Golf ball and method of manufacture

Abstract

In a golf ball having a core and a cover, the cover is formed of a resin composition made chiefly of a polyurethane resin having a crosslink density of at least 1.4×10 2 mol/m 3 and not more than 35×10 2 mol/m 3 , so that the golf ball has an excellent controllability on approach shots and an excellent scuff resistance compared with golf balls having a conventional urethane cover.

1 . A golf ball comprising a core and a cover, wherein the cover is formed of a resin composition made chiefly of a polyurethane resin having a crosslink density of at least 1.4×10 2  mol/m 3  and not more than 35×10 2  mol/m 3 . 
     
     
         2 . The golf ball of  claim 1 , wherein the polyurethane resin includes a polyol component which is polytetramethylene glycol (PTMG) and, letting T×10 2  mol/m 3  be the crosslink density of the polyurethane resin, D be the Shore D hardness of the golf ball cover and Mn be the number-average molecular weight of the polytetramethylene glycol (PTMG), the value expressed as (T/D)×Mn is 1,000 or less. 
     
     
         3 . The golf ball of  claim 2 , wherein the value of T/D is 0.6 or less. 
     
     
         4 . The golf ball of  claim 2 , wherein the value of Mn is 1,000 or more. 
     
     
         5 . The golf ball of  claim 2 , wherein the value of Mn is 2,000 or more. 
     
     
         6 . The golf ball of  claim 2 , wherein the value of Mn is 3,000 or more. 
     
     
         7 . The golf ball of  claim 1 , wherein the cover has a thickness of 1.5 mm or less. 
     
     
         8 . The golf ball of  claim 1 , wherein the polyurethane resin has a Shore D hardness of from 30 to 60. 
     
     
         9 . A method of manufacturing golf balls having a core and a cover, which method comprises the step of forming the cover from a resin composition made chiefly of a polyurethane resin having a crosslink density, as measured by the toluene swelling test, of at least 1.4×10 2  mol/m 3  and not more than 35×10 2  mol/m 3 .