Aromatic Imides And Esters As Lubricant Additives

Abstract

A composition useful as a lubricant for an automatic transmission comprises an oil of lubricating viscosity and a condensation product of an aromatic polycarboxylic acid or mixtures thereof or a reactive equivalent thereof, having at least two carboxylic groups situated so as to permit formation of a cyclic imide having 5 or 6 atoms in said cyclic structure; with an aliphatic primary amine or alcohol, containing 6 to 60 carbon atoms.

What is claimed is: 
     
         1 . A composition comprising
 (a) an oil of lubricating viscosity and   (b) a condensation product of
 (i) an aromatic polycarboxylic acid or mixtures thereof or a reactive equivalent thereof, having at least two carboxylic groups situated so as to permit formation of a cyclic imide having 5 or 6 atoms in said cyclic structure; with 
 (ii) an aliphatic primary amine or alcohol, containing about 6 to about 80 carbon atoms. 
   
     
     
         2 . The composition of  claim 1  wherein the aliphatic primary amine or alcohol comprises a primary amine containing about 12 to about 60 carbon atoms and further containing a secondary or tertiary amino group or an ether group. 
     
     
         3 . The composition of  claim 1  wherein the condensation product comprises an ester, amide, imide, or imidazoline. 
     
     
         4 . The composition of any one of  claims 1  through  3  wherein the condensation product comprises a cyclic imide. 
     
     
         5 . The composition of any one of  claims 1  through  4  wherein the aromatic polycarboxylic acid or reactive equivalent thereof comprises an aromatic ring substituted by at least one succinic acid group or a reactive equivalent thereof. 
     
     
         6 . The composition of any one of  claims 1  through  4  wherein the aromatic polycarboxylic acid or reactive equivalent thereof comprises an aromatic group with at least 2 carboxylic acid groups, or reactive equivalents thereof, on at least two aromatic carbon atoms. 
     
     
         7 . The composition of  claim 6  wherein the aromatic polycarboxylic acid or reactive equivalent thereof comprises a benzene ring with at least two carboxylic acid groups, or reactive equivalents thereof, on adjacent carbon atoms. 
     
     
         8 . The composition of  claim 6  wherein the aromatic polycarboxylic acid or reactive equivalent thereof comprises a naphthalene structure with two carboxylic acid groups, or reactive equivalents thereof, located in positions 1 and 8 of said naphthalene structure. 
     
     
         9 . The composition of any one of  claims 1  through  8  wherein the condensation product comprises a diimide. 
     
     
         10 . The composition of any one of  claims 1  through  4 , or  6 ,  7 , or  9 , wherein the condensation product comprises a pyromellitic diimide. 
     
     
         11 . The composition of any one of  claims 1  through  10  wherein the aliphatic primary amine is represented by the formula:
   H 2 N—(C n H 2n )—X—R 1  
 
 wherein n is 2 to about 6, 
 X is 0 or N—R 2 , 
 R 1  is an alkyl group of at least about 8 carbon atoms, and 
 R 2  is H or an alkyl group. 
 
     
     
         12 . The composition of any one of  claims 1  through  11  wherein the aliphatic primary amine comprises an N,N-dialkyl-1,3-propanediamine. 
     
     
         13 . The composition of  claim 12  wherein the N,N-dialkyl-1,3-propanediamine comprises N,N-di-(hydrogenated tallow)-1,3-propanediamine, N,N-dicoco-1,3-propanediamine or N,N-diisostearyl-1,3-propanediamine. 
     
     
         14 . The composition of any one of  claims 1  through  4 , or  6 , or  7 , or  9  through  13  wherein the condensation product comprises a material represented by 
       
         
           
           
               
               
           
         
       
       wherein each of R 1  and R 3  is independently an alkyl group of about 8 to about 22 carbon atoms and each of R 2  and R 4  is independently hydrogen or an alkyl group of 1 to about 22 carbon atoms, provided that the total number of carbon atoms in R 1  and R 2  is at least about 13 and the total number of carbon atoms in R 3  and R 4  is at least about 13. 
     
     
         15 . The composition of  claim 14  wherein R 1 , R 2 , R 3 , and R 4  are alkyl groups characteristic of tallowamine, cocoamine, or isostearylamine. 
     
     
         16 . The composition of any one of  claims 1  through  15  wherein the amount of the condensation product is about 0.0001 to about 10 weight percent. 
     
     
         17 . The composition of any one of  claims 1  through  16  further comprising at least one further additive selected from the group consisting of dispersants, viscosity modifiers, supplemental friction modifiers, detergents, antioxidants, seal swell agents, and anti-wear agents. 
     
     
         18 . The composition of any of  claims 1  through  16  further comprising at least one additive selected from the group consisting of organic borate esters, organic borate salts, organic phosphorus esters, organic phosphorus salts, inorganic phosphorus salts, and inorganic phosphorus acids. 
     
     
         19 . A method for lubricating a mechanical device, comprising supplying thereto the composition of any one of  claims 1  through  18 . 
     
     
         20 . The method of  claim 19  wherein the mechanical device comprises a transmission. 
     
     
         21 . The method of  claim 19  or  claim 20  wherein the mechanical device comprises an automatic transmission. 
     
     
         22 . The method of  claim 19  wherein the mechanical device comprises an internal combustion engine.