One-piece solid golf ball

Abstract

The present invention provides a one-piece solid golf ball having excellent rebound characteristics and good shot feel, while maintaining excellent processability and durability. The present invention relates to a one-piece solid golf ball formed from a rubber composition comprising a mixture consisting of polybutadiene (a) synthesized using nickel-containing catalyst and polybutadiene (b) synthesized using cobalt-containing catalyst and hydroquinone or derivatives thereof as a vulcanization stabilizer, wherein a Mooney viscosity and a weight ratio of the polybutadienes (a) and (b), an amount of the vulcanization stabilizer, a center hardness (the minimum hardness in the golf ball) and surface hardness of the golf ball, and a difference between the maximum hardness and minimum hardness in the golf ball are adjusted to a specified range.

What is claimed is:  
     
         1 . A one-piece solid golf ball formed from a rubber composition comprising a base rubber, a co-crosslinking agent, an organic peroxide, an inorganic filler and a vulcanization stabilizer, and the base rubber comprises a polybutadiene mixture consisting of 
 (i) a polybutadiene (a) containing a cis-1,4 bond of not less than 96% and having a Mooney viscosity of 50 to 85 ML 1+4 (100° C.) and a weight average molecular weight (Mw) of 70×10 4  to 120×10 4 , synthesized using nickel-containing catalyst, and    (ii) a polybutadiene (b) containing a cis-1,4 bond of not less than 96% and having a Mooney viscosity of 30 to 50 ML 1+4 (100° C.) and a weight average molecular weight (Mw) of not less than 55×10 4  and less than 70×10 4 , synthesized using cobalt-containing catalyst, a weight ratio (a)/(b) being 95/5 to 70/30, wherein    the vulcanization stabilizer is selected from the group consisting of hydroquinone and derivatives thereof, and an amount of the vulcanization stabilizer is 0.05 to 20 parts by weight, based on 100 parts by weight of the base rubber, and    the golf ball has a center hardness in JIS-C hardness of 55 to 68 and a surface hardness in JIS-C hardness of 75 to 90, the center hardness is the minimum hardness in the golf ball, and a difference between the maximum hardness and minimum hardness in the golf ball is within the range of 16 to 25.    
     
     
         2 . The one-piece solid golf ball according to  claim 1 , wherein the vulcanization stabilizer is 2,5-di-t-butylhydroquinone.  
     
     
         3 . The one-piece solid golf ball according to  claim 1 , wherein the polybutadiene (b) synthesized using cobalt-containing catalyst has a ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) of 3.0 to 5.0