Lubricating Composition

Abstract

The present invention relates to a lubricating composition containing a dispersant, a corrosion inhibitor and an antioxidant. The invention further provides a method for lubricating a mechanical device with the lubricating composition.

1 . A method for lubricating a mechanical device comprising supplying to the mechanical device an ashless lubricating composition comprising:
 (a) a dispersant;   (b) an antioxidant;   (c) a corrosion inhibitor;   (d) an oil of lubricating viscosity; and   (e) optionally an antiwear agent.   
   
   
       2 . The method of  claim 1 , wherein the mechanical device requires a fluid selected from the group consisting of a working fluid, a hydraulic fluid, a circulating oil, a turbine oil and mixtures thereof. 
   
   
       3 . The method of  claim 1 , wherein the mechanical device is a hydraulic system or a turbine system. 
   
   
       4 . The method of  claim 1 , wherein the dispersant is a borated dispersant. 
   
   
       5 . The method of  claim 1 , wherein the antioxidant comprises (i) a hindered phenol or (ii) an alkylated diphenylamine. 
   
   
       6 . The method of  claim 1 , wherein the corrosion inhibitor comprises (i) a 2,5-bis(alkyl-dithio)-1,3,4-thiadiazole, (ii) a benzotriazole containing a hydrocarbyl substitution on at least one of the following ring positions 4- or 5- or 6- or 7-, or (iii) a benzotriazole containing a hydrocarbyl substitution on at least one of the following ring positions 1- or 2-. 
   
   
       7 . The method of  claim 1 , wherein the lubricating composition further comprises (i) a non-ionic phosphorus compound; (ii) an amine salt of a phosphorus compound; or (iii) an ammonium salt of a phosphorus compound. 
   
   
       8 . The method of  claim 1 , wherein the lubricating composition comprises:
 (a) about 0.01 to about 2 wt % of a dispersant;   (b) about 0.01 to about 2 wt % of an antioxidant;   (c) about 0.0001 wt % to about 0.1 wt % of a corrosion inhibitor;   (d) an oil of lubricating viscosity; and   (e) about 0 wt % to about 5 wt % of an antiwear agent.   
   
   
       9 . The method of  claim 1 , wherein the lubricating composition further comprises about 0.05 wt % to about 1.5 wt % of an antiwear agent. 
   
   
       10 . An ashless lubricating composition comprising:
 (a) a dispersant;   (b) an antioxidant;   (c) a corrosion inhibitor;   (d) an oil of lubricating viscosity; and   (e) optionally an antiwear agent.   
   
   
       11 . The ashless lubricating composition of  claim 10  comprising:
 (a) about 0.01 to about 2 wt % of a dispersant;   (b) about 0.01 to about 2 wt % of an antioxidant;   (c) about 0.0001 wt % to about 0.1 wt % of a corrosion inhibitor;   (d) an oil of lubricating viscosity; and   (e) about 0 wt % to about 5 wt % of an antiwear agent.   
   
   
       12 . The ashless lubricating composition of  claim 11 , wherein the antiwear agent is present at about 0.05 wt % to about 1.5 wt % of the ashless lubricating composition.