EP0017373B1 - Compositions stables utilisées comme inhibiteurs de corrosion et méthode d'inhibition de la corrosion en milieu aqueux - Google Patents

Compositions stables utilisées comme inhibiteurs de corrosion et méthode d'inhibition de la corrosion en milieu aqueux Download PDF

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Publication number
EP0017373B1
EP0017373B1 EP19800300811 EP80300811A EP0017373B1 EP 0017373 B1 EP0017373 B1 EP 0017373B1 EP 19800300811 EP19800300811 EP 19800300811 EP 80300811 A EP80300811 A EP 80300811A EP 0017373 B1 EP0017373 B1 EP 0017373B1
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Prior art keywords
water
soluble
polymer
zinc
aqueous medium
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EP19800300811
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EP0017373A1 (fr
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Gary Edwin Geiger
Roger Cletus May
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BetzDearborn Europe Inc
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Betz Europe Inc
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids

Definitions

  • the present invention is related to zinc-containing corrosion inhibitor treatments and treatment compositions.
  • the ability of zinc to inhibit the corrosion of ferrous metals is, indeed, well known.
  • soluble zinc salts are vital ingredients of many corrosion treatment programs.
  • U.S. 4,089,796 to Harris et al discloses a corrosion inhibiting composition comprising zinc and hydrolyzed polymaleic anhydride or soluble salt thereof and benzotriazole.
  • Other exemplary patents disclosing such zinc containing treatments are U.S. 3,432,428 to Wirth et al and U.S. 4,120,655 to Crambes et al.
  • the zinc could precipitate in other forms, for example, as zinc hydroxide or zinc silicate.
  • the solubility of the various salts depends on such factors as water temperature and pH and ion concentrations. Wirth et al states that although water temperatures can vary from 32° to 200°F (0 to 93,3°C). lower temperatures of 32° to 80°F (0 to 26,7°C) are preferred because "zinc tends to remain in solution better in cooler waters.” This patent further states that alkaline waters, particularly above about pH 7.5, are relatively undesirable because "the dissolved zinc tends to deposit out or drop out much more rapidly in alkaline water".
  • Crambes et al points out that zinc salts are unstable in neutral or alkaline water and will precipitate with phosphates. Thus, if any of these conditions are present, the aqueous medium becomes prone to zinc precipitation. Because of the formation of this zinc scale, many of the surfaces in contact with the aqueous medium will foul and the amount of effective (soluble) corrosion inhibitor present in the aqueous medium can be significantly reduced.
  • DE-A-2643242 (Kutita Water Industries Ltd) is directed to an improved method of inhibiting scale employing polymers containing a structural unit that is derived from a monomer having an ethylenically unsaturated bond and which has one or more carboxyl radicals, at least a part of said carboxyl radicals being modified as represented by the general formula:- wherein OA is an oxyalkylene radical having 2 to 4 carbon atoms, X is a hydroxyl radical, an alkoxy radical having 1 to 4 carbon atoms or a monovalent phosphate radical, X' is a bivalent phosphate radical and a is a positive integer.
  • conventional water treating agents are also required, such as polyphosphoric acids, phosphonic acids, orthophosphoric acid, organic phosphoric esters or polyvalent metal salts such as zinc or nickel salts, are also necessary.
  • polymers may be derived from acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, cinnomic acid or vinylbenzoic acid, preferably acrylic acid, methacrylic acid, maleic acid and fumaric acid.
  • the specific polymers illustrated are generally terpolymers composed of optional units such as esters of (meth)acrylic acid such as methyl(meth)acrylate, ethyl(meth)acrylate, butyl(meth)acrylate, diethylamino ethyl(meth)acrylate etc; styrene compounds such as styrene, methyl styrene, etc; fatty acid esters of vinyl alcohols, etc; etc.
  • esters of (meth)acrylic acid such as methyl(meth)acrylate, ethyl(meth)acrylate, butyl(meth)acrylate, diethylamino ethyl(meth)acrylate etc
  • styrene compounds such as styrene, methyl styrene, etc
  • fatty acid esters of vinyl alcohols, etc etc.
  • DE-A-2643242 illustrate the use of six terpolymers in conjunction either with one of the aforementioned phosphorus compounds or with both such a phosphorus compound and a zinc salt. These specifically exemplified terpolymers have been found not to be efficacious in retaining a corrosion-inhibiting amount of zinc in soluble form in an aqueous system.
  • the present invention is considered to have general applicability to any aqueous system where zinc precipitation is a problem, it is particularly useful in cooling water systems. Accordingly, the invention will hereinafter be described as it relates to cooling water systems.
  • a corrosion inhibitor treatment for metal surfaces exposed to an aqueous medium comprises (i) water-soluble zinc compound and (ii) a particular type of water-soluble polymer comprising moieties derived from an acrylic acid compound and moieties of hydroxylated lower alkyl acrylate (HAA).
  • the treatment could additionally comprise (iii) water-soluble orthophosphate and (iv) water-soluble chromate. It was discovered that, although the polymer demonstrated no significant activity alone as a corrosion inhibitor, when it was combined with a zinc-containing treatment the various ionic constituents of the treatment were unexpectedly retained in their soluble form and a corresponding increase in corrosion inhibiting activity was observed.
  • the present invention is accordingly also considered to be related to a method for inhibiting the formation of zinc scale in an aqueous medium.
  • AA acrylic acid compound
  • M is a water-soluble cation, e.g., NH 4 , alkali metal (
  • the polymers are considered, most broadly, to have a mole ratio of AA:HAA of from 1:4 to 36:1. This mole ratio is preferably 1:1 to 11:1, and most preferably 1:1 to 5:1.
  • the only criteria that is considered to be of importance with respect to mole ratios is that it is desirable to have a copolymer which is water-soluble. As the proportion of hydroxylated alkyl acrylate moieties increases, the solubility of the copolymer decreases. It is noted that, from an efficacy point of view, the polymers having a mole ratio of AA:HAA of 1:1 to 5:1 were considered the best.
  • the polymers could have a molecular weight of from 1,000 to 50,000 with from 2,000 to 6,000 being preferred.
  • the polymers utilized in accordance with the invention can be prepared by vinyl addition polymerization or by treatment of an acrylic acid or salt polymer. More specifically, acrylic acid or derivatives thereof or their water soluble salts, e.g., sodium, potassium, ammonium, etc. can be copclymerized with the hydroxy alkyl acrylate under standard copolymerization conditions utilizing free radical initiators such as benzoyl peroxide, azobisisobutyronitrile or redox initiators such as ferrous sulfate and ammonium persulfate. The molecular weights of the resulting copolymer can be controlled utilizing standard chain control agents such as secondary alcohols (isopropanol), mercaptans, halocarbons, etc. Copolymers falling within the scope of the invention are commercially available from, for example, National Starch Company.
  • the hydroxy alkyl acrylate can be prepared by the addition reaction between the acrylic acid or its derivatives or water soluble salts and the oxide of the alkyl derivative desired.
  • the preferred monomer of the present invention is the propyl derivative. Accordingly, to obtain the hydroxylated monomer, acrylic acid is reacted with propylene oxide to provide the hydroxypropyl acrylate monomer.
  • the polymers of the invention may also be prepared by reacting a polyacrylic acid or derivatives thereof with an appropriate amount of an alkylene oxide having from 2 to 6 carbon atoms such as ethylene oxide, propylene oxide and the like. The reaction takes place at the COOH or COM group of the moieties to provide the hydroxylated alkyl acrylate moiety.
  • the polymer prepared either by copolymerization of AA with hydroxy propyl acrylate (HPA) or reaction of AA with propylene oxide would be composed of units or moieties having the structural formulas: where M is as earlier defined.
  • Illustrative water-soluble zinc compounds which are considered to be suitable for use in accordance with the present invention are zinc oxide, zinc acetate, zinc chloride, zinc formate, zinc nitrate, zinc sulphate, zinc borate, zinc chromate, zinc dichromate, etc.
  • the treatment could further comprise orthophosphate.
  • orthophosphate could be provided as an actual addition product, e.g., sodium orthophosphate, or as a precursor compound such as complex inorganic phosphates, organic phosphates or organic phosphonates which revert to orthophosphate in the water.
  • orthophosphate as an actual addition are monosodium phosphate, and monopotassium phosphate. Any other water-soluble orthophosphate or phosphoric acid would also be considered to be suitable.
  • the complex inorganic phosphates are exemplified by sodium pyrophosphate, sodium tripolyphosphate, sodium tetraphosphate, sodium septaphosphate, sodium decaphosphate and sodium hexametaphosphate.
  • Either the corresponding potassium or ammonium salts or the corresponding molecularly dehydrated phosphoric acids such as metaphosphoric acid or pyrophosphoric acid are considered to be suitable.
  • the organic phosphonates are exemplified by aminotrimethylene phosphonic acid, hydroxyethylidene diphosphonic acid and the water-soluble salts thereof.
  • the amount of each constituent added to the cooling water will, of course, be an effective amount for the purpose and will depend on such factors as the nature and severity of the corrosion problem being treated, the temperature and pH of the cooling water and the type and amount of precipitation- prone ions present in the water.
  • active zinc ion As little as 0.5 parts of zinc per million parts (ppm) of cooling water are believed to be effective in certain instances, with 2 ppm being preferred. Based on economic considerations, the amount of zinc ion added could be as high as 25 ppm, with 10 ppm representing the preferred maximum.
  • active polymer As little as 0.5 ppm polymer is considered to be effective, while 2 ppm is the preferred minimum. Based on economic considerations, the polymer could be fed in amounts as high as 200 ppm, with 50 ppm representing the preferred maximum.
  • the orthophosphate or precursor compound thereof could be fed in an amount as low as 1 ppm, with 2 ppm representing the preferred minimum. Based on economic considerations, the maximum amount is considered to be 200 ppm. However, 50 ppm is considered to be the preferred maximum.
  • compositions according to the present invention could comprise on a weight basis:
  • compositions according to the present invention could comprise on a weight basis:
  • the preferred relative proportions are 5 to 85% zinc compound, 15 to 95% polymer and 5 to 85% orthophosphate.
  • the most preferred relative proportions are 10 to 60% zinc compound, 15 to 80% polymer and 10 to 60% orthophosphate.
  • the cooling water preferably will have a pH of 6.5 to 9.5. Since zinc precipitation problems most commonly occur at pH's above about 7.5, the most preferred pH range is from 7.5 to 9.5.
  • test water contained both zinc and orthophosphate ions, and the test procedures were the same as in Example 2 but for a few different steps as follows:
  • Tables 7-13 The results of these tests are reported below in Tables 7-13 in terms of ppm soluble zinc retained in solution. For purposes of comparison with untreated test solution, Table 7 should be compared with the results of Table 1 and Tables 8-13 should be compared with the results of Table 2.
  • Figure 1 are presented a series of graphs which contain comparisons of Table 7 with Table 1 in terms of soluble zinc remaining in solution after 24 hours vs. pH of the test water.
  • the lowermost graph represents a no treatment test wherein the zinc readily precipitates.
  • the higher graphs represent various test solutions to which have been added the noted AA/HPA polymers. The polymers were all considered to be efficacious in retaining soluble zinc in solution.
  • FIGS. 2-7 provide visual comparisons of respective ones of Tables 8-13 with Table 2.
  • Figure 2 compares Table 8
  • Figure 3 compares Table 9
  • Figure 4 compares Table 10
  • Figure 5 compares Table 11
  • Figure 6 compares Table 12
  • Figure 7 compares Table 13, all with Table 2 in terms of plots of soluble zinc remaining in solution after 24 hours vs. pH at various indicated treatment levels.
  • the line marked "No Treatment" in each figure represents the results of Table 2.
  • Corrosion rate measurement was determined by weight loss measurement. Prior to immersion, coupons were scrubbed with a mixture of trisodium phosphate-pumice, rinsed with water, rinsed with isopropyl alcohol and then air dried. Weight measurement to the nearest milligram was made. At the end of one day, a weighed coupon was removed and cleaned. Cleaning consisted of immersion into a 50% solution of HCI for approximately 20 seconds, rinsing with tap water, scrubbing with a mixture of trisodium-pumice until clean, then rinsing with tap water and isopropyl alcohol. When dry, a second weight measurement to the nearest milligram was made. At the termination of the tests, the remaining coupon was removed, cleaned and weighed.
  • the cooling water was prepared by first preparing the following stock solutions: Then, these solutions were combined using the following order of addition:
  • compositions made in accordance with the present invention are presented in Table 15 in terms of relative proportions (in weight percent) of the various constituents.
  • the water-soluble zinc compound was ZnSO 4 H 2 O and the orthophosphate was Na 3 PO 4 ⁇ 12H 2 O. Since calculations were rounded-off to two places, not all compositions added up to 100%. Stability is defined in terms of soluble constituents in solution after 24 hours at 12 ⁇ °F.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Preventing Corrosion Or Incrustation Of Metals (AREA)

Claims (24)

1. Composition comprenant une solution aqueuse d'un composé de zinc soluble dans l'eau, caractérisée en ce que cette solution contient aussi comme stabilisant un copolymère hydrosoluble comprenant des motifs d'un composé d'acide acrylique et des motifs d'un acrylate d'alkyle inférieur hydroxylé, motifs représentés par les formules:
Figure imgb0032
(dans lesquelles R représente l'hydrogène ou un alkyle en C, à C3; R, un groupe OH, NH2 ou OM, M étant un cation hydrosoluble, Rz est un alkylène en C2 à Cs, R3 l'hydrogène ou un alkyle en C, à C3 et le rapport molaire X:Y est compris entre 1:4 et 36:1), et caractérisée en outre en ce que, en poids, le composé de zinc représente de 1 à 95% et le polymère 5 à 99% du total des deux.
2. Composition selon la revendication 1 caractérisée en ce que le composé de zinc représente 4 à 85% en poids, et le polymère 15 et 96% en poids, du total des deux.
3. Composition selon la revendication 1 caractérisée en ce que le composé de zinc représente 5 à 70% en poids, et le polymère 30 à 95% en poids, du total des deux.
4. Composition selon l'une quelconque des revendications 1 à 3, caractérisée en ce que le polymère a une masse moléculaire de 1.000 à 50.000.
5. Composition selon la revendication 4, caractérisée en ce que le polymère a une masse moléculaire de 2.000 à 6.000.
6. Composition selon l'une quelconque des revendications 1 à 5, caractérisée en ce que le pH de la solution aqueuse est compris entre 6,5 et 9,5.
7. Composition selon l'une quelconque des revendications 1 à 6, caractérisée en ce que le rapport molaire x:y est compris entre 1:1 et 11:1.
8. Composition selon la revendication 7, caractérisée en ce que le rapport molaire x:y est compris entre 1:1 et 5:1.
9. Composition selon l'une quelconque des revendications 1 à 8, caractérisée en ce que le polymère est un copolymère d'acide acrylique ou d'un sel hydrosoluble de cet acide et d'acrylate d'hydroxypropyle.
10. Composition selon l'une quelconque des revendications 1 à 9, caractérisée en ce qu'elle contient aussi un orthophosphate hydrosoluble ou un précurseur de celui-ci.
11. Composition selon l'une quelconque des revendications 1 à 10, caractérisée en ce qu'elle comprend en outre un chromate hydrosoluble.
12. Composition selon la revendication 10, caractérisée en ce que, en poids, le composé de zinc représente 95%, l'orthophosphate ou son précurseur 1 à 95% et le polymère 5 à 99%, du total des trois.
13. Composition selon la revendication 10, caractérisée en ce que le composé de zinc représente 5 à 85%, l'orthophosphate ou son précurseur 5 à 85% et le polymère 15 à 95%, du total des trois.
14. Procédé pour diminuer le degré de corrosion de surfaces métalliques qui sont en contact avec un milieu aqueux ayant tendance à laisser précipiter du zinc, procédé caractérisée en ce que l'on ajoute au milieu aqueux, en plus d'un composé de zinc hydrosoluble, une proportion appropriée d'un polymère hydrosoluble tel que défini à l'une quelconque des revendications 1, 5, 6, 8, 9 et 10, le composé de zinc étant ajouté dans une proportion donnant 0,5 à 25 parties d'ion zinc par million de parties du milieu aqueux, et le polymère dans une proportion de 0,5 à 200 parties par million de parties du milieu aqueux.
15. Procédé selon la revendication 14, caractérisé en ce que le composé de zinc est ajouté dans une proportion donnant 2 à 10 parties d'ion zinc par million de parties du milieu aqueux, et le polymère dans une proportion de 2 à 50 parties par million de parties du milieu aqueux.
16. Procédé selon la revendication 14 ou 15, caractérisé en que le milieu aqueux est une eau de refroidissement.
17. Procédé selon l'une quelconque des revendications 14 à 16, caractérisé en ce que le pH de milieu aqueux est compris entre 6,5 et 9,5.
18. Procédé selon l'une quelconque des revendications 14 à 17, caractérisé en ce que l'on ajoute également au milieu aqueux un orthophosphate soluble dans l'eau ou un précurseur de celui-ci dans une proportion de 1 à 200 parties par million.
19. Procédé selon l'une quelconque des revendications 14 à 18, caractérisé en ce que le milieu aqueux comprend en outre un chromate soluble dans l'eau.
20. Procédé selon la revendication 18, dans lequel l'orthophosphate ou son précurseur est ajouté dans une proportion de 2 à 50 parties par million.
21. Procédé pour empêcher la formation d'incrustations de zinc dans un milieu aqueux contenant des ions zinc dans des conditions entraînant la formation d'incrustations, procédé caractérisé en ce que l'on ajoute au milieu aqueux une proportion appropriée à cette fin d'un polymère hydrosoluble tel que défini à l'une quelconque des revendications 1, 5, 6, 8, 9 et 10, polymère qui est ajouté dans une proportion de 0,5 à 200 parties par million de parties du milieu aqueux.
22. Procédé selon la revendication 21 caractérisé en ce que le milieu aqueux est une eau de refroidissement.
23. Procédé selon la revendication 22 caractérisé en ce que le milieu aqueux contient des ions phosphate qui ont été ajoutés pour le traitement.
24. Procédé selon l'une quelconque des revendications 21 à 23, caractérisé en ce que les incrustations de zinc comprennent de l'hydroxyde ou du phosphate de zinc ou les deux à la fois.
EP19800300811 1979-04-05 1980-03-18 Compositions stables utilisées comme inhibiteurs de corrosion et méthode d'inhibition de la corrosion en milieu aqueux Expired EP0017373B1 (fr)

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US2734679A 1979-04-05 1979-04-05
US27346 1979-04-05
US8907679A 1979-10-29 1979-10-29
US89076 1979-10-29

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EP (1) EP0017373B1 (fr)
AU (1) AU533619B2 (fr)
CA (1) CA1118590A (fr)
DE (1) DE3069957D1 (fr)
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SG (1) SG27687G (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8765656B2 (en) 2006-08-02 2014-07-01 Ch2O Incorporated Disinfecting/mineral treating composition and methods comprising a chlorite or chlorate salt

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4303568A (en) * 1979-12-10 1981-12-01 Betz Laboratories, Inc. Corrosion inhibition treatments and method
US5453416A (en) * 1986-07-30 1995-09-26 W. R. Grace & Co.-Conn. Composition and method for controlling phosphonates tending to precipitate metal ions in water
US4836933A (en) * 1987-01-16 1989-06-06 National Starch And Chemical Corporation Water treatment polymer
US6054266A (en) * 1987-12-21 2000-04-25 Applied Biosystems, Inc. Nucleic acid detection with separation
US6350410B1 (en) * 1995-04-13 2002-02-26 Ch20 Incorporated Method and composition for inhibiting biological fouling in an irrigation system

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DE2154737A1 (de) * 1971-11-04 1973-05-24 Degussa Mittel und verfahren zur rostschutzbehandlung
US4089796A (en) * 1971-12-10 1978-05-16 Ciba-Geigy Corporation Treatment of water or aqueous systems
GB1374270A (en) * 1971-12-10 1974-11-20 Ciba Geigy Ag Polymaleic anhydride compositions and their use
FR2198106A1 (en) * 1972-09-04 1974-03-29 Rhone Progil Corrosion and scale prevention in cooling systems - using phosphates, zinc salts and acrylic polymers
US3885914A (en) * 1973-06-04 1975-05-27 Calgon Corp Polymer-zinc corrosion inhibiting method
US4029577A (en) * 1975-11-17 1977-06-14 Betz Laboratories, Inc. Polymers for use in water treatment
DE2643422A1 (de) * 1976-09-21 1978-03-30 Kurita Water Ind Ltd Wasserbehandlungsmittel und verfahren zur behandlung von wasser

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8765656B2 (en) 2006-08-02 2014-07-01 Ch2O Incorporated Disinfecting/mineral treating composition and methods comprising a chlorite or chlorate salt

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DE3069957D1 (en) 1985-02-28
NZ193166A (en) 1982-09-07
EP0017373A1 (fr) 1980-10-15
SG27687G (en) 1988-05-20
AU533619B2 (en) 1983-12-01
CA1118590A (fr) 1982-02-23
AU5650880A (en) 1980-10-09

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