Lubricant composition for preventing corrosion and/or tribocorrosion of metalparts in an engine

Abstract

A lubricant composition comprising:at least one base oil; andfrom 0.1% to 30% by weight of a phosphorus ester compound of formula (A):in whichs is 0 or 1; andthe radicals X represent, independently of each other, —OR′ or R′ moieties, where R′ represents hydrogen or a linear or branched hydrocarbon moiety, preferably having from 1 to 36 carbon atoms, with the proviso that:when s is 0, the three X radicals represent —OR′ moieties, andwhen s is 1, at least two of the three X radicals are —OR′ moieties.

1 . A lubricant composition comprising:
 at least one base oil; and   from 0.1% to 30% by weight of a phosphorus ester compound of formula (A):   
       
         
           
           
               
               
           
         
       
       in which 
       s is 0 or 1; and 
       the radicals X represent, independently of each other, —OR′ or R′ moieties, where R′ represents hydrogen or a linear or branched hydrocarbon moiety, with the proviso that: 
       when s is 0, the three X radicals represent —OR′ moieties, and 
       when s is 1, at least two of the three X radicals are —OR′ moieties. 
     
     
         2 . The lubricant composition according to  claim 1 , wherein the compound of formula (A) is a compound of formula (B): 
       
         
           
           
               
               
           
         
         defined as:
 R 1  and R 2 , which may be the same or different, independently represent a linear or branched alkyl moiety comprising from 1 to 36 carbon atoms, or R 1  and R 2 , which may be the same or different, independently represent a linear or branched alkenyl moiety comprising from 2 to 36 carbon atoms; and 
 R 3  represents hydrogen or a hydroxyl moiety. 
 
       
     
     
         3 . The composition according to  claim 1 , further comprising at least one additive selected from detergents, dispersants and mixtures thereof. 
     
     
         4 . The composition according to  claim 3 , wherein:
 the amount of detergent varies from 3% to 40% by weight, based on the total weight of the lubricant composition; and/or   the amount of dispersant varies from 0.01% to 10% by weight, based on the total weight of the lubricant composition.   
     
     
         5 . The composition according to  claim 3 , wherein the detergents are calcium carbonate overbased detergents selected from carboxylates, phenates, sulphonates, salicylates and mixed phenate-sulphonate-salicylate detergents. 
     
     
         6 . The composition according to  claim 1 , wherein the compound of formula (A) corresponds to the compound of formula (I) defined by the following formula: 
       
         
           
           
               
               
           
         
       
     
     
         7 . The composition according to  claim 1 , wherein the compound of formula (A) corresponds to the compound of formula (II) defined by the following formula: 
       
         
           
           
               
               
           
         
       
     
     
         8 . Method for preventing and/or reducing corrosion and/or tribocorrosion of at least one metal part of an engine, comprising the addition in a lubricating composition comprising at least one base oil of a compound of formula (A) as defined in  claim 1 . 
     
     
         9 . Method of preventing and/or reducing corrosion and/or tribocorrosion of at least one metal part of an engine, comprising lubricating said metal part with a lubricating composition according to  claim 1 . 
     
     
         10 . A method of passivating at least one metal part of an engine, comprising at least one step of bringing said metal part into contact with a lubricating composition defined according to  claim 1 .