Dot 4 brake fluids

Abstract

A brake fluid comprises a) from 10 to 50, preferably from 20 to 40, % by weight of diethylene glycol and/or dipropylene glycol and b) from 50 to 90, preferably from 60 to 80, % by weight of one or more monoalkyl ethers of (poly)ethylene glycol and/or (poly)propylene glycol. The novel fluids are in particular free of borate and, owing to the low hygroscopicity, are suitable for use in regions of high relative humidity.

1 - 12 . (canceled)  
   
   
       13 . A brake fluid comprising 
 a) from 10 to 50% by weight of diethylene glycol and/or dipropylene glycol and    b) from 50 to 90% by weight of one or more monoalkyl ethers of (poly)ethylene glycol and/or (poly)propylene glycol.    
   
   
       14 . The brake fluid as claimed in  claim 13 , which contains no boric acid esters.  
   
   
       15 . The brake fluid as claimed in  claim 13 , which contains no polyalkylene glycol dialkyl ethers.  
   
   
       16 . The brake fluid as claimed in  claim 13 , wherein diethylene glycol is used as component a).  
   
   
       17 . The brake fluid as claimed in  claim 13 , wherein, in component b), the glycol is at least one selected from the group consisting of monoethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, hexaethylene glycol, monopropylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, pentapropylene glycol and hexapropylene glycol.  
   
   
       18 . The brake fluid as claimed in  claim 13 , wherein, in component b), the alkyl radical is selected from linear and branched C 1 -C 6 -alkyl radicals.  
   
   
       19 . The brake fluid as claimed in  claim 13 , wherein component b) is at least one selected from the group consisting of methyldiethylene glycol, methyltriethylene glycol, methyltetraethylene glycol and butyltriethylene glycol.  
   
   
       20 . The brake fluid as claimed in  claim 13 , wherein reaction products of ethylene oxide and/or propylene oxide and/or butylene oxide with water or diols, are also present.  
   
   
       21 . The brake fluid as claimed in  claim 13 , wherein from 0.01 to 10, % by weight of one or more corrosion inhibitors are present.  
   
   
       22 . The brake fluid as claimed in  claim 13 , wherein the corrosion inhibitors are at least one selected from the group consisting of 1H-1,2,3-benzotriazole, 1H-1,2,3-tolutriazole, hydrogenated 1H-1,2,3-tolutriazole, benzimidazole and/or derivatives thereof, alkali metal salts of phosphoric acid and phosphorous acid, fatty acids, and alkali metal salts thereof, esters of phosphoric acid and of phosphorous acid, mono- and dialkylamines which may be ethoxylated and salts thereof with mineral and fatty acids, alkanolamines which may be ethoxylated, cyclohexylamine and nitro aromatics.  
   
   
       23 . The brake fluid as claimed in  claim 13 , which complies with the following specification values (DOT 4):  
     
       
         
               
               
               
             
                   
                   
               
                   
                   
               
                   
                 ERBP: 
                 ≧230° C. 
               
                   
                 Wet ERBP: 
                 ≧155° C. 
               
                   
                 Viscosity at −40° C.: 
                 ≦1800 mm 2 /s 
               
                   
                   
               
                   
                   
               
           
              
              
             
             
              
              
              
              
              
             
          
         
       
     
   
   
       24 . The brake fluid as claimed in  claim 13  wherein the brake fluid is utilized as a brake fluid in motor vehicles.  
   
   
       25 . A motor vehicle brake system comprising the brake fluid as claimed in  claim 13.