Abstract: A golf ball 2 includes a core 4, a mid layer 6, a reinforcing layer 8, and a cover 10. A hardness Hm of the mid layer 6 is greater than a hardness Hc of the cover 10. A difference (Hm?Hc) is greater than 28. A hardness Hs2 at a surface of a sphere consisting of the core 4 and the mid layer 6 is greater than a hardness Hs3 at a surface of the golf ball 2. A difference (Hs2?Hs3) is less than 5. A thickness Tm of the mid layer 6 is larger than a thickness Tc of the cover 10. A ratio (Tm/Tc) is greater than 3.0 and less than 5.0. A diameter of the core 4 is equal to or greater than 38.2 mm. The hardness Hc of the cover 10 is equal to or less than 37.

Abstract: A golf ball 2 includes a core 4, amid layer 6 positioned outside the core 4, a reinforcing layer 8 positioned outside the mid layer 6, and a cover 10 positioned outside the reinforcing layer 8. The core 4 is obtained by a rubber composition being crosslinked. The rubber composition includes a base rubber, a co-crosslinking agent, a crosslinking initiator, and a carboxylate. The co-crosslinking agent is: (1) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms; and/or (2) a metal salt of an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms. The amount of the carboxylate is equal to or greater than 1.0 parts by weight but less than 40 parts by weight per 100 parts by weight of the base rubber. A hardness of the mid layer 6 is greater than a hardness of the cover 10.

Abstract: A golf ball 2 includes a core 4, a mid layer 6, a reinforcing layer 8, and a cover 10. When distances (%) from the central point of the core 4 to nine points and JIS-C hardnesses at the nine points, which are obtained by dividing a region from the central point of the core 4 to the surface of the core 4 at intervals of 12.5% of the radius of the core 4, are plotted in a graph, R2 of a linear approximation curve obtained by a least-square method is equal to or greater than 0.95. The difference (H(100)?H(0)) between a JIS-C hardness H(100) at the surface of the core 4 and a JIS-C hardness H(0) at the central point of the core 4 is equal to or greater than 15.

Abstract: A core 4 of a golf ball 2 includes a center 10 and an envelope layer 12 positioned outside the center 10. The ratio of the volume of the core 4 to the volume of a phantom sphere of the golf ball 2 is equal to or greater than 78%. The difference (He?Ho) between a JIS-C hardness He at the surface of the core 4 and a JIS-C hardness Ho at the central point of the core 4 is equal to or greater than 15 but equal to or less than 40. The difference (H1?Ho) between a JIS-C hardness H1 at a point P1 that is located radially outward of the boundary between the center 10 and the envelope layer 12 and whose distance from the boundary is 1 mm and the JIS-C hardness Ho is equal to or greater than 0 but equal to or less than 2.

Abstract: An object of the present invention is to provide a golf ball having an improved controllability and shot feeling while maintaining a flight distance on driver shots. The present invention provides 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, and has a specific hardness distribution, and the intermediate layer is formed from an intermediate layer composition comprising, as a resin component, (A) a modified polyester elastomer and (B) a binary ionomer resin, and having a flexural modulus ranging from 150 MPa to 450 MPa, a maximum loss factor (tan ?) between ?20° C. and 0° C. of 0.08 or less, a repulsive modulus of 55% or more, and a slab hardness ranging from 60 to 90 in JIS-hardness.

Abstract: A golf ball 2 includes a core 4, amid layer 6, and a cover 8. The core 4 includes a center 10 and an envelope layer 12. The ratio (Do/De) of an amount of compressive deformation Do of the center 10 to an amount of compressive deformation De of the core 4 is equal to or greater than 1.5 but equal to or less than 2.5. The ratio (Do/Dc) of the amount of compressive deformation Do of the center 10 to an amount of compressive deformation Dc of the golf ball 2 is equal to or greater than 1.8. The diameter of the center 10 is equal to or less than 20 mm. The difference (He-Ho) between a surface hardness He of the core 4 and a central hardness Ho of the center 10 is equal to or less than 40.

Abstract: A golf ball 2 includes a core 4, a mid layer 6, and a cover 8. The core 4 includes a center 10 and an envelope layer 12. The ratio of the volume Ve of the core 4 to the volume of a phantom sphere of the golf ball 2 is equal to greater than 76%. The ratio (Co/Ce) of an amount of compressive deformation Co of the center 10 to an amount of compressive deformation Ce of the core 4 is greater than 2.0 but less than 3.0. The ratio (Vo/Ve) of the volume Vo of the center 10 to the volume Ve of the core 4 is equal to or greater than 0.01 but equal to or less than 0.13.

Abstract: A golf ball 2 includes a core 4, a mid layer 6, and a cover 8. The core 4 includes a center 10 and an envelope layer 12. The ratio of the volume Ve of the core 4 to the volume of a phantom sphere of the golf ball 2 is equal to greater than 76%. The ratio (Co/Do) of an amount of compressive deformation Co of the center 10 to the diameter Do of the center 10 is equal to or greater than 0.085 but equal to or less than 0.130. The ratio (Ce/De) of an amount of compressive deformation Ce of the core 4 to the diameter De of the core 4 is equal to or greater than 0.015 but equal to or less than 0.020.

Abstract: A golf ball 2 includes a spherical core 4, a mid layer 6 outside the core 4, and a cover 8 outside the mid layer 6. The core 4 includes a spherical center 10 and an envelope layer 12 outside the center 10. At all points P included in a zone that extends over a distance range from equal to or greater than 1 mm to equal to or less than 15 mm from the central point of the core 4, the following mathematical formula is satisfied. ?5<H2?H1<5 In the mathematical formula, H1 indicates the JIS-C hardness at a point P1 located radially inward of each point P at a distance of 1 mm from the point P, and H2 indicates the JIS-C hardness at a point P2 located radially outward of each point P at a distance of 1 mm from the point P.

Abstract: At all points Pa in a zone A extending over a distance range from equal to or greater than 1 mm to less than 5 mm from the central point of a core 4, a mathematical formula, Ha2?Ha1<5, is satisfied. At any of points Pb in a zone B extending over a distance range from equal to or greater than 5 mm to equal to or less than 10 mm from the central point of the core 4, a mathematical formula, Hb2?Hb1?5, is satisfied. Ha1 and Ha2 indicate JIS-C hardnesses at points Pa1 and Pa2 located radially inward and outward of each point Pa at a distance of 1 mm from the point Pa. Hb1 and Hb2 indicate JIS-C hardnesses at points Pb1 and Pb2 located radially inward and outward of the point Pb at a distance of 1 mm from the point Pb.

Abstract: At all points Pa included in zone “A” away from the central point of the core 4 at a distance of 1 mm or greater and less than 5 mm, the following mathematical expression (I) is satisfied, and at any point Pb included in zone “B” away from the central point of the core 4 at a distance of 5 mm or greater and 10 mm or less, the following mathematical expression (II) is satisfied. Ha2?Ha1<5??(I) Hb2?Hb1?5??(II) Ha1 represents the hardness at a point Pa1 that is located inside the point Pa along the radial direction and away from the point Pa at a distance of 1 mm, and Ha2 represents the hardness at a point Pa2 that is located outside the point Pa along the radial direction and away from the point Pa at a distance of 1 mm.

Abstract: A golf ball 2 has a spherical core 4, a mid layer 6 situated on the external side of the core 4, and a cover 8 situated on the external side of the mid layer 6. The core 4 has a spherical center 10 and an envelope layer 12 situated on the external side of the center 10. At all points P included in a zone away from the central point of the core 4 at a distance of 1 mm or greater and 15 mm or less, the following mathematical expression is satisfied. H2?H1?5 In the above mathematical expression, H1 represents the JIS-C hardness at a point P1 that is located inside the point P along the radial direction and away from the point P at a distance of 1 mm, and H2 represents the JIS-C hardness at a point P2 that is located outside the point P along the radial direction and away from the point P at a distance of 1 mm.

Abstract: Golf ball 2 has spherical core 4, cover 6 situated on the external side of the core 4, and paint layer 8 situated on the external side of the cover 6. The cover 6 has a Shore D hardness of no greater than 61. The paint layer 8 has a Martens hardness of no greater than 2.0 mgf/?m2. The base polymer of the paint layer 8 is a polyurethane obtained by a reaction of a polyol with a polyisocyanate. The polyisocyanate contains a buret-modified form of hexamethylene diisocyanate. The cover 6 has a thickness of 0.3 mm or greater and 1.0 mm or less. The paint layer 8 has a thickness of 5 ?m or greater and 40 ?m or less.

Abstract: The present invention provides a lysophospholipid of the formula (I) 1