Lubricating Compositions Containing Sulphonates and Phenates

Abstract

A lubricating composition containing (a). at least 3 weight percent of an overbased sulphonate detergent with a metal ratio of 12.5:1 to 40:1; (b). at least 1.5 weight percent of a sulphur containing phenate detergent with a metal ratio of not more 2.5; and (c). an oil of lubricating viscosity, wherein the sulphur containing phenate contains oligomers of hydrocarbyl phenol with at least 50 wt % of said oligomers in the form of the tetramer or higher oligomers. The composition is suitable for internal combustion engines, particularly marine diesel applications to provide improved cleanliness decreased cylinder wear and reduced deposits.

1 . A composition comprising:
 (a). at least about 3 weight percent of an overbased sulphonate detergent with a metal ratio of about 12.5:1 to about 40:1;   (b). at least about 1.5 weight percent of a sulphur containing phenate detergent with a metal ratio of not more than about 3;   (c). an oil of lubricating viscosity; and   (d). an antiwear agent selected from the group consisting of salixarates, fatty amides, amine salts of phosphoric acid esters, thiocarbamate esters, thiocarbamates amides, thiocarbamic ethers, alkylene-coupled thiocarbamates, bis(S-alkyldithocarbamyl)disulfides, monoesters of polyols and aliphatic carboxylic acids, and borate esters,   
       wherein the sulphur containing phenate contains oligomers of hydrocarbyl phenol with at least about 50 wt % of said oligomers in the form of the tetramer or higher oligomers. 
     
     
         2 . The composition of  claim 1 , wherein the antiwear agent contains an atom of sulphur, phosphorus, boron or mixtures thereof. 
     
     
         3 . The composition of  claim 2 , wherein the antiwear agent is a sulphur-containing thiocarbamate. 
     
     
         4 . The composition of  claim 3 , wherein the thiocarbamate is selected from the group consisting of thiocarbamate esters, thiocarbamate amides, thiocarbamic ethers, alkylene-coupled thiocarbamates, and bis(S-alkyldithiocarbamyl) disulfides. 
     
     
         5 . The composition of  claim 1 , wherein the antiwear agent comprises a monoester of a polyol and an aliphatic carboxylic acid. 
     
     
         6 . The composition of  claim 5 , wherein the antiwear agent comprises glycerol monooleate. 
     
     
         7 . The composition of  claim 1  wherein the antiwear agent is an ashless antiwear agent. 
     
     
         8 . The composition of  claim 1 , wherein the sulphonate detergent has a total base number of at least about 400. 
     
     
         9 . The composition of  claim 1 , wherein the sulphur containing phenate detergent is represented by the formula: 
       
         
           
           
               
               
           
         
       
       wherein the number of sulphur atoms y is 1 to about 8; T is hydrogen or an (S) y  linkage terminating in hydrogen, an ion or a non-phenolic hydrocarbyl group sulphur; M is hydrogen, a valence of a metal ion, an ammonium ion and mixtures thereof, provided hydrogen is present on less than about 30% of the M entities; and R 2  is hydrogen or hydrocarbyl groups containing about 4 to about 80 carbon atoms; x is 0 to about 10, provided that at least about 50% of x is about 2 or higher; w, is in the range from 0 to about 3, provided that at least one aromatic ring contains an R 2  substituent and the total number of carbon atoms in the R 2  groups is at least about 8. 
     
     
         10 . The composition of  claim 1 , wherein the sulphur containing phenate detergent contains less than about 20 wt % dimeric structures. 
     
     
         11 . The composition of  claim 1 , wherein the sulphur containing phenate detergent contains a substrate level excluding metal M and any carbonate of M in the range about 45 to about 95 wt % of the sulphur containing phenate detergent. 
     
     
         12 . The composition of  claim 1 , wherein the sulphur containing phenate detergent has a total base number between about 30 to about 220. 
     
     
         13 . The composition of  claim 1  further comprising a borated dispersant. 
     
     
         14 . A method for lubricating an internal combustion engine, comprising supplying thereto a lubricant comprising the composition of  claim 1 . 
     
     
         15 . The method of  claim 14 , wherein the internal combustion engine is a marine diesel engine. 
     
     
         16 . The method of  claim 15 , wherein the internal combustion engine is 2-stroke engine.