Patent ID: 7909710

Claim:
A multi-piece solid golf ball comprising a solid core, a cover, at least one intermediate layer situated therebetween, and a plurality of dimples on a surface of the ball, wherein the solid core has a diameter of from 34 to 38.7 mm, a deflection when compressed under a final load of 130 kgf from an initial load of 10 kgf of from 3.5 to 6.0 mm, a Shore D hardness at a center of the core of from 20 to 38, a Shore D hardness in a region 5 mm to 10 mm from the core center of from 23 to 41, a Shore D hardness 15 mm from the core center of from 28 to 46, and a Shore D hardness at a surface of the core of from 37 to 62; the intermediate layer is composed primarily of a material obtained by mixing under applied heat: 100 parts by weight of a resin component of (a) from 95 to 50 wt % of an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester random copolymer and/or a metal salt thereof, (b) from 0 to 20 wt % of an olefin-unsaturated carboxylic acid random copolymer and/or a metal salt thereof, and (c) from 5 to 50 wt % of a thermoplastic block copolymer composed of a crystalline polyolefin block and a polyethylene/butylene random copolymer, (d) from 5 to 170 parts by weight of a fatty acid or fatty acid derivative having a molecular weight of from 280 to 1500, and (e) from 0.1 to 10 parts by weight of a basic inorganic metal compound capable of neutralizing acid groups within components (a) and (d); the intermediate layer has a thickness of from 1.0 to 2.5 mm; the intermediate layer material has a Shore D hardness of from 35 to 60 and has a Shore D hardness difference with the surface of the solid core of within ±10; the cover is formed primarily of polyurethane, has a thickness of from 0.5 to 1.5 mm, and has a Shore D hardness of from 53 to 65 which is higher than the intermediate layer hardness, the Shore D hardness difference therebetween being from 6 to 15; the cover and the intermediate layer have a combined thickness of from 1.5 to 3.5 mm; and the overall ball has a deflection, when compressed under a final load of 130 kgf from an initial load of 10 kgf, of from 2.9 to 5.0 mm.