Lubricating oil additive and lubricating oil composition containing the same

Abstract

The present invention provides a lubricating oil additive with excellent cleaning performance which does not include metal components such as calcium or magnesium, and a lubricating oil composition containing the same. The lubricating oil additive according to the present invention is characterized by containing a quaternary ammonium salt having a base number of at least 10 mgKOH/g. Examples of such a quaternary ammonium salt include quaternary ammonium salts obtained by subjecting counter anions in cationic surfactants such as tetraalkylammonium chloride and tetraalkylammonium sulfate to salt-exchange.

1 . A lubricating oil additive comprising a quaternary ammonium salt having a base number of at least 10 mgKOH/g.  
   
   
       2 . A lubricating oil additive according to  claim 1 , wherein the quaternary ammonium salt is represented by the following general formula (1)  
     
       
         
         
             
             
         
       
       where R 1  to R 4  each independently represent a hydrocarbon group having 1 to 30 carbon atoms, —R 9 O—CO—R 10 , or —R 11 NH—CO—R 12  (provided that at least one of R 1  to R 4  represents a hydrocarbon group having 1 to 30 carbon atoms), R 9  and R 11  each represent a hydrocarbon group having 1 to 4 carbon atoms, R 10  and R 12  each represent a hydrocarbon group having 1 to 30 carbon atoms or a hydrogen atom, and X −  represents an anionic group.  
     
   
   
       3 . A lubricating oil additive according to  claim 1 , wherein X is selected from the group consisting of anionic groups derived from carbonic acid, a carbonate, boric acid and an organic carboxylic acid, and a hydroxyl group.  
   
   
       4 . A lubricating oil additive according to  claim 1 , which is used for internal combustion engine lubricating oil or for driving system lubricating oil.  
   
   
       5 . A lubricating oil composition comprising 0.1 to 10% by mass of the lubricating oil additive according to  claim 1  based on a base oil.  
   
   
       6 . A lubricating oil additive according to  claim 2 , wherein X is selected from the group consisting of anionic groups derived from carbonic acid, a carbonate, boric acid and an organic carboxylic acid, and a hydroxyl group.  
   
   
       7 . A lubricating oil additive according to  claim 2 , which is used for internal combustion engine lubricating oil or for driving system lubricating oil.  
   
   
       8 . A lubricating oil additive according to  claim 3 , which is used for internal combustion engine lubricating oil or for driving system lubricating oil.  
   
   
       9 . A lubricating oil additive according to  claim 6  which is used for internal combustion engine lubricating oil or for driving system lubricating oil.  
   
   
       10 . A lubricating oil composition comprising 0.1 to 10% by mass of the lubricating oil additive according to  claim 2  based on a base oil.  
   
   
       11 . A lubricating oil composition comprising 0.1 to 10% by mass of the lubricating oil additive according to  claim 3  based on a base oil.  
   
   
       12 . A lubricating oil composition comprising 0.1 to 10% by mass of the lubricating oil additive according to  claim 4  based on a base oil.  
   
   
       13 . A lubricating oil composition comprising 0.1 to 10% by mass of the lubricating oil additive according to  claim 6  based on a base oil.