Multi-piece solid golf ball

Abstract

The golf ball includes a core, an intermediate layer, and a cover, in which the core is formed of a rubber composition into a single layer or a plurality of layers, the intermediate layer and the cover are both formed of a single-layer resin composition, and a relationship between an initial velocity of the core, an initial velocity of a sphere (intermediate layer-encased sphere) in which the core is encased with the intermediate layer, and an initial velocity of a sphere (ball) in which the intermediate layer-encased sphere is encased with the cover satisfies the following two conditions: (initial velocity of ball)<(initial velocity of intermediate layer-encased sphere) 0.60≤(initial velocity of intermediate layer-encased sphere)−(initial velocity of core)≤1.00 (m/s). and the specific deflection is 3.00 mm or less, and a specific gravity of the intermediate layer is 1.05 or more.

1 . A multi-piece solid golf ball comprising a core, an intermediate layer, and a cover, the core being formed of a rubber composition into a single layer or a plurality of layers, the intermediate layer and the cover being both formed of a single-layer resin composition, wherein a relationship between an initial velocity of the core, an initial velocity of a sphere (intermediate layer-encased sphere) obtained by encasing the core with the intermediate layer, and an initial velocity of a sphere (ball) obtained by encasing the intermediate layer-encased sphere with the cover satisfies the following two conditions:
   (initial velocity of ball)<(initial velocity of intermediate layer-encased sphere)     0.60≤(initial velocity of intermediate layer-encased sphere)−(initial velocity of core)≤1.00 (m/s)
   and a deflection when the ball is compressed under a final load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf) is 3.00 mm or less, and a specific gravity of the intermediate layer is 1.05 or more.   
     
     
         2 . The multi-piece solid golf ball of  claim 1 , wherein assuming that when each sphere of the core and the ball is compressed under a final load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf) and deflections (mm) are denoted by C (mm) and B (mm) respectively, a value of C-B is 1.45 mm or less. 
     
     
         3 . The multi-piece solid golf ball of  claim 1 , wherein the following condition is satisfied:
   ball surface hardness<surface hardness of intermediate layer-encased sphere>core surface hardness   (where the surface hardness of each sphere means Shore C hardness).   
     
     
         4 . The multi-piece solid golf ball of  claim 1 , wherein the resin composition of the intermediate layer contains a high-acid ionomer resin having an acid content of 16 wt % or more. 
     
     
         5 . The multi-piece solid golf ball of  claim 1 , wherein the intermediate layer contains an inorganic particulate filler. 
     
     
         6 . The multi-piece solid golf ball of  claim 1 , wherein a difference between a specific gravity of the cover and the specific gravity of the intermediate layer is 0.15 or less. 
     
     
         7 . The multi-piece solid golf ball of  claim 1 , wherein the following condition is satisfied:
   cover thickness<intermediate layer thickness.   
     
     
         8 . The multi-piece solid golf ball of  claim 1 , wherein the core has a diameter of 36.7 to 40.1 mm and has a hardness profile in which, letting Cc be a Shore C hardness at the center of the core, Cm be a Shore C hardness at a midpoint M between the center and the surface of the core, Cm−2, Cm−4, and Cm−6 be respective Shore C hardnesses at positions 2 mm, 4 mm, and 6 mm inward from the midpoint M, Cm+2, Cm+4, and Cm+6 be respective Shore C hardnesses at positions 2 mm, 4 mm, and 6 mm outward from the center M, and Cs be a Shore C hardness at the surface of the core, the following surface areas A to F are defined:
   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)
 
 and the following condition is satisfied:
   (surface area  E +surface area  F )−(surface area  A +surface area  B )≥2.0.
 
 
 
     
     
         9 . The multi-piece solid golf ball of  claim 8 , wherein the following condition is satisfied:
   (surface area  D +surface area  E )−(surface area  B +surface area  C )≥2.0.