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
  • B05D7/50—Multilayers
  • B05D7/52—Two layers
  • B05D7/54—No clear coat specified
  • B05D7/546—No clear coat specified each layer being cured, at least partially, separately
• • 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
• • 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
  • C23C22/48—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 not containing phosphates, hexavalent chromium compounds, fluorides or complex fluorides, molybdates, tungstates, vanadates or oxalates
  • C23C22/56—Treatment of aluminium or alloys based thereon
• • 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
  • B05D2202/00—Metallic substrate
  • B05D2202/20—Metallic substrate based on light metals
  • B05D2202/25—Metallic substrate based on light metals based on Al
• • 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
  • B05D2701/10—Coatings being able to withstand changes in the shape of the substrate or to withstand welding withstanding draw and redraw process, punching
• • 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
  • C23C2222/00—Aspects relating to chemical surface treatment of metallic material by reaction of the surface with a reactive medium
  • C23C2222/20—Use of solutions containing silanes

Definitions

• the invention relates to a method for producing weather and corrosion resistant Formed sheet metal parts made of aluminum or an aluminum alloy with a decorative surface.
• the parts are first made from a conventional process Band punched out and formed. Pretreatment and application Further surface layers are carried out on the parts that have already been formed. This procedure is very complex and complex Handling connected because the sheet metal parts to be treated in different baths put on holder and often from one holder to another have to be repositioned.
• the invention has for its object a method of the aforementioned To create kind that under the continuous production of formed parts Allows application of a coil coating process.
• the sol-gel varnish is preferably an alcoholic silane solution, preferably an alkoxysilane solution, and an aqueous colloidal silica solution manufactured polysiloxane and consists in particular of cross-linked inorganic polysiloxanes with over carbon bonds with the Silicon-linked organic groups, especially alkyl groups.
• polysiloxane is the term for polymers made from cross-linked siloxanes.
• Aluminum with a purity of 98.3% and higher can be used depending on the requirements placed on the surface quality e.g. Aluminum with a purity of 99.0% and higher, sometimes also with a purity of 99.5%. In particularly stored cases, a purity of 99.8% and be displayed higher.
• the purities mentioned can also Aluminum alloys are used. Preferred alloys are those of the series AA 1000, AA 3000 and AA 5000.
• Alloys contain, for example, 0.25 to 5% by weight, in particular 0.5 to 4% by weight magnesium or 0.2 to 2% by weight manganese, or 0.5 to 5% by weight Magnesium and 0.2 to 2 wt .-% manganese, in particular 1 wt .-% magnesium and 0.5% by weight of manganese, or 0.1 to 12% by weight, preferably 0.1 to 5 %
• copper or 0.5 to 6% by weight zinc and 0.5 to 5% by weight magnesium, or 0.5 to 6% by weight zinc, 0.5 to 5% by weight magnesium and 0.5 to 5% by weight Copper, 0.5 to 2% by weight iron and 0.2 to 2% by weight manganese, in particular 1.5% by weight iron and 0.4% by weight manganese, or AIMgSi or AIFeSi alloys.
• Other examples are AIMgCu alloys such as AlMg0.8Cu or AIMg alloys such as AIMg1, or AIFeMn alloys such as AlFeMn1.5.
• the sheet metal parts can for example be bent, deep drawn or cold extruded or roll forming, but also be formed using other forming processes.
• the pretreatment layer can be made, for example, by chromating, Phosphating or layer produced by anodic oxidation.
• the pre-treatment layer made of anodized aluminum.
• the pretreatment layer can have a thickness of, for example, at least 10 nm, preferably of at least 20 nm, in particular of at least 50 nm and advantageously have at least 100 nm.
• the maximum thickness of the pretreatment layer is, for example, 5000 nm, preferably 1500 nm and especially 300 nm.
• the pretreatment layer is preferably an anodically produced oxide layer, built up in a non-redissolving or in a redissolving electrolyte has been.
• the pretreatment layer is preferably a porous, anodic generated oxide layer.
• the anodization preferably takes place in an acidic electrolyte from the Series of phosphoric, citric, tartaric, chromic acid electrolytes and especially from the series of sulfuric acid electrolytes.
• the anodization takes place in the AC or DC method.
• the pretreatment layer can also be a yellow chromating layer, a green chromating layer, a phosphate layer or a chrome-free pretreatment layer, those contained in at least one of the elements Ti, Zr, F, Mo or Mn Electrolyte has been formed included.
• the aluminum surface can be pretreated in a chemical or electrochemical processes or an alkaline pickling process be subjected. Such glossy or pickling processes are before nodize performed.
• the belt surface is expediently degreased and cleaned.
• the pretreatment can only be degreased and cleaned of the belt surface.
• the belt surface can be cleaned on known way, e.g. chemical and / or electrochemical and acidic or alkaline. Its purpose is to remove foreign substances and, if necessary the naturally created oxide layer on the aluminum surface.
• Suitable cleaning agents are e.g. acidic, aqueous degreasing agents, alkaline Degreasing agent based on polyphosphate and borate.
• a cleaning with moderate to heavy material removal forms pickling or etching by means of strongly alkaline or acidic pickling solutions, e.g. Caustic soda or a mixture of nitric acid and hydrofluoric acid.
• the existing one Removed oxide layer and its impurities. With strongly attacking alkaline Pickling may require acidic after-treatment.
• the aluminum strip runs through the various treatment baths continuously at a speed of, for example, 40 m / min.
• the protective layer and if necessary, additional layers are applied.
• the sol-gel lacquer applied to the pretreatment layer is preferably a from an alcoholic silane solution, in particular an alkoxysilane solution, and a colonial silica solution polysiloxane.
• the polysiloxane is particularly hydrolyzed by a condensation reaction between and crosslinkable silanes, especially alkoxysilanes, and colloidal Silica produces.
• the condensation reaction between hydrolyzed silanes, especially alkoxysilanes, with each other as well as hydrolyzed silanes, especially alkoxysilanes, and colloidal silica leads to the formation of an inorganic Network of polysiloxanes.
• organic groups in particular Alkyl groups or simple alkyl groups via carbon bonds built into the inorganic network.
• the organic groups or the alkyl groups do not take part directly in the polymerization or the Cross-linking of the siloxanes, i.e. they are not used to form an organic Polymer system but only for functionalization.
• the function is that the organic groups, especially the alkyl groups, attached to the outside of the polysiloxanes during the sol-gel process and thereby form a layer that is water-repellent to the outside, which gives the sol-gel varnish a pronounced hydrophobic property gives.
• sol-gel process described leads, as mentioned, by targeted hydrolysis and condensation of alkoxides of silicon and silica to form a sol-gel lacquer from an inorganic network with built-in alkyl groups.
• the polysiloxanes thus obtained are therefore rather inorganic Classify polymers.
• sol-gel lacquer as Protective layer is expediently based on two basic solutions A and B.
• Solution A is an alcoholic solution of one or more different ones Alkoxysilanes, the alkoxysilanes not in an anhydrous medium hydrolyzed form.
• An alcohol is expediently used as solvent, such as, for example, methyl, ethyl, propyl or butyl alcohol and preferably isopropyl alcohol, used.
• alkoxysilanes are described by the general formula X n Si (OR) 4-n , in which "R” is simple alkyl, preferably from the group comprising methyl, ethyl, propyl and butyl. "X” is also expediently an alkyl, preferably from the group comprising methyl, ethyl, propyl and butyl.
• Suitable alkoxysilanes are, for example, tetramethoxysilanes (TMOS) and preferably tetraethoxysilane (TEOS) and methyltrimethoxysilane (MTMOS) and other alkoxysilanes.
• solution A is made from tetraethoxysilane (TEOS) and / or methyltrimethoxysilane (MTMOS) with a methyl, Ethyl or propyl alcohol and especially with an isopropyl alcohol as Prepared solvent.
• TEOS tetraethoxysilane
• MTMOS methyltrimethoxysilane
• Solution A can e.g. 25-35% by weight, in particular 30% by weight, TEOS and 15-25% by weight, in particular 20% by weight, Contain MTMOS, both dissolved in 40-60% by weight, in particular 50% by weight, Isopropyl alcohol.
• Solution B contains colloidal silica dissolved in water.
• solution B is adjusted to a pH between 2.0-4, preferably between 2.5-3.0 and in particular 2.7, using acid, preferably nitric acid (HNO 3 ).
• the silica used is expediently a silica stabilized in an acidic environment, the pH of the silica advantageously being 2-4.
• the silica is advantageously low in alkali.
• the alkali content (eg Na 2 O) of the silica is preferably below 0.04% by weight.
• Solution B contains, for example, 70-80% by weight, in particular 75% by weight, water as solvent and 20-30% by weight, in particular 25% by weight, of colloidal silica.
• Solution B is expediently adjusted to a pH between 2.0-3.5, preferably between 2.5-3.0, and in particular 2.7, using nitric acid (HNO 3 ).
• HNO 3 nitric acid
• a preferred silica solution is, for example, by the company Nissan Chemical Industries Ltd. with the product name "SNOWTEX® O".
• the sol-gel lacquer is expediently applied in gel form to the surface of the Aluminum tape applied and then dried or hardened.
• the continuous coating is done in the coil painting process, too Coil coating process called.
• a typical coil coating process is a Roller application process with two or three rollers.
• the layer thickness of the cured Sol-gel lacquer is preferably at least 1 ⁇ m and is preferably between 1 and 4.5 ⁇ m, in particular between 1 and 3 ⁇ m. contains If the sol-gel lacquer also contains color pigments, the layer thickness can be up to 10 ⁇ m.
• the drying process consists of the water remaining in the sol-gel varnish and drive out alcohols, whereby the sol-gel varnish hardens and a weather-resistant and corrosion-resistant protective layer on the belt surface arises.
• the tape coated with the sol-gel varnish is expediently used Radiation, such as UV radiation, electron radiation, laser radiation, or by means of Heat radiation, such as IR radiation, or by means of convection heating or a combination of the aforementioned drying or curing processes, dried respectively. hardened.
• Radiation such as UV radiation, electron radiation, laser radiation, or by means of Heat radiation, such as IR radiation, or by means of convection heating or a combination of the aforementioned drying or curing processes, dried respectively. hardened.
• the temperature measured on the belt surface for drying or hardening the sol-gel lacquer is expediently greater than 60 ° C., preferably greater than 150 ° C and especially greater than 200 ° C.
• the elevated temperature is furthermore expediently less than 400 ° C., preferably less than 350 ° C. and in particular less than 300 °.
• the temperature is particularly preferred between 250 ° C and 300 ° C.
• the temperature specification is a so-called "Peak Metal Temperature” (PMT).
• the elevated temperature can, for example, last for 5 seconds to 2 minutes act on the tape.
• the sol-gel varnish is preferred for a period of time less than 90 seconds, especially less than 60 seconds, and preferably more than 10 seconds, especially more than Dried or hardened for 30 seconds.
• the Drying times tend to be in the lower range of the specified stay times.
• Convection heating can be carried out expediently by applying heated gases such as air, nitrogen, noble gases or mixtures thereof.
• heated gases such as air, nitrogen, noble gases or mixtures thereof.
• the sol-gel lacquer layer is dried in a continuous oven.
• the formed parts are after the application and drying of the protective layer punched out of the band and formed.
• the forming hardly leads to crack formation in the protective layer.
• the formed parts produced by the process according to the invention have thanks to the hard protective layer with excellent adhesion good protection against weather, corrosion and mechanical Abrasion and are characterized by good UV resistance out.
• the molded parts produced according to the invention have a sol-gel protective layer made of polysiloxanes with a high surface hardness.
• the sol-gel protective layer expediently has a pencil method according to Wolf Wilburn "according to DIN 55350 part 18 hardness of greater than "f ', preferably greater than” h ", in particular greater than” 2h “and advantageous from larger "3h", whereby larger in the sense of harder to understand is.
• the sol-gel layer is also characterized by excellent adhesion on the formed sheet metal parts.
• the pH of solution B is adjusted to approximately 2.7 with the addition of an acid, in particular nitric acid (HNO 3 ).
• sol-gel varnish and the coating of the aluminum strip is carried out in a preferred embodiment as follows:
• the solutions A and B are under continuous Stirring transferred into a mixed solution, heat due to reaction is released.
• the mixed solution is over a certain time, for example for 1 h to 10 h, preferably during 4 to 8 h, in particular stirred for around 6 h.
• the mixture is then filtered.
• the filter serves to hold back larger Particles such as Particles of colonial silica.
• the pore diameter or the mesh size of the filter depends on the desired layer thickness, because particles with a larger diameter than the desired layer thickness affect the surface quality of the protective layer. Filtration can for example using a polypropylene filter with a porosity of 1 ⁇ m.
• the mixed solution is expediently at a pH of 2-4, preferably from 2 to 3.5, in particular from 2.5 to 3, and particularly preferably from 2.7, held.
• the pH is adjusted using acid, preferably using Nitric acid.
• the sol-gel varnish can be removed using one of the the aforementioned method is applied to the belt surface and subsequently, can be dried or hardened as described above.
• the sol-gel varnish after its manufacture and before application to the belt surface during a few minutes to several hours, preferably between 1 and 24 hours, especially between 12 and 22 h and particularly preferably for around 17 h immobilized.
• the element analysis of the hardened sol-gel varnish using XPS has e.g. the elements oxygen, silicon and around 5 - 20 at.% (atomic percent) carbon after.

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Cited By (8)

Citations (4)

• 2003
  • 2003-03-12 EP EP03405173A patent/EP1457267A1/fr not_active Withdrawn
• 2004
  • 2004-03-09 ES ES04405138T patent/ES2252727T3/es not_active Expired - Lifetime
  • 2004-03-09 DE DE502004000159T patent/DE502004000159D1/de not_active Expired - Lifetime

Patent Citations (4)

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