Silicone grease composition

Abstract

The invention provides a silicone grease composition where the high friction properties are improved, with no decrease of the wear preventive characteristics. The silicone grease composition contains a thickener, a base oil containing a silicone oil in an amount of 50 mass % or more of the total mass of the base oil, and a metallic oxide with a Mohs hardness of 6 or less as a friction modifier.

1 . A silicone grease composition comprising a thickener; a base oil comprising a silicone oil in an amount of 50 mass % or more of the total mass of the base oil; and a friction modifier comprising a metallic oxide with a Mohs hardness of 6 or less. 
     
     
         2 . The silicone grease composition of  claim 1 , wherein the metallic oxide has a Mohs hardness of 2 to 6. 
     
     
         3 . The silicone grease composition of  claim 1 , wherein the metallic oxide is magnesium oxide, zinc oxide or molybdenum oxide. 
     
     
         4 . The silicone grease composition of  claim 1 , wherein the metallic oxide is contained in an amount of 0.1 to 10 mass % based on the total mass of the composition. 
     
     
         5 . The silicone grease composition of  claim 1 , wherein the silicone oil is represented by the following formula (1):
   (CH 3 ) 3 SiO-[-Si(R1)(R2)-O-]n-Si(CH 3 ) 3    (1)
   
       wherein R1 and R2 are each independently methyl group or phenyl group, the ratio of group to the whole organic groups being 50 to 100 mol. %. 
     
     
         6 . The silicone grease composition of  claim 1 , wherein the thickener is a diurea compound represented by the following formula (2):
   R3-NHCONH-R4-NHCONH-R5   (2)
   
       wherein R3 and R5, which may be the same or different, each represent a monovalent hydrocarbon group having 4 to 20 carbon atoms and R4 is a bivalent aromatic hydrocarbon group having 6 to 15 carbon atoms. 
     
     
         7 . The silicone grease composition of  claim 1 , wherein the thickener is a mixture of the following three kinds of diurea compounds represented by formula (2-1), (2-2) and (2-3): 
       
         
           
           
               
               
           
         
         wherein R is octadecyl group. 
       
     
     
         8 . The silicone grease composition of  claim 1 , wherein the metallic oxide has an average particle diameter of 2 μm or less.