Molybdenum-containing lubricant for improved power or fuel economy

Abstract

Lubricant compositions of (a) an oil of lubricating viscosity; (b) a molybdenum salt; (c) a monoester of (i) a polyol and (ii) an aliphatic carboxylic acid containing about 12 to about 24 carbon atoms; and (d) a borate ester of a vicinal diol containing 12 to 24 carbon atoms provide good fuel economy and power output to internal combustion engines.

1 . A lubricant composition comprising: 
 (a) an oil of lubricating viscosity;    (b) a molybdenum salt;    (c) a monoester of (i) a polyol and (ii) an aliphatic carboxylic acid containing about 12 to about 24 carbon atoms; and    (d) a borated epoxide containing 12 to 24 carbon atoms.    
   
   
       2 . The composition of  claim 1  wherein the oil of lubricating viscosity is a natural or a synthetic oil composition, optionally containing a viscosity index modifier, selected so as to have an SAE multigrade viscosity rating of 0W-10, 0W-20, 0W-30, 5W-20, 5W-30 or an SAE monograde viscosity rating of 20 or 30.  
   
   
       3 . The composition of  claim 2  wherein the oil of lubricating viscosity is an API Grade II, III, IV, or V oil.  
   
   
       4 . The composition of  claim 2  wherein the oil of lubricating viscosity comprises a synthetic oil.  
   
   
       5 . The composition of  claim 4  wherein the synthetic oil is a blend of a polyalphaolefin and a synthetic ester.  
   
   
       6 . The composition of  claim 1  wherein the molybdenum salt is a molybdenum dihydrocarbyldithiocarbamate.  
   
   
       7 . The composition of  claim 1  wherein the molybdenum salt is the product of (a) reacting a carboxylic acid or reactive equivalent thereof having about 8 to about 34 carbon atoms with an alkylene polyamine; and (b) reacting the product of (a) with, in any order, (i) a molybdenum compound and (ii) carbon disulfide, to form a molybdenum dithiocarbamate.  
   
   
       8 . The composition of  claim 1  wherein the amount of the molybdenum salt is an amount suitable to provide about 50 to about 4000 parts per million by weight Mo to the composition.  
   
   
       9 . The composition of  claim 1  wherein the monoester comprises glycerol monooleate.  
   
   
       10 . The composition of  claim 1  wherein the amount of the monoester is about 0.03 to about 2.0 parts by weight per 100 parts of the oil of lubricating viscosity.  
   
   
       11 . The composition of  claim 1  wherein the borated epoxide is a borate ester of a vicinal diol containing 16-18 carbon atoms.  
   
   
       12 . The composition of  claim 1  wherein the borate ester of (d) is present in an amount to provide about 30 to about 2000 parts per million by weight of boron to the composition.  
   
   
       13 . The composition of  claim 1  further comprising at least one dispersant, at least one metal salt of a dialkyldithiophosphate, at least one sulfurized oil, and at least one overbased detergent.  
   
   
       14 . The composition of  claim 1  further comprising an additional boron-containing compound other than that of (d).  
   
   
       15 . A composition prepared by admixing the components of  claim 1 .  
   
   
       16 . A method for lubricating an internal combustion engine, comprising supplying thereto the composition of  claim 1 .  
   
   
       17 . The composition of  claim 1  wherein the borated epoxide component (d) consists essentially of at least one borated epoxide selected from the group consisting of borated C 14-16  epoxides, borated C 14-18  epoxides, borated C 16-18  epoxides, and borated predominantly-C 16  epoxides.  
   
   
       18 . The use of a molybdenum salt in a lubricant composition for lubricating an internal combustion engine, to impart at least one of improved fuel economy and power output to said engine, wherein said lubricant composition further comprises: 
 (a) an oil of lubricating viscosity;    (c) a monoester of (i) a polyol and (ii) an aliphatic carboxylic acid containing 12 to 24 carbon atoms; and    (d) a borated epoxide containing 12 to 24 carbon atoms.