An object of the present invention is to improve the abrasion-resistance of a golf ball having a polyurethane cover. Another object of the present invention is to enhance the resilience and the shot feeling thereof. The present invention provides a golf ball having a cover, said cover comprising, as a base resin, a thermoplastic polyurethane containing a polycarbonate polyol as a constitutional component, wherein the polycarbonate polyol has, as a repeating constitutional unit, a repeating unit (A) shown in a following Formula (I), and a repeating unit (B) shown in a following Formula (II) and having a different structure from that of (A), and a molar ratio of (A)/(B) is from 30/70 to 70/30. In Formula (I), R 1 is a bivalent residue obtained by removing two hydroxyl groups from a diol having 4 to 6 carbon atoms. In Formula (II), R 2 is a bivalent residue obtained by removing two hydroxyl groups from a diol having 4 to 6 carbon atoms.
1. A golf ball having a core, an intermediate layer covering the core, and a cover covering the intermediate layer, wherein said intermediate layer comprises an ionomer resin and does not include a thermoplastic polyester elastomer, said cover comprises a thermoplastic polyurethane containing a polycarbonate polyol as a constitutional component,
wherein the thermoplastic polyurethane is contained in an amount of 50 parts by mass or more in 100 parts by mass of a resin component of said cover,
the polycarbonate polyol has, as a repeating constitutional unit,
a repeating unit (A) shown in a following Formula (I), and
a repeating unit (B) shown in a following Formula (II) and having a different structure from that of (A),
and a molar ratio of (A)/(B) is from 30/70 to 70/30;
wherein R 1 is a bivalent residue obtained by removing two hydroxyl groups from a diol having 4 carbon atoms;
wherein R 2 is a bivalent residue obtained by removing two hydroxyl groups from a diol having 6 carbon atoms;
wherein the thermoplastic polyurethane has hysteresis loss of 35% or less with respect to the energy applied at the elongation of 80%, when the elongation at break is 100% and the polyurethane cover has a slab hardness of from 20 to less than 30 in Shore D hardness.
2. The golf ball according to claim 1 , wherein the thermoplastic polyurethane has the hysteresis loss of from 5% to 30% with respect to the energy applied at the elongation of 80%, when the elongation at break is 100%.
3. The golf ball according to claim 1 , wherein the thermoplastic polyurethane has the hysteresis loss of from 10% to 25% with respect to the energy applied at the elongation of 80%, when the elongation at break is 100%.
4. The golf ball according to claim 1 , wherein the molar ratio of (A)/(B) is from 40/60 to 60/40.
5. The golf ball according to claim 1 , wherein the thermoplastic polyurethane contains an aromatic polyisocyanate as a constitutional component.
6. A golf ball having a core, an intermediate layer covering the core and an urethane cover covering the intermediate layer, wherein said intermediate layer comprises an ionomer resin and does not include a thermoplastic polyester elastomer, said urethane cover comprises a thermoplastic polyurethane containing a polycarbonate polyol as a constitutional component,
wherein the thermoplastic polyurethane is contained in an amount of 50 parts by mass or more in 100 parts by mass of a resin component of said cover,
the polycarbonate polyol has, as a repeating constitutional unit,
a repeating unit (A) shown in a following Formula (I), and
a repeating unit (B) shown in a following Formula (II) and having a different structure from that of (A),
and a molar ratio of (A)/(B) is from 40/60 to 60/40;
wherein R 1 is a bivalent residue obtained by removing two hydroxyl groups from 1,4-butanediol;
wherein R 2 is a bivalent residue obtained by removing two hydroxyl groups from 1,6-hexanediol;
wherein the thermoplastic polyurethane has hysteresis loss of 35% or less with respect to the energy applied at the elongation of 80%, when the elongation at break is 100% and the polyurethane cover has a slab hardness of from 20 to less than 30 in Shore D hardness.
7. The golf ball according to claim 6 , wherein the golf ball is a three-piece golf ball.
8. The golf ball according to claim 6 , wherein the thermoplastic polyurethane contains an aromatic polyisocyanate as a constitutional component.