| 摘要 |
Golf ball 2 has a spherical core 4 , a reinforcing layer 6 positioned outside of the core 4 and a cover 8 positioned outside of the reinforcing layer 6 . The core 4 has a inner sphere 10 , a first mid layer 12 positioned outside of the inner sphere 10 , and a second mid layer 14 positioned outside of the first mid layer 12 . The principal component of the first mid layer 12 and the second mid layer 14 is an ionomer resin. The principal component of the cover 8 is a thermoplastic polyurethane elastomer. The second mid layer 14 has a hardness Hs which is greater than a hardness Hf of the first mid layer 12 and a hardness Hc of the cover 8 . The hardness Hc of the cover 8 is equal to or less than 50. A product (Tc.Hc) of a thickness Tc (mm) and a hardness Hc of the cover 8 is equal to or less than 25.
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