Solid golf ball
View Patent ↗A solid golf ball with a polyurethane cover having satisfactory formability and ball properties. The solid golf ball has a solid core, and a polyurethane cover for covering the solid core, wherein the difference in Shore D hardness between a center portion and a surface portion of the solid core is at least 15; the polyurethane cover has a thickness (t) of not more than 1.0 mm, and is formed from a cured urethane composition having Shore D hardness (D) of from 35 to 60; a product of the thickness(t) and the Shore D Hardness (D) of the cured urethane composition is ranging from 10 to 45(10≦D×t≦45); and the urethane composition contains an isocyanate group-terminated urethane prepolymer having the residual polyisocyanate monomer content of not more than 0.1 mass %, and an aromatic polyamine compound.
1. A solid golf ball comprising
a solid core, and a polyurethane cover for covering the solid core, wherein
the difference in Shore D hardness between a center portion and a surface portion of the solid core is at least 15 and the deformation amount of the core is 2.60 to 3.00 mm when applying a load from 98N as an initial load to 1275N as a final load to the solid core;
the polyurethane cover has a thickness (t) of not more than 1.0 mm, and is formed from a cured urethane composition having Shore D hardness (D) of from 35 to 60;
a product of the thickness(t) and the Shore D Hardness (D) of the cured urethane composition is ranging from 10 to 45(10≦D×t≦45) ; and
the urethane composition comprises an isocyanate group-terminated urethane prepolymer having the residual polyisocyanate monomer content of not more than 0.1 mass %, and an aromatic polyamine compound.
2. The solid golf ball according to claim 1 , wherein the aromatic polyamine compound is a 4,4′-diaminodiphenylmethane represented by the following general formula or a derivative thereof.
(where R 1 to R 8 are each independently an alky group having 1 to 9 carbon atoms, halogen atom, or hydrogen atom).
3. The solid golf ball according to claim 2 , wherein the aromatic polyamine compound is 2,2′-dichloro-3,3′,5,5′-tetraethyl-4,4′-diaminodiphenylmethane.
4. The solid golf ball according to claim 1 , wherein the isocyanate group-terminated urethane prepolymer is at least one selected from the group consisting of a TDI polyurethane prepolymer, a MDI polyurethane prepolymer, and a hydrogenated MDI urethane prepolymer.
5. The solid golf ball according to claim 1 , wherein the deformation is 2.50 to 3.20 mm when applying a load from 98N as a initial load to 1275N as a final load to the solid golf ball.
6. The solid golf ball according to claim 1 , wherein the solid core has a diameter of from 40.8 mm to 42.2 mm.
7. The solid golf ball according to claim 1 , wherein the product of the thickness (t) and the Shore D Hardness (D) of the cured urethane composition is ranging from 21 to 38(21≦D×t≦38).
8. The solid golf ball according to claim 1 , wherein the solid golf ball is a two-piece golf ball.
9. The solid golf ball according to claim 1 , wherein the difference in Shore D hardness between the center portion and the surface portion of the solid core is within the range from 20 to 28.
10. The solid golf ball according to claim 1 , wherein the cured urethane composition has Shore D hardness (D) of from 42 to 55.