An object of the present invention is to provide a golf ball excellent in resilience and durability, with a good moldability of the intermediate layer. The present invention provides a golf ball having a center, a cover, and an intermediate layer disposed between the center and the cover, 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 40 to 60 in Shore D 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 %).
1. A golf ball having a center, a cover, and an intermediate layer disposed between the center and the cover, 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 40 to 60 in Shore D 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;
0.1 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 %);
wherein (A) the modified polyester elastomer is obtained by a reaction between (a-3) an unsaturated carboxylic acid or a derivative thereof and (a-2) a polyester elastomer containing a polyalkylene glycol component in a presence of (a-1) a radical generator,
wherein a blending ratio of (a-3) the unsaturated carboxylic acid or a derivative thereof ranges from 0.01 mass % to 30 mass % with respect to 100 mass % of (a-2) the polyester elastomer,
wherein a content of the polyalkylene glycol component in (a-2) the polyester elastomer is in a range from 5 mass % to 90 mass %, and
wherein (a-3) the unsaturated carboxylic acid or a derivative thereof comprises an unsaturated carboxylic anhydride or an unsaturated carboxylic acid ester,
wherein a content of an acid component in (B) the binary ionomer resin is 16 mass % or more, and
wherein (C) component is at least one member selected from the group consisting of polyurethane, polyolefin, polyester obtained by reacting polytetramethylene glycol with polybutylene terephthalate, polyamide, polystyrene, polycarbonate, polyacetal, modified poly(phenyleneether), polyimide, polysulfone, polyethersulfone, poly(phenylenesulfide), polyarylate, polyamideimide, polyetherimide, polyetheretherketone, polyetherketone, polytetrafluroroethylene, polyaminobismaleimide, polybisamidetriazole, an acrylonitrile-butadiene-styrene copolymer, an acrylonitrile-styrene copolymer, and an acrylonitrile-EPDM-styrene copolymer.
2. The golf ball according to claim 1 , wherein the intermediate layer composition contains at least one filler selected from the group consisting of gold, tungsten, lead, copper, iron, cast iron, pig iron, zinc, titanium, aluminum, zirconium, aluminum oxide, bismuth oxide, cerium oxide, copper oxide, tin oxide, titanium oxide, yttrium oxide, zinc oxide, silica, barium sulfate, calcium carbonate, talc, montmorillonite, and mica in an amount ranging from 1 part to 40 parts by mass with respect to 100 parts by mass of the resin component.
3. The golf ball according to claim 1 , wherein the intermediate layer has a thickness ranging from 0.5 mm to 1.2 mm, and the cover has a thickness ranging from 0.3 mm to 1.0 mm.
4. The golf ball according to claim 1 , wherein the intermediate layer composition has a slab hardness ranging from 53 to 60 in Shore D hardness, and the intermediate layer has a density of 1.00 g/cm 3 or more.
5. The golf ball according to claim 1 , wherein the cover has a Shore D hardness of 57 or more.
6. The golf ball according to claim 1 , wherein the intermediate layer has mass W 2 that is larger than mass W 3 of the cover and a sum (W 2 +W 3 ) of the mass of the intermediate layer and the cover is 8.4 g or more and less than 12.0 g.
7. The golf ball according to claim 1 , wherein a sum (V 2 +V 3 ) of a volume V 2 of the intermediate layer and a volume V 3 of the cover is 10.0 cm 3 or less.
8. The golf ball according to claim 1 , wherein a blending ratio of (a-1) the radical generator ranges from 0.001 mass % to 3 mass % with respect to 100 mass % of (a-2) the polyester elastomer.
9. The golf ball according to claim 1 , wherein the intermediate layer composition has a melt flow rate (230° C., 2.16 kg) ranging from 3 g/10 min to 30 g/10 min.
10. The golf ball according to claim 1 , wherein the center has a central hardness H 1 c ranging from 25 to 55 in Shore D hardness.
11. The golf ball according to claim 1 , wherein the center has a surface hardness H 1 s ranging from 35 to 65 in Shore D hardness.
12. The golf ball according to claim 1 , wherein the center has a density G 1 ranging from 1.00 g/cm 3 to 1.18 g/cm 3 .
13. The golf ball according to claim 1 , wherein the center has a compression deformation amount from 3.3 mm to 7.0 mm, when applying an initial load of 98 N to a final load of 1275 N to the center.
14. The golf ball according to claim 1 , wherein the core has a compression deformation amount from 3.2 mm to 6.5 mm, when applying an initial load of 98 N to a final load of 1275 N to the core.
15. The golf ball according to claim 1 , wherein the cover has a density G 3 ranging from 0.97 g/cm 3 to 1.20 g/cm 3 .
16. The golf ball according to claim 1 wherein the golf ball has a compression deformation amount from 2.5 mm to 3.8 mm, when applying an initial load of 98 N to a final load of 1275 N to the golf ball.
17. The golf ball according to claim 1 , wherein a difference (G 2 −G 1 ) between a density G 2 of the intermediate layer and a density G 1 of the center ranges from 0.01 g/cm 3 to 0.20 g/cm 3 .
18. The golf ball according to claim 1 , wherein (B) the binary ionomer resin has a melt flow rate (190° C., 2.16 kg) of 3.4 g/10 min or more.
19. The golf ball according to claim 1 , wherein a degree of neutralization of carboxylic groups contained in (B) the binary ionomer resin is 20 mole % or more and 90 mole % or less.