Grease composition

Abstract

A grease composition comprising base oil, one or more urea thickeners, (A) in the range of from 0.1 to 5 weight % of tungsten disulphide and (B) in the range of from 0.1 to 5 weight % of one or more of zinc dithiophosphates and/or one or more molybdenum dialkyl dithiocarbamates, based on the total weight of the grease composition.

1 . A grease composition comprising base oil, one or more urea thickeners, (A) in the range of from 0.1 to 5 weight % of tungsten disulphide and (B) in the range of from 0.1 to 5 weight % of one or more zinc dithiophosphates and/or one or more molybdenum dialkyl dithiocarbamates, based on the total weight of the grease composition.  
   
   
       2 . Grease composition according to  claim 1 , wherein said grease composition further comprises (C) one or more molybdenum dithiophosphates.  
   
   
       3 . Grease composition according to  claim 2 , wherein the one or more molybdenum dithiophosphates (C) are present in an amount in the range of from 0.1 to 5 weight %, based on the total weight of the grease composition.  
   
   
       4 . Grease composition according to  claim 1 , wherein said one or more urea thickeners are present in a total amount in the range of from 1 to 25 weight %, based on the total weight of the grease composition.  
   
   
       5 . Grease composition according to  claim 1 , wherein the tungsten disulphide (A) is a powder having an average particle size of less than 10 μm obtained by the Fisher method.  
   
   
       6 . Grease composition according to  claim 1 , wherein the one or more zinc dithiophosphates are selected from compounds of formula (I),  
     
       
         
         
             
             
         
       
     
     wherein R′ indicates primary or secondary alkyl groups or aryl groups, which may be the same or different.  
   
   
       7 . Grease composition according to  claim 1 , wherein the one or more zinc dithiophosphates are selected from zinc diisopropyl dithiophosphate, zinc diisobutyl dithiophosphate, zinc diisodecyl dithiophosphate, zinc mono or di-sec-butyl dithiophosphate, zinc mono or di-sec-pentyl dithiophosphate, zinc mono or di-4-methyl-2-pentyl dithiophosphate, zinc di-para-dodecyl phenol dithiophosphate, zinc di-heptyl phenol dithiophosphate and zinc di-para-nonylphenol dithiophosphate.  
   
   
       8 . Grease composition according to  claim 1 , wherein the one or more molybdenum dithiocarbamates are selected from compounds of formula (II),  
       (R 1 R 2 N—CS—S) 2 Mo 2 O m S n    (II)  
     wherein R 1  and R 2 , respectively, may be independently selected from alkyl groups having a carbon number in the range of from 1 to 24, m is an integer in the range of from 0 to 3, n is an integer in the range of from 1 to 4 and m+n=4.  
   
   
       9 . A method of reducing friction and/or wear in the bearings, gears and/or joints of mechanical devices, wherein said method comprises lubricating said bearings, gears and/or joints with a grease composition according to  claim 1 .  
   
   
       10 . Use of a grease composition according to  claim 1  to lubricate a bearing, a gear and/or a joint.  
   
   
       11 . Grease composition according to  claim 2 , wherein said one or more urea thickeners are present in a total amount in the range of from 1 to 25 weight %, based on the total weight of the grease composition.  
   
   
       12 . Grease composition according to  claim 3 , wherein said one or more urea thickeners are present in a total amount in the range of from 1 to 25 weight %, based on the total weight of the grease composition.  
   
   
       13 . Grease composition according to  claim 2 , wherein the tungsten disulphide (A) is a powder having an average particle size of less than 10 μm obtained by the Fisher method.  
   
   
       14 . Grease composition according to  claim 3 , wherein the tungsten disulphide (A) is a powder having an average particle size of less than 10 μm obtained by the Fisher method.  
   
   
       15 . Grease composition according to  claim 4 , wherein the tungsten disulphide (A) is a powder having an average particle size of less than 10 μm obtained by the Fisher method.  
   
   
       16 . Grease composition according to  claim 2 , wherein the one or more zinc dithiophosphates are selected from compounds of formula (I),  
     
       
         
         
             
             
         
       
     
     wherein R′ indicates primary or secondary alkyl groups or aryl groups, which may be the same or different.  
   
   
       17 . Grease composition according to  claim 3 , wherein the one or more zinc dithiophosphates are selected from compounds of formula (I),  
     
       
         
         
             
             
         
       
     
     wherein R′ indicates primary or secondary alkyl groups or aryl groups, which may be the same or different.  
   
   
       18 . Grease composition according to  claim 4 , wherein the one or more zinc dithiophosphates are selected from compounds of formula (I),  
     
       
         
         
             
             
         
       
     
     wherein R′ indicates primary or secondary alkyl groups or aryl groups, which may be the same or different.  
   
   
       19 . Grease composition according to  claim 5 , wherein the one or more zinc dithiophosphates are selected from compounds of formula (I),  
     
       
         
         
             
             
         
       
     
     wherein R′ indicates primary or secondary alkyl groups or aryl groups, which may be the same or different.  
   
   
       20 . Grease composition according to  claim 2 , wherein the one or more zinc dithiophosphates are selected from zinc diisopropyl dithiophosphate, zinc diisobutyl dithiophosphate, zinc diisodecyl dithiophosphate, zinc mono or di-sec-butyl dithiophosphate, zinc mono or di-sec-pentyl dithiophosphate, zinc mono or di-4-methyl-2-pentyl dithiophosphate, zinc di-para-dodecyl phenol dithiophosphate, zinc di-heptyl phenol dithiophosphate and zinc di-para-nonylphenol dithiophosphate.