An object of the present invention is to provide a golf ball showing a low spin rate on driver shots and a high spin rate on approach shots. The present invention provides a golf ball comprising a spherical center, at least two envelope layers covering the spherical center, and a cover covering the envelope layers, wherein an envelope layer (Es 1 ) formed from a material having a lowest material hardness among a center constituent material and envelope layers constituent materials, is disposed in a region located at a distance from 36.0% to 65.0% of a golf ball radius from a center point of the golf ball.
1. A golf ball comprising a spherical center, at least four envelope layers covering the spherical center, and a cover covering the envelope layers,
wherein an envelope layer (Es 1 ), which is formed from a material having a material hardness (Hs 1 ) that is lowest among the center and other envelope layers, is disposed in a region located at a radial distance of from 36.0% to 65.0% of the golf ball radius from the golf ball center point,
an envelope layer (Eh 1 ), which is formed from a material having a material hardness (Hh 1 ) that is highest among the center, cover and other envelope layers, is disposed in a region located at a radial distance of from 85.0% to 99.5% of the golf ball radius from the golf ball center point,
an envelope layer (E 11 ) is disposed between the spherical center and the envelope layer (Es 1 ), and
a material hardness (H 11 ) of the envelope layer (E 11 ) is higher than the material hardness (Hs 1 ) of the envelope layer (Es 1 ) and smaller than a material hardness (Ho 1 ) of the spherical center.
2. The golf ball according to claim 1 , wherein the envelope layer (Es 1 ) is disposed in a region located at a radial distance of from 40.0% to 62.5% of the golf ball radius from the golf ball center point.
3. The golf ball according to claim 1 , wherein a hardness difference (Hh 1 −Hs 1 ) between the material hardness (Hs 1 ) of the envelope layer (Es 1 ) and the material hardness (Hh 1 ) of the envelope layer (Eh 1 ) is 30 or more in Shore D hardness.
4. The golf ball according to claim 1 , wherein a hardness difference (Ho 1 −Hs 1 ) between the material hardness (Hs 1 ) of the envelope layer (Es 1 ) and the material hardness (Ho 1 ) of the spherical center is 1 or more in Shore D hardness.
5. The golf ball according to claim 1 , wherein the envelope layer (Es 1 ) has the material hardness (Hs 1 ) of 30 or less in Shore D hardness.
6. The golf ball according to claim 1 , wherein a hardness difference (Hh 1 −Ho 1 ) between the material hardness (Hh 1 ) of the envelope layer (Eh 1 ) and the material hardness (Ho 1 ) of the spherical center is 1 or more in Shore D hardness.
7. The golf ball according to claim 1 , wherein the envelope layer (Eh 1 ) has the material hardness (Hh 1 ) of 30 or more in Shore D hardness.
8. The golf ball according to claim 3 , wherein a hardness difference (Ho 1 −Hs 1 ) between the material hardness (Hs 1 ) of the envelope layer (Es 1 ) and the material hardness (Ho 1 ) of the spherical center is 1 or more in Shore D hardness, and a hardness difference (Hh 1 −Ho 1 ) between the material hardness (Hh 1 ) of the envelope layer (Eh 1 ) and the material hardness (Ho 1 ) of the spherical center is 1 or more in Shore D hardness.
9. The golf ball according to claim 8 , wherein the envelope layer (Es 1 ) has the material hardness (Hs 1 ) of 30 or less in Shore D hardness, and the envelope layer (Eh 1 ) has the material hardness (Hh 1 ) of 30 or more in Shore D hardness.
10. The golf ball according to claim 1 , wherein the spherical center has the material hardness (Ho 1 ) in a range from 15 to 55 in Shore D hardness.
11. The golf ball according to claim 1 , wherein
the golf ball has a diameter ranging from 40 mm to 45 mm,
the diameter of the spherical center is 20 mm or less,
the thickness of the envelope layer (Eh 1 ) is 3 mm or less, and
the thickness of the cover is 1.0 mm or less.
12. The golf ball according to claim 1 , wherein the hardness (Shore D hardness) ratio (Hh 1 /Hs 1 ) between the material hardness (Hs 1 ) of the envelope layer (Es 1 ) and the material hardness (Hh 1 ) of the envelope layer (Eh 1 ) ranges from 1.1 to 35.
13. The golf ball according to claim 1 , wherein the hardness (Shore D hardness) ratio (Ho 1 /Hs 1 ) between the material hardness (Hs 1 ) of the envelope layer (Es 1 ) and the material hardness (Ho 1 ) of the center ranges from 1.05 to 20.
14. The golf ball according to claim 1 , wherein the hardness (Shore D hardness) ratio (Hh 1 /Ho 1 ) between the material hardness (Hh 1 ) of the envelope layer (Eh 1 ) and the material hardness (Ho 1 ) of the center ranges from 1.0 to 2.4.
15. The golf ball according to claim 1 , wherein
the spherical center has a diameter in a range from 5 mm to 25 mm, and
the compression deformation amount (deformation amount of the center along the compression direction) of the spherical center when applying a load from 98 N as an initial load to 1275 N as a final load to the spherical center ranges from 1.5 mm to 5.0 mm.
16. The golf ball according to claim 1 , wherein the thickness of the envelope layer other than the envelope layer (Es 1 ) and the envelope layer (Eh 1 ) ranges from 0.1 mm to 15 mm.
17. The golf ball according to claim 1 , wherein a material hardness (Hc 1 ) of the cover ranges from 5 to 55 in Shore D hardness.
18. The golf ball according to claim 1 , wherein
the golf ball has a diameter in a range from 40 mm to 45 mm, and
the compression deformation amount (deformation amount along the compression direction) of the golf ball when applying a load from 98 N as an initial load to 1275 N as a final load to the golf ball ranges from 2.0 mm to 4.0 mm.