Lubricating oil additive and lubricating oil composition

Abstract

The present invention is directed to a lubricating oil additive containing a reaction product of a succinimide compound and a phosphorus atom-containing compound, and to a lubricating oil composition containing a mineral oil and/or a synthetic base oil, and the above lubricating oil additive.

1 . A lubricating oil additive comprising a reaction product of a succinimide compound and a phosphorus atom-containing compound.  
   
   
       2 . A lubricating oil additive as recited in  claim 1 , wherein the phosphorus atom-containing compound is at least one compound selected from the group consisting of phosphorus sulfide, a phospho sulfurized hydrocarbon compound, a phosphate ester, a phosphite ester and a dithiophosphate ester.  
   
   
       3 . A lubricating oil additive as recited in  claim 2 , wherein the phospho sulfurized hydrocarbon compound has a structure in which two alkyl groups are bonded to a phosphorus atom.  
   
   
       4 . A lubricating oil additive as recited in  claim 2 , wherein the phosphate ester, phosphite ester and dithiophosphate ester are each a diester.  
   
   
       5 . A lubricating oil additive as recited in  claim 2 , wherein the alkyl group introduced into the phosphorus atom-containing hydrocarbon compound is an alkyl group which has 2 to 25 carbon atoms and which may have an ether bond and/or a thioether bond.  
   
   
       6 . A lubricating oil composition characterized by comprising a mineral oil and/or a synthetic base oil, and a lubricating oil additive according to  claim 1 .  
   
   
       7 . A lubricating oil composition as recited in  claim 6 , wherein the composition is used for a transmission having a wet clutch or a wet brake.  
   
   
       8 . A lubricating oil composition as recited in  claim 6 , wherein the composition is an automatic transmission fluid or a continuously variable transmission fluid.