots to travel a suppressed flight distance. The present disclosure provides a golf ball comprising a spherical constituent member, wherein the spherical constituent member is formed from a rubber composition containing (a) a rubber component containing a natural rubber, (b) a co-crosslinking agent, (c) a crosslinking initiator, and (d) an organic sulfur compound, a center hardness (Ho) of the spherical constituent member is 65 or more in Shore C hardness, a hardness difference (Hs?Ho) between a surface hardness (Hs) and the center hardness (Ho) of the spherical constituent member is less than 16 in Shore C hardness, and an absolute value of a hardness difference (Hs?H50) between the surface hardness (Hs) of the spherical constituent member and a hardness (H50) at a 50% point of a radius of the spherical constituent member from a center of the spherical constituent member is 10 or less in Shore C hardness.

An object of the present disclosure is to provide a golf ball having a great change in an initial velocity associated with a change in a swing speed. The present disclosure provides a golf ball comprising a constituent member, wherein at least a part of the constituent member is formed of a cured product of a rubber composition comprising (a) a base rubber containing a natural rubber, (b) a co-crosslinking agent containing methacrylic acid and/or a metal salt thereof and (c) a crosslinking initiator.

An object of the present disclosure is to provide a novel golf ball aiming at realization of a sustainable and better society and having a low spin rate on driver shots. The present disclosure provides a golf ball comprising a spherical constituent member, wherein the spherical constituent member is formed from a rubber composition containing (a) a rubber component containing a natural rubber, (b) a co-crosslinking agent, (c) a crosslinking initiator, and (d) an organic sulfur compound, a surface hardness (Hs) of the spherical constituent member is 75 or more in Shore C hardness, a hardness difference (Hs?H75) between the surface hardness (Hs) of the spherical constituent member and a hardness (H75) at a 75% point of a radius of the spherical constituent member from a center of the spherical constituent member is 3 or more and 10 or less in Shore C hardness, and a hardness difference (Hs?Ho) between the surface hardness (Hs) and a center hardness (Ho) of the spherical constituent member is 16 or more in Shore C hardness.

An object of the present disclosure is to provide a golf ball having lowered resilience while maintaining the hardness of the golf ball. The present disclosure provides a golf ball comprising a constituent member, wherein at least a part of the constituent member is formed from a cured product of a rubber composition containing (a) a base rubber, (b) a co-crosslinking agent and (c) a crosslinking initiator, (a) the base rubber contains (a1) a natural rubber and a grafting ratio of (b) the co-crosslinking agent in the cured product of the rubber composition ranges from 40 mass % to 80 mass %.

Disclosed herein are heterogeneous golf ball compositions comprising a matrix formed from a thermosetting polymer composition and discrete particles of crosslinked rubber dispersed within the matrix.

Golf balls and golf ball components made using three-dimensional (3D) additive manufacturing systems are provided. The golf ball includes at least one three-dimensional piece. Preferably, a continuous liquid interface printing method is used to make the three-dimensional structure. Ultraviolet (UV)-light polymerizable materials are used in the method. The method may be used to make single-piece or multi-piece balls. For example, the ball may include an inner core produced by the liquid interface printing method. An outer core layer may be disposed about the inner core, and a cover comprising inner and outer cover layers may encapsulate the core assembly to form the finished golf ball. The outer core and cover layers may be made using conventional molding technologies or the methods of this invention.

Disclosed herein are heterogeneous golf ball compositions comprising a matrix formed from a thermosetting polymer composition and discrete particles of crosslinked rubber dispersed within the matrix.

Methods for making golf balls and golf ball components using three-dimensional (3D) additive manufacturing systems are provided. The golf ball includes at least one three-dimensional piece. Preferably, a continuous liquid interface printing method is used to make the three-dimensional structure. Ultraviolet (UV)-light polymerizable materials are used in the method. The method may be used to make single-piece or multi-piece balls. For example, the ball may include an inner core produced by the liquid interface printing method. An outer core layer may be disposed about the inner core, and a cover comprising inner and outer cover layers may encapsulate the core assembly to form the finished golf ball. The outer core and cover layers may be made using conventional molding technologies or methods of this invention.

A golf ball with an aerodynamic design is disclosed herein. The aerodynamic design has a protrusion at a center of a hex geometry representing an increase in ball radius greater than 0.0005 inches from a minimum ball radius. The minimum ball radius is located between 0.01 and 0.04 inch (11%-46%) from the center of the hex geometry.

An object of the present invention is to provide a golf ball having good spin performance on approach shots and good shot feeling as well as excellent stain resistance by precisely controlling physical properties of a paint film actually formed on a surface of a golf ball body. The present invention provides a golf ball comprising a golf ball body and a paint film formed on a surface of the golf ball body, wherein the paint film is such that a linear approximation curve obtained by a least square method has a slope in an absolute value ranging from 0.0001 to 0.0020 when a loss tangent tan thereof measured by a nanoindentation method is plotted as a vertical axis against a measuring frequency (Hz) as a horizontal axis, and that an elastic modulus thereof measured by a nanoindentation method ranges from 0.040 GPa to 0.600 GPa.