Antiwear performance of engine oils with $g(b)-dithiophosphorylated propionic acids

Abstract

The invention relates to an engine oil composition is disclosed that meets FZG CEC IT-84/FVA 2434(A10/16.6R/90) of transportation gear oils, wherein FLS=10, which composition comprises a) An engine oil, b) A β-dithiophosphorylated Propionic Acids; and c) Other customary oil additives, Wherein component b) is about 2.0 to about 8.0% by weight, based on the weight of component a) plus component c).

1 . An engine oil composition that meets FZG CEC IT-84/FVA 2434(A10/16.6R/90) of transportation gear oils, wherein FLS=10, comprising 
 a) An engine oil;    b) At least one compound of the formula                          in which 
 R 1  and R 2  independently of one another are C 3 -C 18 alkyl, C 5 -C 12  cycloalkyl, C 5 -C 6  cycloalkylmethyl, C 9 -C 10 bicycloalkylmethyl, C 9 -C 10 tricycloalkylmethyl, phenyl or C 7 -C 24 alkylphenyl or together are (CH 3 ) 2 C(CH 2 ) 2 ,  
 R 3  is hydrogen or methyl, and, if desired,  
   c) other customary oil additives selected from the group consisting of antioxidants, antifoam additives, metal passivators, rust inhibitors, dispersants, detergents, viscosity index improvers, pourpoint depressants and antiwear additives; and    wherein component b) is about 2.0 to about 8.0% by weight, based on the weight of component a) plus component c):    
     
     
         2 . A composition according to  claim 1 , wherein component b) is about 4.0 to about 6.0% by weight, based on the weight of component a) plus component c).  
     
     
         3 . A composition according to  claim 1 , wherein component b) is about 4.5 to about 5.5% by weight, based on the weight of component a) plus component c).  
     
     
         4 . A composition according to  claim 1 , wherein component b) is about 5.0% by weight, based on the weight of component a) plus component c).  
     
     
         5 . A composition according to  claim 1 , in which R 1  and R 2  independently of one another are C 3 -C 18 alkyl, C 5 -C 6 cycloalkyl or C 7 -C 18 alkylphenyl.  
     
     
         6 . A composition according to  claim 1 , in which the antiwear additives of component c) are selected from the group consisting of amine phosphate additives of the formula  
       
         
           
           
               
               
           
         
       
       wherein R 33  is n-hexyl, R 34  is C 1 -C 14  branched alkyl, and x and y are 1 or 2 where x+y=3.  
     
     
         7 . A method of improving the service properties of engine oils which method comprises adding thereto about 2.0 to about 8.0% by weight, based on the weight of the engine oil plus other customary oil additives, of at least one compound of formula (I) according to  claim 1 , wherein the other customary oil additives are selected from the group consisting of antioxidants, antifoam additives, metal passivators, rust inhibitors, dispersants, detergents, viscosity index improvers, pour point depressants and antiwear additives.