Patent ID: 8951147
Filing Date: 2015-02-10
Classification: A63B

Abstract:
1. A golf ball having a core, an intermediate layer disposed around the core and a cover disposed around the intermediate layer, wherein the core has a center and an envelope layer disposed around the center, wherein a difference (He−Ho) between a JIS-C hardness He at the surface of the core and a JIS-C hardness Ho at the central point of the core is in a range from 15 to 30, and a JIS-C hardness Hc of the cover is less than the JIS-C hardness Ho at the central point of the core, wherein at all points P included in a zone at a distance of 1 mm to 15 mm from the central point of the core, a following mathematical expression is satisfied: (in the above mathematical expression, H1 represents a JIS-C hardness at a point P1 that is located inside the point P along the radial direction and at a distance of 1 mm from the point P, and H2 represents a JIS-C hardness at a point P2 that is located outside the point P along the radial direction and at a distance of 1 mm from the point P), and wherein the intermediate layer is formed from an intermediate layer composition having a flexural modulus ranging from 150 MPa to 450 MPa, a maximum loss factor (tan δ) between −20° C. and 0° C. of 0.08 or less, a rebound resilience of 55% or more, and a slab hardness ranging from 60 to 90 in JIS-C hardness, and the intermediate layer composition comprises, as a resin component, 30 mass % to 70 mass % of (A) a modified polyester elastomer having a Shore A hardness of 95 or less; 70 mass % to 30 mass % of (B) a binary ionomer resin having a Shore D hardness of 65 or more, a flexural modulus of 300 MPa or more, and a melt flow rate (190° C., 2.16 kg) of 1.0 g/10 min or more; and 0 mass % to 50 mass % of (C) a thermoplastic resin other than (A) component and (B) component (provided that a total content of (A) component, (B) component, and (C) component is 100 mass %).