Lubricant composition for steel filament and rubber-steel filament composite body

Abstract

A lubricant composition for a surface treatment of a steel filament comprises at least one specified compound as a lubricant component and a rubber-steel filament composite body is prepared by using a steel filament treated with the lubricant composition.

What is claimed is:  
     
         1 . A lubricant composition for steel filament comprising at least one compound selected from the group consisting of sodium 1,6-hexamethylenediamine-dithiosulfate dihydrate, a compound represented by the following formula (1): 
       R 1 —S—S—A—S—S—R 2   (1) 
       (wherein a is an alkylene group having a carbon number of 2-10, and each of R 1  and R 2  is a monovalent organic group containing at least one nitrogen atom), a monoalkali metal salt of triazine thiol, a thiadiazole compound, bivalent or trivalent cobalt salt of an inorganic acid, a schiff base complex represented by the following formula (2) or (3):  
       
         
           
           
               
               
           
         
       
       (wherein R 3  is an alkyl group having a carbon number of 1-10 and X is —R 4 — or —R 4 —NH—R 4 — in which R 4  is an alkylene group having a carbon number of 1 to 10), a cobalt alcholate represented by the following formula (4): 
       (R 5 —O—) 2 —Co  (4) 
       (wherein R 5  is an alkyl group having a carbon number of 1-20, a phenyl alkyl group or an alkyl phenyl group provided that a carbon number of the alkyl group is 1-10), a cobalt complex represented by the following formula (5):  
       
         
           
           
               
               
           
         
       
       (wherein R 6  is an alkyl group having a carbon number of 1-20 or a —NHR 7  group or a —OR 7  group in which R 7  is an alkyl group having a carbon number of 1-20), a metal borate derivative represented by the following formula (6): 
       BO—M—Y) 3   (6) 
       (wherein M is Co or Ni and Y is an acid residue of a monocarboxylic acid having a carbon number of 2-21 or an aromatic group containing monocarboxylic acid having a carbon number of 2-21 provided that Ys are the same or different), a metal aluminate derivative represented by the following formula (7): 
       AlO—M—Y) 3   (7) 
       (wherein M is Co or Ni and Y is an acid residue of a monocarboxylic acid having a carbon number of 2-21 or an aromatic group containing monocarboxylic acid having a carbon number of 2-21 provided that Ys are the same or different), a cobalt, nickel or iron salt of dithiocarbamate or dithiocarbonate, a cobalt dithiocarbamate represented by the following formula (8):  
       
         
           
           
               
               
           
         
       
       (wherein R 8  is an alkyl group having a carbon number of 1-20 and Z is an oxygen atom or a sulfur atom provided that Zs are the same or partly different), a cobalt dithiophosphate represented by the following formula (9) or (10):  
       
         
           
           
               
               
           
         
       
       (wherein R 9  or R 10  is a hydrocarbon residue having a carbon number of 1-20 and Z is an oxygen atom or a sulfur atom provided that Zs are the same or partly different), and a molybdenum salt of a carboxylic acid represented by the following formula (11):  
       
         
           
           
               
               
           
         
       
       (wherein R 11  is an alkyl group having a carbon number of 1-20).  
     
     
         2 . A lubricant composition for steel filament comprising at least one compound represented by the following formula (12):  
       
         
           
           
               
               
           
         
       
       (wherein R 12 , R 13 , R 14  and R 15  are independently an alkyl group having a carbon number of 1-20, a cycloalkyl group having a carbon number of 3-20, a monovalent aromatic ring-containing group having a carbon number of 3-20 and, if necessary, containing at least one heteroatom selected from the group consisting of an oxygen atom, nitrogen atom and sulfur atom provided that at least one of R 12 , R 13 , R 14  and R 15  contains at least one of carboxyl group and/or ester compound thereof in its molecule, and x is an integer of 1 to 5)  
     
     
         3 . A lubricant composition according to  claim 1 , wherein A in the formula (1) is a hexamethylene group.  
     
     
         4 . A lubricant composition according to  claim 1 , wherein each of R 1  and R 2  in the formula (1) is a nitrogen-containing monovalent organic group containing at least one aromatic ring.  
     
     
         5 . A lubricant composition according to  claim 1 , wherein each of R 1  and R 2  in the formula (1) is a monovalent organic group having a group of bonding a carbon atom to a dithio group represented by ═N—C(═S)— group.  
     
     
         6 . A lubricant composition according to  claim 1 , wherein the compound of the formula (1) is α,ω-bis(N, N′-dihydrocarbylthiocarbamoyldithio) alkane represented by the following formula (13):  
       
         
           
           
               
               
           
         
       
       (wherein each of R 16  to R 19  is an alkyl group, an aryl group or an aralkyl group, provided that at least one of R 16  and R 17  and at least one of R 18  and R 19  are an aryl group having a carbon number of 6-20 or an aralkyl group having a carbon number of 7-20, and n is an integer of 2 to 10).  
     
     
         7 . A lubricant composition according to  claim 5 , wherein the compound of the formula (12) is 1,6-bis(N, N′-dibenzylthiocarbamoyldithiohexane.  
     
     
         8 . A lubricant composition according to  claim 1 , wherein a metal in the monoalkali metal salt of triazine thiol is selected from lithium, sodium and potassium.  
     
     
         9 . A lubricant composition according to  claim 7 , wherein at least one of boric acid and boric esters is added in addition to the monoalkali metal salt of triazine thiol.  
     
     
         10 . A lubricant composition according to  claim 8 , wherein the boric ester has 1 to 3 boron elements per one molecule and an alcohol residue having a carbon number of 1 to 4.  
     
     
         11 . A lubricant composition according to  claim 1 , wherein the thiadiazole compound is a dimercaptothiadiazole.  
     
     
         12 . A lubricant composition according to  claim 10 , wherein the dimercaptothiadiazole is 2,5-dimercapto-1,3,4-thiadiazole.  
     
     
         13 . A lubricant composition according to  claim 10 , wherein the dimer-captothiadiazole is a monosubstituted body selected from the group consisting of sodium salt, potassium salt, lithium salt, ammonium salt and zinc salt.  
     
     
         14 . A lubricant composition according to  claim 1 , wherein an inorganic acid in the bivalent or trivalent cobalt salt of the inorganic acid is at least one of hydrochloric acid, sulfuric acid, nitric acid and carbonic acid.  
     
     
         15 . A lubricant composition according to  claim 1 , wherein the Schiff base of the formula (2) is N, N′-disalycylidene ethylene diamine.  
     
     
         16 . A lubricant composition according to  claim 1 , wherein the cobalt alcholate is cobalt stearyl alcholate or cobalt nonylphenyl alcholate.  
     
     
         17 . A lubricant composition according to  claim 1 , wherein the cobalt complex of the formula (5) is at least one of cobalt acetylacetonate (II), cobalt acetylacetonate (III) and cobalt acetoanilide (II).  
     
     
         18 . A lubricant composition according to  claim 1 , wherein the cobalt borate derivative of the formula (6) is  
       
         
           
           
               
               
           
         
       
     
     
         19 . A lubricant composition according to  claim 1 , wherein the dithiocarbamate is cobalt bis(diethyldithiocarbamate)(II).  
     
     
         20 . A lubricant composition according to  claim 1 , wherein the dithiocarbonate is cobalt bis(o-ethyldithiocarbonate)(II).  
     
     
         21 . A lubricant composition according to  claim 1  wherein the dithiocarbonate is cobalt bis(o-ethyldithiocarbonate)(II).  
     
     
         22 . A lubricant composition according to  claim 1 , wherein the molybdenum salt of the formula (11) is molybdenum palmitate, molybdenum vehenate, molybdenum stearate, molybdenum palmitolate, molybdenum oleate or molybdenum linorate.  
     
     
         23 . A lubricant composition according to  claim 2 , wherein the compound of the formula (12) is a compound represented by the following formula (15):  
       
         
           
           
               
               
           
         
       
       (wherein R 12 , R 14  and x are the same as in the formula (12), and R 20 , R 22  are independently an alkylene group having a carbon number of 1-19, a cycloalkylene group having a carbon number of 3-19 or a bivalent aromatic ling-containing group having a carbon number of 3-19, direct bond, and R 21 , R 23  are independently hydrogen atom, methyl group or ethyl group).  
     
     
         24 . A steel filament having on its surface a layer of a lubricant composition as claimed in any one of  claims 1  to  23 .  
     
     
         25 . A rubber-steel filament composite body consisting of a rubber composition and a steel filament and having a layer of a lubricant composition as claimed in any one of  claims 1  to  23  at an interface therebetween.