In a golf ball having a core and a cover of one or a plurality of layers that encases the core, the core or at least one layer of the cover is formed of a resin composition which contains from 5 to 250 parts by weight of a mechanoluminescent material that receives mechanical energy and luminesces per 100 parts by weight of a base material which is a rubber material or a resin material. This golf ball has an excellent visibility in that, even under dark conditions, the ball impact site can be clearly confirmed visually at the time of impact. Moreover, the ball is able to maintain a good scuff resistance.

In a golf ball having a core and a cover, the core is formed of a rubber composition, has center and surface portions which are unfoamed regions and has an intermediate portion containing a foamed region. The core is produced by charging the rubber composition, which contains a blowing agent, into a first curing mold and curing under given conditions, then removing the molded rubber material in a semi-cured state from the first mold, transferring the semi-cured material to a second curing mold and curing under given conditions. The foamed region of the core deforms by a certain degree at the time of impact, decreasing the radius of gyration of the ball and enabling a lower spin rate to be achieved. The decrease in resilience due to expansion of the molded material can be held to a minimum.

Buoyant dimpled golf ball having CoR ≥0.810, specific gravity <1.00 g/cc, initial velocity ≥250 ft/s, first aerodynamic coefficient magnitude between about 0.25 and about 0.30 and first aerodynamic force angle between about 29 degrees and 34 degrees at Reynolds Number of 230000 and spin ratio of 0.085; and second aerodynamic coefficient magnitude between about 0.26 and about 0.31 and second aerodynamic force angle between about 31 degrees and 36 degrees at Reynolds Number of 180000 and spin ratio of 0.101. Golf ball may additionally have third aerodynamic coefficient magnitude between about 0.27 and about 0.32 and third aerodynamic force angle between about 34 degrees and 39 degrees at Reynolds Number of 133000 and spin ratio of 0.133; and fourth aerodynamic coefficient magnitude between about 0.33 and about 0.38 and fourth aerodynamic force angle between about 38 degrees and 43 degrees at Reynolds Number of 89000 and spin ratio of 0.183.

The invention provides a golf ball that is a one-piece golf ball or a golf ball having a core and a cover of one layer or a plurality of layers, wherein the one-piece golf ball or core is formed of a material molded under heat from a rubber composition containing: (A) a base rubber, (B) an organic peroxide, (C) water, (D) a metal methacrylate and (E) zinc oxide.

The content of component (D) per 100 parts by weight of component (A) is from 30 to 45 parts by weight. The molar ratio (C)/(D) between components (C) and (D) satisfies the formula

0.9<(C)/(D)<1.1.

The core has an initial velocity V.sub.0 of at least 72.0 m/s and up to 75.0 m/s.

A golf ball with improved durability is disclosed herein. The golf ball has a mantle layer comprising a blend of ionomers and methyl methacrylate, butadiene, styrene (MBS) with a weight percentage of MBS ranging from 5 to 15 weight percent of the mantle layer.

In a golf ball having a core and a cover of one or more layer, the core is formed of a material molded under heat from a rubber composition containing (a) a base rubber, (b) water and/or a lower alcohol having a specific molecular weight, (c) an α,β-unsaturated carboxylic acid and/or a metal salt thereof, and (d) an organic peroxide.

The base rubber (a) is a rubber obtained by mixing together (a-1) a polybutadiene and (a-2) an unneutralized ethylene-unsaturated carboxylic acid copolymer, and subsequently neutralizing the copolymer with (a-3) a metal oxide. Component (a-2) has a specific acid content and accounts for a specific portion of the combined amount of components (a-1) and (a-2). The core surface and center have a specific JIS-C hardness difference therebetween.

This ball achieves both a lower spin rate and excellent durability while maintaining a high rebound.

Multi-layer golf balls comprising a single- or dual-layer core, an intermediate layer, and an outer cover layer are disclosed. The intermediate layer is formed from a thermoplastic elastomer composition and has a surface hardness which is greater than the center hardness of the core and less than the outer surface hardness of the core. The outer surface hardness of the outer cover layer is greater than the outer surface hardness of the core.

Golf ball comprising at least one layer that is comprised of an air-cured elastomer composition comprising an elastomer and an organic peroxide curing agent.

Golf balls having a single or dual-layered solid core are provided. In one embodiment, the golf ball has dimensions and properties that do not conform to the rules of the United States Golf Association (USGA). For example, the ball weight; ball size; ball spherical symmetry; ball initial velocity; and/or ball overall distance may fall outside of the USGA standards. The dual-layered core can have an inner core comprising a thermoplastic composition and surrounding outer core comprising a thermoset composition. In another embodiment, the dual-layered core has an inner core comprising a thermoplastic composition and outer core comprising a thermoset composition. The thermoplastic composition preferably comprises an ethylene acid copolymer ionomer and plasticizer. The thermoset composition preferably comprises polybutadiene rubber. The ball further includes a cover of at least one layer.

Golf ball methods and molds for quickly and efficiently eliminating air/gas from within a mold during golf ball manufacture and the improved golf balls resulting therefrom.