Lubricants with improved seal compatibility

Abstract

The present invention relates to lubricating compositions and particularly gear oil compositions that include a specific class of substituted triazoles, where the substituted triazole includes at least one hydrocarbyl group linked to one of the nitrogen atoms in the triazole ring. Such compositions provide surprisingly good seal compatibility compared to compositions with other triazoles and/or alternative additives.

1 . An industrial gear lubricating composition comprising (i) an oil of lubricating viscosity and (ii) a substituted triazole;
 where the substituted triazole includes at least one hydrocarbyl group linked to one of the nitrogen atoms in the triazole ring.   
     
     
         2 . The composition of  claim 1  wherein the substituted triazole is present in the lubricating composition from 0.05 to 1.0 percent by weight. 
     
     
         3 . The composition of  claim 1  wherein the hydrocarbyl group of the substituted triazole contains from 6 to 40 carbon atoms. 
     
     
         4 . The composition of  claim 1  wherein the hydrocarbyl group of the substituted triazole includes at least one nitrogen atom. 
     
     
         5 . The composition of  claim 1  wherein the hydrocarbyl group of the substituted triazole includes at least one nitrogen atom and is branched. 
     
     
         6 . The composition of  claim 1  wherein the substituted triazole comprises a compound having the formula: 
       
         
           
           
               
               
           
         
       
       or the formula: 
       
         
           
           
               
               
           
         
       
       or a combination thereof; where, for both formula I and formula II:
 n is an integer from 0 to 4; 
 —R is a hydrocarbyl group; 
 —Y is —R 1  or —(R 2 ) m —NR 3 R 3  where
 —R 1  is a hydrocarbyl group containing from 6 to 40 carbon atoms, 
 —R 2 — is a hydrocarbylene group, m is 0 or 1, and 
 each —R 3  is independently hydrogen or a hydrocarbyl group, 
 so long as the sum of carbon atoms in the —R 2  group and both —R 3  groups is from 7 to 40 combined. 
 
 
     
     
         7 . The composition of  claim 6  wherein Y is —R 2 —NR 3 R 3  and where —R 2 — is a hydrocarbylene group containing 1 to 2 carbon atoms, and both —R 3  groups are branched alkyl groups containing 6 to 20 carbon atoms. 
     
     
         8 . The composition of  claim 6  wherein the substituted triazole comprises a compound represented by formula (I). 
     
     
         9 . The composition of  claim 6  wherein the substituted triazole comprises a compound represented by formula (II). 
     
     
         10 . The composition of  claim 1  wherein the oil of lubricating viscosity comprises a mineral base oil. 
     
     
         11 . The composition of  claim 1  wherein the oil of lubricating viscosity comprises a synthetic base oil. 
     
     
         12 . The composition of  claim 1  further comprising: an antiwear agent, an extreme pressure agent, a friction modifier, a corrosion inhibitor, a rust inhibitor, a metal deactivator, a borated dispersant, a non-borated dispersants, detergent, an antifoam, a viscosity index improver, a viscosity modifier, an additional antioxidant, a pour point depressant, a seal swell agent, or any combination thereof. 
     
     
         13 . The composition of  claim 1  wherein the substituted triazole comprises the reaction product of a triazole, an aldehyde and an amine. 
     
     
         14 . A method of lubricating a gear assembly comprising supplying to said assembly a lubricating composition comprising (i) an oil of lubricating viscosity and (ii) a substituted triazole;
 where the triazole includes at least one hydrocarbyl group linked to one of the nitrogen atoms in the triazole ring.   
     
     
         15 . The method of  claim 14  wherein the oil of lubricating viscosity comprises a mineral base oil. 
     
     
         16 . The method of  claim 14  wherein the oil of lubricating viscosity comprises a synthetic base oil. 
     
     
         17 . The method of  claim 14  wherein the substituted triazole comprises a compound having the formula: 
       
         
           
           
               
               
           
         
       
       or the formula: 
       
         
           
           
               
               
           
         
       
       or a combination thereof; where, for both formula I and formula II:
 n is an integer from 0 to 4; 
 —R is a hydrocarbyl group; 
 —Y is —R 1  or —(R 2 ) m —NR 3 R 3  where
 —R 1  is a hydrocarbyl group containing from 6 to 40 carbon atoms, 
 —R 2 — is a hydrocarbylene group, m is 0 or 1, and 
 each —R 3  is independently hydrogen or a hydrocarbyl group, 
 so long as the sum of carbon atoms in —R 2  and —R 3  is from 7 to 40 combined. 
 
 
     
     
         18 . The method of  claim 14  wherein the substituted triazole comprises the reaction product of a triazole, an aldehyde and an amine.