EP1187883A1

EP1187883A1 - Chromium-free anticorrosive and anticorrosive method

Info

Publication number: EP1187883A1
Application number: EP00935006A
Authority: EP
Inventors: Stefan Küpper; Jörg Sander; Karsten Hackbarth; Christina Hirsch; Veit Lachmann; Petra Reessing; Reinhard Seidel
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 1999-05-20
Filing date: 2000-05-11
Publication date: 2002-03-20
Also published as: CA2374539A1; AU5065600A; WO2000071626A1; AU780777B2; DE19923084A1

Abstract

The invention relates to a chromium-free aqueous anticorrosive which is suitable for producing thin organic layers on surfaces of steel, metallized (e.g. galvanized or alloy-galvanized) steel and aluminum. The inventive anticorrosive contains as the essential components a) 0.5 to 100 g/l hexafluorine anions of titanium (IV), silicon (IV) and/or zirconium (IV); b) 20 to 100 g/l phosphoric acid; c) 0 to 100 g/l of one or more compounds of cobalt, nickel, vanadium, iron, manganese, molybdenum or tungsten; d) 0.5 to 30 wt.- %. of at least one water-soluble or water-dispersible film-forming organic polymer or copolymer; e) 0.1 to 10 wt.- % of an organosphonic acid; f) optionally further auxiliaries and additives. The inventive compositions are especially useful for the anticorrosive treatment of metal strips. They are preferably applied in such a manner that a dry layer is produced on the surface in a mass surface density of 0.1 to 5 g/m<2>.

Description

"Chromium-free corrosion protection agent and corrosion protection process"

The present invention relates to a chromium-free organic / inorganic corrosion protection agent and a corrosion protection method for the treatment of surfaces made of steel, which are optionally provided with a metallic coating of zinc, aluminum, copper, nickel, etc., or of aluminum and its alloys. It is particularly suitable for top surface treatment in coil systems (coil coating) for the use of these substrates in the household and architecture sector and in the automotive industry.

For the temporary corrosion protection of galvanized or alloy-galvanized steel strips, these are often either simply oiled with corrosion protection oils or if higher ones are to be expected

Corrosion stresses phosphated or chromated. Before the final coating with organic binders (primers, lacquers, electrophoretic lacquers), a multi-stage process usually follows. For the use of galvanized metal strip or aluminum and its alloys in the household appliance and architecture industry, the metal surface is first provided with a corrosion protection layer, if necessary after removing the oil layer beforehand. The best corrosion protection measure known in the prior art is chromating, in which the metal surface is coated with a chromium (III) and / or chromium (VI) -containing layer with generally about 5 to 15 mg / m ² chromium. Phosphating as an alternative measure to temporary corrosion protection has two disadvantages: First, the appearance of the metal surfaces can be changed in an undesirable manner. On the other hand, phosphating is very complex in terms of plant technology, since depending on the substrate material it requires an additional activation step and, as a rule, a passivation step after phosphating. In addition to the actual corrosion protection, the inorganic Coating adheres well to the primer applied to it. The primer in turn not only has a favorable effect on the corrosion protection effect of the inorganic conversion layer, the primer layer in turn offers the top coat a good basis for adhesion.

To an increasing extent, sheet finishers are also supplying sheets with a functional pre-coating that facilitate mechanical processing such as punching, drilling, folding, profiling and / or deep drawing. Only after the final assembly of the workpiece is it finally provided with a top coat. In addition to the corrosion-inhibiting properties, the functional pre-coating must also give the sheet mechanical properties. Methods for the production of these layers are known on the basis of chromium-containing inorganic / organic compositions and chromium-free, exclusively organic preparations, the latter having only a limited corrosion protection effect.

In the automotive industry, galvanized steel sheet pre-coated with thin organic films is increasingly used. This substrate ensures good protection against corrosion, even in areas of the body that are difficult or impossible to access in the normal painting process. By using such precoated materials, cost-intensive secondary corrosion protection measures such as cavity sealing and seam sealing can be reduced or saved entirely. To facilitate the subsequent processing steps, such as spot welding or electrocoating, the organic films often also contain pigments and fillers which increase the electrical conductivity. Such materials are known for example under the names Durasteel ™, Bonazinc ™, Durazinc ™ or Granocoat ™. Materials coated in this way have a thin organic coating over a conversion layer, for example a chromating or phosphating layer, which consists, for example, of binders on epoxy or polyurethane resins, polyamides or polyacrylates. The organic layers are generally applied in a thickness of approximately 0.3 to approximately 5 μm. This coating of the metal strips is generally carried out in a two-stage process which is complex in terms of plant technology, in which the inorganic conversion layer is first produced and then the organic polymer film is applied in a second treatment stage.

Attempts are already known to use single-stage coating processes in which the inorganic conversion treatment and the coating with an organic polymer film take place in a single treatment solution.

For example, US-A-5 344 504 describes a coating process for galvanized steel, in which the substrate is brought into contact with a treatment solution having the following composition: 0.1 to 10 g / l of a tetrabz. Hexafluoro acid of boron, silicon, titanium and zircon or hydrofluoric acid, about 0.015 to about 6 g / l cations of cobalt, copper, iron, manganese, nickel, strontium or zinc and optionally up to about 3 g / l of a polymer selected from polyacrylic acid, Polymethacrylic acid and its esters. The pH of this treatment solution is in the range from about 4 to about 5.

WO 95/14117 also describes a method for treating surfaces made of zinc or aluminum or their alloys. The surfaces are brought into contact with a treatment solution with a pH value below 3, which contains a complex between a metal oxoion and a heteroion. The metal oxoion is selected from molybdate, tungstate and vanadate. The heteroion is selected from phosphorus, aluminum, silicon, manganese, magnesium, zirconium, titanium, tin, cerium and nickel. The treatment solution also contains an organic film former which is compatible with the other components of the solution. Examples of suitable film formers are polyacrylates, such as, in particular, polymers of methyl methacrylate, n-butyl acrylate, hydroxyethyl acrylate and glycerol propoxy triacrylate. EP-A-694 593 recommends treating the metal surfaces with a treatment solution which contains the following components: an organic polymer or copolymer in which 0.5 to 8% of the monomers carry groups which can form compounds with metal ions, complex cations or Anions of aluminum, calcium, cerium, cobalt, molybdenum, silicon, vanadium, zircon, titanium, trivalent chromium and zinc, an oxidizing agent such as nitric acid, perchloric acid or hydrogen peroxide and an acid such as oxalic acid, acetic acid, boric acid, phosphoric acid, sulfuric acid, nitric acid or Hydrochloric acid.

WO 95/04169 teaches the treatment of metal surfaces with a treatment solution which contains at least the following components: fluorocomplexes of titanium, zirconium, hafnium, silicon, aluminum and boron, metal ions selected from cobalt, magnesium, manganese, zinc, nickel, tin, copper , Zircon, iron and strontium, phosphates or phosphonates and water-soluble or water-dispersible organic film formers.

EP-A-792 922 describes a chromium-free corrosion-inhibiting coating composition for aluminum or aluminum alloys which contains a film-forming organic polymer and (i) a salt selected from esters of rare earth metals, alkali or alkaline earth metal adadate and furthermore (ii) a borate salt of an alkaline earth metal. Examples of preferred polymers are epoxides, including polyimide-based epoxies, polyurethanes, acrylic polymers and alkyd-based systems. In addition to the organic film former, this coating composition must therefore contain at least one borate and a further component, which can be a vanadate.

EP-A-685534 describes a method for protecting a steel substrate by means of a thin film of an organic-inorganic hybrid polymer based on an alkoxysilane, another condensable one Organometallic compound of the formula M (OR) ₄ and (meth) acrylic acid and a polymerization initiator described. The coating is effected by thermal or photopolymerization. Zircon and titanium are mentioned as metals for the organometallic compound. Such a film is said to protect steel substrates from corrosion and oxidation, and also to protect the substrate from shock and other effects.

WO 98/47631 describes a method for repairing defective pretreated metal surfaces. For this purpose, an aqueous acidic solution containing fluorometalate anions, divalent or tetravalent cations of cobalt, magnesium, manganese, zinc, nickel, tin, copper, zirconium, iron and strontium is applied to the defective metal surfaces; Phosphorus-containing inorganic oxo anions and phosphonate anions and a water-soluble and / or water-dispersible organic polymer and / or a polymer-forming resin. The document makes no statement as to whether such compositions are also suitable for the first coating of non-precoated metal strip.

The as yet unpublished DE-A-1 9754108.9 describes a chrome-free aqueous corrosion protection agent for the treatment of surfaces made of galvanized or alloy-galvanized steel and aluminum. As essential components, it contains hexafluoro anions of titanium and / or zirconium, vanadium ions, cobalt ions, phosphoric acid and preferably also an organic film former, in particular based on polyacrylate. This anti-corrosion agent is particularly suitable for the anti-corrosion treatment of metal strips.

DE-A-4412138 describes a process for producing chromium-free conversion layers on the surface of aluminum and its alloys in the no-rinse process. There the treatment of the surfaces with aqueous solutions is disclosed which contain titanium and / or zirconium as well as a Orthophosphate, fluorides and 0.15 to 1.5 g / l of a water-soluble or homogeneously dispersible organic film former. After these compositions have dried, a solid film with a mass per unit area of about 50 to 350 mg / m ² remains on the metal surface. Larger layer thicknesses, in particular with a predominant proportion of organic film-forming agents, are not disclosed.

US-A-5449415 describes a chrome-free conversion coating especially for cold-rolled steel, which contains a component made of titanium, zirconium, hafnium, silicon and boron anions and a cation component made of cobalt, magnesium, manganese and similar heavy metals and a sufficient one Amount of free acid to ensure a pH in the range between 0.5 and 5.0. Furthermore, these compositions contain inorganic phosphorus-containing oxyanions or phosphonate anions and a small proportion of water-soluble or water-dispersible organic polymers and polymer-forming resins. The ratio of the polymers or polymer-forming resins to the inorganic anions of the coating should be in the range 1: 2 to 3: 1. Coating thicknesses between 5 and 500 mg / m ² (area-related mass of the dry film) can be achieved in this way. Larger layer thicknesses cannot be achieved with this coating composition.

US-A-5427632 describes very similar compositions to the aforementioned, with the difference that they still contain a dissolved oxidizing agent and can contain anti-settling agents. Even after the teaching of this document, no higher layer thicknesses of the coating are disclosed.

DE-A-19654642 describes aqueous solutions for treating metallic surfaces and processes for their use. This aqueous solution should contain one or more compounds of the type XYZ, where Y is an organic group with up to 50 C atoms and X is a carboxylic acid, sulfone, sulfate, phosphonate or phosphate group and Z is a functional group such as OH , SH-, NH ₂ - the CN group. Such connections are ^' also referred to as SAM compounds (Seif Assembling Molecule). They only allow very thin layer thicknesses of the coatings in the practically monomolecular range, that is to say layer thicknesses of 5 to 10 nm are typically achieved in this way.

Despite the extensive state of the art, there is still a need for improved coating processes for metal surfaces in which an inorganic passivation layer and, in the same treatment step, a thin organic polymer layer are additionally applied to the metal surfaces. Thin organic polymer layers are to be understood here to mean significantly thicker layers than are known from the aforementioned prior art. Nevertheless, the coating should enable and even facilitate the punching and forming of the components from the coated metal strips. Furthermore, the layers of the metal substrates should survive the further production steps up to the assembly of the products, such as cleaning, possibly phosphating, riveting, welding, and either be able to be painted directly with a topcoat or be coatable by electrocoating. For reasons of environmental protection and occupational safety, the treatment process should be able to be carried out without the use of chromium compounds and, if possible, with the exclusion of organic solvents. The main fields of application are the household appliance and architecture industries mentioned above, as well as the automotive industry.

The solution to the problem according to the invention can be found in the patent claims. It consists essentially in the provision of a chromium-free corrosion protection agent containing water and

a.) 0.5 to 100 g / l hexafluoro anions of titanium (IV), Siiicium (IV) and / or zircon

(IV) b.) 0 to 100 g / l phosphoric acid c.) 0 to 100 g / l of one or more compounds of cobalt, nickel,

Vanadium, iron, manganese, molybdenum or tungsten. d.) 0.5 to 30% by weight of at least one water-soluble or water-dispersible film-forming organic polymer or copolymer (based on active substance), e.) 0.1 to 10% by weight of an organophosphonic acid f.) optionally further auxiliaries and additives .

The invention further relates to a method for the corrosion-protecting treatment of steel, which is optionally provided with a metallic coating of zinc, aluminum, copper, nickel or similar metals, or aluminum or its alloys, which includes the following essential process steps:

a) the surface of the substrate is brought into contact with a corrosion protection agent of the type mentioned above for a period of time between 0.5 and 60 seconds at a treatment temperature between 10 and 50 ° C, preferably 15 and 35 ° C; the treatment temperature can be set by supplying heat via the workpiece or the treatment solution, b) the excess anticorrosive agent is removed from the surface, if necessary, and c) is heated for a period of 1 to 120 seconds by suitable supply of heat, with peak metal temperatures between 50 ° C and 150 ° C should be reached, at the same time a crosslinking of the polymeric film and its anchoring on the metal surface takes place.

The anti-corrosion agent is preferably applied to the workpiece, preferably metal strip surface, by flooding / squeezing, spraying / squeezing, suitable scraper or roller applications.

The preferred concentration ranges of components a) to e) of

Corrosion protection agents are: a) 5-50 g / l hexafluoro anions of titanium (IV), silicon (IV) and / or zircon (IV), b) 0-50 g / l phosphoric acid, c) 0-40 g / l ions of cobalt, nickel, vanadium, iron, manganese, molybdenum, tungsten, d) 5-30% by weight of one or more film-forming organic polymers or copolymers (based on the active substance) e) 0.1-10% by weight of an organophosphonic acid.

The aforementioned concentration ranges of components a) to e) should preferably be chosen so that the ratio of polymer component d) to inorganic anion component a) is greater than 3.1. This enables “thick layers”, the majority of the layer obtained being the organic polymer. “Thick layers” in the sense of this invention have area-based masses of the coating after drying of between 0.1 and 5 g / m ² .

The pH of the anticorrosive agent is in the range from 0.5 to 4.0, preferably in the range from 0.7 to 2.5. Such an acidic agent dissolves the metal surfaces to be treated, so that a treatment bath which has been in use for some time can additionally contain cations which originate from the treated metallic substrates. Examples include zinc, aluminum, iron, nickel, silicon, lead and copper.

^'Those skilled in the art will appreciate that the above-mentioned components, in particular the inorganic compounds, can undergo reactions with each other so that they are present in the treatment solution in the form, which are stable under the conditions mentioned for the pH. For example, some of the hexafluoro anions will be in the form of the free acid.

A large number of compounds are suitable as film-forming organic polymers or copolymers, but they must satisfy two essential selection criteria: firstly, they must be present in the strongly acidic aqueous solution, the also contains polyvalent inorganic ions, be soluble or dispersible in sufficient concentration without coagulation and / or precipitation of the polymeric constituents. On the other hand, they must contain at least partially crosslinkable groups which allow the polymer layer to be sufficiently crosslinked in a short time by the application of heat and to be adhesively bonded to the substrate.

Specific examples of the film-forming polymers are epoxy resins, aminoplast resins (e.g. melamine-formaldehyde resins, urea

Formaldehyde resins), tannins, phenol-formaldehyde resins, polymers of vinyl phenol with sufficient alkyl or substituted alkyl aminomethyl groups on the phenolic ring to ensure water solubility or water dispersibility of the polymer. Further examples are water-soluble or water-dispersible polyurethane polymers, acrylate homo- and especially copolymer dispersions, methacrylate homo- and / or copolymer dispersions as well as butadiene copolymer dispersions or styrene copolymer dispersions. In particular, the copolymers based on olefinically unsaturated monomers can contain crosslinkable comonomers known per se. Examples include acrylic acid, methacrylic acid, glycidyl (meth) acrylate, acrylamide, N-methylolacrylamide, N, N-bis-alkoxymethyl (meth) acrylamide and similar thermally crosslinkable groups, where the alkoxy group can have 1 to 4 carbon atoms. Crosslinkers known per se can also be used in the form of epoxy resins, urea derivatives, or (blocked) polyisocyanates or their oligomeric derivatives. Self-crosslinking or externally crosslinkable (meth) acrylate dispersions or emulsions or their combination with epoxy resins and / or copolymers of 4-hydroxystyrene are particularly preferred. The latter copolymers can be represented by the following general formula: y- (R ¹ -NR ² - aminomethyl) -4-hydroxystyrene, where y 2, 3, 5 or 6 and R ^{1 is} an alkyl group with 1 to 4 carbon atoms , preferably a methyl group and R ^{2 can be represented} by the following general formula: H (CHOH) _n CH ₂ -, where n is an integer between 1 and 7, preferably between 3 and 5. The Average molecular weight of the aforementioned polymers is usually in the range between 600 and 20,000, preferably between 800 and 6,000. The molecular weights of water-soluble polymers are more likely to be found in the lower range, while the molecular weights of water-dispersible polymers are generally found in the middle to upper range. Further suitable film-forming organic (co) polymers are mentioned in T. Brock, M. Groteklaes, P. Miscke, "Textbook of coating technology", Vincentz-Verlag, 1998 in chapter 2.1.4 and chapter 3.5. The binders mentioned there are express Part of this registration.

Another important component of the compositions are organophosphonic acids, specific examples are the following phosphonic acids and diphosphonic acids:

1-hydroxy-1 phenylmethane-1, 1 diphosphonic acid

1 -hydroxy-1-phenylmethane-1, 1-diphosphonic acid ^■ 2 H ₂ 0 p-hydroxyphenyl-1 -aminomethane-1, 1-diphosphonic acid p-hydroxyphenyl-1-hydroxymethane-1, 1-diphosphonic acid ^■ H ₂ 0

1-Hydroxy-1 phenylmethane-1, 1-diphosphonic acid ^■ H ₂ O, Na ₂ - salt

1 -hydroxyphenylmethane-1, 1-diphosphonic acid ^• H ₂ O

1-Amino-1 phenylmethane-1, 1-diphosphonic acid

4-aminophenyl-1 hydroxymethane-1, 1-diphosphonic acid ^■ H ₂ 0 p-aminophenyl-1-aminomethane-1, 1-diphosphonic acid p-chlorophenylmethane -1, 1-diphosphonic acid

1 -Chlor -1-phenylmethane-1, 1-diphosphonic acid ^■ 2 H ₂ O p-chlorophenyl-1-hydroxymethane-1, 1-diphosphonic acid ^■ 2 H ₂ 0

1-chlorophenylmethane -1, 1-diphosphonic acid ^• H ₂ 0 p-chlorophenyl-1-chloromethane -1, 1-diphosphonic acid

4-chlorophenyl-1-chloromethane diphosphonic acid ^• 2 H ₂ O p-hydroxyphenylaminomethylene diphosphonic acid, disodium salt p-hydroxyphenyl -1- aminomethane-1, 1-diphosphonic acid, containing methylol

3,4-dimethylphenyl-1-chloromethane diphosphonic acid , 4-dimethylphenyl-1-hydroxymethane diphosphonic acid, 4-dimethylphenylaminomethane diphosphonic acid, 4-dimethylphenyl-1-chloromethane -1,1-diphosphonic acid ^■ 2 H ₂ O, -dimethylaminophenyl-1-hydroxymethane diphosphonic acid - (N-benzyl-N, N-dimethylamino) -phenyl-1 hydroxymethane-diphosphonic acid -trimethylaminophenyl-1-hydroxymethane-diphosphonic acid 3,4,5-trimethoxyphenyl-1 -aminomethane-1,1-diphosphonic acid 1-bis (N-hydroxymethyl) -amino-1 -phenylmethane -1,1-diphosphonic acid 3 , 5-dichloro-4-hydroxyphenyl-hydroxymethane diphosphonic acid 3,5-dibromo-4-hydroxyphenyl-aminomethane diphosphonic acid 1-amino-1-cyclohexylmethane-1, 1-diphosphonic acid 1 -hydroxy-1 -cyclohexylmethane-1, 1 -diphosphonic acid, sodium salt 1 -Hydroxy-1 -cyclohexylmethane-1, 1-diphosphonic acid, trisodium salt [4- (aminomethyl) -cyclohexyl] -1-hydroxymethane-1, 1 -diphosphonic acid 4-methoxybenzoylacetonitrile, phosphonylated N - (hydroxymethyl) -1-aminoethane -1, 1-diphosphonic acid 1, 3-diaminopropane -1, 1-diphosphonic acid 3-dimethy lamino-1 - aminopropane -1,1- diphosphonic acid 3- monomethylamino -1- aminopropane -1,1-diphosphonic acid 3- (N-dodecylamino) -1-aminopropane-1,1-diphosphonic acid 3- (N, N-dodecylmethylamino) -1-aminopropane-1,1-diphosphonic acid 3- (N-dodecylamino) -1-aminopropane-1,1-diphosphonic acid ^• HX (X = halogen) 3- (N-dimethyldodecylamino) -1-aminopropane-1,1 diphosphonic acid ^• methyl iodide 2-amino-2-methyl-1-hydroxypropane-1, 1-diphosphonic acid 3-amino-1-hydroxy-3-phenylpropane -1, 1-diphosphonic acid 3-amino-3-phenyl-1-hydroxypropane-1 , 1 -diphosphonic acid 3-diethylamino-1-hydroxypropane-1, 1-diphosphonic acid 3-N, N-dimethylamino-1-hydroxypropane-1, 1 diphosphonic acid 3-N-bis- (hydroxyethyl) -amino-1-hydroxypropane-1 , 1-diphosphonic acid 3- (N-dodecylamino) -1-hydroxypropane-1, 1-diphosphonic acid 1, 3-dihydroxy-3-phenylpropane-1, 1-diphosphonic acid 3-N, N-dimethyaminopropionic acid ^■ HCI -Dimethylamino-1-hydroxypropan-1, 1-diphosphonic acid, sodium salt

1, 3-dihydroxypropane-1, 1-diphosphonic acid, disodium salt

1-hydroxy-3-diethylaminopropane -1, 1-diphosphonic acid, sodium salt

1, 3-dihydroxy-3-phenylpropane-1, 1-diphosphonic acid, disodium salt

1,3-diaminobutane-1,1-diphosphonic acid

1-Hydroxy-3-aminobutane -1, 1-diphosphonic acid

3-monoethylamino-1-aminobutane-1, 1-diphosphonic acid -amino -1-hydroxybutane -1,1- diphosphonic acid -N, N-dimethylamino-1-hydroxybutane -1, 1-diphosphonic acid

6-amino -1-hydroxyhexane -1, 1-diphosphonic acid

1, 6-dihydroxyhexane-1, 1 - diphosphonic acid

1, 6-dihydroxyhexane -1, 1-diphosphonic acid, disodium salt

1, 11 -Dihydroxyundecan -1, 1-diphosphonic acid

11-Amino -1-hydroxyundecane -1, 1-diphosphonic acid n - propylphosphonic acid

Butyl -1-phosphonic acid

Hexyl -1-phosphonic acid

Octyl-1-phosphonic acid

Decane-1-phosphonic acid

Dodecyl-1 - phosphonic acid

Tetradecyl-1 - phosphonic acid

Octadecyl-1 - phosphonic acid

Octadecane monophosphonic acid, sodium salt

Eicosan monophosphonic acid, sodium salt t-1, 2-diaminocyclohexane tetrakis (methylenephosphonic acid)

Glucamine - bis (methylenephosphonic acid)

Glucamine - bis (methylenephosphonic acid), sodium salt

1-ureidoethane -1,1-diphosphonic acid methylenephosphonylated uramil

Pyrimidyl-2-aminomethane diphosphonic acid

Pyridyl-2-aminomethylene diphosphonic acid

N, N '- dimethylureidomethane diphosphonic acid N- (2-hydroxyethyl) ethylenediamine -N.N'.N'- trismethylenephosphonic acid

N- (2-hydroxyethyl) ethylenediamine -N.N'.N'- trismethylenephosphonic acid ^■ H ₂ O

Aminoacetic acid-N, N-dimethylenephosphonic acid

1, 2-diaminopropane tetrakis (methylenephosphonic acid)

2-hydroxypropane-1,3-diametetrakis (methylenephosphonic acid)

5-hydroxy-3-oxa -1- aminopentane-bis- (methylenephosphonic acid)

Imino-bis- (methylenephosphonic acid)

Imino-bis (methylenephosphonic acid) nitrosamine

Nitrosamine of imino-bis- (methylenephosphonic acid), disodium salt γ, γ-diphosphono-N-methylbutyrolactam

Amidinomethylene diphosphonic acid

Formylaminomethane diphosphonic acid

2-lminopiperidone-6,6-diphosphonic acid ^• H ₂ O

2-iminopyrrolidone-5,5-diphosphonic acid

N, N'-dimethyliminopyrrolidone-5,5-diphosphonic acid

1-methyl-2-pyrrolidone-5,5-diphosphonic acid

Aminodiacetic acid-N-methylphosphonic acid

1,3-dihydroxy-2-methylpropane-N, N-dimethylenephosphonic acid

1, 2-Dihydroxypropan-3-amino-bis (methylenephosphonic acid)

2-hydroxypropane-1,3-diametetrakis (methylenephosphonic acid)

3,6-dioxa -1, 8-diaminooctane - tetrakis (methylenephosphonic acid)

1, 5-diaminopentantetrakis (methylenephosphonic acid)

Methylamino - dimethylenephosphonic acid

N-hexylamino dimethylene phosphonic acid

Decyiamino-dimethylenephosphonic acid

3-picolylaminodimethylenephosphonic acid ^■ H ₂ 0

Methanephosphonic acid

Methane diphosphonic acid

Methane diphosphonic acid ^• H ₂ O, disodium salt

Dichloromethane diphosphonic acid ^• 5 H ₂ O, disodium salt

Dichloromethane diphosphonic acid tetraisopropyl ester

1, 1-diphosphonethane-2-carboxylic acid - Ethane -1, 1-diphosphonic acid

Ethane -1, 1-diphosphonic acid, tetrasodium salt

Ethane -1,2-diphosphonic acid

Ethane -1, 1,2-triphosphonic acid

Ethylene diphosphonic acid, tetrasodium salt

1, 2-diphosphonethane -1, 2-dicarboxylic acid

1, 2-diphosphonethane -1, 2-dicarboxylic acid ^• 2 H ₂ O

Ethane -1, 1 - 2,2-tetraphosphonic acid ^■ H ₂ O, hexaguanidine salt

Ethane -1, 1, 2,2-tetraphosphonic acid, hexaguanidine salt

Ethane -1, 1, 2,2-tetraphosphonic acid, guanidine salt

1 -phosphonoethane -1, 2,2- tricarboxylic acid, potassium salt

Phosphonoacetic acid α-chloro -α- phosphonoacetic acid α-phosphonoacetic acid

1-phosphonopropane-2,3-dicarboxylic acid

1 -phosphonopropane-1, 2,3-tricarboxylic acid, pentasodium salt

1 -phosphonopropane-1, 2,3-tricarboxylic acid ^• H ₂ O

Propane -1, 1, 3,3-tetraphosphonic acid, hexasodium salt

Aminomethane diphosphonic acid

Dimethylaminomethane diphosphonic acid

N-decylaminomethane -1, 1-diphosphonic acid

N-decylaminomethane diphosphonic acid

N, N-dimethylaminomethane diphosphonic acid monohydrate

Dimethylaminomethane diphosphonic acid, disodium salt

N-decylaminomethane diphosphonic acid, tetrasodium salt

1-Aminoethane-1, 1-diphosphonic acid

1-amino-2-chloroethane -1, 1-diphosphonic acid

1-Amino-2-phenylethane -1, 1-diphosphonic acid

1-Monomethylaminoethane-1, 1-diphosphonic acid

N-monohydroxymethylaminoethane-1,1-diphosphonic acid

1-aminopropane -1, 1-diphosphonic acid

1-aminopropane-1, 1, 3-triphosphonic acid 1-aminobutane-1, 1-diphosphonic acid 1-aminohexane-1, 1-diphosphonic acid 1-aminodecane-1, 1-diphosphonic acid 1-amino hexadecane -1, 1-diphosphonic acid 1-isononanoylamido -1,1-dimethylmethanephosphonic acid stearic acid amido -1, 1 - dimethylene methanephosphonic acid coconut fatty acid amido -1, 1-dimethylene methanephosphonic acid isononanoic acid amido -1,1- diethylmethanephosphonic acid 1-aminohexyl -1-phosphonic acid 1-amino octyl -1-phosphonic acid 1-hydroxyoctyl -1-phosphonic acid 1-hydroxydecyl -1-phosphonic acid 1-aminodecyl -1- phosphonic acid 1 -hydroxydecyl / dodecyl -1- phosphonic acid 1 -hydroxy-1-dodecyl -1-phosphonic acid 1 -hydroxy-dodecane -1- phosphonic acid

1-hydroxy-3,6,9-trioxadecane -1, 1-diphosphonic acid, trisodium salt 12-hydroxy-12-phosphonostearic acid, sodium salt cocosalkylaminobis (methylenephosphonic acid) phosphonylated polyglycol diacid

4- ethyl -4- methyl -3- oxo -1- aminohexane -1, 1-diphosphonic acid 1-hydroxy-3-oxo -4- ethyl -4-methylhexane -1, 1-diphosphonic acid 1-amino -4- ethyl - 4-methyl-3-oxohexane -1, 1-diphosphonic acid 1-hydroxy-3-oxo -4-ethyl -4-methylhexane -1, 1-diphosphonic acid ^• 1 H ₂ O, Na salt

4-ethyl -4-methyl-3-oxohex-1-ene -1, 1-diphosphonic acid 4-methyl -4-ethyl-3-oxohex-1-ene -1, 1-diphosphonic acid, sodium salt 1-amino - 3- oxo -4,4- dimethylheptane -1,1- diphosphonic acid 1-hydroxy -3- oxo -4,4- dimethylheptane -1, 1- diphosphonic acid ^■ H ₂ O, Na salt 4,4-dimethyl-3- oxo-hept -1- en -1, 1-diphosphonic acid 4,4-dimethyl-3-oxo-hept -1- en -1,1- diphosphonic acid, Na salt 1 -amino -3- oxo -4,4- dimethyldecane -1,1- diphosphonic acid Aminomethane monophosphonic acid

Tolylaminomethanephosphinic acid p-hydroxyphenyl -1 -aminomethanephosphonic acid semihydrochloride

N- ethylamino (phenylmethane diphosphonic acid)

1 -Benzylamino -1- phenylmethane -1- phosphonic acid

1-hydroxyethane monophosphonic acid

1-hydroxyethane -1- monophosphonic acid, disodium salt

1-hydroxyethane-1,1-diphosphonic acid (HEDP)

2- [Benzimidazolyl- (2,2) -] - ethanediphosphonic acid monohydrate

2- [benzimidazolyl- (2.2) -] - ethanediphosphonic acid

N-carboxymethane -1 - aminoethane -1, 1-diphosphonic acid

1, 5-diaminopentane -1, 1, 5,5-tetraphosphonic acid trihydrate α-octadecyl-phosphonosuccinic acid α-N-dodecylaminobenzylphosphonic acid ß-trifluoromethyl-ß-phosphonobutyric acid

1 -decylpyrrolidone -2,2- diphosphonic acid

Pyrrolidone -5,5- diphosphonic acid

2,2-diphosphono -N-decylpyrrolidone γ, γ-diphosphono -N-methylbutyrolactam

Benzenephosphonous acid

1,4-thiazine dioxide -N-methane diphosphonic acid p- (1,4-thiazine dioxide) -N-phenylene-hydroxymethane diphosphonic acid α- (1,4-thiazine dioxide) -N-ethane -α, α-diphosphonic acid

3- (1, 4-thiazine dioxide) -N-1-hydroxypropane-1, 1-diphosphonic acid

6- (1, 4-thiazine dioxide) -N-1-hydroxyhexane -1,1-diphosphonic acid

11- (1,4-thiazine dioxide) -N- 1-hydroxyundecane -1,1-diphosphonic acid

Phosphonomethanesulfonic acid, trisodium salt trihydrate

Bis (methylenephosphono) aminoethanesulfonic acid

Tris (methylenephosphono) acetamido aminoethanesulfonic acid

Azacyclopentane -2,2- diphosphonic acid

N-methyl azacyclopentane -2,2-diphosphonic acid

N-decylazacyclopentane -2,2-diphosphonic acid N-tetradecylazacyclopentane -2,2-diphosphonic acid

Azacyclohexane -2,2- diphosphonic acid

1 - (4,5-Dihydro -3H-pyrrol-2-yl -) - pyrrolidinylidene -2,2-diphosphonic acid

Hydroxymethane diphosphonic acid, disodium salt

1 -Oxaethane -1, 2-diphosphonic acid undecane hydrate, tetrasodium salt

1-hydroxypropane -1, 1-diphosphonic acid

1-hydroxypropane -1,1- diphosphonic acid, tetrasodium salt

1-Hydroxybutane -1,1- diphosphonic acid heptadecane hydrate

1-hydroxybutane -1, 1-diphosphonic acid, trisodium salt

1-hydroxypentane -1, 1-diphosphonic acid, tetrasodium salt

1-hydroxyoctane -1, 1-diphosphonic acid, tetrasodium salt, cyclic tetraphosphonic acid, tetrasodium salt

Hexamethyl ester of cyclic tetraphosphonic acid

Hexamethyl ester of cyclic tetraphosphonic acid cyclic HEDP tetradecahydrate, hexasodium salt,

Those representatives of this class of substances which contain at least one phosphonic acid group and at least one polar functional group are preferably used.

The compositions according to the invention may contain, as further additives, conductivity pigments or conductive fillers, such as iron phosphide (Ferrophos), vanadium carbide, titanium nitride, carbon black, graphite, molybdenum disulfide or barium sulfate doped with tin or antimony. Iron phosphide is particularly preferred. The conductivity pigments or fillers are added to improve the weldability or to improve the coating with electrocoat materials. In addition, silica suspensions can be used - especially when using the anti-corrosion agents for aluminum substrates. These inorganic auxiliaries should be in finely divided form, that is to say their average particle diameter is between 0.005 and 5 μm, preferably between 0.05 and 2.5 μm. The auxiliaries are used in proportions between 0.1 and 30% by weight. Furthermore, the compositions may contain additives to improve the forming behavior, for example wax-based derivatives based on natural or synthetic waxes, for example polyethylene, polytetrafluoroethylene (PTFE) waxes or wax derivatives.

The pH of the application solutions - i.e. the original composition or a variant further diluted with water - is between 0.5 and 4.0, preferably between 0.7 and 2.5. When used in particular on metal strip surfaces, the application solution is applied in a manner known per se by roller application (chem coating), stripping, dipping / squeezing or spraying / squeezing onto a steel strip or (alloyed) aluminum strip, which may have a metallic coating. They are used at temperatures between 10 and 50 ° C, preferably between 15 and 35 ° C. The temperature can be adjusted by supplying heat via the workpiece or the treatment solution. Subsequently, the formation of a film and the crosslinking of this film as well as the anchoring on the metallic surface take place at the same time by means of suitable heat supply. For this purpose, peak metal temperatures (PMT) of 50 to 150 ° C. can be reached for a period of time between 1 and 120 seconds, preferably between 1 and 30 seconds. The basis weight of the coating after drying is 0.1 to 5, preferably 0.5 to 3 g / m ² and most preferably 0.8 to 2 g / m ^2. The mass per unit area that can be achieved in this way can be varied within wide limits, but it is significantly higher than was achievable according to the prior art.

The layers produced in this way can be coated with the paint systems customary in the household appliance and / or architecture industry, i.e. a liquid primer with subsequent coating with a liquid topcoat can be used, and powder coating with a single-layer paint can also be carried out . Furthermore, the corrosion protection layer according to the invention can be used immediately, that is without Primer treatment, to be coated with typical tape top coats. The layers created in this way protect the sheet and provide adequate protection against corrosion. For example, when coating (alloy) galvanized steel, a salt spray test in accordance with DIN 50021 SS can withstand more than 250 hours. A salt spray test of more than 250 hours according to DIN 50021 ESS has also been successfully passed for (alloyed) aluminum. A climatic test according to DIN 50017 KK for (alloy) galvanized steel is passed more than 3 weeks without white rust formation. The corrosion resistance of materials which have been treated with the corrosion protection composition according to the invention, with or without a primer coating, reaches the values which can be achieved with a conventional treatment. The reshaping behavior is improved compared to substrates not coated according to the invention; furthermore, the substrates coated according to the invention can be cataphoretically coated under the same conditions and with the same result as the material that is typically phosphated in automobiles. The method according to the invention can also take the place of conventional chromating and phosphating methods if subsequently a coating with a further corrosion protection layer such as Granocoat ™ and the like is to take place.

If the treatment according to the invention is carried out immediately after metallic surface finishing, for example electrolytic galvanizing or hot-dip galvanizing of steel strips, the strips can be brought into contact with the treatment solution or dispersion according to the invention without prior cleaning. However, if the metal strips to be treated were stored and / or transported before the coating according to the invention, they are usually provided with anti-corrosion oils or at least so far soiled that cleaning before the coating according to the invention is necessary. This can be done with common weakly to strongly alkaline cleaners, with aluminum and its alloys also with acidic cleaners. When used on aluminum and aluminum alloys, the corrosion protection composition according to the invention may also contain very low concentrations of organophosphonic acid and may be free of organophosphonic acids.

The invention will be explained in more detail below with the aid of a few exemplary embodiments. In the case of the compositions, all amounts are parts by weight, unless stated otherwise.

The individual components listed in Table 1 are usually mixed in the order mentioned at room temperature.

H 3800

Table 1

Example 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Demineralized water 73.5 62.4 50.6 74.6 75.8 53.0 53.6 62.0 52.6 62.0 52.7 53.2 52.6 52.0 74.5

H ₃ P0 ₄ (75%) 3.5 3.5 2.4 - - 6.3 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5

H ₂ TiF ₆ (50%) ¹ > 5.0 5.0 5.0 1.8 1.4 4.5 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 1.8 modified polyvinylphenol 2.) 5.0 5.0 3.6 2.6 2.0 3.2 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 2.6

MnC0 ₃ - 2.1 2.1 - - -

Si0 ₂ ³⁾ - - - 0.7 0.6 0.7 basic Zr carbonate - - - 0.3 0.2 - 0.3

(Meth) acrylate copolymer '- - - 20.0 20.0 - - 20.0

(Meth) acrylate copolymer ⁵⁾ 13.0 22.0 36.3 30.4 30.0 18.0 28.0 18.0 28.0 28.0 28.0 33.0

Wax emulsion ⁶ '2.6 2.9 2.9 2.9 2.9 2.9 2.9 2.9 -

Organophosphonic acids ⁷ '1-aminopropane-1, 1 -diphosphonic acid 3.6 aminotrimethylenephosphonic acid 3.0 1-hydroxiethan-1, 1 -diphosphonic acid 3.6 0.1 2-hydroxiphosphonoacetic acid 2.9 oligomaleeinphosphonic acid 2.4 phosphinoacrylic acid 3.0 2- Phosphonobutane-1,2,4-tricarboxylic acid. - - - - - - - - - - 1.5 - pH 1.5 1.4 1.2 1.8 2.0 1.3 1.5 1.2 1.3 1.2 1.2 1.2 1.1 1.5 1 ,8th

Corrosion protection ^8} niOniOniO 1.5 ^y) 1, 5 ⁹ 'niOniOiOiOiOiOiOiOiO 1, 5 ^a

H 3800

Continuation of table 1

1. Similar results are obtained with H2SiF6 and H2ZrF6

2. Poly- (5-vinyl-2-hydroxibenzyl) -N-methylglucamine, approx. 30% solids

3. Aqueous silica suspension, approx. 12% solids

4. (meth) acrylate copolymer from C1 to C4 esters of (meth) acrylic acid with N-alkylolacrylamide groups, approx. 46.5% solids, viscosity 36 mPas / 25 ° C, MFT 15 ° C

5. Self-crosslinking nonionic acrylic resin dispersion with N-alkylolacrylamide groups and free carboxyl groups, approx. 45.5% solids, viscosity 600 mPas / 25 ° C, Tg 33 ° C

6. Wax emulsion based on polyethylene and paraffins, approx. 40% solids

7. Other organophosphonic acids used were, for example: 1,2-diaminopropane tetrakis (methylenephosphonic acid), diethylenetriaminepentakis (methylenephosphonic acid),

Ethylenediamine tetrakis (methylenephosphonic acid), N-carboxy methane-1-aminoethane-1,1-diphosphonic acid 8.) Test according to DIN 50021 SS, white rust attack <5 area% after 100 h 9.) Additional coating with PUR / PA coil -Coating top coat, 20 μm, test according to DIN 50021 ESS, infiltration at the test scratch in mm

Examples 1 to 3 and 6 and 7 listed in Table 1 are not according to the invention, they already show significant white rust attack on galvanized steel in the test according to DIN 50021 SS after about 100 hours. Examples 4, 5 and 15 show good results of corrosion protection on aluminum, Examples 8 to 14 show good results of corrosion protection on galvanized steel.

Claims

claims

1.) Containing chromium-free aqueous corrosion protection agent for the one-step coating of metallic substrates

a.) 0.5 to 100 g / l hexafluoro anions of titanium (IV) silicon (IV) and / or zircon (IV)

b.) 0 to 100 g / l phosphoric acid

c.) 0 to 100 g / l of one or more compounds of cobalt, nickel, vanadium, iron, manganese, molybdenum or tungsten.

d.) 0.5 to 30% by weight of at least one water-soluble or water-dispersible film-forming organic polymer or copolymer,

e.) 0.1 to 10% by weight of an organophosphonic acid

f.) any other auxiliaries and additives.

2.) Corrosion protection agent according to claim 1, characterized in that the at least one film-forming (co) polymer is selected from epoxy resins, styrene copolymers, butadiene copolymers, polyurethanes, melamine resins, (meth) acrylate polymers or mixtures thereof.

3.) Corrosion protection agent according to claim 2, characterized in that at least one film-forming (co) polymer contains crosslinkable functional groups.

4.) Corrosion protection agent according to claim 3, characterized in that it additionally contains a crosslinking agent.

5.) Corrosion protection agent according to at least one of the preceding claims, characterized in that it contains 0.1 to 30% by weight of a conductivity pigment and / or another inorganic auxiliary as a further additive.

6.) Corrosion protection agent according to claim 5, characterized in that the conductivity pigment is selected from carbon black, graphite, molybdenum disulfide, doped barium sulfate, iron phosphide, vanadium carbide, titanium nitride.

7.) Corrosion protection agent according to claim 5 or 6, characterized in that the conductivity pigment or the further inorganic auxiliary has an average particle diameter of 0.005 - 5 microns, preferably 0.05 to 2.5 microns.

8.) Corrosion protection agent according to at least one of the preceding claims, characterized in that it is a further additive forming aid based on natural or synthetic waxes, e.g. Contain polyethylene, polytetrafluoroethylene waxes and / or waxes or wax derivatives.

9.) Corrosion protection agent according to at least one of the preceding claims, characterized in that it has a pH in the range from 0.5 to 4.0, preferably from 0.7 to 2.5.

10.) Process for the corrosion-protecting treatment of (possibly metallic coated) steel or aluminum or its alloys, characterized in that a.) The surface of the metal for a period of time between 0.5 and 60 seconds with an anti-corrosion agent according to at least one of the preceding

Claims are brought into contact. b.) the excess anti-corrosion agent is possibly removed from the surface and c.) the treated substrate is heated to peak metal temperatures between 50.degree. C. and 150.degree. C. within a period of 1 to 120 seconds by suitable supply of heat, crosslinking of the polymeric film and its anchoring taking place at the same time on the metal surface.

11.) Method according to claim 10, characterized in that the metallic coating of the steel is selected from hot-dip galvanizing, alloy galvanizing, electrolytic galvanizing, copper plating, nickel plating or aluminizing.

12.) Method according to claim 10 or 11, characterized in that the corrosion protection agent is applied to the workpiece surface by flooding / squeezing, spraying / squeezing, suitable scrapers or roller applications.

13) Steel or aluminum strip coated by a method according to claim 10 to 12, characterized by a mass per unit area of the layer between 0.1 and 5, preferably between 0.5 and 2.0 g / m ² .

14.) Process for the corrosion-protective treatment of aluminum according to one of claims 10 to 13, characterized in that the anti-corrosion agent according to claim 1 to 9 contains no organophosphonic acid.

15.) Steel or aluminum strip coated by one of the methods according to one of claims 10 to 14, characterized in that the coating primer is omitted when coating in the coil coating process.