Golf ball material, golf ball and method for preparing golf ball material

Abstract

A golf ball material composed of (A) an olefin-containing thermoplastic polymer having an acid content of at least 0.5 wt % but less than 5.0 wt %, (B) a resin composition which includes one or more selected from the group consisting of diene polymers, thermoplastic polymers and thermoset polymers, and (C) an oxygen-containing inorganic metal compound has a good thermal stability, flow and processability, making it suitable for injection molding. The golf ball material is ideal for the production of high-performance golf balls endowed with durability, scuff resistance and optimal hardness without a loss of rebound in the molded article.

1 . A method for preparing a golf ball material composed of a blend of the following essential components A to C:
 (A) an olefin-containing thermoplastic polymer having an acid content of at least 0.5 wt % but less than 5.0 wt %;   (B) a resin composition comprising one or more selected from the group consisting of diene polymers, thermoplastic polymers and thermoset polymers; and   (C) an oxygen-containing inorganic metal compound;   the method being characterized by melt-mixing component A and component B at a temperature which exceeds the melting points of both components to form a resin composition thereof, then blending in with component C so as to enable at least some of the acid groups present in the resin composition of components A and B to be neutralized.   
     
     
         2 . The method of  claim 1 , wherein component C is blended into the resin composition of components A and B after preparation as a master batch. 
     
     
         3 . The method of  claim 1 , wherein component C is blended into the resin composition of components A and B in the form of a finely ground metal oxide. 
     
     
         4 . The method of  claim 1 , wherein a twin-screw extruder is used to melt-mix components A and B. 
     
     
         5 . The method of  claim 4 , wherein the twin-screw extruder has a length-to-diameter (L/D) ratio of at least 20. 
     
     
         6 . The method of  claim 4 , wherein the twin-screw extruder has a screw segment arrangement such that a kneading disc zone within the extruder has an L/D ratio which is 10 to 90% of the whole L/D ratio. 
     
     
         7 . The method of  claim 4 , wherein the kneading disc zone of the twin-screw extruder includes right-handed kneading discs, left-handed kneading discs, reverse discs, and various neutral discs. 
     
     
         8 . The method of  claim 4 , wherein the twin-screw extruder has a screw diameter of at least 15 mm. 
     
     
         9 . The method of  claim 4 , wherein the twin-screw extruder has a vent port and a vacuum line connected thereto. 
     
     
         10 . The method of  claim 1 , wherein the twin-screw extruder is equipped with a device for the dropwise addition or pressurized injection of a liquid. 
     
     
         11 . The method of  claim 10 , wherein the liquid is a compound of the formula ROH, R being hydrogen or an alkyl group, and is added in an amount, based on the resin extrusion output, of 0.1 to 10 wt %.