WO2022048963A1 - Procédé en une étape pour la phosphatation du zinc - Google Patents

Procédé en une étape pour la phosphatation du zinc Download PDF

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Publication number
WO2022048963A1
WO2022048963A1 PCT/EP2021/073476 EP2021073476W WO2022048963A1 WO 2022048963 A1 WO2022048963 A1 WO 2022048963A1 EP 2021073476 W EP2021073476 W EP 2021073476W WO 2022048963 A1 WO2022048963 A1 WO 2022048963A1
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WIPO (PCT)
Prior art keywords
zinc
weight
particularly preferably
aqueous composition
phosphating
Prior art date
Application number
PCT/EP2021/073476
Other languages
German (de)
English (en)
Inventor
Ralf POSNER
Marc Balzer
Matthias Hamacher
Jan-Willem Brouwer
Kristof WAPNER
Christina ANGENENDT
Original Assignee
Henkel Ag & Co. Kgaa
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Henkel Ag & Co. Kgaa filed Critical Henkel Ag & Co. Kgaa
Priority to EP21762057.4A priority Critical patent/EP4208585A1/fr
Priority to MX2023002586A priority patent/MX2023002586A/es
Priority to KR1020237007293A priority patent/KR20230061381A/ko
Priority to JP2023514888A priority patent/JP2023540976A/ja
Priority to CN202180054117.6A priority patent/CN116096945A/zh
Publication of WO2022048963A1 publication Critical patent/WO2022048963A1/fr
Priority to US18/174,102 priority patent/US20230220559A1/en

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
    • C23F11/18—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using inorganic inhibitors
    • C23F11/187—Mixtures of inorganic inhibitors
    • C23F11/188—Mixtures of inorganic inhibitors containing phosphates
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
    • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
    • C23C22/34—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing fluorides or complex fluorides
    • C23C22/36—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing fluorides or complex fluorides containing also phosphates
    • C23C22/362—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing fluorides or complex fluorides containing also phosphates containing also zinc cations
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • C23F11/04—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in markedly acid liquids
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
    • C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
    • C23F11/173—Macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D13/00—Electrophoretic coating characterised by the process
    • C25D13/20—Pretreatment
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D13/00—Electrophoretic coating characterised by the process
    • C25D13/22—Servicing or operating apparatus or multistep processes

Definitions

  • the present invention relates to a method for the anti-corrosion pretreatment of a large number of components in series, in which each component in the series at least partially has surfaces of the metals zinc, iron and/or aluminum and undergoes a process step for zinc phosphating and is thereby brought into contact with an acidic aqueous composition to which such an amount of an activating aid has been added that is sufficient to ensure a coating weight of less than 5.5 g/m 2 on a merely cleaned and otherwise untreated hot-dip galvanized steel surface (Z).
  • the activating aid is based on a water-dispersed, particulate component which is at least partially selected from hopeite, phosphophyllite, scholzite and/or hureaulite, and at least one polymeric organic compound.
  • an acidic, aqueous composition for zinc phosphating is included, which is obtainable by adding a certain amount of a colloidal, aqueous solution containing the dispersed, particulate component to an acidic, aqueous composition containing zinc ions, phosphate ions and free fluoride.
  • the layer-forming phosphating is a process that has been practiced and intensively studied for decades for the application of crystalline anti-corrosion coatings on metallic surfaces, in particular on materials made of the metals iron, zinc and aluminium.
  • Zinc phosphating which is particularly well-established for corrosion protection, takes place in a layer thickness of a few micrometers and is based on corrosive pickling of the metallic material in an acidic, aqueous composition containing zinc ions and phosphates. In the course of pickling, an alkaline diffusion layer forms on the metal surface, which extends into the interior of the solution and within which poorly soluble crystallites form, which precipitate directly at the interface with the metallic material and continue to grow there.
  • Water-soluble compounds which represent a source of fluoride ions, are often added to support the pickling reaction on materials made of the metal aluminum and to mask the bath poison aluminum, which in dissolved form interferes with the formation of layers on materials made of the metal.
  • the zinc phosphating is adjusted in such a way that homogeneous, closed and compact crystalline coatings are achieved on the surfaces of the metals iron, zinc and aluminium. Otherwise, good corrosion protection and paint primer cannot be achieved. Homogeneous, closed coatings in zinc phosphating are usually reliably achieved from a layer weight of 2 g/m 2 .
  • the pickling described above and the concentration of the active components in the zinc phosphating stage must be adjusted accordingly in order to ensure correspondingly high layer weights on the surfaces of the metals iron or steel, zinc and aluminum.
  • the zinc phosphating in the prior art is always initiated with an activation of the metallic surfaces of the component to be phosphated.
  • Activation is usually a wet-chemical process step that is conventionally brought into contact with colloidal, aqueous solutions of phosphates ("activation stage"), which are immobilized on the metal surface in the subsequent phosphating as a growth nucleus for the formation of the crystalline coating inside serve the alkaline diffusion layer, so that a high Causes a number density of growing crystallites and thus in turn a compact crystalline zinc phosphate layer is generated, which has excellent corrosion protection and, due to its high electrical penetration resistance, also excellent electrocoating properties.
  • Suitable dispersions are colloidal, mostly neutral to alkaline, aqueous compositions based on phosphate crystallites which, in their crystal structure, exhibit only slight crystallographic deviations from the type of zinc phosphate layer to be deposited.
  • WO 98/39498 A1 teaches in particular divalent and trivalent phosphates of the metals Zn, Fe, Mn, Ni, Co, Ca and Al, with phosphates of the metal zinc preferably being used for activation for subsequent zinc phosphating.
  • An activation stage based on dispersions of bi- and trivalent phosphates requires a high level of process control in order to keep the activation performance constantly at an optimal level, especially when treating a series of metallic components.
  • aqueous solution must lead to a deterioration in the activation performance.
  • a deterioration is initially noticeable in increasing layer weights in the subsequent phosphating and finally leads to the formation of defective or inhomogeneous or less compact phosphate layers.
  • the layer-forming zinc phosphating with upstream activation is therefore a multi-stage process that is complex to control in terms of process technology, which has also been resource-intensive to date, both in terms of the process chemicals and the energy to be expended.
  • WO 2019/238573 A1 addresses a resource-saving method for zinc phosphating and indirectly also a reduction in the complexity of the multi-stage method by presenting a particularly effective activation based on specifically dispersed bi- and trivalent phosphates, which is a colloidal, aqueous which is excellently stabilized against sedimentation
  • a particularly effective activation based on specifically dispersed bi- and trivalent phosphates which is a colloidal, aqueous which is excellently stabilized against sedimentation
  • this complex profile of requirements can be met by maintaining the activation capacity of a pretreatment line for zinc phosphating by metering in an activating aid to the wet-chemical treatment stage of zinc phosphating.
  • This makes it possible, at least partially or entirely, to dispense with an activation stage upstream of the wet-chemical treatment stage of zinc phosphating and in this way to conduct the overall process of zinc phosphating in a way that is less material and energy-intensive and at the same time to reduce procedural complexity in the form of the separate ones that have been absolutely necessary in the prior art decrease activation level.
  • the present invention therefore relates to a method for the anti-corrosion pretreatment of a large number of components in series, in which each component in the series at least partially has surfaces of the metals zinc, iron and/or aluminum and undergoes a process step for zinc phosphating and is treated with an acidic aqueous composition in Is brought into contact with the acidic aqueous composition
  • (C) contains free fluoride and has a free acid in points greater than zero
  • the acidic aqueous composition in the zinc phosphating process step is added continuously or intermittently such an amount of an activation aid (D) that is sufficient under the selected conditions of the zinc phosphating process step, the property of the acidic aqueous composition, on a hot-dip galvanized steel surface (Z) a zinc phosphate layer with a layer weight of less than 5.5 g/m 2 , preferably less than 5.0 g/m 2 , particularly preferably less than 4.5 g/m 2 , to be maintained, the activation aid (D) having a particulate Constituent (a) in water-dispersed form, which contains at least one particulate inorganic compound (a1) composed of phosphates of polyvalent metal cations at least partially selected from hopeite, phosphophyllite, scholzite and/or hureaulite, and at least one polymeric organic compound ( a2) includes.
  • a pretreatment in series is when the components of the series each go through a process step for zinc phosphating according to the method according to the invention and are brought into contact with at least one bath liquid for zinc phosphating provided in a system tank, the individual components being brought into contact one after the other and is therefore separated in time.
  • the system tank is the container in which the acidic aqueous composition is located for the purpose of zinc phosphating by means of a wet-chemical pre-treatment.
  • the components can be brought into contact with the bath liquid of the system tank inside the system tank, for example by immersion, or outside of the system tank, for example by spraying or spraying on the bath solution stored in the system tank.
  • the components treated according to the present invention can be any three-dimensional structure of any shape and design that originates from a manufacturing process, in particular semi-finished products such as strips, sheet metal, rods, pipes, etc. and composite structures assembled from the aforementioned semi-finished products, the semi-finished products preferably being assembled by gluing, Welding and / or flanging are connected to the composite structure.
  • semi-finished products such as strips, sheet metal, rods, pipes, etc.
  • composite structures assembled from the aforementioned semi-finished products the semi-finished products preferably being assembled by gluing, Welding and / or flanging are connected to the composite structure.
  • a component then has at least one surface of the metals zinc, iron and/or aluminum if the metallic structure on this surface is composed of more than 50 at.% of one of the aforementioned metals up to a material penetration depth of at least one micrometer.
  • the inventive property of the acidic aqueous composition for zinc phosphating on hot-dip galvanized steel surfaces is the growth of a zinc phosphate layer with a layer weight below 5.5 g/m 2 , preferably below 5.0 g/m 2 , particularly preferably below 4.5 g/m 2 (hereinafter referred to as "phosphating quality") is to be checked on merely cleaned and degreased (Z) substrates which are not subjected to any further wet-chemical pretreatment step before being brought into contact with the acidic aqueous composition of the method according to the invention.
  • phosphating quality a zinc phosphate layer with a layer weight below 5.5 g/m 2 , preferably below 5.0 g/m 2 , particularly preferably below 4.5 g/m 2
  • hot-dip galvanized steel (Z) is first prepared with an alkaline cleaner as 2% by weight Bonderite® C-AK 1565 A and 0.2% by weight Bonderite® C-AD 1270 in deionized water (K ⁇ 1 Scm -1 ) at pH 11.0 and 55 °C for 5 minutes in immersion.
  • the thus cleaned and degreased (Z) substrates are rinsed at room temperature with deionized water (K ⁇ 1 Scm -1 ) and then fed to the process step of zinc phosphating in accordance with the selected process according to the invention.
  • Corresponding to the selected method according to the invention means at identical temperature, application time and bath circulation and using the acidic aqueous composition for which the phosphating quality specified according to the invention should apply, ie the resulting target layer weights on hot-dip galvanized steel (Z) below 5.5 g/m 2 , preferably below 5.0 g/m 2 , particularly preferably below 4.5 g/m 2 .
  • the phosphating quality can therefore be determined in the current process according to the invention by also introducing cleaned and degreased sheets of hot-dip galvanized steel (Z) for the zinc phosphating process step with the components of the series, and then the layer weight of zinc phosphate on the sheets and thus the Phosphating quality of the acidic aqueous composition for zinc phosphating is determined in the method according to the invention.
  • the cleaned and degreased sheets are of hot dip galvanized steel (Z) rigidly connected to the component or the conveyor frame in their function as test sheets for determining the phosphating quality in order to reproduce the flow conditions during transport of the component together with the conveyor frame through the phosphating bath as well as possible for the test sheet.
  • the sample sheets should ideally be connected to the component or the conveyor frame in such a way that the transport of a sample sheet together with the component and the conveyor frame does not have any influence on the flow conditions to be considered compared to the transport of the component and the conveyor frame without such a sample sheet and that the flow conditions are essentially identical in both cases and thus essentially correspond to the flow conditions of at least a partial area of the components of the series.
  • This can be achieved, for example, by adapting the size and/or the shape of the sample sheet to the size and shape of the component and/or the conveyor frame which is arranged adjacent to the sample sheet in each case.
  • test sheet metal is arranged on an outer surface section of the component or the conveyor frame, to dimension the test component correspondingly smaller than said surface section, for example to prevent the test component from protruding beyond the surface section.
  • sample component can follow a curvature or other planar deviation of the surface section or the conveyor frame. It has proven to be particularly useful to select a sheet metal section that is sufficiently small compared to the size of a suitable outer surface of the component, with an outer surface being particularly suitable if it is located at a location of the component that is particularly small or at the location of the smallest curvature and the test sheet metal is then mounted spaced apart substantially parallel along the surface normal of such an outer surface.
  • the phosphating quality it is also preferred for the phosphating quality that if the contacting is extended by one minute, the layer weight on hot-dip galvanized steel (Z) increases by no more than 0.2 g/m 2 and thus the layer formation under the selected conditions is already in the range of self-limitation, so that the property of the acidic, aqueous composition for zinc phosphating is guaranteed to produce compact, crystalline zinc phosphate layers in the method according to the invention.
  • an amount of an activation aid (D) is added that is sufficient under the selected conditions of the zinc phosphating process step in the process according to the invention, the property of the acidic aqueous composition, on a hot-dip galvanized steel surface (Z) to deposit a zinc phosphate layer with a layer weight of less than 5.5 g/m 2 , preferably less than 5.0 g/m 2 , particularly preferably less than 4.5 g/m 2 , with the under the selected conditions of the process step of zinc phosphating in the process according to the invention does not increase by more than 0.2 g/m 2 when the contact time with the acidic, aqueous composition is extended by 60 seconds.
  • an activation aid (D) is added that is sufficient under the selected conditions of the zinc phosphating process step in the process according to the invention, the property of the acidic aqueous composition, on a hot-dip galvanized steel surface (Z) to deposit a zinc phosphate layer with a layer weight of less than 5.5 g/m 2
  • the phosphating quality is determined and monitored in the method according to the invention, in that hot-dip galvanized steel (Z), which has been cleaned and degreased as described above, also undergoes the zinc phosphating process step at regular intervals during the series treatment and is then subjected to a coating weight determination.
  • hot-dip galvanized steel (Z) which has been cleaned and degreased as described above, also undergoes the zinc phosphating process step at regular intervals during the series treatment and is then subjected to a coating weight determination.
  • the phosphating quality of the acidic, aqueous composition is ensured by metering in the activating agent (D), homogeneous, closed and compact crystalline zinc phosphate coatings are deposited on the components that have the surfaces of the metals zinc, iron and aluminum in the usual treatment times of 20 seconds to 5 minutes.
  • the layer weight of zinc phosphate is determined in the context of the present invention by detaching the zinc phosphate layer with aqueous 5% by weight CrO 3 as a pickling solution immediately after zinc phosphating and rinsing with deionized water (K ⁇ 1 Scm -1 ) at 25 ° C is brought into contact with a defined area of the phosphated material or component for 5 min and subsequent determination of the phosphorus content in the same pickling solution with ICP-OES.
  • the layer weight of zinc phosphate results from multiplying the surface-related amount of phosphorus by a factor of 6.23.
  • the activating aid (D) is added to the acidic aqueous composition for zinc phosphating for the purpose of maintaining the phosphating quality in the zinc phosphating process step.
  • it can be added by continuous or discontinuous dosing into the system tank. Continuous dosing is preferred when the pretreatment of the components in series follows immediately after one another and the decrease in the phosphating quality can be determined over time, so that a quantity of the activating agent can be continuously added over time.
  • This method has the advantage that the phosphating quality does not have to be checked further after the start-up of the pre-treatment line and the determination of the material flows for dosing the activating agent and other active components, as long as the series treatment remains unchanged in terms of timing and condition of the components to be treated and the treatment parameters in the zinc phosphating process step remains.
  • discontinuous dosing of the activation aid is advantageous and may even be indicated.
  • the phosphating quality of the acidic aqueous composition is preferably monitored continuously or at defined time intervals and then a specified amount of the activation aid is metered in if the layer weight on hot-dip galvanized steel (Z) is a certain value below 5.5 g/m 2 , preferably below of 5.0 g/m 2 , particularly preferably below 4.5 g/m 2 .
  • the continuous or quasi-continuous determination of the phosphating quality, which takes place at defined time intervals, can also be carried out using proxy data that correlate with the actual zinc phosphate layer weight.
  • the non-destructive determination of the layer thickness provides suitable proxy data for the layer weight of zinc phosphate, which is reliably measured on the components in a pre-treatment line and with the actual layer weight on the hot-dip galvanized parts Steel (Z) can be correlated.
  • the crystallite size and thus the determination of the roughness by means of optical profilometry can also provide proxy data for the layer weight, since a higher layer weight on hot-dip galvanized steel (Z) is associated with a low number density of crystallites, which, however, are relatively larger, so that the roughness with the layer weight increases.
  • the phosphating quality is already adequate in most cases if the activation aid (D) is metered in continuously or discontinuously in such an amount that is suitable, a stationary amount of preferably at least 0.001 g/kg, particularly preferably to maintain at least 0.005 g/kg, particularly preferably at least 0.01 g/kg, of particulate component (a) in the acidic aqueous composition during the pretreatment of the components in series.
  • the present invention thus shows in a surprising way that by metering in an activation aid, as is known in the prior art and is described, for example, in WO 98/39498 A1, activation of the metal surfaces can take place directly in the acidic, aqueous treatment solution for zinc phosphating. so that homogeneous, closed and compact crystalline zinc phosphate coatings with high electrical resistance grow on the metal surfaces.
  • the present invention makes use of this effect by focusing on maintaining the phosphating quality in the series treatment of components by metering in the activating aid to the acidic, aqueous composition for zinc phosphating.
  • the components of the series are not activated with a colloidal, aqueous solution containing hopeite, phosphophyllite, scholzite and/or in the particulate component before being brought into contact with the acidic aqueous composition in the zinc phosphating process step Hureaulite, preferably phosphates of polyvalent metal cations, or sparingly soluble salts of the element Ti brought into contact.
  • the components of the series are particularly preferably not brought into contact with any colloidal, aqueous solution to activate the surfaces of the components for zinc phosphating before they are brought into contact with the acidic aqueous composition in the zinc phosphating process step, and the components of the series are very particularly preferably passed through no activation step prior to contacting to activate the surfaces of the components for zinc phosphating.
  • a cleaning and degreasing step cannot usually be dispensed with.
  • at least the metallic surfaces of the components are cleaned and optionally degreased in a cleaning step before the zinc phosphating step.
  • the cleaning is preferably carried out by bringing it into contact with an aqueous, preferably neutral or alkaline cleaning agent, the process step of zinc phosphating preferably immediately following the cleaning step with or without an intermediate rinsing step.
  • the alkaline cleaning is characterized by the fact that the metal surfaces, in particular the surfaces that contain metallic aluminum, whether as a material or as an alloy component of hot-dip galvanized steel, are pickled, which leads to an additional standardization of the metal surfaces and is therefore advantageous for the Growth of homogeneous zinc phosphate coatings.
  • the cleaning stage is preferably not carried out by bringing it into contact with an aqueous, preferably neutral or alkaline cleaner containing a particulate component comprising hopeite, phosphophyllite, scholzite and/or hureaulite or poorly soluble salts of the element Ti, since, as explained above, any activation of the metal surfaces before the zinc phosphating can be dispensed with according to the invention.
  • an aqueous, preferably neutral or alkaline cleaner containing a particulate component comprising hopeite, phosphophyllite, scholzite and/or hureaulite or poorly soluble salts of the element Ti, since, as explained above, any activation of the metal surfaces before the zinc phosphating can be dispensed with according to the invention.
  • a rinsing step after cleaning is optional and, in the context of the present invention, is used exclusively for the complete or partial removal of soluble residues, particles and active components that are carried over from a previous wet-chemical treatment step - here the cleaning and degreasing step - adhering to the component , from the component to be treated, without the rinsing liquid itself containing active components based on metallic or semi-metallic elements, which are consumed simply by bringing the metallic surfaces of the component into contact with the rinsing liquid.
  • the rinsing liquid can only be city water or deionized water or, if necessary, it can also be a rinsing liquid which contains surface-active compounds to improve the wettability with the rinsing liquid.
  • the phosphating quality in the method according to the invention on hot-dip galvanized steel is technically optimized, methods are naturally also preferred according to the invention in which the components of the series at least partially have surfaces of the metal zinc, which are in particular selected from surfaces of hot-dip galvanized steel.
  • the phosphating quality of the acidic, aqueous composition, which is maintained in the process according to the invention by adding the activating agent (D), is such that components that are made of multi-metal construction, such as automobile bodies, can also be zinc-phosphated with very good properties and very homogeneous, closed and compact zinc phosphate coatings are also accessible on the surfaces of iron and aluminum.
  • the components in the series also have surfaces made of the metal iron or, specifically for lightweight construction in bodywork production, additional aluminum.
  • the components have surfaces of the metals zinc, iron and aluminum next to one another.
  • the components are brought into contact with the acidic, aqueous composition for at least a period of time sufficient to deposit a layer weight of at least 1.0 g/m 2 on the zinc surfaces , since it is then ensured that a sufficiently homogeneous, closed zinc phosphate coating is formed on all metal surfaces of the components selected from zinc, iron and aluminum. Accordingly, preference is given to a method according to the invention in which a zinc phosphate layer with a layer weight of at least 1.0 g/m 2 , preferably at least 1.5 g/m 2 , is deposited on the surfaces of zinc.
  • the layer weight of the zinc phosphate layer on the zinc surfaces of the component is preferably below 5.5 g/m 2 , preferably below 5.0 g/m 2 and particularly preferably below 4.5 g / m 2 lies.
  • Activating aids (D) which can be used according to the invention, i.e. which maintain the phosphating quality when added to the acidic, aqueous composition of the zinc phosphating, are aqueous dispersions and thus contain a particulate component (a) in water-dispersed form which contains at least one particulate inorganic compound ( a1) composed of phosphates of polyvalent metal cations at least partially selected from hopeite, phosphophyllite, scholzite and/or hureaulite, and at least one polymeric organic compound (a2).
  • the proportion of phosphates contained in the at least one particulate inorganic compound (a1) based on the dispersed particulate component (a) in the activation aid is preferably at least 25% by weight, particularly preferably at least 35% by weight, particularly preferably at least 40% by weight %, most preferably at least 45% by weight.
  • the dispersed particulate component (a) of the activation aid (D) is the solids content that remains after drying the retentate of an ultrafiltration of a defined partial volume of the activation aid (D) with a nominal exclusion limit of 10 kD (NMWC, Nominal Molecular Weight Cut Off).
  • the ultrafiltration is carried out with the supply of deionized water (K ⁇ I Scrm 1 ) until a conductivity below 10 pScm -1 is measured in the filtrate.
  • the inorganic particulate component in the activation aid (D) is in turn that which remains when the particulate component (a) obtained from the drying of the retentate of the ultrafiltration is heated in a reaction furnace with the supply of a CO2-free stream of oxygen at 900 °C without the admixture of catalysts or other additives is pyrolyzed until an infrared sensor in the outlet of the reaction furnace delivers a signal identical to the CO2-free carrier gas (blank value).
  • the phosphates contained in the inorganic particulate component are determined directly from the acid digestion as the phosphorus content by means of atomic emission spectrometry (ICP-OES) after acid digestion of the same with aqueous 10% by weight HNO3 solution at 25 °C for 15 min.
  • ICP-OES atomic emission spectrometry
  • the active components of the activation aid (D), which - as soon as they are added in sufficient quantities to the acidic aqueous composition for zinc phosphating - promote the formation of a homogeneous, closed and compact crystalline phosphate coating on the metal surfaces and in this sense activate the metal surfaces, are as already mentioned composed primarily of phosphates, which in turn are at least partially selected from hopeite, phosphophyllite, scholzite and/or hureaulite, preferably at least partially selected from hopeite, phosphophyllite and/or scholzite, particularly preferably at least partially selected from hopeite and/or phosphophyllite and very particularly preferably at least are partially selected from Hopeit.
  • the maintenance of the phosphating quality in the acidic, aqueous composition is therefore essentially based on the metered-in phosphates in particulate form contained in the activation auxiliary (D).
  • hopeites include stoichiometric Zns(PO4)2 as well as the variants Zn2Mn(PO4)s containing nickel and manganese, Zri2Ni(PO4)3, whereas phosphophyllite consists of Zn2Fe(PC>4)3, scholzite of Zn2Ca(PC>4)3 and hureaulite of Mn 3 (PC>4)2.
  • the existence of the crystalline phases hopeite, phosphophyllite, scholzite and/or hureaulite in the activation aid (D) can be determined after the particulate component (a) has been separated off by means of ultrafiltration with a nominal exclusion limit of 10 kD (NM WC, Nominal Molecular Weight Cut Off) as described above and drying of the retentate to constant mass at 105°C using X-ray diffractometric methods (XRD).
  • NM WC Nominal Molecular Weight Cut Off
  • the activation aid (D) at least 20% by weight, particularly preferably at least 30% by weight, particularly preferably at least 40% by weight, of zinc are contained in the inorganic particulate component, based on the phosphate content of the inorganic particulate component, calculated as PO4.
  • the activation aid (D) should preferably not additionally contain any titanium phosphates, since these do not have a positive effect on the phosphating quality when metered in.
  • the proportion of titanium in the inorganic particulate component of the activation aid (D) is less than 0.01% by weight, particularly preferably less than 0.001% by weight, based on the activation aid (D).
  • the activation aid (D) contains a total of less than 10 mg/kg, particularly preferably less than 1 mg/kg, of titanium.
  • the polymeric organic compound (a2) which stabilizes the particulate component exerts a major influence on the effectiveness of the particulate component (a) metered in via the activation auxiliary (D). It turns out that the selection of the polymeric organic compound is decisive for the degree of activation of the metal surfaces in the acidic aqueous zinc phosphating composition, which is known to be brought about by the dispersed polyvalent phosphates and which, as the present invention shows, surprisingly also occurs simultaneously with the layer formation can take place.
  • an organic compound is polymeric if its weight-average molar mass is greater than 500 g/mol.
  • the molar mass is determined using the molar mass distribution curve of a sample of the respective reference variable, which is determined experimentally at 30° C. using size exclusion chromatography with a concentration-dependent refractive index detector and is calibrated against polyethylene glycol standards.
  • the average molar mass values are evaluated computer-aided using the strip method with a third-order calibration curve.
  • Hydroxylated polymethacrylate is suitable as column material and an aqueous solution of 0.2 mol/L sodium chloride, 0.02 mol/L sodium hydroxide, 6.5 mmol/L ammonium hydroxide is suitable as eluent.
  • the maintenance of the phosphating quality and thus activation of the metal surfaces in the process step of zinc phosphating when brought into contact with the acidic aqueous composition is particularly successful, ie using relatively small amounts of active components of the activating aid (D), if the polymeric organic compound (a2) used to disperse the particulate inorganic compound (a1) is at least partly composed of styrene and/or an ⁇ -olefin having not more than 5 carbon atoms, the polymeric organic compound (a2) additionally having units of maleic acid, its anhydride and/or its imide and preferably additionally polyoxyalkylene units, particularly preferably polyoxyalkylene units, in its side chains.
  • Such polymeric organic compounds (a2) are therefore preferred according to the invention in the particulate component (a) of the activation aid.
  • the ⁇ -olefin is preferably selected from ethene, 1-propene, 1-butene, isobutylene, 1-pentene, 2-methylbut-1-ene and/or 3-methylbut-1-ene and particularly preferably selected from isobutylene. It is clear to the person skilled in the art that the polymeric organic compounds (a2) contain these monomers as structural units in unsaturated form covalently linked to one another or to other structural units.
  • polymeric organic compounds (a2) examples include Dispex® CX 4320 (BASF SE), a maleic acid-isobutylene copolymer modified with polypropylene glycol, Tego® Dispers 752 W (Evonik Industries AG), a maleic acid-styrene copolymer modified with polyethylene glycol, or Edaplan® 490 (Münzing Chemie GmbH) a maleic acid-styrene copolymer modified with EO/PO and imidazole units.
  • the polymeric organic compounds (a2) used for the colloidal stabilization of the particulate component (a) of the activation aid (D) preferably have polyoxyalkylene units, which in turn are preferably made up of 1,2-ethanediol and/or 1,2-propanediol, in particular preferably of both 1,2-ethanediol and 1,2-propanediol, the proportion of 1,2-propanediols in the total of the polyoxyalkylene units preferably being at least 15% by weight, but particularly preferably 40% by weight based on the total of the polyoxyalkylene units.
  • the polyoxyalkylene units are preferably contained in the side chains of the polymeric organic compounds (a2).
  • the organic polymeric compounds (a2) also have imidazole units, preferably such that the polyoxyalkylene units of the polymeric organic compounds (a2) at least partially end-capped with an imidazole group, so that in the preferred embodiment terminal imidazole groups are present in the polyoxyalkylene side chain, the polyoxyalkylene units being covalently linked to the imidazole group preferably via a nitrogen atom of the heterocycle.
  • the amine number of the organic polymeric compounds (a2) is at least 25 mg KOH/g, particularly preferably at least 40 mg KOH/g, but preferably less than 125 mg KOH/g, particularly preferably less than 80 mg KOH / g, so that in a preferred embodiment all of the polymeric organic compounds in the particulate component (a) of the activating aid have these preferred amine numbers.
  • the amine number is determined based on a weight of approximately 1 g of the respective reference value - organic polymeric compounds (a2) or all of the polymeric organic compounds in the particulate component (a) - in 100 ml of ethanol, with 0.1 N HCl standard solution against the indicator bromophenol blue until the color changes to yellow at a temperature of the ethanolic solution of 20 °C is titrated.
  • the amount of standard HCl solution consumed in milliliters multiplied by the factor 5.61 divided by the exact mass of the sample in grams corresponds to the amine number in milligrams of KOH per gram of the respective reference value.
  • the polymeric organic compounds (a2) preferably also all of the polymeric organic compounds in the particulate component (a), have an acid number according to DGF CV 2 (06) (as of April 2018) of at least 25 mg KOH/g, but preferably less than 100 mg KOH/g, more preferably less than 70 mg KOH/g to ensure a sufficient number of polyoxyalkylene units.
  • the polymeric organic compounds (a2) preferably also all of the polymeric organic compounds in the particulate component (a), have a hydroxyl number of less than 15 mg KOH/g, particularly preferably less than 12 mg KOH/g, particularly preferably less than 10 mg KOH/g, determined in each case according to method A of 01/2008:20503 from European Pharmacopoeia 9.0.
  • the proportion of the polymeric organic compounds (a2), preferably all of the polymeric organic compounds in the particulate component (a), based on the particulate component (a) is at least 3% by weight, more preferably at least 6% by weight, but preferably does not exceed 15% by weight.
  • the dispersed particulate component (a) of the activation aid (D) is the solids content that remains after drying the retentate of an ultrafiltration of a defined partial volume of the activation aid (D) with a nominal exclusion limit of 10 kD (NMWC, Nominal Molecular Weight Cut Off). The ultrafiltration is carried out with the supply of deionized water (K ⁇ I Scrm 1 ) until a conductivity below 10 pScm -1 is measured in the filtrate.
  • the activation aid (D) preferably contains no more than 40% by weight of particulate component (a) based on the agent, otherwise the stability of the dispersion and the procedural manageability for continuous or discontinuous metering of the agent to the acidic aqueous composition of the zinc phosphating using dosing pumps is no longer guaranteed or at least expensive. This applies in particular with regard to the overall low amounts of particulate constituents (a) required to maintain the phosphating quality of a reference amount of the acidic aqueous composition for zinc phosphating. On the other hand, it is advantageous if the activation aid is provided as a dispersion which is as stable as possible and at the same time as highly concentrated as possible.
  • activation aids (D) which contain at least 5% by weight, but preferably not more than 30% by weight % of particulate component (a) based on the composition.
  • the activation aid (D) can in the process according to the invention also have a D50 value of be characterized more than 10 pm, which is correspondingly preferred.
  • the agglomerates of the dispersed particles contained in the dispersion cause the thixotropic flow properties, which are favorable for the activating aid (D) to be able to be handled.
  • the tendency of the agglomerates to be highly viscous at low shear favors their long shelf life, while the loss of viscosity at shear conditions their pumpability.
  • a D90 value for the aqueous dispersion of less than 150 ⁇ m, preferably less than 100 ⁇ m, in particular less than 80 ⁇ m, is preferred is.
  • the D50 value or the D90 value denotes the particle diameter which 50% by volume or 90% by volume, respectively, of the particulate components present in the aqueous dispersion do not exceed.
  • the particle size distribution is measured within 120 seconds of adding the dispersion to the dilution volume.
  • the presence of a thickener can be advantageous for preventing the irreversible agglomeration of primary particles of the particulate component (a), particularly when the activation aid (D) is present as the concentrated dispersion described above.
  • the activating aid (D) contains a thickener, preferably in an amount which gives the activating aid (D) a maximum dynamic viscosity at a temperature of 25° C. in the shear rate range from 0.001 to 0.25 reciprocal seconds at least 1000 Pa s, but preferably below 5000 Pa s, and preferably leads to shear-thinning behavior at 25° C., i.e.
  • the viscosity over the specified shear rate range can be determined using a plate/cone viscometer with a cone diameter of 35 mm and a gap width of 0.047 mm.
  • K ⁇ 1 pScm -1 deionized water
  • the activation aid (D) preferably contains a total of at least 0.5% by weight, but preferably not more than 4% by weight, particularly preferably not more than 3% by weight, of one or more thickeners, with the total proportion still preferably being polymers organic compounds in the non-particulate component of the aqueous dispersion 4% by weight (based on the dispersion) does not exceed.
  • the non-particulate component is the solids content of the aqueous dispersion in the permeate of the ultrafiltration already described after it has been dried to constant mass at 105° C.—ie the solids content after the particulate component has been separated off by means of ultrafiltration.
  • the thickener is preferably selected from polymeric organic compounds, which in turn are preferably selected from polysaccharides, cellulose derivatives, aminoplasts, polyvinyl alcohols, polyvinylpyrrolidones, polyurethanes and/or urea urethane resins, and particularly preferably from urea urethane resins, in particular those urea urethane resins which represent a mixture of polymeric compounds resulting from the reaction of a polyfunctional isocyanate with a polyol and a mono- and/or diamine.
  • the urea urethane resin is derived from a polyhydric isocyanate, preferably selected from 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2(4),4-trimethyl-1,6-hexamethylene diisocyanate, 1,10- Decamethylene diisocyanate, 1,4'-cyclohexylene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate and mixtures thereof, p- and m-xylylene diisocyanate, and 4-4'-diisocyanatodicyclohexylmethane, particularly preferably selected from 2,4-toluene diisocyanate and/or m-xylylene diisocyanate.
  • a polyhydric isocyanate preferably selected from 1,4-te
  • the urea-urethane resin is derived from a polyol selected from polyoxyalkylene diols, particularly preferably from polyoxyethylene glycols, which in turn are preferably composed of at least 6, particularly preferably at least 8, particularly preferably at least 10, but preferably less than 26, particularly preferably less than 23 oxyalkylene units.
  • urea urethane resins are obtainable by a first reaction of a diisocyanate, such as toluene-2,4-diisocyanate, with a polyol, such as a polyethylene glycol, to form NCO-terminated urethane prepolymers, after which with a primary monoamine and / or with a primary diamine, for example m-xylylenediamine, is further implemented.
  • a diisocyanate such as toluene-2,4-diisocyanate
  • a polyol such as a polyethylene glycol
  • NCO-terminated urethane prepolymers after which with a primary monoamine and / or with a primary diamine, for example m-xylylenediamine, is further implemented.
  • Particular preference is given to urea-urethane resins which have neither free nor blocked isocyanate groups.
  • urea-urethane resins promote the formation of loose agglomerates of primary particles, which are protected against further agglomeration and, when metered into the acidic, aqueous composition for zinc phosphating, dissociate into primary particles.
  • urea-urethane resins are preferably used as thickeners, which have neither free or blocked isocyanate groups nor terminal amine groups.
  • the thickener which is a urea urethane resin, therefore has an amine number of less than 8 mg KOH/g, particularly preferably less than 5 mg KOH/g, particularly preferably less than 2 mg KOH/g, determined in each case according to the method as described above for the organic polymeric compound (a2).
  • an activation aid is accordingly preferred in which the The totality of the polymeric organic compounds in the non-particulate component preferably has an amine number of less than 16 mg KOH/g, particularly preferably less than 10 mg KOH/g, particularly preferably less than 4 mg KOH/g.
  • the urea-urethane resin has a hydroxyl number in the range from 10 to 100 mg KOH/g, particularly preferably in the range from 20 to 60 mg KOH/g, determined according to method A of 01/2008:20503 from European Pharmacopoeia 9.0. having.
  • a weight-average molar mass of the urea-urethane resin in the range from 1000 to 10000 g/mol, preferably in the range from 2000 to 6000 g/mol is advantageous according to the invention and therefore preferred, in each case determined experimentally as before in connection with the inventive definition of a polymeric organic connection described.
  • the activating aid (D) is an aqueous dispersion which preferably has a pH in the range from 6.5-8.0 and particularly preferably no pH-regulating, water-soluble compounds with a pKa value of less than 6 or pKa value of contains less than 5.
  • the activating aid (D) can also contain other auxiliaries, for example selected from preservatives, wetting agents and defoamers, which are present in the amount required for the particular function.
  • the proportion of auxiliaries, particularly preferably other compounds in the non-particulate component that are not thickeners, is preferably less than 1% by weight.
  • the activation aid (D) is preferably obtainable as a concentrated aqueous dispersion i) providing a pigment paste by triturating 10 parts by mass of an inorganic particulate compound (a1) with 0.5 to 2 parts by mass of the polymeric organic compound (a2) in the presence of 4 to 7 parts by mass of water and grinding until a D50 value of less is reached determined as 1 ⁇ m by means of dynamic light scattering after dilution with water by a factor of 1000, for example using Zetasizer® Nano ZS, from Malvern Panalytical GmbH; ii) Diluting the pigment paste with such an amount of water, preferably deionized water (K ⁇ 1 Scm -1 ) or process water, and a thickener that a dispersed particulate component (a) of at least 5% by weight and a maximum dynamic viscosity of at least 1000 Pa s at a temperature of 25 ° C in the shear rate range of 0.001 to 0.25 reciprocal seconds, preferred embodiments of the activ
  • (C) contains free fluoride and has a free acid in points greater than zero.
  • the amount of phosphate ions includes orthophosphoric acid and the anions of the salts of orthophosphoric acid dissolved in water, calculated as PO4.
  • the proportion of the free acid in points is preferably at least 0.4 in the acidic aqueous composition of the zinc phosphating of the process according to the invention, but preferably no more than 3.0, more preferably no more than 2.0.
  • the percentage of free acid in points is determined by diluting a 10 ml sample volume of the acidic aqueous composition to 60 ml and titrating with 0.1 N sodium hydroxide solution to pH 3.6. The consumption of ml of sodium hydroxide indicates the number of free acid points.
  • the preferred pH of the acidic aqueous composition is usually above 2.5, particularly preferably above 2.7, but preferably below 3.5, particularly preferably below 3.3.
  • the "pH value" corresponds to the negative decadic logarithm of the hydronium ion activity at 20° C. and can be determined using pH-sensitive glass electrodes.
  • a quantity of free fluoride or a source of free fluoride ions is essential for the zinc phosphating layer forming process.
  • components including surfaces of zinc and surfaces of iron or aluminum are to be zinc-phosphated in a layer-forming manner, as is necessary, for example, in the zinc phosphating of automobile bodies that are at least partially made of aluminum, it is advantageous if the amount of free fluoride in of the acidic aqueous composition is at least 0.5 mmol/kg, particularly preferably at least 2 mmol/kg.
  • the concentration of free fluoride should not exceed values above which the phosphate coatings have loose adhesions that can be easily wiped off, since this defect can also be caused by an increased dosage of activation aid (D) or by an increased stationary amount of particulate components (a) in of the acidic aqueous composition for zinc phosphating often cannot be compensated. It is therefore advantageous and therefore preferred if the concentration of free fluoride in the acidic aqueous composition of the zinc phosphating is below 15 mmol/kg, particularly preferably below 10 mmol/kg and particularly preferably below 8 mmol/kg in the method according to the invention.
  • the amount of free fluoride is to be determined potentiometrically at 20 °C in the respective acidic aqueous composition after calibration with fluoride-containing buffer solutions without pH buffering using a fluoride-sensitive measuring electrode.
  • Suitable sources for free fluoride ions are hydrofluoric acid and its water-soluble salts, such as ammonium bifluoride and sodium fluoride, and complex fluorides of the elements Zr, Ti and/or Si, in particular complex fluorides of the element Si.
  • the source of free fluoride is in one Phosphating according to the present invention therefore selected from hydrofluoric acid and its water-soluble salts and/or complex fluorides of the elements Zr, Ti and/or Si.
  • Hydrofluoric acid salts are water-soluble in the context of the present invention if their solubility in deionized water (K ⁇ 1 Scm -1 ) at 60° C. is at least 1 g/L calculated as F.
  • the source of free fluoride in such methods according to the invention is at least partially selected from complex fluorides of the element Si, in particular from hexafluorosilicic acid and its salts.
  • complex fluorides of the element Si in particular from hexafluorosilicic acid and its salts.
  • Those skilled in the art of phosphating understand the formation of specks as the phenomenon of local deposition of amorphous, white zinc phosphate in an otherwise crystalline phosphate layer on the treated zinc surfaces or on the treated galvanized or alloy-galvanized steel surfaces.
  • the accelerators known in the prior art can be added to the acidic aqueous composition in the process according to the invention for more rapid layer formation. These are preferably selected from 2-hydroxymethyl-2-nitro-1,3-propanediol, nitroguanidine, N-methylmorpholine-N-oxide, nitrite, hydroxylamine and/or hydrogen peroxide.
  • nitroguanidine or hydroxylamine is used as an accelerator, so that nitroguanidine or Hydroxylamine, in particular nitroguanidine, are particularly preferred as accelerators in the acidic aqueous composition in the process according to the invention with regard to a particularly low substance consumption of the activating aid for maintaining the phosphating quality.
  • an embodiment is particularly preferred in which less than 10 ppm of nickel and/or cobalt ions are contained in the acidic aqueous composition for zinc phosphating in the process according to the invention.
  • the additives known in the art in processes of zinc phosphating can also be used.
  • a good primer for paint adhesion is achieved for a subsequent dip coating or powder coating, in the course of which an essentially organic top coat is applied.
  • the zinc phosphating follows with or without an intermediate rinsing and/or drying step, but preferably with a rinsing step but without a drying step, followed by a dip coating or powder coating, particularly preferably an electro-dip coating, particularly preferably a cathodic electro-dip coating, which preferably in addition to the dispersed resin, which preferably comprises an amine-modified polyepoxide, contains water-soluble or water-dispersible salts of yttrium and/or bismuth.
  • a dip coating or powder coating particularly preferably an electro-dip coating, particularly preferably a cathodic electro-dip coating, which preferably in addition to the dispersed resin, which preferably comprises an amine-modified polyepoxide, contains water-soluble or water-dispersible salts of yttrium and/or bismuth.
  • the present invention relates to an acidic aqueous zinc phosphating composition having a Free Acid in points greater than zero, and
  • a water-dispersed particulate component comprising phosphates of polyvalent metal cations, the phosphates being at least partially selected from hopeite, phosphophyllite, scholzite and/or hureaulite, obtainable by adding an amount of an aqueous dispersion to an acidic aqueous composition containing the components ( A) - (C), wherein the aqueous dispersion contains a particulate component (a) in water-dispersed form, which comprises at least one particulate inorganic compound (a1), which is at least partially selected from phosphates of polyvalent metal cations from hopeite, phosphophyllite, scholzite and /or Hureaulith is composed, and at least one polymeric organic compound (a2), wherein the aqueous dispersion is added in an amount such that the proportion by weight of phosphates from the particulate component of the aqueous dispersion based on the acidic aqueous composition containing the
  • coupons of cold rolled steel (CRS), hot dip galvanized steel (Z), and aluminum (AA6014) were zinc phosphated.
  • the sheets were: a) alkaline cleaned using 2% by weight of Bonderite® C-AK 1565 A mixed with 0.2% by weight of Bonderite® C-AD 1270 (each commercially available cleaner from Henkel AG & Co.
  • KGaA deionized water prepared in deionized water (K ⁇ 1 pScm -1 ); cleaning was carried out by spraying, after setting a pH of 11.0 and a temperature of 55° C., initially for 1 minute at a pressure of 1 bar, then by immersion for 3 minutes with stirring; b) rinsed with deionized water (K ⁇ 1 pScm -1 ) for about 1 minute; c) wetted with water - without further treatment in a separate activation bath - directly in a phosphating bath based on deionized water (K ⁇ 1 pScm -1 ) and 4.6% by weight Bonderite® M-Zn 1994 MU-1, as well as 1 weight % Bonderite® M-AD 565 (each from Henkel AG & Co.
  • Phosphating bath of an activation aid according to the invention based on particulate zinc phosphate was added, which is present in dispersed form with the aid of a styrene-maleic acid copolymer which additionally comprises polyoxyalkylene side chains, so that the proportion of particulate components of the activation aid in the phosphating bath is 0.6 g per liter of the phosphating bath is realized; or c3) 2 g Bonderite® M-AC 50 CF (Henkel AG & Co. KGaA) of a Ti-based
  • Activating aid was added per liter of the phosphating bath; d) subsequently rinsed with deionized water (K ⁇ 1 pScm -1 ) for about 1 minute; e) blown off with compressed air at 20 °C and then dried in an oven at 50 °C. Sheet metal sections of the abovementioned substrates were cleaned according to the scheme described above according to a) to b).
  • Table 1 gives the respective layer weights after going through the process steps and phosphating baths described above. It is found that in method c2 according to the invention, in terms of layer weights and compactness of the zinc phosphate layers, equally good results are achieved on all substrates in the absence of activation prior to the phosphating bath, whereas an activation aid based on particulate titanium phosphates is not suitable for bringing about phosphating under these conditions ( see c3).
  • the blind test c1 again shows that in the absence of an upstream activation stage and without adding additives to the phosphating bath with a suitable activating agent, there is no phosphating of the steel and aluminum surfaces, while very coarse phosphate crystallites grow on hot-dip galvanized steel (Z), so that a high layer weight, but no adequate corrosion protection can be achieved after dip painting.

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Abstract

La présente invention concerne un procédé de prétraitement anticorrosion d'une multitude de composants en série, dans lequel chaque composant de la série comporte au moins partiellement des surfaces des métaux zinc, fer et/ou aluminium et subit une étape de traitement pour la phosphatation du zinc, dans laquelle il est mis en contact avec une composition acide aqueuse à laquelle il a été ajouté une quantité d'un auxiliaire d'activation qui est suffisante pour assurer un poids de couche inférieur à 5,5 g/m2 sur une surface d'acier galvanisé par immersion à chaud (Z) qui a été simplement nettoyée et qui est autrement non traitée. L'auxiliaire d'activation est basé sur un constituant particulaire dispersé dans l'eau au moins partiellement choisi parmi l'hopéite, la phosphophyllite, la scholzite et/ou l'hureaulite, et au moins un composé organique polymère. L'invention concerne en outre une composition aqueuse acide pour la phosphatation du zinc, pouvant être obtenue par ajout d'une quantité particulière d'une solution aqueuse colloïdale contenant le constituant particulaire dispersé à une composition aqueuse acide contenant des ions de zinc, des ions phosphate et du fluorure libre.
PCT/EP2021/073476 2020-09-04 2021-08-25 Procédé en une étape pour la phosphatation du zinc WO2022048963A1 (fr)

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EP21762057.4A EP4208585A1 (fr) 2020-09-04 2021-08-25 Procédé en une étape pour la phosphatation du zinc
MX2023002586A MX2023002586A (es) 2020-09-04 2021-08-25 Proceso de una etapa para la fosfatacion de zinc.
KR1020237007293A KR20230061381A (ko) 2020-09-04 2021-08-25 아연 인산화를 위한 1-단계 공정
JP2023514888A JP2023540976A (ja) 2020-09-04 2021-08-25 リン酸亜鉛化の一段階プロセス
CN202180054117.6A CN116096945A (zh) 2020-09-04 2021-08-25 锌系磷化一步法
US18/174,102 US20230220559A1 (en) 2020-09-04 2023-02-24 One-stage process for zinc phosphating

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EP4411022A1 (fr) 2023-02-02 2024-08-07 Henkel AG & Co. KGaA Traitement en plusieurs étapes pour la phosphatation activée de zinc de composants métalliques

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EP3828307A1 (fr) * 2019-11-26 2021-06-02 Henkel AG & Co. KGaA Procédé économe en ressources permettant d'activer une surface métallique avant une phosphatation
CN114990537B (zh) * 2022-08-04 2022-11-25 山东一立动力科技股份有限公司 一种铝合金表面磷化处理方法

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EP3392376A1 (fr) * 2017-04-21 2018-10-24 Henkel AG & Co. KGaA Procédé formant des couches de phosphatate de zinc sur des composants métalliques en série
WO2018192707A1 (fr) * 2017-04-21 2018-10-25 Henkel Ag & Co. Kgaa Procédé de phosphatation au zinc, filmogène et exempte de boue, d'éléments métalliques en série
WO2019238573A1 (fr) 2018-06-11 2019-12-19 Henkel Ag & Co. Kgaa Dispersion aqueuse pour l'activation d'une surface métallique et son procédé de phosphatation

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WO1998039498A1 (fr) 1997-03-07 1998-09-11 Henkel Corporation Conditionnement de surfaces metalliques prealablement a la phosphatation
WO2001012341A1 (fr) * 1999-08-16 2001-02-22 Henkel Corporation Procede de realisation d'un revetement de conversion a base de phosphate sur du metal
EP3392376A1 (fr) * 2017-04-21 2018-10-24 Henkel AG & Co. KGaA Procédé formant des couches de phosphatate de zinc sur des composants métalliques en série
WO2018192707A1 (fr) * 2017-04-21 2018-10-25 Henkel Ag & Co. Kgaa Procédé de phosphatation au zinc, filmogène et exempte de boue, d'éléments métalliques en série
WO2019238573A1 (fr) 2018-06-11 2019-12-19 Henkel Ag & Co. Kgaa Dispersion aqueuse pour l'activation d'une surface métallique et son procédé de phosphatation

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4411022A1 (fr) 2023-02-02 2024-08-07 Henkel AG & Co. KGaA Traitement en plusieurs étapes pour la phosphatation activée de zinc de composants métalliques
WO2024160449A1 (fr) 2023-02-02 2024-08-08 Henkel Ag & Co. Kgaa Traitement en plusieurs étapes pour la phosphatation au zinc activé de composants métalliques

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EP4208585A1 (fr) 2023-07-12
KR20230061381A (ko) 2023-05-08
EP3964606A1 (fr) 2022-03-09
JP2023540976A (ja) 2023-09-27
MX2023002586A (es) 2023-03-22
US20230220559A1 (en) 2023-07-13

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