Lubricant composition

Abstract

A lubricating composition including an ester; a viscosity index improver; and at least one of a sterically hindered sulfur-containing, phosphorus-containing compound, and its salt.

1 . A lubricating composition comprising: 
 an ester;    a viscosity index improver; and    at least one of a sulfur-containing, phosphorus-containing compound and a salt of the sulfur-containing, phosphorus-containing compound.    
     
     
         2 . The composition of  claim 1 , wherein the ester has a viscosity less than or equal to about 2 cSt at 100° C.  
     
     
         3 . The composition of  claim 1 , wherein the ester has the formula RCO 2 R 1 , wherein R comprises an alkyl radical having from about 4 to about 9 carbon atoms and R 1  comprises an alkyl radical having from about 4 to about 15 carbon atoms.  
     
     
         4 . The composition of  claim 1 , wherein the ester comprises at least one of isononyl 2-ethylhexanoate, isooctyl 2-ethylhexanoate, 2-ethylhexyl 2-ethylhexanoate, isononyl heptanoate, isononyl isopentanoate, isooctyl heptanoate, isononyl pentanoate, isooctyl isopentanoate, isooctyl pentanoate, octyl pentanoate, nonyl pentanoate, decyl pentanoate, octyl heptanoate, nonyl heptanoate, decyl heptanoate and mixtures thereof.  
     
     
         5 . The composition of  claim 1 , wherein the viscosity index improver is a polyalphaolefin.  
     
     
         6 . The composition of  claim 5 , wherein the polyalphaolefins has a viscosity of from about 40 to about 1000 cSt at 100° C.  
     
     
         7 . The composition of  claim 1 , wherein the sterically hindered sulfur-containing, phosphorus-containing compound is at least one of a compound of formulae (II) and (V):  
       
         
           
           
               
               
           
         
         wherein n is an integer from 1 to 5; and  
         wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 10 , and R 11  are independently selected from the group consisting of hydrogen, cyano, and hydrocarbyl groups comprising from about 1 to about 30 carbon atoms.  
       
     
     
         8 . The composition of  claim 7 , wherein in formula (II) R 1  and R 2  are methyl and R 3 , R 4 , R 5 , and R 6  are hydrogen.  
     
     
         9 . The composition of  claim 1 , wherein the salt of the sulfur-containing, phosphorus-containing compound is at least one of a compound of formulae (III) and (VI):  
       
         
           
           
               
               
           
         
         wherein n is an integer from 1 to 5; and  
         wherein R 1 , R 2 , R 3 , R 4 , R 6 , R 7 , R 8 , R 9 , R 10 , and R 11  are independently selected from the group consisting of hydrogen, cyano, and hydrocarbyl groups comprising from about 1 to about 30 carbon atoms.  
       
     
     
         10 . The composition of  claim 9 , wherein in formula (III) R 3 , R 4 , R 5 , R 6 , R 7  and R 8  are hydrogen; R 1  and R 2  are methyl; and R 9  is a tertiary C 12-14  alkyl group.  
     
     
         11 . The composition of  claim 9 , wherein in formula (VI) R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7  and R 8  are hydrogen; R 9  is a tertiary C 12-14  alkyl group; and R 10  and R 11  are alkyl groups comprising from about 1 to about 6 carbon atoms.  
     
     
         12 . The composition of  claim 1 , further comprising a synthetic base oil.  
     
     
         13 . The composition of  claim 12 , wherein the synthetic base oil comprises a polyalphaolefins.  
     
     
         14 . The composition of  claim 12 , wherein the viscosity index of the combination of the synthetic base oil, the viscosity index improver, and the ester is about 200 or greater.  
     
     
         15 . The composition of  claim 1 , further comprising a gas-to-liquid base oil.  
     
     
         16 . The composition of  claim 1 , further comprising a boron-containing compound.  
     
     
         17 . The composition of  claim 16 , wherein the boron-containing compound is present in the composition in an amount to provide about 5 ppm to about 500 ppm boron.  
     
     
         18 . The composition of  claim 16 , wherein the boron-containing compound is a borated nitrogen-containing compound.  
     
     
         19 . The composition of  claim 16 , wherein the boron-containing compound is a borated phosphorus-containing compound.  
     
     
         20 . The composition of  claim 1 , further comprising an acid and a nitrogen-containing compound, wherein at least one of the acid and the nitrogen-containing compound is a friction modifier.  
     
     
         21 . The composition of  claim 20 , wherein the acid is a friction modifier chosen from at least one of an organic carboxylic acid, organic phosphorus acid, organic sulfonic acid, inorganic phosphorus acid, and a mixture thereof.  
     
     
         22 . The composition of  claim 21 , wherein the organic phosphorus acid is at least one of dialkyl phosphorus acid, monoalkyl phosphorus acid, dialkyl dithiophosphorus acid, dialkyl thiophosphorus acid, amyl acid phosphate, 2-ethylhexyl acid phosphate, and a mixture thereof.  
     
     
         23 . The composition of  claim 20 , wherein the nitrogen-containing compound is a friction modifier and is a mixture of C 8-16  tertiary primary alkyl amine.  
     
     
         24 . A method of lubricating an automotive gear comprising using as the lubricant the composition of  claim 1 .  
     
     
         25 . A method of improving antiwear protection in an automotive gear comprising placing a composition according to  claim 1  in the automotive gear.  
     
     
         26 . A method of improving fuel efficiency in an automotive gear comprising placing a composition according to  claim 1  in an automotive gear.  
     
     
         27 . A method of lubricating an axle comprising using as the lubricant the composition of  claim 1 .  
     
     
         28 . A method of improving antiwear protection in an axle comprising placing a composition according to  claim 1  in the axle.  
     
     
         29 . A method of improving fuel efficiency in an axle comprising placing a composition according to  claim 1  in the axle.  
     
     
         30 . A method of lubricating a stationary gearbox comprising using as the lubricant the composition of  claim 1 .  
     
     
         31 . A method of improving antiwear protection in a stationary gearbox comprising placing a composition according to  claim 1  in the stationary gearbox.  
     
     
         32 . A method of improving fuel efficiency in a stationary gearbox comprising placing a composition according to  claim 1  in the stationary gearbox.  
     
     
         33 . A method of passing ASTM D5704 comprising lubricating a gear with a composition according to  claim 1 .  
     
     
         34 . A method of passing ASTM D6121 with lubricated and nonlubricated gear sets comprising lubricating a gear with a composition according to  claim 1 .  
     
     
         35 . A method of passing ASTM D6121 with nonlubricated gear sets at least about 325° F. for at least about 16 hours comprising lubricating a gear with a composition according to  claim 1 .  
     
     
         36 . A method of maintaining GL-5 and/or SAE J2360 performance comprising lubricating a gear with a composition according to  claim 1 .  
     
     
         37 . A lubricating composition comprising an ester; a viscosity index improver; and a reaction product of a sulfur-containing compound, a phosphorus-containing compound, and a nitrogen-containing compound.