In a golf ball having a core, a cover and at least one intermediate layer between the core and the cover, the core is made of a material molded under heat from a rubber composition that includes (a) a base rubber, (b) a co-crosslinking agent which is an α,β-unsaturated carboxylic acid and/or a metal salt thereof, (c) an organic peroxide, (d) water, and (e) an antioxidant which is a benzimidazole of a specific formula and/or a metal salt thereof. The core and ball have compressive deformations within specific respective ranges when subjected to given loading conditions. This golf ball exhibits a low spin rate on shots, enabling the flight performance of the ball to be improved.

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.

In an aspect, a sports ball includes a core including a negative Poisson's ratio (NPR) foam material, in which the core has a Poisson's ratio of between 0 and −1, and in which the NPR foam material includes an NPR polymer foam; and a cover layer surrounding the core. In an aspect, a golf club includes an elongated shaft; a grip disposed at a first end of the elongated shaft; and a head connected to a second end of the elongated shaft, the head having a flat face configured for contact with a golf ball, in which the flat face is formed of a negative Poisson's ratio (NPR) foam material, in which the head has a Poisson's ratio of between 0 and −1, and in which the NPR foam material includes an NPR metal foam, an NPR ceramic foam, or an NPR-PPR composite foam.

The presently disclosed subject matter is directed to a golf ball providing improve play characteristics. The disclosed golf ball includes an outer cover comprising a plurality of divots. The disclosed golf ball further includes a central core comprising one or more lightweight materials, such as aerogel. The combination of the lightweight core and the unique divots enable the golf ball to go farther and straighter when hit by the golfer, thereby providing increased performance.

A formulation for making at least one element of a golf ball, wherein the formulation includes: (i) from 50 weight percent to 95 weight percent of a thermoplastic composition comprising: (1) at least one ethylene acid copolymer consisting essentially of copolymerized comonomers of: (A) ethylene, and (B) from 5 weight percent to 25 weight percent of at least one α,β-ethylenically unsaturated carboxylic acid having from 3 carbon atoms to 8 carbon atoms, based on the total weight of monomers present in the ethylene acid copolymer; wherein the acid moieties of component (1) are neutralized to a level of from 25 percent to 220 percent; and (ii) from 5 weight percent to 50 weight percent of a crosslinked material having a gel content of at least 80 weight percent, wherein the crosslinked material is a crosslinked elastomer, a crosslinked rubber, or a blend of a crosslinked elastomer and a crosslinked rubber; a process for making the above formulation; at least one element of a multilayer golf ball and a process for making the at least one element of a multilayer golf ball using the above formulation; a multilayer golf ball including (a) at least one core, and (b) a cover; wherein the at least one core is made from the above formulation; and a process of manufacturing the above multilayer golf ball.

Golf balls including a plurality of radar detectable marks disposed on any single layer or among two or more layers thereof are provided. When all of the radar detectable marks present on any layer of the ball are radially projected onto the outer surface of the ball, the resulting overall pattern of projected radar detectable marks includes a series of three or marks located on a 1.5 mm wide great circle band on the outer surface of the ball.

A system for measuring golf ball trajectory characteristics is disclosed. The system includes artificial grass with a launch location for a golf ball and a plurality of wide-angle distance optical sensors mechanically connected to the artificial grass positioned such that a field of measurement of each wide-angle distance optical sensors intersects. The system also includes a central processing unit connected to the wide-angle distance optical sensors, the central processing unit configured to collect distance measurements from the wide-angle distance optical sensors and to determine a velocity of a trajectory of the golf ball from the launch location to the intersection of the field of measurement of each wide-angle distance optical sensors given a distance between the plurality of the wide-angle distance optical sensors, a distance between the plurality of the wide-angle distance optical sensors and the launch location, and the distance measurements from the plurality of the wide-angle distance optical sensors. Once the velocity of the trajectory of the golf ball is determined, the central processing unit transmits the velocity to a display.

A golf ball having a single-layer rubber core, a single-layer resin cover and one intermediate layer therebetween satisfies the following conditions:

(Shore C hardness at surface of intermediate layer-encased sphere)>(Shore C hardness at ball surface),

(Atti compression of core)/(Shore C hardness at core surface−Shore C hardness at core center)≤1.1, and

(Shore C hardness at surface of intermediate layer-encased sphere)/{(Shore C hardness at core surface−Shore C hardness at core center)×intermediate layer thickness (mm)}≤2.7.

This ball has a superior distance performance on full shots with an iron and a high spin performance in the short game, imparts a very soft feel and possesses an excellent durability to cracking on repeated impact. The ball is intended to satisfy the needs of skilled amateur golfers who handle iron shots skillfully.

Golf balls including a plurality of radar detectable marks disposed on any single layer or among two or more layers thereof are provided. When all of the radar detectable marks present on any layer of the ball are radially projected onto the outer surface of the ball, the resulting overall pattern of projected radar detectable marks includes a series of three or marks located on a 1.5 mm wide great circle band on the outer surface of the ball.

An object of the present disclosure is to provide a golf ball having excellent durability and flight distance and good shot feeling for an average golfer who hits a golf ball at a slow head speed. The present disclosure provides a golf ball comprising a spherical core and at least two cover layers covering the spherical core, wherein a difference between a core surface crosslinking density and a core center crosslinking density is more than 1.0×10.sup.2 mol/m.sup.3 and less than 9.0×10.sup.2 mol/m.sup.3, a hardness difference between a core surface hardness Cs (Shore C hardness) and a core center hardness Co (Shore C hardness) is 13.0 or more and 30.0 or less, a compression deformation amount of the core when applying a load from an initial load of 98 N to a final load of 1275 N to the core is 3.8 mm or more, and the at least two cover layers include a first cover layer and a second cover layer positioned closer to the spherical core than the first cover layer, an average hardness Dave=(Ti×Hi+To×Ho)/(Ti+To) of the first cover layer and the second cover layer is 55 or more, where To (mm) is a thickness of the first cover layer, Ho (Shore D) is a slab hardness of the first cover layer, Ti (mm) is a thickness of the second cover layer, and Hi (Shore D) is a slab hardness of the second cover layer.