Nalco Chemical Company

Guy A Crucil

John E Hoots

Dodd W Fong

Donald A Johnson

Laura J Blaser

Daniel A Meier

Ellen L Johnson

New zinc stabilizing polymers containing at least 5 mole percent of a monomer represented by the structure: ##STR1## wherein: R is independently, at each occurrence, chosen from H and lower (C.sub.1 -C.sub.4) alkyl groups;

Zinc stabilization with modified acrylamide based polymers and corrosion

A process for inhibiting the corrosion of metals in contact with aqueous systems is provided which process comprises adding to such systems an effective amount of a water treatment composition comprising a source of molybdate ion and a water-soluble polymer containing pendant amide functionality.

Molybdate-containing corrosion inhibitors

New zinc stabilizing polymers containing at least 5 mole percent of a monomer represented by the structure: ##STR1## wherein: R is independently, at each occurrence, chosen from H and lower (C.sub.1 -C.sub.4) alkyl groups; R' is a hydrocarbonaceous bridging group containing from 1-12 carbon atoms; X is chosen from --SO.sub.3 M, --OH, --COOM groups or mixtures thereof, M is hydrogen or some other cation species; and n ranges from 1-10, are described. Also, the use of these polymers in combination with zinc salts, and in further combination with phosphate salts, to inhibit corrosion of iron containing metals, and other metals, when these metals are exposed to industrial waters is demonstrated. Deposit control or scale inhibition on these metals exposed to industrial waters is also observed.

A method of preventing corrosion and scale formation on metals exposed to industrial recirculating waters having a pH ranging between about 7.0 to about 9.5, which consists essentially of adding to said industrial recirculating waters an effective amount of a combination of a water-soluble zinc salt, a nitrogen-containing N-alkylated acrylamide zinc complexing polymer and an orthophosphate ion source, wherein:

Branched alkyl acrylamide types of polymer-zinc corrosion inhibitor

Water-soluble zinc:polymer complexes of nitrogen-containing polymers are useful in preventing corrosion in aqueous recirculating systems operating within the pH range of 7.0-9.5, when combined with orthophosphate ion sources.

A method for inhibiting corrosion in industrial cooling waters which contain hardness and a pH of at least 6.5, comprising using a water-soluble inorganic phosphate capable of inhibiting corrosion in an aqueous alkaline environment and a co- or terpolymer of acrylic acid and certain substituted acrylamides such as t-butyl acrylamide. A water-soluble organic phosphonate capable of inhibiting corrosion in an alkaline environment may be used as an adjunct for the phosphate.

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Bloomingdale, IL, United States of America

Guy A Crucil