Multi-piece solid golf ball

Abstract

The invention provides a distance golf ball endowed with a good flight performance when struck with a driver or an iron by an ordinary amateur golfer, a good durability to repeated impact and a soft feel. The ball is a multi-piece solid golf ball having a core, an intermediate layer and a cover, wherein the core is formed as one or more layer of a rubber composition, the intermediate layer is formed primarily of an ionomer resin, the intermediate layer and the cover are both single layers, each containing an inorganic granular filler, and the ball satisfies the following conditions: surface hardness of ball > surface hardness of sphere consisting of core encased by intermediate layer (intermediate layer-encased sphere), Shore D hardness at surface of ball - Shore D hardness at center of core ≥ 37, specific gravity of cover > specific gravity of intermediate layer.

1 . A multi-piece solid golf ball comprising a core, an intermediate layer and a cover, wherein the core is formed as one or more layer of a rubber composition, the intermediate layer is formed primarily of an ionomer resin, the intermediate layer and the cover are both single layers, each containing an inorganic granular filler, and the ball satisfies the following conditions:
 surface hardness of ball > surface hardness of sphere consisting of core encased by intermediate layer (intermediate layer-encased sphere),   Shore D hardness at surface of ball - Shore D hardness at center of core ≥ 37,   specific gravity of cover > specific gravity of intermediate layer.   
     
     
         2 . The golf ball of  claim 1 , wherein the cover is composed primarily of an ionomer resin and the intermediate layer is composed primarily of a highly neutralized ionomer resin composition. 
     
     
         3 . The golf ball of  claim 1 , wherein the Shore D hardness at the surface of the ball is 65 or more. 
     
     
         4 . The golf ball of  claim 1 , wherein the specific gravity of the cover is 1.10 or more and the specific gravity of the intermediate layer is 1.05 or more. 
     
     
         5 . The golf ball of  claim 1 , wherein the core has a center hardness Cc and a surface hardness Cs on the Shore C hardness scale such that the value Cs - Cc obtained by subtracting the core center hardness Cc from the core surface hardness Cs is 12 or more. 
     
     
         6 . The golf ball of  claim 1 , wherein the ball has a core surface hardness Cs, a core center hardness Cc and a hardness Cm at a midpoint between the core surface and the core center, all on the Shore C hardness scale, which together satisfy the following condition:
                 Cs - Cm         /         Cm - Cc       ≥   1.2.               .   
     
     
         7 . A multi-piece solid golf ball comprising a core, an intermediate layer and a cover, wherein the core is formed as one or more layer of a rubber composition, the intermediate layer is formed primarily of an ionomer resin, and the ball satisfies the following conditions:
 surface hardness of ball > surface hardness of sphere consisting of core encased by intermediate layer (intermediate layer-encased sphere),   Shore D hardness at surface of ball - Shore D hardness at center of core ≥ 37,   specific gravity of cover > specific gravity of intermediate layer, with the provisos that specific gravity of intermediate layer ≥ 1.05 and specific gravity of cover ≥ 1.10.   
     
     
         8 . The golf ball of  claim 7 , wherein the cover is composed primarily of an ionomer resin and the intermediate layer is composed primarily of a highly neutralized ionomer resin composition. 
     
     
         9 . The golf ball of  claim 7 , wherein the intermediate layer and the cover each contain an inorganic granular filler. 
     
     
         10 . The golf ball of  claim 7 , wherein the Shore D hardness at the surface of the ball is 65 or more. 
     
     
         11 . The golf ball of  claim 7 , wherein the core has a center hardness Cc and a surface hardness Cs on the Shore C hardness scale such that the value Cs - Cc obtained by subtracting the core center hardness Cc from the core surface hardness Cs is 12 or more. 
     
     
         12 . The golf ball of  claim 7 , wherein the ball has a core surface hardness Cs, a core center hardness Cc and a hardness Cm at a midpoint between the core surface and the core center, all on the Shore C hardness scale, which together satisfy the following condition:
                 Cs - Cm         /         Cm - Cc       ≥   1.2.               .