| 摘要 |
PROBLEM TO BE SOLVED: To increase durability and to remarkably extend the carry of a ball after actually hitting the ball by enlarging the inertia moment. SOLUTION: This ball for a ball game having a diameter of 50 to 70 mm is composed of: a spherical core having a hollow part and an enclosing layer covering the hollow part; and one or more layers of covers covering the spherical core part. In the ball, the diameter of the hollow part ranges from 51 to 75% of the whole ball, the Shore D hardness of the enclosing layer is 55 to 70, and the Shore D hardness of the outermost layer of the cover is 55 to 70. COPYRIGHT: (C)2006,JPO&NCIPI
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