| 摘要 |
A practice golf ball has a core and a cover. The core is made of a rubber composition which includes a base rubber, a co-crosslinking agent which is methacrylic acid, a crosslinking initiator and a metal oxide. The respective ingredients in the rubber composition are formulated in specific amounts, and the core has an optimized hardness profile. The cover includes a resin component which is composed primarily of polyurethane. The cover has a thickness of 0.3 mm to 1.9 mm, and a material hardness, expressed as the Shore D hardness, of 30 to 48. The respective deflections of the core and the ball under a specific load, and the relationship therebetween, are optimized. The volume ratio VR of dimples on the surface of the ball is optimized.
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