The invention provides a golf ball having a core and a cover of one or more layer encasing the core, wherein the core has a center core and a foamed outer layer that directly, or indirectly through another layer, envelops the center core. The foamed outer layer is made of a rubber composition that includes a base rubber, a co-crosslinking agent and an organic peroxide. The foamed outer layer has an inside portion facing the ball center and an outside portion facing the outside of the ball that are unfoamed regions, and contains a foamed region in an intermediate portion therebetween. A method of manufacturing such a golf ball is also provided.

A method of manufacturing golf balls having a core and a cover of at least one layer encasing the core includes the steps of producing a core by molding and vulcanizing a rubber composition containing (A) a base rubber, (B) an ,-unsaturated carboxylic acid and/or a metal salt thereof, and (C) an organic peroxide; and heat-treating the core for 1 to 24 hours at between 175 and 300 C. Golf balls which undergo little energy loss and have a high initial velocity can be obtained by this method.

Golf balls having covers made of thermoplastic polyurethane compositions are provided. Multi-piece golf balls can be made. In one embodiment, the outer cover layer is formed from a composition comprising a thermoplastic polyurethane and multi-functional hydroxyl compound. Mixtures of multi-functional amines and imines, and multi-functional isocyanates, and solvent, can be applied to the outer cover to form at least a partially cross-linked cover. The cover composition can further include catalysts, ultraviolet (UV)-light stabilizers, and other additives. The coating methods have many benefits and the finished balls have good physical properties.

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.

Golf balls comprising a multi-layer core and a cover are disclosed. The multi-layer core comprises a center, an intermediate core layer, and an outer core layer. At least one layer of the multi-layer core is a high specific gravity layer.

In a golf ball having a core, a cover of at least one layer and a paint film layer formed on a surface of the cover, the paint film layer has an elastic work recovery of at least 60%, the cover layer in contact with the paint film layer has a material hardness on the Shore D scale of at least 55 and, letting M be the elastic work recovery (%) of the paint film layer and N be the material hardness (Shore D hardness) of the cover layer, MN>0. The ball surface is scratch-resistant and has an excellent durability, and the ball has a reduced spin rate on shots with a driver or a long iron, resulting in an increased carry.

A polyurethane-ionomer hybrid resin composition for a golf ball cover having excellent elastic reaction force and backspin performance comprises 100 parts by weight of a modified ionomer having a number average molecular weight in a range of 1,000 to 2,400, provided as a reaction product generated by a reaction among a polyol including hydroxyl groups on opposing ends of the polyol, a monomer of acrylic acid or methacrylic acid having 2 to 3 functional groups, and zirconia, and modified in such a manner that a polyester oligomer in a zirconia complex state and a zirconia filled state is added to an ionomer resin to be reacted, and a portion of unsaturated carboxylic acid of an ionomer is neutralized to be zirconium and additionally polymerized to be the polyester oligomer; 20 to 40 parts by weight of a block polyurethane prepolymer with respect to 100 parts by weight of the modified ionomer; 70 to 100 parts by weight of the ionomer with respect to 100 parts by weight of the modified ionomer; and 1 to 10 parts by weight of a chain extender with respect to 100 parts by weight of the block polyurethane prepolymer.

A golf ball includes a main body and a paint layer positioned outside the main body. The paint layer includes an inner layer and an outer layer positioned outside the inner layer. When an indentation depth (nm) is measured on a cross-section along a plane passing through a central point of the golf ball when a force of 30 mgf is applied to the cross-section in a direction perpendicular to the cross-section, an indentation depth Di on a cross-section of the inner layer is smaller than an indentation depth Do on a cross-section of the outer layer. A thickness To of the outer layer is larger than a thickness Ti of the inner layer.

Golf ball having CoR of at least 0.700 and Atti compression of at least about 50 and comprising layer comprising a mixture of ionomer composition and a plurality of particulates, at least some being surface-treated with alkoxylated siloxanes and/or polyether-modified siloxanes, and selected from titanium dioxide particles, barium sulfate particles, zinc sulfide particles, and/or zinc oxide particulates. At least some particulates may be contacted with compound having the formula:

##STR00001##

Compound (I) may be included in amount of 0.01 to 2% by weight based on total weight of portion of plurality being contacted. The plurality may be included in mixture in amount such that the layer has specific gravity of from 0.5 to about 5.0, tensile strength of from about 300 psi to about 50,000 psi, and elongation at break of from about 20% to about 1000%, each being greater than that of the ionomer composition portion of the mixture.

Golf balls having covers made of thermoplastic polyurethane compositions are provided. Multi-piece golf balls can be made. In one embodiment, the outer cover layer is formed from a composition comprising a thermoplastic polyurethane and epoxy compound. Mixtures of multi-functional amines and imines, and multi-functional isocyanates, and epoxy curing agents; and solvent, can be applied to the outer cover. The resulting coating may contain polyurethanes, polyureas, and hybrids, copolymers, and blends thereof. The cover composition and surface coatings can further include catalysts, ultraviolet (UV)-light stabilizers, and other additives. The coating methods have many benefits and the finished balls have good physical properties.