Golf ball resin composition and golf ball

1. A golf ball resin composition containing:

(A) a thermoplastic resin having an infrared absorption peak in a region from 3200 cm −1 to 3600 cm −1 , and including a thermoplastic resin having a hydroxyl group, and a thermoplastic resin having an amino group and/or a thermoplastic resin having an imino group, and

(B) at least one resin component selected from the group consisting of (b-1) a binary copolymer composed of an olefin and an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms, (b-2) a metal ion-neutralized product of a binary copolymer composed of an olefin and an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms, (b-3) a ternary copolymer composed of an olefin, an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms and an α,β-unsaturated carboxylic acid ester, and (b-4) a metal ion-neutralized product of a ternary copolymer composed of an olefin, an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms and an α,β-unsaturated carboxylic acid ester,

wherein the thermoplastic resin having the hydroxyl group is at least one member selected from the group consisting of an ethylene-vinyl alcohol copolymer having the ethylene component in an amount of from 15 mole % to 60 mole %, a partially saponified product of an ethylene-vinyl acetate copolymer and a polyvinyl alcohol,

a mass ratio of the component (A) to the component (B) ranges from 5/95 to 25/75, and

when a relaxation modulus Er (−20° C., 9%) of the golf ball resin composition is measured under conditions of −20° C. and a strain of 9%, a relaxation curve is plotted with the relaxation modulus (MPa) as the vertical axis and a logarithm (ln(t)) of time (second) as the horizontal axis, and the relaxation curve is linearly approximated to obtain a linear approximation curve, the linear approximation curve has a slope in an absolute value of 7 or more.

2. The golf ball resin composition according to claim 1 , wherein the mass ratio of the component (A) to the component (B) ranges from 5/95 to 20/80.

3. A golf ball resin composition containing:

(A) a thermoplastic resin having an infrared absorption peak in a region from 3200 cm −1 to 3600 cm −1 , and

(B) at least one resin component selected from the group consisting of (b-1) a binary copolymer composed of an olefin and an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms, (b-2) a metal ion-neutralized product of a binary copolymer composed of an olefin and an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms, (b-3) a ternary copolymer composed of an olefin, an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms and an α,β-unsaturated carboxylic acid ester, and (b-4) a metal ion-neutralized product of a ternary copolymer composed of an olefin, an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms and an α,β-unsaturated carboxylic acid ester,

wherein the component (A) is a mixture of an ethylene-vinyl alcohol copolymer and a polyamide,

a mass ratio of the component (A) to the component (B) ranges from 5/95 to 25/75, and

when a relaxation modulus Er (−20° C., 9%) of the golf ball resin composition is measured under conditions of −20° C. and a strain of 9%, a relaxation curve is plotted with the relaxation modulus (MPa) as the vertical axis and a logarithm (ln(t)) of time (second) as the horizontal axis, and the relaxation curve is linearly approximated to obtain a linear approximation curve, the linear approximation curve has a slope in an absolute value of 7 or more.

4. The golf ball resin composition according to claim 3 , wherein the mass ratio of the component (A) to the component (B) ranges from 5/95 to 20/80.

5. A golf ball having a core, at least one intermediate layer covering the core, and a cover covering the at least one intermediate layer, wherein the at least one intermediate layer is formed from a golf ball resin composition containing:

(A) a thermoplastic resin having an infrared absorption peak in a region from 3200 cm −1 to 3600 cm −1 , and

(B) at least one resin component selected from the group consisting of (b-1) a binary copolymer composed of an olefin and an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms, (b-2) a metal ion-neutralized product of a binary copolymer composed of an olefin and an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms, (b-3) a ternary copolymer composed of an olefin, an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms and an α,β-unsaturated carboxylic acid ester, and (b-4) a metal ion-neutralized product of a ternary copolymer composed of an olefin, an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms and an α,β-unsaturated carboxylic acid ester,

wherein the component (A) is a mixture of an ethylene-vinyl alcohol copolymer and a polyamide, and a mass ratio of the component (A) to the component (B) ranges from 5/95 to 45/55,

wherein when a relaxation modulus Er (−20° C., 9%) of the golf ball resin composition is measured under conditions of −20° C. and a strain of 9%, a relaxation curve is plotted with the relaxation modulus (MPa) as the vertical axis and a logarithm (ln(t)) of time (second) as the horizontal axis, and the relaxation curve is linearly approximated to obtain a linear approximation curve, the linear approximation curve has a slope in an absolute value of 7 or more, and

wherein the at least one intermediate layer has a thickness of from 1.0 mm to 2.5 mm.

6. The golf ball according to claim 5 , wherein (A) the thermoplastic resin has an infrared absorption peak in a region from 2800 cm −1 to 3000 cm −1 , and a ratio (A 2800-3000 /A 3200-3600 ) of an absorbance of the infrared absorption peak in the region from 2800 cm −1 to 3000 cm −1 to an absorbance of the infrared absorption peak in the region from 3200 cm −1 to 3600 cm −1 is 0.5 or more and 3.0 or less.

7. The golf ball according to claim 5 , wherein (A) the thermoplastic resin has a bending stiffness ranging from 300 MPa to 5,000 MPa.

8. The golf ball according to claim 5 , wherein (A) the thermoplastic resin has a slab hardness of 50 or more and 95 or less in Shore D hardness.

9. The golf ball according to claim 5 , wherein the golf ball resin composition has a bending stiffness ranging from 250 MPa to 1,000 MPa.

10. The golf ball according to claim 5 , wherein the golf ball resin composition has a slab hardness of 50 or more and 90 or less in Shore D hardness.

11. The golf ball according to claim 5 , wherein the golf ball resin composition has rebound resilience of 40% or more.

12. A golf ball having a core, at least one intermediate layer covering the core, and a cover covering the at least one intermediate layer, wherein the at least one intermediate layer is formed from a golf ball resin composition containing:

(A) a thermoplastic resin having an infrared absorption peak in a region from 3200 cm −1 to 3600 cm −1 , and including a thermoplastic resin having a hydroxyl group, and a thermoplastic resin having an amino group and/or a thermoplastic resin having an imino group, and

(B) at least one resin component selected from the group consisting of (b-1) a binary copolymer composed of an olefin and an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms, (b-2) a metal ion-neutralized product of a binary copolymer composed of an olefin and an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms, (b-3) a ternary copolymer composed of an olefin, an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms and an α,β-unsaturated carboxylic acid ester, and (b-4) a metal ion-neutralized product of a ternary copolymer composed of an olefin, an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms and an α,β-unsaturated carboxylic acid ester,

wherein the thermoplastic resin having the hydroxyl group is at least one member selected from the group consisting of an ethylene-vinyl alcohol copolymer having the ethylene component in an amount of from 15 mole % to 60 mole %, a partially saponified product of an ethylene-vinyl acetate copolymer and a polyvinyl alcohol,

a mass ratio of the component (A) to the component (B) ranges from 5/95 to 45/55,

when a relaxation modulus Er (−20° C., 9%) of the golf ball resin composition is measured under conditions of −20° C. and a strain of 9%, a relaxation curve is plotted with the relaxation modulus (MPa) as the vertical axis and a logarithm (ln(t)) of time (second) as the horizontal axis, and the relaxation curve is linearly approximated to obtain a linear approximation curve, the linear approximation curve has a slope in an absolute value of 7 or more, and

the at least one intermediate layer has a thickness of from 1.0 mm to 2.5 mm.

13. The golf ball according to claim 12 , wherein (A) the thermoplastic resin has an infrared absorption peak in a region from 2800 cm −1 to 3000 cm −1 , and a ratio (A 2800-3000 /A 3200-3600 ) of an absorbance of the infrared absorption peak in the region from 2800 cm −1 to 3000 cm −1 to an absorbance of the infrared absorption peak in the region from 3200 cm −1 to 3600 cm −1 is 0.5 or more and 3.0 or less.

14. The golf ball according to claim 12 , wherein (A) the thermoplastic resin has a bending stiffness ranging from 300 MPa to 5,000 MPa.

15. The golf ball according to claim 12 , wherein (A) the thermoplastic resin has a slab hardness of 50 or more and 95 or less in Shore D hardness.

16. The golf ball according to claim 12 , wherein the golf ball resin composition has a bending stiffness ranging from 250 MPa to 1,000 MPa.

17. The golf ball according to claim 12 , wherein the golf ball resin composition has a slab hardness of 50 or more and 90 or less in Shore D hardness.

18. The golf ball according to claim 12 , wherein the golf ball resin composition has rebound resilience of 40% or more.