Hydraulic fluids with improved anti-corrosion properties

Abstract

Hydraulic fluids, in particular brake fluids for motor vehicles, having improved corrosion protection, comprising (a) from 0.005 to 0.125% by weight of 1H-1,2,4-triazole, and (b) from 0 to 10% by weight of one or more further corrosion inhibitors, where, on concomitant use of 1H-1,2,3-benzotriazole and/or 1H-1,2,3-tolutriazole and/or derivatives thereof, the weight ratio between 1H-1,2,4-triazole and the said 1H-1,2,3-triazoles must be greater than 4:1.

We claim:  
     
         1 . A hydraulic fluid having improved corrosion protection, comprising 
 (a) from 0.005 to 0.125% by weight of 1H-1,2,4-triazole, and    (b) from 0 to 10% by weight of one or more further corrosion inhibitors, where, on concomitant use of 1H-1,2,3-benzotriazole and/or 1H-1,2,3-tolutriazole and/or derivatives thereof, the weight ratio between 1H-1,2,4-triazole and said 1H-1,2,3-triazoles must be greater than 4:1.    
     
     
         2 . A hydraulic fluid as claimed in  claim 1 , comprising from 0.005 to 0.08% by weight of component (a).  
     
     
         3 . A hydraulic fluid as claimed in  claim 1  or  2 , comprising component (a) as the only triazole-based corrosion inhibitor.  
     
     
         4 . A hydraulic fluid as claimed in  claim 1  or  2 , comprising, as component (b), from 0.001 to 0.5% by weight of one or more compounds from the group consisting of benzimidazole, hydrogenated 1H-1,2,3-tolutriazole, purine, adenine, 6-chloropurine, 2,6-dichloropurine, 6-methoxypurine, 1H-1,2,3-triazolo(4,5-b)pyridine, 6-histaminopurine and 6-furfurylaminopurine, and, if desired, further corrosion inhibitors other than (a).  
     
     
         5 . A brake fluid for motor vehicles, comprising, as corrosion inhibitors, components (a) and, if desired, (b) as claimed in any one of  claims 1  to  4 .  
     
     
         6 . A brake fluid for motor vehicles as claimed in  claim 5 , furthermore comprising, besides components (a) and, if desired, (b), from 0.1 to 97% by weight of one or more polyglycol ethers and/or boric acid esters thereof.  
     
     
         7 . A brake fluid for motor vehicles as claimed in  claim 5  or  6 , furthermore comprising, besides components (a) and, if desired, (b), from 0.1 to 50% by weight of one or more polyglycols.