Lubricating composition

Abstract

In the field of lubricating compositions, notably lubricant compositions for automobile vehicles, in particular to the field of lubricant compositions for transmissions, for gear boxes or for bridges, there is disclosed a lubricating composition including at least 30% by weight of the composition of at least one monoester, at least one polyalphaolefin oil (PAO) for which the kinematic viscosity measured at 100° C. ranges from 40 to 3,000 mm 2 ·s −1 and at least one polyalphaolefin oil (PAO) for which the kinematic viscosity measured at 100° C. ranges from 1.5 to 10 mm 2 ·s −1 . Also disclosed is the use of this lubricating composition for reducing the fuel consumption of a vehicle equipped with a transmission, notably with a bridge or a gear box, lubricated by this lubricating composition.

1 - 23 . (canceled) 
     
     
         24 . A lubricating composition comprising
 (a) at least 30% by weight of the composition of at least one monoester of formula (I)   
       
         
           
           
               
               
           
         
       
       wherein
 R 1  represents a hydrocarbon group, either saturated or unsaturated, linear or branched, comprising from 14 to 24 carbon atoms; 
 R 2  represents a hydrocarbon group, either saturated or unsaturated, linear or branched, comprising from 2 to 18 carbon atoms; 
 (b) at least one polyalphaolefin oil (PAO) for which the kinematic viscosity measured at 100° C. according to the ASTM D445 standard ranges from 40 to 3,000 mm 2 ·s 1 ; 
 (c) at least one polyalphaolefin oil (PAO) for which the kinematic viscosity measured at 100° C. according to the ASTM D445 standard ranges from 1.5 to 10 mm 2 ·s −1 . 
 
     
     
         25 . The lubricating composition according to  claim 24  comprising from 30 to 70% of the monoester of formula (I) by weight of said composition. 
     
     
         26 . The lubricating composition according to  claim 24  for which R 1  is a saturated group and R 2  is an unsaturated group. 
     
     
         27 . The lubricating composition according to  claim 24  for which R 1  is an unsaturated group and R 2  is a saturated group. 
     
     
         28 . The lubricating composition according to  claim 24  for which R 1  and R 2  are saturated groups. 
     
     
         29 . The lubricating composition according to  claim 24  for which R 1  and R 2  are unsaturated groups. 
     
     
         30 . The lubricating composition according to  claim 24  for which
 R 1  represents a hydrocarbon group, either saturated or unsaturated, linear or branched, comprising from 14 to 20 carbon atoms; or 
 R 2  represents a hydrocarbon group, either saturated or unsaturated, linear or branched, comprising from 3 to 14 carbon atoms; or 
 R 1  is a linear group and R 2  is a branched group; or 
 R 1  is a branched group and R 2  is a linear group; or 
 R 1  and R 2  are linear groups; or 
 R 1  and R 2  are branched groups. 
 
     
     
         31 . The lubricating composition according to  claim 24  for which only R 1 , only R 2  or R 1  and R 2  are selected from among
 a linear saturated group; 
 a branched saturated group comprising from 1 to 5 branched chains; 
 a branched saturated group for which the branched chains comprise from 1 to 5 carbon atoms; 
 a branched saturated group comprising from 1 to 5 branched chains and for which the branched chains comprise from 1 to 5 carbon atoms. 
 
     
     
         32 . The lubricating composition according to  claim 24  for which the monoester is selected from among
 stearates; and 
 oleates. 
 
     
     
         33 . The lubricating composition according to  claim 24  for which the monoester is selected from among alkene monoesters and alkyl monoesters. 
     
     
         34 . The lubricating composition according to  claim 24  for which the kinematic viscosity of the polyalphaolefin oil (b), measured at 100° C. according to the ASTM D445 standard, ranges from 40 to 1,500 mm 2 ·s −1 . 
     
     
         35 . The lubricating composition according to  claim 24  for which the average molecular mass by weight of the polyalphaolefin oil (b) is greater than 2,500 Da. 
     
     
         36 . The lubricating composition according to  claim 24  for which the kinematic viscosity of the polyalphaolefin oil (c), measured at 100° C. according to the ASTM D445 standard, ranges from 1.5 to 10 mm 2 ·s −1 . 
     
     
         37 . The lubricating composition according to  claim 24  for which the average molecular mass by weight of the polyalphaolefin oil (c) is less than 500 Da. 
     
     
         38 . The lubricating composition according to  claim 24  comprising from 5 to 30% by weight of the composition of a polyalphaolefin oil (b). 
     
     
         39 . The lubricating composition according to  claim 24 , comprising from 5 to 70% by weight of the composition of a polyalphaolefin oil (c). 
     
     
         40 . The lubricating composition according to  claim 24  comprising
 one, two or three monoesters (a); or 
 one, two or three polyalphaolefin oils (b); or 
 one, two or three polyalphaolefin oils (c); or comprising a single monoester (a), a single polyalphaolefin oil (b) and a single polyalphaolefin oil (c). 
 
     
     
         41 . The lubricating composition according to  claim 24  also comprising at least one additive. 
     
     
         42 . A method of lubricating a system of gears comprising a step of applying at least one lubricating composition according to  claim 24  to said system of gears. 
     
     
         43 . A method of reducing the fuel consumption of an engine comprising a step of applying at least one lubricating composition according to  claim 24  to the engine. 
     
     
         44 . A method of reducing the fuel consumption of a vehicle equipped with a transmission comprising a step of lubricating said transmission with at least one lubricating composition according to  claim 24 . 
     
     
         45 . A method of reducing the traction coefficient of a transmission oil comprising a step of incorporating at least one lubricating composition according to  claim 24  into said transmission oil. 
     
     
         46 . A method of reduction of the traction coefficient of a lubricating composition comprising at least one heavy PAO (b) and at least one lightweight PAO (c), comprising a step of incorporating at least 30% by weight of a composition of a monoester (a) of formula (I) defined according to  claim 24  into said lubricating composition.