Multi-piece solid golf ball
In a multi-piece solid golf ball having a core, an intermediate layer encasing the core and a cover which encases the intermediate layer and has numerous dimples on an outside surface thereof, the intermediate layer is formed of a resin material comprising an ionomer resin as a base resin and an inorganic granular filler, the cover is formed of a urethane resin material, the core has a diameter of at least 38.0 mm, the core has specific deflection, the sphere obtained by encasing the core with the intermediate layer (intermediate layer-encased sphere) has a surface hardness on the Shore D hardness scale of at least 69, the ball has a surface hardness on the Shore D hardness scale of 62 or less, and the (intermediate layer thickness)/(core diameter) value is from 0.025 to 0.043, the (cover thickness)/(core diameter) value is from 0.014 to 0.027.
1 . A multi-piece solid golf ball comprising a core, an intermediate layer encasing the core and a cover which encases the intermediate layer and has numerous dimples formed on an outside surface thereof (ball surface), wherein the core is formed of the rubber composition, the intermediate layer is formed of a resin material comprising an ionomer resin as a base resin and an inorganic granular filler, the cover is formed of a urethane resin material, the core has a diameter of at least 38.0 mm, the core has a deflection when compressed under a final load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf) of at least 3.9 mm, a sphere obtained by encasing the core with the intermediate layer (intermediate layer-encased sphere) has a surface hardness on the Shore D hardness scale of at least 69, the ball has a surface hardness on the Shore D hardness scale of 62 or less, the (intermediate layer thickness)/(core diameter) value is from 0.025 to 0.043, the (cover thickness)/(core diameter) value is from 0.014 to 0.027, and the intermediate layer has a specific gravity which is 1.05 or more.
2 . The multi-piece solid golf ball of claim 1 , wherein the core is formed of a rubber composition that includes compounding ingredients (I) to (IV),
(I) a base rubber
(II) an organic peroxide
(III) water and/or a metal monocarboxylate, and
(IV) sulfur.
3 . The multi-piece solid golf ball of claim 2 , wherein the weight ratio between pure sulfur component of component (IV) and component (III), expressed as (IV)/(III) value, is from 0.010 to 0.200.
4 . The multi-piece solid golf ball of claim 1 , wherein the core has a center and a surface such that the value obtained by subtracting the JIS-C hardness at the core center from the JIS-C hardness at the core surface is at least 15.
5 . The multi-piece solid golf ball of claim 1 , wherein the intermediate layer-encased sphere has an initial velocity A and the core has an initial velocity B which together satisfy the condition A−B≥0 m/s.
6 . The multi-piece solid golf ball of claim 1 , wherein the (intermediate layer thickness)/(core diameter) value is from 0.028 to 0.041 and the (cover thickness)/(core diameter) value is from 0.017 to 0.024.
7 . The multi-piece solid golf ball of claim 1 , wherein the value obtained by subtracting the Shore D hardness at a surface of the core from the Shore D hardness at a surface of the intermediate layer-encased sphere is at least 6, the value obtained by subtracting the Shore D hardness at the surface of the intermediate layer-encased sphere from the Shore D hardness at the ball surface is 0 or less, and the value obtained by subtracting the Shore D hardness at the ball surface from the Shore D hardness at the core surface is-5 or more.
8 . The multi-piece solid golf ball of claim 1 , wherein the initial velocities of the core, the intermediate layer-encased sphere and the ball satisfy the following relationship:
initial velocity of intermediate layer-encased sphere>initial velocity of core>initial velocity of ball.
9 . The multi-piece solid golf ball of claim 1 , wherein the core has a hardness profile from a center to a surface thereof which satisfies the following condition:
5≤(JIS-C hardness at core surface-JIS-C hardness 5 mm inside of core surface)−(JISC hardness 5 mm outside of core center-JIS-C hardness at core center)≤13.
10 . A multi-piece solid golf ball comprising a core, an intermediate layer encasing the core and a cover which encases the intermediate layer and has numerous dimples formed on an outside surface thereof (ball surface), wherein the core is formed of the rubber composition, the intermediate layer is formed of a resin material, the cover is formed of a urethane resin material, the core has a diameter of at least 38.0 mm, the core has a deflection when compressed under a final load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf) of at least 3.9 mm, the intermediate layer has a specific gravity which is 1.05 or more, a sphere obtained by encasing the core with the intermediate layer (intermediate layer-encased sphere) has a surface hardness on the Shore D hardness scale of at least 69, the ball has a surface hardness on the Shore D hardness scale of 62 or less, and the (intermediate layer thickness)/(core diameter) value is from 0.025 to 0.043, the (cover thickness)/(core diameter) value is from 0.014 to 0.027.
11 . The multi-piece solid golf ball of claim 10 , wherein the resin material of the intermediate layer comprises an ionomer resin as a base resin and an inorganic granular filler.
12 . The multi-piece solid golf ball of claim 10 , wherein the core is formed of a rubber composition that includes compounding ingredients (I) to (III),
(I) a base rubber
(II) an organic peroxide, and
(III) water and/or a metal monocarboxylate.
13 . The multi-piece solid golf ball of claim 12 , wherein the rubber composition for the core further include (IV) sulfur, and the weight ratio between pure sulfur component of component (IV) and component (III), expressed as (IV)/(III) value, is from 0.010 to 0.200.
14 . The multi-piece solid golf ball of claim 10 , wherein the core has a center and a surface such that the value obtained by subtracting the JIS-C hardness at the core center from the JIS-C hardness at the core surface is at least 15.
15 . The multi-piece solid golf ball of claim 10 , wherein the intermediate layer-encased sphere has an initial velocity A and the core has an initial velocity B which together satisfy the condition A−B≥0 m/s.