An object of the present invention is to provide a golf ball striking a good balance between flight distance on driver shots and spin rate on approach shots, and excellent in stain resistance and shot feeling. The present invention provides a golf ball comprising a paint film, wherein a base resin of the paint film contains a polyurethane obtained by a reaction between a polyisocyanate composition and a polyol composition containing a urethane polyol having a polyether diol with a number average molecular weight in a range from 800 to 3,000 as a constituent component, and the following requirements are satisfied:
Mp≦200×X−75
Mp≦100
Minm−Moum>40
Moum−Mc<5
Tinm≧Toum>Tc>Tp
(Tinm×Minm)/(Toum×Moum)>2.0
(Toum×Moum)/(Tc×Mc)<3.0
(Tc×Mc)/(Tp×Mp)>10.0
[where Mp, Minm, Moum, and Mc represent a 10% elastic modulus (kgf/cm.sup.2) of the paint film, inner intermediate layer, outer intermediate layer and cover, respectively; Tp, Tinm, Toum, and Tc represent a thicknesses (mm) of the paint film, inner intermediate layer, outer intermediate layer and cover, respectively; and X represents a molar ratio (NCO/OH) of a NCO group in the polyisocyanate composition to a OH group in the polyol composition.].

A golf ball is provided that achieves a satisfactory distance on full shots with an iron, is superior in the short game, and has a good feel at impact and a good durability. The golf ball has a core formed of a rubber composition as one or more layer, an envelope layer formed of a resin material as one or more layer, an intermediate layer formed of a resin material as one layer, and a cover formed of a resin material as one layer having a thickness of not more than 1.0 mm. The layers of the ball have Shore C hardnesses at the respective surfaces thereof which together satisfy certain conditions, and the core and the ball have respective deflections which satisfy certain other conditions.

A golf ball is provided that achieves a satisfactory distance on full shots with a driver and an iron, is superior in the short game, and has a good feel at impact and a good durability. The golf ball has a core formed of a rubber composition as one or more layer, an inner envelope layer formed of a resin material as one or more layer, an outer envelope layer and intermediate layer which are each formed of a resin material as one layer, and a cover formed of a resin material as one layer having a thickness of not more than 1.0 mm. The inner envelope layer-encased sphere, outer envelope layer-encased sphere, intermediate layer-encased sphere and ball have Shore C hardnesses at the respective surfaces thereof which together satisfy certain conditions, and the ball has at least a given deflection under specific loading conditions.

A golf ball 2 includes a spherical core 4, a mid layer 6, and a cover 8. The core 4 is obtained by crosslinking a rubber composition. The difference between: a hardness H(5.0) at a point which is located at a distance of 5 mm from the central point of the core 4; and a hardness Ho at the central point is 6.0 or greater. The difference between: a hardness H(12.5) at a point which is located at a distance of 12.5 mm from the central point; and the hardness H(5.0) is 4.0 or less. The difference between a hardness Hs at the surface of the core 4 and the hardness H(12.5) is 10.0 or greater. The difference between the hardness Hs and the hardness Ho is 22.0 or greater. There is no zone in which a hardness decreases from the central point to the surface. A Shore D hardness H3 of the cover is greater than a Shore D hardness H2 of the mid layer.

A golf ball with embedded electronics to allow proximity to be tracked and to monitor golfer performance is disclosed. The golf ball comprises a processor connected to an accelerometer, communications circuitry, a spin detector, and memory, wherein the processor stores accelerometer data from the accelerometer and rotation data regarding rotation of the spin detector in the memory. The processor converts the data regarding the rotation of the spin detector into a rotation speed and a rotation direction, said rotation speed determined by a frequency of the data, and said rotation direction determined by a magnitude of the data. The communications circuitry is configured to communicate the accelerometer data, the rotation direction, and the rotation speed to a central interrogator for analysis of a golfer's performance.

A golf ball resin composition contains a base resin for which, in dynamic viscoelasticity measurement, the storage modulus of the base resin measured at 23° C., 15 Hz and 1.0% strain, and tan δ determined under the same conditions, satisfy specific values; and for which the storage modulus of the base resin measured at 23° C., 15 Hz and 10% strain, and tan δ determined under the same conditions, satisfy specific values. By using this resin composition as a golf ball cover material, the force delivered to the ball while the ball and the clubface are in contact from impact to follow-through is more easily felt, facilitating distance control of the ball. Controllability with a short iron such as a sand wedge around the green is also excellent.

Golf ball having at least three layers comprising ionomeric and/or HNP compositions, wherein for each two adjacent layers, a relationship is established between a ratio of the volumes of the two adjacent layers and a ratio of the percent neutralizations of those two layers such that the volumes and % neutralizations of all layers are interrelated and interdependent to produce unique and desirable playing characteristics. In one embodiment, a golf ball of the invention has T layers, wherein T≧3 and each of T layers has a different volume “V” and comprises an ionomeric and/or HNP composition having a different % neutralization “N”. Furthermore, each of n inner layers of the T layers (n<T) has an adjacent surrounding layer n+1 such that a volume V.sub.n and a % neutralization N.sub.n of each inner layer and a volume V.sub.(n+1) and % neutralization N.sub.(n+1) of each adjacent surrounding layer n+1 satisfy the relationship (V.sub.n−V.sub.(n+1))/N.sub.n≧(N.sub.n−N.sub.(n+1))/N.sub.(n+1).

Golf ball having at least three layers comprising an ionomeric and/or HNP composition, wherein for each two adjacent layers, a relationship is established between a ratio of the volumes of the two adjacent layers and a ratio of the percent neutralizations of those two layers such that the volumes and % neutralizations of all layers are interrelated and interdependent to produce unique and desirable playing characteristics. In one embodiment, each of T layers, wherein T≧3, has a different volume “V” and comprises an ionomeric/HNP composition having a different % neutralization “N”; and wherein each of n inner layers of the T layers (n<T) has an adjacent surrounding layer n+1 such that a volume V.sub.n and a % neutralization N.sub.n of each inner layer and a volume V.sub.(n+1) and % neutralization N.sub.(n+1) of each adjacent surrounding layer n+1 satisfy the relationship (V.sub.(n+1)−V.sub.n)/V.sub.(n+1)≦(N.sub.(n+1)−N.sub.n)/N.sub.n.

A golf ball includes a core and a three-layer cover disposed adjacent the core. The three-layer cover includes an inner cover, an intermediate cover, and an outer cover. The inner cover includes a non-ionomeric E/Y copolymer where E is an olefin and Y is a carboxylic acid. The inner cover has a hardness of about 45 to 68 Shore D. The outer cover includes a castable thermoset polyurethane and has a hardness of about 40 to 62 Shore D. The intermediate cover layer, disposed between the inner and outer cover layers, is formed from a polyamide composition, where the polyamide composition includes a transparent polyamide having a light transmission of about 50% or greater.

Golf ball having at least three layers comprising ionomeric and/or HNP compositions, wherein for each two adjacent layers, a relationship is established between a ratio of the volumes of the two adjacent layers and a ratio of the percent neutralizations of those two layers such that the volumes and % neutralizations of all layers are interrelated and interdependent to produce unique and desirable playing characteristics. In one embodiment, a golf ball of the invention has T layers, wherein T≧3 and each of T layers has a different volume “V” and comprises an ionomeric and/or HNP composition having a different % neutralization “N”; and wherein each of n inner layers of the T layers (n<T) has an adjacent surrounding layer n+1 such that a volume V.sub.n and a % neutralization N.sub.n of each inner layer and a volume V.sub.(n+1) and % neutralization N.sub.(n+1) of each adjacent surrounding layer n+1 satisfy the relationship (V.sub.(n+1)−V.sub.n)/V.sub.(n+1)≦(N.sub.n−N.sub.(n+1))/N.sub.(n+1).