Lubricating oil compositions with antioxidant formation and dissipation control

Abstract

A method for controlling formation and dissipation of at least one oligomeric or polymeric aminic antioxidant in a lubricating oil, during operation of an engine or other mechanical component lubricated with the lubricating oil by using as the lubricating oil a formulated oil. The formulated oil has a composition including a lubricating oil base stock as a major component, and at least one oligomeric or polymeric aminic antioxidant, as a minor component. The at least one oligomeric or polymeric aminic antioxidant is formed over time in situ from at least one monomeric aminic antioxidant during operation of the engine or other mechanical component. The at least one oligomeric or polymeric aminic antioxidant is dissipated over time in the lubricating oil during operation of the engine or other mechanical component. The at least one monomeric aminic antioxidant is present in an amount from greater than 2 to 10 wt. % of the lubricating oil.

1 . A method for controlling formation and dissipation of at least one oligomeric or polymeric aminic antioxidant in a lubricating oil, during operation of an engine or other mechanical component lubricated with the lubricating oil by using as the lubricating oil a formulated oil, said formulated oil having a composition comprising a lubricating oil base stock as a major component; and at least one oligomeric or polymeric aminic antioxidant, as a minor component; wherein the at least one oligomeric or polymeric aminic antioxidant is formed over time in situ from at least one monomeric aminic antioxidant during operation of the engine or other mechanical component; wherein the at least one oligomeric or polymeric aminic antioxidant is dissipated over time in the lubricating oil during operation of the engine or other mechanical component; wherein the lubricating oil base stock is present in an amount from about 1 to about 95 weight percent, based on the total weight of the lubricating oil; and wherein the at least one monomeric aminic antioxidant is present in an amount from greater than about 2 to about 10 weight percent, based on the total weight of the lubricating oil. 
     
     
         2 . The method of  claim 1  wherein, in measurements of the lubricating oil by a Sequence IIIH engine test in accordance with ASTM D8111-17, viscosity control and deposit control are improved using a concentration of the at least one monomeric aminic antioxidant from greater than about 2 to about 10 weight percent, based on the total weight of the lubricating oil, as compared to viscosity control and deposit control achieved using a lower concentration of the at least one monomeric aminic antioxidant. 
     
     
         3 . The method of  claim 1  wherein the at least one monomeric aminic antioxidant comprises at least one unsubstituted or hydrocarbyl-substituted diphenyl amine, at least one unsubstituted or hydrocarbyl-substituted phenyl naphthyl amine, or mixtures thereof. 
     
     
         4 . The method of  claim 1  wherein the at least one oligomeric or polymeric aminic antioxidant is the oligomerization or polymerization reaction product of at least one unsubstituted or hydrocarbyl-substituted diphenyl amine, at least one unsubstituted or hydrocarbyl-substituted phenyl naphthyl amine, or both at least one unsubstituted or hydrocarbyl-substituted diphenylamine and at least one unsubstituted or hydrocarbyl-substituted phenyl naphthylamine. 
     
     
         5 . The method of  claim 1  wherein the at least one oligomeric or polymeric aminic antioxidant comprises: 
       
         
           
           
               
               
           
         
         wherein (A) and (B) each range from zero to 10, provided (A)+(B) is at least 2; R 2  is a styrene or C1 to C30 alkyl, R 3  is a styrene or C1 to C30 alkyl, q and y individually range from 0 to up to the valence of the aryl group to which the respective R groups are attached. 
       
     
     
         6 . The method of  claim 1  wherein the at least one monomeric aminic antioxidant comprises: 
       
         
           
           
               
               
           
         
         wherein R is H, C 4 H 9 , C 8 H 17 , or C 9 H 19 ; and/or 
       
       
         
           
           
               
               
           
         
       
     
     
         7 . The method of  claim 1  wherein the at least one oligomeric or polymeric aminic antioxidant is the oligomerization or polymerization reaction product of 
       
         
           
           
               
               
           
         
         wherein (A) and (B) each range from zero to 10, provided (A)+(B) is at least 2; R 2  is a styrene or C1 to C30 alkyl, R 3  is a styrene or C1 to C30 alkyl, q and y individually range from 0 to up to the valence of the aryl group to which the respective R groups are attached. 
       
     
     
         8 . The method of  claim 7  wherein the at least one oligomeric or polymeric aminic antioxidant is an oligomerization or polymerization reaction product comprising: (A)(A), (A)(B), (B)(B), (A)(A)(B), (A)(A)(A), (A)(B)(A), (B)(B)(B), (B)(B)(A), (A)(A)(A)(A), (A)(A)(B)(B), (A)(A)(A)(B), (B)(B)(B)(B), (B)(B)(B)(A), (A)(A)(A)(A)(A), (A)(B)(A)(B)(A), (A)(B)(B)(B)(A), or mixtures thereof. 
     
     
         9 . The method of  claim 7  wherein the at least one oligomeric or polymeric aminic antioxidant is the oligomerization or polymerization reaction product formed by any combination of: 
       
         
           
           
               
               
           
         
         wherein R is H, C 4 H 9 , C 8 H 17 , or C 9 H 9 ; and/or 
       
       
         
           
           
               
               
           
         
       
     
     
         10 . The method of  claim 1  wherein the at least one oligomeric or polymeric aminic antioxidant is an oligomerization or polymerization reaction product selected from the group consisting of: 
       
         
           
           
               
               
           
         
         wherein R 2  is a styrene or C1 to C30 alkyl, R 3  is a styrene or C1 to C30 alkyl, R 4  is a styrene or C1 to C30 alkyl, p, q and y individually range from 0 to up to the valence of the aryl group to which the respective R groups are attached. 
       
     
     
         11 . The method of  claim 1  wherein the lubricating oil base stock is present in an amount from about 1 to about 80 weight percent, based on the total weight of the lubricating oil. 
     
     
         12 . The method of  claim 1  wherein the at least one monomeric aminic antioxidant is present in an amount from about 4 to about 8 weight percent, based on the total weight of the lubricating oil. 
     
     
         13 . The method of  claim 1  wherein the at least one oligomeric or polymeric aminic antioxidant is present in an amount from about 0.1 to about 5 weight percent, based on the total weight of the lubricating oil. 
     
     
         14 . The method of  claim 1  wherein the formulated oil further comprises one or more of a viscosity modifier, dispersant, detergent, other antioxidant, pour point depressant, corrosion inhibitor, metal deactivator, seal compatibility additive, anti-foam agent, inhibitor, and anti-rust additive. 
     
     
         15 . The method of  claim 14  wherein the other antioxidant comprises at least one aromatic amine antioxidant, at least one phenolic antioxidant, or mixtures thereof. 
     
     
         16 . The method of  claim 1  wherein the at least one oligomeric or polymeric aminic antioxidant is formed over time in situ during a Sequence IIIH engine test in accordance with ASTM D8111-17, or a General Motors Oxidation and Deposit Test (GMOD) in accordance with GMW17043, 2 nd  Edition, May 2016. 
     
     
         17 . The method of  claim 1  wherein the lubricating oil is a passenger vehicle engine oil (PVEO), a commercial vehicle engine oil (CVEO), or a lubricating oil that is subjected to heat and oxidative conditions. 
     
     
         18 . A method for regenerating at least one oligomeric or polymeric aminic antioxidant in a lubricating oil, during operation of an engine or other mechanical component lubricated with the lubricating oil by using as the lubricating oil a formulated oil, said formulated oil having a composition comprising a lubricating oil base stock as a major component; and at least one oligomeric or polymeric aminic antioxidant and at least one monomeric aminic antioxidant, as minor components; wherein the at least one oligomeric or polymeric aminic antioxidant dissipates over time in the lubricating oil during operation of the engine or other mechanical component; wherein the at least one oligomeric or polymeric aminic antioxidant and the at least one monomeric aminic antioxidant react to form over time in situ at least one regenerated oligomeric or polymeric aminic antioxidant during operation of the engine or other mechanical component; wherein the lubricating oil base stock is present in an amount from about 1 to about 95 weight percent, based on the total weight of the lubricating oil; wherein the at least one oligomeric or polymeric aminic antioxidant is present in an amount from greater than about 0.1 to about 10 weight percent, based on the total weight of the lubricating oil; and wherein the at least one monomeric aminic antioxidant is present in an amount from greater than about 2 to about 10 weight percent, based on the total weight of the lubricating oil.