Lubricant composition

Abstract

The present invention relates to a lubricant composition Lubricant composition comprising at least one oil-soluble organic molybdenum compound, and at least one alkyl- or aryl-substituted ammonium tungstate, wherein the weight ratio of molybdenum to tungsten in the lubricant composition is at least 2.5:1, and the amount of molybdenum in the lubricant composition is at least 350 ppm based on the total weight of the lubricant composition. The compositions provide unexpected and substantially improved friction and abrasion properties over related compositions devoid of the invention. When using these lubricant compositions, for example in internal combustion engines, the engine power can be increased and the fuel consumption can be reduced.

What is claimed is: 
     
         1 . Lubricant composition comprising
 at least one oil-soluble organic molybdenum compound, and   at least one alkyl- or aryl-substituted ammonium tungstate,   wherein the weight ratio of molybdenum to tungsten in the lubricant composition is at least 2.5:1, and the amount of molybdenum in the lubricant composition is at least 350 ppm based on the total weight of the lubricant composition.   
     
     
         2 . Lubricant composition according to  claim 1 , wherein the weight ratio of molybdenum to tungsten in the lubricant is between about 3:1 and about 10:1. 
     
     
         3 . Lubricant composition according to  claim 1 , wherein the weight ratio of molybdenum to tungsten in the lubricant is between about 4:1 and about 8:1. 
     
     
         4 . Lubricant composition according to  claim 1 , wherein the amount of molybdenum in the lubricant is less than 0.1 wt.-% Mo based on the total weight of the lubricant composition. 
     
     
         5 . Lubricant composition according to  claim 1 , wherein the amount of molybdenum in the lubricant is less than or equal to 700 ppm and greater than 350 ppm Mo based on the total weight of the lubricant composition. 
     
     
         6 . Lubricant composition according to  claim 1 , wherein the amount of tungsten in the lubricant is less than or equal to 500 ppm based on the total weight of the lubricant composition. 
     
     
         7 . Lubricant composition according to  claim 1 , wherein the amount of tungsten in the lubricant is less than or equal to 200 ppm based on the total weight of the lubricant composition. 
     
     
         8 . Lubricant composition according to  claim 1 , wherein the weight ratio of molybdenum to tungsten in the lubricant is at least about 5:1. 
     
     
         9 . Lubricant composition according to  claim 1 , wherein the organic molybdenum compound is an organic molybdenum complex, prepared from at least one long chain fatty acid oil, diethanolamine or 2-(2-aminoethyl) amino ethanol, and molybdenum trioxide. 
     
     
         10 . Lubricant composition according to  claim 9 , wherein the long chain fatty acid oil is an oil of a saturated fatty acid having 8 to 18 carbon atoms, in particular selected from the group consisting of caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid and stearic acid, or an unsaturated fatty acid with up to 18 carbon atoms, in particular oleic acid or linoleic acid, or a mixture of two or more fatty acid oils of the aforementioned type. 
     
     
         11 . Lubricant composition according to  claim 1 , wherein the ammonium tungstate is an organo-ammonium metal compound comprising polytungstate ions and dialkyl-ammonium ions of the type R 2 NH 2   + , wherein the radicals —R are long-chain alkyl groups. 
     
     
         12 . Method for preparing a lubricant composition, comprising the step of: adding to a lubricant base composition a first additive comprising at least one oil-soluble organic molybdenum compound and a second additive comprising at least one alkyl- or aryl-substituted ammonium tungstate, wherein the first additive and the second additive are each added to the lubricant composition in such an amount that the weight ratio of molybdenum to tungsten in the lubricant composition is at least 2.5:1, and the amount of molybdenum in the lubricant composition is at least 350 ppm based on the total weight of the lubricant composition. 
     
     
         13 . Method for preparing a lubricant composition according  claim 12 , wherein the first additive and second additive are first combined to form a combination additive, and the combination additive is added to the lubricant composition.