Golf Ball With Resin Inner Core

Abstract

A high performance golf ball includes a resin inner core, a rubber outer core, and a cover. The resin inner core is made of highly neutralized polymer, and may include a blend of different highly neutralized polymers. The cover is a two layer cover, with a hard inner cover and a thermoplastic polyurethane outer cover. The ball as a whole has properties to maximize performance and aesthetic properties, such as feel and sound.

What is claimed is: 
     
         1 . A golf ball comprising:
 an inner core layer comprising a highly neutralized polymer;   the inner core layer having an inner core layer compression between 3.5 mm and 4.1 mm when measured with an initial load of 10 kg and a final load of 130 kg;   an outer core layer enclosing the inner core layer, wherein the outer core layer comprises polybutadiene rubber;   the outer core layer having a thickness of at least 4.8 mm;   the outer core layer having an outer core layer compression between 2.7 mm and 3.3 mm when measured with an initial load of 10 kg and a final load of 130 kg;   an inner cover layer enclosing the outer core layer;   an outer cover layer enclosing the inner cover layer, the outer cover layer comprising thermoplastic polyurethane,   wherein a ball coefficient of restitution is 0.8 or less, and   wherein a ratio of the inner core layer compression to the outer core layer compression is between 1.1 and 1.4.   
     
     
         2 . The golf ball of  claim 1 , wherein the inner core layer has a diameter between 20 mm and 28 mm. 
     
     
         3 . The golf ball of  claim 1 , wherein the inner core layer comprises a blend of two different highly neutralized polymers. 
     
     
         4 . The golf ball of  claim 1 , wherein the inner core layer consists essentially of two different highly neutralized polymers and an additional material. 
     
     
         5 . The golf ball of  claim 4 , wherein the additional material comprises at least one of a filler, an additive, and a melt flow modifier. 
     
     
         6 . The golf ball of  claim 1 , wherein the inner core layer is adhered to the outer core layer with an adhesive. 
     
     
         7 . The golf ball of  claim 1 , wherein the inner cover layer is thermoplastic. 
     
     
         8 . The golf ball of  claim 7 , wherein the inner cover layer is a urethane. 
     
     
         9 . The golf ball of  claim 7 , wherein the inner cover layer is an ionomer resin. 
     
     
         10 . The golf ball of  claim 7 , wherein the inner cover layer is selected from the group consisting of: a highly neutralized polymer composition, a polyamide resin, a polyester resin, and a polyurethane resin.