| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a golf ball of multilayer structure with at least three layers improved in carry performance without degrading controllability and a hitting sensation demanded by a skilled player. <P>SOLUTION: The golf ball includes a core formed of a rubber composition containing a mixture of polybutadiene, unsaturated carboxylic acid metal salt, organic peroxide, and thiophenols or metal salt thereof, and an intermediate layer formed of ionomer resin or a mixture of ionomer resin and thermoplastic elastomer. The intermediate layer is harder than a cover and the surface of the elastic core, and has a thickness of 0.5-3 mm and a Shore D hardness of 50-67. The core is gradually increased in hardness from the center part toward the outside. The JIS-C hardness of the center part is 50-65, and the difference in JIS-C hardness between the center and the surface is 23-24. A value obtained by subtracting the hardness of the cover from the hardness of the intermediate layer is 2 or more in Shore D hardness, and the difference in hardness between the intermediate layer and the core surface is 6-22 in JIS-C hardness. The thickness of the cover is 0.6-2.1 mm. A carry of the golf ball can thereby be increased when hit with a driver, and the golf ball has excellent spin performance with good controllability in an approach shot while providing a good hitting sensation so as to be usable with satisfaction particularly by the skilled player. <P>COPYRIGHT: (C)2013,JPO&INPIT |
