DE3814055A1 - METHOD FOR INHIBITING CORROSION - Google Patents

Abstract

A method of inhibiting the corrosion of copper or of a metal containing copper, comprising contacting the surface of the copper, or copper containing alloy with a corrosion-inhibiting amount of a mixture of a compound having the formula A: <IMAGE> wherein R1 is C1-C19 straight- or branched chain alkyl, C5-C12 cycloalkyl, C7-C13 aralkyl, optionally substituted C6, C10 or C14 aryl, a monocyclic heterocyclic residue having up to 5 ring carbon atoms or a residue of formula I: -(CH2)n-CHO I where n=1-6: and a compound having the formula B R2NH2 B wherein R2 is C1-C19 straight or branched chain alkyl, C5-C12 cycloalkyl, C7-C13 aralkyl, optionally substituted C6, C10 or C14 aryl, a monocyclic heterocyclic residue having up to 5 ring carbon atoms or a residue of formula II: -(CH2)mNH2II

Description

The present invention relates to a method for inhibiting corrosion of copper and copper alloys and compositions, in contact standing with copper and its alloys, to inhibit corrosion, and the use of a combination of certain aldehydes and Amines as corrosion inhibitors for copper and copper alloys.

It is well known that copper surfaces are prone to corrosion are when such surfaces are in contact with an aqueous or non-aqueous medium come. Furthermore, the products of copper corrosion the decomposition of other organic media used in Are in contact with the corrosive surface, catalyze and can galvanically trigger the corrosion of other metals, e.g. B. of iron or aluminum, which may also be present.

Many connections of widely different structures are considered Copper corrosion inhibitors for use in media such as aqueous Systems or functional liquids.

Among many others, a type of compound comprising the Schiff bases from the condensation of aromatic amines and aromatic aldehydes, found to be very efficient. In "Surface Coatings and Technology ", 27, 175-86 (1986) becomes N- (2-mercaptophenyl) salicylidenimine as a corrosion inhibitor for copper in aqueous alcoholic Media described while in "Surface Coatings and Technology", 29, 141-151 (1986), the same molecule and its analogs as corrosion inhibitors described for copper and its alloys in an acid medium are.  

In previous publications, Schiff bases were described as metal corrosion inhibitors in a number of systems. Thus, in "J. Electrochem. Soc. India" 32, 397-401 (1983), N, N'-bis (2-hydroxybenzylidene) ethylenediamine and N, N'-bis (4-methoxybenzylidene) ethylenediamine are corrosion inhibitors for Zinc described in sulfamic acid; in US-PS 38 65 739 an alkylidene iminothiadiazole inhibitor is disclosed; in GB-PS 14 34 354 the azomethine, produced by the condensation of cinnamaldehyde and γ- aminocapronitrile, is described as an inhibitor for steel in hydrochloric acid.

GB-PS 8 03 541 for its part relates to a mixture of aldehydes and amines in acidic liquids, in particular for pickling, around metal to protect surfaces. The metals listed are iron and steel and aluminum and zinc according to the invention.

M. N. Desai mentioned in "Materials and Corrosion" 23rd year, Issue 6, 1972 on pages 483-487 various compounds as corrosion inhibitors for copper. Aldehydes and amines are listed, but are found in each Trap only used individually.

In contrast to this prior art, for example the Inhibition of metal corrosion by Schiff bases has been proposed Surprisingly found that mixtures of precursors of Schiff bases have an exceptional copper corrosion inhibition in different media, for example in functional liquids and aqueous systems.

Accordingly, the present invention shows a method for Containing corrosion inhibition on copper or a metal Copper, characterized by bringing the copper surface into contact or the surface of a copper-containing alloy with a corrosion inhibitory amount of a mixture of a compound of formula

where R₁ straight or branched chain C₁-C₁₉ alkyl, C₅-C₁₂ cycloalkyl, C₇-C₁₃ aralkyl, C₆, C₁₀ or C₁₄ aryl, substituted C₆, C₁₀ or C₁₄ aryl, a monocyclic heterocyclic radical with up to 5 ring C atoms or a radical of the formula

- (CH₂) _n -CHO (I)

where n = 1-6
and a compound of formula B

R₂-NH₂ (B)

where R₂ straight or branched chain C₁-C₁₉ alkyl, C₇-C₁₃ aralkyl, C₆, C₁₀ or C₁₄ aryl, substituted C₆, C₁₀ or C₁₄ aryl, a monocyclic heterocyclic radical having up to 5 ring C atoms or a radical of formula

- (CH₂) _m -NH₂ (II)

where m = 1-6.

If R₁ or R₂ represent alkyl radicals with 1 to 19 carbon atoms, then these are straight or branched and, for example, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-dodecyl, n-tridecyl, represent n-pentadecyl, n-heptadecyl or n-nonadecyl.

As C₅-C₁₂ cycloalkyl radicals R₁ or R₂ can, for example, cyclopentyl, Cyclohexyl, cyclooctyl, cyclodecyl, adamantyl or cyclododecyl.

As C₇-C₁₃ aralkyl radicals R₁ or R₂ can be benzyl, 2-phenylethyl, Be benzhydryl or naphthylmethyl.

C₆, C₁₀ or C₁₄ aryl radicals for R₁ or R₂ are phenyl, naphthyl or Anthracenyl. Possible substituents on these aryl radicals are e.g. B. Hydroxyl, amino, thiol, carbonyl, carboxyl, sulphoxyl or a group

where R₃ is hydrogen or hydroxyl.  

Heterocyclic radicals for R₁ and R₂ can, for. B. pyridyl, furfuryl or Be thiophene.

Preferred compounds of the formula (A) are those of the formula

wherein X is hydrogen, hydroxyl, thiol or a radical

wherein R₃ is hydrogen or hydroxyl.

Other preferred compounds are those of the formula

OHC (CH₂) _n CHO (A 2)

where n = 1-6.

Preferred compounds of the formula B are those of the formula

wherein Y is hydrogen, amino, hydroxyl, thiol, carboxyl or sulfoxyl.

Specific examples of compounds of formula A in the mixture of Connections include:

Acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, 2-ethylbu tyraldehyde, valeraldehyde, isovaleraldehyde, hexanoaldehyde, heptane aldehyde, Octylaldehyde, nonylaldehyde, decylaldehyde, undecylaldehyde, dodecylaldehyde, Tetradecylaldehyde, pentadecylaldehyde, hexadecylaldehyde, octadecylaldehyde, Eicosylaldehyde, cyclopentane carboxaldehyde, cyclohexane carboxaldehyde, Cyclooctane carboxaldehyde, cyclododecylcarboxaldehyde, phenylacetaldehyde, 3-phenylpropionaldehyde, benzhydrylcarboxaldehyde, naphthylacetaldehyde, Benzaldehyde, salicaldehyde, 3-hydroxybenzaldehyde, 4-hydroxybenzaldehyde, 2-mercaptobenzaldehyde, 3-mercaptobenzaldehyde, 4-mercaptobenzaldehyde,  Phthalaldehyde, isophthalaldehyde, terephthalaldehyde, 2-carboxybenzaldehyde, 4-carboxybenzaldehyde, 2-sulfobenzaldehyde, 4-sulfobenzaldehyde, 1-naphthaldehyde, 2-naphthaldehyde, 2-hydroxy-1-naphthaldehyde, 2-mercapto-1-naphthaldehyde, 1-anthracenaldehyde, 2-anthracenaldehyde, 2-hydroxy-1-anthracenaldehyde, Malonaldehyde, succinaldehyde, glutaraldehyde, adipinaldehyde, 1,5-hep tan-dicarboxaldehyde, 1,6-hexane-dicarboxaldehyde, furfural, thiophene-2- carboxaldehyde.

Specific examples of the compound of formula B include:

Methylamine, ethylamine, propylamine, isopropylamine, n-butylamine, sec-butylamine, tert-butylamine, n-amylamine, tert-amylamine, n-hexylamine, n-heptylamine, n-octylamine, 2-ethylhexylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, 1-hexadecylamine, 1-octadecylamine, cyclopentylamine, cyclohexylamine, cycloheptylamine, Cyclooctylamine, 1-adamantamine, cyclodexdecylamine, benzylamine, 2-phenylethylamine, benzhydrylamine, 3-phenylpropylamine, 4-phenylbutylamine, Naphthylmethylamine, aniline, 2-hydroxyaniline, 3-hydroxyaniline, 4-hydroxyaniline, 2-mercaptoaniline, 3-mercaptoaniline, 4-mercaptoaniline, 2-amino benzaldehyde, orthoaminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, Sulphanilic acid, 2-aminobenzenesulfonic acid, dimethylamine, 1,2-di ethylamine, 1,3-dipropylamine, 1,4-dibutylamine, 1,5-dipentylamine, 1,6-di hexylamine, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 1-naphth thylamine, 1-amino-2-naphthol, 1-amino-7-naphthol, 3-amino-2-naphthol, 4-amino-1-naphthol, 8-amino-2-naphthol, 3-amino-2-naphtholic acid, 2-amino no-1-naphthalenesulfonic acid, 4-amino-1-naphthalenesulfonic acid, 5-amino-2- naphthalenesulfonic acid, 8-amino-2-naphthalenesulfonic acid, 3-amino-2,7- naphthalenesulfonic acid, 7-amino-1,3-naphthalenesulfonic acid, 1-aminoanthracene, 2-aminoanthracene, 2-aminopyridine, 3-aminopyridine.

The method of treating the metal surfaces can be different Way.

For example, the copper surface can be in a film or coating, impregnated with sufficient amounts of the compounds of the formulas (A) and (B) be enveloped; or the copper surface can be in a solution, for example an aqueous solution containing sufficient amounts of  Compounds of the formulas (A) and (B). Usually is so that the metal surface is constantly in contact with a substrate stands, which causes corrosion on the metal surface. In such Cases can cause the surfaces of metals containing copper through the Add a corrosion inhibiting amount of a mixture of the compounds of formulas A and B are effectively inhibited against corrosion. In In all of the above procedures, the mixture can be non-equimolar amounts of A and B, for example in a ratio of 3: 1 to 1: 3, however, an equimolar mixture is preferred.

The present invention therefore also provides a composition Available containing a substrate in contact with copper or a Copper containing metal and a corrosion inhibiting amount, purpose moderately 0.001 to 5% by weight, preferably 0.01 to 1% by weight, based on the total weight of the substrate, a mixture of the compounds of the Formulas A and B as defined above.

Examples of substrates in accordance with the present invention can be treated include functional liquids, such as Lubricants, for example those containing a mineral oil Poly-alpha-olefin or a synthetic carboxylic acid ester base; hydraulic Liquids, such as those based on mineral oils, phosphate esters, aqueous polyglycol / polyglycol ether mixtures or glycol systems; Oil-in-water or water-in-oil systems; Metalworking fluids with mineral oil or aqueous systems as Base; on water or aqueous glycol or ethylene or propylene machine cooling systems based on glycol / methanol; Transformer or Switch oils; as well as aqueous systems, for example industrial ones Cooling water, aqueous air conditioning systems, steam generator systems, Sea water evaporation systems; hydrostatic heaters; and watery Closed loop heating or cooling systems.

If the functional liquid is a synthetic lubricant, so include examples of lubricants based on a diester one dibasic acid and a monohydric alcohol, for example dioctyl sebacat or dinonyl adipate; based on a triester of trimethyl propane and a monobasic acid or mixture of such acids,  for example trimethylolpropane tripelargonate, trimethylolpropane tricaprylate or mixtures thereof; based on a tetraester of pentaerythritol and a monobasic acid or mixtures of such acids, for example pentaerythritol tetracaprylate; or based on complex Made from monobasic acids, dibasic acids and esters polyhydric alcohols, for example complex esters made from Trimethylolpropane, caprylic acid and sebacic acid or mixtures thereof.

Other synthetic lubricants are the prior art and described, for example, in "Lubricant Paperback", Hüthig-Verlag, Heidelberg, 1974, "Ullmann’s Encyclopedia of Technical Chemie ", vol. 13, pages 85-94 (Verlag Chemie, Weinheim 1977) or in D. Klamann, "Lubricants and Related Products", pages 158-174 (Verlag Chemie, Weinheim 1982). Particularly suitable in addition to the preferred ones mineral oils, for example phosphates, polyglycols, poly alkylene glycols and polyalphaolefins.

To improve the various application properties, a functional liquid according to the present invention also other Additives contain, such as, for oil-based systems, one or several antioxidants, metal deactivators, other corrosion inhibitors or rust inhibitors, viscosity index improvers, pour point depressants, Dispersants, surface-active substances and / or High pressure additives and friction reducers and for water based Systems, one or more antioxidants, other corrosion and Rust inhibitors, metal deactivators, high pressure additives and friction reducing, complexing agents, precipitation inhibitors, biocides, buffering agents and / or anti-foaming agents.

Examples of other additives for systems based on oil are:

Examples of phenolic antioxidants 1. Alkylated monophenols

2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butylphenol, 2-tert-butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-iso-butylphenol, 2,6-di-cyclopentyl-4-methylphenol, 2- ( α- methylcyclohexyl ) -4,6-dimethylphenol, 2,6-di-octa decyl-4-methylphenol, 2,4,6-tri-cyclohexylphenol, 2,6-di-tert-butyl-4-methoxymethylphenol, o-tert-butylphenol .

2. Alkylated hydroquinones

2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butyl-hydroquinone, 2,5-di-tert-amyl hydroquinone, 2,6-diphenyl-4-octadecyloxyphenol.

3. Hydroxylated thiodiphenyl ether

2,2'-thio-bis- (6-tert-butyl-4-methylphenol), 2,2'-thio-bis- (4-octylphenol), 4,4'-thio-bis- (6-tert-butyl-3-methylphenol), 4,4'-thio-bis- (6- tert-butyl-2-methylphenol).

4. Alkylidene bisphenols

2,2'-methylene-bis- (6-tert-butyl-4-methylphenol), 2,2'-methylene-bis- (6-tert-butyl-4-ethylphenol), 2,2'-methylene-bis - [4-methyl-6- ( a -methylcyclohexyl) phenol], 2,2'-methylene-bis- (4-methyl-6-cyclohexylphenol), 2,2'-methylene-bis- (6-nonyl -4-methylphenol), 2,2'-methylene-bis- (4,6-di tert-butylphenol), 2,2'-ethylidene-bis- (4,6-di-tert-butylphenol), 2,2 '- ethylidene-bis- (6-tert-butyl-4- or -5-iso-butylphenol), 2,2'-methylene-bis- [6- ( α- methylbenzyl) -4-nonylphenol], 2.2 '-Methylene-bis- [6- ( α, α -di methylbenzyl) -4-nonylphenol], 4,4'-methylene-bis- (2,6-di-tert-butylphenol), 4,4'-methylene -bis- (6-tert-butyl-2-methylphenol), 1,1-bis- (5-tert-butyl-4-hydroxy-2-methylphenyl) butane, 2,6-di- (3-tert- butyl-5-methyl-2-hydroxybenzyl) -4-methylphenol, 1,1,3-tris (5-tert-butyl-4-hydroxy-2-methylphenyl) -3-n-dodecyl mercaptobutane, ethylene glycol bis- [ 3,3-bis (3'-tert-butyl-4'-hydroxyphenyl) butyrate], bis (3-tert-butyl-4-hydroxy-5-methylphenyl) dicyclopentadiene, bis- [2- (3rd 'Tert-butyl-2'-hydroxy-5'-methyl-benz yl) -6-tert-butyl-4-methylphenyl] terephthalate.

5. Benzyl compounds

1,3,5-tri- (3,5-di-tert-butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene, Bis (3,5-di-tert-butyl-4-hydroxybenzyl) sulfide, 3,5-di-tert-butyl-4- isooctyl hydroxybenzyl-mercaptoacetic acid, bis- (4-tert-butyl-3- hydroxy-2,6-dimethylbenzyl) dithiol terephthalate, 1,3,5-tris- (3,5-di- tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris- (4-tert-butyl-3-  hydroxy-2,6-dimethylbenzyl) isocyanurate, 3,5-di-tert-butyl-4-hydroxy dioctadecyl benzylphosphonate, 3,5-di-tert-butyl-4-hydroxy monoethyl benzyl phosphoric acid, calcium salt.

6. Acylaminophenols

4-hydroxy lauric anilide, 4-hydroxy stearic anilide, 2,4-bis-octyl mercapto-6- (3,5-di-tert-butyl-4-hydroxyanilino) -s-triazine, N- (3,5-di-tert- butyl-4-hydroxyphenyl) carbamic acid octyl ester.

7. Esters of β - (3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid

with mono- or polyhydric alcohols, such as. B. with Methanol, diethylene glycol, octadecanol, triethylene glycol, 1,6-hexanediol, Pentaerythritol, neopentyl glycol, tris-hydroxyethyl isocyanurate, thiodi ethylene glycol, bis-hydroxyethyl oxalic acid diamide.

8. Ester of β - (5-tert-butyl-4-hydroxy-3-methylphenyl) propionic acid

with mono- or polyhydric alcohols, such as. B. with Methanol, diethylene glycol, octadecanol, triethylene glycol, 1,6-hexanediol, Pentaerythritol, neopentyl glycol, tris-hydroxyethyl isocyanurate, thiodi ethylene glycol, di-hydroxyethyl oxalic acid diamide.

9. Amides of β - (3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid

such as B. N, N'-bis (3,5-di-tert-butyl-4-hydroxyphenylpropionyl) hexa methyl diamine, N, N'-bis (3,5-di-tert-butyl-4-hydroxyphenylpropionyl) - trimethyl diamine, N, N'-bis (3,5-di-tert-butyl-4-hydroxyphenylpropionyl) - hydrazine.

Examples of aminic antioxidants:

N, N'-di-isopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, N, N'-bis- (1,4-dimethyl-pentyl) -p-phenylenediamine, N, N'-bis- (1-ethyl-3- methyl-pentyl) -p-phenylenediamine, N, N′-bis- (1-methyl-heptyl) -p-phenylenediamine, N, N'-dicyclohexyl-p-phenylenediamine, N, N'-diphenyl-p-phenylenediamine, N, N'-di- (naphthyl-2) -p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine, N- (1-methyl- heptyl) -N'-phenyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine, 4- (p-toluenesulfonamido) diphenyldiamine, N, N'-dimethyl-N, N'-di-sec- butyl-p-phenylenediamine, diphenylamine, N-allyldiphenylamine, 4-isopropoxy  diphenylamine, N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine, octylated Diphenylamine, e.g. B. p, p'-di-tert-octyldiphenylamine, 4-n-butylaminophenol, 4-butyrylamino-phenol, 4-nonanoylamino-phenol, 4-dodecanoyl- amino-phenol, 4-octadecanoylamino-phenol, di- (4-methoxy-phenyl) -amine, 2,6-di-tert-butyl-4-dimethylamino-methyl-phenol, 2,4'-diamino-diphenyl- methane, 4,4'-diamino-diphenylmethane, N, N, N ', N'-tetramethyl-4,4'-diamino- diphenylmethane, 1,2-di - [(2-methylphenyl) amino] ethane, 1,2-di- (phenyl amino) propane, (o-tolyl) biguanide, di- [4- (1 ', 3'-dimethylbutyl) phenyl] amine, tert-octylated N-phenyl-l-naphthylamine, mixture of mono- and dialkylated tert-butyl / tert-octyldiphenylamines, 2,3-dihydro-3,3-di methyl-4H-1,4-benzothiazine, phenothiazine, N-allylphenothiazine.

Examples of other antioxidants

Aliphatic or aromatic phosphites, esters of thiodipropionic acid or thiodiacetic acid, or salts of dithiocarbamide or dithio phosphoric acid.

Examples of metal deactivators, e.g. B. for copper, are:

Triazoles, benzotriazoles and their derivatives, tolutriazoles and their Derivatives, 2-mercaptobenzthiazole, 2-mercaptobenztriazole, 2,5-dimercapto benztriazole, 2,5-dimercaptobenzthiadiazole, 5,5′-methylenebisbenztriazole, 4,5,6,7-tetrahydrobenztriazole, salicylidene-propylenediamine, salicylaminoguanidine and its salts.

Examples of rust inhibitors are:

• a) Organic acids, their esters, metal salts and anhydrides, e.g. B .: N-oleoyl sarcosine, sorbitan mono-oleate, lead naphthenate, akenyl succinic anhydride, e.g. B. dodecenylsuccinic anhydride, Alkenyl succinic acid partial esters and partial amides, 4-nonylphenoxy-vinegar acid.
• b) nitrogen-containing compounds, e.g. B .: I. Primary, secondary or tertiary aliphatic or cycloaliphatic Amines and amine salts of organic and inorganic Acids, e.g. B. oil-soluble alkyl ammonium carboxylates.

II. Heterocyclic compounds, e.g. B .:

Substituted imidazolines and oxazolines.

• c) phosphorus-containing compounds, e.g. B .: Amine salts of phosphoric acid partial esters or partial phosphonic acid esters, zinc dialkyldithiophosphates.
• d) Sulfur-containing compounds, e.g. B .: Barium dinonylnaphthalene sulfonates, calcium petroleum sulfonates.

Examples of viscosity index improvers are:

Polyacrylates, polymethacrylates, vinyl pyrrolidone / methacrylate copolymers, Polyvinylpyrrolidones, polybutenes, olefin copolymers, styrene / acrylate Copolymers, polyethers.

Examples of pour point depressants are:

Polymethacrylate, alkylated naphthalene derivatives

Examples of dispersants / surfactants are:

Polybutenyl succinic acid amides or imides, polybutenyl phosphonic acid derivatives, basic magnesium, calcium and barium sulfonates and -phenolates.

Examples of wear protection additives are:

Compounds containing sulfur and / or phosphorus and / or halogen, such as sulfurized vegetable oils, zinc dialkyldithiophosphates, tritolyl phosphate, chlorinated paraffins, alkyl and aryl di and tri sulfides, Triphenylphosphorothionate, diethanolaminomethyltolyltriazole, di (2-ethyl hexyl) aminomethyltolyltriazole.

When used in substrates that are completely aqueous, such as Water cooling systems, air conditioning systems, steam generation systems, Sea water evaporation systems, hydrostatic heaters and heating and Closed circuit cooling systems can be other corrosion inhibitors are used, such as water-soluble zinc salts, Phosphates, polyphosphates, phosphonic acid and their salts, such as. B. Hydroxyethylidenediphosphonic acid, nitrilotrismethylenephosphonic acid and  Methylaminodimethylenephosphonecarboxylic acid and its salts, as in described for example in DE-OS 26 32 774, hydroxyphosphonacetic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid and those as in the GB-PS 15 72 406 discloses nitrates, e.g. B. sodium nitrate, nitrites, e.g. B. Sodium nitrite, molybdates, e.g. B. sodium molybdate, tungstates, silicates, e.g. As sodium silicate, benzotriazole, bisbenzotriazole or copper desakti Fouring benzotriazole or tolutriazole derivatives or their Mannich bases derivatives, N-acylsarcosines, N-acyliminodiacetic acids, ethanolamines, Fatty amines and polycarboxylic acids, e.g. B. polymaleic acid and polyacrylic acid, as well as the corresponding alkali metal salts, copolymers of Maleic anhydrides, e.g. B. copolymers of maleic anhydride and sulfonated styrene, copolymers of acrylic acid, e.g. B. Copolymers of Acrylic acid and hydroxyalkylated acrylic acids and substituted derivatives of polymaleic and polyacrylic acids, as well as their corresponding ones Alkali metal salts, copolymers of maleic anhydride, e.g. B. copolymers of Maleic anhydride and sulfonated styrene, copolymers of acrylic acid, e.g. B. Copolymers of acrylic acid and hydroxyalkylated acrylic acids and substi tuated derivatives of polymaleic and polyacrylic acid and their copolymers.

Furthermore, in accordance with the present invention in completely aqueous systems a triazole copper corrosion inhibitor be applied. Dispersants and / or surfactants, e.g. B. polymerized acrylic acids (or their salts), phosphino polycarboxylic acids (as described and claimed in GB-PS 14 58 235), the cotelomeric compounds described in the EP-A 01 50 706, hydrolyzed polyacrylonitrile, polymerized Methacrylic acid and its salts, polyacrylamides and copolymers thereof Acrylic and methacrylic acids, lignin sulphonic acids and their salts, tannin, Naphthalene sulfonic acid / formaldehyde condensation products, starch and their Derivatives, cellulose, acrylic acid / low alkyl hydroxyacrylate copolymers, e.g. B. as described in US-PS 40 29 577, styrene / maleic anhydride Copolymers and sulfonated styrene homopolymers, e.g. B. as described in U.S. Patent 4,374,733, and combinations thereof, specific surfactants Agents such as B. 2-phosphonobutane-1,2,4-tricarboxylic acid, Acetodiphosphonic acid, hydrolyzed polymaleic anhydride and its  Salts, alkylphosphonic acid, hydroxyphosphonic acetic acid, 1-aminoalkyl-1,1- diphosphonic acids and their salts and alkali metal polyphosphates can can also be used.

Precipitants, such as alkali metal orthophosphates, carbonates; Oxygen scavengers such as alkali metal sulfites and hydrazines; Sequestrants such as Nitrilotriacetic acid and its salts; Anti-foaming agents, such as silicones, e.g. B. polydimethylsiloxanes, distearyl sebacamides, distearyl adipamide and related products made from ethylene oxide and / or propylene oxide Condensation in addition to fatty alcohols such as caprylic alcohol and its Ethylene oxide condensates, and biocides, e.g. B. amines, quaternary ammonium ver bonds, chlorophenols, sulfur-containing compounds, such as sulphones, Methylene bis-thiocyanates and carbamates, isothiazolones, brominated Propionamides, triazines, phosphonic compounds, chlorine and chlorine releasing Substances and organometallic compounds such as tributyltin oxide can be applied.

The compounds of the formulas A and B connect excellent copper deactivating properties with good solubility in aqueous or oil-based substrates.

The following examples illustrate the present invention continue. All parts and percentages given refer to the weight unless otherwise stated.

Examples 1 to 11

A 0.05% solution of an equimolar mixture of the compounds with The formulas A and B are in a 75:25 water: ethylene glycol mixture, in which the water 0.132 g / l MgSO₄ · 7 H₂O and 0.68 g / l CaCl₂ · 6 H₂O (water according to DIN 51 360 test). The pH of the solution is increased with NaOH 8.5 set.

A piece of copper foil (20 × 50 × 0.1 mm) is rubbed with a tree cotton wool, soaked with water and powdered pumice, rubbed off, dried and weighed. The film is then completely in 50 ml Solution, in a 60 ml bottle with screw cap, immersed. The bottle is placed in an oven at 70 ° C for 24 hours  held. After the time, the film is removed, washed and dried and their color determined (using ASTM D 130 Color scale). The film is then soaked in 5N hydrochloric acid for 15 seconds immersed at 20 ° C, washed, dried and weighed again.

The results are listed in Table 1:

The assessment takes place in levels 1 to 4 and within these levels in the subdivision with the designations a to d. Mean it excerpts from the ASTM D 130 standard:  

1 slightly matt 2 medium matt 3dark matt 4D corrosion Light orange, almost the same condition as the fresh one polished sample Dark orange Multicolored with lavender blue or silver Covered in an Amagenta color

Claims (14)

1. A method for inhibiting the corrosion of copper or a copper-containing metal, characterized in that the surface of the copper or copper-containing alloy with a corrosion-inhibiting amount of a mixture of a compound of formula wherein R₁ is a C₁-C₁₉ straight or branched chain alkyl, C₅-C₁₂ cycloalkyl, C₇-C₁₃ aralkyl, C₆, C₁₀ or C₁₄ aryl, substituted C₆, C₁₀ or C₁₄ aryl, a monocyclic heterocyclic radical with up to 5 ring C -Atoms or a radical of the formula - (CH₂) _n -CHO (I) in which n = 1-6, and a compound of the formula BR₂-NH₂ (B) where R₂ is a C₁-C₁₉ straight or branched chain alkyl radical, C₅-C₁₂- cycloalkyl, C₇-C₁₃-aralkyl, C₆, C₁₀ or C₁₄ aryl, substituted C₆, C₁₀ or C₁₄ aryl, a monocyclic heterocyclic radical with up to 5 ring C atoms or a radical of the formula (CH₂) _n -NH₂ (II) where n = 1-6, is brought into contact. 2. The method according to claim 1, characterized in that the compound of formula A has the formula having,
wherein X is hydrogen, hydroxyl, thiol or a group where R₃ is hydrogen or hydroxyl. 3. The method according to claim 1, characterized in that the compound of formula A has the formula OHC (CH₂) _n CHO (A 2),
where n is a number from 1 to 6. 4. The method according to any one of claims 1 to 3, characterized in that the compound of formula B has the formula having,
where Y represents hydrogen, amino, hydroxyl, thiol, carboxyl or sulphoxyl. 5. The method according to any one of claims 1 to 4, characterized in that the mixture A and B in a molecular ratio of 3: 1 to 1: 3 contains. 6. The method according to any one of claims 1 to 5, characterized in that that the mixture contains equimolar amounts of compounds A and B. 7. Composition containing a substrate in contact with copper or a metal containing copper and a corrosion inhibitor Amount of a mixture of the compounds of the formulas A and B according to Claim 1. 8. The composition of claim 7, which is 0.001 to 5 wt .-% based on the total weight of the substrate, a mixture of the compounds of the formula A and B. 9. The composition according to claim 8 containing 0.01 to 1 wt .-%, based on the total weight of the substrate, the mixture of the compounds of the formulas A and B.   10. The composition of claim 8 or 9, the equimolar amounts of Contains compounds of the formulas A and B. 11. The composition according to any one of claims 7 to 10, in which the Substrate a lubricant, a hydraulic fluid, an oil-in-water or water-in-oil system, a metalworking fluid Machine coolant, a transformer or switch oil, an industry cooling water, an aqueous air conditioning system, a steam generator system, a sea water evaporation system, a hydrostatic Heater or an aqueous closed circuit of a heating or Cooling system. 12. The composition according to claim 11, which is based on oil and additionally an antioxidant, metal deactivator, corrosion or rust inhibitor, Viscosity index improvers, pour point depressants, dispersants, contains surfactant and / or friction reducer. 13. The composition according to claim 11, which is based on water and additionally an antioxidant, a corrosion or rust inhibitor, one Metal deactivator, a high pressure additive or friction reducer Complexing agent, a precipitation inhibitor, biocide buffering substances and / or contains an anti-foaming agent. 14. Use of a combination of compounds of the formulas (A) and (B) according to claim 1 as a corrosion inhibitor for copper or copper alloys.