Golf ball with ground down medial layer

Abstract

A golf ball includes a core, one or more inlaid portions formed into the core, and a second layer disposed radially outward of both the core and the one or more inlaid portions. The core and the one or more inlaid portions cooperate to define a continuous spherical surface, and the core and the second layer cooperate to surround each of the one or more inlaid portions. The one or more inlaid portions are formed by over-molding the core, and then removing the over-molded material back to at least the outer surface of the core.

1 . A golf ball comprising:
 a core;   one or more inlaid portions formed into the core, wherein the core and the one or more inlaid portions cooperate to define a continuous spherical surface;   a second layer disposed radially outward of both the core and the one or more inlaid portions; wherein the core and the second layer cooperate to surround each of the one or more inlaid portions.   
     
     
         2 . The golf ball of  claim 1 , wherein the core, the one or more inlaid portions, and the second layer are each formed from a different material. 
     
     
         3 . The golf ball of  claim 1 , wherein the one or more inlaid portions define from about 25% to about 70% of the continuous spherical surface. 
     
     
         4 . The golf ball of  claim 1 , wherein the one or more inlaid portions have a hardness value, measured on the Shore D scale, that is less than the hardness value of the core. 
     
     
         5 . The golf ball of  claim 1 , wherein the core includes a plurality of protrusions and one or more recesses; and
 wherein the one or more inlaid portions are disposed within the one or more recesses such that the one or more inlaid portions and the plurality of protrusions cooperate to define the continuous spherical surface.   
     
     
         6 . The golf ball of  claim 5 , wherein the one or more recesses are symmetrically disposed about the core. 
     
     
         7 . The golf ball of  claim 5 , wherein one of the one or more inlaid portions surrounds more than 50 of the plurality of protrusions on the common spherical surface. 
     
     
         8 . The golf ball of  claim 5 , wherein there are more than 50 of at least one of the plurality of protrusions and the one or more recesses. 
     
     
         9 . The golf ball of  claim 1 , wherein the second layer contacts the continuous spherical surface across the entire spherical surface. 
     
     
         10 . The golf ball of  claim 1 , further comprising a cover surrounding the second layer, wherein the cover includes a plurality of dimples formed into a radially outward surface. 
     
     
         11 . The golf ball of  claim 1 , wherein the core is formed from a thermoplastic polymer that includes an ionomeric material, a highly neutralized ionomer resin, a polyamide resin, a polyester resin, or a polyurethane resin; wherein the one or more inlaid portions are formed from an ethylene copolymers or an ionomeric material; and wherein the second layer is formed from a thermoset polymer that includes a polyurethane elastomer, a polyamide elastomer, a polyurea elastomer, a diene-containing polymer, a crosslinked metallocene catalyzed polyolefin, or a silicone. 
     
     
         12 . The golf ball of  claim 1 , wherein the one or more inlaid portions have a hardness value, measured on the Shore D scale, that is greater than the hardness value of the core. 
     
     
         13 . A method of making a multi-layer golf ball having one or more inlaid portions formed into a material layer, the method comprising:
 molding a substantially spherical core from a first material, wherein the core includes a surface that extends to a first, maximal, radial distance and wherein the surface defines a one or more recessed areas that extend to a second, minimal, radial distance;   over-molding the core with a second material such that the second material fills the one or more recessed areas and extends radially outward to a third radial distance that is greater than the first radial distance, wherein the core and the over-molded second material form a first intermediate ball;   removing material from the first intermediate ball to form a second intermediate ball;
 wherein the second intermediate ball has a continuous spherical surface at a fourth radial distance; 
 wherein the first material and the second material cooperate to define the continuous spherical surface; 
 wherein the fourth radial distance is less than or equal to the first radial distance and greater than the second radial distance; and 
   over-molding the second intermediate ball with a third material.   
     
     
         14 . The method of  claim 13 , wherein removing material from the first intermediate ball occurs through grinding. 
     
     
         15 . The method of  claim 13 , wherein the second material forms from about 25% to about 70% of the continuous spherical surface. 
     
     
         16 . The method of  claim 13 , wherein the difference between the first radial distance and the third radial distance is from about 1 mm to about 3 mm. 
     
     
         17 . The method of  claim 13 , wherein the difference between the second radial distance and the fourth radial distance is from about 1 mm to about 3 mm. 
     
     
         18 . The method of  claim 13 , wherein the one or more recessed areas are symmetrically disposed about the core. 
     
     
         19 . The method of  claim 13 , further comprising over-molding the third material with a fourth material to form a cover; and
 wherein the cover includes a plurality of dimples disposed on a radially outer surface.   
     
     
         20 . The method of  claim 13 , wherein each of molding a substantially spherical core and over-molding the core with a second material respectively includes injection molding.