EP0065609B1 - Corrosion inhibiting composition, process for its preparation and its use in the field of metal surface protection - Google Patents

Corrosion inhibiting composition, process for its preparation and its use in the field of metal surface protection Download PDF

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EP0065609B1
EP0065609B1 EP81400861A EP81400861A EP0065609B1 EP 0065609 B1 EP0065609 B1 EP 0065609B1 EP 81400861 A EP81400861 A EP 81400861A EP 81400861 A EP81400861 A EP 81400861A EP 0065609 B1 EP0065609 B1 EP 0065609B1
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French (fr)
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EP0065609A1 (en
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Francis Moran
Sylvain Rocher
Michel Duprat
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Union Chimique Et Industrielle De L'ouest Sa SA
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Union Chimique Et Industrielle De L'ouest Sa SA
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Priority to DE8181400861T priority patent/DE3172413D1/en
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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
    • C23F11/10—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 using organic inhibitors

Definitions

  • the present invention relates, as a new industrial product, to a corrosion-inhibiting composition. It also relates to its preparation process and its application in the field of protecting metal surfaces, in particular with respect to corrosion in the presence of water in liquid or vapor form.
  • anti-scaling means (hereinafter designated "B") which are in particular obtained by polymerization or copolymerization from a monomer having a unit (where R o is a nitrile, amide, imide, carboxylic acid or carboxylate radical).
  • R o is a nitrile, amide, imide, carboxylic acid or carboxylate radical.
  • anti-tartar substances have been recommended in particular in FR-A-2178808, FR-A-2 379 616 and US-A-4 048 066.
  • a corrosion inhibiting composition intended to be introduced into an underground formation from which hydrocarbon and / or aqueous fluids are pumped, and which comprises a diamine (namely an alkyl (in C s _C 3o ) -amino-propyleneamine) and a polyelectrolyte of the polyacrylic acid, polyacrylate or polyacrylamide type (preferably a hydrolyzed polyacrylamide with 20 to 40% of non-hydrolyzed amide groups).
  • a diamine namely an alkyl (in C s _C 3o ) -amino-propyleneamine
  • a polyelectrolyte of the polyacrylic acid, polyacrylate or polyacrylamide type preferably a hydrolyzed polyacrylamide with 20 to 40% of non-hydrolyzed amide groups.
  • diamine and the polyelectrolyte are combined with other ingredients (strong acid medium, a surfactant, an amide, an alcohol, in particular isopropanol) so that their mixture be effective.
  • ingredients strong acid medium, a surfactant, an amide, an alcohol, in particular isopropanol
  • the amines of formula I can be used as they can be obtained commercially, alone or mixed together, in their pure or technical forms.
  • polyamines sold which are suitable mention may be made in particular of the products known under the brand names DUO-MEEN, DINORAM, TRINORAM, POLYRAM, LILA-MIN, and CEMULCAT which contain at least one polyamine I having a molecular weight greater than or equal to 228.
  • DINORAM 0 which contains approximately 75% by dry weight of oleylamino-propyleneamine, 9% by dry weight of stearylamopropyleneamine and 6% by dry weight of hexadecylaminopropyleneamine
  • DINORAM S which contains approximately 43% by dry weight of stearylaminopropyleneamine, 28% by dry weight of oleylaminopropyleneamine and 28% by dry weight of hexadecylaminopropyleneamine, these products being marketed by CECA.
  • the polymeric organic polyelectrolytes have a molecular weight greater than or equal to about 150 and preferably a molecular weight greater than or equal to 300.
  • the higher molecular weight can be high, and can be of the order of 2,000,000 or more.
  • polyelectrolytes of formula II having a molecular weight of between 800 and 1000 (in particular polymaleic acids marketed under the brand name of BELCLENE by the company CIBA-GEIGY), polyelectrolytes of formula IV having a high molecular weight of the order of approximately 5 ⁇ 10 5 to approximately 10 6 (in particular to polyethyleneimines sold under the brand name of SEDIPUR by the company BASF), to polyelectrolytes of formula V having a high molecular weight of the order of approximately 5 ⁇ 10 5 to approximately 10 6 (in particular to products of the polyvinylammonium type marketed under the brand name of PRIMAFLOC by the company ROHM & HAAS), to polyelectrolytes of formula VI having an average molecular weight of the order from about 10 4 to about 10 5 (in particular to acrylic acid-styrenesulfonic acid copolymers and to their salts with alkali metals such as Na and K, sold under the brand name of SL
  • the most advantageous substances according to the invention are the products of formula II.
  • polyelectrolytes corresponding to formulas II to VII above may be chemically pure products, or technical products normally manufactured by industry and marketed in liquid or pasty form, or also in the form of aqueous solutions at all concentrations, without the choice of one of these forms of presentation may constitute any limitation to the present invention. However, we generally prefer for commercial reasons and for convenience. polyelectrolytes commercially available in the form of aqueous solutions.
  • composition according to the invention will contain (a) 1 to 8 parts by dry weight of polyamine and b) 2 to 9 parts by dry weight of polyelectrolyte, the weight ratio a / b then being between 1: 9 and 4: 1.
  • the process for preparing the corrosion inhibiting composition is carried out according to a method known per se which consists in mixing one or more polyamines with one or more polyelectrolytes.
  • a method known per se which consists in mixing one or more polyamines with one or more polyelectrolytes.
  • use is made of a process which is characterized in that the selected polyamine or polyamines are introduced into the liquid state, by sufficient heating, which are gradually introduced, with moderate stirring. , or bright, as the case may be, in an aqueous solution of the polyelectrolyte (s) chosen and previously heated to a temperature lower than that of the polyamine.
  • the composition which is obtained may be in the form of a gel, or a paste, or a wax.
  • the composition according to the invention is insoluble or sparingly soluble in water, the solubility in water being much less than 10 g / l.
  • the polyamine (s) will be melted at a temperature between approximately 30 and approximately 85 ° C. and poured into the polyelectrolyte (s) brought to a temperature between approximately 15 and approximately 60 ° C.
  • metal surfaces to be protected are at low temperatures, more precisely at temperatures below 60 ° C., such as the metal surfaces of air humidifiers, condensers, chilled water networks, it will be preferable to choose those, among the polyelectrolytes corresponding to the formulas II to VII above, and those, among the aliphatic polyamines corresponding to the general formula 1 above, which give, in mixture, compositions having softening points as low as possible.
  • mixtures with higher softening points will be preferred as corrosion inhibitors with respect to metal surfaces subjected to high temperatures, such as for example those constituting the tubes of steam boilers, or superheaters, or else those constituting the cooling circuits of the ovens of the metallurgical and steel industries.
  • the pasty or gelled compositions produced according to the invention can be introduced using a positive displacement piston pump, as is commercially available, either as is in the water of industrial or real estate circuits. to be protected, either still previously emulsified, or dispersed in a larger amount of water using one or more surface-active substances of commerce and known to those skilled in the art as capable of dispersing polyamines oily.
  • the amounts of substances with surface-active properties used for this purpose depend on the commercial aspect which it is desired to give to such dispersions and should not constitute any limitation to the present invention.
  • This composition constitutes an excellent corrosion inhibitor, as the experiments set out below demonstrate.
  • the test piece is in the form of a cylinder with a cross-section of 1 cm 2 , screwed onto an axis of rotation, the assembly being coated with a tight heat-shrinkable sheath. It is made of steel (grade XC 35).
  • each specimen is polished with abrasive paper (with silicon carbide of grade 80), rinsed with water then cleaned and degreased in alcohol under ultrasound and finally dried with hot pulsed air.
  • abrasive paper with silicon carbide of grade 80
  • the test cell consists of a 300 ml "PYREX” glass container provided with an opening for the introduction of the rotating test piece.
  • the rotating specimen is introduced into the aggressive medium and remains in contact with said medium for 24 hours. Its rotation speed is 1000 revolutions / minute.
  • the aggressive medium consists of the softened water of Table III below. The amount used is 250 ml.
  • the corrosion products adhering to the test piece are ultrasonically scoured to pass them through the aggressive medium.
  • the resulting aqueous medium is collected and to have a homogeneous solution, the corrosion products are dissolved by acidification with HCl.
  • the content of the various cations present in trace amounts in the resulting solution is determined by atomic absorption spectrometry.
  • the iron content in the case of a steel test piece (grade XC 35) is directly proportional to the intensity of the corrosive effect.
  • the presence of dissolved iron in the solution results in the apparatus by the appearance of a peak of increasing height with the iron content.
  • the ratio of peak heights (expressed in cm) with and without inhibitor makes it possible to deduce the inhibitory efficiency E (%) according to the relationship (where h and h ° respectively represent the heights of the peaks with and without inhibitors).
  • the equipment and the potocole relating to the determination of the weight loss of the test pieces by a direct measurement of the gravimetric type are those described in the aforementioned document EP-A-10,485.
  • Tables IV and V demonstrate the remarkable inhibitory properties of the compositions according to the invention, since no corrosion could have been greater than 55 ⁇ m / year for the steel, 10 ⁇ m / year for the copper and 18 ⁇ m / year for aluminum.
  • compositions according to the invention are effective corrosion inhibitors, that they can be used for any metallic surface whatever the water (raw water, softened water , salt water), and that their inhibitory power is greater than that of their constituents used alone.

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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)
  • Compositions Of Macromolecular Compounds (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

Abstract

1. A corrosion inhibiting composition for metallic surfaces in contact with water, containing at least one polyamine component and at least one polyelectrolyte component, said composition being characterized in that it comprises in association a) a substance selected from the polyamines having a molecular weight higher than or equal to 228 and corresponding to the general formula R NH-(CH2 )m n (in which R represents a saturated or unsaturated C12 -C22 hydrocarbon aliphatic radical, m is an integer of between 2 and 8 inclusive, and n is an integer of between 1 and 7 inclusive, the R, m and n values being such that the molecular weight of said polyamines is higher than or equal to 228) and mixtures thereof ; and b) a polymeric organic polyelectrolyte selected from (i) the derivatives of the polymaleic type corresponding to the general formula see diagramm : EP0065609,P11,F1 (wherein R3 and R4 , which may be identical or different, each represent a hydrogen atom or a C1 -C4 alkyl group, R1 is H, C1 -C4 alkyl, Na**+ , K**+ or NH4 **+ , and n is an integer higher than or equal to 2) ; (ii) the derivatives of the styrene-maleic type having an unit see diagramm : EP0065609,P11,F2 (wherein R1 is defined as indicated above, n2 is an integer higher than or equal to 1, and n3 and n4 , which may be identical or different, each represent an integer higher than or equal to 1, one of the n3 and n4 being able, in the case of a sequenced copolymer, to represent 0) ; (iii) the derivatives of the polyethyleneimine type corresponding to the general formula : see diagramm : EP0065609,P11,F3 (wherein R2 is H or C1 -C4 alkyl, n1 is defined as indicated above, X**- represents a F**- , Cl**- , Br**- or I**- halogenide ion) ; (iv) the derivatives of the polyvinylammonium type of the general formula see diagramm : EP0065609,P11,F5 (wherein R2 , n1 and X**- are defined as indicated above) ; (v) the copolymer derivatives of the acrylicstyrenesulfonic type having an unit see diagramm : EP0065609,P12,F1 (wherein R1 , R2 , n2 , n3 and n4 are defined as indicated above) ; (vi) the derivatives of the lignosulfonate type corresponding to the general formula see diagramm : EP0065609,P12,F2 (wherein R1 and n1 are defined as indicated above) ; and (vii) mixtures thereof.

Description

La présente invention concerne en tant que produit industriel nouveau, une composition inhibitrice de corrosion. Elle concerne également son procédé de préparation et son application dans le domaine de la protection des surfaces métalliques, notamment vis-à-vis de la corrosion en présence d'eau sous forme liquide ou vapeur.The present invention relates, as a new industrial product, to a corrosion-inhibiting composition. It also relates to its preparation process and its application in the field of protecting metal surfaces, in particular with respect to corrosion in the presence of water in liquid or vapor form.

On sait que toute surface métallique d'usage industriel courant, et, d'une manière générale, tout matériel composé d'un ou de plusieurs métaux, tels le fer et ses alliages, notamment l'acier galvanisé, le cuivre et ses alliages, l'aluminium et ses alliages, pour ne citer que les plus employés, sont soumis, au contact de l'eau, à des transformations gênantes, généralement appelées «phénomènes de corrosion».It is known that any metallic surface of current industrial use, and, in general, any material composed of one or more metals, such as iron and its alloys, in particular galvanized steel, copper and its alloys, aluminum and its alloys, to name only the most used, are subjected, in contact with water, to troublesome transformations, generally called "corrosion phenomena".

On sait de plus que les différences entre les potentiels respectifs de dissolution des divers métaux conduisent, au contact de l'eau, à la formation de couples électrochimiques aggravant encore les phénomènes de dégradation préférentielle de certains métaux par rapport à d'autres. Ces phénomènes de corrosion sont d'autant plus importants et cumulatifs que les apports d'eau nouvelle sont eux-mêmes fréquents, ou importants en quantités. De plus compte-tenu de l'accroissement des besoins en eaux de diverses qualités, ces dernières voient leurs caractéristiques varier assez fortement, en des temps parfois très courts, notamment en ce qui concerne leurs teneurs en gaz dissous, ou combinés, en sels corrosifs, ou en sels précipitables sous formes incrustantes.We also know that the differences between the respective dissolution potentials of the various metals lead, on contact with water, to the formation of electrochemical couples, further aggravating the phenomena of preferential degradation of certain metals over others. These corrosion phenomena are all the more important and cumulative as the additions of new water are themselves frequent, or significant in quantities. In addition, given the increase in the need for water of various qualities, the latter see their characteristics vary quite strongly, sometimes in very short times, in particular as regards their contents of dissolved gas, or combined, of corrosive salts. , or in precipitable salts in encrusting forms.

Dans le domaine de la protection des surfaces métalliques en contact avec l'eau, en fait une distinction entre les moyens inhibiteurs de corrosion et les moyens anti-tartre. Les premiers préviennent la dégradation, les seconds empêchent le dépôt de tartre en formant un revêtement protecteur.In the field of protection of metallic surfaces in contact with water, makes a distinction between corrosion inhibiting means and anti-scale means. The former prevent degradation, the latter prevent scale deposits by forming a protective coating.

On sait que, dans le passé, on a recommandé d'utiliser des polyamines (désignées ci-après «A») en tant qu'agents inhibiteurs de corrosion, notamment dans FR-A-1 435 023, US-A-3 069 225, US-A-2857333, et NL-C-100963. Or il se trouve que les polyamines conduisent à une inhibition insuffisante de la corrosion par l'eau des métaux, en ce sens que la perte d'épaisseur des surfaces métalliques que l'on a voulu protéger est de l'ordre de 80 à 150µm/an dans les meilleures conditions d'emploi. Il se trouve également que, si les polyamines utilisées seules ont un effet anti-corrosif aux doses élevées (c'est-à-dire aux doses supérieures ou égales à 100 ppm), elles accélèrent la corrosion aux doses inférieures (de l'ordre de la dizaine de ppm notamment).It is known that, in the past, it has been recommended to use polyamines (hereinafter designated "A") as corrosion-inhibiting agents, in particular in FR-A-1,435,023, US-A-3,069 225, US-A-2857333, and NL-C-100963. However, it turns out that polyamines lead to insufficient inhibition of corrosion by water of metals, in the sense that the loss of thickness of the metallic surfaces which one wanted to protect is of the order of 80 to 150 μm. / year under the best conditions of employment. It also happens that, if the polyamines used alone have an anticorrosive effect at high doses (that is to say at doses greater than or equal to 100 ppm), they accelerate corrosion at lower doses (of the order ten ppm in particular).

On sait également que l'on a proposé en tant que moyens anti-tartre des substances organiques polymères (désignées ci-après «B») qui sont notamment obtenues par polymérisation ou copolymérisation à partir d'un monomère présentant un motif

Figure imgb0001
(où Ro est un radical nitrile, amide, imide, acide carboxylique ou carboxylate). De telles substances anti-tartre ont été notamment préconisées dans FR-A-2178808, FR-A-2 379 616 et US-A-4 048 066.It is also known that polymeric organic substances have been proposed as anti-scaling means (hereinafter designated "B") which are in particular obtained by polymerization or copolymerization from a monomer having a unit
Figure imgb0001
 (where R o is a nitrile, amide, imide, carboxylic acid or carboxylate radical). Such anti-tartar substances have been recommended in particular in FR-A-2178808, FR-A-2 379 616 and US-A-4 048 066.

Il se trouve que les substances B, notamment celles préconisées dans le document FR-A-2 178 808 précité, ne peuvent pas être toutes utilisées en tant qu'agents inhibiteurs de corrosion comme cela ressort de l'article de R.H.C. ANDREW et al., Br. Corros. J. (Quarterly) 9 (N° 4), 238-243 (1974) qui enseigne que les polymères polyélectrolytes hydrosolubles connus comme agents anti-tartre peuvent accélérer la corrosion, et qui démontre que (i) deux polymères polyacry- liques hydrosolubles, l'un anionique, l'autre cationique, accélèrent la corrosion en milieu neutre ou alcalin, et (ii) seul le polymére anionique est moyennement anti-corrosif pour l'acier doux en milieu acide. En bref, un nombre restreint de substances anti-tartre B, notamment celles décrites dans l'article de R.H.D. ANDREW précité, dans l'article de M. KHULLAR et al., 5th European Symposium on Corrosion Inhibitors vol. 3, pages 815-825 (Université de Ferrare, Italie, 1980) et dans US-A-4048065, présente un effet inhibiteur de corrosion. Cet effet est modéré (il faut, selon M. KHULLAR et al., associer au moyen B - dans le cas d'espèce un lignosulfonate - un dérivé d'acide phosphonique et Zn2+ pour obtenir une bonne inhibition de la corrosion) et sa manifestation est fonction du choix du moyen B, de la composition de la surface métallique à protéger et de la nature des eaux devant venir au contact de ladite surface métallique.It turns out that substances B, in particular those recommended in the document FR-A-2 178 808 cited above, cannot all be used as corrosion-inhibiting agents as is apparent from the article by RHC ANDREW et al. , Br. Corros. J. (Quarterly) 9 (No. 4), 238-243 (1974) which teaches that water-soluble polyelectrolyte polymers known as anti-scale agents can accelerate corrosion, and which demonstrates that (i) two water-soluble polyacrylic polymers, one anionic, the other cationic, accelerate corrosion in neutral or alkaline medium, and (ii) only the anionic polymer is moderately anti-corrosive for mild steel in acidic medium. In short, a limited number of anti-tartar B substances, in particular those described in the article by RHD ANDREW cited above, in the article by M. KHULLAR et al., 5th European Symposium on Corrosion Inhibitors vol. 3, pages 815-825 (University of Ferrara, Italy, 1980) and in US-A-4048065, has a corrosion inhibiting effect. This effect is moderate (it is necessary, according to M. KHULLAR et al., To combine by means B - in the present case a lignosulfonate - a derivative of phosphonic acid and Zn 2 + to obtain a good inhibition of corrosion) and its manifestation is a function of the choice of means B, the composition of the metal surface to be protected and the nature of the water which has to come into contact with said metal surface.

On connaît enfin, de EP-A-10485, une autre solution pour résoudre le problème technique de l'inhibition de la corrosion par l'eau surfaces métalliques. Cette solution, qui est très efficace, consiste à utiliser, comme moyen inhibiteur, une composition insoluble dans l'eau renfermant en association au moins une polyamine ayant un poids moléculaire supérieur ou égal à 320, et au moins un dérivé d'acide alkylènephosphonique choisi parmi l'ensemble constitué par les dérivés d'acide aminoalkylènephosphonique et les dérivés d'acide alkylènepolyphosphonique. Or il se trouve que cette solution technique, qui conduit à des taux d'inhibition de corrosion élevés, ne convient pas dans les cas d'utilisation qui impliquent un rejet de l'eau du circuit dans des lacs ou rivières, du fait de la présence d'un ou plusieurs composés organo-phosphorés polluants.Finally, from EP-A-10485, another solution is known to solve the technical problem of inhibiting corrosion by water of metal surfaces. This solution, which is very effective, consists in using, as an inhibiting means, a composition insoluble in water containing in association at least one polyamine having a molecular weight greater than or equal to 320, and at least one derivative of alkylene phosphonic acid chosen among the group consisting of aminoalkylenephosphonic acid derivatives and alkylene polyphosphonic acid derivatives. However, it turns out that this technical solution, which leads to high corrosion inhibition rates, is not suitable in the cases of use which involve a rejection of the water of the circuit in lakes or rivers, because of the presence of one or more polluting organophosphorus compounds.

On sait par ailleurs que dans US-A-3654993 est envisagée une composition inhibitrice de corrosion, destinée à être introduite dans une formation souterraine d'où sont pompés des fluides hydrocarbonés et/ou aqueux, et qui comprend une diamine (à savoir une alkyl (en Cs_C3o)-amino- propylèneamine) et un polyélectrolyte du type acide polyacrylique, polyacrylate ou polyacrylamide (de préférence un polyacrylamide hydrolysé ayant 20 à 40% de groupes amide non hydrolysés). Selon les indications données aux exemples 1 et Il de ce document il est important que la diamine et le polyélectrolyte soient associés à d'autres ingrédients (milieu acide fort, un tensioactif, un amide, un alcool notamment l'isopropanol) pour que leur mélange soit efficace.We also know that in US-A-3654993 a corrosion inhibiting composition is envisaged, intended to be introduced into an underground formation from which hydrocarbon and / or aqueous fluids are pumped, and which comprises a diamine (namely an alkyl (in C s _C 3o ) -amino-propyleneamine) and a polyelectrolyte of the polyacrylic acid, polyacrylate or polyacrylamide type (preferably a hydrolyzed polyacrylamide with 20 to 40% of non-hydrolyzed amide groups). According to the indications given in Examples 1 and II of this document, it is important that the diamine and the polyelectrolyte are combined with other ingredients (strong acid medium, a surfactant, an amide, an alcohol, in particular isopropanol) so that their mixture be effective.

Pour résoudre le problème technique de l'inhibition de la corrosion des surfaces métalliques par l'eau, on propose, selon l'invention, une nouvelle solution qui fait appel, en tant que moyen inhibiteur de corrosion, à une association d'une polyamine A avec une substance polymère B différente de celles envisagées dans US-A-3654993 précité. On a en effet découvert de façon inattendue que l'association de A et B conduit à des résultats aussi intéressants que ceux obtenus selon l'enseignement de EP-A-10485 précité quelles que soient la composition de la surface métallique à protéger et la nature de l'eau en contact avec ladite surface, alors que l'utilisation des moyens A et B seuls était insuffisante.To solve the technical problem of inhibiting corrosion of metallic surfaces by water, a new solution is proposed according to the invention which uses, as a corrosion inhibiting means, a combination of a polyamine A with a polymeric substance B different from those envisaged in US-A-3654993 cited above. It has in fact been unexpectedly discovered that the association of A and B leads to results as interesting as those obtained according to the teaching of EP-A-10485 cited above whatever the composition of the metal surface to be protected and the nature water in contact with said surface, when the use of means A and B alone was insufficient.

Plus précisément, on préconise selon l'invention une nouvelle composition inhibitrice de corrosion pour les surfaces métalliques en contact avec de l'eau, comprenant au moins une polyamine et au moins une substance polymère obtenue à partir d'un monomère présentant un motif C = C, ladite composition étant caractérisée en ce qu'elle renferme en association

  • a) une substance choisie parmi les polyamines ayant un poids moléculaire supérieur ou égal à 228 et répondant à la formule générale
    Figure imgb0002
    (où R représente un radical hydrocarboné aliphatique saturé ou insaturé en C12-C22, m représente un nombre entier compris entre 2 et 8 inclus et n représente un nombre entier compris entre 1 et 7 inclus, R, m et n étant tels que le poids moléculaire desdites polyamines soit supérieur ou égal à 228) et leurs mélanges; et
  • b) une substance polyélectrolyte polymère choisie parmi:
    • (i) les dérivés du type polymaléique répondant à la formule générale
      Figure imgb0003
      (où R3 et R4, qui peuvent être identiques ou différents, représentent chacun l'atome d'hydrogène ou un groupe alkyle en Cl-C4, et R1 est H, alkyle en C1-C4, Na+, K+ ou NH4 +, et n1 est un nombre entier supérieur ou égal à 2);
    • (ii) les dérivés copolymères du type styrène-maléique présentant un motif
      Figure imgb0004
      (où R1 est défini comme indiqué ci-dessus, n2 est un nombre entier supérieur ou égal à 1, et n3 et n4, identiques ou différents, sont des nombres entiers supérieurs ou égaux à 1, un seul des n3 et n4 pouvant, dans le cas d'un copolymère séquencé, représenter 0)
    • (iii) les dérivés du type polyéthylèneimine répondant à la formule générale
      Figure imgb0005
      [où R2 est H ou alkyle en C1-C4, n1 est défini comme indiqué ci-dessus, X- représente un ion halogénure F-, CI-, Br- ou I- (et de préférence CI-)];
    • (iv) les dérivés du type polyvinylammonium répondant à la formule générale
      Figure imgb0006
      (où R2, n1 et X- sont définis comme indiqué ci-dessus);
    • (v) les dérivés copolymères du type acrylique-styrène-sulfonique présentant un motif
      Figure imgb0007
      (où R1, R2, n2, n3 et n4 sont définis comme indiqué ci-dessus);
    • (vi) les dérivés du type lignosulfonate répondant à la formule générale
      Figure imgb0008
      (où R1 et n1 sont définis comme indiqués ci-dessus); et,
    • (vii) leurs mélanges.
More specifically, according to the invention, a new corrosion-inhibiting composition is recommended for metallic surfaces in contact with water, comprising at least one polyamine and at least one polymeric substance obtained from a monomer having a unit C = C, said composition being characterized in that it contains in combination
  • a) a substance chosen from polyamines having a molecular weight greater than or equal to 228 and corresponding to the general formula
    Figure imgb0002
     (where R represents a saturated or unsaturated C 12 -C 22 aliphatic hydrocarbon radical, m represents an integer between 2 and 8 inclusive and n represents an integer between 1 and 7 inclusive, R, m and n being such that the molecular weight of said polyamines is greater than or equal to 228) and their mixtures; and
  • b) a polymeric polyelectrolyte substance chosen from:
    • (i) derivatives of the polymaleic type corresponding to the general formula
      Figure imgb0003
       (where R 3 and R 4 , which may be the same or different, each represents a hydrogen atom or a C 1 -C 4 alkyl group, and R 1 is H, C 1 -C 4 alkyl, Na + , K + or NH 4 + , and n 1 is an integer greater than or equal to 2);
    • (ii) copolymer derivatives of the styrene-maleic type having a motif
      Figure imgb0004
       (where R 1 is defined as indicated above, n 2 is an integer greater than or equal to 1, and n 3 and n 4 , identical or different, are whole numbers greater than or equal to 1, only one of the n 3 and n 4 which can, in the case of a block copolymer, represent 0)
    • (iii) derivatives of the polyethyleneimine type corresponding to the general formula
      Figure imgb0005
       [where R 2 is H or C 1 -C 4 alkyl, n 1 is defined as indicated above, X- represents a halide ion F-, CI-, Br- or I- (and preferably CI-)] ;
    • (iv) derivatives of the polyvinylammonium type corresponding to the general formula
      Figure imgb0006
       (where R 2 , n 1 and X- are defined as indicated above);
    • (v) copolymer derivatives of the acrylic-styrene-sulfonic type having a motif
      Figure imgb0007
       (where R 1 , R 2 , n 2 , n 3 and n 4 are defined as indicated above);
    • (vi) derivatives of the lignosulfonate type corresponding to the general formula
      Figure imgb0008
       (where R 1 and n 1 are defined as indicated above); and,
    • (vii) their mixtures.

Parmi les polyamines de formule I qui conviennent, on peut notamment mentionner les do- décyltri (aminopropylène)amine, dodécylté- tra (aminopropylène)amine, hexadécyltri(amino- propylène)amine, hexadécényltétra(aminopropy- lène)amine, octadécyl(aminopropylène)amine, octadécylpenta(aminopropylène)amine, octadé- cényltétra(aminopropylène)amine, octadécyl- tri(aminopropylène)amine, octadécényl- hexa(aminopropylène)amine, hexadécylhep- ta(aminopropylène)amine, dodécyldi(aminoéthy- lène)amine, octadécyl(aminobutylène)amine et octadécényl(aminopropylène)amine.Among the polyamines of formula I which are suitable, mention may in particular be made of decidyltri (aminopropylene) amine, dodecyltetra (aminopropylene) amine, hexadecyltri (aminopropylene) amine, hexadecenyltetra (aminopropylene) amine, octadecyl (aminopropylene) amine, octadecylpenta (aminopropylene) amine, octadecenyltetra (aminopropylene) amine, octadecyl- tri (aminopropylene) amine, octadecenyl-hexa (aminopropylene) amine, hexadecylhepta (aminopropylene) amine, dodecyldy (aminoethyecene) aminobutylene) amine and octadecenyl (aminopropylene) amine.

Les amines de formule I peuvent être utilisées telles qu'on peut les obtenir dans le commerce, seules ou mélangées entre elles, sous leurs formes pures, ou techniques. On peut également utiliser des polyamines préparées à partir d'acides gras d'origine animale, végétale ou de synthèse. Parmi les polyamines commercialisées qui conviennent, on peut notamment citer les produits connus sous les noms de marque DUO-MEEN, DINORAM, TRINORAM, POLYRAM, LILA-MIN, et CEMULCAT qui renferment au moins une polyamine I ayant un poids moléculaire supérieur ou égal à 228. Parmi ces derniers produits on peut mentionner le «DINORAM 0» qui renferme approximativement 75% en poids sec d'oléylami- no-propylèneamine, 9% en poids sec de stéarylaminopropylèneamine et 6% en poids sec d'hexa- décylaminopropylèneamine, le «DINORAM S» qui renferme approximativement 43% en poids sec de stéarylaminopropylèneamine, 28% en poids sec d'oléylaminopropylèneamine et 28% en poids sec d'hexadécylaminopropylèneamine, ces produits étant commercialisés par la Société CECA.The amines of formula I can be used as they can be obtained commercially, alone or mixed together, in their pure or technical forms. One can also use polyamines prepared from fatty acids of animal, vegetable or synthetic origin. Among the polyamines sold which are suitable, mention may be made in particular of the products known under the brand names DUO-MEEN, DINORAM, TRINORAM, POLYRAM, LILA-MIN, and CEMULCAT which contain at least one polyamine I having a molecular weight greater than or equal to 228. Among these latter products, mention may be made of “DINORAM 0” which contains approximately 75% by dry weight of oleylamino-propyleneamine, 9% by dry weight of stearylamopropyleneamine and 6% by dry weight of hexadecylaminopropyleneamine “DINORAM S” which contains approximately 43% by dry weight of stearylaminopropyleneamine, 28% by dry weight of oleylaminopropyleneamine and 28% by dry weight of hexadecylaminopropyleneamine, these products being marketed by CECA.

Les polyélectrolytes organiques polymériques ont un poids moléculaire supérieur ou égal à environ 150 et de préférence un poids moléculaire supérieur ou égal à 300. Le poids moléculaire supérieur peut être élevé, et peut être de l'ordre de 2 000 000 ou plus.The polymeric organic polyelectrolytes have a molecular weight greater than or equal to about 150 and preferably a molecular weight greater than or equal to 300. The higher molecular weight can be high, and can be of the order of 2,000,000 or more.

De façon avantageuse, on pourra faire appel à des polyélectrolytes de formule Il ayant un poids moléculaire compris entre 800 et 1000 (notamment à des acides polymaléiques commercialisés sous le nom de marque de BELCLENE par la Société CIBA-GEIGY), à des polyélectrolytes de formule IV ayant un poids moléculaire élevé de l'ordre de 5 x 105 environ à 106 environ (notamment à des polyéthylèneimines commercialisées sous le nom de marque de SEDIPUR par la Société BASF), à des polyélectrolytes de formule V ayant un poids moléculaire élevé de l'ordre de 5 x 105 environ à 106 environ (notamment à des produits du type polyvinylammonium commercialisés sous le nom de marque de PRIMAFLOC par la Société ROHM & HAAS), à des polyélectrolytes de formule VI ayant un poids moléculaire moyen de l'odre de 104 environ à 105 environ (notamment à des copolymères acide acrylique- acide styrènesulfonique et à leurs sels avec des métaux alcalins tels que Na et K, commercialisés sous le nom de marque de SLUDGTROL par la Société DEARBORN), et à des polyélectrolytes de formule VII ayant un poids moléculaire compris entre 103 et 105 (notamment à des lignosulfo- nates de sodium commercialisés sous le nom de marque de WANIN par la Société IVAKEM).Advantageously, use may be made of polyelectrolytes of formula II having a molecular weight of between 800 and 1000 (in particular polymaleic acids marketed under the brand name of BELCLENE by the company CIBA-GEIGY), polyelectrolytes of formula IV having a high molecular weight of the order of approximately 5 × 10 5 to approximately 10 6 (in particular to polyethyleneimines sold under the brand name of SEDIPUR by the company BASF), to polyelectrolytes of formula V having a high molecular weight of the order of approximately 5 × 10 5 to approximately 10 6 (in particular to products of the polyvinylammonium type marketed under the brand name of PRIMAFLOC by the company ROHM & HAAS), to polyelectrolytes of formula VI having an average molecular weight of the order from about 10 4 to about 10 5 (in particular to acrylic acid-styrenesulfonic acid copolymers and to their salts with alkali metals such as Na and K, sold under the brand name of SL UDGTROL by the company DEARBORN), and to polyelectrolytes of formula VII having a molecular weight of between 10 3 and 10 5 (in particular to sodium lignosulfonates marketed under the brand name of WANIN by the company IVAKEM).

Parmi les polyélecrtolytes préférés mentionnés ci-dessus, les substances les plus intéressantes selon l'invention sont les produits de formule II.Among the preferred polyelecrtolytes mentioned above, the most advantageous substances according to the invention are the products of formula II.

Les polyélectrolytes répondant aux formules Il à VII ci-dessus peuvent être des produits chimiquement purs, ou des produits techniques nor- malementfabriqués par l'industrie et commercialisés sous forme liquide ou pâteuse, ou encore sous forme de solutions aqueuses à toutes concentrations, sans que le choix de l'une de ces formes de présentation puisse constituer une quelconque limitation à la présente invention. On préférera cependant, d'une manière générale, pour des raisons commerciales et par commodité, les polyélectrolytes mis dans le commerce sous forme de solutions aqueuses.The polyelectrolytes corresponding to formulas II to VII above may be chemically pure products, or technical products normally manufactured by industry and marketed in liquid or pasty form, or also in the form of aqueous solutions at all concentrations, without the choice of one of these forms of presentation may constitute any limitation to the present invention. However, we generally prefer for commercial reasons and for convenience. polyelectrolytes commercially available in the form of aqueous solutions.

De façon avantageuse, la composition selon l'invention renfermera (a) 1 à 8 parties en poids sec de polyamine et b) 2 à 9 parties en poids sec de polyélectrolyte, le rapport pondéral a/b étant alors compris entre 1 : 9 et 4:1.Advantageously, the composition according to the invention will contain (a) 1 to 8 parts by dry weight of polyamine and b) 2 to 9 parts by dry weight of polyelectrolyte, the weight ratio a / b then being between 1: 9 and 4: 1.

Le procédé de préparation de la composition inhibitrice de corrosion est mis en oeuvre selon une méthode connue en soi qui consiste à mélanger une ou plusieurs polyamines avec un ou plusieurs polyelectrolytes. Selon le meilleur mode que l'on préconise, on fait appel à un procédé qui est caractérisé en ce que l'on amène à l'état liquide, par chauffage suffisant, la ou les polyamines choisies qu'on introduit progressivement, sous agitation modérée, ou vive, selon le cas, dans une solution aqueuse du ou des polyélectrolytes choisis et préalablement chauffés à une température inférieure à celle de la polyamine.The process for preparing the corrosion inhibiting composition is carried out according to a method known per se which consists in mixing one or more polyamines with one or more polyelectrolytes. According to the best mode that is recommended, use is made of a process which is characterized in that the selected polyamine or polyamines are introduced into the liquid state, by sufficient heating, which are gradually introduced, with moderate stirring. , or bright, as the case may be, in an aqueous solution of the polyelectrolyte (s) chosen and previously heated to a temperature lower than that of the polyamine.

Selon la nature des moyens a et b qui sont utilisés, la composition qui est obtenue peut se présenter sous forme de gel, ou de pâte, ou de cire. D'une manière générale, la composition selon l'invention est insoluble ou peu soluble dans l'eau, la solubilité dans l'eau étant nettement inférieure à 10 g/I.Depending on the nature of the means a and b which are used, the composition which is obtained may be in the form of a gel, or a paste, or a wax. In general, the composition according to the invention is insoluble or sparingly soluble in water, the solubility in water being much less than 10 g / l.

En pratique, la ou les polyamines seront fondues à une température comprise entre environ 30 et environ 85°C et versées dans le ou les polyélectrolytes amenés à une température comprise entre environ 15 et environ 60°C.In practice, the polyamine (s) will be melted at a temperature between approximately 30 and approximately 85 ° C. and poured into the polyelectrolyte (s) brought to a temperature between approximately 15 and approximately 60 ° C.

On comprend aisément que, lorsque les surfaces métalliques à protéger sont à basses températures, plus précisément à des températures inférieures à 60°C, telles les surfaces métalliques des humidificateurs d'air, des condenseurs, des réseaux d'eau glacée, on préférera choisir ceux, parmi les polyélectrolytes répondant aux formules Il à VII ci-dessus, et celles, parmi les polyamines aliphatiques répondant à la formule générale 1 ci-dessus, qui donnent, en mélange, des compositions possédant des points de ramollissement aussi bas que possible. De même que des mélanges à points de ramollissement plus élevés seront préférés comme inhibiteurs de corrosion vis-à-vis de surfaces métalliques soumises à des températures élevées, telles que par exemple celles constituant les tubes de chaudières à vapeur, ou de surchauffeurs, ou bien celles constituant les circuits de refroidissement des fours des industries métallurgiques et sidérurgiques.It is easily understood that, when the metal surfaces to be protected are at low temperatures, more precisely at temperatures below 60 ° C., such as the metal surfaces of air humidifiers, condensers, chilled water networks, it will be preferable to choose those, among the polyelectrolytes corresponding to the formulas II to VII above, and those, among the aliphatic polyamines corresponding to the general formula 1 above, which give, in mixture, compositions having softening points as low as possible. Similarly, mixtures with higher softening points will be preferred as corrosion inhibitors with respect to metal surfaces subjected to high temperatures, such as for example those constituting the tubes of steam boilers, or superheaters, or else those constituting the cooling circuits of the ovens of the metallurgical and steel industries.

Pour des raisons d'ordre pratique et, en particulier, du fait que la plupart des polyélectrolytes ne sont disponibles dans le commerce que sous forme de solutions aqueuses plus ou moins concentrées, il n'est pas économiquement recommandable d'éliminer l'eau de la composition selon l'invention, puisqu'elle est précisément destinée notamment à être redispersée dans l'eau pour son utilisation comme inhibiteur de corrosion. De plus, cette eau n'entrant en réaction avec aucun des constituants de la composition selon l'invention, et n'intervenant évidemment pas dans des propriétés inhibitrices de corrosion, ne sert que de milieu de dispersion de ladite composition selon l'aspect commercial qu'on désire lui conférer. Aussi, les quantités très variables d'eau que peut contenir ladite composition ne sauraient constituer une quelconque limitation à la présente invention.For practical reasons and, in particular, because most polyelectrolytes are only commercially available in the form of more or less concentrated aqueous solutions, it is not economically advisable to remove the water from the composition according to the invention, since it is specifically intended in particular to be redispersed in water for its use as a corrosion inhibitor. In addition, this water does not react with any of the constituents of the composition according to the invention, and obviously does not intervene in corrosion inhibiting properties, only serves as a medium for dispersing said composition according to the commercial aspect. that we want to give it. Also, the very variable amounts of water which said composition may contain cannot constitute any limitation to the present invention.

Les compositions pâteuses, ou gélifiées, réalisées selon l'invention, peuvent être introduites à l'aide d'une pompe volumétrique à piston, comme il s'en trouve dans le commerce, soit telles quelles dans l'eau des circuits industriels ou immobiliers à protéger, soit encore préalablement émulsionnées, ou dispersées dans une plus grande quantité d'eau à l'aide d'une ou de plusieurs substances tensio-actives du commerce et connues de l'homme de l'art comme capables de disperser les polyamines grasses. Les quantités de substances à propriétés tensio-actives utilisées à cet effet sont fonction de l'aspect commercial que l'on désire donner à de telles dispersions et ne sauraient constituer une quelconque limitation à la présente invention.The pasty or gelled compositions produced according to the invention can be introduced using a positive displacement piston pump, as is commercially available, either as is in the water of industrial or real estate circuits. to be protected, either still previously emulsified, or dispersed in a larger amount of water using one or more surface-active substances of commerce and known to those skilled in the art as capable of dispersing polyamines oily. The amounts of substances with surface-active properties used for this purpose depend on the commercial aspect which it is desired to give to such dispersions and should not constitute any limitation to the present invention.

A côté de l'application préférée selon l'invention décrite ci-dessus, il y a une autre application anti-corrosive selon laquelle on traite notamment par immersion les pièces métalliques que l'on veut protéger au moyen d'une composition inhibitrice selon l'invention, cette composition inhibitrice pouvant être, le cas échéant, sous forme de bain aqueux.Besides the preferred application according to the invention described above, there is another anti-corrosion application according to which the metal parts which one wishes to protect are treated in particular by immersion by means of an inhibiting composition according to the invention. the invention, this inhibiting composition possibly being, in the form of an aqueous bath.

D'autres avantages et caractéristiques selon l'invention seront mieux compris à la lecture qui va suivre d'exemples de préparation non limitatifs et d'essais justifiant le pouvoir inhibiteur de corrosion.Other advantages and characteristics according to the invention will be better understood on reading which will follow from nonlimiting examples of preparation and tests justifying the corrosion inhibiting power.

Dans le tableau 1 ci-après on a consigné un certain nombre d'exemples de compositions inhibitrices selon l'invention. Ces compositions peuvent être préparées selon les modalités opératoires suivantes.

Figure imgb0009
Figure imgb0010
 In Table 1 below, a certain number of examples of inhibitor compositions according to the invention are recorded. These compositions can be prepared according to the following operating methods.
Figure imgb0009
Figure imgb0010

Préparation (Exemple 1)Preparation (Example 1)

Dans un bécher en verre, en acier inoxydable ou en polyéthylène de 1 litre de capacité, on introduit à la température ambiante de 25°C 600 grammes d'une solution aqueuse à 500 g/I d'acide polymaléique répondant à la formule Il ci-dessus, et on introduit un agitateur en acier inoxydable capable de mettre en turbulence rapide la solution acide. On amène par ailleurs à la liquéfaction, par chauffage lent à 70°C environ, 130 grammes d'octadécylaminobutylèneamine que l'on ajoute rapidement à cette température à la solution acide maintenue sous vive agitation et qui est à 15°C. Lorsque toute la polyamine a été introduite, on diminue progressivement la vitesse d'agitation. La pâte obtenue après retour à la température ambiante apparaît, à l'étude plus approfondie, comme une dispersion inverse d'eau dans une phase organique, de couleur jaune ambré et qui s'avère pratiquement insoluble dans l'eau.In a glass, stainless steel or polyethylene beaker of 1 liter capacity, 600 grams of an aqueous solution containing 500 g / l of polymaleic acid corresponding to formula II are introduced at room temperature of 25 ° C. above, and a stainless steel agitator is introduced capable of rapidly turbulating the acid solution. Is also brought to liquefaction, by slow heating to about 70 ° C, 130 grams of octadecylaminobutyleneamine which is quickly added at this temperature to the acid solution maintained under vigorous stirring and which is at 15 ° C. When all the polyamine has been introduced, the stirring speed is gradually reduced. The paste obtained after returning to room temperature appears, upon further study, as a reverse dispersion of water in an organic phase, of amber yellow color and which turns out to be practically insoluble in water.

Cette composition constitue un excellent inhibiteur de corrosion comme les expérimentations exposées plus loin le démontrent.This composition constitutes an excellent corrosion inhibitor, as the experiments set out below demonstrate.

On a résumé ci-après les résultats des essais qui ont été entrepris, avec les compositions objet de l'invention, selon deux méthodes différentes.The results of the tests which have been undertaken with the compositions which are the subject of the invention are summarized below according to two different methods.

Méthode AMethod A

Méthode de mesure indirecte de la corrosion par analyse quantitative des produits de corrosion, après dissolution, par spectrométrie d'absorption atomique.Method for indirect measurement of corrosion by quantitative analysis of corrosion products, after dissolution, by atomic absorption spectrometry.

a) Matériel et protocolea) Material and protocol

L'éprouvette destinée aux essais se présente sous la forme d'un cylindre de 1 cm2 de section, vissé sur un axe de rotation, l'ensemble étant revêtu d'une gaine thermorétractable étanche. Elle est en acier (nuance XC 35).The test piece is in the form of a cylinder with a cross-section of 1 cm 2 , screwed onto an axis of rotation, the assembly being coated with a tight heat-shrinkable sheath. It is made of steel (grade XC 35).

La surface de chaque éprouvette est polie au papier abrasif (au carbure de silicium de grade 80), rincée à l'eau puis nettoyée et dégraissée dans l'alcool sous ultra-sons et finalement séchée à l'air chaud pulsé.The surface of each specimen is polished with abrasive paper (with silicon carbide of grade 80), rinsed with water then cleaned and degreased in alcohol under ultrasound and finally dried with hot pulsed air.

La cellule d'essai est constituée d'un récipient de 300 ml en verre «PYREX» muni d'un orifice pour introduction de l'éprouvette tournante.The test cell consists of a 300 ml "PYREX" glass container provided with an opening for the introduction of the rotating test piece.

L'éprouvette tournante est introduite dans le milieu agressif et reste au contact dudit milieu pendant 24 heures. Sa vitesse de rotation est de 1000 tours/minute.The rotating specimen is introduced into the aggressive medium and remains in contact with said medium for 24 hours. Its rotation speed is 1000 revolutions / minute.

Le milieu agressif est constitué par l'eau adoucie du Tableau III ci-après. La quantité utilisée est de 250 ml.The aggressive medium consists of the softened water of Table III below. The amount used is 250 ml.

Après 24 heures, on décape par ultrasons les produits de corrosion adhérents à l'éprouvette pour les faire passer dans le milieu agressif. On recueille le milieu aqueux résultant et pour avoir une solution homogène, les produits de corrosion sont solubilisés par acidification avec HCI.After 24 hours, the corrosion products adhering to the test piece are ultrasonically scoured to pass them through the aggressive medium. The resulting aqueous medium is collected and to have a homogeneous solution, the corrosion products are dissolved by acidification with HCl.

La teneur des divers cations présents à l'état de traces dans la solution résultante est déterminée par spectrométrie d'absorption atomique. La teneur en fer dans le cas d'une éprouvette en acier (nuance XC 35) est directement proportionnelle à l'intensité de l'effet corrosif. Dans le cas d'espèce la présence de fer dissous dans la solution se traduit sur l'appareillage par l'apparition d'un pic de hauteur croissante avec la teneur en fer.The content of the various cations present in trace amounts in the resulting solution is determined by atomic absorption spectrometry. The iron content in the case of a steel test piece (grade XC 35) is directly proportional to the intensity of the corrosive effect. In the present case, the presence of dissolved iron in the solution results in the apparatus by the appearance of a peak of increasing height with the iron content.

Le rapport des hauteurs de pic (exprimées en cm) avec et sans inhibiteur permet de déduire l'efficacité inhibitrice E (%) selon la relation

Figure imgb0011
(où h et h° représentent respectivement les hauteurs des pics avec et sans inhibiteurs).The ratio of peak heights (expressed in cm) with and without inhibitor makes it possible to deduce the inhibitory efficiency E (%) according to the relationship
Figure imgb0011
 (where h and h ° respectively represent the heights of the peaks with and without inhibitors).

b) Résultatsb) Results

Les résultats consignés dans le Tableau Il ci-après montrent que le pourcentage d'inhibition (E%) est supérieur ou égal à 80,5% pour les compositions selon l'invention.

Figure imgb0012
The results recorded in Table II below after show that the percentage of inhibition (E%) is greater than or equal to 80.5% for the compositions according to the invention.
Figure imgb0012

Méthode BMethod B

Mesure directe de la corrosion par détermination de la perte de poids d'éprouvettes.Direct measurement of corrosion by determining the weight loss of test pieces.

a) Matériel et protocolea) Material and protocol

Le matériel et le potocole relatifs à la détermination de la perte de poids des éprouvettes par une mesure directe du type gravimétrique, sont ceux décrits dans le document EP-A-10 485 précité.The equipment and the potocole relating to the determination of the weight loss of the test pieces by a direct measurement of the gravimetric type, are those described in the aforementioned document EP-A-10,485.

Les essais ont été entrepris sur des éprouvettes en acier, en cuivre et en aluminium avec une eau brute (eau de ville) et une eau adoucie (très corrosive du fait de la présence d'oxygène dissous) obtenue par passage de ladite eau brute sur une résine échangeuse d'ion, ces eaux ayant les caractéristiques données dans le Tableau III ci-après.

Figure imgb0013
The tests were undertaken on steel, copper and aluminum specimens with raw water (tap water) and softened water (very corrosive due to the presence of dissolved oxygen) obtained by passing said raw water over an ion exchange resin, these waters having the characteristics given in Table III below.
Figure imgb0013

La mesure de la perte de poids a été effectuée dans des essais de corrosion du type «chauffage» et du type «refroidissement». Pour simplifier la lecture des résultats, cette perte de poids a été traduite en vitesse de corrosion selon la relation

Figure imgb0014
dans laquelle

  • P = perte de poids exprimée en milligrammes;
  • J = nombre de jours d'exposition au milieu agressif;
  • S = surface externe de l'éprouvette exprimée en cm2;
  • d = masse spécifique du métal de l'éprouvette en g/cm3.
The measurement of the weight loss was carried out in corrosion tests of the “heating” type and of the “cooling” type. To simplify the reading of the results, this weight loss has been translated into corrosion rate according to the relationship
Figure imgb0014
 in which
  • P = weight loss expressed in milligrams;
  • D = number of days of exposure to the aggressive medium;
  • S = external surface of the test piece expressed in c m2;
  • d = specific mass of the metal of the test piece in g / c m3 .

A la différence de la demande européenne précitée qui donnait le pourcentage de corrosion, les résultats des Tableaux IV et V qui suivent font état de l'efficacité inhibitrice (pourcentage d'inhibition) qui est définie par la relation

Figure imgb0015
(où v et v° représentent respectivement les vitesses de corrosion exprimées en µm/an avec et sans inhibiteurs).Unlike the above-mentioned European application which gave the percentage of corrosion, the results of Tables IV and V which follow show the inhibitory efficacy (percentage of inhibition) which is defined by the relation
Figure imgb0015
 (where v and v ° respectively represent the corrosion rates expressed in µm / year with and without inhibitors).

b) Résultatsb) Results

Les résultats des essais de corrosion du type «chauffage» ont été consignés dans le Tableau IV et ceux du type «refroidissement» dans le Tableau V ci-après.

Figure imgb0016
Figure imgb0017
Figure imgb0018
 The results of the corrosion tests of the “heating” type were reported in Table IV and those of the “cooling” type in Table V below.
Figure imgb0016
Figure imgb0017
Figure imgb0018

Par ailleurs, l'examen au microscope montre que toutes les éprouvettes et la sonde chauffée en acier sont parfaitement exemptes de piqûres avec les compositions selon l'invention. Les éprouvettes en acier sont lisses, de couleur légèrement brune, plus prononcée sur la sonde chauffée. Les éprouvettes en cuivre et en aluminium sont un peu moins brillantes dans les essais du type «refroidissment» que dans les essais du type «chauffage». Les autres éléments métalliques du circuit apparaissent après démontage, brossage et rinçage à l'acide sulfamique parfaitement exempts de dépôts de corrosion et sans aucune attaque visible.Furthermore, examination under the microscope shows that all the test pieces and the heated steel probe are perfectly free from pitting with the compositions according to the invention. The steel samples are smooth, slightly brown in color, more pronounced on the heated probe. The copper and aluminum specimens are slightly less shiny in the "cooling" type tests than in the "heating" type tests. The other metallic elements of the circuit appear after disassembly, brushing and rinsing with sulfamic acid perfectly free of corrosion deposits and without any visible attack.

Les résultats des Tableaux IV et V démontrent les propriétés inhibitrices remarquables des compositions selon l'invention, puisque aucune corrosion n'a pu être supérieure à 55 µm/an pour l'acier, à 10 um/an pour le cuivre et à 18 µm/an pour l'aluminium.The results of Tables IV and V demonstrate the remarkable inhibitory properties of the compositions according to the invention, since no corrosion could have been greater than 55 μm / year for the steel, 10 μm / year for the copper and 18 μm / year for aluminum.

Il résulte enfin de l'ensemble des Tableaux II, IV et V que les compositions selon l'invention sont des inhibiteurs de corrosion efficaces, qu'elles peuvent être utilisées pour toute surface métallique quelle que soit l'eau (eau brute, eau adoucie, eau salée), et que leur pouvoir inhibiteur est supérieur à celui de leurs constituants utilisés seuls.It finally follows from all of Tables II, IV and V that the compositions according to the invention are effective corrosion inhibitors, that they can be used for any metallic surface whatever the water (raw water, softened water , salt water), and that their inhibitory power is greater than that of their constituents used alone.

Claims (12)

1. A corrosion inhibiting composition for metallic surfaces in contact with water, containing at least one polyamine component and at least one polyelectrolyte component, said composition being characterized in that it comprises in association
a) a substance selected from the polyamines having a molecular weight higher than or equal to 228 and corresponding to the general formula
Figure imgb0032
(in which R represents a saturated or unsaturated C12-C22 hydrocarbon aliphatic radical, m is an integer of between 2 and 8 inclusive, and n is an integer of between 1 and 7 inclusive, the R, m and n values being such that the molecular weight of said polyamines is higher than or equal to 228) and mixtures thereof; and
b) a polymeric organic polyelectrolyte selected from
(i) the derivatives of the polymaleic type corresponding to the general formula
Figure imgb0033
(wherein R3 and R4, which may be identical or different, each represent a hydrogen atom or a C1-C4 alkyl group, R1 is H, C1-C4 alkyl, Na+, K+ or NH4 +, and n is an integer higher than or equal to 2);
(ii) the derivatives of the styrene-maleic type having an unit
Figure imgb0034
(wherein R1 is defined as indicated above, n2 is an integer higher than or equal to 1, and n3 and n4, which may be identical or different, each represent an integer higher than or equal to 1, one of the n3 and n4 being able, in the case of a sequenced copolymer, to represent 0);
(iii) the derivatives of the polyethyleneimine type corresponding to the general formula:
Figure imgb0035
(wherein R2 is H or C1-C4 alkyl, n1 is defined as indicated above,X- represents a F-, Cl-, Br- or I- halogenide ion);
(iv) the derivatives of the polyvinylammonium type of the general formula
Figure imgb0036
(wherein R2, n1 and X- are defined as indicated above);
(v) the copolymer derivatives of the acrylic-styrenesulfonic type having an unit
Figure imgb0037
(wherein R1, R2, n2, n3 and n4 are defined as indicated above);
(vi) the derivatives of the lignosulfonate type corresponding to the general formula
Figure imgb0038
(wherein R1 and n1 are defined as indicated above); and
(vii) mixtures thereof.
2. A corrosion inhibiting composition according to claim 1, characterized in that, the polyelectrolyte component is selected from the derivatives of the polymaleic type of the general formula
Figure imgb0039
(wherein R3 and R4, which may be identical or different each represent a hydrogen atom or a C1-C4 alkyl group, R1 is H, C1-C4 alkyl, Na+, K+, or NH4 +, and n1 is an integer higher than or equal to 2); and mixtures thereof.
3. A corrosion inhibiting composition according to claim 1, characterized in that the polyelectrolyte component is selected from the copolymer derivatives of the styrene-maleic type having an unit
Figure imgb0040
(wherein R1 is defined as indicated above, n2 is an integer higher than or equal to 1, and n3 and n4, which may be identical or different, each represent an integer higher than or equal to 1, one of the n3 and n4 being able, in the case of a sequenced copolymer, to represent 0), and mixtures thereof.
4. A corrosion inhibiting composition according to claim 1, characterized in that the polyelectrolyte component is selected from the derivatives of the polyethyleneimine type corresponding to the general formula
Figure imgb0041
(wherein R2 is H or C1-C4 alkyl, n1 is defined as indicated above, X- represents a F-, Cl-, Br- or I- halogenide ion); and mixtures thereof.
5. A corrosion inhibiting composition according to claim 1, characterized in that the polyelectrolyte component is selected from the derivatives of the polyvinylammonium type of the general formula:
Figure imgb0042
(wherein R2, n1 and X- are defined as indicated above); and mixtures thereof.
6. A corrosion inhibiting composition according to claim 1, characterized in that the polyelectrolyte component is selected from the copolymer derivatives of the acrylic-styrenesulfonic type having an unit
Figure imgb0043
(wherein R1, R2, n2, n3 and n4 are defined as indicated above); and mixtures thereof.
7. A corrosion inhibiting composition according to claim 1, characterized in that the polylelec- trolyte component is selected from the derivatives of the lignosulfonate type corresponding to the general formula
Figure imgb0044
(wherein R1 and n1 are defined as indicated above); and mixtures thereof.
8. A corrosion inhibiting composition according to claim 1, characterized in that it comprises
(a) from 1 to 8 parts by dry weight of polyamine 1, and
(b) from 2 to 9 parts by dry weight of polyelectrolyte,

the a/b weight ratio being comprised between 1:9and4:1.
9. A corrosion inhibiting composition according to any one of claims 1-8, characterized in that it is presented in the form of an aqueous suspension or dispersion containing a surfactant means.
10. A method for preparing a corrosion inhibiting composition according to claim 1, characterized in that the polyamine I is introduced into an aqueous solution of the polymeric organic polyelectrolyte, said polyelectrolyte in aqueous solution being at a temperature lower than that of the polyamine I.
11. A use of a composition according to any one of claims 1-9 for inhibiting corrosion of a metallic surface, characterized in that said metallic surface is treated with an aqueous suspension or dispersion comprising a corrosion inhibiting composition according to any one of claims 1-9.
12. A use according to claim 11, for inhibiting corrosion of water circuits, characterized in that the aqueous suspension or dispersion comprising a corrosion inhibiting composition according to any one of claims 1-9 is introduced into the water circuits.
EP81400861A 1981-05-27 1981-05-27 Corrosion inhibiting composition, process for its preparation and its use in the field of metal surface protection Expired EP0065609B1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
AT81400861T ATE15817T1 (en) 1981-05-27 1981-05-27 ANTI-CORROSION COMPOSITION, PROCESS FOR THEIR PRODUCTION AND ITS APPLICATION IN THE FIELD OF METAL SURFACE PROTECTION.
EP81400861A EP0065609B1 (en) 1981-05-27 1981-05-27 Corrosion inhibiting composition, process for its preparation and its use in the field of metal surface protection
DE8181400861T DE3172413D1 (en) 1981-05-27 1981-05-27 Corrosion inhibiting composition, process for its preparation and its use in the field of metal surface protection

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP81400861A EP0065609B1 (en) 1981-05-27 1981-05-27 Corrosion inhibiting composition, process for its preparation and its use in the field of metal surface protection

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EP0065609B1 true EP0065609B1 (en) 1985-09-25

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FR2723750B1 (en) * 1994-08-04 1996-10-25 Concorde Chimie France SCALING AND CORROSION INHIBITOR COMPOSITION FOR PROTECTING SURFACES IN CONTACT WITH WATER AND PROCESS FOR PREPARING THE SAME.
ATE144968T1 (en) † 1994-08-22 1996-11-15 Faborga Sa AGENT FOR PREVENTING EXCEPTIONS AND OXYGEN CORROSION IN PROCESS WATERS
FR2846670B1 (en) * 2002-11-06 2005-09-23 Concorde Chimie INHIBITOR COMPOSITION FOR ENCOURAGING AND CORROSION OF WATER CIRCUITS
EP2048203A1 (en) * 2007-10-12 2009-04-15 Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V. Corrosion inhibiting coating for active corrosion protection of metal surfaces comprising a sandwich-like inhibitor complex
FR2926302B1 (en) * 2008-01-14 2014-03-07 Eads Europ Aeronautic Defence NANOSTRUCTURE ANTI-CORROSION COATING, STRUCTURE COMPRISING SAME, METHOD FOR ANTI-CORROSION PROTECTION OF A SUBSTRATE.
US8613847B2 (en) 2008-11-19 2013-12-24 King Fahd University Of Petroleum And Minerals Method of applying polyelectrolyte multilayer film for corrosion control
WO2016130817A1 (en) 2015-02-11 2016-08-18 Cytec Industries Inc. Modified amines useful as scale inhibitors in wet process phosphoric acid production

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US3069225A (en) * 1960-01-27 1962-12-18 Gen Mills Inc Method of inhibiting corrosion
US3262791A (en) * 1960-08-04 1966-07-26 Petrolite Corp Corrosion preventing method and composition
US3239470A (en) * 1963-02-01 1966-03-08 Grace W R & Co Stabilizing filming amines
GB1133382A (en) * 1965-06-17 1968-11-13 W E Zimmie A G Method of preventing corrosion in water systems
US3654993A (en) * 1970-04-06 1972-04-11 Atlantic Richfield Co Method for inhibiting corrosion in a well
US3965027A (en) * 1974-03-11 1976-06-22 Calgon Corporation Scale inhibition and corrosion inhibition

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ATE15817T1 (en) 1985-10-15
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