Dual core golf ball constructions achieving consistent and repeatable concentricity by incorporating/using an assembly of dual core components comprising a solid spherical inner core component and three outer core components that are collectively compression molded about the solid spherical inner core component to create an outer core layer thereabout. The three outer core components include a first half-shell, a second half-shell; and a ring-shaped securing plate such that the solid spherical inner core component is immovably centered within the outer core layer. Each of the first half-shell, the ring-shaped securing plate, and the second half-shell is comprised of the same rubber composition(s) and possess strong cohesive and adhesive bonds at parting lines between the three molded assembly parts and collectively create an outer core layer having one or more uniform property profile, such as a hardness gradient throughout, without interruption at parting lines between the three outer core components.

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.

Golf balls having covers made of thermoplastic polyurethane compositions are provided. Multi-piece golf balls can be made. Polyurethane primer coatings and polyurethane top-coatings are applied to the thermoplastic polyurethane cover. Different coating methods can be used. Isocyanate-rich and polyol-rich polyurethane coatings can be applied. In one embodiment, the golf ball can be treated with a multi-functional isocyanate prior to applying the coatings. The polyurethane cover composition and surface coatings can further include catalysts, ultraviolet (UV)-light stabilizers, and other additives. Heat is used to cure the coatings. The coating methods have many benefits and the finished balls have good physical properties.

A golf ball with improved durability is disclosed herein. The golf ball has a core comprising a polybutadiene material and methyl methacrylate, butadiene, styrene (MBS) with a weight percentage of MBS ranging from 0.5 to 5 weight percent of the core.

A resin composition for golf balls includes (a) an acid-containing copolymer having an amount of acid constituent per 100 wt % of the sum of monomer units in the copolymer that is from 1 to 30 wt %, and (b) an amine-containing polymer having a branched structure. The resin composition imparts golf balls with an excellent rebound resilience and also confers an outstanding durability to repeated impact and an outstanding scuff resistance, making it particularly useful as a cover material in golf balls.

In a golf ball having a core, envelope layer, intermediate layer and cover, the (core diameter)/(ball diameter) value falls within a particular range, the core has a specific hardness profile, the intermediate layer is formed primarily of an ionomer resin material including a high-acid ionomer resin, and the Shore C hardness relationships among the core center and surface hardnesses and the surface hardnesses of the envelope layer-encased sphere, intermediate layer-encased sphere and ball satisfy the following conditions: (1) core surface hardness<surface hardness of envelope layer-encased sphere<surface hardness of intermediate layer-encased sphere>ball surface hardness, (2) (surface hardness of envelope layer-encased sphere)−(core center hardness)≥28. Also, the intermediate layer and cover have respective thicknesses which satisfy the condition: (3) cover thickness<intermediate layer thickness. This ball enables mid-level and skilled amateur golfers to achieve superior distances on driver shots and on iron shots, and moreover has a soil yet good feel at impact.

A golf ball with a core comprising polybutadiene and graphene is disclosed herein. The golf ball has a single core comprising polybutadiene and graphene. Alternatively, the golf ball has a dual core with an inner core comprising polybutadiene and graphene. Alternatively, the golf ball has a dual core with an outer core comprising polybutadiene and graphene.

An object of the present invention is to provide a golf ball having excellent durability and good shot feeling. The present invention provides a golf ball comprising a core, wherein a difference (crosslinking density at surface of core-crosslinking density at center of core) between a crosslinking density at a surface of the core and a crosslinking density at a center of the core is more than 1.0×10.sup.2 mol/m.sup.3 and less than 9.0×10.sup.2 mol/m.sup.3, and a hardness difference (Hs−Ho) between Hs and Ho is 13.0 or more and 30.0 or less, and the core satisfies H50−Ho>Hs−H50, wherein Hs (Shore C hardness) is a hardness at the surface of the core, Ho (Shore C hardness) is a hardness at the center of the core, and H50 (Shore C hardness) is a hardness at a midpoint between the center of the core and the surface of the core.

A rubber composition for golf balls includes (A) a base rubber, (B) an acrylate ester or methacrylate ester containing an isocyanate group or a blocked isocyanate group, (C) diacrylic acid, dimethacrylic acid or a metal salt thereof, and (D) an organic peroxide. In a golf ball having a core formed of the rubber composition and a cover of one or more layers which encases the core, the rubber composition exhibits a spin rate-lowering effect on shots and can thus improve the flight performance of the ball.

A method for forming a golf ball core with a nanofiller masterbatch is disclosed herein. The method includes mixing the nanofiller masterbatch, a graphene masterbatch material with other materials to form a core mixture, wherein the masterbatch preferably comprises 1-80% by weight of nanofillers and 20-99% by weight of a carrier polymer.