Lubricating oil compositions comprising a molybdenum compound and a zinc dialkyldithiophosphate

Abstract

Provided herein are lubricating oil compositions comprising a major amount of a base oil, at least one oil-soluble molybdenum compound and a zinc dialkyldithiophosphate compound, wherein the molybdenum content derived from the molybdenum compound is at least 10 ppm based on the total weight of the lubricating oil composition and the phosphorus content derived from the zinc dialkyldithiophosphate compound is about 200 to 500 ppm based on the total weight of the lubricating oil composition. The lubricating oil composition can further comprise at least one additive. Methods of making and using the lubricating oil compositions are also described.

1 . A lubricating oil composition comprising:
 i) a major amount of a base oil,   ii) at least one oil-soluble molybdenum compound and   iii) a zinc dialkyldithiophosphate compound,   
       wherein the molybdenum content derived from the molybdenum compound is at least 10 ppm Molybdenum based on the total weight of the lubricating oil composition and the phosphorus content derived from the zinc dialkyldithiophosphate compound is about 200 ppm to 500 ppm based on the total weight of the lubricating oil composition. 
     
     
         2 . The lubricating oil composition of  claim 1 , wherein the oil-soluble molybdenum compound is selected from molybdenum dithiocarbamate, molybdenum dithiophosphate, molybdenum dithiophosphinate, molybdenum xanthate, molybdenum thioxanthate, molybdenum sulfide and a mixture thereof. 
     
     
         3 . The lubricating oil composition of  claim 1 , wherein the oil-soluble molybdenum compound is selected from molybdenum dithiocarbamate, molybdenum-succinimide complex and a mixture thereof. 
     
     
         4 . The lubricating oil composition of  claim 1 , wherein the molybdenum content derived from the molybdenum compound is from about 10 to 10,000 ppm molybdenum based on the total weight of the lubricating oil composition. 
     
     
         5 . The lubricating oil composition of  claim 1 , wherein the molybdenum content derived from the molybdenum compound is from about 50 to 1500 ppm molybdenum based on the total weight of the lubricating oil composition. 
     
     
         6 . The lubricating oil composition of  claim 1 , wherein the molybdenum content derived from the molybdenum compound is from about 250 to 1200 ppm molybdenum based on the total weight of the lubricating oil composition 
     
     
         7 . The lubricating oil composition of  claim 1 , wherein the zinc dialkyldithiophosphate comprises a straight or branched alkyl group having 3 to 30 carbon atoms. 
     
     
         8 . The lubricating oil composition of  claim 1 , wherein the zinc dialkyldithiophosphate comprises an alkyl selected from ethyl, propyl, butyl, pentyl, methylpentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl. 
     
     
         9 . The lubricating oil composition of  claim 1 , wherein the phosphorus content derived from the zinc dialkyldithiophosphate compound is about 200, 250, 300, 350, 400, 450 or 500 ppm based on the total weight of the lubricating oil composition. 
     
     
         10 . The lubricating oil composition of  claim 1 , wherein the phosphorus content derived from the zinc dialkyldithiophosphate compound is about 250 ppm based on the total weight of the lubricating oil composition. 
     
     
         11 . The lubricating oil composition of  claim 1  further comprising at least one additive selected from the group consisting of antioxidants, antiwear agents, detergents, rust inhibitors, demulsifiers, friction modifiers, multi-functional additives, viscosity index improvers, pour point depressants, foam inhibitors, metal deactivators, dispersants, corrosion inhibitors, lubricity improvers and combinations thereof. 
     
     
         12 . A method of making a lubricating oil composition comprising the step of mixing:
 i) a major amount of a base oil,   ii) at least one oil-soluble molybdenum compound and   iii) a zinc dialkyldithiophosphate compound,   
       wherein the molybdenum content derived from the molybdenum compound is at least 10 ppm based on the total weight of the lubricating oil composition and the phosphorus content derived from the zinc dialkyldithiophosphate compound is about 200 to 500 ppm based on the total weight of the lubricating oil composition. 
     
     
         13 . A method of lubricating a motor engine comprising the step of operating the engine with the lubricating oil composition of  claim 1 . 
     
     
         14 . The method of  claim 15 , wherein the molybdenum content derived from the molybdenum compound is from 10 to 10,000 ppm based on the total weight of the lubricating oil composition. 
     
     
         15 . The method of  claim 15 , wherein the phosphorus content derived from the zinc dialkyldithiophosphate compound is about 200, 250, 300, 350, 400, 450 or 500 ppm based on the total weight of the lubricating oil composition. 
     
     
         16 . The method of  claim 15 , wherein the phosphorus content derived from the zinc dialkyldithiophosphate compound is about 250 ppm based on the total weight of the lubricating oil composition.