Classifications

• • 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
  • C25D13/12—Electrophoretic coating characterised by the process characterised by the article coated
  • C25D13/16—Wires; Strips; Foils
• • 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
  • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/24—Electrically-conducting paints
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/44—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications
  • C09D5/4419—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications with polymers obtained otherwise than by polymerisation reactions only involving carbon-to-carbon unsaturated bonds
  • C09D5/443—Polyepoxides
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/44—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications
  • C09D5/4419—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications with polymers obtained otherwise than by polymerisation reactions only involving carbon-to-carbon unsaturated bonds
  • C09D5/4461—Polyamides; Polyimides
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/44—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications
  • C09D5/4419—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications with polymers obtained otherwise than by polymerisation reactions only involving carbon-to-carbon unsaturated bonds
  • C09D5/4465—Polyurethanes
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/44—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications
  • C09D5/448—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications characterised by the additives used
• • 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
  • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
  • C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
  • C23C2/06—Zinc or cadmium or alloys based thereon
• • 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
  • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
  • C23C2/26—After-treatment
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D15/00—Electrolytic or electrophoretic production of coatings containing embedded materials, e.g. particles, whiskers, wires
  • C25D15/02—Combined electrolytic and electrophoretic processes with charged materials
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/22—Electroplating: Baths therefor from solutions of zinc
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/60—Electroplating characterised by the structure or texture of the layers
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/10—Electroplating with more than one layer of the same or of different metals
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/48—After-treatment of electroplated surfaces
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
  • Y10T428/12556—Organic component
  • Y10T428/12562—Elastomer
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
  • Y10T428/12556—Organic component
  • Y10T428/12569—Synthetic resin
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12771—Transition metal-base component
  • Y10T428/12785—Group IIB metal-base component
  • Y10T428/12792—Zn-base component

Definitions

• the present invention relates to a sheet of bare steel or galvanized steel coated with a layer of zinc or zinc alloy comprising a polymer, as well as a method of manufacturing such a sheet by electrodeposition. These sheets are more particularly intended for the manufacture of automobiles.
• the invention therefore aims to remedy the drawbacks of the prior art by providing a coated sheet allowing direct subsequent adhesion of organic coatings in thin layer, without harm to the environment, with improved productivity.
• a first object of the invention is constituted by a sheet of bare steel or galvanized steel, characterized in that it is further coated on at least one of its faces by a single layer of zinc or zinc alloy containing 0.15 to 1% by weight of a polymer consisting of 6 to 150 identical or different units, preferably at most 80 identical or different units, and advantageously 20 to 30 identical or different units, of general formula:
• the sheet according to the invention successively comprises:
• the sheet can also further comprise a layer of zinc interposed between the steel layer and the single layer of zinc or zinc alloy containing the polymer.
• the sheet according to the invention successively comprises:
• a layer based on polyurethane optionally comprising electroconductive particles, such as, for example, zinc particles and / or iron phosphides.
• it can also further comprise a layer of zinc interposed between the steel layer and the single layer of zinc or zinc alloy containing the polymer.
• the sheet according to the invention as it has just been defined in its various embodiments can, in addition, be such that the single layer of zinc or zinc alloy containing the polymer is in turn covered with an organic coating layer, chosen from the group formed by polyurethanes, epoxy resins, polyesters, and their mixtures, said organic coating possibly also comprising electrically conductive particles.
• the polymer content of its coating layer is between 0.15 and 1% by weight, preferably between 0.15 and 0.60% by weight.
• the method according to the invention can also have the following characteristics, alone or in combination:
• the polymer concentration in the bath is between 0.9 and 1.1 g / l
• the sheet of bare steel or zinc-plated steel is passed through the electrodeposition bath at a speed of between 50 and 150 m / min, - the Zn ++ ion concentration of the electrodeposition bath is between 40 and 100 g / l,
• the temperature of the electrodeposition bath is between 30 and 70 ° C
• the average current density is less than 120 A / dm 2 .
• the invention consists in depositing a zinc coating on a bare or galvanized steel sheet, said zinc coating incorporating a particular organic molecule, on the surface and / or in the mass of the zinc coating.
• the sheet thus coated has excellent adhesion characteristics for a subsequent organic coating, without the need to carry out a pretreatment toxic to the environment.
• the composite coating (zinc / organic polymer) can be deposited by any suitable process.
• the organic molecule can be added to an electrodeposition bath before the actual electrodeposition operation.
• the coating is then deposited under the conventional conditions of electrodeposition of a metal coating.
• the organic molecule present in the bath is incorporated into the mass and / or on the surface of the metal coating, which leads to the production of a composite coating (zinc + organic molecule).
• the inventors have shown that when the polymer concentration in the electroplating bath is insufficient, that is to say less than 0.8 g / l, the incorporation of the polymer into the composite coating is insufficient.
• the surface appearance of the composite coating (zinc / polymer) is degraded.
• the polymer concentration in the bath is preferably included between 0.9 and 1.1 g / l.
• the coating can be deposited on one side, or on both sides of the steel sheet.
• the electrodeposition bath that can be used to implement the method according to the invention is based on sulfates and comprises, in particular, zinc sulfate, and at least one support salt, as well as the organic molecule according to the invention.
• the current density must remain less than 160 A / dm 2 , since from 160 A / dm 2 the burn-out limits of the coating are reached composite (zinc / polymer), which results in a dark and dendritic appearance of the coating. It is preferably less than 120 A / dm 2 , because the inventors have demonstrated that from this value, the adhesion of the organic coating begins to deteriorate, and to avoid this degradation, it is also necessary to simultaneously increase the speed of the steel sheet in the electroplating bath.
• the running speed of the steel sheet is greater than 150 m / min, the deposition of the composite coating (zinc / polymer) becomes insufficient for the adhesion of the subsequent organic coating to be sufficient. If the running speed is less than 50 m / min, the adhesion of the organic coating is insufficient, because the threshold current density from which the burns of the composite coating begin to occur is reduced.
• the concentration of Zn 2+ ion in the electrodeposition bath must be less than 100 g / l, since the inventors have demonstrated that beyond 100 g / l the adhesion of the organic coating is insufficient. It must be greater than 40 g / l to avoid the burn problems of the composite coating.
• the bath temperature is between 30 and 70 ° C, in fact it is not conceivable, in industry, to work at temperatures above 70 ° C when it is not necessary. In addition, below 30 ° C, the conductivity of the bath becomes insufficient for the deposition of the composite coating on the sheet to be done correctly.
• a bilayer coating (zinc) / (zinc + organic molecule), still by electrodeposition.
• the bath of pure zinc is then used on the first cells of the line in order to deposit a first layer of zinc, while the bath enriched in organic molecule is used on the cells at the end of the line in order to deposit a second layer of zinc. organic molecule.
• the present inventors believe that the organic functions present on the surface of the zinc coating could be used as a base for attaching the organic coating, thus ensuring its adhesion to the metallic coating in the absence of any treatment. surface area.
• the molecules used in the context of the present invention are polymers consisting of 6 to 150 identical or different units, preferably at most 80 identical or different units, and advantageously from 20 to 30 identical or different units, of general formula:
• polymers such as polyacrylamides or polymethacrylamides, but also polyacrylamide / polyallyl copolymers.
• Example 1 An electroplating bath having the following composition is prepared:
• M4 polyacrylamide of which the group R is H, of molecular mass 1500 g, comprising about 25 patterns).
• the pH of the bath is close to 0 and its bath temperature is maintained between 40 and 60 ° C.
• a steel plate is placed on a cathode.
• the cathode is placed facing an insoluble anode.
• the support salt previously prepared, is circulated in the interval between the cathode and the anode at speeds approaching 100 m / min (the width of the interval between the cathode and the anode is 10 mm).
• An electric current of about 100 A / dm 2 is then passed until a coating with a thickness of 7.5 ⁇ m is obtained.
• the Zn-4 composite deposit thus obtained has a perfectly homogeneous appearance.
• the layer has a thickness of between 6 and 8 ⁇ m.
• the sheet A thus coated is in accordance with the invention.
• Granodin 1456 is applied using a coating tool of the roll-coat type and with a deposited layer weight included in the range recommended by the supplier (ie 8-12 mg / m 2 of deposited titanium).
• a steel sheet is made coated with a layer of Zn / lv.4 obtained under the same conditions as those described in the test carried out in Example 1.
• a layer based on epoxy resin containing zinc micro-balls, of the Bonazinc 3005 type (sold by PPG) is applied to the surface coated with Zn-M4. ).
• the layer has a thickness of between 5 and 6 ⁇ m.
• the sheet D thus coated is in accordance with the invention.
• the coatings of pure zinc were developed under the conditions of the prior art (without M4 in the bath). Nupal is applied using a tool coating of the roll-coat type and with a deposited layer weight included in the range recommended by the supplier (ie 80-120 mg / m 2 of dry extract).
• ZnSO 4 , 7H 2 O concentrations of ZnSO 4 , 7H 2 O
• the Zn 2+ concentrations are respectively 85 g / l and 119 g / l.
• a polyacrylamide with a molecular weight of 10,000 g comprises approximately 166 units.
• a steel plate is deposited on a cathode.
• the cathode is placed facing an insoluble anode.
• the support salt previously prepared, is circulated in the interval between the cathode and the anode at speed V (the width of the interval between the cathode and the anode is 10 mm).
• An electric current is then passed with a DC current density until a coating of 7.5 ⁇ m in thickness is obtained.
• the zinc-polyacrylamide deposit thus obtained has a perfectly homogeneous appearance.
• the values of the parameters outside the invention have been underlined.
• a layer comprising a resin based on epoxy and polyurethane containing zinc beads, of the Granocoat ZE type is applied to the surface coated with Zn-polyacrylamide. (marketed by Henkel).
• Zn-polyacrylamide marketed by Henkel
• two coated steel sheets are also prepared according to the prior art: a steel sheet V covered with a layer of 7.5 ⁇ m of pure zinc, then directly one with a layer of Granocoat ZE , - a steel sheet W covered with a layer of 7.5 ⁇ m of pure zinc, then a conversion treatment obtained from a Granodine 1457 solution marketed by Henkel (based on titanium), then d '' a layer of Granocoat ZE with a thickness of 4 ⁇ m.
• Granodine 1457 is applied using a roll-coat type tool and with a deposited layer weight included in the range recommended by the supplier (ie 8 mg / m 2 of titanium).
• the polyacrylamide concentration is between 0.8 and 1.2 g / l, and preferably between 0.9 and 1.1 g / l. Indeed, when the polyacrylamide concentration is 0.2 or 0.5 g / l (sheets G and H), this is insufficient to obtain good adhesion of the organic coating.
• the number of units included in the polyacrylamide does not exceed 150.
• a polyacrylamide of general formula is used in accordance with the invention but comprising approximately 166 units (sheet U)
• the adhesion of the organic coating is insufficient.
• the concentration of PAC of molecular weight of 10,000 g has been greatly reduced, since the inventors have found that when its concentration is 1 g / l, then the surface appearance of the composite coating is greatly degraded, which is unacceptable.
• either the surface appearance of the coating is disadvantaged by maintaining the concentration of the polymer in the electrolytic bath at approximately 1 g / l in accordance with the invention, or an insufficient adhesion of the organic coating is obtained by reducing the concentration of the polymer in the electrolytic bath.
• the current density is between 120 and 160 A / dm 2
• the speed is adjusted by increasing it, so as to avoid the burning phenomena of the composite coating (zinc + polymer).
• care must also be taken to reduce the current density to avoid the burning phenomena of the composite coating.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Metallurgy (AREA)
• Life Sciences & Earth Sciences (AREA)
• Electrochemistry (AREA)
• Wood Science & Technology (AREA)
• Mechanical Engineering (AREA)
• Health & Medical Sciences (AREA)
• Molecular Biology (AREA)
• Electroplating Methods And Accessories (AREA)
• Laminated Bodies (AREA)
• Electroplating And Plating Baths Therefor (AREA)

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• 2002
  • 2002-11-19 FR FR0214421A patent/FR2847275B1/fr not_active Expired - Fee Related
• 2003
  • 2003-11-14 CN CNA2003801036674A patent/CN1714176A/zh active Pending
  • 2003-11-14 BR BR0316302-4A patent/BR0316302A/pt not_active Application Discontinuation
  • 2003-11-14 WO PCT/FR2003/003377 patent/WO2004048645A1/fr not_active Application Discontinuation
  • 2003-11-14 JP JP2004554600A patent/JP2006506531A/ja active Pending
  • 2003-11-14 KR KR1020057009093A patent/KR20050075441A/ko not_active Application Discontinuation
  • 2003-11-14 US US10/532,804 patent/US20060166031A1/en not_active Abandoned
  • 2003-11-14 CA CA002506355A patent/CA2506355A1/fr not_active Abandoned
  • 2003-11-14 MX MXPA05005285A patent/MXPA05005285A/es unknown
  • 2003-11-14 AU AU2003290200A patent/AU2003290200A1/en not_active Abandoned
  • 2003-11-14 EP EP03782562A patent/EP1565597A1/fr not_active Withdrawn
  • 2003-11-14 RU RU2005119188/02A patent/RU2005119188A/ru not_active Application Discontinuation

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