In a golf ball having a core and a cover with a plurality of dimples on the surface, the cover is formed primarily of polyurethane, the dimples have a specific volume occupancy ratio and the ball has a diameter of at least 42.8 mm. 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 660 sec 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 golf ball includes a core, an intermediate layer, and a cover, in which the core is formed of a rubber composition into a single layer or a plurality of layers, the intermediate layer and the cover are both formed of a single-layer resin composition, and a relationship between an initial velocity of the core, an initial velocity of a sphere (intermediate layer-encased sphere) in which the core is encased with the intermediate layer, and an initial velocity of a sphere (ball) in which the intermediate layer-encased sphere is encased with the cover satisfies the following two conditions:

(initial velocity of ball)<(initial velocity of intermediate layer-encased sphere)

0.60?(initial velocity of intermediate layer-encased sphere)?(initial velocity of core)?1.00 (m/s). and the specific deflection is 3.00 mm or less, and a specific gravity of the intermediate layer is 1.05 or more.

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.

A golf ball with a mantle layer comprising an ionomer material and a graphene material in an amount ranging from 0.1 to 5.0 weight percent of the mantle layer is disclosed herein. The golf ball may multiple layers. A preferred embodiment of a golf ball comprises a core, a mantle layer and a cover.

A golf ball with a core comprising polybutadiene and graphene, and a soft cover is disclosed herein. The golf ball has a dual core with an outer core comprising polybutadiene and graphene. The soft cover is preferably composed of a highly neutralized polymer, a first ionomer, a second ionomer, and a paraloid impact modifier.

Multi-piece golf balls having a multi-layered solid core and multi-layered cover are provided.

A golf ball for amateur golfers is endowed with both an excellent flight when hit by golfers whose head speed is not very high and a soft yet good feel at impact. The ball has a core, an envelope layer, an intermediate layer and a cover. The core is formed primarily of a base rubber and the intermediate layer is formed so as to be thicker than the envelope layer and the cover. The respective surface hardnesses of the core, envelope layer-encased sphere, intermediate layer-encased sphere and ball satisfy a specific relationship. The core hardness profile is designed such that the surface areas A to F calculated from hardness differences between positions located at specific distances in the core and differences between the specific distances satisfy a specific formula.

A golf ball including a core; an inner cover layer formed from a thermoplastic composition and having a thickness of about 0.005 inches to 0.40 inches and a surface hardness of about 60 Shore D or greater; and an outer cover layer formed from a thermoset material and having a thickness of about 0.01 inches to 0.05 inches and a surface hardness of about 60 Shore D or less. The thermoplastic composition has a first melt flow index at 280 C. under a 10-kg load of less than about 35 g/10 min and a second melt flow index at 265 C. under a 5-kg load of less than about 10 g/10 min.

Multi-piece golf balls having a multi-layered solid core and multi-layered cover are provided.

A golf ball includes a core, a mantle and a cover layer. The core includes polybutadiene and has a diameter of less than 1.45 inches. The core has a deflection of at least 0.220 inches under an applied static load of 200 pounds. The mantle includes a copolymer of ethylene and carboxylic acid. The carboxylic acid contains a plurality of acid groups wherein 40 to 100 percent of the acid groups of the carboxylic acid are neutralized with a metal ion. The cover layer includes a polyurethane material and has a Shore C hardness of greater than 80.