Golf ball
An object of the present invention is to provide a golf ball exhibiting good shot feeling and excellent resilience. The present invention provides a golf ball comprising a spherical core and one or more cover layers disposed outside the spherical core, wherein at least one layer of the cover layers contains: (A) a base resin containing (a-1) an ionomer resin and having a material hardness of 59 or more in Shore D hardness; and (B) a polyrotaxane having a cyclodextrin with at least a part of hydroxyl groups of the cyclodextrin being modified with a caprolactone chain via —O—C 3 H 6 —O— group, a linear molecule piercing through a cyclic structure of the cyclodextrin, and blocking groups located at both terminals of the linear molecule to prevent disassociation of the cyclodextrin.
1. A golf ball comprising a spherical core and one or more cover layers disposed outside the spherical core, wherein at least one layer of the cover layers contains:
(A) a base resin containing (a-1) an ionomer resin and having a material hardness of 59 or more in Shore D hardness; and
(B) a polyrotaxane having a cyclodextrin with at least a part of hydroxyl groups of the cyclodextrin being modified with a caprolactone chain via —O—C 3 H 6 —O— group, a linear molecule piercing through a cyclic structure of the cyclodextrin, and blocking groups located at both terminals of the linear molecule to prevent disassociation of the cyclodextrin.
2. The golf ball according to claim 1 , wherein (A) the base resin further contains (a-2) a non-ionomer resin.
3. The golf ball according to claim 1 , wherein (B) the polyrotaxane has polyethylene glycol as the linear molecule and an adamantyl group as the blocking group.
4. The golf ball according to claim 1 , wherein the cover layer containing (A) the base resin and (B) the polyrotaxane contains (B) the polyrotaxane in an amount of from 0.1 part by mass to 20 parts by mass with respect to 100 parts by mass of (A) the base resin.
5. The golf ball according to claim 1 , wherein the cover layer containing (A) the base resin and (B) the polyrotaxane has a material hardness of from 55 to 65 in Shore D hardness.
6. The golf ball according to claim 1 , wherein (A) the base resin contains (a-1) the ionomer resin in an amount of 50 mass % or more.
7. The golf ball according to claim 2 , wherein (A) the base resin contains (a-2) the non-ionomer resin in an amount of from 1 mass % to 50 mass %.
8. The golf ball according to claim 2 , wherein a mass ratio ((a-2)/(a-1)) of (a-2) the non-ionomer resin to (a-1) the ionomer resin in (A) the base resin ranges from 1/99 to 50/50.
9. The golf ball according to claim 2 , wherein (a-2) the non-ionomer resin is at least one member selected from the group consisting of a polyamide, a styrene elastomer, a polyolefin elastomer, a polyamide elastomer, a polyester elastomer, a binary copolymer composed of an olefin and an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms, and 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.
10. The golf ball according to claim 1 , wherein a total ratio of (A) the base resin and (B) the polyrotaxane to all the resin components in the cover layer containing (A) the base resin and (B) the polyrotaxane is 60 mass % or more.
11. The golf ball according to claim 1 , wherein (a-1) the ionomer resin is at least one member selected from the group consisting of an ionomer resin consisting of 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; and an ionomer resin consisting of 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.
12. The golf ball according to claim 1 , wherein (A) the base resin has the material hardness of 72 or less in Shore D hardness.
13. The golf ball according to claim 1 , wherein (B) the polyrotaxane has a hydroxyl value of from 10 mg KOH/g to 400 mg KOH/g.
14. The golf ball according to claim 1 , wherein (B) the polyrotaxane has a total molecular weight of from 30,000 to 3,000,000 in a weight average molecular weight.