Grease composition and bearing

Abstract

The invention provides a grease composition which contains (a) a base oil, (b) a thickener, (c) a compound having an alkylthiocarbamoyl group, represented by the formula (1), (d) a hindered phenol antioxidant, and (e) a metal deactivator; wherein R 1 , R 2 , R 3 and R 4 are each independently an alkyl group having 1 to 20 carbon groups, and X represents S, S—S, S—CH 2 —S, S—CH 2 CH 2 —S or S—CH 2 CH 2 CH 2 —S.

1 . A grease composition comprising (a) a base oil, (b) a thickener, (c) a compound having an alkylthiocarbamoyl group, represented by the formula (1), (d) a hindered phenol antioxidant, and (e) a metal deactivator; 
       
         
           
           
               
               
           
         
       
       wherein R 1 , R 2 , R 3  and R 4  are each independently an alkyl group having 1 to 20 carbon groups, and X represents S, S—S, S—CH 2 —S, S—CH 2 CH 2 —S or S—CH 2 CH 2 CH 2 —S. 
     
     
         2 . The grease composition of  claim 1 , wherein the hindered phenol antioxidant (d) is 2,6-di-tert-butyl-4-methylphenol. 
     
     
         3 . The grease composition of  claim 1 , wherein the metal deactivator (e) is decamethylenecarboxylic acid disalicyloyl hydrazide. 
     
     
         4 . The grease composition of  claim 1 , wherein the base oil (a) is a mixture of a polyol ester oil and an alkyldiphenyl ether oil. 
     
     
         5 . The grease composition of  claim 1 , wherein the thickener (b) is at least one selected from the group consisting of lithium soaps and lithium complex soaps. 
     
     
         6 . The grease composition of  claim 1 , wherein the base oil (a) is contained in an amount of 50 mass % or more; the thickener (b), in an amount of 1 to 30 mass %; the compound (c) having the alkylthiocarbamoyl group represented by the formula (1), in an amount of 0.1 to 10 mass %; the hindered phenol antioxidant (d), in an amount of 0.1 to 10 mass %; and the metal deactivator (e), in an amount of 0.1 to 10 mass %, with respect to the total mass of the grease composition. 
     
     
         7 . A bearing where the grease composition of  claim 1  is enclosed.