Golf ball
An object of the present invention is to provide a golf ball travelling a great flight distance on driver shots, exhibiting an excellent spin performance on approach shots under a dry condition and a wet condition, and showing an excellent shot feeling and durability. The present invention provides a golf ball comprising a golf ball body having a spherical core, an intermediate layer and a cover, and a paint film composed of two or more layers, wherein a 10% elastic modulus difference (M in −M out ) between an innermost layer and an outermost layer of the paint film is 25 kgf/cm 2 or more.
1. A golf ball comprising a golf ball body and a paint film formed on a surface of the golf ball body,
wherein the golf ball body comprises a spherical core, an intermediate layer covering the spherical core and a cover covering the intermediate layer, and the paint film has a multi-layered construction composed of two or more layers,
wherein a difference (M in −M out ) between a 10% elastic modulus (M in ) of an innermost layer of the paint film and a 10% elastic modulus (M out ) of an outermost layer of the paint film is 25 kgf/cm 2 or more, and
wherein the 10% elastic modulus (M in ) of the innermost layer of the paint film is 100 kgf/cm 2 or more.
2. The golf ball according to claim 1 , wherein the intermediate layer has a thickness Tm of 0.75 mm or more.
3. The golf ball according to claim 1 , wherein the cover has a material hardness Hc of 40 or less in Shore D hardness.
4. The golf ball according to claim 1 , wherein the intermediate layer has a material hardness Hm of 55 or more in Shore D hardness.
5. The golf ball according to claim 1 , wherein a hardness difference (surface hardness-center hardness) HDc (Shore C hardness) between a surface hardness and a center hardness of the spherical core, a material hardness Hm (Shore D hardness) of the intermediate layer, a thickness Tc (mm) of the cover, and a material hardness Hc (Shore D hardness) of the cover satisfy the following mathematical formula (1):
( HDc×Hm )/( Hc×Tc )>63 Mathematical formula (1).
6. The golf ball according to claim 1 , wherein a volume Vm (mm 3 ) and a material hardness Hm (Shore D hardness) of the intermediate layer, a phantom volume Vc (mm 3 ) and a material hardness Hc (Shore D hardness) of the cover satisfy the following mathematical formula (2):
3.0<( Vm×Hm )/( Vc×Hc )<7.5 Mathematical formula (2).
7. The golf ball according to claim 1 , wherein the 10% elastic modulus (M out ) of the outermost layer of the paint film is less than 100 kgf/cm 2 .
8. The golf ball according to claim 1 , wherein the innermost layer of the paint film has a thickness (T in ) ranging from 5 μm to 30 μm, and the outermost layer of the paint film has a thickness (T out ) ranging from 5 μm to 30 μm.
9. The golf ball according to claim 1 , wherein the intermediate layer has a thickness Tm of 0.8 mm or more.
10. The golf ball according to claim 5 , wherein the hardness difference HDc ranges from 15 to 40 in Shore C hardness.
11. The golf ball according to claim 5 , wherein the surface hardness of the spherical core ranges from 75 to 90 in Shore C hardness.
12. The golf ball according to claim 5 , wherein the center hardness of the spherical core ranges from 45 to 70 in Shore C hardness.
13. The golf ball according to claim 1 , wherein the spherical core is a dual-layered core composed of a spherical center and an outer core covering the spherical center.
14. The golf ball according to claim 6 , wherein the volume Vm of the intermediate layer ranges from 3900 mm 3 to 9500 mm 3 .
15. The golf ball according to claim 5 , wherein the thickness Tc of the cover ranges from 0.2 mm to 0.7 mm.
16. The golf ball according to claim 6 , wherein the phantom volume Vc of the cover ranges from 1100 mm 3 to 3900 mm 3 .
17. The golf ball according to claim 1 , wherein the 10% elastic modulus (M in ) of the innermost layer of the paint film is 500 kgf/cm 2 or less.
18. The golf ball according to claim 7 , wherein the 10% elastic modulus (M out ) of the outermost layer of the paint film is 5 kgf/cm 2 or more.
19. The golf ball according to claim 1 , wherein a base resin constituting the paint film includes a polyurethane resin.
20. The golf ball according to claim 1 , wherein
the intermediate layer has a thickness Tm of 0.75 mm or more;
the cover has a material hardness Hc of 40 or less in Shore D hardness;
a hardness difference (surface hardness-center hardness) HDc (Shore C hardness) between a surface hardness and a center hardness of the spherical core, a material hardness Hm (Shore D hardness) of the intermediate layer, a thickness Tc (mm) of the cover, and a material hardness Hc (Shore D hardness) of the cover satisfy the following mathematical formula (1); and
a volume Vm (mm 3 ) and a material hardness Hm (Shore D hardness) of the intermediate layer, a phantom volume Vc (mm 3 ) and a material hardness Hc (Shore D hardness) of the cover satisfy the following mathematical formula (2):
( HDc×Hm )/( Hc×Tc )>63 formula (1);
3.0<( Vm×Hm )/( Vc×Hc )<7.5 formula (2).