In a golf ball having a rubber core of at least one layer and a cover of at least one layer encasing the core, at least one layer of the cover is formed of a resin composition that includes (A) polyurethane or polyurea, and (B) a thermoplastic polyester elastomer. Component (B) is included in a ratio of not more than 45 wt % of the overall amount of the resin composition, and the resin composition has a Shore D hardness of 42 or less and a rebound resilience of from 60 to 72%. The golf ball has an excellent controllability on approach shots, is able to maintain a good feel at impact and a good scuff resistance, and also has a good moldability.

In a golf ball having a core and a cover of one or more layer, at least one layer of the cover is formed of a resin composition which includes in a specific weight ratio: (I) a thermoplastic polyurethane resin that uses polytetramethylene glycol having a number-average molecular weight of from 1,900 to 2,100 as the polyol component, (II) a thermoplastic polyurethane resin that uses polytetramethylene glycol having a number-average molecular weight of from 900 to 1,100 as the polyol component, and (III) an aromatic vinyl elastomer. The cover layer formed of this resin composition has a Martens hardness and an elastic work recovery which together satisfy a specific formula. The golf ball has an excellent controllability on approach shots without losing distance on driver shots. In addition, the scuff resistance and moldability are good.

An object of the present invention is to provide a golf ball having an excellent flight performance on driver shots. The present invention provides a golf ball comprising a spherical core and at least one cover covering the spherical core, wherein a hardness difference D1 (H75−H0) between a hardness H75 at a point radially located at a distance of 75% from a center of the spherical core and a center hardness H0 of the spherical core is 10 or more and 27 or less in Shore C hardness, and a hardness difference D2 (Hs−H75) between a surface hardness Hs of the spherical core and the hardness H75 at the point radially located at the distance of 75% from the center of the spherical core is 0 or more and 6.5 or less in Shore C hardness.

An object of the present invention is to provide a golf ball having excellent spin performance on approach shots under a wet condition and excellent spin performance on approach shots under a condition that there is grass between the golf ball and the dub face. The present invention provides a golf ball comprising a golf ball body and a paint film composed of at least one layer and formed on a surface of the golf ball body, wherein an outermost layer of the paint film located at the outermost layer of the golf ball contains a base resin and a porous filler, the base resin contains a polyurethane obtained by a reaction between (A) a polyisocyanate composition and (B) a polyol composition containing a urethane polyol as a polyol component, the porous filler contains SiO.sub.2 in an amount of 50 mass % or more as a constituent component, and a loss tangent (tan δ) of the outermost layer of the paint film measured with a dynamic viscoelasticity measuring apparatus under following conditions has a peak temperature in a range of from −43° C. to 40° C.

An object of the present invention is to provide a golf ball having excellent spin performance on approach shots under a wet condition and excellent spin performance on approach shots under a condition that there is grass between the golf ball and the club face. The present invention provides a golf ball comprising a golf ball body and a paint film composed of at least one layer and formed on a surface of the golf ball body, wherein an outermost layer of the paint film located at the outermost layer of the golf ball contains a base resin and a porous filer, the base resin contains a polyurethane obtained by a reaction between (A) a polyisocyanate composition and (B) a polyol composition containing a urethane polyol as a polyol component, the porous filler contains SiO.sub.2 in an amount of 50 mass % or more as a constituent component, and a loss tangent (tan δ) of the outermost layer of the paint film measured with a dynamic viscoelasticity measuring apparatus under following conditions has a peak temperature in a range of from −40° C. to 40° C.

An object of the present invention is to provide a golf ball having excellent spin performance on approach shots under a wet condition and excellent spin performance on approach shots under a condition that there is grass between the golf ball and the club face. The present invention provides a golf ball comprising a golf ball body and a paint film composed of at least one layer and formed on a surface of the golf ball body, wherein an outermost layer of the paint film located at the outermost layer of the golf ball contains a base resin and a porous filer, the base resin contains a polyurethane obtained by a reaction between (A) a polyisocyanate composition and (B) a polyol composition containing a urethane polyol as a polyol component, the porous filler contains SiO.sub.2 in an amount of 50 mass % or more as a constituent component, and a loss tangent (tan ) of the outermost layer of the paint film measured with a dynamic viscoelasticity measuring apparatus under following conditions has a peak temperature in a range of from 40 C. to 40 C.

An object of the present invention is to provide a golf ball having excellent spin performance on approach shots under a wet condition and excellent spin performance on approach shots under a condition that there is grass between the golf ball and the dub face. The present invention provides a golf ball comprising a golf ball body and a paint film composed of at least one layer and formed on a surface of the golf ball body, wherein an outermost layer of the paint film located at the outermost layer of the golf ball contains a base resin and a porous filler, the base resin contains a polyurethane obtained by a reaction between (A) a polyisocyanate composition and (B) a polyol composition containing a urethane polyol as a polyol component, the porous filler contains SiO.sub.2 in an amount of 50 mass % or more as a constituent component, and a loss tangent (tan ) of the outermost layer of the paint film measured with a dynamic viscoelasticity measuring apparatus under following conditions has a peak temperature in a range of from 43 C. to 40 C.

Compositions including a resiliency additive and golf ball components made from such compositions having a tailored Coefficient of Restitution are disclosed. The type and concentration of the constituents in the composition, including the resiliency additive, affects the Coefficient of Restitution of components made from the composition and, thus, can be used to produce a golf ball having desirable performance characteristics.

A method of forming a golf ball is disclosed herein. The method includes injecting a cover mixture into a mold to form a cover mixture comprising a thermoplastic polyurethane resin and a polyahl, subjecting the golf ball to a polyisocyanated solution to create a golf ball with a polyisocyanated cover, and heating the golf ball or polyisocyanated cover to remove a solvent component of the polyisocyanated solution and promote the reaction of the polyisocyanate with the cover mixture and polyahl.

An object of the present invention is to provide a golf ball having an excellent flight performance on driver shots. The present invention provides a golf ball comprising a spherical core and at least one cover covering the spherical core, wherein a hardness difference D1 (H75H0) between a hardness H75 at a point located at a distance of 75% of a core radius from a center of the spherical core and a center hardness H0 of the spherical core is 15 or more and 35 or less in Shore C hardness, a hardness difference D2 (HsH75) between a surface hardness Hs of the spherical core and the hardness H75 at the point located at the distance of 75% of the core radius from the center of the spherical core is 1 or more and 3.5 or less in Shore C hardness, and a hardness difference D3 ((H0+H75)/2H37.5) between a hardness of (the center hardness H0 of the spherical core+the hardness H75 at the point located at the distance of 75% of the core radius from the center of the spherical core)/2 and a hardness H37.5 at a point located at a distance of 37.5% of the core radius from the center of the spherical core is 0.5 or more and 6.5 or less in Shore C hardness.