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.

Description

FIELD OF THE INVENTION [0001] This invention relates to corrosion inhibitors for use in acidic cleaning and pickling compositions. More particularly, the invention relates to storage-stable aqueous concentrates for non-toxic corrosion inhibitors useful in acidic pickling solutions for cleaning the surfaces of metal used in potable water wells, cooling towers, food process equipment and electrolysis membranes and other units holding, delivering or otherwise coming into contact with, food or potable water. BACKGROUND OF THE INVENTION [0002] Water wells containing potable water require periodic cleaning in order to remove scale from the well casings, well screens, pump bowls, etc. Typically, this scale is removed using an acid solution, generally a solution of hydrochloric acid. However, when such acid cleaning agents are used, several of the components forming the pumping mechanism are subject to attack by the acid, in particular, the well screen which is usually made of 304 stainless...

AI Technical Summary

Benefits of technology

[0015] In another embodiment of the invention the aqueous, corrosion inhibitor concentrate, comprises at least one polymer, which may be protein-derived or synthetic; at least one iodine ion providing compound; optionally, at least one anionic, nonionic or amphoteric surfactant; optionally, at least one coupling agent; and 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 amounts of nonylphenol phenol or its derivatives greater than or equal to 1.0 wt % and amounts compounds containing elemental iodine greater than 0.1 wt % . Preferably the polymer is a protein-derived polymer and the at least one iod

Problems solved by technology

However, when such acid cleaning agents are used, several of the components forming the pumping mechanism are subject to attack by the acid, in particular, the well screen which is usually made of 304 stainless steel, the well casing which is usually made of mild steel, and especially the pump bowl which is usually cast iron.

The hydrochloric acid is usually present in the cleaners in a concentration range of from 10 to 20% by weight, which, upon repeated use, can be quit

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