AU5065600A - Chromium-free anticorrosive and anticorrosive method - Google Patents

Description

WO 00/71626 PuT/E5i.UU/ U I40I 1 "A chromium-free anti-corrosive agent and an anti-corrosive process" The present invention relates to a chromium-free organic/inorganic anti-corrosive agent and an anti corrosive process for treating surfaces of steel, which are optionally provided with a metallic coating of zinc, 5 aluminum, copper, nickel, etc., or of aluminum and its alloys. It is particularly suitable for surface treatment in strip plants (coil-coating) for applying this substrate in the domestic and architectural areas and in the automobile industry. 10 For the temporary corrosion protection of galvanized or alloy-galvanized steel strips, these are often either simply rubbed with oil or, in the event that more intense corrosive stresses are expected, phosphatized or 15 chromatized. Before receiving a final coating of organic binders (primer, lacquers, electrodeposited lacquers), a multi-stage process is generally performed. When using galvanized metal strips or aluminum and its alloys in the domestic appliance or architectural industries, optionally 20 after previous removal of the oil layer, the metal surface is first provided with an anti-corrosive layer. The best method for anti-corrosive treatment known from the prior art is chromatizing in which the metal surface is coated with a chromium(III) and/or chromium(VI)-containing layer, 25 generally at a rate of about 5 to 15 mg/m 2 of chromium. Phosphatizing, as an alternative measure for temporary anti-corrosive treatment, has two kinds of disadvantages. On the one hand the appearance of the metal surface may be altered in an undesirable manner. On the other hand, 30 phosphatizing is a procedure which is very costly in terms of the equipment required because, depending on the WO 00/71626 PCT/E1fUU/U1407 2 substrate material, an additional activation stage and, generally after phosphatizing, a passivating stage is required. Over and above the actual anti-corrosive effect, inorganic coating ensures good adhesion of the primer which 5 is applied thereto. There again, the primer not only has a beneficial effect on the anti-corrosive effect of the inorganic conversion layer, the primer layer in its turn also provides a good adherent substrate for the topcoat lacquer. 10 To an increasing extent, metal strip producers are supplying sheet metal with a functional preliminary coating which facilitates mechanical processing such as punching, drilling, bending, shaping and/or deep drawing. Only after 15 final assembly of the workpiece is this finally provided with a topcoat lacquer. Functional precoating must provide the sheet metal not only with corrosion-inhibiting properties but also properties which facilitate mechanical processing. In order to produce these layers, processes 20 based on chromium-containing inorganic/organic compositions and also chromium-free, exclusively organic preparations are known, wherein the latter have only a limited anti corrosive effect. 25 In the automobile industry, galvanized steel sheeting which has been precoated with thin organic films is being used to an increasing extent. This substrate ensures a good anti corrosive effect, to be precise even in the bodywork sector, which cannot be achieved in a conventional 30 lacquering process, or only with difficulty. The use of these types of precoated materials enables cost-intensive secondary anti-corrosive measures such as cavity sealing and joint sealing to be reduced or even avoided altogether. To facilitate the subsequent processing steps such as spot 35 welding or electrodeposition lacquering, the organic films frequently also contain pigments and fillers which increase the electrical conductivity. These types of materials are WO 00/71626 VUTI$/Zr±UU/U'24O/ 3 known, for example, under the names Durasteel", Bonazinc', Durazinc" or Granocoat". Materials coated in this way have, for example, on top of a conversion layer which is a chromatizing or phosphatizing layer, a thin organic coating 5 which consists, for example, of binder based on epoxide or polyurethane resins, polyamides or polyacrylates. The organic layers are generally applied with a thickness of about 0.3 to about 5 pm. These coatings on metal strips are generally produced in a two-stage process which is costly 10 in terms of equipment, in which first the inorganic conversion layer is produced and then the organic polymer film is applied in a second treatment stage. It is known that attempts have already been made to use 15 single stage coating processes in which the inorganic conversion treatment and 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 20 galvanized steel in which the substrate is brought into contact with a treatment solution with the following composition: 0.1 to 10 g/l of a tetrafluoro or hexafluoro acid of boron, silicon, titanium and zirconium or hydrofluoric acid, about 0.015 to about 6 g/l of cations of 25 cobalt, copper, iron, manganese, nickel, strontium or zinc and optionally up to about 3 g/l of a polymer chosen from polyacrylic acid, polymethacrylic acid and their esters. The pH of this treatment solution is within the range from about 4 to about 5. 30 WO 95/14117 also describes a process for treating surfaces of zinc or aluminum or their alloys. In this case, the surfaces are brought into contact with a treatment solution with a pH of less than 3 which contains a complex between a 35 metal oxoion and a heteroion. The metal oxoion is chosen from molybdate, tungstate and vanadate. The heteroion is chosen from phosphorus, aluminum, silicon, manganese, WO 00/71626 YUrX/Mruu/ u'Zo 4 magnesium, zirconium, titanium, tin, cerium and nickel. Furthermore, the treatment solution also contains an organic film-producer which is compatible with the other components in the solution. Suitable film-producers may be, 5 for example, polyacrylates such as in particular polymers of methyl methacrylate, n-butyl acrylate, hydroxethyl acrylate and glycerinepropoxy triacrylate. EP-A-694 593 recommends the treatment of metal surfaces 10 with a treatment solution which contains the following components: an organic polymer or copolymer in which 0.5 to 8 % of the monomers contain groups which can form compounds with metal ions, complex cations or anions of aluminum, calcium, cerium, cobalt, molybdenum, silicon, vanadium, 15 zirconium, titanium, trivalent chromium and zinc, an oxidising agent such as nitric acid, perchloric acid or hydrogen peroxide and an acid such as, for example, oxalic acid, acetic acid, boric acid, phosphoric acid, sulfuric acid, nitric acid or hydrochloric acid. 20 WO 95/04619 discloses the treatment of metal surfaces with a treatment solution which contains at least the following components: fluoro complexes of titanium, zirconium, hafnium, silicon, aluminum and boron, metal ions chosen 25 from cobalt, magnesium, manganese, zinc, nickel, tin, copper, zirconium, iron and strontium, phosphates or phosphonates and also water-soluble or water-dispersible organic film-producers. 30 EP-A-792 922 describes a chromium-free corrosion inhibiting coating composition for aluminum or aluminum alloys which contains a film-producing organic polymer and (i) a salt chosen from esters of rare earth metals, alkali metal or alkaline earth metal vanadates and also (ii) a borate salt 35 of an alkaline earth metal. Epoxides including polyimide based epoxides, polyurethanes, acrylic polymers and alkyd based systems, for example, are mentioned as preferred WO 00//1626ba " 5 polymers. This coating composition thus has to contain, in addition to the organic film-producer, at least one borate and another component which may be a vanadate. 5 EP-A-685534 describes a process for protecting a steel substrate by means of a thin film of an organic/inorganic hybrid polymer based on an alkoxysilane, another condensable organometal compound of the formula M(OR) 4 and also (meth)acrylic acid and a polymerisation initiator. The 10 coating is produced by thermal polymerisation or photopolymerisation. Zirconium and titanium are mentioned as metals for the organometal compound. It is stated that a film of this type protects steel substrates against corrosion and oxidation; in addition the substrate is 15 intended to be protected by this coating against shock and other effects. WO 98/47631 describes a process for improving defective pretreated metal surfaces. For this, an aqueous acid 20 solution which contains fluorometalate anions, divalent or tetravalent cations of cobalt, magnesium, manganese, zinc, nickel, tin, copper, zirconium, iron and strontium, phosphorus-containing inorganic oxoanions and phosphonate anions and a water-soluble and/or water-dispersible organic 25 polymer and/or a polymer-producing resin is applied to the defective metal surface. The document provides no data about whether these types of compositions are also suitable for the first-time coating of non-precoated metal strips. 30 Still unpublished DE-A-1 9754108.9 describes a chromium free aqueous anti-corrosive agent for treating surfaces of galvanized or alloy galvanized steel and of aluminum. It contains, as essential components, hexafluoro anions of titanium and/or zirconium, vanadium ions, cobalt ions, 35 phosphoric acid and preferably also an organic film producer, in particular one based on polyacrylate. This WO 00/71626 PCT/EPOO/04267 6 anti-corrosive agent is particularly suitable for the anti corrosive treatment of metal strips. DE-A-4412138 describes a process for producing chromium 5 free conversion layers on the surface of aluminium and its alloys in a no-rinse process. That document discloses the treatment of surfaces with aqueous solutions which contain titanium and/or zirconium and an orthophosphate, fluorides and 0.15 to 1.5 g/l of a film-producer which is water 10 soluble or homogeneously dispersible in water. After drying these compositions, a solid film with a weight per unit area of about 50 to 350 mg/m 2 remains on the metal surface. Thicker layers, in particular those with a large proportion of organic film-producer, are not disclosed. 15 US-A-5449415 describes a chromium-free conversion coating specifically for cold-rolled steel which contains one component consisting of titanium, zirconium, hafnium, silicon and boron anions as well as a cation component 20 consisting of cobalt, magnesium, manganese and similar heavy metals and an amount of free acid sufficient to ensure the pH is in the range between 0.5 and 5.0. Furthermore, these compositions contain inorganic phosphorus-containing oxyanions or phosphonate anions and a 25 small proportion of water-soluble or water-dispersible organic polymers and polymer-forming resins. The ratio of polymers or polymer-forming resins to inorganic anions in the coating should be in the range 1:2 to 3:1. Coating thicknesses between 5 and 500 mg/m 2 (weight per unit of 30 surface area of the dry film) can be produced with these. Thicker films cannot be produced with these coating compositions. US-A-5427632 describes very similar compositions to those 35 in the previously mentioned document, with the difference that they also contain a dissolved oxidising agent and anti-settling agents. Thicker layers of coating are not WO 00/71626 PCT/EPO0/04267 7 disclosed here either, according to the disclosure in this document. DE-A-19654642 describes aqueous solutions for treating 5 metallic surfaces and processes for their use. This aqueous solution should contain one or more compounds of the type XYZ, wherein Y is an organic group with up to 50 carbon atoms and X is a carboxylic acid, sulfone, sulfate, phosphonate or phosphate group and Z is a functional group 10 such as e.g. the OH-, SH- NH 2 - or CN- group. These types of compounds are also called SAM compounds (self assembling molecule). They enable only very thin layers of coatings, virtually in the monomolecular range; that is to say layer thicknesses of 5 to 10 nm are typically achieved with 15 these. Despite this extensive prior art, there is still a need for improved coating processes for metal surfaces in which an inorganic passivating layer and also a thin organic polymer 20 layer can be applied to the metal surfaces in the same treatment step. Here, thin organic polymer layers are understood to be much thicker layers than those disclosed in the prior art. Nevertheless, the coating is intended to facilitate and even to make easier the punching out and 25 reshaping of structural parts made from the coated metal strips. Furthermore, the layers on the metal substrate should withstand further manufacturing steps up to assembling the products, such as for example cleaning, optionally phosphatizing, riveting or welding and either be 30 directly overpaintable with a topcoat lacquer or be coatable by electrodeposition lacquering. For protection of the environment and health and safety at work reasons, the treatment process should be performable without the use of chromium compounds and if possible also with the exclusion 35 of organic solvents. The main fields of application are the initially mentioned domestic appliance and architectural industries and also the automobile industry.

WO 00/71626 PCr/SYUU/U'ZO I 8 This object is achieved, according to the invention, as stated in the claims. It consists substantially in the provision of a chromium-free anti-corrosive agent containing water and 5 a) 0.5 to 100 g/l of hexafluoro anions of titanium(IV), silicon(IV) and/or zirconium(IV), b) 0 to 100 g/l of phosphoric acid, c) 0 to 100 g/l of one or more compounds of cobalt, 10 nickel, vanadium, iron, manganese, molybdenum or tungsten, d) 0.5 to 30 wt.% of at least one water-soluble or water dispersible film-producing organic polymer or copolymer (with respect to active substance), 15 e) 0.1 to 10 wt.% of an organophosphonic acid, f) optionally further auxiliary substances and additives. The invention also provides a process for the anti corrosive treatment of steel which is optionally provided 20 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 placed in contact with 25 an anti-corrosive agent of the type mentioned above for a period between 0.5 and 60 seconds at a treatment temperature between 10 and 50 0 C, preferably 15 and 35 0 C; the treatment temperature may be adjusted by supplying heat via the workpiece or the treatment 30 solution, b) excess anti-corrosive agent is optionally removed from the surface and c) the item is heated for a period from 1 to 120 seconds, by an appropriate heat supply, wherein peak metal 35 temperatures between 50 0 C and 150 0 C should be reached, wherein cross-linking of the polymer film and the WO 00/71626 e-J4.r.ruu/ u-2o 9 anchoring thereof to the metal surface takes place at the same time. In a preferred manner, the anti-corrosive agent is applied 5 to the workpiece surface, preferably metal strip surface, by flooding/squeezing, spraying/squeezing or by an appropriate wiper or roller method of application. The preferred concentration ranges for components a) to e) 10 in the anti-corrosive agent are: a) 5-50 g/l of hexafluoro anions of titanium(IV), silicon(IV) and/or zirconium(IV), b) 0-50 g/l of phosphoric acid, c) 0-40 g/l of ions of cobalt, nickel, vanadium, iron, 15 manganese, molybdenum, tungsten, d) 5-30 wt.% of one or more film-producing organic polymers or copolymers (with respect to active substance), e) 0.1-10 wt.% of an organophosphonic acid. 20 The previously mentioned concentration ranges for components a) to e) should be chosen in such a way that the ratio of polymer component d) to inorganic anion component a) is greater than 3.1. This is enabled in "thick layers", 25 wherein the greater proportion of the layer produced is the organic polymer. "Thick layers" in the context of this invention have weights per unit of surface area of coating after drying between 0.1 and 5 g/m 2 . 30 The pH of the anti-corrosive agent is within the range 0.5 to 4.0, preferably within the range 0.7 to 2.5. An acid agent of this type partly dissolves the metal surface being treated so that a treatment bath which has already been in use for some time may contain additional cations which 35 arise from treated metal substrates. Examples of these are zinc, aluminum, iron, nickel, silicon, lead and copper.

WO 00/71626 FUT/EFUU/U'zI 10 A person skilled in the art is familiar with the fact that the previously mentioned components, in particular the inorganic compounds, can enter into reactions with each other so that they are present in the treatment solution in 5 the form which is stable under the conditions mentioned for pH. As an example, some of the hexafluoro anions are present in the form of the free acid. Numerous compounds are suitable for use as film-forming 10 organic polymers or copolymers, but they must satisfy two essential selection criteria. On the one hand they must be soluble or dispersible in sufficient concentration in the strongly acid aqueous solution, which also contains polyvalvent inorganic ions, without this leading to 15 coagulation and/or precipitation of the polymer constituents. On the other hand, they must contain at least some cross-linkable groups which enable the polymer layer to cross-link sufficiently well within a short time as a result of the supply of heat and to adhere to the 20 substrate. Concrete examples of film-producing polymers are epoxide resins, aminoplastic resins (e.g. melamine/formaldehyde resins, urea/formaldehyde resins), tannins, phenol/ 25 formaldehyde resins, polymers of vinylphenol with sufficient alkyl or substituted alkyl-aminomethyl groups in the phenolic ring to ensure the water-solubility or water dispersibility of the polymer. Other examples are water soluble or water-dispersible polyurethane polymers, 30 acrylate homopolymer and in particular copolymer dispersions, methacrylate homopolymer and/or copolymer dispersions and butadiene copolymer dispersions or styrene copolymer dispersions. In particular, the copolymers based on olefinically unsaturated monomers may contain cross 35 linkable comonomers known per se. The following may be mentioned by way of example: acrylic acid, methacrylic acid, glycidyl-(meth)acrylate, acrylamide, N-methylol- WO 00/71626 ''./" n /v '" 11 acrylamide, N,N-bis-alkoxymethyl (meth)acrylamide and similar thermally cross-linkable groups, wherein the alkoxy groups may contain 1 to 4 carbon atoms. Furthermore, cross linking agents known per se may be used in the form of 5 epoxide resins, urea derivatives or (blocked) polyisocyanates or oligomeric derivatives thereof. Self cross-linking or externally cross-linkable (meth)acrylate dispersions or emulsions or combinations of these with epoxide resins and/or copolymers of 4-hydroxystyrene are 10 particularly preferred. The last-mentioned copolymers may be represented by the following general formula: y-(R'-N-R 2 aminomethyl)-4-hydroxy-styrene, wherein y is 2, 3, 5 or 6 and R' is an alkyl group with 1 to 4 carbon atoms, preferably a methyl group and R 2 can be represented by the 15 following general formula: H(CHOH),CH 2 -, wherein n is an integer between 1 and 7, preferably between 3 and 5. The average molecular weight of the previously mentioned polymers is normally in the range between 600 and 20,000, preferably between 800 and 6,000. The molecular weights of 20 water-soluble polymers are more likely to be found in the lower range, while the molecular weights of the water dispersible polymers are generally found in the middle to upper range. Further suitable film-producing organic (co)polymers are mentioned in T. Brock, M. Groteklaes, P. 25 Miscke, "Lehrbuch der Lacktechnologie", Vincentz-Verlag, 1998 in section 2.1.4 or section 3.5. The binders mentioned there are express constituents of this application. Another important constituent of the compositions are 30 organophosphonic acids, concrete examples being the following phosphonic acids and diphosphonic acids: 1-hydroxy-l-phenylmethane-1,1-diphosphonic acid 35 1-hydroxy-l-phenylmethane-1,1-diphosphonic acid.2H 2 0 p-hydroxyphenyl-1-aminomethane-1,1-diphosphonic acid p-hydroxyphenyl-l-hydroxymethane-1,1-diphosphonic acid.H 2 0 WO 00/71626 L .iv,' urme 12 1-hydroxy-1-phenylmethane-1,1-diphosphonic acid.H 2 0,Na 2 salt 1-hydroxyphenylmethane-1,1-diphosphonic acid.H 2 0 1-amino-i-phenylmethane-1,1-diphosphonic acid 4-aminophenyl-l-hydroxymethane-1,1-diphosphonic acid.H 2 0 5 p-aminophenyl-1-aminomethane-1,1-diphosphonic acid p-chlorophenylmethane-1,1-diphosphonic acid 1-chloro-1-phenylmethane-1,1-diphosphonic acid.2H 2 0 p-chlorophenyl-1-hydroxymethane-1,1-diphosphonic acid.2H 2 0 1-chlorophenylmethane-1,1-diphosphonic acid.H 2 0 10 p-chlorophenyl-1-chloromethane-1,1-diphosphonic acid 4-chlorophenyl-1-chloromethane diphosphonic acid.2H 2 0 p-hydroxyphenylaminomethylene diphosphonic acid, Na 2 salt p-hydroxyphenyl-1-aminomethane-1,1-diphosphonic acid, containing methylol 15 3,4-dimethylphenyl-1-chloromethane diphosphonic acid 3,4-dimethylphenyl-1-hydroxymethane diphosphonic acid 3,4-dimethylphenylaminomethane diphosphonic acid 3,4-dimethylphenyl-1-chloromethane-1,1-diphosphonic acid.2H 2 0 20 4-dimethylaminophenyl-1-hydroxymethane diphosphonic acid 4-(N-benzyl-N,N-dimethylamino)-phenyl-1-hydroxymethane diphosphonic acid 4-trimethylaminophenyl-1-hydroxymethane diphosphonic acid 3,4,5-trimethoxyphenyl-1-aminomethane-1,1-diphosphonic acid 25 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 30 1-amino-1-cyclohexylmethane-1,1-diphosphonic acid 1-hydroxy-1-cyclohexylmethane-1,1-diphosphonic acid, Na salt 1-hydroxy-1-cyclohexylmethane-1,1-diphosphonic acid, Na 3 salt 35 [4-(aminomethyl)-cyclohexyll-l-hydroxymethane-1,1 diphosphonic acid 4-methoxybenzoylacetonitrile, phosphonylated WO 00/71626 JFL/E'uu/uwoI 13 N-(hydroxymethyl)-1-aminoethane-1,1-diphosphonic acid 1,3-diaminopropane-1,1-diphosphonic acid 3-dimethylamino-1-aminopropane-1,1-diphosphonic acid 3-monomethylamino-1-aminopropane-1,1-diphosphonic acid 5 3-(N-dodecylamino)-i-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) 10 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 15 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 20 1,3-dihydroxy-3-phenylpropane-1,1-diphosphonic acid 3-N,N-dimethylaminopropionic acid.HCl 3-dimethylamino-1-hydroxypropane-1,1-diphosphonic acid, Na salt 1,3-dihydroxypropane-1,1-diphosphonic acid, Na 2 salt 25 1-hydroxy-3-diethylaminopropane-1,1-diphosphonic acid, Na salt 1,3-dihydroxy-3-phenylpropane-1,1-diphosphonic acid, Na2 salt 1,3-diaminobutane-1,1-diphosphonic acid 30 1-hydroxy-3-aminobutane-1,1-diphosphonic acid 3-monoethylamino-l-aminobutane-1,1-diphosphonic acid 4-amino-l-hydroxybutane-1,1-diphosphonic acid 4-N,N-dimethylamino-l-hydroxybutane-1,1-diphosphonic acid 6-amino-l-hydroxyhexane-1,1-diphosphonic acid 35 1,6-dihydroxyhexane-1,1-diphosphonic acid 1,6-dihydroxyhexane-1,1-diphosphonic acid, Na 2 salt 1,11-dihydroxyundecane-1,1-diphosphonic acid WO 00/71626 rka±/ ruu/ uaU'I 14 ii-amino-1-hydroxyundecane-1,1-diphosphonic acid n-propylphosphonic acid butyl-1-phosphonic acid hexyl-1-phosphonic acid 5 octyl-1-phosphonic acid decane-1-phosphonic acid dodecyl-1-phosphonic acid tetradecyl-1-phosphonic acid octadecyl-1-phosphonic acid 10 octadecane monophosphonic acid, Na salt eicosane monophosphonic acid, Na salt t-1,2-diaminocyclohexane-tetrakis(methylenephosphonic acid) glucamine-bis(methylenephosphonic acid) glucamine-bis(methylenephosphonic acid), Na salt 15 1-ureidoethane-1,1-diphosphonic acid methylenephosphonylated uramil pyrimidyl-2-aminomethane diphosphonic acid pyridyl-2-aminomethylene diphosphonic acid N,N'-dimethylureidomethane diphosphonic acid 20 N-(2-hydroxyethyl)ethylenediamine-N,N',N'-trismethylene phosphonic acid N-(2-hydroxyethyl)ethylenediamine-N,N'N'-trismethylene phosphonic acid.H 2 0 aminoacetic acid-N,N-dimethylenephosphonic acid 25 1,2-diaminopropane-tetrakis(methylenephosphonic acid) 2-hydroxypropane-1,3-diamine-tetrakis(methylenephosphonic acid) 5-hydroxy-3-oxa-l-aminopentane-bis(methylenephosphonic acid) 30 imino-bis(methylenephosphonic acid) nitrosamine of imino-bis(methylenephosphonic acid) nitrosamine of imino-bis(methylenephosphonic acid), Na 2 salt y,y-diphosphono-N-methylbutyrolactam amidinomethylene diphosphonic acid 35 formylaminomethane diphosphonic acid 2-iminopiperidone-6,6-diphosphonic acid.H 2 0 2-iminopyrrolidone-5,5-diphosponic acid WO UU/IL62 ""I' 15 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 5 acid 1,2-dihydroxypropane-3-amino-bis(methylenephosphonic acid) 2-hydroxypropane-1,3-diamine-tetrakis(methylenephosphonic acid) 3,6-dioxa-1,8-diaminooctane-tetrakis(methylenephosphonic 10 acid) 1,5-diaminopentane-tetrakis(methylenephosphonic acid) methylamino-dimethylenephosphonic acid N-hexylamino-dimethylenephosphonic acid decyclamino-dimethylenephosphonic acid 15 3-picolylaminodimethylenephosphonic acid.H 2 0 methanephosphonic acid methanediphosphonic acid methanediphosphonic acid.H23, Na2 salt dichloromethanediphosphonic acid.5H 2 0, Na 2 salt 20 tetraisopropyl dichloromethanediphosphonate 1,1-diphosphonethane-2-carboxylic acid ethane-1,1-diphosphonic acid ethane-1, 1-diphosphonic acid, Na, salt ethane-1,2-diphosphonic acid 25 ethane-1,1,2-triphosphonic acid ethylenediphosphonic acid, Na 4 salt 1,2-diphosphonoethane-1,2-dicarboxylic acid 1,2-diphosphonoethane-1,2-dicarboxylic acid.2H 2 0 ethane-1,1,2,2-tetraphosphonic acid.H 2 0, hexaguanidine salt 30 ethane-1,1,2,2-tetraphosphonic acid, hexaguanidine salt ethane-1,1,2,2-tetraphosphonic acid, guanidine salt 1-phosphonoethane-1,2,2-tricaroxylic acid, K salt phosphonoacetic acid a-chloro-a-phosphonoacetic acid 35 a-phosphonoacetic acid 1-phosphonopropane-2,3-dicarboxylic acid 1-phosphonopropane-1,2,3-tricarboxylic acid, Na 5 salt WO 00/71626 et/5"UU/ze 40' 16 1-phosphonopropane-1,2,3-tricarboxylic acid.H 2 0 propane-1,1,3,3-tetraphosphonic acid, Na 6 salt aminomethane diphosphonic acid dimethylaminomethane diphosphonic acid 5 N-decylaminomethane-1,1-diphosphonic acid N-decylaminomethane diphosphonic acid N,N-dimethylaminomethanediphosphonic acid monohydrate dimethylaminomethane diphosphonic acid, Na 2 salt N-decylaminomethane diphosphonic acid, Na, salt 10 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 15 1-aminopropane-1,1-diphosphonic acid 1-aminopropane-l,1,3-triphosphonic acid 1-aminobutane-1,1-diphosphonic acid 1-aminohexane-1,1-diphosphonic acid 1-aminodecane-1,1-diphosphonic acid 20 1-aminohexadecane-1,1-diphosphonic acid 1-isononanoylamido-1,1-dimethylenemethane phosphonic acid stearic acid amido-1,1-dimethylenemethane phosphonic acid coco fatty acid amido-1,1-dimethylenemethane phosphonic acid 25 isononanoic acid amido-1,1-diethylmethane phosphonic acid 1-aminohexyl-1-phosphonic acid 1-aminooctyl-1-phosphonic acid 1-hydroxyoctyl-1-phosphonic acid 1-hydroxydecyl-1-phosphonic acid 30 1-aminodecyl-1-phosphonic acid 1-hydroxydecyl/dodecyl-1-phosphonic acid 1-hydroxy-1-dodecyl-1-phosphonic acid 1-hydroxydodecane-1-phosphonic acid 1-hydroxy-3,6,9-trioxadecane-1,1-diphosphonic acid, Na 3 salt 35 12-hydroxy-12-phosphonostearic acid, Na salt cocosalkylaminobis(methylenephosphonic acid) phosphonylated polyglycol diacid WO 00/71626 PCT/EPUU/U426/ 17 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 5 1-hydroxy-3-oxo-4-ethyl-4-methylhexane-1,1-diphosphonic acid.H 2 0, 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, Na salt 10 1-amino-3-oxo-4,4-dimethylheptane-1,1-diphosphonic acid 1-hydroxy-3-oxo-4,4-dimethylheptane-1,1-diphosphonic acid.H 2 0, Na salt 4,4-dimethyl-3-oxo-hept-l-ene-1,1-diphosphonic acid 4,4-dimethyl-3-oxo-hept-1-ene-1,1-diphosphonic acid, Na 15 salt 1-amino-3-oxo-4,4-dimethyldecane-1,1-diphosphonic acid aminomethane monophosphonic acid toluylaminomethane phosphinic acid p-hydroxyphenyl-1-aminomethanephosphonic acid 20 semihydrochloride N-ethylamino-(phenylmethanediphosphonic acid) 1-benzylamino-1-phenylmethane-1-phosphonic acid 1-hydroxyethane monophosphonic acid 1-hydroxyethane-1-monophosphonic acid, Na 2 salt 25 1-hydroxyethane-1,1-diphosphonic acid (HEDP) 2-[benzimidazolyl-(2,2)-]-ethane diphosphonic acid monohydrate 2-[benzimidazolyl-(2,2)-]-ethane diphosphonic acid N-carboxymethane--aminoethane-1,1-diphosphonic acid 30 1,5-diaminopentane-1,1,5,5-tetraphosphonic acid, trihydrate a-octadecyl-phosphonosuccinic acid a-N-dodecylaminobenzylphosphonic acid 0-trifluoromethyl-0-phosphonobutyric acid 1-decylpyrrolidone-2,2-diphosphonic acid 35 pyrrolidone-5,5-diphosphonic acid 2, 2-diphosphono-N-decylpyrrolidone ',y-diphosphono-N-methylbutyrolactam WO 00/71626 Z"/nr±uu/ uI 'o , 18 benzene phosphonous acid 1,4-thiazine dioxide-N-methane diphosphonic acid p-(1,4-thiazine dioxide)-N-phenylene-hydroxymethane diphosphonic acid 5 a-(1,4-thiazine dioxide)-N-ethane-a,a-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 10 11-(1,4-thiazine dioxide)-N-1-hydroxyundecane-1,1 diphosphonic acid phosphonomethanesulfonic acid, Na 3 salt trihydrate bis(methylenephosphono)aminoethanesulfonic acid tris(methylenephosphono)-acetamido-aminoethanesulfonic acid 15 azacyclopentane-2,2-diphosphonic acid N-methylazacyclopentane-2,2-diphosphonic acid N-decylazacyclopentane-2,2-diphosphonic acid N-tetradecylazacyclopentane-2,2-diphosphonic acid azacyclohexane-2,2-diphosphonic acid 20 1-(4,5-dihydro-3H-pyrrole-2-yl)-pyrrolidinylidene-2,2 diphosphonic acid hydroxymethane diphosphonic acid, Na 2 salt 1-oxaethane-1,2-diphosphonic acid undecanehydrate, Na, salt 1-hydroxypropane-1,1-diphosphonic acid 25 1-hydroxypropane-1,1-diphosphonic acid, Na, salt 1-hydroxybutane-1,1-diphosphonic acid heptadecanehydrate 1-hydroxybutane-1,1-diphosphonic acid, Na 3 salt 1-hydroxypentane-1,1-diphosphonic acid, Na, salt 1-hydroxyoctane-1,1-diphosphonic acid, Na, salt 30 cyclic tetraphosphonic acid, Na 4 salt hexamethyl ester of cyclic tetraphosphonic acid hexamethyl ester of cyclic tetraphosphonic acid cyclic HEDP tetradecahydrate, Na 6 salt 35 In a preferred way, those representatives of this class of substances are used which contain at least one phosphonic acid group and at least one polar functional group.

WO 00/71626 G/r~iuu/ U-tazO 19 As further additives, compositions according to the invention may contain conductivity pigments or conductive fillers such as e.g. iron phosphide (Ferrophos), vanadium carbide, titanium nitride, carbon black, graphite, 5 molybdenum sulfide or else barium sulfate doped with tin or antimony. Iron phosphide is particularly preferred. The conductivity pigments or fillers are added in order to improve the weldability or to improve coating with an electrodeposition lacquer. In addition, silica suspensions, 10 in particular when using anti-corrosive agents for aluminum substrates, may be used. These inorganic auxiliary substances should be present in a finely divided form, that is with average particle diameters of between 0.005 and 5 Am, preferably between 0.05 and 2.5 pm. The auxiliary 15 substances are used in proportions of between 0.1 and 30 wt.%. Furthermore, the compositions may contain additives to improve the shaping process, these being, for example, wax 20 based derivatives based on natural or synthetic waxes, e.g. polyethylene or polytetrafluoroethylene (PTFE) waxes or wax derivatives. The pH of the solutions being applied, that is the original 25 composition or a variant diluted with more water, is between 0.5 and 4.0, preferably between 0.7 and 2.5. When applying in particular to metal strip surfaces, the application solution is applied in a manner known per se by roller application (chem-coating), wiping, immersion/ 30 squeezing or spraying/squeezing to an, optionally metal coated, steel strip or (alloyed) aluminum strip. Application is performed at temperatures between 10 and 50 0 C, preferably between 15 and 35 0 C. The temperature may be adjusted by supplying heat via the workpiece or the 35 treatment solution. Finally, due to appropriate management of the heat supply, the formation of a film and cross linking of this film and anchoring to the metallic surface WO 00/71626 U/ /ruuI u-2 ., 20 all take place at the same time. For this to occur, peak metal temperatures (PMT) of 50 to 150 0 C are achieved for a period of between 1 and 120 seconds, preferably between 1 and 30 seconds. The weight per unit area of the coating 5 after drying is then 0.1 to 5, preferably 0.5 to 3.0 g/m 2 and particularly preferably 0.8 to 2 g/m 2 . The weight per unit area which can be produced in this way can be varied between wide limits, but it is much higher than that which could be produced by the prior art. 10 The layers produced in this way may be coated with the conventional lacquer systems used in the domestic appliance and/or architectural sectors, that is the application of a liquid primer followed by coating with a liquid topcoat may 15 be performed, or else powder coating with a single-layered lacquer may take place. Furthermore, the anti-corrosive layer according to the invention may be coated directly, that is without the application of a primer, with typical strip topcoats. The layers produced in this way protect the 20 metal sheeting and provide adequate protection against corrosion. Thus, for example, when coating (alloy) galvanized steel, the salt spray test in accordance with DIN 50021 SS is withstood for more than 250 hours. Likewise, in the case of (alloyed) aluminum, a salt spray 25 test in accordance with DIN 50021 ESS is successfully withstood for more than 250 hours. Also, a climate controlled test in accordance with DIN 50017 KK for (alloy) galvanized steel is withstood for more than 3 weeks without the formation of white rust. The corrosion resistance of 30 materials which have been treated with the anti-corrosive compositions according to the invention, with or without a primer coating, achieve the values which can be achieved with a conventional treatment. The reshaping behaviour is improved when compared with substrates which have not been 35 coated in accordance with the invention, furthermore substrates coated in accordance with the invention can be catophoretically lacquered under the same conditions and WO 0U/71b2b r./ .ruu, u- d., 21 with the same results as materials which have been phosphatized in the way typically used in the automobile industry. The process according to the invention may also be used instead of traditional chromatizing and 5 phosphatizing processes when subsequent coating with a further anti-corrosive layer such as GranocoatTM and the like is intended to be performed. If treatment according to the invention takes place 10 immediately after a metallic surface finishing process, e.g. electrolytic galvanizing or hot melt dip galvanizing of steel strips, then the strips may be placed in contact with the treatment solution according to the invention without first being cleansed. However, if the metal strips 15 to be treated have been stored and/or transported prior to coating according to the invention, then they have generally been provided with anti-corrosive oils or at least have been so heavily contaminated that cleansing is required prior to coating according to the invention. This 20 may take place using normal weakly to strongly alkaline cleansers; in the case of aluminum and its alloys also with acid cleansers. When being applied to aluminum and aluminum alloys, the 25 anti-corrosive composition according to the invention may also contain very low concentrations of organophosphonic acid and optionally may contain no organophosphonic acid. The invention is explained in more detail in the following 30 by using a few working examples. All data relating to amounts in the compositions are parts by weight unless stated otherwise. The individual components listed in table 1 are generally 35 mixed in the sequence given and at room temperature.

WO 00/71626 kLX/JSLUUI U'doI 22 I 0 - e4 ) 0 N0 L M 0 O N- vi '01 06 I CI (N ( a I Ce ~0 M O '010 04 CI 04 (N 0NaI( C) 0 C.'00 co 0 ) 0n)ON (0 CO'1 a I a ( N N) 0- (O CO 'O LO) 04 a N a C a a 0 C) 00 C)0 M 'C M 'M LO) a a ( (N CVI ~0 0l 0 CC) 0 L6 CO 00 (NU I-- N0( C) CO N Y (N a i a I I-C C CR (q I- ce)6 (0'0 N0 C) ) (6N M '0 (N '0 MON I CV) a a a - c It 0 N (0 M U") 0 N a N a a a a a a a '- c LO C) T- r- MCO ' U) 0 a a a a r c a) E E aa a >1 >1> 0~ 0 0 00 5 Ca c _r_ Cua ~ a- V 0 ~CU c 0 0 (D ~ CL0 Q- _r) 05 0 0 (D Cl0 CD CLI) CL) 0 Cc U Cu 0 0 .0 o - O0*E. 0 .CU cu 0- 2D H-C 00 (D . N ~ E ~ a LE0 o P ~ -5 0 16 > cac M 0 E 0 > 0 c> CL 0 ' (D C:r- > I E41 w2ll In WVu UI~~ '.~ru uv/z/Ib, 23 wn 0 0 An Ceo ct.) 0 *0 0 c E Chl 0 Cc C6C (D) CD L EDi = oo CL Co Cu 0 0) 0) C cc 5%0 0. U, x ca 0 L. 0 0 1 C'6 0) CD r- Z Cu CuLU V 00 V -50 Cu C oC C 0 LO) 0.D -E Cu 0) CD Cu ZE o Cur (D - : V VCU CuC C. o CU 0 V) Cu CC ccu Cuo U Co - o Cu - . z C: -5 o - Cu 0 c o. C ca a) ~ ) ( £u - Cu Cu Cu_ N Cu 0 Cu T Cu a C - 0 f Cu m 0 Cu _O . C C VL D -) C Cu: U- 0) c -0 E5 ZA D 0 -C Cu Cu V0 N -0 d 0 0 CN Cu C C 0. Cu = o Z) C 0CE.CLE0 0. m D 0 0 C .02 cn LO . Cu E C- ce 0 c: 0 0.0 0 V) 0 0. c Cu 0 Cu Cu V U) 0.- C () -0~ Cu ~ 0 ~ C ~ .C -% 0 -a cn (N CuCm 0 C: 0. cau - O 0 Lt o 0 CC Cu* U, 07 -2 f C e, bE u E o 0 u Co 2) - 0 Cu 0 Cu 0) 0 w- 0 LO Cu COC .C Cu C 0 u- Cu V0 M 0S 002E0) c (DC L WO 00/71626 r.a/ lU/ ' 24 Examples 1 to 3 and 6 and 7 listed in table 1 are not in accordance with the invention, they exhibit significant attack by white rust on galvanized steel after about 100 5 hours in the test according to DIN 50021 SS. Examples 4, 5 and 15 give good results for the anti-corrosive effect on aluminum, examples 8 to 14 give good results for the anti corrosive effect on galvanized steel.

Claims (15)

1. A chromium-free anti-corrosive agent for single-stage coating of metal substrates, containing 5 a) 0.5 to 100 g/l of hexafluoro anions of titanium(IV), silicon(IV) and/or zirconium(IV), b) 0 to 100 g/l of phosphoric acid, 10 c) 0 to 100 g/l of one or more compounds of cobalt, nickel, vanadium, iron, manganese, molybdenum or tungsten, 15 d) 0.5 to 30 wt.% of at least one water-soluble or water-dispersible film-producing organic polymer or copolymer, e) 0.1 to 10 wt.% of an organophosphonic acid, 20 f) optionally further auxiliary substances and additives.

2. An anti-corrosive agent as claimed in claim 1, wherein 25 the film-producing (co)polymer is chosen from epoxide resins, styrene copolymers, butadiene copolymers, polyurethanes, melamine resins, (meth)acrylate polymers or mixtures of these. 30

3. An anti-corrosive agent as claimed in claim 2, wherein at least one film-producing (co)polymer contains cross-linkable functional groups.

4. An anti-corrosive agent as claimed in claim 3, wherein 35 it also contains a cross-linking agent. WO 00/71626 PCT/EPOO/04267 26

5. An anti-corrosive agent as claimed in at least one of the preceding claims, wherein it contains 0.1 to 30 wt.% of a conductivity pigment and/or a further inorganic auxiliary substance as a further additive. 5

6. An anti-corrosive agent as claimed in claim 5, wherein the conductivity pigment is chosen from carbon black, graphite, molybdenum sulfide, doped barium sulfate, iron phosphide, vanadium carbide, titanium nitride. 10

7. An anti-corrosive agent as claimed in claim 5 or 6, wherein the conductivity pigment or the further inorganic auxiliary substance has an average particle diameter of 0.005 to 5 pm, preferably 0.05 to 2.5 pm. 15

8. An anti-corrosive agent as claimed in at least one of the preceding claims, wherein it contains shaping aids based on natural or synthetic waxes, e.g. polyethylene or polytetrafluoroethylene waxes and/or waxes or wax 20 derivatives as further additives.

9. An anti-corrosive agent as claimed in at least one of the preceding claims, wherein it has a pH in the range 0.5 to 4.0, preferably 0.7 to 2.5. 25

10. A process for the anti-corrosive treatment of (optionally metal-coated) steel or aluminum or its alloys, wherein a) the surface of the metal is placed in contact 30 with an anti-corrosive agent as claimed in at least one of the preceding claims for a period between 0.5 and 60 seconds, b) excess anti-corrosive agent is optionally removed from the surface and 35 c) the treated substrate is heated to peak metal temperatures between 50 0 C and 150 0 C for a period of 1 to 120 seconds by the appropriate supply of WO 00/71626 PCT/EPOO/04267 27 heat, wherein cross-linking of the polymer film and its anchoring to the metal surface take place at the same time. 5

11. A process as claimed in claim 10, wherein the metallic coating of steel is chosen from hot-melt dip galvanizing, alloy galvanizing, electrolytic galvanizing, copper plating, nickel plating or aluminization. 10

12. A process as claimed in claim 10 or 11, wherein the corrosion protection agent is applied to the surface of the workpiece by flooding/squeezing, spraying/ squeezing or suitable wiper or roller methods of 15 application.

13. A steel or aluminum strip coated by a process as claimed in claims 10 to 12, wherein the weight per unit area of the layer is between 0.1 and 5, 20 preferably between 0.5 and 2.0 g/m 2 .

14. A process for the anti-corrosive treatment of aluminum as claimed in one of claims 10 to 13, wherein the anti-corrosive agent as claimed in claims 1 to 9 25 contains no organophosphonic acid.

15. A steel or aluminum strip coated by a process as claimed in claims 10 to 14, wherein a lacquer undercoat (primer) is not required when coating in a 30 coil-coating process.