JP2018517062A - Pre-cleaning liquid containing quaternary amine for conditioning prior to chemical conversion - Google Patents

Abstract

  The present invention relates to a multi-step method for pre-corrosion treatment of members made of metallic materials. The component is first subjected to a wet chemical treatment with an aqueous composition (A) comprising a salt of a quaternary amine and then to a further wet chemical treatment based on a water-soluble compound of the elements Zr, Ti and / or Si. In the course of the treatment, a corresponding modification of the surface of the metal material takes place, said treatment providing a corrosion-resistant primer for further applied organic coatings.

Description

  The present invention is a multi-step method for anti-corrosion pretreatment of a member composed of a metallic material, wherein after the conditioning wet chemical treatment with an aqueous composition (A) containing a salt of a quaternary amine, the element Further wet chemical treatments based on water-soluble compounds of Zr, Ti and / or Si are carried out, in this process the corresponding formation of the surface of the metal material is carried out, whereby corrosion resistance for further applied organic coatings It relates to the method in which the primer is applied.

  Chemical conversion of metal surfaces to provide coatings that provide protection against corrosion based on aqueous compositions containing water-soluble compounds of the elements Zr, Ti and / or Si is a technical field that has been extensively reported in the patent literature. . Since such metal pretreatment methods relate to corrosion protection and sufficient coating adhesion, various variations of such metal pretreatment methods are known to improve the property profile of such chemical conversion treatments. These are either related to the composition of the agent that results in chemical conversion, or utilize additional wet chemical processing steps in the direct context of chemical conversion processing.

  In European Patent Application No. 1455002, for example, in the chemical conversion treatment with the above composition further containing fluoride ions as a complexing agent for etching a metal surface, the fluoride fraction in the chemical conversion layer is reduced. Describes that it is advantageous to carry out an aqueous wash containing an alkaline reactive compound immediately after the actual wet chemical treatment or to continue the downstream drying step. Alternatively, the addition of specific cations selected from calcium, magnesium, zinc, copper or silicon-containing compounds to the composition resulting in surface conversion is used to reduce the fluoride content in the conversion layer. .

  With regard to the further adaptation of the procedure when using chemical water-soluble compounds containing fluoride ions and the elements Zr and / or Ti for the chemical conversion treatment, WO 2011/012443 describes fragrances containing at least one nitrogen heteroatom. A downstream aqueous washout is taught that includes an organic compound containing a group heterocyclic compound.

European Patent Application No. 1455002 International Publication No. 2011-012443

  Compared to this prior art, the object is to make the corrosion resistance properties of the conversion layer obtainable by pretreatment with a composition of water-soluble compounds of the elements Zr, Ti and / or Si more consistent in various metal substrates. In particular, to improve this on the steel surface. In particular, the average creep value of corrosive delamination after producing the coating-coated structure is improved. In an example of a further sub-embodiment, the pretreatment is performed in the substantial absence of fluoride for environmental health reasons. Therefore, in order for this sub-mode to be implemented, the pretreatment method according to the invention only comprises a so-called “metal-free surface”, ie a natural oxide layer even in the presence of fluoride. It must provide uniform and complete formation of the degreased washed metal surface. Furthermore, under the same conditions, the difference in the formation layer should be reduced, i.e. a specific formation should be reliably achieved from a process engineering point of view. For use on various metal substrates, in particular composites comprising surfaces made of at least one of zinc, galvanized steel and / or aluminum materials in addition to surfaces made of iron and / or steel materials It is desirable for the structure to have an optimum corrosion resistance with a suitable wet chemical pretreatment.

The object of the present invention is a multi-stage method for anti-corrosion pre-treatment of a component composed at least partly of a metallic material,
i) contacting at least a portion of the surface of the member formed of a metallic material with an aqueous composition (A) comprising a dissolved and / or dispersed salt of a quaternary organic amine (“conditioning”);
ii) one or more water-soluble elements Zr, Ti and / or Si with or without at least the same portion of the surface of the member formed of the metal material, with or without a flushing step and / or drying step in between Contact with aqueous composition (B) containing compound ("formation of chemical conversion layer")
Achieved by the method.

  The component to be processed according to the present invention may be a three-dimensional structure having any arbitrary shape and configuration, which is made in the composition process, and in particular semi-finished products such as ribbons, sheets, etc. , A rod, a tube, and the like, and a composite structure in which the aforementioned semi-finished products are assembled.

  According to the invention, in the first step i) of the process according to the invention, the conditioning treatment is carried out using an aqueous composition (A) comprising a dissolved and / or dispersed salt of a quaternary organic amine (“ conditioning"). As a result of this conditioning, a sufficient and uniform layer coating with respect to the elements Zr, Ti and / or Si is obtained in the course of the wet chemical treatment with the aqueous composition (B), so that the formation of the metal surface of the member is effective. To provide a potentially good coating primer. In particular, on steel surfaces, in the course of the process according to the invention, a reproducible layer coating with respect to the elements Zr, Ti and / or Si is obtained, which layer coating is further corrosive in the defects of the applied coating coating. A base for effectively suppressing creep.

  A salt of a quaternary organic amine dissolved or dispersed in water within the meaning of the present invention is one having an average particle diameter of less than 1 μm in the aqueous phase. The average particle diameter can be determined directly in the aqueous composition (A) at 20 ° C. in a form known as the D50 value from the cumulative particle size distribution according to ISO 13320: 2009 by laser diffraction.

  The presence of the quaternary organic amine in the aqueous composition (A) in step i) increases the suitability of the conversion coating applied in step ii) and serves as a good coating primer. In the context of the present invention, quaternary organic amines are those which have only a covalent bond with a carbon atom and thus contain at least one nitrogen atom which has a permanent positive charge.

In the context of the compounds of the present invention, the quaternary organic amine is preferably one having a weight average molecular weight _Mw of less than 5,000 g / mol.

  Furthermore, in particular, heterocyclic compounds containing at least one nitrogen heteroatom having only a covalent bond with a carbon atom have been shown to be suitable quaternary organic amines, so that they are in the process according to the invention It is a preferred component of the aqueous composition (A).

の、少なくとも１つの窒素ヘテロ原子を含む複素環式化合物である。 In a preferred embodiment, the quaternary organic amine present in the aqueous composition (A) comprises functional groups R ¹ , R ² and R ³ each having hydrogen or 6 or fewer carbon atoms. aliphatic compounds or functional groups branched or unbranched _{^{- (CR 4 R 4) x}} - [Z (R 4) (p-1) - (CR 4 R 4) y] n -Z (R 4) p Where Z is selected from oxygen or nitrogen, p has a value of 2 if Z is nitrogen, 1 otherwise, and x and y are each a natural number of 1 -4, n is likewise a natural number 0-4, R ⁴ is selected from hydrogen or branched or unbranched aliphatic compounds having up to 6 carbon atoms, provided that the functional group R ^At least one of ² or R ³ is not selected from hydrogen;
1 or less bridging heteroatoms that are not carbon atoms and include Y as a divalent ring-constituent functional group having 5 or less bridging atoms and selected from oxygen, nitrogen or sulfur may be bridging atoms; In this case, the carbon atoms are present independently from each other by the substitution of the functional group R ¹ or a functional group capable of achieving cyclization of an aromatic homocyclic compound having 6 or less carbon atoms, I):

A heterocyclic compound containing at least one nitrogen heteroatom.

In general, it has been found convenient that the quaternary organic amine is one represented by a heterocyclic compound containing a skeleton of imidazole, imidazoline, pyrimidine, purine and / or quinazoline. Therefore, in the context of the present invention, the heterocyclic compound according to the chemical formula (I) has, as the divalent functional group Y constituting the ring, ethylene, ethenediyl, 1,3-propanediyl, 1,3-propenediyl, , 4-butanediyl, 1,4-butenediyl, 1,4-butadienediyl, —CH═N—, —CH ₂ —NH—, (N, N-dimethylene) amine, (N-methylene-N-methylidene) )) Amines, particularly preferably selected from ethenediyl, 1,4-butadienediyl, -C = N- or (N-methylene-N-methylidene) amine, particularly preferably selected from ethenediyl or -C = N-. , Very preferably containing substituents selected from ethenediyl, where in each case Hydrogen that is covalently bonded to the atom may be substituted by a portion representing the remainder of the functional group R ¹ by the general formula (I).

  Quaternary organic amines that have proven particularly advantageous are 1,2,3-trimethylimidazolium, 1-methyl-3-methylimidazolium, 1-ethyl-3-methylimidazolium, 1-isopropyl-3. -Methylimidazolium, 1-propyl-3-methylimidazolium, 1- (n-butyl) -3-methylimidazolium, 1- (isobutyl) -3-methylimidazolium, 1-methoxy-3-methylimidazolium 1-ethoxy-3-methylimidazolium, 1-propoxy-3-methylimidazolium, preferably 1,2,3-trimethylimidazolium.

  According to the invention, the proportion of quaternary organic amine in the aqueous composition (A) is at least 0.05 g / kg, preferably at least 0.2 g / kg, particularly preferably at least 0.4 g / kg. It is generally advantageous if it is preferably 5 g / kg or less, particularly preferably 10 g / kg or less.

  If it exceeds 10 g / kg, no further suppression of corrosive delamination after forming the coating film structure is observed even when the washing step is performed after the conditioning of step i). The use of any amount of quaternary organic amine in excess of can be uneconomical in the process according to the invention.

  In general, any anion, especially sulfates, nitrates, chlorides, carbonates and organic anions such as alkyl sulfates, alkyl sulfonates, alkyl phosphates and / or alkyl phosphonates can be used as counterions for quaternary organic amines.

  Surprisingly, preferably from monoalkyl sulfates, monoalkyl sulfonates, dialkyl phosphates and / or dialkyl phosphonates having 5 or less carbon atoms, preferably monoalkyl sulfates having preferably 5 or less carbon atoms And / or the presence of an anion (K) selected from monoalkyl sulfonates, particularly preferably from methyl sulfate, is found to be advantageous for the formation of a uniform conversion layer in step ii) of the process according to the invention, Therefore, the further presence of such anions is correspondingly preferred.

  Consequently, the anion (K) is also preferably an anion-forming component of the salt of the quaternary organic amine, so that the corresponding salt thus has both a quaternary amine source and an anion (K) source. Therefore, the amount of ions in the aqueous composition (A) can be minimized. Thus, in addition to the alkali metal and / or alkaline earth metal salts and the corresponding ammonium salts, suitable anion (K) sources are in particular the corresponding salts of the quaternary organic amines mentioned above.

According to the present invention, the proportion of anion (K) in the aqueous composition (A) is preferably calculated as SO ₄ equivalent to the aqueous composition (A), preferably at least 0.05 g / kg, in particular Preferably it is at least 0.2 g / kg, more particularly preferably at least 0.4 g / kg, but this proportion is preferably 5 g / kg or less, particularly preferably 3 g / kg or less. Above 5 g / kg, the formation of the conversion layer in step ii) does not increase further or becomes more consistent even if the washing step is performed after the conditioning in step i). Thus, the use of any amount of conditioning agent above this level can be uneconomical in the process according to the invention.

  The pH value of the aqueous composition (A) of step i) can be selected substantially freely and is usually in the range 2-14, preferably above 3.0, particularly preferably above 4.0, further Particularly preferably, it is above 5.0, preferably below 12.0, particularly preferably below 10.0, and even more preferably below 8.0.

  Furthermore, in the treatment of parts comprising a surface made of zinc and / or galvanized steel material, the aqueous composition (A) further results in a thin iron-coated structure on the surface when in contact with the zinc surface, thus corroding It may be advantageous to contain an amount of iron ions that further contributes to making the defense more consistent, which is utilized by the method according to the invention, especially on surfaces made of iron material. It becomes possible. This type of ironing is preferably a complexing agent according to the teachings of WO 2008/135478 in an acidic environment, preferably in the presence of a reducing agent, or according to the teachings of WO 2011/098322 in an alkaline environment. And in the presence of phosphate ions.

  According to the invention, further components may be included in the aqueous composition (A). In addition to the pH adjusting substance, it may also contain a surface active substance, and its use is preferred in the aqueous composition (A) having a cleaning action.

  However, in a preferred embodiment, the aqueous composition (A) contains less than 0.05 g / kg, preferably less than 0.01 g / kg, particularly preferably less than 0.001 g / kg of surface active compound (this is the fourth So that the interaction between the surface active compound and the surface of the metal material of the component does not compete with the interaction with the quaternary organic amine, thereby ensuring that each desired technique Does not counteract the effects.

Surface-active compounds in the sense of the present invention are those having an HLB (Hydrophilic Lipophilic Balance) value of less than 5 or greater than 10. The HLB value is calculated according to the following formula and can take values from zero to 20 on any scale:
HLB = 20 · (1−M ₁ / M)
(Wherein, M ₁ : molecular weight of lipophilic group of nonionic surfactant; M: molecular weight of nonionic surfactant)

Furthermore, the dissolved and / or dispersed organic polymer which is not a quaternary organic amine contained in the aqueous composition (A) of step i) of the process according to the invention is less than 0.5 g / kg in total, particularly preferably 0. Preferred is a case of less than 1 g / kg, particularly preferably less than 0.05 g / kg. Thus, as described above with respect to the presence of the surface active compound, the interaction of such a polymer with the surface of the metallic material of the member is a conditioning agent or a quaternary organic amine interaction further present in a preferred embodiment of the present invention. It is ensured that there is no competition, thereby not counteracting each desired technical effect. The dissolved or dispersed organic polymer in the context of the present invention has a weight average molecular weight _Mw of at least 5,000 g / mol and an average particle diameter in the aqueous phase of less than 1 μm. The average particle diameter can be determined directly in the aqueous composition (A) at 20 ° C. in a form known as the D50 value from the cumulative particle size distribution according to ISO 13320: 2009 by laser diffraction.

In one example of a preferred method according to the present invention, no conversion layer is formed on the surface of the metal member in step i). Thus, the aqueous composition (A) has any component in an amount that can allow the conversion layer to form on the surface of the metallic material of the member during the time provided for conditioning in step i). Not included. The conversion layer in the conditioning process of step i) of the method according to the invention is present when a cover layer is produced on each surface of the metal material by a wet chemical process, which comprises a titanium group, a vanadium group. And / or phosphates, oxides and / or hydroxides of the elements of the chromium group or phosphates of the elements calcium, iron and / or zinc in the coated structure, at least 5 mg in terms of the respective transition metal / M ² or at least 50 mg / m ² in terms of phosphorus element. Corresponding transition metals can be quantitatively measured by X-ray fluorescence (XRF) analysis, while the covering structure is about 5 wt. Acid wash in% aqueous CrO ₃ followed by quantitative measurement by atomic emission spectrometry (ICP-AES).

In order to suppress the formation of a conversion layer on the surface of the metal material of the component, the method according to the invention is preferably based on each element, the aqueous composition (A) of step i) is less than 0.005 g / kg, in particular Preferably less than 0.001 g / kg of elements Zr, Ti and / or Si water soluble compounds, preferably less than 1 g / kg of elements Zn, Mn and Ca based on each element, and / or preferably Is characterized in that it contains less than 0.05 g / kg, particularly preferably less than 0.01 g / kg of free fluoride (when measured at 20 ° C. with a fluoride sensitive electrode). In a further preferred embodiment, the total proportion of fluoride in the aqueous composition (A) is less than 0.05 g / kg, particularly preferably less than 0.02 g / kg, particularly preferably less than 0.01 g / kg. The total proportion of fluoride (total fluoride) is determined at 20 ° C. by a fluoride sensitive electrode in a TISAB buffer aliquot of the aqueous composition (A) (TISAB: total ionic strength adjusting buffer solution), where the aqueous composition The volume-based mixing ratio of the buffer to the aliquot of (A) is 1: 1. TISAB was prepared by dissolving 58 g NaCl, 1 g sodium citrate and 50 ml glacial acetic acid in 500 ml deionized water (κ < ¹ μScm ⁻¹ ), setting the pH to 5.3 with 5N NaOH, and again deionizing. Prepared by adding water (κ <1 μScm −1) until the total volume is 1000 ml.

In process step ii), an amount of active ingredient sufficient to form a conversion layer should be present in the acidic aqueous composition (B). In this regard, the aqueous composition (B) of step ii) is preferably at least 0.01 g / kg, particularly preferably at least 0.05 g / kg, more particularly preferably at least 0.1 g / kg of elemental Zr, Ti or It is advantageous to contain a water-soluble compound of Si (in terms of each element Zr, Ti or Si). In this connection it should be noted that such compounds according to the invention are considered water-soluble if their solubility in deionized water (κ < ¹ μScm ⁻¹ ) is at least 1 g / L at 20 ° C. .

  In view of economy, it is more convenient that the total proportion of these compounds is preferably 0.5 g / kg or less in terms of elements Zr, Ti and Si. This is because at higher contents, there is usually no further improvement in the corrosion resistance properties of the conversion layer and the deposition rate is increased, making it more difficult to control the coating structure with respect to these elements. .

Due to the conditioning of step i) of the process according to the invention, a water-soluble compound of the fluorine-free element Zr, Ti or Si is also used in the aqueous composition (B) to bring about sufficient conversion of the surface of the metallic material of the component. Preferred and therefore preferred. Silanes containing (NH ₄ ) ₂ Zr (OH) ₂ (CO ₃ ) ₂ , ZrO (NO ₃ ) ₂ or TiO (SO ₄ ) or at least one covalent Si—C bond are particularly preferred representatives.

  As described above, the use of the complex fluoride in step ii) to bring about the formation of the surface of the metallic material of the component, and also the use of free fluoride is the method of the invention according to the invention by conditioning in step i). Can be omitted. Therefore, the preferred method according to the present invention is that the proportion of free fluoride in the aqueous composition (B) is less than 0.05 g / kg, less than 0.01 g / kg, 0.001 g / kg in order of increasing preference. Less than 0.0001 g / kg, more particularly preferably free fluoride is not present. Furthermore, in a preferred embodiment of the method according to the invention, the total proportion of fluoride (total fluoride) in the aqueous composition (B) is less than 0.05 g / kg, 0.02 g in order of increasing preference. / Kg, less than 0.01 g / kg, less than 0.001 g / kg and less than 0.0001 g / kg, more particularly preferably no fluoride. The percentage of free fluoride and the total percentage of fluoride can be confirmed in the same manner as the procedure used to measure the same parameters of the aqueous composition (A).

The best results with respect to corrosion protection are obtained when copper ions are present in the aqueous composition (B) of step ii) in combination with the conditioning of step i). Thus, in a particularly preferred embodiment of the method according to the invention, the aqueous composition (B) further comprises a water-soluble compound that is a source of copper ions, preferably water-soluble salts such as copper sulfate, copper nitrate and acetic acid. It contains a water-soluble compound in the form of copper. In this connection it should be noted that such compounds according to the invention are considered water-soluble if their solubility in deionized water (κ < ¹ μScm ⁻¹ ) is at least 1 g / L at 20 ° C. .

  The content of copper derived from the water-soluble compound in the aqueous composition (B) is preferably at least 0.001 g / kg, particularly preferably at least 0.005 g / kg. However, the copper ion content preferably does not exceed 0.1 g / kg, particularly preferably does not exceed 0.05 g / kg. This is because otherwise the deposition of copper element begins to dominate the formation of the conversion layer.

  The pH value of the aqueous composition (B) is preferably in the acidic range, particularly preferably in the range of 2.0 to 5.0, and still more preferably in the range of 2.5 to 3.5.

  More preferably, the aqueous composition (B) contains nitrate ions as an accelerating factor for the formation of the chemical conversion layer. In this case, the proportion of nitrate ions is preferably at least 0.5 g / kg, but for economic reasons. From, preferably not exceeding 4 g / kg.

  Surprisingly, this success according to the present invention is brought about substantially independently of carrying out a washing and / or drying step immediately after the conditioning of step i). The difference in the performance of the process brought about by the wash-out process carried out in between is usually compensated by increasing the concentration of the quaternary organic amine and the anion (K) in the aqueous composition (A) appropriately. be able to. In any case, the general suitability of the method for achieving the object of the invention is not affected by carrying out a washing and / or drying step between method steps i) and ii). However, from a process engineering point of view, it is preferred to carry out a washing step immediately after step i) in the process according to the invention in order to separate the active ingredients in the individual processing steps, in this case preferably before step ii). The drying process is not performed.

  According to the present invention, the washing-out step is integrated with a water-soluble residue, a chemical compound that is not firmly adhered, and free solid particles derived from the member to be treated (these are integrated with the wet film adhered to the member, It is always used to remove the scooping from the previous wet chemical treatment step by the aqueous liquid medium. The aqueous liquid medium does not contain any chemical component that makes the member constituted by the surface of the metal material significantly covered with a transition metal, a semimetal or a polymer organic compound. However, such a significant surface coverage is at least 10 milligrams per square meter of washed liquid liquid medium, preferably at least 1 milligram per square meter of flushed surface (in terms of specific elements or specific macromolecular organic compounds). Present when the components (in terms of each element or each macromolecular organic compound) are in a depleted state (the increased amount resulting from the carry-over from the wet film in close contact with the member and the loss due to scooping are considered) do not do).

  According to the present invention, the drying step is an aqueous liquid that adheres to the surface of the member as a result of the provision and use of technical means, in particular by supplying thermal energy or applying an air stream. Any process step intended to dry the membrane.

  The member to be treated in the method according to the invention is at least partly made of a metal material. Preferred metallic materials that clearly show improved properties of the conversion layer as a coating primer are iron and iron alloys, especially steel. An iron alloy in this context is to be understood as meaning a material in which at least 50 at% of the respective material is formed of iron atoms. On surfaces made of iron and its alloys, there was a significant improvement in corrosion protection with respect to the corrosive creep of the defects, which had been washed and / or dried immediately after conditioning in step i) It comes with virtually no matter what.

  In the process according to the invention, after step ii), preferably an organic coating is applied, in particular powder coating or dip coating (which is more preferably electrodeposition dip coating). The electrodeposition dip coating is preferably carried out in the washing step, but is particularly preferably not carried out in the drying step.

  In a preferred embodiment of the method according to the invention, the member comprises a surface made at least partly of iron and / or steel material, wherein the member surface is preferably a surface made of metal material. Is formed of a surface made of iron and / or steel material, at least 50%, particularly preferably at least 80%.

  However, in principle, in addition to composite structures and in particular surfaces made of iron and / or steel materials, zinc and / or galvanized steel and aluminum materials (if necessary, of phosphate A member that also includes a surface made in) can be treated in the method according to the invention.

In addition, if the component includes surfaces made of zinc and / or galvanized steel material, a thin amorphous layer containing iron is applied over these surfaces to provide effective conditioning, for example, iron and It is generally preferred that what is normally found on surfaces made of steel materials is applied to the surfaces made of these materials as well in step i) of the process according to the invention. In this regard, particularly effective ironing of surfaces made of zinc and / or galvanized steel is described in the documents WO 2011/098322 and WO 2008/135478, in each case wet. In the form of chemical processes, these can be applied in an equivalent manner just before carrying out process step i) according to the invention. In this respect, in the process according to the invention in which the member is made at least partly of zinc and / or galvanized steel material, at least 20 mg / m ² of the surface of the member composed of these materials, but preferably 150 mg / M ² or less is preferably coated with iron.

  Exemplary embodiments:

  In the following, a sheet made of steel (CRS) is subjected to a multi-stage process for anti-corrosion pretreatment. The suitability of the metal sheet pretreated in this way and provided with a coating structure that functions as a good coating primer is examined in a test for corrosive delamination according to DIN EN ISO 4628-8.

A general method for pretreatment and coating involves a continuous essential and optional individual steps (A) to (E):
(A) Alkali cleaning and degreasing:
The sheet is stirred for 5 minutes at 56 ° C. in an alkaline detergent composed of 4% by weight Ridoline® 2011 (Henkel) and 0.4% by weight Ridosol® 1270 (Henkel). Soak;
(B) Rinse with process water followed by deionized water (κ < ¹ μScm ⁻¹ ), each at 20 ° C .;
(C) By immersing the sheet in a composition containing a predetermined amount of a “conditioning agent” in deionized water (κ < ¹ μScm ⁻¹ ) for 1 minute at 35 ° C. and not further added with a pH-changing substance. Conditioning;
(D) If necessary, rinse with deionized water (κ < ¹ μScm ⁻¹ ) at 20 ° C. (E) The sheet has a pH value of approximately 2.6 at 35 ° C. for 3 minutes, 1.6 g / A chemical conversion treatment is carried out by immersing in an aqueous composition containing kg of ZrO (NO ₃ ) ₂ .

Following the chemical conversion treatment in method step (E), each sheet was first rinsed with deionized water (κ < ¹ μScm ⁻¹ ) at 20 ° C., then coated with electrophoretic coating and dried at 180 ° C. (drying) Layer thickness: 18-20 μm; CathoGuard (registered trademark) 800, manufactured by BASF Coatings)

Table 1 below shows the various organic compounds used in the conditioning of step (C).

In an experiment in which chemical conversion treatment is performed only based on a composition not containing fluoride (No. 1), a zirconium covering structure in the range of 0 to ²⁰ mg / m ² is reproducibly applied on the steel sheet in the step (D). Obviously you can't. Similarly, preconditioning based conditioning using an aqueous solution containing polyvinylpyrrolidone (No. 2) is rejected because the formation of the conversion layer is not performed at a high level and is not reproducible as a whole. Significant conversion of the steel surface is obtained only with the addition of imidazolium salts, which is generally sufficient for good corrosion protection and in the range of 15-60 mg / m ² which serves as a good coating primer. Work capacity is obtained (No. 3 and No. 4). If more methyl sulfate anions are present, a greater acceleration of formation of the conversion layer is observed (# 5).

The results of corrosion and the order of each related process are shown in Table 2.

Claims (15)

A multi-stage method for anti-corrosion pretreatment of a component composed at least in part of a metallic material,
i) contacting at least a portion of the surface of the member formed from the metal material with an aqueous composition (A) comprising a dissolved and / or dispersed salt of a quaternary organic amine;
ii) A method in which at least the same portion of the surface of a member formed of a metal material is brought into contact with an aqueous composition (B) containing one or more water-soluble compounds of the elements Zr, Ti and / or Si.   The process according to claim 1, characterized in that the quaternary organic amine is selected from heterocyclic compounds containing at least one quaternary nitrogen heteroatom. Heterocyclic compounds containing at least one quaternary nitrogen heteroatom contain functional groups R ¹ , R ² and R ³ , which are hydrogen or branched or unbranched fatty acids having up to 6 carbon atoms family compounds or functional groups _{- (CR 4 R 4) x} - [Z (R 4) (p-1) - (CR 4 R 4) y] n -Z (R 4) is selected from _p, where where And Z is selected from oxygen or nitrogen, p has a value of 2 when Z is nitrogen, 1 otherwise, x and y are each a natural number of 1-4, n is likewise a natural number 0-4, and R ⁴ is selected from hydrogen or branched or unbranched aliphatic compounds having up to 6 carbon atoms, provided that the functional groups R ² and R ³ At least one is not selected from hydrogen;
1 or less bridging heteroatoms that are not carbon atoms and include Y as a divalent ring-constituent functional group having 5 or less bridging atoms and selected from oxygen, nitrogen or sulfur may be bridging atoms; The carbon atoms are present independently of one another, substituted with a functional group R ¹ or a functional group that achieves cyclization of an aromatic homocyclic compound having 6 or less carbon atoms, the following chemical formula (I):

The method according to claim 2, which corresponds to: The divalent functional group Y constituting the ring is ethylene, ethenediyl, 1,3-propanediyl, 1,3-propenediyl, 1,4-butanediyl, 1,4-butenediyl, 1,4-butadienediyl, —CH ═N—, —CH ₂ —NH—, (N, N-dimethylene) amine, (N-methylene-N-methylidene) amine, preferably ethenediyl, 1,4-butadienediyl, —C═N Or selected from (N-methylene-N-methylidene) amine, particularly preferably selected from ethenediyl or —C═N—, very preferably selected from ethenediyl, in each case shared by carbon atoms bonded to are hydrogen, characterized in that optionally substituted by the remainder of the functional groups R ^1, a method according to claim 3.   The quaternary organic amine is 1,2,3-trimethylimidazolium, 1-methyl-3-methylimidazolium, 1-ethyl-3-methylimidazolium, 1-isopropyl-3-methylimidazolium, 1-propyl. -3-methylimidazolium, 1- (n-butyl) -3-methylimidazolium, 1- (isobutyl) -3-methylimidazolium, 1-methoxy-3-methylimidazolium, 1-ethoxy-3-methyl 5. Process according to any of claims 1 to 4, characterized in that it is selected from imidazolium, 1-propoxy-3-methylimidazolium, preferably from 1,2,3-trimethylimidazolium.   The composition (A) of step (i) is selected from monoalkyl sulfates, monoalkyl sulfonates, dialkyl phosphates and / or dialkyl phosphonates, preferably having no more than 5 carbon atoms, preferably no more than 5 carbons 6. The process according to claim 1, further comprising an anion selected from monoalkyl sulfates and / or monoalkyl sulfonates having atoms, particularly preferably selected from methyl sulfates.   The proportion of quaternary organic amine in the composition (A) is at least 0.05 g / kg, preferably at least 0.2 g / kg, particularly preferably at least 0.4 g / kg, preferably 20 g / kg. The method according to claim 1, wherein the method is particularly preferably 10 g / kg or less.   The method according to claim 1, wherein no chemical layer is created on the surface of the metal member in step i).   Composition (A) is characterized in that it contains less than 0.05 g / kg, preferably less than 0.01 g / kg, particularly preferably less than 0.001 g / kg of a surface-active compound free from quaternary organic amines. The method according to any one of claims 1 to 8.   The composition (B) in step ii) is at least 0.01 g / kg, preferably at least 0.05 g / kg, particularly preferably at least 0.1 g / kg of the elements Zr, Ti or Si based on the respective elements. The method according to claim 1, comprising a water-soluble compound.   The composition (B) in step ii) comprises less than 0.05 g / kg, preferably less than 0.01 g / kg, particularly preferably less than 0.001 g / kg of free fluoride. The method in any one of 1-10.   The total proportion of fluoride in the composition (B) in step ii) is less than 0.05 g / kg, preferably less than 0.01 g / kg, particularly preferably less than 0.001 g / kg, even more preferably 0.0001 g. The method according to claim 1, wherein the method is less than 1 kg.   13. A method according to any one of the preceding claims, characterized in that the cleaning and degreasing step of the member is performed prior to step i), preferably by contacting with an aqueous composition comprising a surface active compound. .   14. A method according to any one of the preceding claims, characterized in that, between the process steps i) and ii), the washing off step is preferably not performed.   The member has at least partly a surface of iron and / or steel material, preferably at least 50%, particularly preferably at least 80% of the metal material surface of said member is formed of the surface of iron and / or steel material 15. A method according to any of claims 1 to 14, characterized in that