Patent ID: 8523707

Claim:
A multi-piece solid golf ball comprising a core, an envelope layer enclosing the core, an intermediate layer enclosing the envelope layer, and a cover which encloses the intermediate layer and has formed on a surface thereof a plurality of dimples, wherein the core is formed primarily of a rubber material and has a diameter of at least 31 mm, the envelope layer and the intermediate layer are each formed primarily of the same or different resin materials and the cover is formed primarily of polyurethane; the envelope layer, intermediate layer and cover have thicknesses which satisfy the relationship cover thickness<intermediate layer thickness<envelope layer thickness; and the envelope layer, intermediate layer and cover have surface hardnesses (Durometer D hardness) which satisfy the relationship core surface hardness<envelope layer surface hardness<intermediate layer surface hardness>cover surface hardness, wherein the resin material of which the envelope layer is formed is a material comprising, in admixture, a base resin of (a) an olefin-unsaturated carboxylic acid binary random copolymer and/or a metal ion-neutralized product of an olefin-unsaturated carboxylic acid binary random copolymer mixed with (b) an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester ternary random copolymer and/or a metal ion-neutralized product of an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester ternary random copolymer in a weight ratio between 100:0 and 0:100, and (e) a non-ionomeric thermoplastic elastomer in a weight ratio between 100:0 and 50:50.