Lubricant compositions for transmissions

Abstract

The present disclosure relates to a lubricating composition including at least one base oil, at least one compound including a dithiocarbamate group, at least one compound including a phosphite group, at least one compound including a dithiophosphate group and at least one compound including a thiadiazole group. The lubricating composition simultaneously exhibits good anti-wear properties, extreme-pressure, a low friction coefficient and good anti-seizing properties. The lubricating composition can be used for lubricating transmissions such as gearboxes, axles, preferably manual gearboxes of motor vehicles.

1 . A lubricating composition comprising:
 at least one base oil;   at least one compound A comprising a dithiocarbamate group;   at least one compound B comprising a phosphite group;   at least one compound C comprising a dithiophosphate group; and   at least one compound D comprising a thiadiazole group;   compound A comprising a dithiocarbamate group being a mixture:   of at least one amine dithiocarbamate of general formula (I) (compound A-1)   
       
         
           
           
               
               
           
         
       
       wherein
 R 1  and R 2  represent independently of each other hydrocarbon-containing groups, optionally substituted, comprising from 1 to 30 carbon atoms; 
 R 3 , R 4  and R 5  represent independently of each other a hydrogen atom or a hydrocarbon-containing group of 1 to 30 carbon atoms, it being understood that at least one of the R 3 , R 4  and R 5  groups is not a hydrogen atom; and 
 of at least one metal dithiocarbamate of general formula (II) (compound A-2), 
 
       
         
           
           
               
               
           
         
       
       wherein R 6  and R 7  represent independently of each other hydrocarbon-containing groups, optionally substituted, comprising from 1 to 30 carbon atoms, M represents a metal cation and n is the valency of this metal cation;
 compound D comprising a thiadiazole group being selected from the group formed by: 
 a compound of Formula (V-a) 
 
       
         
           
           
               
               
           
         
       
       wherein:
 R 27  and R 28 , identical or different, represent independently a hydrogen atom or a linear or branched, saturated or unsaturated, alkyl group, comprising from 1 to 30 carbon atoms; 
 a represents an integer ranging from 1 to 3, 
 b represents an integer ranging from 1 to 3, 
 a compound of Formula (V-b) 
 
       
         
           
           
               
               
           
         
       
       wherein
 R 28  represents a hydrogen atom or a linear or branched, saturated or unsaturated, alkyl group, comprising from 1 to 30 carbon atoms; 
 b represents an integer ranging from 1 to 3; 
 a mixture of at least one compound of Formula (V-a) and at least one compound of Formula (V-b); and
 the ratio by weight (compound comprising a dithiophosphate group: compound comprising a thiadiazole group) ranging from 5:1 to 1:10. 
 
 
     
     
         2 . The lubricating composition according to  claim 1  wherein compound A comprising a dithiocarbamate group is a mixture of:
 at least one amine dithiocarbamate of general formula (I) 
 
       
         
           
           
               
               
           
         
       
       wherein
 R 1  and R 2  represent independently of each other hydrocarbon-containing groups, optionally substituted, comprising from 1 to 30 carbon atoms; 
 R 3 , R 4  and R 5  represent independently of each other a hydrogen atom or a hydrocarbon-containing group of 1 to 30 carbon atoms, it being understood that at least one of the R 3 , R 4  and R 5  groups is not a hydrogen atom; and 
 at least one metal dithiocarbamate of general formula (II-a), 
 
       
         
           
           
               
               
           
         
       
       wherein R 6  and R 7  represent independently of each other linear alkyl hydrocarbon-containing groups. 
     
     
         3 . The lubricating composition according to  claim 2  wherein R 6  and R 7  represent independently of each other linear alkyl groups comprising from 4 to 12 carbon atoms. 
     
     
         4 . The lubricating composition according to  claim 1  comprising from 0.1 to 5% by mass of compounds A comprising a dithiocarbamate group, relative to the total mass of lubricating composition. 
     
     
         5 . The lubricating composition according to  claim 1  comprising from 0.1 to 3% by mass of the mixture of amine dithiocarbamate corresponding to Formula (I) (compound A-1) and metal dithiocarbamate corresponding to Formula (II) (compound A-2) relative to the total mass of the composition. 
     
     
         6 . The lubricating composition  claim 1  wherein compound B comprising a phosphite group is selected from the phosphite monoesters, the phosphite diesters or the phosphite triesters, used alone or in a mixture. 
     
     
         7 . The lubricating composition  claim 1  comprising from 0.1 to 5% by mass of compound B comprising a phosphite group, relative to the total mass of lubricating composition. 
     
     
         8 . The lubricating composition  claim 1  wherein compound C comprising a dithiophosphate group is selected from the group constituted by the ammonium dithiophosphates, amine dithiophosphates, ester dithiophosphates and metal dithiophosphates, used alone or in a mixture. 
     
     
         9 . The lubricating composition  claim 1  comprising from 0.1 to 5% by mass of compound C comprising a dithiophosphate group, relative to the total mass of lubricating composition. 
     
     
         10 . The lubricating composition according to  claim 1  comprising from 0.1 to 5% by mass of compound D comprising a thiadiazole group, relative to the total mass of the lubricating composition. 
     
     
         11 . The lubricating composition according to  claim 1  wherein the ratio by weight (compound C comprising a dithiophosphate group: compound D comprising a thiadiazole group) ranges from 3:1 to 1:8. 
     
     
         12 . The lubricating composition according to  claim 1  also comprising an antioxidant selected from the group formed by the aromatic amines or phenol derivatives. 
     
     
         13 . The lubricating composition according to  claim 1  also comprising a dispersant derived from polyisobutene. 
     
     
         14 . The lubricating composition according to  claim 1  having a kinematic viscosity at 100° C. according to the standard ASTM D445 comprised between 4 and 40 cSt. 
     
     
         15 . A method for lubricating transmissions, comprising bringing the transmissions into contact with a lubricating composition comprising
 at least one base oil;   at least one compound A comprising a dithiocarbamate group;   at least one compound B comprising a phosphite group;   at least one compound C comprising a dithiophosphate group; and   at least one compound D comprising a thiadiazole group;   compound A comprising a dithiocarbamate group being a mixture:   of at least one amine dithiocarbamate of general formula (I) (compound A-1)   
       
         
           
           
               
               
           
         
         wherein
 R 1  and R 2  represent independently of each other hydrocarbon-containing groups, optionally substituted, comprising from 1 to 30 carbon atoms; 
 R 3 , R 4  and R 5  represent independently of each other a hydrogen atom or a hydrocarbon-containing group of 1 to 30 carbon atoms, it being understood that at least one of the R 3 , R 4  and R 5  groups is not a hydrogen atom; and 
 of at least one metal dithiocarbamate of general formula (II) (compound A-2), 
 
       
       
         
           
           
               
               
           
         
       
       wherein R 6  and R 7  represent independently of each other hydrocarbon-containing groups, optionally substituted, comprising from 1 to 30 carbon atoms, M represents a metal cation and n is the valency of this metal cation;
 compound D comprising a thiadiazole group being selected from the group formed by:
 a compound of Formula (V-a) 
 
 
       
         
           
           
               
               
           
         
       
       wherein:
 R 27  and R 28 , identical or different represent independently a hydrogen atom or a linear or branched, saturated or unsaturated, alkyl group, comprising from 1 to 30 carbon atoms; 
 a represents an integer ranging from 1 to 3, 
 b represents an integer ranging from 1 to 3, 
 a compound of Formula (V-b) 
 
       
         
           
           
               
               
           
         
         wherein
 R 28  represents a hydrogen atom or a linear or branched saturated or unsaturated, alkyl group, comprising from 1 to 30 carbon atoms; 
 b represents an integer ranging from 1 to 3; 
 a mixture of at least one compound of Formula (V-a) and at least one compound of Formula (V-b); and 
 the ratio by weight (compound comprising a dithiophosphate group: compound comprising a thiadiazole group) ranging from 5:1 to 1:10. 
 
       
     
     
         16 . A method for reducing the fuel consumption of vehicles, comprising bringing a mechanical part of the vehicle engine into contact with a lubricating composition according to  claim 1 . 
     
     
         17 . (canceled) 
     
     
         18 . A method for improving the anti-wear, extreme-pressure, friction and anti-seizing properties of a lubricating composition, comprising adding at least one compound A comprising a dithiocarbamate group, at least one compound B comprising a phosphite group, at least one compound C comprising a dithiophosphate group and at least one compound D comprising a thiadiazole group into a base oil compound A comprising a dithiocarbamate group being a mixture of:
 at least one amine dithiocarbamate of general formula (I) (compound A-1)   
       
         
           
           
               
               
           
         
         wherein
 R 1  and R 2  represent independently of each other hydrocarbon-containing groups, optionally substituted, comprising from 1 to 30 carbon atoms; 
 R 3 , R 4  and R 5  represent independently of each other a hydrogen atom or a hydrocarbon-containing group of 1 to 30 carbon atoms, it being understood that at least one of the R 3 , R 4  and R 5  groups is not a hydrogen atom; and 
 at least one metal dithiocarbamate of general formula (II) (compound A-2), 
 
       
       
         
           
           
               
               
           
         
       
       wherein R 6  and R 7  represent independently of each other hydrocarbon-containing groups, optionally substituted, comprising from 1 to 30 carbon atoms, M represents a metal cation and n is the valency of this metal cation;
 compound D comprising a thiadiazole group being selected from the group formed by: 
 a compound of Formula (V-a) 
 
       
         
           
           
               
               
           
         
       
       wherein:
 R 27  and R 28 , identical or different, represent independently a hydrogen atom or a linear or branched, saturated or unsaturated, alkyl group, comprising from 1 to 30 carbon atoms; 
 a represents an integer ranging from 1 to 3; 
 b represents an integer ranging from 1 to 3; 
 a compound of Formula (V-b) 
 
       
         
           
           
               
               
           
         
       
       wherein
 R 28  represents a hydrogen atom or a linear or branched, saturated or unsaturated, alkyl group, comprising from 1 to 30 carbon atoms; and 
 b represents an integer ranging from 1 to 3;
 a mixture of at least one compound of Formula (V-a) and at least one compound of Formula (V-b).