Lubricating Composition Containing an Ester

Abstract

The invention relates to a method of lubricating a limited slip differential comprising supplying to the limited slip differential a lubricating composition containing (a) an oil of lubricating viscosity, and (b) a C4-30-diester of a dicarboxylic acid. The invention further provides for the use of the C4-30-diester of a dicarboxylic acid as a friction modifier, typically in a limited slip differential.

1 - 23 . (canceled) 
     
     
         24 . A method of lubricating a limited slip differential comprising supplying to the limited slip differential a lubricating composition comprising (a) an oil of lubricating viscosity, and (b) a C 4-30 -diester of adipic acid, wherein the C 4-30 -diester of adipic acid is present at 0.01 wt % to less than 1 wt % of the lubricating composition. 
     
     
         25 . The method of  claim 24 , wherein the C 4-30 -diester of adipic acid is present at 0.05 wt % to 0.5 wt % of the lubricating composition. 
     
     
         26 . The method of  claim 24 , wherein the C 4-30 -diester of adipic acid is present at 0.1 wt % to 0.3 wt % of the lubricating composition. 
     
     
         27 . The method of  claim 24 , wherein the alcohol-derived portion of the diester is C 8-20 . 
     
     
         28 . The method of  claim 24 , wherein the alcohol-derived portion of the diester is C 10-15 . 
     
     
         29 . The method of  claim 24 , wherein the alcohol-derived portion of the diester is C 13 . 
     
     
         30 . The method of  claim 24 , wherein the ester groups of the diester are branched. 
     
     
         31 . The method of  claim 24 , wherein the lubricating composition further comprises a phosphorus containing compound, wherein the phosphorus containing compound is an amine salt of a phosphoric acid ester. 
     
     
         32 . The method of  claim 24 , wherein the lubricating composition comprises (a) an oil of lubricating viscosity, and a friction modifier package consisting of a C 4-30 -diester of adipic acid, and a phosphorus containing compound, wherein the phosphorus containing compound is an amine salt of a phosphoric acid ester. 
     
     
         33 . The method of  claim 31 , wherein the phosphorus compound is present at 0.01 wt % to 5 wt % of the lubricating composition. 
     
     
         34 . The method of  claim 24 , wherein the lubricating composition comprises (a) an oil of lubricating viscosity, and a friction modifier package consisting of a C 4-30 -diester of adipic acid, and 0.05 wt % to 4.5 wt % of a phosphorus containing compound. 
     
     
         35 . The method of  claim 24  further comprising a sulphur-containing compound, wherein the sulphur-containing compound is a dimercaptothiadiazole or derivative, or mixtures thereof. 
     
     
         36 . The method of  claim 31 , wherein the phosphorus containing compound is an amine salt of a phosphoric acid ester, wherein the amine salt of a phosphoric acid ester is an amine salt of (i) a hydroxy-substituted di-ester of phosphoric acid, (ii) a phosphorylated hydroxy-substituted di- or tri-ester of phosphoric acid, or (iii) or mixtures thereof. 
     
     
         37 . The method of  claim 24 , wherein the lubricating composition further comprises a boron-containing compound, wherein the boron-containing compound is a borated dispersant, a borate ester or a borated phospholipid, typically a borated phospholipid. 
     
     
         38 . The method of  claim 24 , wherein the limited slip differential has a plate material of steel on paper.