Patent Application
20240124982
The invention relates to a method for the anti-corrosion pre-treatment of a plurality of components in series, in which the components of the series are at least partially formed of iron and/or steel, and in which the components of the series each initially undergo a first conversion stage, followed by a rinsing stage and a subsequent second conversion stage, wherein, in the conversion stages, respective acidic aqueous conversion solutions based on compounds of the elements Zr and/or Ti dissolved in water are brought into contact with the components, and, additionally, copper ions are contained in the conversion solution for the second stage.
In the anti-corrosion pre-treatment of components having surfaces made of the materials iron, steel, galvanized steel and/or aluminum, thin-film passivation based on amorphous conversion layers based on oxides and hydroxides of the elements Zr and/or Ti has become widely established as an alternative to phosphating, in the course of which crystalline coatings are formed. Efforts to further develop this type of conversion coating are essentially aimed at establishing resource-saving and chromium-free passivations that provide an excellent adhesive base for paint systems applied subsequently, wherein the aim is to achieve corrosion protection comparable to trication zinc phosphating. Especially in the case of amorphous thin films resulting from the conversion treatment of acidic aqueous solutions containing water-soluble compounds of the elements Zr and/or Ti, controlled film formation and growth of coatings with as few defects as possible is of great importance. In particular, it is difficult in this case to influence the kinetics of film formation in the thin diffusion film on the metal surface, in which an alkaline pH results in the coating based on the hydroxides and oxides of the elements Zr and/or Ti, in such a way that the conversion of the conversion treatment based mostly on fluoro complexes of the elements Zr and/or Ti is as complete as possible. This is to prevent fluorides from remaining in the thin film, which can cause localized film defects in contact with corrosive media. EP 1 455 002 A1 therefore reports that reducing the proportion of fluorides in the conversion coating can result in an improved corrosion behavior and paint adhesion to a subsequent electrodeposition coating. To effectively reduce the fluoride content in the conversion coating, EP 1 455 002 A1 proposes to add magnesium, calcium, an Si-containing compound, zinc, or copper to the conversion solution and alternatively, or in combination, to dry the conversion coating or post-rinse it with an alkaline aqueous composition.
Furthermore, in the prior art there are efforts to improve the quality of the conversion coating via a sequential structure of the coating. EP 2 318 566 A1, for example, shows that cascading the rinsing water of the conversion treatment into a pre-rinse before the actual conversion treatment is advantageous for the formation of amorphous coatings based on the elements Zr and/or Ti, in particular on steel surfaces, which protect against corrosion. According to EP 2 318 566 A1, a first slight conversion of the surface takes place during the pre-rinse, which is advantageous for the subsequent construction of the actual conversion layer. According to the teaching of EP 2 971 234 A1, a sequential layer structure by means of conversion in successive wet-chemical individual steps carried out independently of one another is also used to improve paint adhesion to correspondingly pre-treated steel surfaces. It describes a two-step process for the build-up of a conversion coating based on elements of the secondary groups IIIb/IVb of the periodic table, in particular on the element Zr, consisting of acidic fluoride-containing solutions, which is particularly suitable for a subsequent electrodeposition coating and can be carried out on various metal substrates.
Proceeding from this prior art, it is the object of the present invention to provide alternative methods for providing conversion coatings with as few defects as possible for a wide variety of metals, which then have improved protection against corrosive delamination after paint layer build-up. The method should be able to be carried out with as few resources as possible and should be particularly suitable for the treatment of components in series. Compared to the prior art, a significant improvement in corrosion protection and paint adhesion, at least on the surfaces of steel and/or iron, should also be achieved in a stable manner during the pre-treatment of a series of components to improve process quality.
This object is achieved by a method for the sequential build-up of a conversion coating in two treatment steps that are interrupted by a rinsing stage, wherein the conversion solutions each contain water-soluble compounds of the elements Zr and/or Ti and copper ions are additionally contained in the second conversion stage.
Specifically, the present invention relates to a method for the anti-corrosion pre-treatment of a plurality of components in series, in which the components of the series are at least partially formed of iron and/or steel, and in which the components of the series each undergo the successive method steps i)-iii) and at least the surfaces of iron and/or steel of the components are successively brought into contact with the respectively provided aqueous solutions (I)-(III):
Anti-corrosion pre-treatment of the components in series is when a large number of components are brought into contact with treatment solution provided in the respective treatment stages of the method according to the invention and conventionally stored in system tanks, the individual components being brought into contact successively and thus at different times. In this case, the system tank is the container in which the treatment solution is located for the purpose of anti-corrosion pre-treatment in series.
When, in the context of the present invention, reference is made to the pre-treatment of a component composed of a metallic material, in particular on the surfaces of the materials iron and steel to be subjected to the pre-treatment according to the invention, all materials containing the respective element to an extent of more than 50 at. % are thus included. An anti-corrosion pre-treatment always affects the surfaces of the component and thus of the metallic materials. The material can be a uniform material or a coating. According to the invention, galvanized steel grades consist both of the material steel and of the material zinc, it being possible for surfaces of steel to be exposed at the cutting edges and cylindrical grinding points of, for example, an automobile body which is made of galvanized steel, in which case according to the invention there is pre-treatment of the material steel.
Insofar as the concentration of an active component or compound is referred to in the context of the present invention as the amount of substance per kilogram, this is the amount of substance based on the weight of the respective total composition.
The components pre-treated according to the present invention can be three-dimensional structures of any shape and design that originate from a manufacturing process, in particular also including semi-finished products, such as strips, sheets, rods, pipes, etc., and composite structures assembled from said semi-finished products, in particular automobile bodies, the semi-finished products preferably being interconnected by means of adhesion, welding and/or flanging to form a composite structure.
With regard to the method steps, a solution (I)-(III) is considered to be “provided” in the sense of the method according to the invention if it is either prepared or held ready for contacting as defined in the respective treatment stage (i)-(iii) or is implemented during contact as defined.
The multi-stage pre-treatment according to the present invention, in comparison with a conversion treatment by one-time contacting with an acidic aqueous solution containing compounds of Zr and/or Ti dissolved in water and free fluoride (“conventional single-stage conversion layer formation”), provides defect-free conversion layers with a low fluoride content and a significantly reduced tendency to corrosive delamination of a subsequently built up paint system. The combination of a first conversion stage and a second conversion stage, which takes place after the rinsing stage in a conversion solution containing copper ions dissolved in water, is indispensable for this, and the mere reduction of the fluoride content in the conversion coating after the first conversion stage by means of the rinsing stage, which takes place with a rinsing solution containing substantially no free fluoride ions (i.e., less than 0.25 mmol/kg, preferably less than 0.10 mmol/kg, very particularly preferably less than 0.05 mmol/kg of free fluoride), is not sufficient, in particular not for sufficient performance in terms of corrosion protection on the steel and/or iron surfaces of the components of the series.
The amount of free fluoride in the relevant stages of the pre-treatment according to the invention can be determined potentiometrically by means of a fluoride-sensitive measuring electrode at 20° C. in the relevant provided solution after calibration with fluoride-containing buffer solutions without pH buffering.
The conversion layer formation in method steps i) and iii) is carried out by means of conversion solutions that produce an amorphous oxide/hydroxide coating based on the elements Zr and/or Ti and accordingly contain compounds of the elements Zr and/or Ti dissolved in water. The term “dissolved in water” comprises molecularly dissolved species and compounds that dissociate in aqueous solution and form hydrated ions. Typical representatives of these compounds are titanyl sulfate (TiO(SO4)), titanyl nitrate (TiO(NO3)2) and/or hexafluorotitanic acid (H2TiF6) and salts thereof or ammonium zirconium carbonate ((NH4)2ZrO(CO3)2) and/or hexafluorozirconic acid (H2ZrF6) and salts thereof. The compounds dissolved in water are preferably selected from fluoro acids and/or fluoro complexes of the elements Zr and/or Ti in the conversion stages. The conversion layer formation based on the fluoro acids and/or fluoro complexes of the element Zr is particularly preferred, because conversion layers of this kind provide improved paint adhesion.
Furthermore, it is advantageous for the formation of an extremely homogeneous and compact amorphous conversion layer if the pH of the conversion solution is not set to be acidic in order to keep the pickling rate as low as possible during the growth of the conversion layer, in particular in the first conversion stage. Overall, it is therefore preferred for both conversion stages in method steps (i) and (iii) that the pH is in each case above 3.0, more preferably above 3.5, particularly preferably above 4.0, but preferably below 4.5, because otherwise the precipitation of sparingly soluble hydroxides of the elements Zr and/or Ti in the interior of the solution can only be kept under control in a narrow process window during the serial treatment of a plurality of components.
An embodiment of the method according to the invention is particularly preferred in which the predominant part of the layer formation is already carried out in the first conversion stage and the second conversion stage only serves to remedy defects in the conversion coating formed in the first stage by deposition of a relatively small additional coating on the elements Zr and/or Ti, which is supported by the local cementation of copper at point defects in the conversion layer. Surprisingly, it has been found in this context that deposition of Zr and/or Ti beyond the required degree in the second conversion stage in turn significantly worsens the corrosion protection properties. This applies in particular to the surfaces of iron and/or steel of the components pre-treated according to the invention.
Accordingly, a method according to the invention is preferred in which the contacting with the conversion solution (i) in the first conversion stage in method step (i) takes place at least for a period of time during which a coating of at least 20 mg/m2 is produced on the surfaces of steel and/or iron, but the contacting is preferably not for so long that a coating of more than 150 mg/m2, more preferably more than 100 mg/m2, very particularly preferably more than 80 mg/m2 in each case based on the elements Zr and/or Ti results on these surfaces.
Now, as already explained above, in connection with such a coating brought about in the first conversion stage, it is advantageous for corrosion protection and paint adhesion, in particular on the surfaces of steel and/or iron, and it is therefore also preferred if the contacting with the conversion solution (III) in the second conversion stage in method step (iii) does not continue until there is an increase in the coating of more than 15 mg/m2, particularly preferably more than 12 mg/m2, very particularly preferably more than 10 mg/m2, on the surfaces of steel and/or iron, but the contacting is preferably carried out at least for such a period of time that the coating on these surfaces is increased by at least 2 mg/m2 in each case based on the elements Zr and/or Ti.
In this way, the layer structure in the conversion stages of the method according to the invention for anti-corrosion pre-treatment is optimally coordinated.
Preferred embodiments of the method according to the invention are shown and explained below with respect to the individual treatment stages and the method execution, which are particularly advantageous with respect to the object on which the invention is based.
In the first conversion stage, it is necessary to produce a conversion coating based on oxidic/hydroxidic compounds of the elements Ti and/or Zr as homogeneously as possible, while at the same time satisfying the requirements for process economy. The treatment time required for this purpose, i.e., the duration of contacting with the conversion solution at a temperature in the range of 10-60° C., should be in the range of 10 seconds to 300 seconds. In order to ensure this, a method according to the invention is preferred in which, in the conversion solution (I) of the first conversion stage in method step i), the proportion of compounds of the elements Zr and/or Ti dissolved in water is preferably at least 0.15 mmol/kg, more preferably at least 0.25 mmol/kg, particularly preferably at least 0.30 mmol/kg. For reasons of process economy, the content of compounds of the elements Zr and/or Ti dissolved in water should be significantly below 10.0 mmol/kg, particularly preferably below 5.0 mmol/kg.
However, a proportion of free fluoride is necessary in any case, depending on the type and surface properties of the metallic substrates, in particular the steel substrates, and the required pickling rate. In principle, it is advantageous, and therefore preferred, if in the conversion solution (I) of the first conversion stage in method step i), the proportion of free fluoride is at least 0.5 mmol/kg, particularly preferably at least 1.0 mmol/kg, and very particularly preferably at least 1.5 mmol/kg. However, for reasons of process economy and to prevent rust formation on the surfaces of steel and/or iron, especially after the rinsing stage, the proportion of free fluoride should preferably be less than 8.0 mmol/kg, particularly preferably less than 6.0 mmol/kg, very particularly preferably less than 5.0 mmol/kg.
A good balance of pickling rate and layer formation can be achieved if the quotient A in the conversion solution (I) of the first conversion stage in method step i) is according to Formula (1):
where F/mM and Me/mM are free fluoride (F) or reduced zirconium and/or titanium concentration (Me) reduced by the unit of the concentration in mmol/kg, is greater than 0.80, preferably greater than 1.20, particularly preferably greater than 1.60, so that such conversion solutions are preferred according to the invention.
Suitable sources of free fluoride in the first conversion stage of method step i) of the method according to the invention are hydrofluoric acid and the water-soluble salts thereof, such as ammonium bifluoride and sodium fluoride, as well as complex fluorides of the elements Zr, Ti and/or Si, in particular complex fluorides of the element Si. In a phosphating process according to the second aspect of the present invention, the source of free fluoride is therefore preferably selected from hydrofluoric acid and its water-soluble salts and/or complex fluorides of the elements Zr, Ti and/or Si. Salts of hydrofluoric acid are water-soluble within the meaning of the present invention if their solubility in deionized water (κ<1 μScm−1) at 60° C. is at least 1 g/L, calculated as F.
The rinsing stage in method step ii) of the method for sequential conversion coating according to the invention serves on the one hand for the complete or partial removal or dilution of soluble residues, particles and active components that are carried on the component in an adhering manner from the preliminary wet-chemical method step i). On the other hand, the removal of soluble residues should also specifically bring about the soluble fluoride species contained in the conversion coating, thus conditioning the first conversion coating for a subsequent passivating deposition of oxidic/hydroxidic Zr and/or Ti compounds and the cementation of copper in the second conversion stage. It has been found that the rinsing solution does not have to contain substantially any active components based on metal or semi-metal elements, which are consumed merely by the metal surfaces of the component being brought into contact with the rinsing liquid by deposition. Thus, the rinsing liquid can simply be municipal water or deionized water, or, if necessary, a rinsing liquid that can additionally contain redox-active compounds (“depolarizers”) to optimize the conditioning of the metal surface accessible at point defects, or additionally surface-active compounds, such as non-ionic surfactants or anionic surfactants, to optimize wettability with the rinsing solution.
It is therefore essential for the fulfillment of the purpose of the rinsing stage that the aqueous rinsing solution (II) provided in the rinsing stage has a concentration of compounds of the elements Zr and/or Ti dissolved in water, which is reduced in comparison with the aqueous conversion solution (I) at least by a factor of 5, preferably at least by a factor of 10, particularly preferably at least by a factor of 20, very particularly preferably at least by a factor of 50, and in this case comprises less than 0.25 mmol/kg, preferably less than 0.10 mmol/kg, particularly preferably less than 0.05 mmol/kg of free fluoride and preferably less than 0.10 mmol/kg of compounds of the elements Zr and/or Ti dissolved in water. In this case, the continuous reduction of soluble fluoride species in the conversion coating can also be achieved by bringing it into contact with rinsing solutions that contain a reduced concentration diluted by a factor of 5, for example by more than a factor of 100, of compounds of the elements Zr and/or Ti dissolved in water, can also be achieved in that the rinsing stage comprises a plurality of immediately successive rinsing steps, but preferably, for reasons of process economy, not more than three rinsing steps, with rinsing solutions (II) that contain at least one concentration, reduced by a factor of 5, of compounds of the elements Zr and/or Ti dissolved in water.
In view of the goal pursued with the rinsing stage, which is to bring about conditioning for the subsequent passivating deposition of oxidic/hydroxidic Zr and/or Ti compounds and the cementation of copper, it is advantageous and therefore preferred according to the invention if the rinsing solution(s) (II) of the rinsing stage contain(s) a total of less than 50 μmol/kg, preferably a total of less than 15 μmol/kg, of metal ions of the elements copper, nickel and cobalt that are dissolved in water.
According to the invention, the pH of the rinsing solution is in the range of 5.0 to 10.0. However, it has been found that alkaline rinsing solutions can be disadvantageous in that alkalinity is introduced into the second conversion stage, which must be compensated for there by resharpening with acidic substances and additionally promotes the precipitation of active components and thus sludge formation. Accordingly, it is preferred according to the invention if the aqueous rinsing solution (II), preferably at least the rinsing solution of the final rinsing step of the rinsing stage, has a pH above 6.0, but below 9.5, particularly preferably below 8.5 in method step (ii).
In a further aspect, it was possible to show that the conditioning of the surfaces of steel and/or iron provided with a first conversion layer for the subsequent passivating deposition of oxidic/hydroxidic Zr and/or Ti compounds and the cementation of copper in the second conversion stage is promoted by the fact that redox-active compounds that inhibit the formation of hydrogen on metal surfaces (referred to as “depolarizers”) are added to the rinsing solution. In a preferred embodiment of the method according to the invention, the aqueous rinsing solution (II) of the rinsing stage in method step (ii) therefore additionally contains at least 0.1 mmol/kg, more preferably at least 0.5 mmol/kg, particularly preferably at least 1 mmol/kg, but preferably no more than 10 mmol/kg, particularly preferably no more than 6 mmol/kg of a depolarizer selected from nitrate ions, nitrite ions, nitroguanidine, N-methylmorpholine N-oxide, hydrogen peroxide in free or bound form, hydroxylamine in free or bound form, reducing sugars, preferably selected from nitrite ions, nitroguanidine, hydroxylamine in free or bound form, hydrogen peroxide in free or bound form, particularly preferably selected from nitrite ions.
As already explained, the rinsing stage can take place in a plurality of successive rinsing steps if it is ensured that the respective rinsing solutions (II) each have a pH in the range of 5.0 to 10.0 and a concentration of compounds of the elements Zr and/or Ti dissolved in water that is reduced at least by a factor of 5 in comparison with the aqueous conversion solution (I) and contain less than 0.25 mmol/kg, preferably less than 0.10 mmol/kg, particularly preferably less than 0.05 mmol/kg of free fluoride. In a preferred embodiment, the contacting with the respectively provided rinsing solution in the rinsing stage of method step (ii) is carried out by dipping and/or spraying, preferably dipping and spraying, wherein dipping is preferably carried out first and then spraying.
The conversion of the metal surfaces of the component brought about in the second conversion stage serves, as has already been explained, primarily for the post-passivating deposition of oxidic/hydroxidic Zr and/or Ti compounds, so that, for reasons of process economy, but also for reliable compliance with the process window, relatively few active components of Zr and/or Ti in the conversion solution of the second conversion stage can be advantageous for optimum corrosion protection properties of the conversion layer constructed sequentially in the method according to the invention. Accordingly, a method according to the invention is preferred in which the conversion solution (III) of the second conversion stage in method step iii), the proportion of compounds of the elements Zr and/or Ti dissolved in water is less than 1.00 mmol/kg, preferably less than 0.80 mmol/kg, more preferably less than 0.70 mmol/kg, particularly preferably less than 0.60 mmol/kg.
In the second conversion stage, an amount of free fluoride is optional and it should be noted that the downstream conversion stage should not be set to be too mordanting at the same time in order to prevent the formation of local defects in the conversion coating. Nevertheless, a small amount of free fluoride may be useful for the cementation of the copper ions and the accelerated post-passivating deposition of oxidic/hydroxidic Zr and/or Ti for a short process time window. It is therefore preferred if, in the conversion solution (III) of the second conversion stage in method step iii), the proportion of free fluoride is less than 3.00 mmol/kg, preferably less than 2.50 mmol/kg, particularly preferably less than 2.00 mmol/kg, but preferably at least 0.1 mmol/kg, more preferably at least 0.2 mmol/kg, to support the increase in the coating on Zr and/or Ti. Suitable sources of free fluoride in the second conversion stage in method step i) of the method according to the invention are identical to those which are mentioned in connection with the first conversion stage.
Corrosion protection and paint adhesion, which are not sufficiently achieved until the second conversion stage, can be optimized by the amount of copper ions contained in the conversion solution (III). It is found that in the conversion solution (III) of the second conversion stage in method step iii), preferably more than 40 μmol/kg, particularly preferably more than 50 μmol/kg, should be contained. However, for reasons of process economy and for avoiding massive cementation of metallic copper, in particular when components are additionally pretreated with surfaces of zinc, it is preferred if no more than 500 μmol/kg, particularly preferably no more than 300 μmol/kg, and very particularly preferably no more than 200 μmol/kg of copper ions dissolved in water are contained in the conversion solution (II). Suitable sources of copper ions dissolved in water are water-soluble salts, such as copper nitrate (Cu(NO3)2), copper sulfate (CuSO4) and copper acetate (Cu(CH3COO)2).
With regard to the execution of the method according to the invention, it has been found that a transfer of the components from a “wet-in-wet” stage both into the rinsing stage and into the second conversion stage is advantageous, firstly for the removal of soluble residues from the first conversion layer and, finally, for the passivating deposition of the oxidic/hydroxidic compounds of the elements Zr and/or Ti and the cementation of copper. According to the invention, for reasons of process economy, a method is also preferred in which no drying step takes place between method steps (i) and (iii).
The anti-corrosion pre-treatment of the method according to the invention relates to a method execution for providing an amorphous conversion coating based on oxidic/hydroxidic compounds of the elements Zr and/or Ti, which provides an excellent paint adhesion primer for subsequently applied paint systems. Accordingly, it is preferred according to the invention if, after the method step (iii) with an intermediate rinsing step, but preferably without an intermediate drying step, a coating of the components is carried out using a paint system, preferably an electrodeposition coating, particularly preferably a cathodic electrodeposition coating.
In this context, a rinsing step is used exclusively for the complete or partial removal of soluble residues, particles and active components that are carried over by adhering to the component from the previous wet-chemical method step (iii), from the component to be painted, without metal-element-based or semi-metal-element-based active components, which are already consumed merely by bringing the metal surfaces of the component into contact with the rinsing liquid, being contained in the rinsing liquid itself. Thus, the rinsing liquid can simply be municipal water or deionized water, or, if necessary, a rinsing liquid that contains surface-active compounds to improve the wettability with the rinsing liquid, which are preferably nonionic surfactants that, in the case of a subsequent electrodeposition coating to improve coverage, are in turn selected in particular from alkoxylated alkyl alcohols and/or alkoxylated fatty amines, which are ethoxylated and/or propoxylated, wherein the number of alkylene oxide units is preferably in total no more than 20, more preferably no more than 16, but more preferably at least 4, particularly preferably at least 8, wherein the alkyl group preferably comprises at least 10 carbon atoms, more preferably at least 12 carbon atoms, wherein an HLB value is realized in the range of 12 to 16, which is calculated as follows:
HLB=20(1−Ml/M)
where Ml: molar mass of the lipophilic group of the non-ionic surfactant
A drying step in this context is a drying of the components caused by controllable technical precautions, for example by supplying heat or by means of directed air supply.
The contacting of the aqueous solutions (I)-(III) in method steps (i)-(iii) with the components or surfaces of steel and/or iron is not selective for the success of the method according to the invention, so that conventional methods, such as dipping, spraying and splashing, are preferred. The same applies with respect to the duration of the contacting in the respective treatment stages, which in each case is preferably in the range of 10-300 seconds, the temperature of the conversion solutions (I)-(II) during the contacting preferably being in the range of 10-60° C., particularly preferably in the range of 25-55° C., very particularly preferably in the range of 30-50° C.
With respect to the components, it is found that the method according to the invention is well suited for the anti-corrosion pre-treatment in series of materials composed of different metallic materials, the components of the series preferably also having surfaces of zinc and/or aluminum in addition to the surfaces of steel and/or iron. In addition to steel and iron, suitable metallic materials whose surfaces can be subjected to corrosion protection in the method according to the invention are zinc, electrolytic (ZE), hot-dip galvanized (Z) and alloy-galvanized (ZA), (ZF) and (ZM), and aluminum-coated (AZ), (AS) strip steel, as well as the light metals aluminum and magnesium and their alloys.
The advantages of a method sequence according to the invention are illustrated below on the basis of the anti-corrosion pre-treatment and cathodic electrodeposition coating of individual sheets of steel (CRS).
The proportion of free fluoride was adjusted by means of an aqueous solution of ammonium bifluoride and the adjustment of the pH with ammonium bicarbonate.
The pre-treated and electro-dip coated sheets were then aged for 6 weeks over 30 cycles according to the VW PV 1210 alternating climate test and the scribe delamination after aging was determined.
As a result, it is evident that the method according to the invention leads to a significant improvement in corrosion protection compared to a two-stage conversion treatment in which no intermediate rinsing step is carried out (Table 1: V3 vs. E1). The presence of copper ions in the second conversion stage is also crucial for sufficient corrosion protection (Table 1: V4 vs. E2). In addition, an increase in layer weight of less than 10 mg/m2 of Zr in the second conversion stage or a content of compounds of the elements Zr in the second conversion stage dissolved in water proves advantageous in preventing corrosive delamination after electrodeposition (Table 1: E3 vs. E4 and E1 vs. E2).
1 Corrosion and delamination according to DIN EN ISO 4628-8
2 Stone impact test according to DIN EN ISO 20567-1
| Number | Date | Country | Kind |
|---|---|---|---|
| 21183374.4 | Jul 2021 | EP | regional |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP2022/068099 | Jun 2022 | US |
| Child | 18543174 | US |
