Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/50—Multilayers
  • B05D7/51—One specific pretreatment, e.g. phosphatation, chromatation, in combination with one specific coating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/50—Multilayers
  • B05D7/52—Two layers
• • 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
• • 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
  • C23C22/82—After-treatment
  • C23C22/83—Chemical after-treatment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D2701/00—Coatings being able to withstand changes in the shape of the substrate or to withstand welding

Definitions

• the invention relates to a corrosion protection method for use in the production of painted metallic components of organically pre-coated metal sheets.
• a corrosion protection layer provided, which serves as a primer for the subsequent painting.
• Components assembled from metal sheets can be composed of metal sheets which are not yet a permanent corrosion-protective coating exhibit.
• a permanent corrosion-protective Coating consisting of a conversion layer and a coating layer be generated after assembly of the metallic components.
• a well-known Example of this is the process sequence phosphating and painting, as for example is common in the automotive industry.
• the actual phosphating is only one Step in a treatment sequence, which usually in addition to cleaning and rinsing a Activation before phosphating, the actual phosphating and often a Nachpassivitation after phosphating. Thereafter, close several paint stages at.
• Pre-treatment before painting therefore requires several treatment steps, in turn, a correspondingly extensive and therefore costly pretreatment plant make necessary.
• phosphating produces heavy metal-containing Waste that must be disposed of costly.
• conversion layer a layer on a metal surface understood by “conversion treatment” is formed under the action of a “conversion solution” and both Contains elements of the metal surface as well as from the conversion solution.
• conversion solution a complex fluorides of boron, silicon, titanium or Zircon. Most often, these complex fluorides are combined with organic polymers used. Examples of such conversion treatments are described in DE-A-101 31 723 and cited there literature called. However, none of these alternative methods have been available so far replace the phosphating as a pre-treatment before painting in the automotive industry.
• pre-coated metal strips are already offered on the market. On the one hand, these can be pre-phosphated, ie they can carry a phosphate layer but no further coating based on organic polymers. In the automotive and household appliance industry, metal strips are increasingly being processed which are already provided with a corrosion protection layer by the manufacturer of the strips.
• Such materials are known, for example, under the names Granocoat R , Durasteel R , Bonazinc R and Durazinc R. They carry a thin organic coating over a conversion layer, for example a chromating or phosphating layer.
• the organic coating consists of polymer systems such as epoxy or polyurethane resins, polyamides and polyacrylates. Solid additives such as silicic acids, zinc dust and soot improve the corrosion protection and, due to their electrical conductivity, allow the metal parts coated with layers of about 0.3 to about 10 ⁇ m, preferably up to about 5 ⁇ m, to be electrically welded and electrolytically painted.
• the coating of the substrate materials is generally carried out in a two-stage process, in which first the inorganic conversion layer is produced and subsequently the organic polymer film is applied in a second treatment stage. Further information can be found in DE-A-100 22 075 and in the literature cited therein.
• the phosphating could be by a less expensive pretreatment process be replaced when the vehicle bodies made exclusively from organic precoated metal substrate would be made.
• this must be the problem be resolved that in the assembly of bodies from organically pre-coated Metal sheets inevitably arise in places where the organic precoating damaged or missing. This is for example at cut edges, at welding points and at polished places the case.
• metal substrates are the aforementioned sites with damaged organic Layer is particularly difficult to treat because of their electrochemical Differentiate potentials and their chemical reactivity from the usual metal surfaces.
• damaged areas are usually both shares of the steel substrate (ie iron) as well as the zinc coating bare.
• This can be a high local area ratio of steel (iron) to zinc, for example a ratio of> 9: 1 this is the case with cut edges which cross section through the coated one Represent steel substrate.
• the corrosion conditions give way to these border areas, the Zinc and iron combine, from the other conditions on the homogeneous surface from.
• All metal parts of the component should therefore be made of organically pre-coated galvanized Steel exist.
• the component can still components Made of plastic, as it may be the case for example in the automotive industry. to For example, manufacture of a vehicle body so can the metallic components be assembled from organic pre-coated galvanized steel with plastic parts.
• galvanized steel includes hot dip galvanized steels and electrolytic galvanized steels. Furthermore, alloy-galvanized steels are included, in which the coating for example, a zinc-nickel alloy or a zinc-aluminum alloy can exist. The steels may be tempered after galvanizing, so that forms an iron-zinc alloy at the boundary layer between steel and zinc.
• the joining of the sheets to the component in step a) can according to the usual in Known prior art methods, for example by gluing, flanges, Riveting, flanging and / or welding, in particular by arc welding.
• Next to the Cutting and / or punching in sub-step a) performs joining by welding due to the associated damage to the coating based on organic polymers thereto, that more places arise on the component, not from the coating based on organic Polymers are covered. These are also passivated in sub-step c), as well as bare metal areas created by grinding.
• the inventive method is particularly suitable for the production of components with organic pre-coated sheets, which is a coating based on organic polymers having a thickness in the range of 1 to 10 microns, wherein the coating in addition to the organic polymers containing electrically conductive particles. Because of these features the organic coating, the components can be joined together by arc welding become. Examples of such coatings are described in DE-A-197 48 764, DE-A-199 51 113, DE-A-100 22 075 and in the literature cited therein. How introductory mentioned, metal strips with such coatings are under different trade names commercially available.
• the passivation layer produced in sub-step c) should therefore not be a conventional zinc phosphate layer represent, as in accordance with the present task a compared shortened zinc phosphating and thus used more economical process sequence shall be.
• a zinc phosphate layer does not form if the treatment solution does not simultaneously at least 0.3 g / l zinc ions and at least 3 g / l phosphate ions (as phosphoric acid or any protolysis step thereof).
• sub-step c) you can the assembled component in different ways with the contact acidic aqueous treatment solution, for example by immersion in the treatment solution or by spraying with the treatment solution.
• this Step can be rinsed with water, but does not have to. Ie. the process can be called “rinse” or as a “no-rinse” method.
• the treatment according to sub-step c) does not post-passivate a previous one it is the only treatment step after assembling the components, on the bare metal parts generates a passivation layer.
• the aqueous treatment solution in sub-step c) preferably has a pH of at least 2, in particular from at least 2.5, to at most 5, in particular to at most 4.
• a pH of at least 2 in particular from at least 2.5, to at most 5, in particular to at most 4.
• the pickling attack is increasingly too weak, so that only an insufficient Passivation layer forms.
• the transitions are in practice each fluent.
• chromium-free acidic aqueous treatment solutions can be used, which are known in the art for the large-scale treatment of uncoated metal parts or metal strips.
• a treatment solution is used, the total of at least 0.01 g / l, preferably at least 0.025 g / l, and up to 10 g / l, preferably up to 1 g / l, in particular to 0.5 g / l Ti and or Zr and / or Si ions and at least one such amount of fluoride contains that the atomic ratio of Ti to F and / or Zr to F and / or Si to F in the range of 1: 1 to 1: 6, and which additionally contains at least 0.005 g / l, preferably at least 0.01 g / l, and up to 20 g / l, preferably up to 1 g / l of organic polymers.
• the said Ti, Zr and / or Si ions can be used completely in the form of hexafluoro complexes such as, for example, the hexafluoroacids or their salts which are soluble in water in the stated concentration range, for example the sodium salts.
• the atomic ratio is 1: 6.
• complex compounds in which less than six fluoride ions in each case are connected to the central elements Ti, Zr or Si can form themselves in the treatment solution if hexafluoro complexes of at least one of the central elements Ti, Zr or Si and also at least one further compound of one of these central elements are added to it.
• further compounds are, for example, nitrates, carbonates, hydroxides and / or oxides thereof or another of the three mentioned central elements into consideration.
• the treatment solution hexafluorozirconations and (preferably colloidal) silica (SiO 2 ) or their reaction products. Unreacted silica may be suspended in the treatment solution.
• Such a treatment solution can also be obtained by using hydrofluoric acid or its (optionally acidic) salts together with those compounds of Ti, Zr and / or Si which can form fluorocomplexes herewith. Examples are the already mentioned nitrates, carbonates, hydroxides and / or oxides.
• the atomic ratio may also become less than 1 to 6 when the treating solution contains more fluoride, for example in the form of hydrofluoric acid or its salts, than is stoichiometrically required to form the hexafluorocomplexes of the central metals Ti, Zr and / or Si.
• the atomic ratio may become as small as 1 to 12 or 1:18, or even less, by employing a corresponding excess of fluoride, ie, two or three times or even more times what is necessary to complete formation of the hexafluoro complexes.
• treatment solutions in which the organic polymers are selected from homopolymers and copolymers of vinylpyrrolidone.
• Such treatment solutions are described in DE-A-100 05 113 and DE-A-101 31 723.
• Suitable homopolymers or copolymers of vinylpyrrolidone are, for example, the polymers or polymers listed in Table 1 of the monomers mentioned there. Copolymers of vinylpyrrolidone with monomers having caprolactam or imidazole groups are particularly preferred.
• the preferred treatment solutions described above are preferred a temperature in the range of 20 to 45 ° C, in particular from 30 to 40 ° C. This treatment solution preferably for a period of time in the range of 1 to 5 minutes, in particular from 2 to 3 minutes with the cleaned joined component in Contact.
• the treatment solutions to be used should be free of chromium.
• the acidic aqueous treatment solution except metals of the 4. subgroup of the periodic table (for example in the form of complex fluorides of Ti and / or Zr) contains no other subgroup metals ("transition metals"). hereby the treatment of wastewater is simplified.
• the metallic component pretreated in sub-step c) can be used with or without Intermediate rinse as sub-step d) - with a customary for the intended use Varnish to be coated.
• this may be selected from a dip paint, an electrodeposition paint or a powder paint.
• the present invention relates to a painted, galvanized metal parts Steel-containing component obtainable by the method described above is.
• this is understood to mean that all metal parts of the component Made of organically pre-coated galvanized steel.
• the component may still contain plastic components, such as for example in the automotive industry may be the case.
• the inventive method can be painted metallic components such as Vehicle bodies, household appliances, furniture or parts thereof, the current demands on appearance, corrosion resistance and paint adhesion fulfill.
• organically pre-coated raw material Can the manufacturer of the components significantly reduces the required chemical treatment become. This brings economic and ecological advantages for the manufacturer of the components With it, since a less expensive pretreatment plant is sufficient and less polluted wastewater.
• Example 1 Conversion treatment of molded parts (Material: Electrolytic galvanized with Granocoat® ZE coating)
• Comparative Example 1 Zinc phosphating of molded parts (material: electrolytically galvanized with Granocoat® ZE coating )
• Example 2 Conversion treatment of molded parts (material: electrolytically galvanized with Granocoat® S coating)
• Example 3 Conversion treatment of molded parts (Material: Hot dip galvanized Steel with Granocoat® ZE coating)
• test results show that with the shorter process sequence according to the invention at least the same results as with zinc phosphating.
• the trend the results according to the method according to the invention are even better than those obtained by zinc phosphating.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Wood Science & Technology (AREA)
• Materials Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Chemical Treatment Of Metals (AREA)
• Laminated Bodies (AREA)

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• 2003
  • 2003-11-14 DE DE10353149A patent/DE10353149A1/de not_active Withdrawn
• 2004
  • 2004-09-23 AT AT04022644T patent/ATE516088T1/de active
  • 2004-09-23 EP EP04022644A patent/EP1531012B1/fr not_active Not-in-force
  • 2004-11-12 US US10/987,998 patent/US20050121113A1/en not_active Abandoned

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