Composition for phosphate treatment of iron surfaces and method of use thereof

Abstract

The present invention relates to an acidic aqueous composition which is free or substantially free of both fluoride anions and nickel cations and which comprises at least components a1) to a5) which are different from one another, namely phosphate anions as a1), nitrate anions as a2), zinc cations as a3), copper cations as a4), and magnesium cations as a5), a concentrate for producing said composition by dilution with water, a method for using said composition for at least partially phosphating an iron surface of a substrate, a method for phosphating at least one iron surface of at least one substrate, which method comprises at least step 1), i.e., contacting at least one iron surface at least partially with the aqueous acidic composition for phosphating at least one surface of the present invention, a substrate having at least one phosphate-treated surface obtainable by said phosphating method, and a method for cold-forming said substrate having at least one iron surface, which method comprises subjecting said substrate having at least one phosphate-treated surface to a cold-forming process.

Description

[Technical Field]

[0001] The present invention relates to an acidic aqueous composition that is free or substantially free of both fluoride anions and nickel cations and that can be used as a phosphating composition, particularly for substrates having iron surfaces, and to a method for phosphating such surfaces of a substrate, the method comprising at least the step of contacting at least one iron surface at least partially with the aqueous acidic composition of the present invention. [Background technology]

[0002] The use of phosphate coatings on metal surfaces is known in the prior art. The coatings serve to protect the metal surface against corrosion and also function as adhesion promoters for subsequent coating layers. Such phosphate coatings are used, for example, in the automotive industry, but also in other industries. For example, phosphate coatings are often applied to substrates, such as iron substrates, as an initial protective layer, which are then subjected to a cold-forming process to convert them into an article having a desired shape. To minimize the degree of deformation during this process, the phosphate coating is often further coated with a lubricant, such as soap or oil or a polymer composition.

[0003] In the automotive industry, in particular, phosphate coatings are often applied with nickel-containing phosphating compositions to ensure sufficient electrical conductivity of subsequent electrodeposition coatings applied thereon. However, due to their high toxicity and environmental toxicity, the use of nickel ions is no longer desirable, and their content should therefore be avoided or at least reduced as much as possible to avoid any contamination, for example, of the sludge formed during the phosphating process. Furthermore, known methods using compositions containing nickel ions often require relatively long treatment times (e.g., >7 minutes) and relatively high bath temperatures (e.g., >60°C) generated with the composition, both of which are disadvantageous from an economic and ecological standpoint. Furthermore, unwanted deposits are often observed on heating pipes. The use of nickel-free or low-nickel phosphating compositions is also known in the prior art, for example, from WO 2004 / 099468 A1 and EP 0613964 A1.

[0004] EP 0613964 A1 relates to a method comprising applying an acidic aqueous phosphate solution to an iron-based material, the acidic aqueous phosphate solution being free of nitrogen compounds containing nitrate ions, particularly zinc ions, magnesium ions, phosphate ions, fluoroborate ions, and chlorate ions, and having a Zn:Mg:BF4 mass ratio of 1:0.15:0.15 to 1:1:1. The composition of EP 0613964 A1 therefore necessarily contains fluoride ions, at least in the form of fluoroborate. EP 0613964 A1 aims to facilitate the cold working of iron-based materials by a method that does not create wastewater problems and results in the formation of a firmly adherent coating thick enough for cold working. However, disadvantages of the method according to EP 0613964 A1 include the undesirable relatively high amount of sludge formed during the method and the relatively hard nature of the sludge, which is disadvantageous in terms of the subsequent need for and means for its disposal. Furthermore, the process of EP 0 613 964 A1 necessarily involves the use of fluoride ions, which are disadvantageous / undesirable, especially from an ecological point of view.

[0005] WO 2004 / 099468 A1 relates to a method for coating the surface of a metal object with a composition containing an aqueous acidic phosphate, the composition containing, inter alia, phosphate ions, zinc ions, optionally magnesium ions, and optionally calcium ions, with at least 0.1 g / L of calcium or / and magnesium ions, optionally complex fluorides MeF4 or / and MeF6 (Me=B, Si, Ti, Hf, or / and Zr), and optionally fluoride ions present, with the proviso that the total amount of complex fluorides and fluoride ions is at least 0.1 g / L, and the composition itself. Thus, the composition of WO 2004 / 099468 A1 necessarily contains fluoride ions themselves and / or fluoride ions in the form of complex fluorides. WO2004 / 099468A1 aims to provide a method for phosphate-treating the surface of metal objects, which method is suitable for forming a cold-formed phosphate layer, and can significantly reduce the amount of sludge formed during phosphate-treating, without impairing its usefulness and industrial applicability.The disadvantage of the method according to WO2004 / 099468A1 is that although the amount of sludge formed is reduced, the sludge formed is relatively hard, especially when calcium ions are present in the composition, which is disadvantageous from the viewpoint of the need for subsequent disposal and the means of said disposal.In addition, the method of WO2004 / 099468A1 necessarily uses fluoride ions, which is particularly disadvantageous / undesirable from an ecological viewpoint.

[0006] It is therefore necessary to provide an efficient method for the phosphating of iron substrates which does not result in the drawbacks observed when using conventional phosphating compositions known in the prior art, in particular phosphating compositions containing nickel cations and / or fluoride. In particular, it is necessary to provide an efficient method for the phosphating of iron substrates which can be carried out at relatively low temperatures, which reduces sludge formation to the lowest possible extent, and which sludge is as soft as possible. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] WO2004 / 099468A1 [Patent Document 2] EP0613964A1 Summary of the Invention [Problem to be solved by the invention]

[0008] It is therefore an object of the present invention to provide an efficient method for the phosphating of iron substrates which does not result in the drawbacks observed when using conventional phosphating compositions known from the prior art, in particular phosphating compositions containing nickel cations and / or fluoride. In particular, it is an object to provide an efficient method for the phosphating of iron substrates which can be carried out at relatively low temperatures, which reduces sludge formation to the lowest possible extent, and which sludge is as soft as possible. [Means for solving the problem]

[0009] solution This object has been solved by the subject matter of the present claims and the preferred embodiments thereof disclosed herein, ie the subject matter described herein.

[0010] A first subject of the present invention is a composition comprising at least components a1) to a5), which are free or substantially free of both fluoride anions and nickel cations and which are different from one another, namely: phosphate anions as component a1), nitrate anion as component a2), As component a3), zinc cations, preferably in an amount ranging from 5 to 60 g / L, calculated as the metal, and copper cations as component a4); Including, The acidic aqueous composition further comprises magnesium cations as component a5).

[0011] A further subject of the invention is a concentrate for producing the compositions according to the invention by dilution with water.

[0012] A further subject of the present invention is the use of the composition of the present invention for at least partially phosphating the iron surface of a substrate.

[0013] A further subject of the present invention is a method for phosphating at least one iron surface of at least one substrate, comprising at least step 1) and optionally at least one of steps 2) and 3), namely 1) at least partially contacting at least one iron surface of at least one substrate with the aqueous acidic composition of the present invention for phosphating at least one surface; 2) optionally rinsing the phosphate-treated surface obtained after step 1) with water; and 3) Optionally, drying the phosphate-treated surface obtained after step 1) or optional step 2). The method includes:

[0014] A further subject of the present invention is a substrate having at least one phosphate-treated surface, which substrate can be obtained by the phosphating method of the present invention, the phosphate-treated surface preferably having a coating weight of 3 to 15 g / m 3 , more preferably 4 to 12 g / m 2 , and even more preferably 5 to 10 g / m 3 The surface has a phosphate layer having a thickness in the range of 1000 nm to 1000 nm.

[0015] A further subject of the present invention is a method for cold-forming a substrate having at least one iron surface, characterized in that it comprises a step of subjecting an inventive substrate having at least one phosphate-treated surface, or an inventive substrate having at least one phosphate-treated surface obtained from an inventive phosphating method, to a cold-forming process, preferably by drawing, in which, prior to said cold-forming process, the substrate is optionally subjected to further steps and at least one lubricant is applied at least partially onto the phosphate-treated surface of the substrate.

[0016] In particular, it has been found that the acidic aqueous composition of the present invention can be effectively used as a phosphating composition for phosphating the iron surface of a substrate. It has been found that by using the acidic aqueous composition of the present invention as a phosphating composition, sufficient pickling attack on the iron surface is achieved without the need to use any fluoride anions as an additional component, which is advantageous from both an environmental and economic perspective.

[0017] Surprisingly, it has been found that, in particular, the presence of magnesium cations in the composition allows the phosphating baths obtained from said compositions to be used at relatively low temperatures during the phosphating process, in particular temperatures as low as 55°C or 50°C, which is advantageous from both an ecological and an economical point of view. Furthermore, when only the aforementioned relatively low temperatures are used, less fouling of the heating pipes is observed with the phosphating baths obtained from the compositions of the invention. Even more surprisingly, it has been found that, in particular, the presence of magnesium cations in the composition allows the contact time of the surface of the substrate to be phosphated with the phosphating bath obtained from said composition to be relatively short, in particular as short as 3 to 5 minutes, which is advantageous from both an ecological and an economical point of view.

[0018] Furthermore, it has been found, particularly surprisingly, that the presence of magnesium cations in the composition results in relatively low sludge formation during phosphating, particularly compared to prior art phosphating processes. It has been found that the volume of sludge can be reduced by at least 20% to up to 50% by volume compared to conventional phosphating processes. Furthermore, it has been found, even more surprisingly, that the reduced amount of sludge formed is relatively soft and therefore less hard, particularly compared to prior art phosphating processes. This is advantageous from both an ecological and economic standpoint, since it facilitates the subsequent sludge disposal process. The softer the sludge, the smaller its volume and the easier it is to dispose of. Furthermore, softer sludge is easier to remove from the heating pipes of the phosphating bath obtained from the composition of the present invention than harder sludge, because softer sludge can be removed, for example, simply by spraying it with compressed water. However, harder sludge requires more force and often cannot be cleaned without the use of acid.

[0019] Furthermore, it has surprisingly been found that the heating pipes of the phosphating baths obtained from the compositions of the present invention are free of, or at least significantly reduced, deposits, especially when compared with prior art phosphating processes. As outlined above, if small deposits are observed, these can be removed with compressed water alone, since the sludge deposits adhering to the pipes are made up of only soft sludge, and therefore no higher forces need to be used.

[0020] Furthermore, it has been found that the presence of magnesium cations in the composition allows the use of phosphating baths obtained from said compositions with stabilized S values ​​(acid numbers), so that there is no need to reduce these values ​​by adding suitable components, such as zinc carbonate, after bath preparation, as is often necessary in prior art phosphating processes. DETAILED DESCRIPTION OF THE INVENTION

[0021] The term "comprising" in the sense of the present invention, for example in relation to an aqueous acidic composition, preferably has the meaning "consisting of". For example, in relation to said composition, in addition to all the essential components present therein, i.e. water and components a1) to a5), one or more of the further optional components identified below may also be included in the composition. Every component may be present in each case in its preferred embodiment identified below.

[0022] The proportions and amounts by weight (% by weight) of any of the components set out below present in each of the aqueous acidic compositions add up to 100% by weight in each case, relative to the total weight of the aqueous acidic composition.

[0023] Aqueous acidic composition The first subject of the present invention is an acidic aqueous composition that is free or substantially free of both fluoride anions and nickel cations and that contains at least mutually different components a1) to a5), namely, phosphate anions as component a1), nitrate anions as component a2), zinc cations as component a3), and copper cations as component a4), and the composition further contains magnesium cations as component a5). This composition is suitable as a phosphating (zinc phosphating) composition, particularly for use on iron substrates. The terms "phosphating" and "phosphated" are used interchangeably herein.

[0024] The aqueous composition is acidic, i.e., has a lower pH value, preferably less than 6.5. Preferably, the composition has a pH value in the range of 0.5 to 6.5, more preferably 0.8 to 6.0, also more preferably 1.0 to 5.5 or 5.0, even more preferably 1.2 to 4.5 or 4.0, even more preferably 1.5 to 3.5 or 3.0, and most preferably 1.7 to 3.0 or 2.8. Preferably, the pH value is measured at the operating temperature of the phosphating bath prepared from the composition, more preferably at a temperature in the range of 40 to 70°C, even more preferably 45 to 60°C, and even more preferably 50 to 55°C. The pH value can be adjusted to alkaline using sodium hydroxide and / or potassium hydroxide and / or carbonates, and, in particular, if (further) acidity adjustment is required, can be adjusted by at least one inorganic acid, such as phosphoric acid.

[0025] The term "aqueous" in relation to an aqueous acidic composition preferably means, in the sense of the present invention, that the composition contains at least 50% by weight, preferably at least 60% by weight, more preferably at least 70% by weight, particularly at least 80% by weight, and most preferably at least 90% by weight of water, based on the total content of organic solvents and inorganic solvents, including water.Thus, an aqueous composition may contain at least one organic solvent in addition to water, but its amount is less than the amount of water present.Preferably, no organic solvent is present therein, or at least no organic solvent is intentionally added thereto.

[0026] Preferably, the aqueous acidic composition contains at least 50% by weight, preferably at least 60% by weight, more preferably at least 70% by weight, in particular at least 80% by weight and most preferably at least 90% by weight of water, these percentages by weight being in each case relative to its total weight.

[0027] Preferably, the aqueous acidic composition has a temperature in the range of 40 to 70°C, preferably 45 to 60°C, more preferably 50 to 55°C. The aqueous acidic composition can be converted into a bath (phosphating bath) containing this composition. Such a bath can thus be obtained from the composition. The acidic aqueous composition is preferably used as a dip-coating bath.

[0028] The acidic aqueous composition is free or substantially free of both fluoride anions and nickel cations. "Substantially free" in this context means that at least fluoride anions and / or nickel cations have not been intentionally added, but does not exclude that either of these may be present as impurities. "Fluoride anions" in this context also includes complex fluorides, such as tetrafluoroborate.

[0029] Preferably, the amount of fluoride anions present in the aqueous acidic composition does not exceed 2 g / L, more preferably does not exceed 1 g / L, even more preferably does not exceed 0.5 g / L, more preferably does not exceed 0.2 g / L, even more preferably does not exceed 0.1 g / L, and most preferably does not exceed 0.1 g / L, in each case calculated as F. Preferably, the amount of nickel cations present in the aqueous acidic composition does not exceed 2 g / L, more preferably does not exceed 1 g / L, even more preferably does not exceed 0.5 g / L, more preferably does not exceed 0.2 g / L, even more preferably does not exceed 0.1 g / L, and even more preferably does not exceed 0.1 g / L, and most preferably is at most 0.05 g / L, such as 0 or in the range of 0.001 to 0.05 g / L, in each case calculated as metal.

[0030] Preferably, the acidic aqueous composition is free or substantially free of boron, calculated as HBF. "Substantially free" in this context means that at least no boron has been intentionally added, but does not exclude that boron may be present as an impurity. Preferably, the amount of boron present in the aqueous acidic composition is no more than 2 g / L, more preferably no more than 1 g / L, even more preferably no more than 0.5 g / L, also more preferably no more than 0.2 g / L, still more preferably no more than 0.1 g / L, and most preferably less than 0.1 g / L, in each case calculated as HBF.

[0031] The content of nickel cations and any further cations and anions mentioned above and below can be monitored and measured by ICP-OES (Inductively Coupled Plasma Optical Emission Spectroscopy), which is described in the "Methods" section. However, the content of fluoride anions, if present, is measured by a fluoride electrode.

[0032] Preferably, the acidic aqueous composition is free or substantially free of calcium cations. "Substantially free" in this context means that at least no calcium cations have been intentionally added, but does not exclude that any of these may be present as impurities. Preferably, the amount of calcium cations present in the aqueous acidic composition does not exceed 1 g / L, calculated as the metal. The presence of such cations can adversely affect the softness of the sludge, potentially resulting in a sludge that is not particularly soft.

[0033] Preferably, the acidic aqueous composition is free or substantially free of chromium cations. "Substantially free" in this context means that at least no intentionally added chromium cations have been added, but does not exclude that such residues may be present as impurities. Preferably, the amount of chromium cations present in the aqueous acidic composition does not exceed 100 mg / L, calculated as the metal.

[0034] Component a1)—phosphate anion Preferably, the composition contains phosphate anions as component a1) in an amount in the range of 5 to 60 g / L, more preferably 6 to 50 g / L, even more preferably 7 to 48 g / L, also more preferably 8 to 40 g / L, still more preferably 9 to 35 g / L, even more preferably 10 to 30 g / L, also more preferably 12 to 25 g / L, and even more preferably 14 to 20 g / L, in each case calculated as P2O5.

[0035] Phosphate anions can be incorporated, for example, by using a suitable source of phosphate anions, such as phosphoric acid.

[0036] The phosphate anion can be present in condensed form (for example in the case of pyrophosphate (diphosphate)) and / or in non-condensed form. In other words, a mixture of both forms can also be present. The term "phosphate" also includes polyphosphates, for example tripolyphosphate. In each case, these partially and completely deprotonated forms are preferably also included.

[0037] Component a2) - Nitrate anion Preferably, the composition contains nitrate anions as component a2) in an amount ranging from 10 to 100 g / L, more preferably from 15 to 90 g / L, also more preferably from 20 to 80 g / L, even more preferably from 25 to 70 g / L, also more preferably from 30 to 60 g / L, and most preferably from 35 to 50 g / L, in each case calculated as NO3.

[0038] Preferably, the amount of nitrate anions present in the composition as component a2), expressed in g / L and calculated as NO3, is greater than the amount of phosphate anions present in the composition as component a1), expressed in g / L and calculated as PO5, and more preferably the relative mass ratio of nitrate anions, calculated as NO3, to phosphate anions, calculated as PO5, to each other is in the range of from 15:1 to 1.1:1, more preferably from 10:1 to 1.2:1, even more preferably from 7.5 to 1.3:1, still more preferably from 5.0 to 1.5:1, and even more preferably from 4:1 to 2:1.

[0039] Nitrate anions can be incorporated, for example, by using a suitable nitrate anion source, such as nitric acid.

[0040] Component a3) - Zinc cation Preferably, the composition contains zinc cations as component a3) in an amount ranging from 2.5 to 60 g / L, more preferably from 5 to 50 g / L, even more preferably from 7 to 40 g / L, even more preferably from 10 to 30 g / L, and even more preferably from 12 to 25 g / L, in each case calculated as metal. If the amount of zinc cations is too low, the formation of the phosphate layer may be hindered due to excessive pickling and / or the risk of precipitation of iron phosphate or iron zinc (ZnFe) phosphate. If the amount of zinc cations is too high, solubility problems may arise, which may also have a negative impact on precipitation.

[0041] Preferably, the amount of zinc cations present in the composition as component a3), expressed in g / L and calculated as metal, is greater than the amount of both magnesium cations present in the composition as component a5) and copper cations present in the composition as component a4), expressed in g / L and calculated as metal.

[0042] Preferably, the relative mass ratio of zinc cations and magnesium cations (component a5)) to one another, in each case calculated as the metal, is in the range of from 80:1 to 1.1:1, more preferably from 70:1 to 1.2:1, also more preferably from 60:1 to 1.5:1, even more preferably from 50:1 to 2:1, still more preferably from 40:1 to 3:1, also more preferably from 35:1 to 4:1, even more preferably from 30:1 to 5:1, even more preferably from 25:1 to 6:1, and most preferably from 22:1 to 8:1.

[0043] Zinc cations can be incorporated by using a suitable zinc cation source, for example, zinc carbonate, zinc oxide, zinc nitrate and / or zinc phosphate.

[0044] Component a4) - Copper cation Preferably, the composition contains copper cations as component a4) in an amount in the range of 0.5 to 100 ppm, more preferably 0.7 to 80 ppm, also more preferably 0.8 to 60 ppm, still more preferably 0.9 to 40 ppm, also more preferably 1 to 30 ppm, even more preferably 3 to 25 ppm, still more preferably 5 to 20 ppm and most preferably 7 to 18 ppm, in each case calculated as metal.

[0045] The presence of copper ions has been found to be advantageous as the presence of these ions has been observed to reduce pickling attack during the phosphating process, and in addition has been found to improve the appearance of the resulting coating.

[0046] Copper cations can be incorporated, for example, by using a suitable copper cation source, such as copper nitrate and / or copper hydroxycarbonate.

[0047] Component a5) - Magnesium cation Preferably, the composition contains magnesium cations as component a5) in an amount in the range of 0.1 to 6.0 g / L, more preferably 0.2 to 5.0 g / L, even more preferably 0.3 to 4.5 g / L, also more preferably 0.4 to 4.0 g / L, still more preferably 0.5 to 3.5 g / L, even more preferably 0.6 to 3.0 g / L, also more preferably 0.7 to 2.5 g / L, still more preferably 0.8 to 2.0 g / L and most preferably 1.0 to 2.0 g / L, in each case calculated as the metal.

[0048] Preferably, the amount of magnesium cations present in the composition as component a5) expressed in g / L, calculated as metal, is greater than the amount of copper cations present in the composition as component a4) expressed in g / L, calculated as metal.

[0049] Magnesium cations can be incorporated, for example, by using a suitable source of magnesium cations, such as magnesium oxide.

[0050] Optional components The composition may contain one or more additional cations and / or anions. Preferably, iron(II) cations are present in the composition in an amount ranging from 0.1 to 8 g / L, more preferably from 0.2 to 6 g / L, even more preferably from 0.3 to 4 g / L. Optionally, the composition may contain manganese cations, for example, in an amount ranging from 0 to 2 g / L. Preferably, the composition is free or substantially free of any trivalent cations, such as Al(III) cations. The amount of such cations is preferably less than 100 mg / L.

[0051] condensate Another subject of the present invention is a concentrate for producing the aqueous acidic composition of the present invention by dilution with water. Optionally, the pH value of the resulting composition can be adjusted by using at least one pH-adjusting additive. This concentrate therefore represents a masterbatch for producing the aqueous acidic composition of the present invention.

[0052] All preferred embodiments described above for the aqueous acidic composition of the present invention are also preferred embodiments of the condensate of the present invention.

[0053] The concentrate used to prepare the aqueous acidic composition typically contains the components of the aqueous acidic composition to be prepared in the desired proportions, but at higher concentrations. Such concentrate is diluted with water to the desired concentration of the components disclosed above to form the aqueous acidic composition. If necessary, the pH value of the aqueous acidic composition can be adjusted after dilution and as outlined above. Of course, any of the components of the aqueous acidic composition can be further added to the water used for dilution, or any of the components can be added after diluting the concentrate with water. However, it is preferred that the concentrate already contains all the necessary components.

[0054] Preferably, the concentrate is diluted with water in a mass ratio of 1:5000 to 1:10, more preferably 1:1000 to 1:10, most preferably 1:300 to 1:10, and even more preferably 1:150 to 1:50 to produce the aqueous acidic composition of the present invention.

[0055] Methods of using aqueous acidic compositions The aqueous acidic compositions of the present invention can be used to at least partially phosphate the iron surface of a substrate, and such methods of use are therefore a further subject of the present invention.

[0056] All preferred embodiments described above for the aqueous acidic composition of the invention and the condensate of the invention are also preferred embodiments of the method of use of the invention.

[0057] The substrate used has at least one iron surface. At least one region of said surface must therefore be iron. Preferably, the substrate itself is metallic, i.e. made of at least one metal and / or its alloy. The surface may consist of different regions containing different metals and / or their alloys. Preferably, all regions of the substrate, more preferably all surfaces, are iron. Even more preferably, the substrate itself is iron.

[0058] Preferably, at least one ferrous surface of the base metal is selected from the group consisting of steels, including cold-rolled steels and hot-rolled steels, and steel alloys, preferably steel alloys containing up to 5% by weight of alloying material elements such as Mn, Cr, B, etc.

[0059] As substrates it is possible to use, for example, strips, sheets, slugs, wires, wire coils, parts of more complex shape, sleeves, profiles, such as hollow or solid profiles, tubes, tube sections, discs, rods, bars or cylinders.

[0060] Phosphate Treatment Method A further subject of the present invention is a method for phosphating at least one iron surface of at least one substrate, the method comprising at least step 1) and, optionally, at least one of steps 2) and 3). The method may comprise one or more further optional additional steps, including steps carried out before step 1). Since the surface to be phosphating is iron, the phosphating process can be considered an "ironside process".

[0061] All preferred embodiments described above for the inventive aqueous acidic composition, the inventive condensate and the inventive method of use are also preferred embodiments of the inventive method, as well as for the substrate itself embodiments outlined above for the inventive method of use.

[0062] Optional steps performed before step 1) The at least one iron surface of the at least one substrate may be cleaned and / or etched with an acidic, alkaline, or pH-neutral cleaning composition prior to contact in step 1). Prior to step 1) of the present invention, one or more of the following optional steps may be performed, preferably in this order:

[0063] Step A): cleaning the surface of the substrate, preferably using an alkaline or neutral, preferably alkaline, aqueous cleaning composition, and optionally subsequently rinsing the surface of the substrate; and / or Step B): subjecting the surface of the substrate to acid pickling, i.e. etching, and optionally subsequently rinsing the surface of the substrate; and / or Step C): Activating the surface of the substrate using an aqueous activating composition different from the aqueous acidic composition of the present invention used in step 1).

[0064] Alternatively, optional steps A) and B) may be carried out in one step. Preferably, both steps A) and B) are carried out. The rinsing included in step A) is preferably carried out using deionized water or tap water. Preferably, the acid pickling in step B) is carried out using hydrochloric acid, hydrofluoric acid, sulfuric acid, nitric acid, oxalic acid, and / or phosphoric acid, more preferably hydrochloric acid. The activation composition used in optional step C) is used to deposit a plurality of ultrafine phosphate particles as seed crystals on the surface of the substrate used. These crystals serve to form a specific crystalline phosphate layer or a substantially closed phosphate layer on the surface in the subsequent contact step 1) with as many densely arranged fine phosphate crystals as possible. Therefore, the activation composition used in optional step C) preferably contains a phosphate, such as titanium phosphate and / or zinc phosphate, preferably zinc phosphate. Preferably, step C) is carried out. An example of a commercially available aqueous activation composition that can be used in step C) is the product Gardolene® V6526 from Chemetall GmbH.

[0065] Process 1) In step 1), at least one iron surface of at least one substrate is at least partially contacted with the aqueous acidic composition of the present invention, and a phosphate layer, i.e., a zinc phosphate layer, is formed on the portion of the surface that has been contacted with the composition in step 1).

[0066] The treatment procedure according to step 1), i.e. "contacting", includes, for example, spraying and immersion coating procedures. The composition can be applied by pouring onto the surface, by roll coating, or even by manual application by wiping or brushing. However, immersion is preferred. In this case, the substrate used is preferably immersed in a bath containing / obtained from the aqueous acidic composition of the present invention.

[0067] Preferably, contacting step 1) is carried out by at least partially immersing at least one iron surface of at least one substrate in a bath containing / obtained from the aqueous acidic composition of the present invention. The bath preferably has a temperature of 45-80°C, more preferably 45-75°C, even more preferably 50-70°C, and most preferably 50-65°C or 60°C or 55°C. The treatment time, i.e., the period of time during which the surface is in contact with the aqueous acidic composition, preferably does not exceed 10 minutes, more preferably <8 minutes, even more preferably <6 minutes, also more preferably does not exceed 5 minutes, even more preferably <4 minutes, and most preferably does not exceed 3 minutes.

[0068] Optional step 2) Optionally, the phosphate-treated surface obtained after step 1) can be rinsed with water. Preferably, such rinsing is carried out.

[0069] Optional step 3) Optionally, the phosphate-treated surface obtained after step 1) or optional step 2) can be dried. Preferably, such drying is carried out.

[0070] Drying step 3) may be carried out preferably at a temperature in the range of, for example, 15° C. to 80° C., more preferably at a temperature in the range of 18° C. to 60° C., and especially at 20° C. or at a temperature in the range of 23° C. to 50° C. Preferably, however, drying is carried out simply by blowing air at room temperature (15 to 23° C.).

[0071] Base material A further subject of the present invention is a substrate having at least one phosphate-treated surface, which substrate can be obtained by the phosphate treatment method described above, the phosphate-treated surface preferably having a phosphate content of 3 to 15 g / m 3 , more preferably 4 to 12 g / m 2 , and even more preferably 5 to 10 g / m 3 The coating weight is measured by the method disclosed in the "Methods" section.

[0072] All preferred embodiments described above for the inventive aqueous acidic composition, the inventive concentrate, the inventive method of use and the inventive phosphating method are also preferred embodiments of the inventive substrate, as well as the embodiments of the substrate itself outlined above for the inventive method of use.

[0073] Cold forming method A further subject of the present invention is a method for cold-forming a substrate having at least one iron surface, which method comprises a step of subjecting the substrate of the present invention having at least one phosphate-treated surface as defined above, or a substrate having at least one phosphate-treated surface obtainable from the method of the present invention described above, to a cold-forming process, preferably by drawing, before which the substrate is optionally subjected to a further step in which at least one lubricant is at least partially applied to the phosphate-treated surface. For this purpose, any type of lubricant can be used, such as soap, oil and / or polymer composition.

[0074] All preferred embodiments described above for the aqueous acidic composition of the invention, the concentrate of the invention, the method of use of the invention, the phosphating method of the invention, and the substrate of the invention are also preferred embodiments of the cold forming method of the invention.

[0075] All possible cold forming processes known in the prior art can be carried out, in particular rolling, e.g. thread rolling or impact forming, e.g. for nut or bolt blanks, drawing, in particular sliding drawing (tension-compression forming), e.g. for welded or plain pipes, hollow sections, solid sections, wire or rod, e.g. during wire drawing or tube drawing, or deep drawing, e.g. for strip or sheet metal, pressing, e.g. cold extrusion (pressure forming), e.g. for forming hollow or solid bodies), stretch forming (forming to gauge blocks / final dimensions) and / or cold expansion forming, e.g. for forming wire sections into fasteners such as nuts, etc.

[0076] The most common shapes formed from the substrate of the present invention are strip, sheet, slug, wire, wire coil, parts of more complex shape, sleeve, profile, e.g. hollow or solid profile, tube, disc, rod, bar or cylinder.

[0077] Preferably, the cold-formed substrate obtained after the cold-forming process still has at least a part of the phosphate layer obtained after carrying out step 1) and optionally step 3) of the phosphating method of the present invention.

[0078] method 1. Acid (S), Free Acid (FA) and Total Fischer Acid (TAF) The acid number (S value) is the FA:TAF ratio and is the free acid (FA) value divided by the total acid (TAF) value determined by the Fisher method.

[0079] To measure the amount of free acid (FA), 10 ml of the phosphated composition is pipetted into a suitable container, such as a 300 ml Erlenmeyer flask. Then, using a pH meter and electrode, it is titrated with 0.1 M NaOH to a pH of 3.8-4.2, preferably 4.0. The amount of 0.1 M NaOH consumed per 10 ml of phosphated composition, expressed in ml, gives the value of free acid (FA), expressed in points. To measure the amount of total acid by the Fischer acid factor (TAF), a dilute phosphated composition (10 ml of the phosphated composition is pipetted into a suitable container, such as a 300 ml Erlenmeyer flask, followed by the addition of potassium oxalate solution, followed by 150 ml of deionized water, using a pH meter and 0.1 M NaOH electrode) is titrated to a pH of 8.7. The amount of 0.1 M NaOH consumed per 10 ml of diluted phosphated composition, expressed in ml, gives the value of total Fischer acid (TAF), expressed in points.

[0080] 2. Phosphate Points (PP) PP is the sum of FA and TAF. It is measured as follows: 5 ml of phosphate solution is pipetted into an Erlenmeyer flask and diluted with 50 ml of distilled water. 25 ml of 30% by weight potassium oxalate solution and 10-15 drops of phenolphthalein are then added. The resulting solution is then titrated with 0.1 M sodium hydroxide solution until the color changes from colorless to red (pH 8.7). The phosphate point is determined by multiplying the amount of sodium hydroxide solution consumed by 2.

[0081] 3. Coating mass of phosphate layer The coating mass is determined by gravimetric measurement. The phosphate-treated test panel is weighed before and after removal of the coating, and the mass loss is measured. The coating is removed by dissolving it in a sodium hydroxide solution that also contains complex ions. For this, the panel is immersed in said solution for 5 minutes at 70 ° C, then rinsed with water and dried by blowing air. The panel is then reweighed, and the mass loss is measured to determine the mass of the coating, taking into account the known surface of the panel.

[0082] 4. ICP-OES The amount of certain elements in the samples to be analyzed is determined using inductively coupled plasma atomic emission spectrometry (ICP-OES) according to DIN EN ISO 11885 (date: 01.09.2009). [Example]

[0083] The following examples further illustrate the present invention but should not be construed as limiting its scope.

[0084] 1. Phosphating Composition 1.1 A fluoride-free and nickel-free phosphating composition IPC1 (inventive example) was prepared from deionized water, phosphoric acid, nitric acid, and suitable sources of zinc, copper, and magnesium cations. The components of the starting composition are shown in Table 1. IPC1 had a pH value ranging from 1.8 to 2.6. The S value was measured to be 0.33. The phosphate points (PP) were measured to be 30.

[0085] [Table 1]

[0086] 1.2 Aqueous acidic phosphating composition CPC1 (comparative) was prepared similarly to IPC1, except that no magnesium cation source was used in its preparation, so no magnesium cations were present in the composition.

[0087] 2. Phosphate Treatment Method The following iron substrates were used as metal workpieces:

[0088] a) Cold-rolled steel (CRS), substrate S1 (panel) b) Hot-rolled steel (HRS), substrate S2 (panel), and c) Steel alloys with less than 5% by weight of alloying material components, substrate S3 (wires and tubes).

[0089] Each workpiece was immersed in a cleaning bath prepared from a 50 g / L aqueous cleaning solution of Gardoclean® S5165 (available from Chemetall GmbH) and 5 g / L of GBA H7375 (available from Chemetall GmbH) at 65°C for 10 minutes, followed by rinsing with cold tap water for 1 minute. The surface-cleaned workpieces were then pickled in a 15% by weight HCl solution at room temperature for 1-20 minutes, depending on the substrate used, followed by rinsing with cold tap water for 1 minute. The workpieces were then activated with Gardolene® V6526 (available from Chemetall GmbH) by immersing them in the corresponding bath at room temperature for 1 minute. The workpieces were then immersed in a bath containing either IPC1 or CPC1 at a temperature range of 50-60°C for 3-10 minutes, followed by rinsing with cold tap water (twice). Finally, the resulting workpieces were dried at room temperature using compressed air.

[0090] 3. Investigation of phosphate-treated substrates, work equipment, and sludge formed during the phosphating process

[0091] 3.1 The coating mass of the phosphate layer present on each surface of the phosphate-treated substrate was measured to be 6-8 g / m 3 It was found to be in the range of

[0092] 3.2 No or only small amounts of deposits were found on the surface of the heating pipes of each phosphating bath.

[0093] 3.3 In all cases, only small amounts of soft sludge (which is small in volume compared to harder sludge) were formed.

[0094] 3.4 It was found that when using composition IPC1 (containing Mg cations), a lower bath temperature of only 50-55°C (saving energy) and a shorter treatment time of only 3-5 minutes (saving energy) were possible compared to using CPC1 (not containing Mg cations). As outlined in 3.1 above, when using IPC1, a coating density of 6-8 g / m2 was achieved after 3-5 minutes at a bath temperature of 50-55°C. 3 Coating masses in the range of 0.01 to 0.25 were measured, whereas with CPC1, the coating mass was only achieved after a treatment time of 7 to 10 minutes at 57 to 60°C. Furthermore, it was found that the presence of Mg cations in IPC1 stabilized the S value, so that no additional components had to be added after bath preparation to reduce this value.

Claims

1. At least components a1) to a5), which are free or substantially free of both fluoride anions and nickel cations and are different from one another, i.e. phosphate anions as component a1), nitrate anions as component a2), As component a3), zinc cations in an amount ranging from 5 to 60 g / L, calculated as the metal, and copper cations as component a4), Including, An acidic aqueous composition further comprising magnesium cations as component a5).

2. 2. The composition according to claim 1, characterized in that it comprises magnesium cations as component a5) in an amount ranging from 0.1 to 6.0 g / L, preferably from 0.2 to 5.0 g / L, even more preferably from 0.3 to 4.5 g / L, also more preferably from 0.4 to 4.0 g / L, still more preferably from 0.5 to 3.5 g / L, even more preferably from 0.6 to 3.0 g / L, also more preferably from 0.7 to 2.5 g / L, even more preferably from 0.8 to 2.0 g / L and most preferably from 1.0 to 2.0 g / L, in each case calculated as metal.

3. 3. The composition according to claim 1 or 2, characterized in that it comprises copper cations as component a4) in an amount ranging from 0.5 to 100 ppm, preferably from 0.7 to 80 ppm, also more preferably from 0.8 to 60 ppm, even more preferably from 0.9 to 40 ppm, also more preferably from 1 to 30 ppm, even more preferably from 3 to 25 ppm, still more preferably from 5 to 20 ppm and most preferably from 7 to 18 ppm, in each case calculated as metal.

4. 3. The composition according to claim 1 or 2, characterized in that it contains zinc cations as component a3) in an amount ranging from 5 to 50 g / L, preferably from 7 to 40 g / L, also more preferably from 10 to 30 g / L, even more preferably from 12 to 25 g / L, in each case calculated as metal.

5. the amount of magnesium cations present in the composition as component a5) expressed in g / L, calculated as metal, is greater than the amount of copper cations present in the composition as component a4), expressed in g / L, calculated as metal, and / or the amount of zinc cations present in the composition as component a3), expressed in g / L and calculated as the metal, is greater than the amount of both magnesium cations present in the composition as component a5) and copper cations present in the composition as component a4), expressed in g / L and calculated as the metal; 3. The composition according to claim 1 or 2, characterized in that

6. 3. A composition according to claim 1 or 2, characterized in that the relative mass ratio of zinc cations and magnesium cations to each other, in each case calculated as the metal, is in the range from 80:1 to 1.1:1, preferably from 70:1 to 1.2:1, more preferably from 60:1 to 1.5:1, even more preferably from 50:1 to 2:1, still more preferably from 40:1 to 3:1, also more preferably from 35:1 to 4:1, still more preferably from 30:1 to 5:1, even more preferably from 25:1 to 6:1, and most preferably from 22:1 to 8:

1.

7. phosphate anions as component a1) in an amount ranging from 5 to 60 g / L, preferably from 6 to 50 g / L, more preferably from 7 to 48 g / L, also more preferably from 8 to 40 g / L, still more preferably from 9 to 35 g / L, even more preferably from 10 to 30 g / L, also more preferably from 12 to 25 g / L, still more preferably from 14 to 20 g / L, in each case P ２ O ５ and / or Nitrate anions are contained as component a2) in an amount ranging from 10 to 100 g / L, preferably from 15 to 90 g / L, more preferably from 20 to 80 g / L, even more preferably from 25 to 70 g / L, and more preferably from 30 to 60 g / L, and most preferably from 35 to 50 g / L, in each case in the range of NO ３ is calculated as, The composition according to claim 1 or 2.

8. of nitrate anions present in the composition as component a2), expressed in g / L, NO ３ is the amount, expressed in g / L, of phosphate anions present in the composition as component a1), calculated as P ２ O ５ and preferably NO ３ and a nitrate anion calculated as P ２ O ５ 3. Composition according to claim 1 or 2, characterized in that the relative mass ratio of the phosphate anions to one another, calculated as: is in the range of from 15:1 to 1.1:1, preferably from 10:1 to 1.2:1, more preferably from 7.5 to 1.3:1, also more preferably from 5.0 to 1.5:1, and even more preferably from 4:1 to 2:

1.

9. 3. The composition according to claim 1 or 2, characterized in that it has a pH value in the range of 0.5 to 6.5, preferably 0.8 to 6.0, more preferably 1.0 to 5.5 or 5.0, even more preferably 1.2 to 4.5 or 4.0, also more preferably 1.5 to 3.5 or 3.0, and most preferably 1.7 to 3.0 or 2.

8.

10. A concentrate for producing a composition according to claim 1 or 2 by dilution with water.

11. 3. Use of the composition according to claim 1 or 2 for at least partially phosphating the iron surface of a substrate.

12. 1. A method for phosphating at least one iron surface of at least one substrate, comprising at least step 1), and optionally at least one of steps 2) and 3), namely 1) at least partially contacting at least one iron surface of at least one substrate with the aqueous acidic composition of claim 1 for phosphating at least one surface; 2) optionally rinsing the phosphate-treated surface obtained after step 1) with water; and 3) Optionally, drying the phosphate-treated surface obtained after step 1) or optional step 2). A method comprising:

13. 13. The method according to claim 12, characterized in that the contacting step 1) is carried out by at least partially immersing at least one iron surface of at least one substrate in a bath obtained from an aqueous acidic composition as defined in claim 1 or 2, preferably for a period of not more than 10 minutes, more preferably < 8 minutes, even more preferably < 6 minutes, also more preferably not more than 5 minutes, even more preferably < 4 minutes, and most preferably not more than 3 minutes, said bath preferably having a temperature of 45-80°C, preferably 45-75°C, more preferably 50-70°C, most preferably 50-65°C or 60°C or 55°C.

14. A substrate having at least one phosphate-treated surface, obtainable by the method according to claim 12, said phosphate-treated surface preferably having a coating weight of 3 to 15 g / m ３ , more preferably 4 to 12 g / m ２ , and even more preferably 5 to 10 g / m ３ The substrate is a surface having a phosphate layer having a surface area in the range of

15. 15. A method for cold-forming a substrate having at least one iron surface, characterized in that it comprises a step of subjecting a substrate according to claim 14 having at least one phosphate-treated surface, or a substrate having at least one phosphate-treated surface obtained from the method according to claim 12, to a cold-forming process, preferably by drawing, wherein prior to said cold-forming process, the substrate is optionally subjected to further steps and at least one lubricant is at least partially applied onto the phosphate-treated surface of the substrate.

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