Multi-piece solid golf ball

Abstract

In a golf ball having a core, an intermediate layer and a cover, the core is formed of a rubber composition and the intermediate layer and the cover are each formed of a resin composition. The core, the intermediate layer-encased sphere and the ball have respective initial velocities which together satisfy the following two conditions:(initial velocity of ball)<(initial velocity of intermediate layer-encased sphere),0.65≤(initial velocity of intermediate layer-encased sphere)−(initial velocity of core)≤1.15 m/s.Also, letting C and B be the respective deflections in millimeters of the core and the ball when compressed under a specific load, the value of C−B is 1.20 mm or more. This golf ball can achieve a superior distance on shots with a utility club and on shots with irons, and exhibits a good durability to repeated impact and a good controllability in the short game.

1 . A multi-piece solid golf ball comprising a core, an intermediate layer and a cover, wherein the core is formed of a rubber composition, the intermediate layer and the cover are each formed of a resin composition; the core has an initial velocity, the intermediate layer-encased sphere obtained by encasing the core with the intermediate layer has an initial velocity and the ball obtained by encasing the intermediate layer-encased sphere with the cover has an initial velocity which together satisfy the following two conditions:
   (initial velocity of ball)<(initial velocity of intermediate layer-encased sphere),     0.65≤(initial velocity of intermediate layer-encased sphere)−(initial velocity of core)≤1.15 m/s; and
   letting C and B be the respective deflections in millimeters of the core and the ball when compressed under an initial load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf), the value of C−B is 1.20 mm or more.   
     
     
         2 . The golf ball of  claim 1 , wherein the ball satisfies the following condition:
   Shore  C  surface hardness of ball<Shore  C  surface hardness of intermediate layer encased sphere>Shore  C  surface hardness of core.   
     
     
         3 . The golf ball of  claim 1 , wherein the resin composition of the intermediate layer includes a high-acid ionomer resin having an acid content of 16 wt % or more. 
     
     
         4 . The golf ball of  claim 1 , wherein the intermediate layer has a specific gravity of 1.05 or more. 
     
     
         5 . The golf ball of  claim 1 , wherein the intermediate layer includes a granular inorganic filler. 
     
     
         6 . The golf ball of  claim 1 , wherein the cover and the intermediate layer have respective specific gravities with a difference therebetween of not more than 0.15. 
     
     
         7 . The golf ball of  claim 1 , wherein the ball satisfies the following condition:
   thickness of cover<thickness of intermediate layer.   
     
     
         8 . The golf ball of  claim 1 , wherein the core has a diameter of from 36.7 to 40.1 mm. 
     
     
         9 . The golf ball of  claim 1 , wherein the core has a hardness profile in which, letting Cc be the Shore C hardness at a center of the core, Cs be the Shore C hardness at a surface of the core, Cm be the Shore C hardness at a midpoint M between the core center and the core surface, Cm−2, Cm−4 and Cm−6 be the respective Shore C hardnesses at positions 2 mm, 4 mm and 6 mm inward from the midpoint M and Cm+2, Cm+4 and Cm+6 be the respective Shore C hardnesses at positions 2 mm, 4 mm and 6 mm outward from the midpoint M, and defining surface areas A to F as follows
 surface area A: ½×2×(Cm−4−Cm−6) 
 surface area B: ½×2×(Cm−2−Cm−4) 
 surface area C: ½×2×(Cm−Cm−2) 
 surface area D: ½×2×(Cm+2−Cm) 
 surface area E: ½×2×(Cm+4−Cm+2) 
 surface area F: ½×2×(Cm+6−Cm+4), 
 
       the core satisfies the condition:
   (surface area  E +surface area  F )−(surface area  A +surface area  B )≥1.0.
 
 
     
     
         10 . The golf ball of  claim 1 , wherein the ball satisfies the following condition:
   (surface area  D +surface area  E )−(surface area  B +surface area  C )≥1.0.