Patent ID: 8366568

Claim:
A golf ball comprising a core and a cover positioned outside the core, wherein the core includes a center and an envelope layer positioned outside the center, the center has a diameter of 1 mm or greater and 15 mm or less, the center has a JIS-C hardness H1, at its central point, of 20 or greater and 50 or less, a difference (H4-H3) between a JIS-C hardness H4 of the core at its surface and a JIS-C hardness H3 of the envelope layer at its innermost portion is equal to or greater than 10, the cover has a flexural modulus of 300 MPa or greater and 1000 MPa or less, the cover has a tensile modulus of 400 MPa or greater and 1500 MPa or less, and the cover is formed from a resin composition that includes: (A) a highly elastic polyamide resin with a flexural modulus of 700 MPa or greater and 5000 MPa or less, (B) an ethylene-(meth)acrylic acid copolymer that is neutralized with a metal ion, and (C) a resin having a polar functional group, a weight ratio of the polyamide resin (A) with respect to the copolymer (B) is equal to or greater than 5/95 and equal to or less than 80/20, wherein the amount of the resin (C) is equal to or greater than 0.1 part by weight and equal to or less than 20 parts by weight, per total 100 parts by weight of the polyamide resin (A) and the copolymer (B).