Stable acid inhibitor formulations with improved performance, lower toxicity and minimal environmental issues

Abstract

Aqueous concentrates of non-toxic corrosion inhibitors, preferably storage-stable, useful in acidic cleaning solutions for cleaning the surfaces of metal that contacts food or potable water, the concentrates comprising at least one polymer, which may be protein-derived or synthetic; at least one iodine ion providing compound; an acidifier; and optionally, at least one anionic, nonionic or amphoteric surfactant; at least one coupling agent; and a pH adjuster; the concentrates being substantially free of nonylphenol derivatives and compounds containing elemental iodine and providing an improved acid inhibition and less foaming than similar compositions comprising nonylphenol derivatives and elemental iodine when mixed with aqueous acidic cleaners; acidic solutions prepared therefrom; and methods of their use.

1 . An aqueous, storage stable, corrosion inhibitor concentrate, comprising: 
 (A) at least one polymer, which may be protein-derived or synthetic;    (B) at least one iodine ion providing compound;    (C) optionally, at least one anionic, nonionic or amphoteric surfactant;    (D) optionally, at least one coupling agent;    (E) an acidifier; and    (F) a pH adjuster comprising at least one alkaline source;    wherein the aqueous corrosion inhibitor concentrate is storage stable.    
   
   
       2 . The aqueous corrosion inhibitor concentrate of  claim 1  wherein the acidifier comprises a polyprotic acid.  
   
   
       3 . The aqueous corrosion inhibitor concentrate of  claim 2  wherein the acidifier comprises a phosphoric acid.  
   
   
       4 . The aqueous corrosion inhibitor concentrate of  claim 1  wherein the acidifier and pH adjuster form a buffer system in the concentrate.  
   
   
       5 . The aqueous corrosion inhibitor concentrate of  claim 1  wherein (A) is a protein-derived polymer and (B) is a salt containing iodide anion.  
   
   
       6 . The aqueous corrosion inhibitor concentrate of  claim 1  comprising: 
 (A) about 1 to about 50% by weight of a gelatin hydrolysate;    (B) about 0.1 to about 15% by weight of ethylene diamine dihydroiodide;    (C) optionally, about 1 to about 20% by weight of at least one surfactant selected from the group consisting of anionic, nonionic, and amphoteric surfactants;    (D) optionally, at least one coupling agent;    (E) from about 0.5 to about 5% by weight of an acidifier; and    (F) an amount of pH adjuster comprising an alkaline source sufficient to give the concentrate a pH in the range of about 6.5 to about 3.    
   
   
       7 . The aqueous corrosion inhibitor concentrate according to  claim 6 , wherein the amount of gelatin hydrolysate is between about 10 to about 15% by weight; the amount of ethylene diamine dihydroiodide is between about 2 and about 8% by weight; the amount of surfactant is between about 2 to about 16% by weight; the amount of acidifier is between about 1.5 and 2.5% by weight and the pH adjuster comprising an alkaline source is present in an amount sufficient to give the concentrate a pH in the range of about 6.0 to about 3.5.  
   
   
       8 . The aqueous corrosion inhibitor concentrate of  claim 1  comprising less than 1.0 wt % nonylphenol derivatives and less than 0.1 wt % of compounds containing elemental iodine.  
   
   
       9 . An aqueous, nonylphenol-free, storage stable, corrosion inhibitor concentrate, comprising: 
 (A) at least one polymer, which may be protein-derived or synthetic;    (B) at least one iodine ion providing compound;    (C) at least one anionic, nonionic or amphoteric surfactant and/or a pH adjuster comprising at least one alkaline source;    (D) optionally, at least one coupling agent; and    (E) an acidifier;    said concentrate being substantially free of nonylphenol and nonyl phenol derivatives, wherein component (C) is present in an amount effective to render the aqueous corrosion inhibitor concentrate more storage stable, than a similar concentrate in the absence of component (C).    
   
   
       10 . The aqueous corrosion inhibitor concentrate of  claim 9  wherein (E) is a phosphoric acid.  
   
   
       11 . The aqueous corrosion inhibitor concentrate of  claim 9  having a pH of 2.7 to 6.  
   
   
       12 . The aqueous corrosion inhibitor concentrate of  claim 9  wherein (C) is a pH adjuster comprising at least one alkaline source.  
   
   
       13 . The aqueous corrosion inhibitor concentrate of  claim 12  comprising: 
 (A) about 1 to about 50% by weight of a gelatin hydrolysate;    (B) about 0.1 to about 15% by weight of ethylene diamine dihydroiodide;    (C) optionally, in addition to said pH adjuster, about 1 to about 20% by weight of at least one surfactant selected from the group consisting of anionic, nonionic, and amphoteric surfactants;    (D) optionally, at least one coupling agent; and    (E) from about 0.5 to about 5% by weight of an acidifier.    
   
   
       14 . An aqueous, corrosion inhibitor concentrate, comprising: 
 (A) at least one polymer, which may be protein-derived or synthetic;    (B) at least one iodine ion providing compound;    (C) optionally, at least one anionic, nonionic or amphoteric surfactant;    (D) optionally, at least one coupling agent; and    (E) an acidifier;    said concentrate comprising less than 1.0 wt % nonylphenol derivatives and less than 0.1 wt % of compounds containing elemental iodine, wherein said concentrate provides greater metal corrosion protection in acid cleaner solutions than a substantially identical concentrate containing nonylphenol derivatives and elemental iodine in greater amounts.    
   
   
       15 . The aqueous corrosion inhibitor concentrate of  claim 14  wherein (A) is a protein-derived polymer and (B) is a salt containing iodide anion.  
   
   
       16 . The aqueous corrosion inhibitor concentrate of  claim 15  comprising: 
 (A) about 1 to about 50% by weight of a gelatin hydrolysate;    (B) about 0.1 to about 15% by weight of ethylene diamine dihydroiodide;    (C) optionally, about 1 to about 20% by weight of at least one surfactant selected from the group consisting of anionic, nonionic, and amphoteric surfactants;    (D) optionally, at least one coupling agent; and    (E) from about 0.5 to about 5% by weight of an acidifier.    
   
   
       17 . The aqueous corrosion inhibitor concentrate of  claim 15  further comprising a pH adjuster comprising at least one alkaline source, said aqueous corrosion inhibitor concentrate having improved shelf life as compared to a substantially identical concentrate prepared in the absence of said alkaline source.  
   
   
       18 . An aqueous corrosion inhibited acid cleaning composition comprising: 
 (1) from about 1 to about 50% by weight of an acid;    (2) a corrosion inhibiting effective amount of an aqueous concentrate comprising: 
 (A) at least one polymer, which may be protein-derived or synthetic;  
 (B) at least one iodine ion providing compound;  
 (C) optionally, at least one anionic, nonionic or amphoteric surfactant;  
 (D) optionally, at least one coupling agent; and  
 (E) an acidifier;  
   in the absence of: nonylphenol derivatives and 
 compounds containing elemental iodine  
 and having a lower metal etch rate than similar compositions comprising nonylphenol derivatives and elemental iodine.  
   
   
   
       19 . The aqueous corrosion inhibitor concentrate of  claim 18  further comprising a pH adjuster comprising at least one alkaline source.  
   
   
       20 . The aqueous corrosion inhibited acid cleaning composition of  claim 18 , comprising a corrosion inhibiting effective amount of an aqueous concentrate comprising: 
 (i) about 1 to about 50% by weight of a gelatin hydrolysate;    (ii) about 0.1 to about 15% by weight of ethylene diamine dihydroiodide;    (iii) about 1 to about 20% by weight of at least one surfactant selected from the group consisting of anionic, nonionic, and amphoteric surfactants;    (iv) optionally, a coupling agent; and    (v) about 0.5 to about 5% by weight of an acidifier.