Rubber composition, and pneumatic tire using same

Abstract

The invention provides a rubber composition prepared by mixing, per 100 parts by mass of a rubber component comprising at least 50% by mass of a diene-based rubber, from 20 to 150 parts by mass of a filler, and from 0.05 to 30 parts by mass of a compound A which has a specific guanidine structure and has a functional group reactive with the diene-based rubber. The rubber composition improves both a high elastic modulus and a low tan δ. The invention also provides a pneumatic tire using the rubber composition.

1 . A rubber composition prepared by mixing, per 100 parts by mass of a rubber component comprising at least 50% by mass of a diene-based rubber, from 20 to 150 parts by mass of a filler, and from 0.05 to 30 parts by mass of a compound A which has a guanidine structure represented by the following formula (I) and has a functional group reactive with the diene-based rubber. 
       
         
           
           
               
               
           
         
         wherein compound A is at least one selected from the group consisting of bis[2-(2,3-diphenylguadnidino)ethyl] disulfane, bis[2-(2-amino-1H-benzimidazol-1-yl)ethyl] disulfane, bis [2-(2-dimethylamino -1H-benzimidazol-1-yl)ethyl] disulfane, N,N′-di-(1H-benzimidazol-2-yl)-N,N′-dimethyl-2,2′-disulfanediyldiethanamine, N,N′-di-(1H-benzimidazol-2-yl)-2,2′-[disulfanediylbis(ethyleneoxy)]diethanamine, 
       
       
         
           
           
               
               
           
         
       
     
     
         2 . The rubber composition according to  claim 1 , wherein the filler comprises, per 100 parts by mass of the rubber component, from 20 to 70 parts by mass of carbon black and from 0 to 80 parts by mass of an inorganic filler. 
     
     
         3 . The rubber composition according to  claim 1 , wherein the guanidine structure is a structure to form a hetero ring represented by the following formula (II-1) or (II-2): 
       
         
           
           
               
               
           
         
       
     
     
         4 . A compound A which is at least one selected from the group consisting of bis[2-(2,3-diphenylguadnidino)ethyl] disulfane, bis[2-(2-amino-1H-benzimidazol-1-yl)ethyl] disulfane, bis[2-(2-dimethylamino-1H-benzimidazol-1-yl)ethyl] disulfane, N,N′-di-(1H-benzimidazol-2-yl)-N,N′-dimethyl-2,2′-disulfanediyldiethanamine, N,N′-di-(1H-benzimidazol-2-yl)-2,2′-[disulfanediylbis(ethyleneoxy)]diethanamine, 
       
         
           
           
               
               
           
         
       
     
     
         5 . A pneumatic tire comprising the rubber composition of  claim 1 .