Lubricant compositions for motor vehicle transmissions

Abstract

The disclosure relates to a lubricant composition including: (a) an organomolybdenum compound, (b) one or more anti-wear and extreme pressure additives chosen from thia(di)azoles, (c) one or more phosphorus-containing or phosphor-sulfur-containing anti-wear and extreme pressure additives chosen from phosphites, phosphates, phosphonates, thiophosphates or thiophosphites, the lubricant composition having a weight content of molybdenum between 90 and 350 ppm. This is used for lubrication of gear boxes.

1 . A lubricant composition comprising:
 (a) an organic molybdenum compound,   (b) one or more anti-wear and extreme pressure additives selected from thia(di)azoles,   (c) one or more phosphorus-containing and/or phosphor-sulfur anti-wear and extreme pressure additives selected from phosphites, phosphates, phosphonates, thiophosphates or thiophosphites;   
       the lubricant composition having a molybdenum mass content comprised between 90 and 180 ppm. 
     
     
         2 . The lubricant composition according to  claim 1  having a molybdenum mass content comprised between 140 and 180 ppm. 
     
     
         3 . The lubricant composition according to  claim 1 , having a phosphorus mass content comprised between 500 and 700 ppm. 
     
     
         4 . The lubricant composition according to  claim 1 , comprising at least one dithiophosphate as compound (c). 
     
     
         5 . The lubricant composition according to  claim 1 , comprising at least one dimercaptothiadiazole as compound (b). 
     
     
         6 . The lubricant composition according to  claim 5 , comprising between 0.35 and 1% by mass of dimercaptothiadiazole. 
     
     
         7 . The lubricant composition according to  claim 1 , comprising, as a compound (a), at least one organic complex of molybdenum, obtained by reaction:
 (i) of a fat of the mono-, di- or tri-glyceride or fatty acid type,   (ii) of an amine source of formula (I):   
       
         
           
           
               
               
           
         
         wherein X1 and X2 are either O or else N, and n and m=1 when X1 or X2 is O and n and m=2 when X1 or X2 is N, 
         (iii) and of a source of molybdenum selected from molybdenum trioxide or molybdates in a sufficient amount in order to provide 0.1 to 20.0% of molybdenum based on the weight of the complex. 
       
     
     
         8 . The lubricant composition according to  claim 7 , wherein the compound (ii) is diethanolamine or 2-(2-aminoethyl)aminoethanol. 
     
     
         9 . The lubricant composition according to  claim 7 , wherein the fat (i) is a mono-, di- or tri-glyceride of fatty acids including from 4 to 28 carbon atoms, or a fatty acid including from 4 to 28 carbon atoms. 
     
     
         10 . The lubricant composition according to  claim 7 , wherein the molybdenum complex (a) comprises at least one of the following compounds, either alone or as a mixture: 
       
         
           
           
               
               
           
         
       
       wherein X1 and X2 are either O or else N, and
 n=1 when X1 is O and m=1 when X2 is O, 
 n=2 when X1 is N and m=2 when X2 is N, 
 
       wherein R1 and R2 are fatty hydrocarbon chains comprising between 3 and 27 carbon atoms. 
     
     
         11 . The lubricant composition according to  claim 7 , wherein the molybdenum complex (a) consists of at least one of the compounds corresponding to the following formula: 
       
         
           
           
               
               
           
         
       
       wherein R1 is a fatty hydrocarbon chain comprising between 3 and 27 carbon atoms. 
     
     
         12 . The lubricant composition according to  claim 7 , wherein the molybdenum complex (a) consists of at least one of the compounds corresponding to the following formula: 
       
         
           
           
               
               
           
         
       
       wherein R1 is a fatty hydrocarbon chain comprising between 3 and 27 carbon atoms. 
     
     
         13 . A method for lubricating gear boxes comprising bringing into contact a composition according to  claim 1  with a gear box. 
     
     
         14 . The method according to  claim 13 , wherein the gear box is a manual gear box. 
     
     
         15 . The lubricant composition according to  claim 1 , wherein the organic molybdenum compound is selected from the group consisting of molybdenum dithiophosphates, molybdenum dithiocarbamante and organic complexes of molybdenum. 
     
     
         16 . The lubricant according to  claim 15 , wherein the organic complex of molybdenum is selected from the group consisting of molybdenum carboxylates, molybdeum esters, molybdenum amides.