EP0273408A2 - Process for producing coatings on metal surfaces - Google Patents
Process for producing coatings on metal surfaces Download PDFInfo
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- EP0273408A2 EP0273408A2 EP87119190A EP87119190A EP0273408A2 EP 0273408 A2 EP0273408 A2 EP 0273408A2 EP 87119190 A EP87119190 A EP 87119190A EP 87119190 A EP87119190 A EP 87119190A EP 0273408 A2 EP0273408 A2 EP 0273408A2
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- water
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- 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
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- 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
- C23C22/24—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 hexavalent chromium compounds
- C23C22/26—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 hexavalent chromium compounds containing also organic compounds
- C23C22/28—Macromolecular compounds
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- 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
- C23C22/73—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 characterised by the process
- C23C22/74—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 characterised by the process for obtaining burned-in conversion coatings
Definitions
- the present invention relates to a process for the production of corrosion-protective coatings on surfaces of metals other than aluminum by drying and heating a water-based coating agent which contains chromium VI and water-soluble or water-dispersible layer-forming organic polymer, and its application to the treatment of galvanized steel surfaces.
- wash primer the main components of which are polyvinyl butyral, hexavalent chromium and phosphoric acid
- the wash primer is flammable because it uses solvents such as e.g. Contains alcohols, and therefore tries to address fire hazard problems.
- solvents such as e.g. Contains alcohols, and therefore tries to address fire hazard problems.
- water-based coating agents have been developed which do not have this disadvantage.
- Japanese Patent Application No. Sho 57-45834 (1982) describes a method in which a treatment solution of water-soluble dichromate or chromic acid and water-soluble resin is applied to the steel sheet and then dried at 40 to 80 ° C. This process focuses on the solubilization of epoxy resin to produce a stable treatment solution.
- Japanese Patent Application Laid-Open No. Sho 60-228682 describes an aqueous solution of chromic acid, water-soluble acrylic resin and complex fluoride salt for the treatment of galvanized steel sheet.
- complex fluoride e.g. Sodium hexafluoroaluminate
- the layer formed should be improved both in terms of corrosion resistance and film adhesion.
- hexavalent chromium content decreases to some extent as a result of reaction with the resin, they suffer from the considerable disadvantage that a large part of hexavalent chromium is not reduced.
- hexavalent chromium can subsequently be removed from the layer, so that the usability of the correspondingly coated sheet is limited.
- the object of the invention is to provide a process for producing corrosion-protective coatings on surfaces of metals other than aluminum, which does not have the aforementioned disadvantage and leads to coatings from which practically no hexavalent chromium can be removed even in the case of long-term contact with aqueous solutions.
- the layer-forming organic polymer to be used in the present invention must be water-soluble or water-dispersible and must be capable of being cured by heating / drying. Suitable examples of such polymers are described in JP-B-58-47230 (1983) (CA 87, No. 2,7657z). Polymers based on acrylic acid or acrylate or of methacrylic acid or methacrylate or copolymers thereof are of particular importance.
- the hexavalent chromium can e.g. be introduced as anhydrous chromic acid or ammonium bichromate.
- anhydrous chromic acid or ammonium bichromate e.g. be introduced as anhydrous chromic acid or ammonium bichromate.
- the addition of smaller amounts of trivalent chromium can be advantageous.
- a preferred development of the invention consists in drying and heating a coating agent that contains the water-soluble organic compound in an amount of 0.1 to 20 g / l, preferably 0.5 to 10 g / l.
- the molar ratio of organic compound to hexavalent chromium is approximately 0.1 to 3, preferably 0.33 to 1.5.
- Another expedient embodiment of the invention provides for the coating agent applied to the metal surface to be heated at a temperature in the range from 100 to 300 °.
- the mode of action of the water-soluble organic compound to be added is not clear. This compound is presumably reduced by the hexavalent chromium in the coating agent layer to trivalent chromium, the solubility of which is lower than that of hexavalent chromium.
- the trivalent chromium in turn reacts with the oxidation product of the added water-soluble compound or the water-soluble or water-dispersible organic polymer and forms a complex compound which practically no longer releases chromium.
- Due to the weak reduction effect at room temperature the formulated coating agent can be stored stably at room temperature. The full The effect of the reduction of the hexavalent chromium only occurs during the heating / drying of the coated metal surface.
- the stability of the coating agent at room temperature can be further improved if the pH value is kept at a slightly higher value by using ammonium bichromate.
- the method according to the invention is suitable for treating a large number of metal surfaces, with the exception of surfaces made of aluminum, such as iron, steel or zinc.
- the method can be used with particular advantage for the production of corrosion-protective coatings on galvanized steel.
- Electrolytically galvanized steel sheet was degreased with an aqueous solution containing sodium phosphate and sodium silicate as the main components. After rinsing the water with an aqueous coating agent, coated that 30 g / l water-soluble acrylate resin (calc. as dry substance), 3.2 g / l Cr6+ and 1.0 g / r Cr3 be harshet contained. After drying for one minute at 180 ° C., the sheet was coated with a coating of 0.2 g / m2.
- Aqueous coating compositions of the composition as in Comparative Example 1 were added with 1.5 g / l ethylene glycol or 3 g / l diethylene glycol or 2 g / l propylene glycol.
- the test panels were treated in the same manner as in the comparative example.
- test specimens of 1 cm2 were cut out, which were immersed in 100 ml of demineralized water at 30 ° C. for seven days. The test specimens were then rinsed with demineralized water. Solution and rinse water were combined and concentrated to 50 ml. The chromium concentration was measured on the principle of atomic absorption spectrometry.
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Abstract
Description
Die vorliegende Erfindung betrifft ein Verfahren zur Erzeugung von korrosionsschützenden Überzügen auf Oberflächen von von Aluminium verschiedenen Metallen durch Auftrocknen und Erhitzen eines Überzugsmittels auf Wasserbasis, daß Chrom VI sowie wasserlösliches oder wasserdispergierbares schichtbildendes organisches Polymer enthält sowie dessen Anwendung auf die Behandlung von verzinkten Stahloberflächen.The present invention relates to a process for the production of corrosion-protective coatings on surfaces of metals other than aluminum by drying and heating a water-based coating agent which contains chromium VI and water-soluble or water-dispersible layer-forming organic polymer, and its application to the treatment of galvanized steel surfaces.
Das vorgenannte Verfahren hat in der Industrie insbesondere bei der Oberflächenbehandlung von Stahlblech oder verzinktem Stahlblech einen weiten Anwendungsbereich gefunden. Auf diesem Sektor ist u.a. der sog. Wash-Primer, dessen Hauptbestandteile Polyvinylbutyral, sechswertiges Chrom und Phosphorsäure sind, als korrosionsverhütendes Überzugsmittel bekannt. Der Wash-Primer ist jedoch entzündlich, da er Lösungsmittel, wie z.B. Alkohole enthält, und versucht daher Probleme bezüglich einer Brandgefahr. Infolgedessen wurden wasserhaltige Überzugsmittel entwickelt, die diesen Nachteil nicht besitzen.The aforementioned method has found a wide range of applications in industry, in particular in the surface treatment of steel sheet or galvanized steel sheet. In this sector, the so-called wash primer, the main components of which are polyvinyl butyral, hexavalent chromium and phosphoric acid, is known as a corrosion-preventing coating agent. However, the wash primer is flammable because it uses solvents such as e.g. Contains alcohols, and therefore tries to address fire hazard problems. As a result, water-based coating agents have been developed which do not have this disadvantage.
So beschriebt die japanische Patentanmeldung Nr. Sho 57-45834 (1982) ein Verfahren, bei dem eine Behandlungslösung aus wasserlöslichem Dichromat oder Chromsäure und wasserlöslichem Harz auf das Stahlblech aufgebracht und dann bei 40 bis 80°C getrocknet wird. Bei diesem Verfahren steht die Solubilisierung von Epoxyharz zur Erzeugung einer stabilen Behandlungslösung im Vordergrund.For example, Japanese Patent Application No. Sho 57-45834 (1982) describes a method in which a treatment solution of water-soluble dichromate or chromic acid and water-soluble resin is applied to the steel sheet and then dried at 40 to 80 ° C. This process focuses on the solubilization of epoxy resin to produce a stable treatment solution.
Die offengelegte japanische Patentanmeldung Nr. Sho 60-228682 (9185) beschreibt eine wässrige Lösung aus Chromsäure, wasserlöslichem Acrylharz und komplexem Fluoridsalz für die Behandlung von verzinktem Stahlblech. Durch den Zusatz von komplexem Fluorid, wie z.B. Natriumhexafluoroaluminat, soll die gebildete Schicht sowohl hinsichtlich Korrosionsbeständigkeit als auch Filmhaftung verbessert werden.Japanese Patent Application Laid-Open No. Sho 60-228682 (9185) describes an aqueous solution of chromic acid, water-soluble acrylic resin and complex fluoride salt for the treatment of galvanized steel sheet. By adding complex fluoride, e.g. Sodium hexafluoroaluminate, the layer formed should be improved both in terms of corrosion resistance and film adhesion.
Obgleich bei den bekannten Verfahren der Gehalt an sechswertigem Chrom infolge einer Reaktion mit dem Harz in gewissem Maße abnimmt, haftet ihnen der beträchtliche Nachteil an, daß ein großer Teil von sechswertigem Chrom nicht reduziert wird. Je nach Verwendung des beschichteten Materials kann in der Folge sechswertiges Chrom aus der Schicht herausgelöst werden, so daß der Einsetzbarkeit des entsprechend beschichteten Bleches Grenzen gesetzt sind.Although in the known processes the hexavalent chromium content decreases to some extent as a result of reaction with the resin, they suffer from the considerable disadvantage that a large part of hexavalent chromium is not reduced. Depending on the use of the coated material, hexavalent chromium can subsequently be removed from the layer, so that the usability of the correspondingly coated sheet is limited.
Aufgabe der Erfindung ist es, ein Verfahren zur Erzeugung von korrosionsschützenden Überzügen auf Oberflächen von von Aluminium verschiedenen Metallen bereitzustellen, daß den vorgenannten Nachteil nicht aufweist und zu Überzügen führt, aus denen selbst bei langwährendem Kontakt mit wässrigen Lösungen praktisch kein sechswertiges Chrom herauslösbar ist.The object of the invention is to provide a process for producing corrosion-protective coatings on surfaces of metals other than aluminum, which does not have the aforementioned disadvantage and leads to coatings from which practically no hexavalent chromium can be removed even in the case of long-term contact with aqueous solutions.
Die Aufgabe wird gelöst, indem das Verfahren der eingangs genannten Art entsprechend der Erfindung derart ausgestaltet wird, daß man ein Überzugsmittel auftrocknet und erhitzt, daß zusätzlich wasserlösliche organische Verbindung mit einem Siedepunkt von mehr als 100°C enthält, wobei die organische Verbindung mindestens eine -CH₂OH- und/oder mindestens eine = CHOH-Gruppe und - sofern nur eine dieser Gruppen im Molekül vorhanden ist - mindestens eine Äthergruppe (-0-) aufweist.The object is achieved in that the method of the type mentioned according to the invention is designed in such a way that a coating agent is dried and heated, that additionally contains water-soluble organic compound with a boiling point of more than 100 ° C., the organic compound at least one -CH₂OH- and / or at least one = CHOH group and - if only one of these groups is present in the molecule - has at least one ether group (-0-).
Das innerhalb der vorliegenden Erfindung einzusetzende schichtbildende organische Polymer muß wasserlöslich oder wasserdispergierbar sein und durch Erhitzen/Trocknen gehärtet werden können. Geeignete Beispiele für derartige Polymere sind in der JP-B-58-47230 (1983) (CA 87, Nr. 2 7657z) beschrieben. Hierbei sind Polymere auf Basis Acrylsäure bzw. Acrylat oder aber von Methacrylsäure oder Methacrylat oder Copolymere hiervon von besonderer Bedeutung.The layer-forming organic polymer to be used in the present invention must be water-soluble or water-dispersible and must be capable of being cured by heating / drying. Suitable examples of such polymers are described in JP-B-58-47230 (1983) (CA 87, No. 2,7657z). Polymers based on acrylic acid or acrylate or of methacrylic acid or methacrylate or copolymers thereof are of particular importance.
Das sechswertige Chrom kann z.B. als wasserfreie Chromsäure oder Ammoniumbichromat eingebracht werden. Insbesondere bei der Behandlung von Zinkoberflächen, wie von verzinktem Stahlblech kann ein Zusatz kleinerer Mengen dreiwertiges Chrom vorteilhaft sein.The hexavalent chromium can e.g. be introduced as anhydrous chromic acid or ammonium bichromate. In particular in the treatment of zinc surfaces, such as galvanized steel sheet, the addition of smaller amounts of trivalent chromium can be advantageous.
Gemäß einer bevorzugten Ausgestaltung der Erfindung werden als wasserlösliche organische Verbindung mit mindestens einer -CH₂OH- bzw. = CHOH-Gruppe, die für den Fall, daß nur eine dieser Gruppen vorhanden ist, auch eine Äthergruppe aufweisen muß, Äthylenglykol, Diäthylenglykol, Triäthylenglykol, Äthylenglykolmonomäthyläther, Diäthylenglykolmonomäthyläther, Propylenglykol, Dipropylenglykol, Butandiol, Hexandiol oder Glyzerin zugesetzt.According to a preferred embodiment of the invention as a water-soluble organic compound having at least one -CH₂OH- or = CHOH group, which in the event that only one of these groups is present, must also have an ether group, ethylene glycol, diethylene glycol, triethylene glycol, ethylene glycol monomethyl ether , Diethylene glycol monomethyl ether, propylene glycol, dipropylene glycol, butanediol, hexanediol or glycerin added.
Wenn das Überzugsmittel auf Wasserbasis mit einer wasserlöslichen organischen Verbindung der o.g. Art versetzt und auf der Metalloberfläche aufgetrocknet worden ist, ist im Vergleich zu einem Überzugsmittel ohne Zusatz einer derartigen organischen Verbindung ein Herauslösen von sechswertigem Chrom als Folge eines Kontakts mit Wasser praktisch nicht mehr feststellbar.If the water-based coating agent with a water-soluble organic compound of the above kind has been added and dried on the metal surface, compared to a coating agent without the addition of such an organic compound, a removal of hexavalent chromium as a result of contact with water is practically no longer detectable.
Eine bevorzugte Weiterbildung der Erfindung besteht darin, ein Überzugsmittel aufzutrocknen und zu erhitzen, daß die wasserlösliche organische Verbindung in einer Menge von 0,1 bis 20 g/l vorzugsweise von 0,5 bis 10 g/l enthält. Bei dieser Mengenangabe beträgt das Molverhältnis von organischer Verbindung zu sechswertigem Chrom etwa 0,1 bis 3, vorzugsweise 0,33 bis 1,5.A preferred development of the invention consists in drying and heating a coating agent that contains the water-soluble organic compound in an amount of 0.1 to 20 g / l, preferably 0.5 to 10 g / l. In this quantity, the molar ratio of organic compound to hexavalent chromium is approximately 0.1 to 3, preferably 0.33 to 1.5.
Eine weitere zweckmäßige Ausführungsform der Erfindung sieht vor, daß auf die Metalloberfläche aufgebrachte Überzugsmittel bei einer Temperatur im Bereich von 100 bis 300° zu erhitzen.Another expedient embodiment of the invention provides for the coating agent applied to the metal surface to be heated at a temperature in the range from 100 to 300 °.
Die Wirkungsweise der zuzusetzenden wasserlöslichen organischen Verbindung ist nicht eindeutig. Vermutlich wird diese Verbindung durch das sechswertige Chrom in der Überzugsmittelschicht zu dreiwertigem Chrom, dessen Löslichkeit geringer als die von sechswertigem Chrom ist, reduziert. Das dreiwertige Chrom wiederum reagiert mit dem Oxidationsprodukt der zugesetzten wasserlöslichen Verbindung oder dem wasserlöslichen oder wasserdispergierbaren organischen Polymer und bildet eine komplexe Verbindung, die praktisch kein Chrom mehr freisetzt. Aufgrund der schwachen Reduktionswirkung bei Raumtemperatur kann das fertig formulierte Überzugsmittel bei Raumtemperatur stabil gelagert werden. Die volle Wirkung der Reduktion des sechswertigen Chroms tritt erst während des Erhitzens/Trocknens der beschichteten Metalloberfläche ein. Die Stabilität des Überzugsmittels bei Raumtemperatur kann noch verbessert werden, wenn man den PH-Wert durch Einsatz von Ammoniumbichromat auf einem geringfügig höheren Wert hält.The mode of action of the water-soluble organic compound to be added is not clear. This compound is presumably reduced by the hexavalent chromium in the coating agent layer to trivalent chromium, the solubility of which is lower than that of hexavalent chromium. The trivalent chromium in turn reacts with the oxidation product of the added water-soluble compound or the water-soluble or water-dispersible organic polymer and forms a complex compound which practically no longer releases chromium. Due to the weak reduction effect at room temperature, the formulated coating agent can be stored stably at room temperature. The full The effect of the reduction of the hexavalent chromium only occurs during the heating / drying of the coated metal surface. The stability of the coating agent at room temperature can be further improved if the pH value is kept at a slightly higher value by using ammonium bichromate.
Der vorgenantte Effekt der Stabilität des Überzugsmittels bei Raumtemperatur und der vollen Reduktionswirkung bei höheren Temperaturen tritt nur dann ein, wenn die wasserlösliche organische Verbindung mindestens eine -CH₂OH- bzw. = CHOH-Gruppe und - falls nur eine dieser Gruppen im Molekül vorhanden ist - auch noch mindestens eine Äthergruppe aufweist und zudem die organische Verbindung einen Siedepunkt von mehr als 100°C besitzt.The aforementioned effect of the stability of the coating agent at room temperature and the full reduction effect at higher temperatures only occurs if the water-soluble organic compound contains at least one -CH₂OH- or = CHOH group and - if only one of these groups is present in the molecule - also still has at least one ether group and also the organic compound has a boiling point of more than 100 ° C.
Das erfindungsgemäße Verfahren eignet sich zur Behandlung einer Vielzahl von Metalloberflächen, ausgenommen Oberflächen aus Aluminium, wie Eisen, Stahl oder Zink. Das Verfahren ist mit besonderem Vorteil in anwendbar für die Erzeugung von korrosionsschützenden Überzügen auf verzinktem Stahl.The method according to the invention is suitable for treating a large number of metal surfaces, with the exception of surfaces made of aluminum, such as iron, steel or zinc. The method can be used with particular advantage for the production of corrosion-protective coatings on galvanized steel.
Die Erfindung wird anhand der folgenden Beispiele beispielsweise und näher erläutert.The invention is illustrated by the following examples, for example and in more detail.
Elektrolytisch verzinktes Stahlblech wurde mit einer wässrigen Lösung, enthaltend Natriumphosphat und Natriumsilikat als Hauptkomponenten, entfettet. Nach einer Wasserspülung wurde es mit einem wässrigen Überzugsmittel, daß 30 g/l wassserlösliches Acrylatharz (ber. als Trockensubstanz), 3,2 g/l Cr⁶⁺ und 1,0 g/r Cr³⁺ enthielt beschichtet. Nach einminütigem Trocknen bei 180°C wurde das Blech mit einer Auflage von 0,2 g/m² lackiert.Electrolytically galvanized steel sheet was degreased with an aqueous solution containing sodium phosphate and sodium silicate as the main components. After rinsing the water with an aqueous coating agent, coated that 30 g / l water-soluble acrylate resin (calc. as dry substance), 3.2 g / l Cr⁶⁺ and 1.0 g / r Cr³ beschichtet contained. After drying for one minute at 180 ° C., the sheet was coated with a coating of 0.2 g / m².
Wässrigen Überzugsmitteln der Zusammensetzung wie bei Vergleichsbeispiel 1 wurden 1,5 g/l Äthylenglykol bzw. 3 g/l Diäthylenglykol bzw. 2 g/l Propylenglykol zugesetzt. Die Behandlung der Prüfbleche erfolgte in der gleichen Weise wie im Vergleichsbeispiel angegeben.Aqueous coating compositions of the composition as in Comparative Example 1 were added with 1.5 g / l ethylene glycol or 3 g / l diethylene glycol or 2 g / l propylene glycol. The test panels were treated in the same manner as in the comparative example.
Feuerverzinktes Stahlblech, entfettet und mit Wasser gespült wurde wie im Fall von Vergleichsbeispiel 1 mit einem wässrigen Überzugsmittel von 10 g/l Polyacrylamid (ber. als Trockensubstanz) und 3,8 g/l Ammoniumbichromat beschichtet. Nach dreiminütigem Trocknen bei 180°C wurde es mit einem Auflagegewicht von 0,2 g/m² lackiert.Hot-dip galvanized steel sheet, degreased and rinsed with water, as in the case of Comparative Example 1, was coated with an aqueous coating agent of 10 g / l polyacrylamide (calc. As dry substance) and 3.8 g / l ammonium bichromate. After drying for three minutes at 180 ° C, it was coated with a coating weight of 0.2 g / m².
Wässrigen Überzugsmitteln der Zusammensetzung wie im Vergleichsbeispiel 2 wurden 2 g/l Hexandiol bzw. 4 g/l Glyzerin zugesetzt. Anschließend geschah die Behandlung der Bleche in der gleichen Weise wie im Vergleichsbeispiel 2 angegeben.2 g / l hexanediol or 4 g / l glycerin were added to aqueous coating compositions of the composition as in Comparative Example 2. Thereafter, the treatment of the sheets was carried out in the same manner as that given in Comparative Example 2.
Es wurde die im Vergleichsbeispiel 1 dargelegte Behandlung wiederholt, jedoch kam ein Überzugsmittel zum Einsatz, daß anstelle von Acrylatharz ein Copolymer aus Methacrylsäure, N-Methylolacrylamid, N-Butylacrylat und Metylmethacrylat im Verhältnis 4:2:100:100 enthielt.The treatment set out in Comparative Example 1 was repeated, but a coating agent was used which instead of acrylate resin contained a copolymer of methacrylic acid, N-methylolacrylamide, N-butyl acrylate and methyl methacrylate in a ratio of 4: 2: 100: 100.
Dem Überzugsmittel gemäß Vergleichsbeispiel 3 wurden 1,5 g/l Äthylenglykol zugesetzt. Ansonsten erfolgte die Behandlung der Prüfbleche wie in Vergleichsbeispiel 3.1.5 g / l of ethylene glycol were added to the coating agent according to Comparative Example 3. Otherwise, the test panels were treated as in Comparative Example 3.
Im Anschluß an die Aufbringung der organischen Beschichtung wurden sämtliche Prüfbleche Tests zur Ermittlung der Korrosionsbeständigkeit und der herauslösbaren Chrommenge unterworfen. Die Korrosionsbeständigkeit wurde durch den Salzsprühtest gemäß JIS Z-2371 bis zur Weißrostbildung auf 5 % der Blechoberfläche bestimmt.Following the application of the organic coating, all test panels were subjected to tests to determine the corrosion resistance and the amount of chromium which can be removed. The corrosion resistance was determined by the salt spray test according to JIS Z-2371 until white rust formation on 5% of the sheet surface.
Zur Ermittlung der herauslösbaren Chrommenge wurden aus dem Prüfblech Prüfkörper von 1 cm² herausgeschnitten, die bei 30°C für sieben Tage in 100 ml vollentsalztes Wasser getaucht wurden. Anschließend wurden die Prüfkörper mit voll entsalztem Wasser gespült. Lösung und Spülwasser wurden vereinigt und auf 50 ml konzentriert. Die Messung der Chromkonzentration erfolgte nach dem Prinzip der Atomabsorptions-Spektrometrie.To determine the amount of chromium that can be removed, test specimens of 1 cm² were cut out, which were immersed in 100 ml of demineralized water at 30 ° C. for seven days. The test specimens were then rinsed with demineralized water. Solution and rinse water were combined and concentrated to 50 ml. The chromium concentration was measured on the principle of atomic absorption spectrometry.
Während die Korrosionsbeständigkeit in sämtlichen Beispielen über einer Salzsprühdauer von 120 h lag, waren die herausgelösten Chrommengen sehr verschieden. Wie die nachfolgende Tabelle zeigt, waren die Werte für die nach den Vergleichsversuchen 1, 2 und 3 behandelten Bleche mit 2,5 bzw. 1,8 bzw. 2,3 mg/m² beträchtlich hoch.While the corrosion resistance in all examples was over a salt spray duration of 120 h, the amounts of chromium extracted were very different. As the following table shows, the values for the sheets treated according to comparative experiments 1, 2 and 3 were considerably high at 2.5, 1.8 and 2.3 mg / m².
Die nach dem erfindungsgemäßen Verfahren behandelten Bleche (Beispiel 1 bis 6) lieferten mit herauslösbaren Chrommengen von kleiner 0,20 bzw. kleiner 0,25 bzw. kleiner 0,30 mg/m² hervorragende Ergebnisse.
Claims (5)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31581786A JPS63168474A (en) | 1986-12-29 | 1986-12-29 | Coating method to impart corrosion resistance |
| JP315817/86 | 1986-12-29 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0273408A2 true EP0273408A2 (en) | 1988-07-06 |
| EP0273408A3 EP0273408A3 (en) | 1989-02-08 |
Family
ID=18069913
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP87119190A Withdrawn EP0273408A3 (en) | 1986-12-29 | 1987-12-24 | Process for producing coatings on metal surfaces |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0273408A3 (en) |
| JP (1) | JPS63168474A (en) |
| DE (1) | DE3744033A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5001173A (en) * | 1987-05-11 | 1991-03-19 | Morton Coatings, Inc. | Aqueous epoxy resin compositions and metal substrates coated therewith |
| US5082698A (en) * | 1987-05-11 | 1992-01-21 | Morton Coatings, Inc. | Aqueous epoxy resin compositions and metal substrates coated therewith |
| US5321061A (en) * | 1992-06-29 | 1994-06-14 | Morton Coatings, Inc. | Universally paintable passivated galvanized steel |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3053693A (en) * | 1958-05-29 | 1962-09-11 | Pennsalt Chemicals Corp | Metal coating with hexavalent chromium compound |
| GB1126045A (en) * | 1964-09-30 | 1968-09-05 | Pennsalt Chemicals Corp | Acrylic polymer coating formulations |
| FR1600545A (en) * | 1967-12-23 | 1970-07-27 | ||
| JPS54134043A (en) * | 1978-04-10 | 1979-10-18 | Kawasaki Steel Co | Electromagnetic steel plate having excellent volume ratio* punching property* and weldability for use as laminated ironcore |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5921349B2 (en) * | 1976-10-06 | 1984-05-19 | 大日本インキ化学工業株式会社 | Resin composition for powder coating |
| JPS56135565A (en) * | 1980-03-27 | 1981-10-23 | Nippon Dakuro Shamrock:Kk | Corrosionproof coat composition |
| JPS58174582A (en) * | 1982-04-05 | 1983-10-13 | Nippon Paint Co Ltd | Weldable painted steel plate |
| JPS6050228A (en) * | 1983-08-29 | 1985-03-19 | Nissan Koki Kk | Turbosupercharging device for internal-combustion engine |
| JPS61211373A (en) * | 1985-03-14 | 1986-09-19 | Toyota Central Res & Dev Lab Inc | Water paint composition and method for forming coating film |
-
1986
- 1986-12-29 JP JP31581786A patent/JPS63168474A/en active Pending
-
1987
- 1987-12-24 EP EP87119190A patent/EP0273408A3/en not_active Withdrawn
- 1987-12-24 DE DE19873744033 patent/DE3744033A1/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3053693A (en) * | 1958-05-29 | 1962-09-11 | Pennsalt Chemicals Corp | Metal coating with hexavalent chromium compound |
| GB1126045A (en) * | 1964-09-30 | 1968-09-05 | Pennsalt Chemicals Corp | Acrylic polymer coating formulations |
| FR1600545A (en) * | 1967-12-23 | 1970-07-27 | ||
| JPS54134043A (en) * | 1978-04-10 | 1979-10-18 | Kawasaki Steel Co | Electromagnetic steel plate having excellent volume ratio* punching property* and weldability for use as laminated ironcore |
Non-Patent Citations (1)
| Title |
|---|
| CHEMICALS ABSTRACTS, Band 92, Nr. 18, 5. Mai 1980, Zusammenfassung Nr. 151249p, Columbus, Ohio, US; & JP-A-79 134 043 (KAWASAKI STEEL CORP.) 18-10-1979 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5001173A (en) * | 1987-05-11 | 1991-03-19 | Morton Coatings, Inc. | Aqueous epoxy resin compositions and metal substrates coated therewith |
| US5082698A (en) * | 1987-05-11 | 1992-01-21 | Morton Coatings, Inc. | Aqueous epoxy resin compositions and metal substrates coated therewith |
| US5321061A (en) * | 1992-06-29 | 1994-06-14 | Morton Coatings, Inc. | Universally paintable passivated galvanized steel |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0273408A3 (en) | 1989-02-08 |
| DE3744033A1 (en) | 1988-07-07 |
| JPS63168474A (en) | 1988-07-12 |
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