Multi-piece golf ball

A multi-piece golf ball comprising a solid core, a surrounding layer enclosing the solid core, an intermediate layer enclosing the surrounding layer, and a cover enclosing the intermediate layer, wherein

• at least one of said surrounding layer, said intermediate layer and said cover is formed of a heated mixture comprising
• (d) 100 parts by weight of a metal ion-neutralized olefin-unsaturated carboxylic acid random copolymer or a metal ion-neutralized olefin-unsaturated carboxylic acid-unsaturated carboxylate random copolymer or both,
• (b) 5 to 80 parts by weight of a fatty acid or fatty acid derivative having a molecular weight of at least 280, and
• (c) 0.1 to 10 parts by weight of a basic inorganic metal compound capable of neutralizing acid groups in components (d) and (b), said heated mixture having a melt index of at least 1.0 dg/min,
• said surrounding layer has a Shore D hardness of 10 to 55, said intermediate layer has a Shore D hardness of 40 to 63, said cover has a Shore D hardness of 45 to 68, the Shore D hardness of said surrounding layer is not greater than the Shore D hardness of said intermediate layer, which is not greater than the Shore D hardness of said cover.

A multi-piece golf ball comprising a solid core, a surrounding layer enclosing the solid core, an intermediate layer enclosing the surrounding layer, and a cover enclosing the intermediate layer, wherein

• at least one of said surrounding layer, said intermediate layer and said cover is formed of a heated mixture comprising
• 100 parts by weight of a mixture of (a) an olefin-unsaturated carboxylic acid random copolymer or an olefin-unsaturated carboxylic acid-unsaturated carboxylate random copolymer or both and (d) a metal ion-neutralized olefin-unsaturated carboxylic acid random copolymer or a metal ion-neutralized olefin-unsaturated carboxylic acid-unsaturated carboxylate random copolymer or both,
• (b) 5 to 80 parts by weight of a fatty acid or fatty acid derivative having a molecular weight of at least 280, and
• (c) 0.1 to 10 parts by weight of a basic inorganic metal compound capable of neutralizing acid groups in components (a), (d) and (b), said heated mixture having a melt index of at least 1.0 dg/min,
• said surrounding layer has a Shore D hardness of 10 to 55, said intermediate layer has a Shore D hardness of 40 to 63, said cover has a Shore D hardness of 45 to 68, the Shore D hardness of said surrounding layer is not greater than the Shore D hardness of said intermediate layer, which is not greater than the Shore D hardness of said cover.