Golf ball

Abstract

An object of the present disclosure is to provide a golf ball having good shot feeling on iron shots, having excellent controllability due to a short rolling distance, and being slightly affected by the wind due to a low maximum flying height. The present disclosure provides a golf ball 2 comprising a spherical core 4, an intermediate layer 6 and an outermost cover 8, wherein the spherical core 4 is formed from a rubber composition containing a natural rubber and methacrylic acid and/or a metal salt thereof, and a center hardness (H0) of the spherical core 4, hardnesses (H2.5, H5.0, H7.5, H10, H12.5, H15) at points having a radial distance of 2.5 mm, 5.0 mm, 7.5 mm, 10 mm, 12.5 mm and 15 mm from a center of the spherical core 4, and a surface hardness (Hs) of the spherical core 4 satisfy a relationship of H0<H2.5<H5.0<H7.5<H10<H12.5<H15<Hs.

1 . A golf ball comprising a spherical core, an intermediate layer covering the spherical core, and an outermost cover covering the intermediate layer, wherein
 the spherical core is formed from a rubber composition containing a base rubber, a co-crosslinking agent, and a crosslinking initiator,   the base rubber contains a natural rubber,   the co-crosslinking agent contains methacrylic acid and/or a metal salt thereof, and   a center hardness (H0) of the spherical core, a hardness (H 2.5 ) at a point having a radial distance of 2.5 mm from a center of the spherical core, a hardness (H 5.0 ) at a point having a radial distance of 5.0 mm from the center of the spherical core, a hardness (H 7.5 ) at a point having a radial distance of 7.5 mm from the center of the spherical core, a hardness (H 10 ) at a point having a radial distance of 10 mm from the center of the spherical core, a hardness (H 12.5 ) at a point having a radial distance of 12.5 mm from the center of the spherical core, a hardness (H 15 ) at a point having a radial distance of 15 mm from the center of the spherical core, and a surface hardness (Hs) of the spherical core satisfy a relationship of   
       H0<H 2.5 <H 5.0 <H 7.5 <H 10 <H 12.5 <H 15 <Hs. 
     
     
         2 . The golf ball according to  claim 1 , wherein the center hardness (H0), the hardness (H 2.5 ), the hardness (H 5.0 ), the hardness (H 7.5 ), the hardness (H 10 ), the hardness (H 12.5 ), the hardness (H 15 ) and the surface hardness (Hs) satisfy the following relationships of
 H 2.5 −H0<4,   H 5.0 −H 2.5 <4,   H 7.5 −H 5.0 <4,   H 10 −H 7.5 <4,   H 12.5 −H 10 <4,   H 15 −H 12.5 <4, and   Hs−H 15 <4 in Shore C hardness.   
     
     
         3 . The golf ball according to  claim 1 , wherein a hardness difference (Hs−H0) between the surface hardness (Hs) of the spherical core and the center hardness (H0) of the spherical core is 10 or less in Shore C hardness. 
     
     
         4 . The golf ball according to  claim 1 , wherein an amount of the natural rubber ranges from 10 mass % to 90 mass % in 100 mass % of the base rubber. 
     
     
         5 . The golf ball according to  claim 1 , wherein a slab hardness of an intermediate layer composition forming the intermediate layer is greater than a slab hardness of a cover composition forming the outermost cover. 
     
     
         6 . The golf ball according to  claim 1 , wherein a cover composition forming the outermost cover is a resin composition containing a urethane resin as a base resin, and
 a slab hardness of the cover composition forming the outermost cover is 40 or less in Shore D hardness.   
     
     
         7 . The golf ball according to  claim 1 , wherein an intermediate layer composition forming the intermediate layer is a resin composition containing an ionomer resin as a base resin, and
 a slab hardness of the intermediate layer composition forming the intermediate layer is 50 or more in Shore D hardness.   
     
     
         8 . The golf ball according to  claim 1 , wherein the base rubber further contains a polybutadiene rubber. 
     
     
         9 . The golf ball according to  claim 2 , wherein the center hardness (H0), the hardness (H 2.5 ), the hardness (H 5.0 ), the hardness (H 7.5 ), the hardness (H 10 ), the hardness (H 12.5 ), the hardness (H 15 ) and the surface hardness (Hs) satisfy the following relationships of
 0.3≤H 2.5 −H0<4,   0.5≤H 5.0 −H 2.5 <4,   0.5≤H 7.5 −H 5.0 <4,   0.5≤H 10 −H 7.5 <4,   0.5≤H 12.5 −H 10 <4,   0.1≤H 15 −H 12.5 <4, and   0<Hs−H 15 <4 in Shore C hardness.   
     
     
         10 . The golf ball according to  claim 1 , wherein the center hardness (H0) of the spherical core ranges from 55 to 77 in Shore C hardness. 
     
     
         11 . The golf ball according to  claim 1 , wherein the surface hardness (Hs) of the spherical core ranges from 60 to 87 in Shore C hardness. 
     
     
         12 . The golf ball according to  claim 5 , wherein a hardness difference (Hm−Hc) between the slab hardness (Hm) of the intermediate layer composition and the slab hardness (Hc) of the cover composition is more than 0 and 50 or less in Shore D hardness.