Diester-based engine oil formulations with improved low noack and cold flow properties

Abstract

The present invention is generally directed to diester-based multi-grade engine oil formulations. The diesters employed have a number a performance benefits in lubricant applications—among them: biodegradability, extreme temperature performance, oxidative stability, solubility for additives and deposit and sludge precursors, flash and fire points. However, ester usage in lubricants has been quite limited due to their high cost. We utilize new proprietary diesters, structurally different from traditional diesters, which are made from fatty acids and alpha olefins in simple processing steps, yet feature performance similar to more traditional lubricant esters.

What is claimed is: 
     
         1 . A multi-grade engine oil comprising:
 a) a diester component, comprising a quantity of at least one diester species having the following structure:   
       
         
           
           
               
               
           
         
         
           wherein R 1 , R 2 , R 3  and R 4  are the same or independently selected from C 2  to C 17  hydrocarbon groups; 
         
         b) a second base oil; and 
         c) an additive package, 
         wherein the second base and third base oil are independently selected from the group consisting of Group I base oil, Group II base oil or Group III base oil. 
       
     
     
         2 . The multi-grade engine oil of  claim 1 , wherein a quantity of at least one diester species comprises a mixture of isomers where R 1  and R 2  are different for each isomer. 
     
     
         3 . The multi-grade engine oil of  claim 1 , further comprising, a third base oil. 
     
     
         4 . The multi-grade engine oil of  claim 1 , wherein the diester has a Noack Volatility between about 6 and 10 wt %, a CCS Viscosity at −30° C. between about 700 and 2000 cP, a pour point less than about −10° C., a cloud point less than about −10° C., a kinematic viscosity at 100° C. between about 2.5 to 6.5 centistokes, a VI greater than about 110 and a BN Oxidator greater than about 20 hours. 
     
     
         5 . The multi-grade engine oil according to  claim 1  or  3 , wherein the second base and third base oil are independently selected from the group consisting of light neutral base oil, medium neutral base oil, Yubase 4, Yubase 6, 150R, 600R, 110RLV, 220R and 100R. 
     
     
         6 . The multi-grade engine oil of  claim 1 , meeting the specifications for SAE viscosity grade 0W-XX or 5W-XX, wherein XX represents the integer 16, 20, 30, or 40. 
     
     
         7 . The multi-grade engine oil of  claim 1 , wherein the multi-grade engine oil meets the SAE J300 standards as revised in January 2009. 
     
     
         8 . The multi-grade engine oil of  claim 1 , having:
 a) a viscosity index between about 140-200;   b) a kinematic viscosity at 100° C. between about 6-10 cSt;   c) a Pour Point less than about −30° C.; and   d) a Noack volatility of less than about 15 wt %,   wherein the multi-grade engine oil is a 0W-SAE grade with a CCS Viscosity at −35° C. less than about 6200 cP or the multi-grade engine oil is a 5W-SAE grade with a CCS Viscosity at −30° C. less than about 6600 cP.   
     
     
         9 . The multi-grade engine oil of  claim 1 , wherein the kinematic viscosity of the multi-grade engine oil at a temperature of 100° C. is between about 3 to 10 centistokes. 
     
     
         10 . The multi-grade engine oil of  claim 1 , wherein the CCS Viscosity at −30° C. less than about 6,600 cP. 
     
     
         11 . The multi-grade engine oil of  claim 1 , wherein the CCS Viscosity at −35° C. less than about 6,200 cP. 
     
     
         12 . The multi-grade engine oil of  claim 1 , wherein the Noack Volatility less than about 15 wt %. 
     
     
         13 . The multi-grade engine oil of  claim 1 , wherein R 1  and R 2  are selected to have a combined carbon number of from 6 to 16 and R 3  and R 4  are selected to have a combined carbon number of from 10 to 34. 
     
     
         14 . The multi-grade engine oil of  claim 1 , wherein R 1  and R 2  of Formula I are selected to have a combined carbon number of C 16 , C 14  or C 12  and R 3  and R 4  are independently selected from the group consisting of C 12  and a mixture of C 6 -C 10 . 
     
     
         15 . The multi-grade engine oil of  claim 1 , wherein the at least one diester species is derived from a C 8  to C 18  olefin and a C 6  to C 14  carboxylic acid. 
     
     
         16 . The multi-grade engine oil of  claim 2 , wherein said composition comprises quantities of at least two different diester isomers. 
     
     
         17 . The multi-grade engine oil of  claim 1 , wherein the at least one diester species has a molecular mass that is from at least about 340 a.m.u. to at most about 780 a.m.u. 
     
     
         18 . The multi-grade engine oil of  claim 1 , wherein the at least one diester species is selected from the group consisting of decanoic acid 2-decanoyloxy-1-hexyl-octyl ester and its isomers, tetradecanoic acid-1-hexyl-2-tetradecanoyloxy-octyl esters and its isomers, dodecanoic acid 2-dodecanoyloxy-1-hexyl-octyl ester and its isomers, hexanoic acid 2-hexanoyloxy-1-hexy-octyl ester and its isomers, octanoic acid 2-octanoyloxy-1-hexyl-octyl ester and its isomers, hexanoic acid 2-hexanoyloxy-1-pentyl-heptyl ester and isomers, octanoic acid 2-octanoyloxy-1-pentyl-heptyl ester and isomers, decanoic acid 2-decanoyloxy-1-pentyl-heptyl ester and isomers, decanoic acid-2-cecanoyloxy-1-pentyl-heptyl ester and its isomers, dodecanoic acid-2-dodecanoyloxy-1-pentyl-heptyl ester and isomers, tetradecanoic acid 1-penty-2-tetradecanoyloxy-heptyl ester and isomers, tetradecanoic acid 1-butyl-2-tetradecanoyloxy-hexy ester and isomers, dodecanoic acid-1-butyl-2-dodecanoyloxy-hexyl ester and isomers, decanoic acid 1-butyl-2-decanoyloxy-hexyl ester and isomers, octanoic acid 1-butyl-2-octanoyloxy-hexyl ester and isomers, hexanoic acid 1-butyl-2-hexanoyloxy-hexyl ester and isomers, tetradecanoic acid 1-propyl-2-tetradecanoyloxy-pentyl ester and isomers, dodecanoic acid 2-dodecanoyloxy-1-propyl-pentyl ester and isomers, decanoic acid 2-decanoyloxy-1-propyl-pentyl ester and isomers, octanoic acid 1-2-octanoyloxy-1-propyl-pentyl ester and isomers, hexanoic acid 2-hexanoyloxy-1-propyl-pentyl ester and isomers, and mixtures thereof. 
     
     
         19 . The multi-grade engine oil of  claim 1 , wherein the multi-grade engine oil is formulated as a 0W-20 SAE 0W-16 or 5W-20 SAE engine oil.