Golf club grip, golf club and method for producing golf club grip

1. A golf club grip comprising a cylindrical grip body having a cylindrical inner layer and a cylindrical outer layer covering the cylindrical inner layer, and a grip end provided on a butt side end of the cylindrical grip body,

wherein the cylindrical outer layer is formed from a rubber composition containing a carboxyl-modified acrylonitrile-butadiene rubber and/or a carboxyl-modified hydrogenated acrylonitrile-butadiene rubber as a base rubber,

wherein the cylindrical inner layer is formed from a second rubber composition containing at least one rubber selected from the group consisting of a natural rubber, ethylene-propylene-diene rubber, butyl rubber, acrylonitrile-butadiene rubber, hydrogenated acrylonitrile-butadiene rubber, carboxyl-modified acrylonitrile-butadiene rubber, butadiene rubber, styrene-butadiene rubber, polyurethane rubber, isoprene rubber, chloroprene rubber, and ethylene-propylene rubber as a base rubber,

wherein the grip end is formed from a first rubber composition containing an acrylonitrile-butadiene based rubber as a base rubber,

wherein the cylindrical inner layer and the cylindrical outer layer almost have the same length in the axis direction, or the cylindrical outer layer is longer than the cylindrical inner layer on the tip side,

wherein the cylindrical outer layer is interposed in a space between a butt side end edge of the cylindrical inner layer and the grip end,

wherein a butt side end part of the cylindrical outer layer is folded back to cover the butt side end edge of the cylindrical inner layer and a butt side inner surface of the cylindrical inner layer, and

wherein a length L 2 is 0.5 mm or more and 14.5 mm or less, wherein L 2 is a length where the cylindrical outer layer covers the butt side inner surface of the cylindrical inner layer in the grip axis direction.

2. The golf club grip according to claim 1 , wherein the acrylonitrile-butadiene based rubber of the first rubber composition of the grip end is at least one selected from the group consisting of a carboxyl-modified acrylonitrile-butadiene rubber, a hydrogenated acrylonitrile-butadiene rubber, and a carboxyl-modified hydrogenated acrylonitrile-butadiene rubber.

3. The golf club grip according to claim 1 , wherein the cylindrical inner layer is a porous rubber layer.

4. The golf club grip according to claim 3 , wherein the porous rubber layer has a foaming ratio ranging from 1.2 to 5.0.

5. The golf club grip according to claim 1 , wherein the cylindrical outer layer is a solid layer.

6. The golf club grip according to claim 1 , wherein the golf club grip is obtained by press molding a laminated product and a grip end in a mold, and

wherein the laminated product comprises an unvulcanized rubber sheet formed from the rubber composition containing a carboxyl-modified acrylonitrile-butadiene rubber and/or a carboxyl-modified hydrogenated acrylonitrile-butadiene rubber as a base rubber and an unvulcanized rubber sheet formed from the second rubber composition, and the grip end is formed from the first rubber composition.

7. The golf club grip according to claim 1 , wherein the cylindrical inner layer is a foamed layer formed from the second rubber composition,

wherein the second rubber composition contains the base rubber and microballoons, and

wherein the amount of the microballoons in the second rubber composition is 5 parts by mass or more, and 20 parts by mass or less, with respect to 100 parts by mass of the base rubber.

8. The golf club grip according to claim 1 , wherein the rubber composition used for the cylindrical outer layer and the first rubber composition used for the grip end contain the same base rubber.

9. The golf club grip according to claim 1 , wherein the golf club grip has, at the end part thereof on the tip side, a folded back part formed by folding back the cylindrical outer layer inwardly.

10. The golf club grip according to claim 9 , wherein a length in the grip axis direction L 4 of the folded back part is 4 mm or more and 30 mm or less.

11. A golf club comprising:

a shaft,

a head provided on one end of the shaft, and

a grip provided on another end of the shaft, wherein the grip is a golf club grip comprising a cylindrical grip body having a cylindrical inner layer and a cylindrical outer layer covering the cylindrical inner layer, and a grip end is provided on a butt side end of the cylindrical grip body,

wherein the cylindrical inner layer is formed from a second rubber composition containing at least rubber selected from the group consisting of a natural rubber, ethylene-propylene-diene rubber, butyl rubber, acrylonitrile-butadiene rubber, hydrogenated acrylonitrile-butadiene rubber, carboxyl-modified acrylonitrile-butadiene rubber, butadiene rubber, styrene-butadiene rubber, polyurethane rubber, isoprene rubber, chloroprene rubber, and ethylene-propylene rubber as a base rubber,

wherein the grip end is formed from a first rubber composition containing an acrylonitrile-butadiene based rubber as a base rubber,

wherein the cylindrical inner layer and the cylindrical outer layer almost have the same length in the axis direction, or the cylindrical outer layer is longer than the cylindrical inner layer on the tip side,

wherein the cylindrical outer layer is interposed in a space between a butt side end edge of the cylindrical inner layer and the grip end,

wherein a butt side end part of the cylindrical outer layer is folded back to cover the butt side end edge of the cylindrical inner layer and a butt side inner surface of the cylindrical inner layer, and

wherein a length L 2 is 0.5 mm or more and 14.5 mm or less, wherein L 2 is a length where the cylindrical outer layer covers the butt side inner surface of the cylindrical inner layer in the grip axis direction.

12. The golf club according to claim 11 , wherein the acrylonitrile-butadiene based rubber of the first rubber composition of the grip end is at least one selected from the group consisting of a carboxyl-modified acrylonitrile-butadiene rubber, a hydrogenated acrylonitrile-butadiene rubber, and a carboxyl-modified hydrogenated acrylonitrile-butadiene rubber.

13. The golf club according to claim 11 , wherein the cylindrical inner layer is a porous rubber layer and the cylindrical outer layer is a solid layer.

14. The golf club according to claim 13 , wherein the porous rubber layer has a foaming ratio ranging from 1.2 to 5.0.

15. The golf club according to claim 11 , wherein the golf club grip is obtained by press molding a laminated product and a grip end in a mold,

wherein the laminated product comprises an unvulcanized rubber sheet formed from the rubber composition containing a carboxyl-modified acrylonitrile-butadiene rubber and/or a carboxyl-modified hydrogenated acrylonitrile-butadiene rubber as a base rubber and an unvulcanized rubber sheet formed from the second rubber composition, and the grip end is formed from the first rubber composition.

16. The golf club according to claim 11 , wherein the cylindrical inner layer is a foamed layer formed from the second rubber composition,

wherein the second rubber composition contains the base rubber and microballoons, and

wherein the amount of the microballoons in the second rubber composition is 5 parts by mass or more, and 20 parts by mass or less, with respect to 100 parts by mass of the base rubber.

17. The golf club according to claim 11 , wherein the rubber composition used for the cylindrical outer layer and the first rubber composition used for the grip end contain the same base rubber.

18. The golf club according to claim 11 , wherein the golf club grip has, at the end part thereof on the tip side, a folded back part formed by folding back the cylindrical outer layer inwardly.

19. The golf club according to claim 18 , wherein a length in the grip axis direction L 4 of the folded back part is 4 mm or more and 30 mm or less.