Lubricant Compounds Containing Complex Esters

Abstract

Disclosed are lubricant compounds with a good shear stability defined by the loss of the kinematic viscosity at 100° C., containing base oil and a synthetic complex ester, the complex ester having a kinematic viscosity at 40° C. of greater than 400 and up to 50,000 mm 2 /s and being obtained by reaction of a) polyols and monocarboxylic acids and dicarboxylic acids, or of b) polyols and mono-alcohols and dicarboxylic acids, or of c) polyols and mono-alcohols and monocarboxylic acids and dicarboxylic acids. In addition the use of said lubricant compounds containing the complex esters as oils for vehicle transmission, axle, industrial drives, compressors, turbines or engines is described.

1 . A lubricant composition having a good shear stability determined by the loss of kinematic viscosity at 100° C., comprising base oil and a synthetic complex ester, said complex ester having a kinematic viscosity at 40° C. of greater than 400 and up to 50000 mm 2 /s and being obtained by reaction of:
 a) polyols and monocarboxylic acids and dicarboxylic acids, or   b) polyols and monoalcohols and dicarboxylic acids, or   c) polyols and monoalcohols and monocarboxylic acids and dicarboxylic acids.   
     
     
         2 . The lubricant composition of  claim 1 , wherein the loss of kinematic viscosity at 100° C.
 i) for transmission oils, axle oils and clutch oils for automatic and manual transmission, determined to CEC L-45-T-93 (20 hours), is less than 8%,   ii) for hydraulic fluids, for industrial transmission oils with stationary uses, for oils for lubricating wind turbines, for gas turbine oils, for compressor oils and shock absorber fluids, determined to CEC L-45-T-93 (20 hours), is less than 15%,   iii) for two-stroke and four-stroke engine oils and for diesel and gasoline motor oils, determined to ASTM D 3945 (30 cycles), is less than 15%.   
     
     
         3 . The lubricant composition of  claim 1 , wherein said complex ester is present in a concentration of from about 3 to about 90% by weight based on the total amount of lubricant composition. 
     
     
         4 . The lubricant composition of  claim 1 , wherein said monocarboxylic acids used in the reaction according to a) are branched monocarboxylic acids or mixtures of linear and branched monocarboxylic acids, each of which has a carbon number of from about 5 to about 40 carbon atoms. 
     
     
         5 . The lubricant composition of  claim 1 , wherein said polyols are branched or linear alcohols of the general formula (I) R 1 (OH) n  in which R 1  is an aliphatic or cycloaliphatic group having from about 2 to about 20 carbon atoms and n is at least 2. 
     
     
         6 . The lubricant composition of  claim 1 , wherein said monoalcohols are branched or linear alcohols of the general formula (II) (R 2 OH) in which R 2  is an aliphatic or cycloaliphatic group having from about 2 to about 20 carbon atoms. 
     
     
         7 . The lubricant composition of  claim 1 , wherein said dicarboxylic acids are selected from the group consisting of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, brassylic acid, thapsic acid and phellogenic acid. 
     
     
         8 . The lubricant composition of  claim 1 , further comprising a polar polymer in a concentration of from about 0.5 to about 30% by weight based on the total amount of lubricant composition. 
     
     
         9 . The lubricant composition of  claim 1 , wherein said polar polymer is selected from the group consisting of polyalkyl methacrylate, alkyl fumarate-alpha-olefin copolymer, alkyl maleate-alpha-olefin copolymer, propylene oxide polymer, ethylene oxide-propylene oxide copolymer and alkyl methacrylate-alpha-olefin copolymer. 
     
     
         10 . The lubricant composition of  claim 1 , further comprising additives selected from the group consisting of polymer thickeners, viscosity index improvers, antioxidants, corrosion inhibitors, detergents, dispersants, demulsifiers, defoamers, dyes, wear protection additives, EP (extreme pressure) additives, AW (antiwear) additives and friction modifiers. 
     
     
         11 . A method of lubricating engines, comprising using the lubricant compositions of  claim 1  as vehicle transmission oil, axle oil, industrial transmission oil, compressor oil, turbine oil or motor oil. 
     
     
         12 . The lubricant composition of  claim 1  further comprising a polar polymer in a concentration of from about 1 to about 18% by weight based on the total amount of lubricant composition. 
     
     
         13 . The lubricant composition of  claim 1  further comprising a polar polymer in a concentration of from about 2 to about 12% by weight based on the total amount of lubricant composition.