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(11) | EP 2 668 977 A3 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Golf ball |
(57) A golf ball 2 includes a spherical core 4 and a cover 6 covering the core 4. The
cover 6 includes an inner cover 8 and an outer cover 10 positioned outside the inner
cover 8. When distances (%) from a central point of the core 4 to nine points and
hardnesses at the nine points, which nine points are obtained by dividing a region
from the central point to a surface of the core 4 at intervals of 12.5% of a radius
of the core 4, are plotted in a graph, R2 of a linear approximation curve obtained by a least-square method is 0.95 or greater.
A hardness of an innermost layer of the cover 6 is greater than a surface hardness
of the core 4. Preferably, the core is obtained by a rubber composition being crosslinked.
The rubber composition includes an acid and/or a salt (d).
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