Golf ball material and golf ball

1. A golf ball material having a ratio [Shore D/log(bending stiffness)] of Shore D hardness to a logarithm of bending stiffness (kgf/cm 2 ) of 19.0 or more and a bending stiffness of 300 kgf/cm 2 or less, and comprising a thermoplastic elastomer as a resin component and a flake-like or needle-like filler as a filler, in an amount ranging from 10 parts to 100 parts by mass based on 100 parts by mass of the resin component.

2. The golf ball material according to claim 1 , having a Shore D hardness of 15 D or more.

3. The golf ball material according to claim 1 , wherein the filler includes a layered silicate or an organically modified layered silicate.

4. The golf ball material according to claim 3 , wherein each layer constituting the layered silicate has a thickness of 10 nm or less when the filler includes layered silicate or each layer constituting the organically modified layered silicate has a thickness of 10 nm or less when the filler includes organically modified layered silicate.

5. The golf ball material according to claim 3 , wherein each layer constituting the layered silicate has a flat shape with a length of 1 μm or less and a width of 1 μm or less when the filler includes layered silicate or each layer constituting the organically modified layered silicate has a flat shape with a length of 1 μm or less and a width of 1 μm or less when the filler includes organically modified layered silicate.

6. The golf ball material according to claim 3 , wherein the filler includes layered silicate, and

wherein the layered silicate has a cation exchange capacity ranging from 30 meq/100 g to 200 meq/100 g.

7. The golf ball material according to claim 3 , wherein the filler includes organically modified layered silicate, and

wherein the organically modified layered silicate has an ion exchange rate of 50 mole % or more.

8. The golf ball material according to claim 1 , wherein the thermoplastic elastomer includes a thermoplastic polyurethane elastomer.

9. The golf ball material according to claim 8 , wherein a polyol component constituting the thermoplastic polyurethane elastomer includes polytetramethylene ether glycol.

10. The golf ball material according to claim 8 , wherein the polyisocyanate component constituting the thermoplastic polyurethane elastomer includes dicyclohexylmethane diisocyanate.

11. The golf ball material according to claim 8 , wherein the chain extender component constituting the thermoplastic polyurethane elastomer includes butane diol.

12. A golf ball comprising a core and a cover covering the core, wherein the cover is formed from a golf ball material having a ratio [Shore D/log(bending stiffness)] of Shore D hardness to a logarithm of bending stiffness (kgf/cm 2 ) of 19.0 or more and a bending stiffness of 300 kgf/cm 2 or less, and comprising a thermoplastic elastomer as a resin component and a flake-like or needle-like filler as a filler, in an amount ranging from 10 parts to 100 parts by mass based on 100 parts by mass of the resin component.

13. The golf ball according to claim 12 , wherein the golf ball has a multi-layered core having a center and at least one intermediate layer covering the center.

14. The golf ball according to claim 13 , wherein the intermediate layer has a thickness ranging from 0.3 mm to 6.0 mm and a slab hardness ranging from 40 to 80 in Shore D hardness.

15. The golf ball according to claim 12 , wherein the core has a surface hardness ranging from 65 to 100 and a center hardness ranging from 45 to 70 in JIS-C hardness and a hardness difference ranging from 10 to 40 in JIS-C hardness between the surface hardness and the center hardness thereof.

16. The golf ball according to claim 12 , wherein the cover has a thickness ranging from 0.3 mm to 2.0 mm.

17. The golf ball according to claim 12 , wherein the golf ball material comprises a thermoplastic polyurethane elastomer as a resin component and a layered silicate or an organically modified layered silicate as a filler.