| abstract |
(57) [Summary] (Corrected) [SOLUTION] A solid core, an envelope layer formed on the solid core, an intermediate layer formed on the envelope layer, and an intermediate layer formed on the intermediate layer And at least one of the envelope layer, the intermediate layer and the cover is (a) an olefin-unsaturated carboxylic acid random copolymer and / or an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester random copolymer. And (b) a fatty acid or a derivative thereof having a molecular weight of 280 or more, (c) a basic inorganic metal compound capable of neutralizing an acid group in the components (a) and (b), and the cover Has a Shore D hardness of 45-6 8, and each Shore D hardness of the surrounding layer, the intermediate layer, and the cover satisfies the relationship of hardness of the surrounding layer ≦ hardness of the intermediate layer ≦ hardness of the cover. [Effect] It has excellent hit feeling, controllability, durability, and flight distance performance. |