Method of making golf ball comprising providing subassembly and forming at least one layer thereabout comprised of a thermoset polyurethane created using prepolymer prepared by: reacting stoichiometric excess of first isocyanate with at least one long chain polyol and/or polyamine soft segment to create first isocyanate-terminated first prepolymer with (% NCO).sub.FIRST PREPOLYMER; and adding stoichiometric excess of additional isocyanate to the first isocyanate-terminated first prepolymer to produce modified-first prepolymer with (% NCO).sub.MODIFIED-FIRST PREPOLYMER; wherein (% NCO).sub.MODIFIED-FIRST PREPOLYMER>(% NCO).sub.FIRST PREPOLYMER. Reacting a stoichiometric excess of isocyanate in multiple steps and staggering addition of total amount of free, reactive, and unreacted isocyanate functional groups into the isocyanate-functional final prepolymer produces an improved final prepolymer as well as a resulting thermoset polyurethane with better physical properties compared with conventional thermoset polyurethanes based on conventional prepolymers wherein the total % NCO is added in a single step or not at all until well into the prepolymer formation process.

Method of making a golf ball comprising the steps of: providing a subassembly; forming about the subassembly at least one layer comprised of a thermoset polyurethane which is prepared by mixing as the essential ingredients: (i) at least one long chain soft segment polyol and/or polyamine; (ii) at least one short chain-extending-type species; (iii) at least one isocyanate; and (iv) at least one additional chain-extending-type species; wherein essential ingredients (i) and (ii) are combined (reacted/mixed) to form a first sub-mixture; followed by combining/mixing the first sub-mixture and essential ingredient (iii) to form a prepolymer second sub-mixture; followed by combining (reacting/mixing) the prepolymer second sub-mixture with essential ingredient (iv) to form the thermoset polyurethane. Essential ingredients (ii) and (iv) may differ, or in some embodiments, are the same, although the total amount of essential ingredients (ii) included is preferably greater than the total amount of essential ingredient (iv).

The use of a low molecular weight farnesene, poly(farnesene), and farnesene copolymer in a golf ball is disclosed herein. In a core, low molecular weight farnesene, poly(farnesene) or farnesene copolymer is blended with 1,4 polybutadiene or a polyalkenamer. In a mantle layer, low molecular weight farnesene, poly(farnesene), and/or farnesene copolymer can be blended with non- or partially neutralized copolymeric or terpolymeric ionomer(s). In a cover, low molecular weight farnesene, poly(farnesene), and farnesene copolymer can be blended with highly neutralized ionomer.

Multi-piece golf balls having a multi-layered solid core and multi-layered cover are provided.

Disclosed is a carbon nanotube golf ball having improved hitting feel and durability, and antistatic property comprising: a core having CNT/ionomer-dispersion; a cover formed on the core; and an antistatic finish on the top cover. Herein, CNT/ionomer-dispersions having a diameter of 10 to 3,000 m are produced in advance using an independent process, and then applied to the present art. The top cover is provided with antistatic finish using a CNT coating solution for keeping the clean surface during the golf play.

A golf ball with a cover or mantle layer that comprises a polyurethane and ionomer hybrid made by compounding or dry blending acid functional polyurethane and an ionomer is disclosed herein. The golf ball comprises a core (single core or dual core), a mantle layer (single layer or dual layer) and a cover layer.

Golf ball incorporating polyurethane mixture having wt. % NCO content of 4-20 and including a prepolymer polyol portion comprised of trans--Farnesene diol(s) in an amount of about 3-70 wt. % of total weight of prepolymer. Trans--Farnesene diol may be 15 carbon, long chain, branched, unsaturated 3,4-vinyl-containing bio-hydrocarbon having the formula: ##STR00001## Prepolymer can include a 1:99 to 99:1 blend (wt. % ratio) of Trans--Farnesene diol(s) and polybutadiene-based polyol(s) in an amount of about 35-85 wt. %, along with about 15 wt. %-65 wt. % of diisocyanate(s). Curative may be combined with prepolymer in amount of about 3-25 wt. % of total weight of curative and prepolymer combined, and may be mixture of aromatic diamine(s) and white dispersion in a wt. % ratio of about 90:10 to 50:50, plus catalyst. Hardness of polyurethane mixture can be from 75. Shore A to 75 Shore D or a material hardness can be from about 40 Shore D to about 65 Shore D.

Multi-piece golf balls having a multi-layered solid core and multi-layered cover are provided.

Multi-layered golf balls containing a dual-core structure are provided. The core structure includes an inner core (center) made from a foam or metal-containing composition, or it has a hollow shell construction, and the outer core layer is made of a thermoplastic composition. Preferably, the thermoplastic composition comprises: a) ethylene acid copolymer, b) plasticizer, and c) cation source. A fatty acid ester such as ethyl oleate is preferably used as the plasticizer. The core assembly preferably has a positive hardness gradient extending across the entire assembly. The core structure and resulting ball have relatively good resiliency at given compressions.

Multi-layered golf balls having a core, intermediate layer, and cover are provided. The ball includes a non-foamed inner core (center) made of a thermoplastic or thermoset composition such as polybutadiene rubber. An intermediate layer comprising a foamed composition, such as polyurethane foam, is disposed about the inner core. The foamed intermediate layer may have a specific gravity gradient within the layer, wherein the outer surface specific gravity is greater than the midpoint specific gravity. Ball constructions having two intermediate layers, wherein at least one layer is a foamed layer can be made. A cover having at least one layer is disposed about the intermediate layer.