Lubricating grease composition

Abstract

A lubricating grease composition contains a major amount of lubricating base oil, at least one thickener and at least one agent for reducing the coefficient of friction. The agent for reducing the coefficient of friction comprises a metal oxide that has a specific surface area of at least 100 m 2 /g and that is selected from the group consisting of titanium oxide, silicon dioxide, aluminum oxide and tin dioxide.

1 . A lubricating grease composition containing a major amount of lubricating base oil, at least one thickener and at least one agent for reducing the coefficient of friction, said agent for reducing said coefficient of friction comprising a metal oxide that has a specific surface area of at least 100 m 2 /g and that is selected from the group consisting of titanium oxide, silicon dioxide, aluminum oxide and tin dioxide.  
     
     
         2 . The composition according to  claim 1 , wherein said metal oxide is present in an amount of 0.1% to 5% by weight.  
     
     
         3 . The composition according to  claim 1 , wherein said metal oxide is present in an amount of 0.5% to 2.5% by weight.  
     
     
         4 . The composition according to  claim 1 , wherein said specific surface area is at least 150 m 2 /g.  
     
     
         5 . The composition according to  claim 4 , wherein said specific surface area is at least 200 m 2 /g  
     
     
         6 . The composition according to  claim 1 , wherein said metal oxide is a highly dispersed silica.  
     
     
         7 . The composition according to  claim 6 , wherein said highly dispersed silica is hydrophobized.  
     
     
         8 . The composition according to  claim 6 , wherein said highly dispersed silica has a specific surface area of between 200 m 2 /g and 300 m 2 /g.  
     
     
         9 . The composition according to  claim 1 , wherein said base oil is selected from the group consisting of mineral oil, synthetic oils and mixtures thereof.  
     
     
         10 . The composition according to  claim 9 , wherein said base oil is a synthetic oil on the basis of a polyalkylene glycol.  
     
     
         11 . The composition according to  claim 10 , wherein said base oil comprises polypropylene glycol, trimethylol propane ester and alkyl benzene.  
     
     
         12 . The composition according to  claim 1 , wherein said thickener is a lithium soap in an amount of 2% to 30% by weight.  
     
     
         13 . The composition according to  claim 12 , wherein said thickener comprises said lithium soap of 12-hydroxy stearic acid and azelaic acid.  
     
     
         14 . The composition according to  claim 1 , comprising additional additives from the group of plasticizers, modifiers of the coefficient of friction, anticorrosion agents and antioxidants.  
     
     
         15 . A method of reducing and stabilizing the coefficient of friction of lubricating grease wherein the lubricating grease is provided with a metal oxide selected from the group consisting of silicon dioxide, titanium oxide, tin dioxide and aluminum oxide having a specific surface area of at least 100 m 2 /g.