Inhibiting the corrosive properties of liquid cleaning agents containing hypochlorite

Abstract

A process for reducing the corrosive action of hypochlorite on metal surfaces in hypochlorite-containing aqueous liquid cleaning agents by the use of a combination of alkali hydroxide, alkali silicate, and alkyl(alkoxy) n sulfate, where n=0.5 to 10.

1 . A process for reducing the corrosiveness of hypochlorite on a metal surface comprising the step of contacting the metal surface with an aqueous liquid cleaning agent comprising hypochlorite, alkali hydroxide, alkali silicate, and alkyl(alkoxy) n  sulfate, where n=0.5 to 10. 
     
     
         2 . The process according to  claim 1 , wherein the metal surface is a steel surface. 
     
     
         3 . The process according to  claim 1 , wherein the cleaning agent contains 0.5 wt % to 10 wt % alkali hypochlorite. 
     
     
         4 . The process according to  claim 1 , wherein the cleaning agent contains from more than 0 wt % to 5 wt % alkali hydroxide. 
     
     
         5 . The process according to  claim 1 , wherein the cleaning agent contains from more than 0 wt % to 5 wt % alkali silicate. 
     
     
         6 . The process according to  claim 1 , wherein the cleaning agent contains from more than 0 wt % to 5 wt % alkyl(alkoxy) n  sulfate. 
     
     
         7 . The process according to  claim 1 , wherein the cleaning agent contains alkyl(alkoxy) n  sulfate having a C 8-18  alkyl group, —OCH 2 CH 2 —, and/or —OCHCH 3 CH 2  alkoxy group(s), in which n is a number from 1 to 6 and that comprise an alkali metal counterion for the sulfate group. 
     
     
         8 . The process according to  claim 1 , wherein the alkali hydroxide is sodium hydroxide, the alkali silicate is sodium silicate, and/or the alkali metal counterion is the sodium ion. 
     
     
         9 . The process according to  claim 1 , wherein the cleaning agent contains up to 5 wt % additional bleach-stable surfactant. 
     
     
         10 . The process according to  claim 1 , wherein the cleaning agent additionally contains 0.01 wt % to 2 wt % alkylphosphonic acid, phosphonate, amine oxide phosphonic acid, polyacrylic acid comprising phosphono groups, and/or alkali salt of one or both of said acids, and/or 0.1 wt % to 2 wt % carbonate. 
     
     
         11 . A method for cleaning metal surfaces comprising the step of applying to the surfaces a hypochlorite-containing aqueous liquid cleaning agent that contains a combination of alkali hydroxide, alkali silicate, and alkyl(alkoxy) n  sulfate, where n=0.5 to 10. 
     
     
         12 . A cleaning agent for metal surfaces, said agent comprising 0.5 wt % to 10 wt % sodium hypochlorite, more than 0 wt % to 5 wt % alkali hydroxide, more than 0 wt % to 5 wt % alkali silicate and alkyl (alkoxyl) n  sulfate where n=0.5 to 10. 
     
     
         13 . The agent according to  claim 12 , said agent comprising 2 wt % sodium hypochlorite, 1.5 wt % sodium hydroxide, 3 wt % Na—C 14/16  alkyl (ethoxy) 2  sulfate and 2 wt % sodium silicate. 
     
     
         14 . The agent according to  claim 12 , said agent further comprising more than 0 wt % to 5 wt % bleach stable surfactant. 
     
     
         15 . The agent according to  claim 14 , wherein the surfactant is at least one betaine of the general formula (I): 
       
         
           
           
               
               
           
         
       
       in which R 1  is an alkyl or alkenyl group having 6 to 22 carbon atoms or an R 4 CO—NH (CH 2 ) n  group, R 2  is hydrogen or an alkyl group having 1 to 4 carbon atoms, R 3  is hydrogen or an alkyl group having 1 to 4 carbon atoms, R 4  is an alkyl or alkenyl group having 6 to 22 carbon atoms, m is a number from 1 to 6, and n is a number from 1 to 3. 
     
     
         16 . The cleaning agent according to  claim 11 , said agent further comprising a sequestering agent. 
     
     
         17 . The cleaning agent according to  claim 16 , wherein the sequestering agent is at least one compound according to the general formula (II) 
       
         
           
           
               
               
           
         
       
       in which R 5  is hydrogen, a —(CH 2 ) x (CHCH 3 ) y —NH 2 ->O group, or an alkali metal, x is a number from 1 to 4, and y is 0 or 1. 
     
     
         18 . The agent according to  claim 11 , said agent further comprising 0.1 wt % to 2 wt % of a carbonate. 
     
     
         19 . The agent according to  claim 18 , wherein the carbonate is an alkali carbonate. 
     
     
         20 . The agent according to  claim 11 , said agent further comprising one or more bleach-stable dyes or odorants.