| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a practice golf ball which is endowed with the properties required of practice balls intended for long-term use, including better durability to cracking and durability of appearance than ordinary game balls and the ability to maintain a stable feel on impact and a stable carry performance over a long period of time, and which, moreover, by further limiting the carry of the ball, has a controlled carry for use at very small practice fields. <P>SOLUTION: The 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, a crosslinking initiator and a metal oxide. The base rubber is a mixture of polybutadiene with styrene-butadiene rubber and/or isoprene rubber, and the co-crosslinking agent is methacrylic acid. The core has a specific deflection CH under a specific load, and the ball has a specific initial velocity. The dimples on the surface of the ball have a volume ratio (VR) of from 0.95 to 1.7. The practice golf ball is endowed with the properties required of practice balls intended for long-term use, includes better durability to cracking and durability of appearance than ordinary game balls and the ability to maintain a stable feel on impact and a stable carry performance over a long period of time, and moreover, by further limiting the carry of the ball, has a controlled carry for use at very small practice fields. <P>COPYRIGHT: (C)2013,JPO&INPIT |
