The invention provides a method of manufacturing a golf ball having a core and a cover of one or more layer over the core, wherein an outermost layer of the cover is molded of a thermoplastic material selected from the group consisting of polyurethane, polyurea and mixtures thereof. The method includes at least the following steps (1) and (2): (1) treating a surface of the cover with an isocyanate compound; and (2) washing off and physically removing excess isocyanate compound by blasting the cover surface with a specific substance at high pressure.

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 (I) a polyurethane or a polyurea and (II) an aromatic vinyl elastomer, the amount of component (II) included per 100 parts by weight of component (I) is less than 15 parts by weight, and the CS.sub.1 value calculated by formula (1) below

[00001]$\begin{array}{cc}C{S}_1=\left(C{V}_{50}-C{V}_{12}\right)/38& \left(1\right)\end{array}$

(wherein CV.sub.50 is the coefficient of restitution at an incident velocity of 50.0 m/s and CV.sub.12 is the coefficient of restitution at an incident velocity of 12.0 m/s) is larger than 4.0810.sup.3, so that the golf ball has both an excellent controllability and a good feel at impact on approach shots together with a good scuff resistance.

Multi-layer golf ball cores having positive hardness and compression gradients and golf balls including these cores are disclosed. The hardness, compression, and diameter relationships in the core assemblage components help to reduce the spin rate of the ball off the driver while still providing desirable performance characteristics in and around the green.

Multi-layered golf ball core sub-assemblies and the resulting golf balls are provided. The core structure includes an inner core (center) comprising a foam composition, preferably foamed polyurethane. The intermediate and outer core layers are preferably formed from foamed and non-foamed thermoset compositions. For example, the intermediate core can be formed from a thermoset rubber so there are adjoining foam core layers (inner and intermediate) and the outer core layer can be formed from a non-foamed thermoset rubber. The core layers have different hardness and specific gravity levels. The core assembly preferably has a positive hardness gradient extending across the entire assembly. The core structure and resulting ball have relatively good resiliency.

Multi-layered golf balls having at least one layer made of a foamed silicone composition are provided. Multi-layered golf balls having at least one layer made of non-foamed silicone elastomer composition also are provided. For example, three-piece, four-piece, and five-piece golf balls containing different core and cover structures can be made. The foamed silicones have good thermal stability and durability without sacrificing resiliency. The non-foamed silicone elastomers have high elongation, tensile strength, chemical/fluid-resistance, and weatherability properties. These compositions can be used to form any layer, for example, core, intermediate, or cover, in the golf ball.

The invention provides a method of manufacturing a golf ball having a core and a cover of one or more layer over the core, wherein an outermost layer of the cover is molded of a thermoplastic material selected from the group consisting of polyurethane, polyurea and mixtures thereof. The method includes at least the following steps (1) and (2): (1) treating a surface of the cover with an isocyanate compound; and (2) washing off and physically removing excess isocyanate compound by blasting the cover surface with a specific substance at high pressure.

A golf ball comprising: (A) a core; (B) optionally, at least one intermediate layer; and (C) a cover layer, wherein the cover layer or the intermediate layer comprises a polyurethane-urea composition that is the reaction product of: (i) a thermoplastic polyurethane-urea formed as a reaction product of (a) a diol or polyol, (b) a first isocyanate, and (c) an amine chain extender; and (ii) a crosslinking agent.

Casing compositions including carboxyl groups, cover compositions including nucleophile groups and an adhesion promoter capable of crosslinking carboxyl and nucleophile groups, and golf balls made from such compositions that have crosslinks between carboxyl groups in the casing composition and nucleophile groups in the cover composition. The nucleophile groups may be hydroxyl groups, amino groups, or other types of nucleophile groups. The adhesion promoter may be a polyaziridine. An acid catalyst may be used to facilitate the reaction between the nucleophile groups in the cover composition and the adhesion promoter. The type and concentration of the components in the casing and cover compositions, including the adhesion promoter, affect the adhesion between golf balls having components made from such compositions and, thus, can be used to produce a golf ball having increased durability.

Thermoplastic and thermoset compositions including hydroxyurethane linkages, golf ball components formed using such thermoplastic or thermoset compositions, and golf balls including such golf components.

A golf ball that includes at least one core, and a cover layer formed from a cast polyurethane or polyurea, wherein the cover layer defines a first surface area portion of a uniform first color and a second surface area portion of a uniform second color, and a seam between the first surface area portion and the second surface area portion, wherein the first color is different than the second color.