Golf ball resin composition and golf ball using the same

1. A golf ball resin composition consisting of,

100 parts by mass of (A) an ionomer resin consisting of a metal ion-neutralized product of a ternary copolymer composed of ethylene, α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms and α,β-unsaturated carboxylic acid ester,

from 70 parts to 100 parts by mass of (B) a metal salt of a fatty acid having 18 to 30 carbon atoms, and

optionally calcium carbonate and/or barium sulfate as a specific gravity adjusting agent, a pigment component, a dispersant, an antioxidant, an ultraviolet absorber, a light stabilizer, a fluorescent material, and/or a fluorescent brightener,

wherein (A) the ionomer resin has a content of α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms in a range from 2 mass % to 30 mass %,

(A) the ionomer resin is neutralized with zinc or sodium, and

the golf ball resin composition has a melt flow rate (190° C., 2.16 kg) in a range from 14.7 g/10 min to 600 g/10 min, a bending stiffness in a range from 100 MPa to 450 MPa and a rebound resilience in a range from 40% to 80%,

wherein an area A under a peak around 1600 cm −1 attributed to neutralized carboxyl groups and an area B under a peak around 1700 cm −1 attributed to non-neutralized carboxyl groups in a spectrum obtained by analyzing the golf ball resin composition by FT-IR satisfy an equation of

0.90 ≤P=A /( A+B )≤0.97, and

an area A0 under a peak around 1600 cm −1 attributed to neutralized carboxyl groups and an area B0 under a peak around 1700 cm −1 attributed to non-neutralized carboxyl groups in a spectrum obtained by analyzing (A) the ionomer resin by FT-IR satisfy an equation of

0.50 ≤P 0 =A 0/( A 0 +B 0)≤0.78.

2. The golf ball resin composition according to claim 1 , wherein a fatty acid component of (B) the metal salt of the fatty acid is stearic acid, behenic acid, or montanic acid.

3. The golf ball resin composition according to claim 1 , wherein a metal component of (B) the metal salt of the fatty acid is magnesium, calcium, or barium.

4. The golf ball resin composition according to claim 1 , wherein the golf ball resin composition has a slab hardness ranging from 20 to 70 in a Shore D hardness.

5. The golf ball resin composition according to claim 1 , wherein the golf ball resin composition contains (B) the metal salt of a fatty acid in an amount of from 84 parts to 100 parts by mass with respect to 100 parts by mass of (A) the ionomer resin.

6. A multi-piece golf ball comprising

a core having a center and at least one intermediate layer disposed around the center, and

a cover disposed around the core, wherein at least one of the intermediate layer is formed from a golf ball resin composition consisting of,

100 parts by mass of (A) an ionomer resin consisting of a metal ion-neutralized product of a ternary copolymer composed of ethylene, α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms and α,β-unsaturated carboxylic acid ester,

from 70 parts to 100 parts by mass of (B) a metal salt of a fatty acid having 18 to 30 carbon atoms, and

optionally calcium carbonate and/or barium sulfate as a specific gravity adjusting agent, a pigment component, a dispersant, an antioxidant, an ultraviolet absorber, a light stabilizer, a fluorescent material, and/or a fluorescent brightener,

wherein (A) the ionomer resin has a content of α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms in a range from 2 mass % to 30 mass %,

the golf ball resin composition has a melt flow rate (190° C., 2.16 kg) in a range from 14.7 g/10 min to 600 g/10 min, a bending stiffness in a range from 100 MPa to 450 MPa and a rebound resilience in a range from 40% to 80%,

wherein the core surface hardness is greater than the core center hardness by 4 or larger and 40 or less in Shore D hardness,

wherein an area A under a peak around 1600 cm −1 attributed to neutralized carboxyl groups and an area B under a peak around 1700 cm −1 attributed to non-neutralized carboxyl groups in a spectrum obtained by analyzing the golf ball resin composition by FT-IR satisfy an equation of

0.90 ≤P=A /( A+B )≤0.97, and

an area A0 under a peak around 1600 cm −1 attributed to neutralized carboxyl groups and an area B0 under a peak around 1700 cm −1 attributed to non-neutralized carboxyl groups in a spectrum obtained by analyzing (A) the ionomer resin by FT-IR satisfy an equation of

0.50 ≤P 0 =A 0/( A 0 +B 0)≤0.78.

7. The multi-piece golf ball according to claim 6 , wherein (A) the ionomer resin is neutralized with magnesium, zinc or sodium.

8. The multi-piece golf ball according to claim 6 , wherein a fatty acid component of (B) the metal salt of the fatty acid is stearic acid, behenic acid, or montanic acid.

9. The multi-piece golf ball according to claim 6 , wherein a metal component of (B) the metal salt of the fatty acid is magnesium, calcium, or barium.

10. The multi-piece golf ball according to claim 6 , wherein the golf ball resin composition has a slab hardness ranging from 20 to 70 in a Shore D hardness.

11. The multi-piece golf ball according to claim 6 , wherein the intermediate layer has a thickness of 0.5 mm or more, and less than 2.5 mm.

12. The multi-piece golf ball according to claim 6 , wherein the cover comprises an ionomer resin as a resin component.

13. The multi-piece golf ball according to claim 6 , wherein the golf ball resin composition contains (B) the metal salt of a fatty acid in an amount of from 84 parts to 100 parts by mass with respect to 100 parts by mass of (A) the ionomer resin.