Use of ester base stocks to improve viscosity index and efficiency in driveline and industrial gear lubricating fluids

Abstract

The disclosed technology relates to lubricants for driveline and industrial gears containing a mono-ester or a mixture of mono- and di-esters, as well as a method of lubricating driveline and industrial gears with such a lubricant.

1 ) A lubricant composition comprising:
 a) a hydrocarbon lubricating base stock,   b) from about 1 to about 15 wt. % of a carboxylic acid mono-ester.   
     
     
         2 ) The lubricant composition of  claim 1 , wherein the carboxylic acid mono-ester comprises a C 8  to C 18  linear or branched carboxylic acid. 
     
     
         3 ) The lubricant composition of  claim 1 , wherein the carboxylic acid mono-ester comprises a C 6  to C 12  linear or branched alkoxy group. 
     
     
         4 ) The lubricant composition of  claim 1 , wherein the carboxylic acid mono-ester comprises a lauric acid mono-ester, tallow acid mono-ester, oleic acid mono-ester, palmitic acid mono ester, and combinations thereof. 
     
     
         5 ) The lubricant composition of  claim 1 , wherein the carboxylic acid mono-ester comprises a 2-ethylhexyl alkoxy group. 
     
     
         6 ) The lubricant composition of  claim 1 , wherein the carboxylic acid mono-ester comprises at least one of 2-ethylhexyl tallate, 2-ethylhexyl oleate, 2-ethylhexyl laurate, 2-ethylhexyl palmitate, and combinations thereof. 
     
     
         7 ) The lubricant composition of  claim 1 , further comprising from about 1 to about 15 wt. % of a dicarboxylic acid di-ester. 
     
     
         8 ) The lubricant composition of  claim 1 , wherein the dicarboxylic acid di-ester comprises a C 3  to C 12  linear or branched di carboxylic acid. 
     
     
         9 ) The lubricant of  claim 1 , where the dicarboxylic acid di-ester comprises adipic acid diester, azelaic acid diester, and combinations thereof. 
     
     
         10 ) The lubricant composition of  claim 1 , wherein the dicarboxylic acid di-ester comprises at least one of di-2-ethylhexyl azelate, diisotridecyl adipate, diisooctyl adipate, and combinations thereof. 
     
     
         11 ) The lubricant composition of  claim 1  wherein the hydrocarbon lubricating base stock comprises an American Petroleum Institute (“API”) Group IV polyalphaolefin. 
     
     
         12 ) The lubricant composition of  claim 1  wherein the hydrocarbon lubricating base stock comprises an American Petroleum Institute (“API”) Group III oil mineral oil. 
     
     
         13 ) The lubricant composition of  claim 1  wherein the hydrocarbon lubricating base stock comprises an American Petroleum Institute (“API”) Group II oil mineral oil.