Multi-layered golf balls containing a dual-core structure are provided. The core structure includes an inner core (center) comprising a foam composition, preferably foamed polyurethane. The outer core layer is preferably formed from a non-foamed thermoset composition such as polybutadiene rubber. The core layers have different hardness and specific gravity levels. The specific gravity (density) of the foam inner core is preferably less than the density of the outer core layer. The core assembly preferably has a positive hardness gradient extending across the entire assembly. The core structure and resulting ball have relatively good resiliency.

Casing compositions including carboxylic acid groups, cover compositions including an adhesion promoter with functional groups that crosslink with carboxylic acid groups, and golf balls made from such compositions that have crosslinks between functional groups of the cover compositions and the carboxylic acid groups. 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. Additionally, methods of crosslinking casing and cover layers made from such casing and cover compositions to increase interlayer adhesion are disclosed.

An object of the present invention is to provide a golf ball resin composition excellent in resilience. Another object of the present invention is to provide a golf ball excellent in rebound resilience and shot feeling. The present invention provides a golf ball resin composition comprising: (A) at least one resin component selected from the group consisting of (a-1) a binary copolymer, (a-2) a binary ionomer resin, (a-3) a ternary copolymer, and (a-4) a ternary ionomer resin, (B) a saturated fatty acid, and (C) an unsaturated fatty acid, wherein a total content of (B) the saturated fatty acid and (C) the unsaturated fatty acid ranges from 100 parts by mass to 200 parts by mass with respect to 100 parts by mass of (A) the resin component.

Golf ball comprising: a subassembly; a moisture barrier film layer having a continuous and substantially uniform thermoformed thickness of less than 0.020 inches and consisting of first and second heat-induced pre-form film half shells having first and second inner surfaces that are sized, shaped and contoured to receive and conformally and adhesively mate onto and about the subassembly such that the moisture barrier film layer has a normalized Moisture Vapor Transmission Rate (nMVTR) of less than 4.0 g/(m2.Math.day); and at least one outer layer disposed about an outer surface of the moisture barrier film layer that has an nMVTR greater than the nMVTR of the moisture barrier film layer. Alternatively, the thermoformed thickness is from about 0.003 inches to less than 0.020 inches; or 0.0035 inches to 0.010 inches; or from about 0.01 inches to less than 0.020 inches; or from greater than about 0.0035 inches to 0.005 inches.

Provided is a golf ball having a matte surface with improved visibility. Since the golf ball has a matte surface in comparison with a golf ball having a glossy surface of the related art, the golf ball has an advantage of preventing the golfer from being dazzled caused by reflection of a dimple surface. Since the golf ball has a relatively high luminance value in comparison with a golf ball having a matte surface of the related art, the golf ball has an advantage of being seen to be larger. Since the amount of light remaining in a dimple cover is increased, fluorescent characteristics of a fluorescent material is improved, so that beautiful colors and improved visibility can be achieved. Therefore, it is possible to improve golfers' performance.

Multi-piece golf balls containing a dual-core structure are provided. The core structure includes an inner core (center) comprising a foam composition, preferably foamed polyurethane. The outer core layer is preferably formed from a non-foamed thermoset composition such as polybutadiene rubber. The inner and outer core layers can have different hardness gradients. Preferably, the specific gravity (density) of the foam inner core is less than the density of the outer core layer. The ball further includes a cover of at least one layer and may include at least one casing layer. The core structure and resulting ball have relatively good resiliency.

An object of the present invention is to provide a golf ball resin composition excellent in resilience. Another object of the present invention is to provide a golf ball excellent in rebound resilience and shot feeling. The present invention provides a golf ball resin composition comprising: (A) at least one resin component selected from the group consisting of (a-1) a binary copolymer, (a-2) a binary ionomer resin, (a-3) a ternary copolymer, and (a-4) a ternary ionomer resin, (B) a saturated fatty acid, and (C) an unsaturated fatty acid, wherein a total content of (B) the saturated fatty acid and (C) the unsaturated fatty acid ranges from 100 parts by mass to 200 parts by mass with respect to 100 parts by mass of (A) the resin component.

A golf ball includes a core having an outer surface and a geometric center. The core is formed from a substantially homogenous rubber composition. An ionomeric inner cover layer is formed about the core and has a material hardness of about 60 Shore D or greater. The golf ball includes an outer cover layer formed from a polyurea or a polyurethane and having a material hardness of about 60 Shore D or less. The outer surface of the core has a trans content of about 12% or less and a hardness of about 71 to 88 Shore C. The geometric center of the core has a trans content of about 10% or less and a hardness of about 60 to 80 Shore C. The core has an outer surface hardness greater than a geometric center hardness by about 5 to 19 Shore C to define a positive hardness gradient.

Multi-piece golf balls containing a dual-core structure are provided. The core structure includes an inner core (center) comprising a foam composition, preferably foamed polyurethane. The outer core layer is preferably formed from a non-foamed thermoset composition such as polybutadiene rubber. The inner and outer core layers can have different hardness gradients. Preferably, the specific gravity (density) of the foam inner core is less than the density of the outer core layer. The ball further includes a cover of at least one layer and may include at least one casing layer. The core structure and resulting ball have relatively good resiliency.

Multi-piece golf balls containing a multi-layered core structure are provided. The core structure includes a small, heavy inner core (center) having a relatively high specific gravity, an intermediate core layer, and a surrounding outer core layer. The layers of the core structure may have different hardness gradients. In one preferred embodiment, each core layer has a positive hardness gradient. The center of the core comprises a metal material such as copper, steel, brass, tungsten, titanium, aluminum, and alloys thereof. The intermediate core layer is preferably formed from a first thermoset composition such as polybutadiene rubber, and the outer core layer is preferably formed from a second thermoset composition. The resulting ball has high resiliency and good spin control.