Resource-saving method for activating metal surfaces before phosphate treatment

Abstract

The present invention relates to a method for phosphating metal surfaces in a layer-forming manner using, as an activation step, an aqueous colloidal solution containing dispersed particulate components, which, in addition to a dispersed inorganic compound of a phosphate of a polyvalent metal cation, contain a polymeric organic compound as a dispersant at least partially composed of styrene and / or an α-olefin having 5 or fewer carbon atoms and at least partially composed of maleic acid, its anhydrides and / or its imides, and which polymeric organic compound further comprises polyoxyalkylene units. The washing and rinsing steps preceding the activation step, as well as the activation step itself, can be carried out using tap water, in a resource-saving manner, without loss of activation performance, using an aqueous colloidal solution containing at least 0.5 mmol / L of alkaline earth metal ions dissolved in water.

Description

[Technical Field]

[0001] The present invention relates to a method for phosphate treatment of a metal surface in a layer-forming manner using a colloidal aqueous solution as an activation step, wherein the method contains dispersed particulate components, and the particulate components contain, in addition to an inorganic compound in which polyvalent metal cation phosphates are dispersed, a polymeric organic compound as a dispersant, which is at least partially composed of styrene and / or an α-olefin having 5 or fewer carbon atoms and is partially composed of maleic acid, its anhydride and / or its imide, and the polymeric organic compound further contains polyoxyalkylene units. The washing and rinsing steps preceding the activation step, as well as the activation step itself, can be carried out using tap water in a resource-saving manner, without losing activation performance, by using a colloidal aqueous solution containing at least 0.5 mmol / L of alkaline earth metal ions dissolved in water. [Background technology]

[0002] Layer-forming phosphate treatment is a method of applying crystalline corrosion-preventive coatings to metal surfaces, particularly to metal materials such as iron, zinc, and aluminum, and has been used and studied in detail for decades. Zinc phosphate treatment, which is particularly well-established for corrosion protection, is performed using layer thicknesses of several micrometers and is based on corrosive acid cleaning of the metal material in an acidic aqueous composition containing zinc ions and phosphate. During the acid cleaning process, an alkali diffusion layer is formed on the metal surface, which extends into the interior of the solution, where sparingly soluble crystallites are formed, which precipitate directly at the interface with the metal material and continue to grow there. To assist the acid cleaning reaction on the metallic aluminum material and to mask the toxic aluminum bath which interferes with layer formation on the metal material in soluble form, water-soluble compounds that are sources of fluoride ions are often added. Zinc phosphate treatment is always initiated by the activation of the metal surface by the component being phosphorylated. Wet chemical activation is conventionally carried out by contact with a colloidal aqueous solution of phosphate ("activation step"), and the phosphate, as long as it is immobilized on the metal surface, is used as a growth nucleus for forming a crystalline coating within the alkaline diffusion layer in subsequent phosphate treatments. A suitable dispersion in this case is a colloidal, mostly neutral to alkaline aqueous composition based on phosphate crystallites, having only slight crystallographic deviations of the crystalline structure from the type of zinc phosphate layer being deposited. In this regard, for example, International Publication No. 98 / 39498 teaches divalent and trivalent phosphates of metallic Zn, Fe, Mn, Ni, Co, Ca, and Al, and it is technically preferable that metallic zinc phosphates be used for activation for subsequent zinc phosphate treatments.

[0003] The activation step based on the dispersion of divalent and trivalent phosphates requires a high level of process control to maintain optimal activation performance, especially when treating a series of metal components. To ensure the method is sufficiently robust, foreign ions carried over from the previous treatment bath or aging process in the colloidal aqueous solution must not degrade the activation performance. Degradation is first evident in an increase in layer weight in the subsequent phosphate treatment, eventually leading to the formation of a defective or non-uniform phosphate layer. Therefore, when the process is carried out continuously, it is necessary to prevent the carryover of foreign ions, and thus the rinsing step prior to the activation step and the activation step itself must be performed with deionized water or additives to extend the bath life and / or to reduce the consumption of colloidal active components to the extent that the phosphate treatment based on the colloidal aqueous solution can be economically carried out. Previously, the addition of additives was always necessary, and when activating with particulate phosphates, this process typically involved the addition of condensed phosphates for colloidal stabilization, and, additionally or alternatively, the use of other complexing agents to mask water hardness or polyvalent metal ions carried over from previous washing and rinsing stages to counteract the accelerated formation of colloidal aggregates and thus the sedimentation of colloidally dispersed bath species. The dosage of condensed phosphates and / or complexing agents requires precise analytical monitoring because there is both a process-critical minimum amount to be maintained and a system-specific upper limit, and the amount of condensed phosphates and / or complexing agents below this minimum or above this upper limit adversely affects the activation performance. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 98 / 39498 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Therefore, the activation step of a pretreatment line for phosphate treatment, particularly zinc phosphate treatment, intended to be carried out based on a colloidal aqueous solution of phosphate, needs to be made more efficient in terms of its properties for activating metal surfaces for phosphate treatment, and the step needs to be made more robust in terms of the process. This relates, in particular, to the ability of the colloidal aqueous solution to activate the metal surface to be phosphated as uniformly and comprehensively as possible using a relatively small amount of material, and thus to the formation of a homogeneous and fine crystalline coating in the phosphate treatment step, resulting in excellent coating adhesion properties, as well as high charge transfer resistance in the subsequent electrocoating, and therefore good coating grip. Furthermore, in embodiments that improve the robustness of such a method, it is necessary to ensure that the structural and chemical state of the colloidal components has higher resistance and higher stability to carryover and accumulated foreign ions. The objective of all this is to establish a pretreatment line for phosphate treatment, particularly zinc phosphate treatment, that can be carried out continuously with low technical complexity in a resource-saving manner. [Means for solving the problem]

[0006] This complex operational profile is remarkably addressed by the use of specific polymer dispersants to stabilize the colloidal components in the activation step based on particulate phosphates. The highly efficient stabilization of the particulate components that lead to activation allows the special dispersants to produce a uniform, closed phosphate coating even with relatively low colloidal concentrations, ensuring that the colloidal content is maintained and consistent without a significant decrease in activation performance after the pretreatment line reaches a quiescent state. Therefore, the use of specific dispersants makes it possible to completely eliminate the addition of condensed phosphates, thus significantly reducing the technical complexity of continuously implementing the phosphate treatment method.

[0007] Accordingly, the present invention relates to a method for pre-treatment of a metallic material selected from zinc, iron, or aluminum, or a component at least partially composed of such a metallic material, wherein the metallic material or component is subjected to a series of method steps, first activation (i), then phosphate treatment (ii), particularly zinc phosphate treatment, wherein the activation in method step (i) is carried out by contacting the metallic material or component with a colloidal aqueous solution, the colloidal aqueous solution being a dispersed particulate component (a) solution, (a1) at least one particulate inorganic compound comprising a phosphate of a polyvalent metal cation at least partially selected from hopeite, phosphophyllite, scholzite and / or halolite, and (a2) Contains at least one polymeric organic compound which is at least partially composed of styrene and / or an α-olefin having 5 or fewer carbon atoms, and at least partially composed of maleic acid, its anhydride and / or its imide, and further contains polyoxyalkylene units, The present invention relates to a method for preparing a colloidal aqueous solution containing at least 0.5 mmol / L of alkaline earth metal ions dissolved in water. [Modes for carrying out the invention]

[0008] In the activation (i) of the method according to the present invention, the dispersed particulate component (a) of the colloidal aqueous solution is the solid content remaining after drying the retained liquid of an ultrafiltration of a specified partial volume of an aqueous dispersion having a nominal cutoff limit of 10 kD (NMWC: nominal molecular weight cutoff). The ultrafiltration is performed in the filtrate for 10 μS cm. -1 Deionized water (κ < 1 μS cm) until conductivity less than 1 μS cm is measured -1 This is done by adding ).

[0009] In the context of this invention, an organic compound is a polymer if its weight-average molar mass is greater than 500 g / mol. The molar mass is determined using a molar mass distribution curve of a sample of relevant reference values, which is experimentally established at 30°C by size exclusion chromatography using a concentration-dependent refractive index detector and calibrated against a polyethylene glycol standard. The average molar mass is analyzed using a computer according to a strip method with a cubic calibration curve. Hydroxylated polymethacrylate is preferred as the column material, and aqueous solutions of 0.2 mol / L sodium chloride, 0.02 mol / L sodium hydroxide, and 6.5 mmol / L ammonium hydroxide are preferred as the eluents.

[0010] The high resistance of the method according to the present invention to carried-over foreign ions also allows the washing and rinsing steps performed before the activation step, as well as the activation step itself, to be carried out with tap water instead of deionized water. In this way, the method according to the present invention is carried out in a particularly resource-saving manner. Accordingly, according to the present invention, it is preferable that the colloidal aqueous solution in the activation contains at least 1.0 mmol / L, particularly preferably at least 1.5 mmol / L, of alkaline earth metal ions dissolved in water.

[0011] This advantage over conventional activation baths is particularly evident when components are phosphated in series, i.e., during continuous operation of a pretreatment line for phosphate treatment. Therefore, in a preferred embodiment of the method according to the present invention, a number of specific components, at least partially consisting of zinc, iron, or aluminum, are treated in series. The continuous pretreatment is when the number of components come into contact with a colloidal aqueous solution placed in a system tank for the activation stage, with each component coming into contact with the solution successively and therefore at different times, and the components are then supplied to the phosphate treatment process. In this case, the system tank is a container in which a colloidal aqueous solution is placed for activation for phosphate treatment in series.

[0012] If the tolerance of the method according to the present invention reaches the system-specific limit in any case due to very high ionic strength, e.g., high permanent water hardness, and simultaneously high levels of foreign ions carried over from the previous washing stage, an organic complexing agent can be added to mask the foreign ions in order to maintain a long bath life. In this case, it must be evaluated whether the economic advantage of being able to perform the activation stage and, if necessary, the preceding washing stage, and rinse with tap water, is not hindered by the addition of the organic complexing agent in the system tank during the activation stage and their technical monitoring. In connection therewith, preferred suitable organic complexing agents are selected from α-hydroxycarboxylic acids, which are then preferably selected from gluconic acid, tartaric acid, glycolic acid, citric acid, tartaric acid, lactic acid, very particularly preferably gluconic acid and / or organic phosphonic acids, which are then preferably selected from etidronic acid, aminotris(methylenephosphonic acid), aminotris(methylenephosphonic acid), phosphonobutane-1,2,4-tricarboxylic acid, diethylenetriaminepenta(methylenephosphonic acid), hexamethylenediaminetetra(methylenephosphonic acid) and / or hydroxyphosphonoacetic acid, particularly preferably selected from etidronic acid.

[0013] To maintain stable activation performance, the amount of organic complexing agent in the colloidal aqueous solution should preferably be 2 times or less the amount of alkaline earth metal ions, particularly preferably 1.5 times or less, and very preferably up to a certain extent that it is equimolar or less the amount of alkaline earth metal ions.

[0014] In the method according to the present invention, the phosphate treatment can be carried out in a stable manner, that is, mostly without the addition of complexing agents, until the water hardness corresponds to 10 mmol / L of alkaline earth metal ions in the activation stage. Therefore, in a preferred embodiment of the method according to the present invention, the colloidal aqueous solution preferably contains 10 mmol / L or less, and particularly preferably 5 mmol / L or less, of alkaline earth metal ions dissolved in water.

[0015] Another advantage of the method according to the invention compared to the conventional activation methods is that the addition of condensed phosphates in the activation step can be omitted. Condensed phosphates dissolved in the aqueous phase of the activation fulfill the task of masking permanent water hardness and, based on experience, stabilize the content of hopeite, phosphophyllite, sholzite and / or harlite, which are phosphates, at the colloidal level, especially during the continuous operation of the pretreatment line, and thus fulfill the specific task of keeping the phosphates permanently available for activation. In the method according to the invention based on the activation step based on the particulate component (a), the fact that the addition of condensed phosphates can be omitted is surprising to a person skilled in the art.

[0016] Overall, in the context of the present invention, the addition of condensed phosphates can thus be completely omitted, and thus the activation contains only a small amount of condensed phosphates that pass from the previous washing step containing the component to be pretreated to the activation step, especially when treating a large number of components in series. In a preferred embodiment of the method according to the invention, the content of condensed phosphates dissolved in the water in the colloidal aqueous solution is in each case less than 0.25, preferably less than 0.20, particularly preferably less than 0.15, very preferably less than 0.10, based on the phosphate content of at least one particulate compound (a1) based on elemental P.

[0017] Furthermore, in this context, the content of condensed phosphates dissolved in the water in the colloidal aqueous solution is preferably calculated as P and is less than 20 mg / kg, preferably less than 15 mg / kg, particularly preferably less than 10 mg / kg, based on the colloidal aqueous solution.

[0018] In the context of the present invention, the condensed phosphates are metaphosphates and polyphosphates, preferably polyphosphates, particularly preferably pyrophosphates. The condensed phosphates are preferably in the form of compounds of monovalent cations, preferably selected from Li, Na and / or K, particularly preferably Na and / or K.

[0019] The content of the condensed phosphate can be analytically determined from the difference in the total phosphate content in the non-particulate components of the colloidal aqueous solution, regardless of the presence or absence of oxidative digestion with peroxodisulfate. The dissolved orthophosphate content is quantified by photometry. Alternatively, when polyphosphate is used as the condensed phosphate, enzymatic digestion with pyrophosphatase can be carried out instead of oxidative digestion. The non-particulate components of the colloidal aqueous solution are the solid content of the colloidal aqueous solution in the permeate of the above ultrafiltration after drying to a constant mass at 105 °C, i.e., the solid content after the particulate components (a) have been separated by ultrafiltration.

[0020] The colloidal aqueous solution in the activation (i) of the method according to the invention preferably has an alkaline pH, particularly preferably above 8.0, even more preferably above 9.0, but preferably below 11.0, and it is possible to use compounds that affect the pH, such as phosphoric acid, sodium hydroxide solution, ammonium hydroxide or ammonia, to adjust the pH. "pH" as used in the context of the present invention corresponds to the negative common logarithm of the hydronium ion activity at 20 °C and can be determined by a pH-sensitive glass electrode.

[0021] For good activation performance, it is necessary to use polyvalent metal cations in the form of phosphates, which should be contained in the dispersed particulate component (a) for activation in a correspondingly high proportion. Therefore, the phosphate content in at least one particulate inorganic compound (a1) is preferably at least 25% by weight, particularly preferably at least 35% by weight, particularly more preferably at least 40% by weight, and very preferably at least 45% by weight, based on the dispersed particulate component (a) of the colloidal aqueous solution. The inorganic particulate component of the colloidal aqueous solution then remains when the particulate component (a) obtained from drying the retained liquid of ultrafiltration is thermally decomposed in the reactor by supplying a CO2-free oxygen stream at 900°C without mixing of catalysts or other additives until an infrared sensor provides the same signal as a CO2-free carrier gas (blank value) at the outlet of the reactor. The phosphate contained in the inorganic particulate component is determined directly from the acid digestion as the phosphorus content by atomic emission spectrometry (ICP-OES) after acid digestion of the component with a 10% by weight HNO3 aqueous solution at 25°C for 15 minutes.

[0022] The active component of the colloidal aqueous dispersion that effectively promotes the formation of a closed phosphate coating on a metal surface and thus activates the metal surface is, as already stated, mainly composed of phosphates, which then result in the formation of a fine crystalline coating, and is therefore at least partially selected from hopeite, phosphophyllite, scholzite and / or halorite, preferably at least partially selected from hopeite, phosphophyllite and / or scholzite, particularly preferably at least partially selected from hopeite and / or phosphophyllite, and very preferably at least partially selected from hopeite. Thus, activation within the scope of the present invention is substantially based on phosphates in particulate form included in the activation step. Without considering crystal water, hopeite stoichiometrically contains Zn3(PO4)2 and nickel-containing and manganese-containing variants Zn2Mn(PO4)3 and Zn2Ni(PO4)3, while phosphophyllite consists of Zn2Fe(PO4)3, scholzite consists of Zn2Ca(PO4)3, and halorite consists of Mn3(PO4)2. The presence of crystalline phases of hopeite, phosphophyllite, scholzite, and / or halorite in the aqueous dispersion according to the present invention can be demonstrated by separation of particulate components (a) by ultrafiltration at the nominal cutoff limit of 10 kD (NMWC: nominal molecular weight cutoff) and by X-ray diffraction (XRD) after drying the holding solution to a constant mass at 105°C.

[0023] Because the presence of zinc ions and phosphates having a specific crystallineity is preferred, in the method according to the present invention, in order to form a crystalline zinc phosphate coating that adheres firmly after successful activation, it is preferable that the colloidal aqueous dispersion contains at least 20% by weight, particularly preferably at least 30% by weight, and particularly more preferably at least 40% by weight, of zinc in the inorganic particulate components of the colloidal aqueous solution, which is calculated as PO4 based on the phosphate content of the inorganic particulate components.

[0024] Another advantage of the method according to the present invention is that even if the proportion of particulate inorganic compound (a1) in activation (i) is small, it is sufficient to achieve full activation performance for the materials zinc, aluminum, and iron. Accordingly, according to the present invention, the content of dispersed particulate component (a) in the colloidal aqueous solution is, in any case, at least 0.05 g / kg, preferably at least 0.1 g / kg, particularly preferably at least 0.2 g / kg, but preferably 10 g / kg or less, particularly preferably 2 g / kg or less, and very preferably 1 g / kg or less, based on the colloidal aqueous solution.

[0025] However, within the scope of the present invention, activation is preferably not achieved by a colloidal solution of titanium phosphate, because otherwise, layer-forming zinc phosphate treatment on iron, particularly steel, cannot be reliably achieved. Therefore, in preferred embodiments of the method according to the present invention, the titanium content in the inorganic particulate components of the colloidal aqueous solution is less than 0.01% by weight, particularly preferably less than 0.001% by weight, based on the colloidal aqueous solution. In particularly preferred embodiments, the activated colloidal aqueous solution (i) contains less than 10 mg / kg of titanium in total, particularly preferably less than 1 mg / kg.

[0026] The activation step in the method according to the present invention is further characterized by its D50 value, and exceeding this value significantly reduces the activation performance. The D50 value of the colloidal aqueous solution is preferably less than 1 μm, and particularly preferably less than 0.4 μm. In the context of the present invention, the D50 value represents the particle size not exceeding 50 volume percent of the particulate components contained in the colloidal aqueous solution. According to ISO 13320:2009, the D50 value is determined according to Mie theory by the refractive index n of spherical particles and scattered particles immediately after the sample is taken from the activation step. D Using =1.52-i·0.1, the volume-weighted cumulative particle size distribution can be determined at 20°C from scattered light analysis.

[0027] Within the scope of the present invention, the polymeric organic compound (a2) used as a dispersant and having polyoxyalkylene units is composed of at least partially styrene and / or α-olefins having 5 or fewer carbon atoms, and maleic acid, its anhydride and / or its imide, which provides extremely high stability of the colloidal aqueous solution in the activation step of the method according to the present invention.

[0028] In this case, the α-olefin is preferably selected from ethene, 1-propene, 1-butene, isobutylene, 1-pentene, 2-methylbuta-1-ene and / or 3-methylbuta-1-ene, and particularly preferably selected from isobutylene. It will be apparent to those skilled in the art that the polymeric organic compound (a2) contains these monomers as unsaturated structural units covalently bonded to each other or to other structural units. Suitable commercial representatives include, for example, Dispex® CX 4320 (BASF SE), a maleic acid-isobutylene copolymer modified with polypropylene glycol; Tego® Dispers 752 W (Evonik Industries AG), a maleic acid-styrene copolymer modified with polyethylene glycol; or Edaplan® 490 (Munzing Chemie GmbH), a maleic acid-styrene copolymer modified with EO / PO and imidazole units. In the context of the present invention, a polymeric organic compound (a2) composed at least partially of styrene is preferred.

[0029] The polymeric organic compound (a2) used as a dispersant is preferably composed of 1,2-ethanediol and / or 1,2-propanediol, and particularly preferably has polyoxyalkylene units composed of both 1,2-ethanediol and 1,2-propanediol. The content of 1,2-propanediol in the total polyoxyalkylene units is preferably at least 15% by weight, and particularly preferably 40% by weight or less, relative to the total polyoxyalkylene units. It is also preferable that the side chains of the polymeric organic compound (a2) contain polyoxyalkylene units. A content of polyoxyalkylene units in the total polymeric organic compound (a2) of at least 40% by weight or more, particularly preferably at least 50% by weight, and preferably 70% by weight or less, is advantageous for dispersibility.

[0030] To immobilize inorganic particulate components and dispersants of a colloidal aqueous solution, which are at least partially formed by polyvalent metal cations in the form of phosphates selected from hopeite, phosphophyllite, scholzite and / or halite, the polymeric organic compound (a2) preferably also contains N-heterocyclic units, which are then preferably selected from pyridine, imidazole, imidazoline, morpholine, pyrrole and / or pyrrolidone units, particularly preferably selected from imidazole and / or imidazoline units, and particularly more preferably selected from imidazole units. Each of these N-heterocyclic units is preferably part of a side chain of the polymeric organic compound (a2), and within the side chain, preferably via at least three carbon atoms, aliphatically attached to the main chain such that a polyoxyalkylene unit of the polymeric organic compound (a2) is at least partially end-capped with an N-heterocyclic group, and therefore in a preferred embodiment, a terminal N-heterocyclic group is present on the polyoxyalkylene side chain. The N-heterocyclic unit is preferably covalently bonded via the nitrogen atom of the heterocycle in the side chain of the polymeric organic compound (a2), preferably in the side chain having a polyoxyalkylene unit. The N-heterocyclic unit is preferably in a form that is at least partially quaternized, and particularly preferably as an N-alkylated quaternary N-heterocyclic unit.

[0031] In preferred embodiments, the amine value of the organic polymer compound (a2) is at least 25 mg KOH / g, particularly preferably at least 40 mg KOH / g, but preferably less than 125 mg KOH / g, particularly preferably less than 80 mg KOH / g, and therefore, in preferred embodiments, the entire polymeric organic compound in the particulate component (a) also has these preferred amine values. In either case, the amine value is determined by weighing approximately 1 g of the relevant reference value—the organic polymer compound (a2) or the entire polymeric organic compound in the particulate component—in 100 mL of ethanol, and the titration is performed using a 0.1 N HCl titration solution against the indicator bromophenol blue until the color changes to yellow at the temperature of the ethanol solution at 20°C. Multiplying the amount of HCl titration solution used in milliliters by a factor of 5.61 and dividing by the exact mass in grams corresponds to the milligram amine value of KOH per gram of the relevant reference value.

[0032] As long as maleic acid is a component of the organic polymer compound (a2) as a free acid rather than in the form of anhydrous or imide, the presence of maleic acid can confer increased water solubility of the dispersant, particularly in the alkaline range. Therefore, in order to ensure a sufficient number of polyoxyalkylene units, it is preferable that the entire polymer organic compound (a2), preferably in the particulate component (a), has an acid value of at least 25 mg KOH / g, preferably less than 100 mg KOH / g, and particularly preferably less than 70 mg KOH / g, according to DGF CV 2(06) (as of April 2018). It is also preferable that the entire polymer organic compound (a2), preferably in the particulate component (a), in either case has a hydroxyl value of less than 15 mg KOH / g, particularly preferably less than 12 mg KOH / g, and particularly more preferably less than 10 mg KOH / g, as determined according to Method A of European Pharmacopoeia 9.0 01 / 2008:20503.

[0033] In order to sufficiently disperse the inorganic particulate components in a colloidal aqueous dispersion, the content of the polymeric organic compound (a2), preferably the total amount of polymeric organic compounds in the particulate components (a) based on the particulate components (a), is sufficient to be at least 3% by weight, particularly preferably at least 6% by weight, but preferably not exceeding 15% by weight.

[0034] In a further embodiment, the present invention relates to a method for pre-treatment of corrosion based on phosphate treatment, comprising an aqueous dispersion. Such a method according to the present invention relates to pre-treatment of a metallic material selected from zinc, iron, or aluminum, or a component at least partially composed of such a metallic material, wherein the metallic material or component is subjected in a series of method steps, first to activation (i), then to phosphate treatment (ii), particularly zinc phosphate treatment, wherein the activation in method step (i) is carried out by contacting at least one metallic material of the metallic material or component with the above-mentioned colloidal aqueous solution, which can be obtained as an aqueous dispersion diluted 20 to 100,000 times, the colloidal aqueous solution -Based on an aqueous dispersion, at least 5% by weight of dispersed particulate components (A), (A1) At least one particulate inorganic compound comprising a phosphate of a polyvalent metal cation at least partially selected from hopeite, phosphophyllite, scholzite and / or halolite, (A2) A dispersed particulate component (A) comprising at least one polymeric organic compound which is at least partially composed of styrene and / or an α-olefin having 5 or fewer carbon atoms, and which is at least partially composed of maleic acid, its anhydride and / or its imide, and further comprises polyoxyalkylene units, and -Optionally, comprising at least one thickener (B) selected from urea urethane resins having an amine value of less than 8 mg KOH / g, more preferably less than 5 mg KOH / g, and more preferably less than 2 mg KOH / g, The dilution is carried out with water containing alkaline earth metal ions dissolved in water at a concentration of at least 0.5 mmol / L, preferably at least 1 mmol / L, and particularly preferably at least 1.5 mmol / L, but more preferably with water containing alkaline earth metal ions dissolved in water at a concentration of 10 mmol / L or less, and particularly preferably 6 mmol / L or less.

[0035] The same definitions and preferred specifications as those given above for colloidal aqueous solutions apply to the dispersed particulate components (A), as well as to at least one particulate inorganic compound (A1) and a polymeric organic compound (A2).

[0036] Due to the excellent colloidal stability of the particulate component (A) by the high-molecular-weight organic compound (A2) as a dispersant, dilution is performed using deionized water (κ < 1 μS cm) in order to conserve resources as much as possible in the method according to the present invention. -1 ), and especially preferably, tap water is used. In light of the underlying technical application, tap water contains at least 0.5 mmol / L of alkaline earth metal ions.

[0037] The presence of the thickener, component (B), in combination with its particulate components, imparts thixotropic flow behavior to the aqueous dispersion, thereby contributing to the prevention of irreversible formation of aggregates in the particulate components of the dispersion from which primary particles cannot be detached. The addition of the thickener is preferably controlled so that the aqueous dispersion has a maximum kinematic viscosity of at least 1000 Pa·s, preferably less than 5000 Pa·s, at a temperature of 25°C and a shear rate range of 0.001 to 0.25 per second, and preferably exhibits shear deviscation behavior at 25°C at shear rates exceeding the shear rate at which the maximum kinematic viscosity exists, i.e., viscosity decreases as the shear rate increases, resulting in the entire aqueous dispersion exhibiting thixotropic flow behavior. The viscosity over the specified shear rate range can be determined using a cone-plate viscometer having a cone diameter of 35 mm and a gap width of 0.047 mm.

[0038] The thickening agent in component (B) is a high-molecular-weight compound or deionized water at a temperature of 25°C (κ < 1 μS cm).-1 The specified mixture of chemical compounds having a Brookfield viscosity of at least 100 mPa·s at a shear rate of 60 rpm (= revolutions per minute) using a size 2 spindle, with 0.5 wt% of the component being used. To determine the thickening properties of this mixture, the mixture must be mixed with water by adding the corresponding amount of polymer compound to the aqueous phase at 25°C with stirring, then removing air bubbles from the homogenized mixture in an ultrasonic bath and letting it stand for 24 hours. The viscosity measurement is then read within 5 seconds immediately after applying a shear rate of 60 rpm using a size 2 spindle.

[0039] The aqueous dispersion according to the present invention preferably contains one or more thickeners, preferably at least 0.5% by weight in total, preferably 4% by weight or less, and particularly preferably 3% by weight or less, of component (B), and the total content of high-molecular-weight organic compounds in the non-particulate components of the aqueous dispersion also preferably does not exceed 4% by weight (based on the dispersion). The non-particulate components are the solid content of the aqueous dispersion in the permeate of the ultrafiltration described above after drying to a certain mass at 105°C, i.e., the solid content after the particulate components have been separated by ultrafiltration.

[0040] Certain classes of polymer compounds are particularly suitable thickeners for component (B) and are readily available commercially. In this regard, the thickener for component (B) is particularly preferably selected from polymeric organic compounds, which are then preferably selected from polysaccharides, cellulose derivatives, aminoplasts, polyvinyl alcohol, polyvinylpyrrolidone, polyurethanes and / or urea urethane resins, and particularly preferably selected from urea urethane resins.

[0041] The urea urethane resin used as a thickener by component (B) of the preferred method according to the present invention for providing a colloidal aqueous solution starting from an aqueous dispersion is a mixture of polymer compounds resulting from the reaction of polyvalent isocyanates with polyols and mono- and / or diamines. In preferred embodiments, the urea urethane resin is preferably obtained from polyhydric isocyanates selected from 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2(4),4-trimethyl-1,6-hexamethylene diisocyanate, 1,10-decamethylene diisocyanate, 1,4-cyclohexylene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate and mixtures thereof, p- and m-xylylene diisocyanate, and 4-4'-diisocyanatodicyclohexylmethane, and particularly preferably from 2,4-toluene diisocyanate and / or m-xylylene diisocyanate. In a particularly preferred embodiment, the urea urethane resin is obtained from a polyol selected from polyoxyalkylenediol, particularly preferably polyoxyethylene glycol, wherein the polyoxyethylene glycol consists of preferably at least 6, particularly preferably at least 8, particularly more preferably at least 10, but preferably less than 26, and particularly preferably less than 23 oxyalkylene units.

[0042] A urea urethane resin that is particularly suitable and therefore preferred according to the present invention can be obtained by first reacting a diisocyanate, such as toluene-2,4-diisocyanate, with a polyol, such as polyethylene glycol, to form an NCO-terminated urethane prepolymer, followed by further reaction with a primary monoamine and / or primary diamine, such as m-xylylenediamine. A urea urethane resin having neither free nor blocked isocyanate groups is particularly preferred. Such a urea urethane resin, as a component of an aqueous dispersion in which a colloidal aqueous solution of the method according to the present invention can be obtained by dilution, promotes the formation of loose aggregates of primary particles, which are stabilized in the aqueous phase and protected from further aggregation to the extent that sedimentation of particulate components in the aqueous dispersion is largely prevented. To further enhance this property profile, a urea urethane resin having neither free or blocked isocyanate groups nor terminal amine groups is preferably used as component (B). Therefore, in preferred embodiments, the thickener, component (B), which is a urea urethane resin, in any case has an amine value of less than 8 mg KOH / g, particularly preferably less than 5 mg KOH / g, and particularly more preferably less than 2 mg KOH / g, determined according to the method described above for the organic polymer compound (A2). Since the thickener is substantially dissolved in the aqueous phase, it can be assigned to the non-particulate components of the aqueous dispersion, and component (A2) is substantially bound to the particulate components (A), but the aqueous dispersion is preferred to provide an activated colloidal aqueous solution in which the total polymer organic compound in the non-particulate components has an amine value of preferably less than 16 mg KOH / g, particularly preferably less than 10 mg KOH / g, and particularly more preferably less than 4 mg KOH / g. The urea urethane resin is even more preferably having a hydroxyl value in the range of 10 to 100 mg KOH / g, particularly preferably in the range of 20 to 60 mg KOH / g, determined according to Method A of European Pharmacopoeia 9.0 01 / 2008:20503.With respect to molecular weight, a weight-average molar mass of urea urethane resin in the range of 1000 to 10000 g / mol, preferably in the range of 2000 to 6000 g / mol, is advantageous according to the present invention, and therefore, in any case, it is preferable to determine it experimentally, as described above in relation to the definition of polymer compounds according to the present invention.

[0043] When no auxiliary agents are added, the pH of the dispersion for providing the activated colloidal aqueous solution of the method according to the present invention is typically in the range of 6.0 to 9.0, and therefore such a pH range is preferred according to the present invention. However, for compatibility with actual ordinary alkaline colloidal aqueous solutions in the activation step, it is advantageous for the pH of the aqueous dispersion to be greater than 7.2 as needed, and particularly preferably greater than 8.0, as a result of adding compounds that react in an alkaline manner. Since some polyvalent metal cations have amphoteric properties and can therefore be detached from particulate components at higher pH values, the alkalinity of the aqueous dispersion according to the present invention is ideally limited, and as a result, the pH of the aqueous dispersion is preferably less than 10, and particularly preferably less than 9.0.

[0044] The above-mentioned aqueous dispersion for providing a colloidal aqueous solution preferably includes, as part thereof, i) To provide a pigment paste, grind 10 parts by mass of an inorganic particulate compound (A1) together with 0.5 to 2 parts by mass of a polymeric organic compound (A2) in the presence of 4 to 7 parts by mass of water, dilute 1000 times with water, for example using Zetasizer® Nano ZS, Malvern Panalytical GmbH, and then grind until a D50 value of less than 1 μm is reached as determined by dynamic light scattering; ii) The pigment paste is mixed with an amount of water, preferably deionized water (κ < 1 μS cm), such that it contains at least 5% by weight of dispersed particulate components (A) and a thickener (B) that has a maximum kinematic viscosity of at least 1000 Pa·s at a temperature of 25°C in the shear rate range of 0.001 to 0.25 per second. -1 ) or diluting with tap water; and iii) It can be obtained by using a compound that reacts in an alkaline environment and setting the pH to a range of 7.2 to 10.0. Preferred embodiments of the dispersion are similarly obtained by selecting the corresponding components (A1), (A2), and (A) in any case as needed or in the required amounts, as described in relation to the colloidal aqueous solution.

[0045] The aqueous dispersion may also contain auxiliary agents selected from, for example, preservatives, wetting agents, and defoaming agents, which are included in amounts necessary for the relevant function. The content of auxiliary agents in the non-particulate components that are neither thickeners nor compounds that react in an alkaline manner, particularly preferably other compounds, is preferably less than 1% by weight. In the context of the present invention, compounds that react in an alkaline manner are water-soluble (water solubility: κ < 1 μS cm). -1 (At least 10g per 1kg of water), and in the first protonation step, a pK of over 8.0 B It has a value.

[0046] When the treatment of a metallic material selected from zinc, iron, or aluminum is referred to in the context of the methods according to the present invention, all materials containing more than 50 at% of the relevant elements are included. Pre-treatment for corrosion protection always relates to the surface of the material or component. The material may be a uniform material or coating. According to the present invention, a galvanized steel grade consists of both material steel and material zinc, and it is possible to expose the surface of iron at the cutting edges and cylindrical grinding points of an automobile body made of galvanized steel, in which case, according to the present invention, a pre-treatment of the material iron is present.

[0047] The components processed according to the present invention can be three-dimensional structures of any shape and design derived from the manufacturing process, including in particular semi-finished products such as strips, metal sheets, rods, and pipes, and composite structures assembled from said semi-finished products, the semi-finished products being interconnected, preferably by bonding, welding and / or flanging, to form the composite structure.

[0048] A rinsing step may be included between activation (i) and phosphate treatment (ii) to reduce the carryover of most of the alkaline components to the acidic phosphate treatment; however, it is preferable to omit the rinsing step to fully maintain the activation performance. The rinsing step is used solely to completely or partially remove soluble residues, particles, and active components carried over from the components being treated by adhering to components from the previous wet chemical treatment step, without containing metallic or metalloid active components, and the metallic or metalloid active components are already consumed by simply bringing the metallic surface of the components into contact with the rinsing solution and are contained in the rinsing solution itself. For example, the rinsing solution may simply be tap water or deionized water, or, if necessary, a rinsing solution containing surfactant compounds to improve wettability.

[0049] For the purpose of activating the metal material, which is layer-forming phosphate treatment and formation of a semi-crystalline coating, the phosphate treatment in step (ii) is preferably carried out by contacting the surface with an acidic aqueous composition containing 5 to 50 g / kg of phosphate dissolved in water, calculated as PO4, and preferably further containing at least one source of free fluoride. According to the present invention, the amount of phosphate ions is calculated as PO4 and includes orthophosphate and anions of the salt of orthophosphate dissolved in water.

[0050] In a preferred embodiment of the present invention, the subsequent phosphate treatment is a zinc phosphate treatment, and the phosphate treatment in step (ii) is based on an acidic aqueous composition containing 0.3 to 3 g / kg of zinc ions, preferably an acidic aqueous composition containing 5 to 50 g / L of phosphate ions, 0.3 to 3 g / L of zinc ions, and a certain amount of free fluoride.

[0051] The free fluoride ion source is desired to form a layer on all metallic materials selected from zinc, iron, or aluminum, and is essential to the layer-forming zinc phosphate treatment process, for example, insofar as it is required for the zinc phosphate treatment of automobile bodies, which are also made at least partially of aluminum. When a phosphate coating is provided on all surfaces of the metallic material component, the amount of particulate components in the activation must often be adjusted to match the amount of free fluoride required for layer formation in the zinc phosphate treatment. In the method according to the present invention, which is based on activation (i) followed by zinc phosphate treatment (ii), where the pre-treated component is made from metallic materials of zinc and iron, particularly steel, it is advantageous that the amount of closed, defect-free phosphate coating in the acidic aqueous composition is at least 0.5 mmol / kg relative to the amount of free fluoride. When the component is also made from the metallic material aluminum, and a closed phosphate coating is also provided on its surface, it is also preferable in the method according to the present invention that the amount of free fluoride in the acidic aqueous composition is at least 2 mmol / kg. The concentration of free fluoride should not exceed a value at which the phosphate coating has adhesion that can be easily wiped away, since this adhesion cannot be avoided even if the amount of particulate matter in the colloidal aqueous solution of the activation increases disproportionately. Therefore, in the method according to the present invention based on activation (i) followed by zinc phosphate treatment (ii), it is also economically advantageous and therefore preferable that the concentration of free fluoride in the acidic aqueous composition of the zinc phosphate treatment be less than 15 mmol / kg, particularly preferably less than 10 mmol / kg, and particularly more preferably less than 8 mmol / kg.

[0052] The amount of free fluoride can be determined by potential difference measurement with a fluoride-sensitive measuring electrode at 20°C in the relevant acidic aqueous composition after calibration with a fluoride-containing buffer without pH buffering. Suitable sources of free fluoride are hydrofluoric acid and its water-soluble salts, such as ammonium bifluoride and sodium fluoride, and complex fluorides of the elements Zr, Ti and / or Si, especially complex fluorides of the element Si. Thus, in the phosphate treatment process according to the invention, the source of free fluoride is preferably selected from hydrofluoric acid and its water-soluble salts and / or complex fluorides of the elements Zr, Ti and / or Si. The salts of hydrofluoric acid are water-soluble within the meaning of the invention if their solubility in deionized water (κ < 1 μS cm -1 ) at 60°C, calculated as F, is at least 1 g / L.

[0053] In such a method according to the present invention, in which zinc phosphate treatment is performed in step (ii) to suppress what is known as "pin-holing" on the surface of a metallic material made of zinc, it is preferable that the free fluoride source is at least partially selected from complex fluorides of element Si, particularly hexafluorosilicic acid and its salts. The term pin-holing is understood by those skilled in the art of phosphate treatment to mean the phenomenon of localized deposition of amorphous white zinc phosphate in other crystalline phosphate layers on a treated zinc surface or a treated zinc-plated or alloy-zinc-plated steel surface. Pin-holing in this case is caused by a locally increased acid cleaning rate of the substrate. The occurrence of pinholes should be avoided as much as possible in practice, as such point defects in phosphate treatment can be the starting point for corrosive peeling of the organic coating system subsequently applied. In this regard, the concentration of silicon in its aqueous form in the acidic aqueous composition of the zinc phosphate treatment in step (ii) is at least 0.5 mmol / kg, particularly preferably at least 1 mmol / kg, particularly more preferably at least 2 mmol / kg, but preferably less than 15 mmol / kg, particularly preferably less than 12 mmol / kg, particularly more preferably less than 10 mmol / kg, and very preferably less than 8 mmol / kg. The upper limit of silicon concentration is preferable because, above these values, a phosphate coating with mostly loose adhesion is preferred, which cannot be avoided even by an unbalanced large amount of particulate components in the colloidal aqueous solution of the activation step. The concentration of silicon in its aqueous form in the acidic aqueous composition can be determined by atomic emission spectrometry (ICP-OES) of the filtrate of membrane filtration of the acidic aqueous composition performed using a membrane with a nominal pore size of 0.2 μm.

[0054] Regarding the interaction between activation and zinc phosphate treatment, it has been found that the content of particulate components contributing to activation needs to be matched to the amount of free fluoride and silicon in the zinc phosphate treatment to ensure that a larger amount of free fluoride for layer-forming phosphate treatment does not adversely affect layer formation for components containing aluminum as a metallic material in the phosphate treatment bath, which is very important for a certain quality of phosphate coating, especially when pre-treating a large number of components. In this regard, the method according to the present invention, in which a series of components are pre-treated, is preferred, and this series of components includes components made of at least partially zinc and aluminum materials, and the series of components are first activated (i) and then treated with zinc phosphate (ii) in a series of method steps, the activation in method step (i) is carried out by contacting the components with the above-mentioned colloidal aqueous solution, which in a preferred embodiment can be obtained as the above-mentioned aqueous dispersion diluted 20 to 100,000 times, and the zinc phosphate treatment in method step (ii) is (a) 5-50 g / l of phosphate ions, (b) 0.3 to 3 g / l of zinc ions, and (c) This can be done by contact with an acidic aqueous composition containing at least one free fluoride source, The quotient (mmol / kg) of the concentration of phosphate in the inorganic particulate components of the activated colloidal aqueous solution, based on PO4, to the sum of the concentrations of free fluoride and silicon in the acidic aqueous composition treated with zinc phosphate in each case, is greater than 0.2, preferably greater than 0.3, and particularly preferably greater than 0.4 in all cases.

[0055] To the extent that the zinc phosphate treatment in step (ii) is referred to in the context of a second aspect of the present invention, the preferred pH of the acidic aqueous composition resulting from the zinc phosphate treatment is greater than 2.5, particularly preferably greater than 2.7, but preferably less than 3.5, and particularly preferably less than 3.3. The free acid content at points in the acidic aqueous composition for the zinc phosphate treatment in step (ii) is preferably at least 0.4, preferably 3.0 or less, and particularly preferably 2.0 or less. The free acid content at points is determined by diluting a sample volume of 10 ml of the acidic aqueous composition to 50 ml and titrating it to pH 3.6 with a 0.1 N sodium hydroxide solution. The amount of mL of sodium hydroxide solution consumed indicates the number of points of free acid.

[0056] Conventional additions of additives for zinc phosphate treatment can also be carried out in the context of the present invention so that the acidic aqueous composition of step (ii) may further contain conventional accelerators such as hydrogen peroxide, nitrite, hydroxylamine, nitroguanidine and / or N-methylmorpholine-N-oxide, as well as cations of metallic manganese, calcium and / or iron in the form of water-soluble salts that have a beneficial effect on layer formation. In preferred embodiments for environmental and hygienic reasons, less than 10 ppm of nickel and / or cobalt ions in total is contained in the acidic aqueous composition of the zinc phosphate treatment in step (ii).

[0057] In the method according to the present invention, a good coating primer for subsequent dipping coatings is produced during the process of applying a substantially organic cover layer. Accordingly, in a preferred embodiment of the method according to the present invention, dipping coatings, particularly preferably electrocoatings, and especially more preferably cathode electrocoatings, are performed following a zinc phosphate treatment with or without an intermediate rinsing and / or drying step, or preferably with a rinsing step but without a drying step, which preferably contains a dispersion resin comprising an amine-modified polyepoxide, in addition to a water-soluble or water-dispersible salt of yttrium and / or bismuth. [Examples]

[0058] Below, we show the characteristics of the activation, including tap water for subsequent zinc phosphate treatment, with respect to the phosphate layer weight and corrosion protection results achieved under the same conditions.

[0059] <Preparation of Pigment Paste> To prepare a pigment paste for obtaining an activation dispersion, 15 parts by mass of Edaplan® 490 (Muenzing Chemie GmbH) was added as a dispersant, along with 25 parts by mass of completely deionized water (κ < 1 μS cm). -1 After pre-dispersion, the mixture was combined with 60 parts by mass of zinc phosphate of quality level PZ 20. This phase was transferred to a KDL-type Dyno®-Mill bead mill, and the zinc phosphate particles were continuously ground for 2 hours (grinding parameters: 75% bead filling level, 2000 rpm, 20 L volume flow rate / hour, temperature of ground material 40-45°C). The result, determined using a Malvern Zetasizer Nano ZS, was an average particle size of approximately 0.35 μm.

[0060] <Preparation of dispersion for activation> Next, approximately 64 parts by mass of completely deionized water (κ < 1 μS cm) -1 2.5 parts by mass of a urea urethane resin solution containing 40% by weight of a resin based on amine-modified prepolymers of TDI / XDI and PEG-16 (amine value < 1 mg KOH / g; hydroxyl value approximately 40 mg KOH / g) was added as a thickener, homogenized, and adjusted to pH 9 using a 10% sodium hydroxide solution. Then, approximately 33 parts by mass of pigment paste was added while stirring, and the pH was adjusted to pH 9 using a 1% by weight NaOH solution, and the mixture was stirred until complete homogenization was achieved.

[0061] <Preparation of colloidal aqueous solution for activation in zinc phosphate treatment> In a 5L beaker, add 5 liters A) Completely deionized water (κ < 1 μS cm) containing 5 grams of an additive solution consisting of 10.3% by weight potassium pyrophosphate and 25.3% by weight potassium phosphate. -1A mixture was prepared, and while stirring, the pH was adjusted to 10.5 using phosphoric acid, and 7.5 grams of the above dispersion was added. Next, while stirring, the pH was adjusted to 10.5 using a 1% sodium hydroxide solution. B) Tap water from Düsseldorf (dissolved alkaline earth metal ions: 14 mg / L Mg; 96 mg / L Ca; κ = 726 μS cm) -1 A solution was prepared, and 7.5 grams of the above dispersion was added. Then, the pH was adjusted to 8.0 using a 1% sodium hydroxide solution while stirring.

[0062] <Sequence of zinc phosphate treatment method> For layer-forming phosphate treatment by activation using a colloidal aqueous solution, the cold-rolled steel (CRS) sheet, hot-dip galvanized steel (HDG) sheet, and aluminum (AA6014) sheet were as follows: a) First, alkaline washing is performed by immersion for 5 minutes in a degreasing bath containing 4% by weight of Bonderite® C-AK 1565 A and 0.6% by weight of Bonderite® C-AD 1561, respectively, available from Henkel AG&Co KGaA, while stirring in Düsseldorf tap water (pH: 10.2-10.9; 55°C); b) In all cases, Düsseldorf city tap water is used for approximately 30 seconds, followed by completely deionized water (κ < 1 μS cm). -1 ) to be used for rinsing; c) Contact with activating solution A while wet with water, or, according to the present invention, contact with activating solution B by immersion for 60 seconds; d) Immediately afterward, without performing a further rinsing step, completely deionize the water (κ < 1 μS cm). -1The sample is then immersed for 3 minutes at 52°C while stirring in a hydroxylamine-enhanced phosphate treatment bath containing 4.6% by weight of Bonderite® M-ZN 1994, 0.8% by weight of Bonderite® M-AD 565, 0.24% by weight of Bonderite® M-AD 338, and 0.38% by weight of Bonderite® M-AD 110 (each available from Henkel AG & Co KGaA), with a free acid content of 0.9–1.4 points (titrated to pH 3.6), a total acid content of 25–30 points (titrated to pH 8.5), and a free fluoride content of approximately 150 mg / kg; e) Fully deionized water (κ<1μScm -1 ) subject to rinsing for approximately 30 seconds; f) A layer of electrocoating with Cathoguard® 800 (BASF SE) approximately 20 μm thick was applied, and then cured at 180°C for 35 minutes.

[0063] Table 1 summarizes the layer weight and the results of zinc phosphate treatment after aging in corrosion tests. Compared to the method using deionized water (A), it is clear that activation using tap water (B) results in a homogeneous, closed zinc phosphate coating with lower layer weight and improved corrosion protection.

[0064] [Table 1] Preferred embodiments of the present invention include the following: [1] A method for pretreatment of a metallic material selected from zinc, iron, or aluminum, or a component consisting at least partially of such a metallic material, wherein the metallic material or the component is subjected to, in a series of method steps, first activation (i), then phosphate treatment (ii), particularly zinc phosphate treatment, wherein the activation in method step (i) is carried out by contacting the metallic material or the component with a colloidal aqueous solution, the colloidal aqueous solution being a solution of dispersed particulate components (a), (a1) at least one particulate inorganic compound comprising a phosphate of a polyvalent metal cation at least partially selected from hopeite, phosphophyllite, scholzite and / or halolite, and (a2) Contains at least one polymeric organic compound which is at least partially composed of styrene and / or an α-olefin having 5 or fewer carbon atoms, and is further composed of maleic acid, its anhydride and / or its imide, and which further contains polyoxyalkylene units, The colloidal aqueous solution contains at least 0.5 mmol / L of alkaline earth metal ions dissolved in water, and the method is as follows. [2] The method according to [1], characterized in that the colloidal aqueous solution contains alkaline earth metal ions dissolved in water at a concentration of at least 1.0 mmol / L, preferably at least 1.5 mmol / L, but preferably 10 mmol / L or less. [3] The method according to [1] or [2], characterized in that the content of the condensed phosphate dissolved in water in the colloidal aqueous solution is less than 0.25, preferably less than 0.20, particularly preferably less than 0.15, and very preferably less than 0.10, based on the phosphate content of the at least one particulate compound based on element P in all cases. [4] The method according to any one of [1] to [3], characterized in that the colloidal aqueous solution contains alkaline earth metal ions dissolved in water at a concentration of at least 0.5 mmol / L, preferably at least 1.0 mmol / L, and particularly preferably at least 1.5 mmol / L, but at a concentration of 10 mmol / L or less. [5] The method according to [4], characterized in that the colloidal aqueous solution contains at least one complexing agent, preferably selected from α-hydroxycarboxylic acid, then preferably selected from gluconic acid, tartaric acid, glycolic acid, citric acid, tartaric acid, lactic acid, very preferably gluconic acid and / or organic phosphonic acid, then preferably selected from etidronic acid, aminotris(methylenephosphonic acid), aminotris(methylenephosphonic acid), phosphonobutane-1,2,4-tricarboxylic acid, diethylenetriaminepenta(methylenephosphonic acid), hexamethylenediaminetetra(methylenephosphonic acid) and / or hydroxyphosphonoacetic acid, and particularly preferably selected from etidronic acid. [6] The method according to [5], characterized in that the amount of the complexing agent in the colloidal aqueous solution is 2 times or less the molar amount of the alkaline earth metal ions, preferably 1.5 times or less, and particularly preferably equimolar or less the amount of the alkaline earth metal ions. [7] The method according to any one of [1] to [6], characterized in that the colloidal aqueous solution in activation (i) has an alkaline pH, preferably greater than 8.0, particularly preferably greater than 9.0, but preferably less than 11.0. [8] The at least one particulate inorganic compound (a1) contains, PO 4 The method according to any one of [1] to [7], characterized in that the phosphate content, calculated as such, is preferably at least 25% by weight, particularly preferably at least 35% by weight, particularly more preferably at least 40% by weight, and very preferably at least 45% by weight, based on the dispersed inorganic particulate components of the colloidal aqueous solution. [9] The method according to any one of [1] to [8], characterized in that the polymer organic compound (a2) in the colloidal aqueous solution contains polyoxyalkylene units in its side chains, and the content of polyoxyalkylene units in the total polymer organic compound (a2) is preferably at least 40% by weight, particularly preferably at least 50% by weight, but particularly preferably not exceeding 70% by weight.

[10] The method according to any one of [1] to [9], wherein the organic polymer compound (a2) of the colloidal aqueous solution is preferably selected from pyridine, imidazole, imidazoline, morpholine, pyrrole and / or pyrrolidone units, particularly preferably from imidazole and / or imidazoline units, and particularly more preferably from imidazole units, each of which is preferably part of the side chain of the polymer organic compound (a2), and also includes N-heterocyclic units, which are aliphatically connected to the main chain, then preferably via at least three carbon atoms, particularly preferably, such that the polyoxyalkylene units of the polymer organic compound (a2) are at least partially end-capped by N-heterocyclic units.

[11] The method according to any one of [1] to

[10] , characterized in that the colloidal aqueous solution contains as a further component b) at least one thickener selected from urea urethane resins having an amine value of preferably less than 8 mg KOH / g, particularly preferably less than 5 mg KOH / g, and very preferably less than 2 mg KOH / g.

[12] The method according to any one of [1] to

[11] , characterized in that the particulate components of the colloidal aqueous solution and the entire polymer organic compound based on the particulate components constitute at least 3% by weight, preferably at least 6% by weight, but preferably not exceeding 15% by weight.

[13] The method according to any one of [1] to

[12] , characterized in that the colloidal aqueous solution has a D50 value of less than 1 μm, preferably less than 0.4 μm.

[14] The method according to any one of [1] to

[13] , characterized in that the content of the particulate components in the colloidal aqueous solution is at least 0.05 g / kg, preferably at least 0.1 g / kg, particularly preferably at least 0.2 g / kg, but preferably 10 g / kg or less, particularly preferably 2 g / kg or less, based on the colloidal aqueous solution.

[15] The colloidal aqueous solution is obtained as an aqueous dispersion diluted 20 to 100,000 times, -Based on the aqueous dispersion, a dispersed particulate component (A) comprising at least 5% by weight, (A1) At least one particulate inorganic compound comprising a phosphate of a polyvalent metal cation at least partially selected from hopeite, phosphophyllite, scholzite and / or halolite, (A2) A dispersed particulate component (A) comprising at least one polymeric organic compound which is at least partially composed of styrene and / or an α-olefin having 5 or fewer carbon atoms, and which is at least partially composed of maleic acid, its anhydride and / or its imide, and further comprises polyoxyalkylene units, and -Optionally, comprising at least one thickener (B) selected from urea urethane resins having an amine value of less than 8 mg KOH / g, more preferably less than 5 mg KOH / g, and more preferably less than 2 mg KOH / g, The method according to any one of [1] to

[14] , characterized in that the dilution is carried out using water containing at least 0.5 mmol / L, preferably at least 1 mmol / L, and particularly preferably at least 1.5 mmol / L of alkaline earth metal ions dissolved in water.

[16] The phosphate treatment in step (ii) of the method is PO 4 The method according to any one of [1] to

[15] , characterized by being carried out by contact with an acidic aqueous composition containing 5 to 50 g / kg of phosphate dissolved in water, 0.3 to 3 g / kg of zinc ions, and an amount of free fluoride that can contain a total of less than 0.1 g / kg of nickel and cobalt ions.

Claims

1. A method for pretreatment of a metallic material selected from zinc, iron, or aluminum, or a component at least partially composed of such a metallic material, wherein the metallic material or the component is subjected to a sequential method step, first activation (i), then phosphate treatment (ii), wherein the activation in method step (i) is carried out by contacting the metallic material or the component with a colloidal aqueous solution having a pH greater than 8.0, the colloidal aqueous solution comprising a solution of dispersed particulate components (a), the dispersed particulate components (a) are (a1) at least one particulate inorganic compound comprising a phosphate of a polyvalent metal cation at least partially selected from hopeite, phosphophyllite, scholzite and / or halolite, and (a2) A polymeric organic compound comprising at least partially styrene and / or an α-olefin having 5 or fewer carbon atoms, and further comprising maleic acid, its anhydride and / or its imide, and further containing polyoxyalkylene units in their side chains, wherein the content of polyoxyalkylene units in the whole polymeric organic compound is at least 40% by weight but 70% by weight or less, at least one polymeric organic compound It contains, The colloidal aqueous solution contains at least 0.5 mmol / L of alkaline earth metal ions dissolved in water, in a method.

2. The method according to claim 1, characterized in that, in the colloidal aqueous solution, the content of condensed phosphate dissolved in water is less than 0.25 in all cases, based on the phosphate content of the at least one particulate inorganic compound based on element P.

3. The method according to claim 1 or 2, characterized in that the colloidal aqueous solution contains at least 1.0 mmol / L of alkaline earth metal ions dissolved in water, but not exceeding 10 mmol / L.

4. The method according to claim 3, characterized in that the colloidal aqueous solution contains at least one complexing agent.

5. The method according to claim 4, characterized in that the amount of the complexing agent in the colloidal aqueous solution is twice or less the molar amount of alkaline earth metal ions.

6. The at least one particulate inorganic compound (a1) contains PO ４ The method according to any one of claims 1 to 5, characterized in that the phosphate content, calculated as such, is at least 25% by weight, based on the dispersed particulate component (a) of the colloidal aqueous solution.

7. The method according to any one of claims 1 to 6, characterized in that the organic polymer compound (a2) in the colloidal aqueous solution also contains an N-heterocyclic unit.

8. The method according to any one of claims 1 to 7, characterized in that the colloidal aqueous solution contains at least one thickening agent as a further component b).

9. The method according to any one of claims 1 to 8, characterized in that, in the dispersed particulate component (a) of the colloidal aqueous solution, the total amount of the polymer organic compound based on the dispersed particulate component (a) is at least 3% by weight, but not exceeding 15% by weight.

10. The method according to any one of claims 1 to 9, characterized in that the colloidal aqueous solution has a D50 value of less than 1 μm.

11. The method according to any one of claims 1 to 10, characterized in that the content of the dispersed particulate component (a) in the colloidal aqueous solution is at least 0.05 g / kg, but 10 g / kg or less, based on the colloidal aqueous solution in any case.

12. The colloidal aqueous solution is obtained by diluting the aqueous dispersion 20 to 100,000 times, and the aqueous dispersion is - Based on the aqueous dispersion, at least 5% by weight of dispersed particulate components (A), (A1) At least one particulate inorganic compound comprising a phosphate of a polyvalent metal cation at least partially selected from hopeite, phosphophyllite, scholzite and / or halolite, (A2) A dispersed particulate component (A) comprising at least one polymeric organic compound which is at least partially composed of styrene and / or an α-olefin having 5 or fewer carbon atoms, and at least partially composed of maleic acid, its anhydride and / or its imide, and further comprising polyoxyalkylene units, wherein the polyoxyalkylene unit content in the whole polymeric organic compound is at least 40% by weight, and -Optionally, comprising at least one thickening agent (B), The method according to any one of claims 1 to 11, characterized in that the dilution is carried out using water containing at least 0.5 mmol / L of alkaline earth metal ions dissolved in water.

13. The phosphate treatment in step (ii) is PO ４ The method according to any one of claims 1 to 12, characterized by being carried out by contact with an acidic aqueous composition containing 5 to 50 g / kg of phosphate, 0.3 to 3 g / kg of zinc ions, and free fluoride dissolved in water, calculated as follows.

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