In a golf ball having a core, an envelope layer, an intermediate layer and a cover, the core, the envelope layer-encased sphere obtained by encasing the core with the envelope layer, the intermediate layer-encased sphere obtained by encasing the envelope layer-encased sphere with the intermediate layer and the ball obtained by encasing the intermediate layer-encased sphere with the cover have respective deflections when compressed under a final load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf) which satisfy specific conditions. This ball achieves a good distance on shots with a utility club and with irons, is receptive to spin in the short game and has a soft feel at impact on all shots, making it useful to amateur golfers.

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 43.0 mm 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 650 μsec or less. 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.

In a golf ball having a core and a cover, the cover is formed primarily of polyurethane, the ball has a weight of 44.8 g or less 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 650 μsec or less. 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.

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.

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 specific conditions, the core and the ball have respective deflections which satisfy certain conditions and the core has a specific internal hardness profile.

A golf ball a core, one or more intermediate layers, and one or more cover layers. The core may comprise an inner portion and an outer portion. One or more layers of the golf ball may be formed by the application of ultrasonic welding on two half shells to form. One or more of the layers may be formed by a number of different chemical compositions, and may have varying thicknesses, hardnesses, coefficients of restitution, and PGA compression. The golf ball itself may have varying coefficient of restitution and PGA compression, depending on the layers.

A golf ball comprising a core comprising an inner core center and an outer core layer disposed over the inner core center. The inner core center has a deflection of greater than 0.210 inch under a load of 100 kilograms, and the entire the core has a deflection ranging from 0.130 inch to 0.105 inch under a load of 100 kilograms. A mantle layer is disposed over the core and a cover is disposed over the mantle.

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 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.