Multi-piece golf ball
View Patent ↗An object of the present invention is to provide a golf ball showing low spin rate on driver shots and high spin rate on approach shots. The present invention provides a multi-piece golf ball comprising a spherical center, at least two envelope layers covering the spherical center, and a cover covering the envelope layers, wherein the envelope layers comprise at least a first envelope layer covering the spherical center, and a second envelope layer covering the first envelope layer, a material hardness (H0) of the spherical center, a material hardness (H1) of the first envelope layer, and a material hardness (H2) of the second envelope layer satisfy an equation of H0>H1>H2, and the material hardness (H2) of the second envelope layer is lowest among the material hardness of the center constituent material and material hardness of envelope layer constituent materials.
1. A multi-piece golf ball comprising a spherical center, at least two envelope layers covering the spherical center, and a cover covering the envelope layers, wherein
the envelope layers comprise at least a first envelope layer covering the spherical center, and a second envelope layer covering the first envelope layer,
a material hardness (H0) of the spherical center, a material hardness (H1) of the first envelope layer, and a material hardness (H2) of the second envelope layer satisfy a relationship H0>H1>H2,
the material hardness (H2) of the second envelope layer is 30 or less in Shore D hardness and lowest among the material hardness of the center and all layers, including all envelope layers, between the center and the cover,
a hardness difference (H1−H2) between the material hardness (H1) of the first envelope layer and the material hardness (H2) of the second envelope layer ranges from 1 to 30 in Shore D hardness, and
the material hardness (H0) of the spherical center is 35 or less in Shore D hardness.
2. The multi-piece golf ball according to claim 1 , wherein a hardness difference (H0−H2) between the material hardness (H2) of the second envelope layer and the material hardness (H0) of the spherical center is 5 or more in Shore D hardness.
3. The multi-piece golf ball according to claim 1 , wherein a material hardness (Hc) of the cover ranges from 5 to 55 in Shore D hardness.
4. The multi-piece golf ball according to claim 1 , wherein the first envelope layer has a thickness of 15 mm or less, and the second envelope layer has a thickness of 20 mm or less.
5. The multi-piece golf ball according to claim 1 , wherein the second envelope layer has a thickness of 2.5 mm or more and 20 mm or less, and the first envelope layer has a thickness of 2.5 mm or less.
6. The multi-piece golf ball according to claim 1 , wherein the cover has a thickness of 2 mm or less.
7. The multi-piece golf ball according to claim 1 , wherein the spherical center has a diameter ranging from 5 mm to 25 mm.
8. The multi-piece golf ball according to claim 1 , wherein a hardness difference (H0−H1) between the material hardness (H0) of the spherical center and the material hardness (H1) of the first envelope layer ranges from 1 to 30 in Shore D hardness.
9. A multi-piece golf ball comprising a spherical center, at least four envelope layers covering the spherical center, and a cover covering the envelope layers,
wherein
the envelope layers comprise at least four layers including at least a first envelope layer covering the spherical center, a second envelope layer covering the first envelope layer, and an outermost envelope layer located on the outermost side of the envelope layers;
a material hardness (H0) of the spherical center, a material hardness (H1) of the first envelope layer, and a material hardness (H2) of the second envelope layer satisfy a relationship H0>H1>H2;
the material hardness (H2) of the second envelope layer is lowest among the material hardness of the center and all layers, including all envelope layers, between the center and the cover;
a material hardness (Hn) of the outermost envelope layer is highest among the material hardness of the center, the cover and all layers, including all envelope layers, between the center and the cover; and
a material hardness (Hx) of an envelope layer disposed between the second envelope layer and the outermost envelope layer, the material hardness (H2) of the second envelope layer, and the material hardness (Hn) of the outermost envelope layer satisfy a relationship H2<Hx<Hn.
10. The multi-piece golf ball according to claim 9 , wherein the material hardness (H2) of the second envelope layer is 30 or less in Shore D hardness.
11. The multi-piece golf ball according to claim 9 , wherein a hardness difference (Hn−H2) between the material hardness (H2) of the second envelope layer and the material hardness (Hn) of the outermost envelope layer is 25 or more in Shore D hardness.
12. The multi-piece golf ball according to claim 9 , wherein a hardness difference (H0−H2) between the material hardness (H2) of the second envelope layer and the material hardness (H0) of the spherical center is 5 or more in Shore D hardness.
13. The multi-piece golf ball according to claim 9 , wherein the material hardness (H0) of the spherical center is 55 or less in Shore D hardness.
14. The multi-piece golf ball according to claim 9 , wherein the material hardness (H1) of the first envelope layer ranges from 10 to 50 in Shore D hardness.
15. The multi-piece golf ball according to claim 9 , wherein the material hardness (Hn) of the outermost envelope layer ranges from 30 to 85 in Shore D hardness.
16. The multi-piece golf ball according to claim 9 , wherein a material hardness (Hc) of the cover ranges from 5 to 55 in Shore D hardness.
17. The multi-piece golf ball according to claim 9 , wherein the first envelope layer has a thickness of 15 mm or less, and the material hardness (H0) of the spherical center is 35 or less in Shore D hardness.
18. The multi-piece golf ball according to claim 9 , wherein the second envelope layer has a thickness of 2.5 mm or more and 20 mm or less, and the first envelope layer has a thickness of 2.5 mm or less.
19. The multi-piece golf ball according to claim 9 , wherein the outermost envelope layer has a thickness of 5 mm or less.
20. The multi-piece golf ball according to claim 9 , wherein the cover has a thickness of 2 mm or less.
21. The multi-piece golf ball according to claim 9 , wherein the envelope layer disposed between the second envelope layer and the outermost envelope layer has a thickness of 15 mm or less and is formed from a thermoplastic resin composition containing an ionomer resin as a resin component.
22. The multi-piece golf ball according to claim 9 , wherein the spherical center has a diameter ranging from 5 mm to 25 mm.
23. The multi-piece golf ball according to claim 9 , wherein a hardness difference (H0−H1) between the material hardness (H0) of the spherical center and the material hardness (H1) of the first envelope layer ranges from 1 to 30 in Shore D hardness.
24. The multi-piece golf ball according to claim 9 , wherein a hardness difference (H1−H2) between the material hardness (H1) of the first envelope layer and the material hardness (H2) of the second envelope layer ranges from 1 to 30 in Shore D hardness, and the material hardness (H0) of the spherical center is 35 or less in Shore D hardness.
25. The multi-piece golf ball according to claim 9 , wherein a hardness difference (Hn−H0) between the material hardness (Hn) of the outermost envelope layer and the material hardness (H0) of the spherical center ranges from 1 to 70 in Shore D hardness.