Golf ball with dual cover

#The present invention generally relates to golf balls, and, more particularly, to a golf ball having a solid core and a multi-layer ionomeric cover.

#Golf balls traditionally have been categorized in three different groups, namely, as one-piece, two-piece and three-piece balls. Conventional two-piece golf balls include a solid resilient core having a cover of a different type of material molded thereon. Three-piece golf balls traditionally have included a liquid or solid center, elastomeric winding around the center, and a molded cover. Solid cores of both two and three-piece balls often are made of polybutadiene and the molded covers generally are made of natural balata, synthetic balata, or ionomeric resins.

#Ionomeric resins are polymers containing interchain ionic bonding. As a result of their toughness, durability and flight characteristics, various ionomeric resins sold by E. I. DuPont de Nemours & Company under the trademark “Surlyne®” and by the Exxon Corporation (see U.S. Pat. No. 4,911,451) under the trademark “Escor®” and the trade name “lotek,” have become the materials of choice for the construction of golf ball covers over the traditional “balata” (transpolyisoprene, natural or synthetic) rubbers. The softer balata covers, although exhibiting enhanced playability properties, lack the durability (cut and abrasion resistance, fatigue endurance, etc.) properties required for repetitive play.

#FIG. 1 shows a cross-sectional view of a golf ball according to a preferred embodiment of the invention.

#FIG. 2 shows a diametrical cross-sectional view of the golf ball shown in FIG. 1.

#The preferred embodiment golf ball according to the present invention has a central core and a cover which includes at least two ionomeric layers. The inner cover layer is softer than the outer cover layer. This type of construction results in a golf ball having a soft compression while maintaining a good COR and a moderate spin rate.

#The invention in a preferred form is a golf ball comprising a core, an inner cover layer comprising an ionomer and an outer cover layer comprising an ionomer. The inner cover layer has a Shore D hardness of about 56-65. The outer cover layer has a Shore D hardness which is greater than the Shore D hardness of the inner cover layer and is about 65-70. The sum of the thickness of the inner cover layer and the thickness of the outer cover layer is at least 0.090 inches (0.23 mm).

#The golf ball core typically is selected from the group consisting of non-wound cores containing liquid, gel or solid and wound cores. Preferably, the core is solid.