Mixtures of friction modifiers to provide good friction performance to transmission fluids

Abstract

Mixtures of friction modifiers provide excellent friction performance to transmission fluids, where the friction modifiers include an N-substituted oxalic acid bisamide or amide-ester containing at least two hydrocarbyl groups of 12 to 22 carbon atoms; and an amide or thioamide represented by R 1 R 2 N—C(X)R 3 where X is O or S, R 1 and R 2 are hydrocarbyl groups of at least 6 carbon atoms, and R 3 is hydroxyalkyl group of 1 to 6 carbon atoms or a condensate thereof.

1 . A composition comprising:
 (a) an oil of lubricating viscosity;   (b) about 0.05 to about 3.0 percent by weight of an N-substituted oxalic acid bisamide or amide-ester containing at least two hydrocarbyl groups of about 12 to about 22 carbon atoms; and   (c) about 0.05 to about 3.0 percent by weight of an amide or thioamide represented by the formula R 1 R 2 N—C(X)R 3  wherein X is O or S, R 1  and R 2  are each independently hydrocarbyl groups of at least about 6 to 24 carbon atoms, and R 3  is hydroxyalkyl group of 1 to about 6 carbon atoms or a group formed by the condensation of said hydroxyalkyl group, through a hydroxyl group thereof, with an acylating agent.   
     
     
         2 . The composition of  claim 1  further comprising (d) about 1 to about 6 percent by weight of a dispersant component, comprising one or more succinimide dispersants, said dispersant component containing about 0.05 to about 1 percent by weight boron and having a TBN (oil free) of about 40 to about 100. 
     
     
         3 . The composition of  claim 1  wherein the N-substituted oxalic acid bisamide or amide ester comprises a bisamide represented by the formula: 
       
         
           
           
               
               
           
         
       
       wherein at least two of R 1 , R 2 , R 3 , and R 4  are independently groups comprising a hydrocarbyl group of about 12 to about 22 carbon atoms and up to two of said groups R 1 , R 2 , R 3 , and R 4  are independently hydrogen or a hydrocarbyl group of 10 or fewer carbon atoms. 
     
     
         4 . The composition of  claim 1  wherein the N-substituted oxalic acid bisamide or amide ester comprises a bisamide represented by the formula 
       
         
           
           
               
               
           
         
       
       wherein each R 1  and R 2  is independently an alkyl group of about 12 to about 18 carbon atoms. 
     
     
         5 . The composition of  claim 1  wherein the N-substituted oxalic acid bisamide or amide-ester comprises an amide-ester represented by the formula: 
       
         
           
           
               
               
           
         
       
       wherein R 1  and R 2  are independently hydrocarbyl groups of about 12 to about 22 carbon atoms and R 10  is a hydrocarbyl group of 1 to about 22 carbon atoms. 
     
     
         6 . The composition of  claim 1  wherein (b) the N-substituted oxalic acid bisamide or amide ester comprises a bisamide represented by the formula 
       
         
           
           
               
               
           
         
       
       wherein each of R 5  and R 7  is independently a hydrocarbyl group of about 12 to about 22 carbon atoms and each of R 6  and R 8  is independently hydrogen or a hydrocarbyl group of 1 to about 22 carbon atoms. 
     
     
         7 . The composition of  claim 1  wherein in (c), the amide or thioamide, each of R 1  and R 2  is independently a 2-ethylhexyl group or a group of about 10 to about 18 carbon atoms. 
     
     
         8 . The composition of  claim 1  wherein in (c), the amide or thioamide, is an amide. 
     
     
         9 . The composition of  claim 1  wherein (c), the amide or thioamide, comprises a substituted nitrogen moiety, R 1 R 2 N—, comprising a di-cocoalkylamine moiety or a (2-ethylhexyl)(hydrogenated tallow)amine moiety and a carboxy moiety, —C(O)R 3 , comprising a glycolic moiety. 
     
     
         10 . The composition of  claim 2  wherein (d), the dispersant component, comprises a first borated succinimide dispersant component having a boron content of about 0.1 to about 1 percent by weight and a TBN (oil-free) of about 50 to about 100; and a second succinimide dispersant component having a boron content of less than about 0.1 percent by weight and a TBN (oil-free) of about 40 to about 80. 
     
     
         11 . The composition of  claim 10  wherein the second succinimide dispersant component is boron-free. 
     
     
         12 . The composition of  claim 2  wherein (d,) the dispersant component, comprises at least one succinimide dispersant that is reacted with at least one of terephthalic acid or an inorganic phosphorus compound or a dimercaptothiadiazole compound. 
     
     
         13 . The composition of  claim 1  further comprising at least one of detergents, antioxidants, corrosion inhibitors, seal swell agents, anti-wear agents, organic borate esters, organic borate salts, anti-foam agents, viscosity improvers, or friction modifiers other than those of component (b) or component (c). 
     
     
         14 . A composition prepared by admixing the components of  claim 1 . 
     
     
         15 . A method for lubricating a device with a lubricated clutch comprising supplying thereto the composition of  claim 1 . 
     
     
         16 . The method of  claim 15  wherein the device comprises an automatic transmission.