Additive For Lubricant

Abstract

An additive for lubricants exhibiting high oxidation stability, high thermal stability, and high No x resistance, and having excellent functions as an extreme-pressure additive or wear-resistant agent and a lubricant composition containing the additive are provided The present invention provides an additive for lubricants comprising a phosphate ester derivative represented by the general formula [I]: wherein Y represents sulfur (S) or oxygen (O); R 1 represents a monovalent organic group having 4 to 24 carbon atoms; R 2 represents a divalent organic group having 1 to 6 carbon atoms; and n represents an integer of 1 to 3. The present invention also provides a lubricant composition containing the derivative.

1 . An additive for lubricants comprising a phosphate ester derivative (A) represented by the general formula [I]: 
       
         
           
           
               
               
           
         
       
       wherein Y represents sulfur (S) or oxygen (O); R 1  represents a monovalent organic group having 4 to 24 carbon atoms; R 2  represents a divalent organic group having 1 to 6 carbon atoms; and n represents an integer of 1 to 3. 
     
     
         2 . An additive for lubricants comprising a reaction product of a zinc compound (B) with a phosphate ester derivative (A) represented by the general formula [I]: 
       
         
           
           
               
               
           
         
       
       wherein Y represents sulfur (S) or oxygen (O); R 1  represents a monovalent organic group having 4 to 24 carbon atoms; R 2  represents a divalent organic group having 1 to 6 carbon atoms; and n represents an integer of 1 to 3. 
     
     
         3 . An additive for lubricants comprising a mixture of an organic zinc compound (C) and a phosphate ester derivative (A) represented by the general formula [I]: 
       
         
           
           
               
               
           
         
       
       wherein Y represents sulfur (S) or oxygen (O); R 1  represents a monovalent organic group having 4 to 24 carbon atoms; R 2  represents a divalent organic group having 1 to 6 carbon atoms; and n represents an integer of 1 to 3. 
     
     
         4 . The additive for lubricants in accordance with any one of  claims 1  to  3 , wherein Y in the general formula (I) is oxygen (O). 
     
     
         5 . The additive for lubricants in accordance with  claim 2 , wherein the zinc compound (B) is at least one compound selected from the group consisting of zinc metal, zinc oxide, organic zinc compounds, zinc salts of oxyacids, zinc halides, and zinc complexes. 
     
     
         6 . The additive for lubricants in accordance with  claim 5 , wherein the zinc compound (B) is at least one compound selected from the group consisting of zinc, zinc oxide, zinc hydroxide, zinc carbonate, dimethylzinc, diphenylzinc, and zinc complexes. 
     
     
         7 . The additive for lubricants in accordance with  claim 3 , wherein the organic zinc compound (C) is at least one compound selected from the group consisting of zinc alkylcarboxylates, zinc alkenylcarboxylates, zinc alkylphenylcarboxylates, and zinc alkenylphenylcarboxylates. 
     
     
         8 . The additive for lubricants in accordance with  claim 7 , wherein the organic zinc compound (C) is at least one compound selected from the group consisting of zinc oleate, zinc isostearate, zinc stearate, zinc alkylphenylcarboxylates, and zinc alkylsalicylates. 
     
     
         9 . An additive composition for lubricants comprising the additive for lubricants in accordance with any one of  claims 1  to  8 . 
     
     
         10 . A lubricant composition comprising a lubricant base oil and the additive for lubricants in accordance with any one of  claims 1  to  8  in an amount of 0.001 to 0.5% by mass in terms of elemental phosphorus. 
     
     
         11 . A lubricant composition for internal-combustion engines comprising a lubricant base oil and the additive for lubricants in accordance with any one of  claims 1  to  8  in an amount of 0.001 to 0.5% by mass in terms of elemental phosphorus. 
     
     
         12 . A method of producing an additive for lubricants, comprising reacting the phosphate ester derivative (A) with the zinc compound (B) in accordance with  claim 2  or  4 .