| 摘要 |
Golf ball 2 has a core 4 , a mid layer 6 , a reinforcing layer 8 , a cover 10 and dimples 12 . Base polymer of the mid layer 6 includes an ionomer resin as a principal component. The reinforcing layer 8 includes a thermosetting resin as a base polymer. Base polymer of the cover 10 includes a thermoplastic polyurethane elastomer as a principal component. The cover 10 has a thickness Tc of equal to or less than 0.6 mm. The cover has a hardness Hc of equal to or less than 54. The cover has a volume V of equal to or less than 3.0 cm<SUP>3</SUP>. Product obtained by multiplying the thickness Tc, the hardness Hc and the volume V is equal to or less than 90. Ratio (Dx/Dn), which is a ratio of a mean diameter of the dimples ranking in the top 10% Dx to a mean diameter of the dimples ranking in the bottom 10% Dn when all the dimples are arranged in decreasing order of the diameter is equal to or greater than 1.30. Standard deviation eta of the diameter of all the dimples is equal to or less than 0.52. |
