A golf ball is provided that includes at least one porous resin layer formed of a resin composition containing a polymeric material and a leachable water-soluble polymer. In a method for producing the golf ball, a resin composition containing the polymeric material and the water-soluble polymer is molded to form a solid molded body, following which the water-soluble polymer is partially leached out and removed. The golf ball has an improved ball controllability on approach shots and an improved feel at impact, maintains a good scuff resistance and has a good moldability.

An object of the present invention is to provide a golf ball having excellent resilience performance. The present invention provides a golf ball comprising a constituent member, wherein at least a part of the constituent member is formed from a rubber composition containing (a) a base rubber, (b) a co-crosslinking agent, (c) a crosslinking initiator, and (d) an organic sulfur compound, wherein (d) the organic sulfur compound contains at least one member selected from the group consisting of a thiophenol having a halogenated sulfanyl group, a metal salt of a thiophenol having a halogenated sulfanyl group, and a diphenyl disulfide having a halogenated sulfanyl group.

In a golf ball having a core of one or more layer, an intermediate layer and a cover, the cover consists of an inner cover layer and an outer cover layer, the inner cover layer and the outer cover layer being made of materials having hardnesses on the Shore D hardness scale of, respectively, from 20 to 40 and from 35 to 55, and the inner and outer cover layers having a combined thickness of from 0.6 to 1.2 mm. Also, letting (A) and (B) be the rebound resiliences (%) of, respectively, the inner cover layer material and the outer cover layer material based on JIS-K 6255, the ball satisfies the condition 0%<(A)−(B)<18%. This ball exhibits a higher spin rate on approach shots and a good feel without lowering the distance performance on shots with a driver (W #1).

A foam composition that includes a polymer material such as polyurethane or polyurea and a leachable water-soluble fine powder is provided. This composition can be used in a relatively simple process to obtain a foam body (porous body) that is uniform only at the surface or uniform throughout. The foam body can be suitably used as a golf ball member in golf balls required to have good controllability on approach shots. Also provided is a method for producing a foam member, which method includes the steps of molding the foam composition to obtain a solid molded body, and then leaching out and removing the water-soluble fine powder so as to obtain a foam-molded body.

The present invention provides methods for producing molded golf balls and the resultant balls. The methods of this invention involve producing foamed polyurethane covers and these methods help reduce dimple distortions and other surface imperfections. These golf balls contain an inner core and outer foamed polyurethane cover. One or more intermediate layers can be disposed between the core and cover. In one embodiment, a castable liquid polyurethane composition containing a foaming agent is dispensed into mold cavities, which are then pressed together to form a foam cover for the ball.

In a golf ball having a rubber core of at least one layer and a cover of at least one layer that encases the core, at least one layer of the cover is formed of a resin composition which includes (A) a polyurethane or a polyurea, (B) an alkyl methacrylate/alkyl acrylate copolymer, and (C) a fatty acid amide. The golf ball has an excellent mold releasability during molding of the cover while retaining a good spin rate on approach shots, scuff resistance and paint film durability.

The present invention provides methods for producing molded golf balls and the resultant balls. The methods of this invention involve producing foamed polyurethane covers and these methods help reduce dimple distortions and other surface imperfections. These golf balls contain an inner core and outer foamed polyurethane cover. One or more intermediate layers can be disposed between the core and cover. In one embodiment, a castable liquid polyurethane composition containing a foaming agent is dispensed into mold cavities, which are then pressed together to form a foam cover for the ball.

The present invention provides methods for producing molded golf balls and the resultant balls. The methods of this invention involve producing foamed polyurethane covers and these methods help reduce dimple distortions and other surface imperfections. These golf balls contain an inner core and outer foamed polyurethane cover. One or more intermediate layers can be disposed between the core and cover. In one embodiment, a castable liquid polyurethane composition containing a foaming agent is dispensed into mold cavities, which are then pressed together to form a foam cover for the ball.

In a golf ball having a rubber core of at least one layer and an inner cover layer and outer cover layer which encase the core, the inner cover layer is formed of a resin composition that includes (A) a polyurethane or polyurea and (B) a thermoplastic polyester elastomer, which resin composition has a Shore D hardness of 52 or less and a rebound resilience of at least 50%, and the outer cover layer is formed of a resin composition which includes a polyurethane or polyurea of the same type as component (A) or of a different type. This ball has an improved rebound, an optimal spin rate on approach shots and thus a good controllability, and an excellent durability.

A resin composition for golf balls is made of (A) polyurethane or polyurea and (B) a styrene resin material, component (B) being included in an amount of 0.5 to 50 parts by weight per 100 parts by weight of component (A). In a golf ball having a core and a cover of one or more layer encasing the core, at least one cover layer is formed of this resin composition. The resin composition is especially useful as a golf ball cover material because the ball does not fly too far and is easier to control on approach shots, yet does not sacrifice distance on shots with a driver.