Lubricant With Enhanced Energy Efficiency

Abstract

Lubricant compositions useful especially for the lubrification of gears, having a boundary loss coefficient X LG of 0.6 to 0.8 measured at temperatures of 40 to 120° C. with a modified method according to DIN 51354, whereby the lubricant composition contains of a base oil a optional additives, whereby the base oil is selected from complex ester, said, said complex ester having a kinematic viscosity at 40° C. of greater than 400 and up to 50 000 mm 2 /s.

1 . A lubricant composition having a boundary loss coefficient X LG  of 0.6 to 0.8 measured at temperatures of 40 to 120° C. with a modified method according to DIN 51354, whereby the lubricant composition comprises a base oil and optional additives, whereby the base oil comprises complex esters, said complex esters 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 
 b) polyols and monoalcohols and dicarboxylic acids, or 
 c) polyols and monoalcohols and monocarboxylic acids and dicarboxylic acids. 
 
     
     
         2 . The lubricant composition according to  claim 1 , wherein the ester is obtained by reaction of a). 
     
     
         3 . The lubricant composition according to  claim 1 , wherein the acid part of the ester comprises a blend of at least two different dibasic acids. 
     
     
         4 . The lubricant composition according to  claim 3 , wherein the dibasic acids independently contain from 8 to 18 C-atoms. 
     
     
         5 . The lubricant composition according  claim 1 , wherein the acid part of the esters is selected from at least one branched dibasic acid. 
     
     
         6 . The lubricant composition according to  claim 1 , wherein the acid part of the esters comprises sebacic acid, adipic acid, succinic acid, glutaric acid, isostearic acid, or mixtures thereof. 
     
     
         7 . The lubricant composition according to  claim 1 , wherein the alcohol part of the ester comprises glycerol, neopentylglycol, an oligo-polyglycerol, a polyglycerol, trimethylolpropane, pentaerythritol, or mixtures thereof. 
     
     
         8 . The lubricant composition according to  claim 7 , wherein the alcohol part of the ester comprises pentaerythritol or trimethylolpropane or mixtures thereof. 
     
     
         9 . The lubricant composition according to  claim 1 , comprising from 0.01 to 5 wt % of additives, based on the total weight of the lubricant composition. 
     
     
         10 . The lubricant composition according to  claim 1 , comprising the complex ester in an amount in the range of 1 to 99.9 wt % based on the total weight of the lubricant. 
     
     
         11 . The lubricant composition according to  claim 1 , further comprising as additional oils in an amount in the range of 1 to 60 wt %, based on the total weight of the lubricant, an oil selected from the group consisting of esters that are not complex, polyalphaolefins, mineral oils, polymers, polyalkylene glycols, and mixtures thereof. 
     
     
         12 . A method of lubricating gears, the method comprising using the lubricant composition according to  claim 1  as an energy efficient lubricant for the lubrication of gears. 
     
     
         13 . The lubricant composition according to  claim 10 , comprising the complex ester in an amount in the range of 10 to 80 wt %, based on the total weight of the lubricant. 
     
     
         14 . The lubricant composition according to  claim 13 , comprising the complex ester in an amount in the range of 50 to 75 wt %, based on the total weight of the lubricant. 
     
     
         15 . The lubricant composition according to  claim 11 , comprising the additional oils in an amount in the range of 5 to 45 wt %, based on the total weight of the lubricant. 
     
     
         16 . The method of  claim 12  wherein the gears are gears of wind turbines.