In a golf ball having a core and a cover, the cover is formed primarily of polyurethane, the ball has a diameter of at least 42.8 mm and a weight of not more than 44.9 g and, in an impact test carried out by hitting the ball with a driver at a head speed of 40 m/s, the sum t1+t2 of the time t1 required from initial contact by the driver with the ball for deformation of the ball to reach a maximum and the time t2 required from the state of maximum ball deformation for the ball and driver to separate is not more than 660 μsec. This golf ball makes it possible for golfers who have a high head speed and ordinary golfers who do not to compete without relying excessively on superiority in terms of distance.

A golf ball according to the present invention comprises: a core having a diameter of 37-39 mm and a first density; a mantle which surrounds the core, includes amorphous alloy powder, and has a thickness of 0.8-1.2 mm and a second density; and a cover which surrounds the mantle and has a thickness of 1-1.4 mm and a third density.

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 distance golf ball endowed with a good flight performance when struck with a driver or an iron by an ordinary amateur golfer, a good durability to repeated impact and a soft feel. The ball is a multi-piece solid golf ball having a core, an intermediate layer and a cover, wherein the core is formed as one or more layer of a rubber composition, the intermediate layer is formed primarily of an ionomer resin, the intermediate layer and the cover are both single layers, each containing an inorganic granular filler, and the ball satisfies the following conditions: surface hardness of ball > surface hardness of sphere consisting of core encased by intermediate layer (intermediate layer-encased sphere), Shore D hardness at surface of ball - Shore D hardness at center of core ≥ 37, specific gravity of cover > specific gravity of intermediate layer.

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),

14≤(Atti compression of core)≤38,

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

600≤(Shore C hardness at surface of intermediate layer-encased sphere)×(specific gravity of intermediate layer material)×[volume (cm.sup.3) of intermediate layer material].

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 primarily skilled amateur golfers who handle iron shots skillfully.

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.

A golf ball comprising a core composed of a fully neutralized polymer material is disclosed herein. The golf ball also preferably has multiple mantle layers and a cover.

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.

Buoyant dimpled golf ball having CoR0.810, 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.