Golf ball

Abstract

The present invention, by forming the outermost layer of a golf ball cover from a specific resin composition that includes a thermoplastic resin and a color masterbatch having mutually similar specific gravities, provides a golf ball which is imparted with an excellent durability of markings thereon, a uniform and evenly colored appearance, and an excellent manufacturability.

1 . A golf ball comprising a core and a cover of at least one layer encasing the core, wherein an outermost layer of the cover is formed of a resin composition comprising:
 (A) a thermoplastic resin, and   (B) a color masterbatch,   
       which color masterbatch (B) includes
 (b-1) a thermoplastic resin, 
 (b-2) a colorant, 
 (b-3) titanium oxide, 
 (b-4) a fatty acid metal salt, and 
 (b-5) a dispersant, 
 
       component (b-4) being included in an amount of from 0.3 to 1.4 parts by weight per 100 parts by weight of component (A) and component (b-1) combined, the ratio (B)/(A) of the specific gravity of component (A) to the specific gravity of component (B) being from 0.8 to 1.2, and component (A) and component (b-1) having weight-average molecular weights (Mw) of at least 100,000. 
     
     
         2 . The golf ball of  claim 1 , wherein the thermoplastic resin (A) is one or more selected from the group consisting of:
 (a-1) an olefin-unsaturated carboxylic acid copolymer,   (a-2) a metal ion neutralization product of an olefin-unsaturated carboxylic acid copolymer,   (a-3) an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester terpolymer, and   (a-4) a metal ion neutralization product of an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester terpolymer.   
     
     
         3 . The golf ball of  claim 2 , wherein at least 30 wt % of the unsaturated carboxylic acid included in (a-2) the metal ion neutralization product of an olefin-unsaturated carboxylic acid copolymer and/or (a-4) the metal ion neutralization product of an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester terpolymer is neutralized with metal ions. 
     
     
         4 . The golf ball of  claim 2 , wherein (a-2) the metal ion neutralization product of an olefin-unsaturated carboxylic acid copolymer and/or (a-4) the metal ion neutralization product of an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester terpolymer include as the metal ions one or more selected from the group consisting of Li + , Na + , Mg ++ , Ca ++  and Zn ++ . 
     
     
         5 . The golf ball of  claim 2 , wherein component (A) further includes (a-5) one or more selected from the group consisting of polyethylene, thermoplastic polyurethane and rubbery elastomer. 
     
     
         6 . The golf ball of  claim 1 , wherein the thermoplastic resin serving as component (b-1) is one or more selected from the group consisting of:
 (b-1-1) an olefin-unsaturated carboxylic acid copolymer, and   (b-1-2) an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester terpolymer.   
     
     
         7 . The golf ball of  claim 1 , wherein the thermoplastic resin serving as component (b-1) has a melt flow rate (MFR) of from 5 to 60 g/10 min. 
     
     
         8 . The golf ball of  claim 1 , wherein the colorant (b-2) is one or more selected from the group consisting of red, blue, yellow, orange, green, violet and black colorants. 
     
     
         9 . The golf ball of  claim 1 , wherein the fatty acid metal salt (b-4) is a metal salt of a fatty acid having from 16 to 30 carbons. 
     
     
         10 . The golf ball of  claim 1 , wherein the fatty acid component of the fatty acid metal salt (b-4) is one or more selected from the group consisting of stearic acid, oleic acid, behenic acid and montanic acid. 
     
     
         11 . The golf ball of  claim 1 , wherein the metal ion of the fatty acid metal salt (b-4) is one or more selected from the group consisting of Li + , Na + , Mg ++ , Ca ++  and Zn ++ . 
     
     
         12 . The golf ball of  claim 1 , wherein component (B) is included in an amount of from 3 to 25 parts by weight per 100 parts by weight of component (A).