Golf ball

Abstract

A golf ball is provided with a compression deformation of 2 mm and 4 mm and has a core made from a thermoplastic material, an intermediate layer made from a thermoset material, and at least one cover layer. The COR of the core falls between 0.78 and 0.89 and is higher than that of the whole golf ball. In this way, the golf ball has long flight distance and good hitting feel to fit both of the amateur golfers, whose swing speed is lower, and the low-handicap or professional golfers, whose swing speed is higher.

1 . A golf ball having a compression deformation of 2 mm to 4 mm, comprising:
 a core made from a thermoplastic material, having its coefficient of restitution (COR) falling between approximately 0.78 and 0.89 and higher than that of said golf ball;   an intermediate layer enclosing said core and made from a thermoset material; and   a cover layer enclosing said intermediate layer.   
     
     
         2 . The golf ball as defined in  claim 1 , wherein the compression deformation falls between 2.7 mm and 3.7 mm. 
     
     
         3 . The golf ball as defined in  claim 1 , wherein the golf ball has a COR falling between approximately 0.78 and 0.83. 
     
     
         4 . The golf ball as defined in  claim 1 , wherein the COR of said core falls between approximately 0.79 and 0.89. 
     
     
         5 . The golf ball as defined in  claim 1 , wherein said core has a diameter of 19 mm to 37 mm. 
     
     
         6 . The golf ball as defined in  claim 1 , wherein the COR of said core is higher by at least 0.01 than that of said golf ball. 
     
     
         7 . The golf ball as defined in  claim 1 , wherein said thermoplastic material is selected from a group consisting of ionomer resin, polyamide resin, polyester resin, and polyurethane resin. 
     
     
         8 . The golf ball as defined in  claim 1 , wherein said core is provided with a specific gravity of between 0.9 and 1.2. 
     
     
         9 . The golf ball as defined in  claim 1 , wherein said golf ball is provided with a specific gravity of between 0.97 and 1.2. 
     
     
         10 . The golf ball as defined in  claim 1 , wherein said intermediate layer comprises an external surface having a Shore D hardness of 40 to 60; said cover layer comprises an external surface having a Shore D hardness of 40 to 75. 
     
     
         11 . A golf ball whose moment of inertia (MOI) is at least 79 g·cm 2 , comprising:
 a core made from a thermoplastic material, having its COR of between approximately 0.78 and 0.89 and higher than that of said golf ball;   an intermediate layer enclosing said core and made from a thermoset material; and   a cover layer enclosing said intermediate layer.   
     
     
         12 . The golf ball as defined in  claim 11 , wherein the MOI falls within 83 to 86 g·cm 2 . 
     
     
         13 . The golf ball as defined in  claim 11 , wherein the golf ball has a compression deformation of 2 mm to 4 mm. 
     
     
         14 . The golf ball as defined in  claim 13 , wherein the compression deformation is between 2.7 mm and 3.7 mm. 
     
     
         15 . The golf ball as defined in  claim 11 , wherein the COR of said core falls between 0.79 and 0.89. 
     
     
         16 . The golf ball as defined in  claim 11 , wherein said core is provided with a diameter of 19 mm to 37 mm. 
     
     
         17 . The golf ball as defined in  claim 11 , wherein the COR of said core is higher by at least 0.01 than that of said golf ball. 
     
     
         18 . The golf ball as defined in  claim 11 , wherein said core is provided with a specific gravity between 0.9 and 1.2. 
     
     
         19 . The golf ball as defined in  claim 11 , wherein said golf ball is provided with a specific gravity between 0.97 and 1.2. 
     
     
         20 . The golf ball as defined in  claim 11 , wherein said intermediate layer comprises an external surface having a Shore D hardness of 40 to 60; said cover layer comprises an external surface having a Shore D hardness of 40 to 75.