Ether-Based Lubricant Compositions, Methods and Uses

Abstract

The present invention provides a lubricant composition for an internal combustion engine comprising a base oil of lubricating viscosity, wherein the base oil comprises an ether base stock of formula (A): where: R a and R b are aliphatic hydrocarbyl groups and may be the same or different; wherein at least one of R a and R b is branched-chain alkyl, alkoxy-substituted-alkyl or cycloalkyl-substituted-alkyl; the lubricant composition further comprising at least one aminic anti-oxidant and/or at least one phenolic anti-oxidant; and wherein the total combined amount of aminic and phenolic anti-oxidant in the lubricant composition is not more than 4.0% by weight of the lubricant composition. In some embodiments, the ether base stock has the formula (1): where: R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are as defined herein. The lubricant composition may be used for lubricating a surface in an internal combustion engine as well as for improving the fuel economy performance and/or piston cleanliness performance of an engine and/or a vehicle, such as an automotive vehicle associated with an internal combustion engine.

1 . A lubricant composition for an internal combustion engine comprising a base oil of lubricating viscosity, wherein the base oil comprises an ether base stock of formula (A): 
       
         
           
           
               
               
           
         
         where: R a  and R b  are aliphatic hydrocarbyl groups and may be the same or different; wherein at least one of R a  and R b  is branched-chain alkyl, alkoxy-substituted-alkyl or cycloalkyl-substituted-alkyl;
 the lubricant composition further comprising at least one aminic anti-oxidant and/or at least one phenolic anti-oxidant; and 
 wherein the total combined amount of aminic and phenolic anti-oxidant in the lubricant composition is not more than 4.0% by weight of the lubricant composition. 
 
       
     
     
         2 . The lubricant composition of  claim 1 , wherein R a  and R b  are independently selected from alkyl, alkoxy-substituted-alkyl or cycloalkyl-substituted-alkyl, provided that when R a  and R b  are both alkyl, at least one of R a  and R b  is/are branched-chain alkyl. 
     
     
         3 . The lubricant composition of  claim 1 , wherein R a  contains more carbon atoms than R b . 
     
     
         4 . The lubricant composition of  claim 1 , wherein R a  contains from 12 to 30 carbon atoms, and/or R b  contains from 2 to 20 carbon atoms. 
     
     
         5 . The lubricant composition of  claim 1 , wherein the ether base stock is of formula (1): 
       
         
           
           
               
               
           
         
         where: R 1  and R 2  are alkyl or, together with the carbon atom to which they are attached, cycloalkyl;
 R 3 , R 4  and R 5  are H or alkyl; 
 R 6  is alkyl or 
 
       
       
         
           
           
               
               
           
         
         where: R 7  and R 8  are H, alkyl or, together with the carbon atom to which they are attached, cycloalkyl;
 R 9  is H or alkyl; 
 X is alkylene or is absent; and 
 p is 0, 1, 2 or 3; and 
 m and n are 0, 1, 2 or 3, wherein m is 0 when R 4  and R 5  are H. 
 
       
     
     
         6 . The lubricant composition of  claim 5 , wherein R 1  and R 2  are C 1-15  alkyl or, together with the carbon atom to which they are attached, C 5-30  cycloalkyl; and/or wherein R 3 , R 4  and R 5  are H or C 1-15  alkyl. 
     
     
         7 . The lubricant composition of  claim 5 , wherein m and n are 0, 1 or 2. 
     
     
         8 . The lubricant composition of  claim 5 , wherein the ether base stock has the formula (4): 
       
         
           
           
               
               
           
         
         where: R 1  and R 4  are alkyl;
 R 3  and R 5  are H or alkyl. 
 
       
     
     
         9 . The lubricant composition of  claim 5 , wherein the ether base stock has the formula (7): 
       
         
           
           
               
               
           
         
         where: R 1  and R 2  are alkyl or, together with the carbon to which they are attached, cycloalkyl;
 R 3 , R 4  and R 5  are H or alkyl; and 
 R 6  is alkyl. 
 
       
     
     
         10 . The lubricant composition of  claim 1 , wherein the ether base stock contains a total number of carbons atoms of from 20 to 50. 
     
     
         11 . The lubricant composition of  claim 1 , wherein the ether base stock is prepared from bio-derived feedstock containing greater than 50% by weight of biobased carbon. 
     
     
         12 . The lubricant composition of  claim 1 , wherein the base oil of the lubricant composition comprises greater than 10% by weight of the ether base stock and/or wherein the lubricant composition comprises greater than 50% by weight of the base oil. 
     
     
         13 . The lubricant composition of  claim 12 , wherein the base oil of the lubricant composition further comprises a base stock selected from Group I, Group II, Group III, Group IV and Group V base stocks and mixtures thereof. 
     
     
         14 . The lubricant composition of  claim 1 , wherein the lubricant composition has at least one of:
 a kinematic viscosity at 40° C. of less than 60 cSt;   a kinematic viscosity at 100° C. of less than 12 cSt;   a viscosity index of greater than 100;   a viscosity at 150° C. and a shear rate of 10 6  s −1  of no greater than 3 cP; and   a Noack volatility of less than 25% by weight.   
     
     
         15 . The lubricant composition of  claim 1 , wherein the lubricant composition has at least one of:
 an oxidative stability performance on a CEC-L-088-02 test indicated by an absolute viscosity increase at 40° C. of no more than 45 cSt;   an oxidative stability performance on a CEC-L-109-14 test indicated by an increase in kinematic viscosity at 100° C. of less than 200% at 216 hours and/or less than 200% at 168 hours;   a fuel economy performance on a CEC-L-054-96 test of at least 2.5%; and   a piston cleanliness performance on a CEC-L-088-02 test indicated by an overall piston merit of at least 8.5.   
     
     
         16 . The lubricant composition of  claim 1 , wherein the total combined amount of aminic and phenolic anti-oxidant in the lubricant composition is not more than 3.0% by weight of the lubricant composition. 
     
     
         17 . The lubricant composition of  claim 1 , wherein the total combined amount of aminic and phenolic anti-oxidant in the lubricant composition is at least 0.25% by weight of the lubricant composition. 
     
     
         18 . The lubricant composition of  claim 1 , wherein the total amount of non-aminic and non-phenolic antioxidant in the lubricant composition is not more than 1.0% by weight of the lubricant composition. 
     
     
         19 . The lubricant composition of  claim 1 , wherein the lubricant composition comprises aminic anti-oxidant or phenolic anti-oxidant but not both aminic anti-oxidant and phenolic anti-oxidant. 
     
     
         20 . The lubricant composition of  claim 1 , wherein the at least one phenolic anti-oxidant is selected from alkylated mono-phenols, alkylated hydroquinones, hydroxylated thiodiphenyl ethers, alkylidenebisphenols, acylaminophenols, and sulphurised alkyl phenols and alkali and alkaline earth metal salts thereof. 
     
     
         21 . The lubricant composition of  claim 1 , wherein the at least one phenolic anti-oxidant is selected from 2-t-butyl-4-heptyl phenol, 2-t-butyl-4-octyl phenol, 2-t-butyl-4-dodecyl phenol, 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-heptylphenol, 2,6-di-t-butyl-4-dodecylphenol, 2-methyl-6-t-butyl-4-heptylphenol, 2-methyl-6-t-butyl-4-dodecylphenol, 4,4′-methylenebis(2,6-di-t-butylphenol), 2′-bis(4-heptyl-6-t-butylphenol), 2,2′-bis(4-octyl-6-t-butylphenol), 2,2′-bis(4-dodecyl-6-t-butylphenol), 4, 4′-bis(2,6-di-t-butylphenol), 4,4′-methylene-bis(2,6-di-t-butylphenol) and derivatives thereof. 
     
     
         22 . The lubricant composition of  claim 1 , wherein the at least one aminic anti-oxidant is selected from alkylated and non-alkylated aromatic amines, alkylated diphenylamines, N-alkylated phenylenediamines, phenyl-α-naphthylamine, and alkylated phenyl-α-naphthylamines. 
     
     
         23 . The lubricant composition of any  claim 1 , wherein the at least one aminic anti-oxidant is selected from p,p-dioctylphenylamine, t-octylphenyl-α-naphthylamine, p-octylphenyl-α-naphthylamine, monooctyldiphenylamine, N,N-di(2-naphthyl)-p-phenylenediamine, phenyl-1-naphthylamine, phenyl-2-naphthylamine, an alkylphenyl-1-naphthylamine, an alkylphenyl-2-naphthylamine and derivatives thereof. 
     
     
         24 . The lubricant composition of  claim 1 , wherein the amount of phosphorus contained in the lubricant composition is less than 0.5 wt. % based on the total weight of the lubricant composition. 
     
     
         25 . The lubricant composition of  claim 1 , wherein the amount of boron contained in the lubricant composition is from 0.005 wt. % to 0.05 wt. %. 
     
     
         26 . The lubricant composition of  claim 1 , wherein the amount of magnesium contained in the lubricant composition is from 0.025 wt. % to 0.5 wt. %. 
     
     
         27 . The lubricant composition of  claim 1 , wherein the lubricant composition comprises one or more dihydrocarbyl dithiophosphate metal salts in an amount of from 0.01 wt. % to 10.0 wt. %. 
     
     
         28 . A method of preparing a lubricant composition, said method comprising providing a base oil as defined in  claim 1  and blending the base oil with at least one aminic anti-oxidant and/or at least one phenolic anti-oxidant such that the total combined amount of aminic and phenolic anti-oxidant in the lubricant composition is not more than 4.0% by weight of the lubricant composition, and optionally also blending one or more additional lubricant additives, in order to prepare the lubricant composition. 
     
     
         29 . A method of lubricating a surface, said method comprising supplying a lubricant composition as defined in  claim 1  to said surface, such as wherein the lubricant composition is supplied to a surface in an internal combustion engine. 
     
     
         30 . (canceled) 
     
     
         31 . (canceled) 
     
     
         32 . A method of improving the fuel economy performance and/or piston cleanliness performance of an engine and/or a vehicle, comprising the step of providing the engine and/or the vehicle with a lubricant composition according to  claim 1 . 
     
     
         33 . (canceled)