Multi-layer cover polyurethane golf ball

#This invention relates generally to golf balls, and more specifically, to a golf ball having a cover comprising three or more layers.

#The majority of golf balls commercially available today can be grouped into two general classes: solid and wound. Solid golf balls include one-piece, two-piece, and multi-layer golf balls. One-piece golf balls are inexpensive and easy to construct, but have limited playing characteristics and their use is usually confined to the driving range. Two-piece balls are generally constructed with a polybutadiene solid core and a cover and are typically the most popular with recreational golfers because they are very durable and provide good distance. These balls are also relatively inexpensive and easy to manufacture, but are regarded by top players as having limited playing characteristics. Multi-layer golf balls are comprised of a solid core and a cover, either of which may be formed of one or more layers. These balls are regarded as having an extended range of playing characteristics, but are more expensive and difficult to manufacture than are one- and two-piece golf balls.

#Wound golf balls, which typically include a fluid-filled center surrounded by tensioned elastomeric material and a cover, are preferred by many players due to their spin and “feel” characteristics but are more difficult and expensive to manufacture than are most solid golf balls. Manufacturers are constantly striving, therefore, to produce a solid ball that retains the beneficial characteristics of a solid ball while concurrently exhibiting the beneficial characteristics of a wound ball.

#FIG. 1 is one embodiment of the golf ball of the present invention having a solid core and an inner, intermediate, and outer cover layer;

#FIG. 2 is a second embodiment of the golf ball of the present invention having a core formed of a solid center and an outer core layer; and an inner, intermediate, and outer cover layer; and

#FIG. 3 is a third embodiment of the present invention having a liquid core formed of a liquid center and an outer core layer; and a cover formed of an inner, intermediate, and outer cover layer.

#Referring to FIG. 1, a golf ball 10 of the present invention includes a core 12 and a cover comprising an outer cover 14 and at least two inner cover layers, such as inner cover layer 16 and intermediate cover layer 18. The golf ball cores of the present invention may be formed with a variety of constructions. For example, a golf ball 20 may also comprise a core comprising a plurality of layers, such as a center 22 and an outer core layer 24, and a cover comprising an outer cover layer 26, an inner cover layer 28, and an intermediate cover layer 30, as seen in FIG. 2. Referring to FIG. 3, the golf ball 40 may also comprise a core 44 comprising a solid, liquid, foam, gel, or hollow center 42, and a cover comprising an outer cover layer 46, an inner cover layer 48, and an intermediate cover layer 50. Any one of the inner cover layer 48 or the intermediate cover layer 50 may also comprise a tensioned elastomeric material. In a preferred embodiment, the core is a solid core.

#Materials for solid cores include compositions having a base rubber, a filler, an initiator agent, and a crosslinking agent. The base rubber typically includes natural or synthetic rubber, such as polybutadiene rubber. A preferred base rubber is 1,4-polybutadiene having a cis-structure of at least 40%. Most preferably, however, the solid core is formed of a resilient rubber-based component comprising a high-Mooney-viscosity rubber and a crosslinking agent.

#Another suitable rubber from which to form cores of the present invention is trans-polybutadiene. This polybutadiene isomer is formed by converting the cis-isomer of the polybutadiene to the trans-isomer during a molding cycle. Various combinations of polymers, cis-to-trans catalysts, fillers, crosslinkers, and a source of free radicals, may be used. A variety of methods and materials for performing the cis-to-trans conversion have been disclosed in U.S. Pat. No. 6,162,135 and U.S. application Ser. No. 09/461,736, filed Dec. 16, 1999; Ser. No. 09/458,676, filed Dec. 10, 1999; and Ser. No. 09/461,421, filed Dec. 16, 1999, each of which are incorporated herein, in their entirety, by reference.