Grease composition

Abstract

The grease composition of the present invention comprises at least one base oil selected from a mineral oil and a synthetic oil, and based on the total amount of the grease composition, 2 to 35% by mass of a thickener, 0.05 to 5% by mass of an epoxy compound and 0.1 to 20% by mass of an antiwear additive. The grease of the present invention is good in stability, lubricity and friction characteristics and excellent in long-term reliability even under severe use conditions as compared with conventional grease.

1 . A grease composition comprising:
 at least one base oil selected from a mineral oil and a synthetic oil; and   based on the total amount of the grease composition,   2 to 35% by mass of a thickener;   0.05 to 5% by mass of an epoxy compound; and   0.1 to 20% by mass of an antiwear additive.   
     
     
         2 . The grease composition according to  claim 1 , wherein the epoxy compound is at least one selected from a phenyl glycidyl ether type epoxy compound, an alkyl glycidyl ether type epoxy compound, a glycidyl ester type epoxy compound, an alicyclic epoxy compound, an epoxidized aliphatic monoester and an epoxidized vegetable oil. 
     
     
         3 . The grease composition according to  claim 2 , wherein the epoxy compound is an alkyl glycidyl ether represented by the following formula (1): 
       
         
           
           
               
               
           
         
         wherein R represents a linear or branched alkyl group having 6 to 20 carbon atoms. 
       
     
     
         4 . The grease composition according to  claim 3 , wherein the epoxy compound is at least one selected from octyl glycidyl ether, 2-ethylhexyl glycidyl ether, nonyl glycidyl ether, decyl glycidyl ether, undecyl glycidyl ether and dodecyl glycidyl ether. 
     
     
         5 . The grease composition according to  claim 2 , wherein the antiwear additive is at least one selected from an oxygen-containing compound, a nitrogen-containing compound, an organophosphorus compound, an organosulfur compound, an organomolybdenum compound, an alkaline earth metal compound and an organozinc compound. 
     
     
         6 . The grease composition according to  claim 5 , wherein
 the oxygen-containing compound is at least one selected from an ester, an alcohol, an ether and a carboxylic acid,   the nitrogen-containing compound is at least one selected from an aliphatic amine, an aliphatic amide and an aliphatic imide,   the organophosphorus compound is at least one selected from a phosphoric acid ester, a phosphorous acid ester and an acidic phosphoric acid ester amine salt,   the organosulfur compound is at least one selected from a sulfide compound, and sulfurized fat and oil,   the organomolybdenum compound is at least one selected from molybdenum dithiocarbamate and molybdenum dithiophosphate,   the alkaline earth metal compound is at least one selected from alkaline earth metal sulfonate salt, phenate salt and salicylate salt, and   the organozinc compound is at least one selected from a zinc dialkyl, a zinc dialkyldithiophosphate and a zinc dialkyldithiocarbamate.   
     
     
         7 . The grease composition according to  claim 2 , wherein the antiwear additive is a solid lubricant. 
     
     
         8 . The grease composition according to  claim 7 , wherein the solid lubricant is at least one selected from molybdenum disulfide, graphite, a tetrafluoroethylene resin powder and boron nitride. 
     
     
         9 . The grease composition according to  claim 2 , wherein the synthetic oil type is at least one selected from a hydrocarbon oil, a diester, a polyol ester and a polyalkylene glycol compound. 
     
     
         10 . The grease composition according to  claim 2 , wherein the thickener is at least one selected from lithium soaps, calcium soaps, aluminum soaps and a urea compound. 
     
     
         11 . The grease composition according to  claim 5 , containing, as the antiwear additive, an organomolybdenum compound and an organozinc compound. 
     
     
         12 . The grease composition according to  claim 5 , containing, as the antiwear additive, an organomolybdenum compound, an organozinc compound and an organosulfur compound. 
     
     
         13 . A grease composition comprising:
 at least one base oil selected from a mineral oil and a synthetic oil; and   based on the total amount of the grease composition,   2 to 35% by mass of a thickener;   0.05 to 5% by mass of an epoxy compound; and   0.1 to 20% by mass of an antiwear additive, wherein
 the synthetic oil is at least one selected from a hydrocarbon oil, a diester, a polyol ester and a polyalkylene glycol compound; 
 the thickener is at least one selected from lithium soaps, calcium soaps, aluminum soaps and a urea compound; and 
 the epoxy compound is at least one selected from an alkyl glycidyl ether type epoxy compound, a glycidyl ester type epoxy compound and an alicyclic epoxy compound. 
   
     
     
         14 . The grease composition according to  claim 13 , wherein the antiwear additive is at least one selected from an oxygen-containing compound, a nitrogen-containing compound, an organophosphorus compound, an organosulfur compound, an organomolybdenum compound, an alkaline earth metal compound and an organozinc compound. 
     
     
         15 . The grease composition according to  claim 14 , wherein
 the oxygen-containing compound is at least one selected from an ester, an alcohol, an ether and a carboxylic acid,   the nitrogen-containing compound is at least one selected from an aliphatic amine, an aliphatic amide and an aliphatic imide,   the organophosphorus compound is at least one selected from a phosphoric acid ester, a phosphorous acid ester and an acidic phosphoric acid ester amine salt,   the organosulfur compound is at least one selected from a sulfide compound, and sulfurized fat and oil,   the organomolybdenum compound is at least one selected from molybdenum dithiocarbamate and molybdenum dithiophosphate,   the alkaline earth metal compound is at least one selected from alkaline earth metal sulfonate salt, phenate salt and salicylate salt, and   the organozinc compound is at least one selected from a zinc dialkyl, a zinc dialkyldithiophosphate and a zinc dialkyldithiocarbamate.   
     
     
         16 . The grease composition according to  claim 15 , containing, as the antiwear additive, an organomolybdenum compound and an organozinc compound. 
     
     
         17 . The grease composition according to  claim 15 , containing, as the antiwear additive, an organomolybdenum compound, an organozinc compound and an organosulfur compound.