Golf ball

Abstract

In a golf ball having a core of one or more layer, an intermediate layer and a cover, the cover consists of an inner cover layer and an outer cover layer, the inner cover layer and the outer cover layer being made of materials having hardnesses on the Shore D hardness scale of, respectively, from 20 to 40 and from 35 to 55, and the inner and outer cover layers having a combined thickness of from 0.6 to 1.2 mm. Also, letting (A) and (B) be the rebound resiliences (%) of, respectively, the inner cover layer material and the outer cover layer material based on JIS-K 6255, the ball satisfies the condition 0%<(A)−(B)<18%. This ball exhibits a higher spin rate on approach shots and a good feel without lowering the distance performance on shots with a driver (W #1).

1 . A golf ball comprising a core of one or more layer, an intermediate layer and a cover, wherein the cover consists of an inner cover layer and an outer cover layer, the inner cover layer being made of a material having a hardness on the Shore D hardness scale of from 20 to 40, the outer cover layer being made of a material having a hardness on the Shore D hardness scale of from 35 to 55 and the inner and outer cover layers having a combined thickness of from 0.6 to 1.2 mm, and wherein, letting (A) be the rebound resilience (%) of the inner cover layer material based on JIS-K 6255 and (B) be the rebound resilience (%) of the outer cover layer material based on JIS-K 6255, the ball satisfies the condition 0%<(A)−(B)<18%. 
     
     
         2 . The golf ball of  claim 1 , wherein the outer cover layer material comprises a resin component which is a thermoplastic polyurethane elastomer. 
     
     
         3 . The golf ball of  claim 1 , wherein the inner cover layer material comprises a resin component which is a thermoplastic elastomer. 
     
     
         4 . The golf ball of  claim 1 , wherein the inner cover layer material comprises a resin component which is a multi-component copolymer having conjugated diene units, non-conjugated olefin units and aromatic vinyl units, the conjugated diene units including butadiene units, the non-conjugated olefin units including units selected from ethylene units, propylene units and 1-butene units, the aromatic vinyl units including styrene units, and the content of the conjugated diene units in the multi-component copolymer being at least 5 wt %. 
     
     
         5 . The golf ball of  claim 4 , wherein the content of the conjugated diene units in the multi-component copolymer is at least 10 wt %. 
     
     
         6 . The golf ball of  claim 4 , wherein the content of the non-conjugated olefin units in the multi-component copolymer is up to 90 wt %. 
     
     
         7 . The golf ball of  claim 4 , wherein the content of the aromatic vinyl units in the multi-component copolymer is up to 30 wt %. 
     
     
         8 . The golf ball of  claim 4 , wherein the non-conjugated olefin units are ethylene units. 
     
     
         9 . The golf ball of  claim 4 , wherein the multi-component copolymer is a copolymer polymerized with a gadolinium metallocene complex catalyst. 
     
     
         10 . The golf ball of  claim 1 , wherein the inner cover layer has a thickness of from 0.1 to 0.5 mm. 
     
     
         11 . The golf ball of  claim 1 , wherein the intermediate layer, the inner cover layer and the outer cover layer have a thickness relationship therebetween which satisfies the following condition:
   intermediate layer thickness>inner cover layer thickness<outer cover layer thickness.   
     
     
         12 . The golf ball of  claim 1 , wherein the ratio (a)/(b) between the inner cover layer thickness (a) and the outer cover layer thickness (b) is from 0.10 to 0.60.