Multi-layer golf ball

Abstract

The present invention is directed to an improved multi-layer golf ball comprising a core, an inner cover layer and an outer cover layer. The inner cover layer is comprised of a high acid ionomer or ionomer blend which may or may not include a filler such as zinc-stearate. The outer cover layer is comprised of a soft, very low modulus ionomer or ionomer blend, or a non-ionomeric thermoplastic elastomer such as polyurethane, polyester or polyesteramide. The resulting multi-layered golf ball of the present invention provides for enhanced distance without sacrificing playability or durability when compared to known multi-layer golf balls.

I claim:  
     
         1 . A three piece solid golf ball comprising: 
 a center core, an intermediate layer, and a cover enclosing the core through the intermediate layer;    said center core having a diameter of at least 29 mm (1.1417 inches) and a specific gravity of less than 1.4;    said intermediate layer having a thickness of at least 1 mm (0.03937 inches), a specific gravity of less than 1.2, and a hardness of at least 85 on JIS C (Shore C) scale, the specific gravity of said intermediate layer being lower than the specific gravity of said center core; and    said cover having a thickness of 1 to 3 mm (0.03937 to 0.1182 inches) and being softer than said intermediate layer.    
     
     
         2 . The golf ball of    claim 1    wherein said intermediate layer is formed of a high repulsion ionomer resin base composition.  
     
     
         3 . The golf ball of    claim 1    wherein said center core has a hardness of 45 to 80 on JIS C scale and said cover has a hardness of 50 to 85 on JIS C scale.  
     
     
         4 . The golf ball of    claim 1    wherein said center core is comprised of a polybutadiene base rubber composition.  
     
     
         5 . The golf ball of    claim 1    wherein the diameter of said center core is in the range of 29-37 mm.  
     
     
         6 . The golf ball of    claim 1    wherein a difference in the specific gravity between the center core and the intermediate layer is in the range of 0.1 to 0.5.  
     
     
         7 . The golf ball of    claim 1    wherein the specific gravity of said intermediate layer is in the range of 0.9 to 1.0.  
     
     
         8 . The golf ball of    claim 1    wherein the hardness of said intermediate layer is in the range of 85-100 on JIS C.