EP0031103B1 - Method for the pretreatment of metal surfaces prior to phosphatizing - Google Patents
Method for the pretreatment of metal surfaces prior to phosphatizing Download PDFInfo
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- EP0031103B1 EP0031103B1 EP80107866A EP80107866A EP0031103B1 EP 0031103 B1 EP0031103 B1 EP 0031103B1 EP 80107866 A EP80107866 A EP 80107866A EP 80107866 A EP80107866 A EP 80107866A EP 0031103 B1 EP0031103 B1 EP 0031103B1
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- Prior art keywords
- solutions
- treated
- cleaning
- phosphating
- alkali metal
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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
- C23C22/78—Pretreatment of the material to be coated
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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
- C23C22/78—Pretreatment of the material to be coated
- C23C22/80—Pretreatment of the material to be coated with solutions containing titanium or zirconium compounds
Definitions
- the invention relates to an improved method for cleaning, degreasing and activating metal surfaces, in particular surfaces made of iron and steel and corresponding composite parts with aluminum and zinc, before a subsequent treatment thereof for the layer-forming phosphating.
- Such cleaning solutions generally contain surface-active substances, such as wetting agents and emulsifiers, and, to reinforce the emulsifying, saponification and dirt-carrying capacity, so-called builder substances, for example sodium hydroxide, alkali metal carbonates, alkali metal orthophosphates, corresponding condensed phosphates, such as sodium pyrophosphate or sodium triphosphate, and, if appropriate, also Silicates and borates.
- builder substances for example sodium hydroxide, alkali metal carbonates, alkali metal orthophosphates, corresponding condensed phosphates, such as sodium pyrophosphate or sodium triphosphate, and, if appropriate, also Silicates and borates.
- cleaning and degreasing solutions are often added to substances that have a layer-refining and activating effect, for example titanium phosphates.
- a characteristic feature of such solutions is their content of those builder substances which require free alkalinity in aqueous solution - that is to say whose alkalinity exceeds that of secondary orthophosphate - and a content of condensed phosphates.
- the pH of these cleaning solutions is in the range from 8.5 to 11.5.
- the cleaners described above have a number of serious disadvantages.
- the material to be treated usually passes through a rinsing zone following the cleaning zone and is then introduced into the phosphating zone.
- the material first comes into contact with the so-called pre-spray from the first spray ring in the phosphating zone.
- the rinsing water solution adhering to the metal surface - still contaminated with an alkaline cleaning solution - is washed off by the phosphating solution, while at the same time the formation of the phosphate layer begins.
- the object of the present invention is therefore to develop a method for pretreating metal surfaces before phosphating, in which the disadvantages of the cleaning solution described above, which have a negative effect on the subsequent phosphating, are avoided.
- the surfaces are treated with solutions which have a pH in the range from 6.5 to 8.0.
- the cleaning solutions to be used in the process according to the invention contain as builder components mainly alkali metal or ammonium salts of the primary and / or secondary orthophosphate, the content of primary or secondary phosphate primarily depending on the pH of the cleaning solution - within the scope of limits mentioned above - depends.
- the surfaces are treated with solutions whose pH is adjusted by adding phosphoric acid.
- alkali metal borates such as the diumtrium tetraborate
- alkali metal bicarbonates for example sodium hydrogen carbonate
- the metal surfaces are treated according to the invention with solutions which contain alkali metal borates and / or - at pH values of the solutions in the range from 7 to 8 - alkali metal hydrogen carbonates.
- the latter carbonates are expediently only used in neutral or weakly alkaline solutions, since acidic cleaning solutions would cause these active ingredients to decompose.
- Condensed phosphates for example tetrasodium pyrophosphate and / or pentasodium triphosphate, are used as builder substances according to the invention only to the extent that they are required to compensate for the water hardness of the process water used to prepare the cleaning solution.
- the cleaning solutions used for treating the metal surfaces do not contain any condensed phosphates.
- hydroxypolycarboxylic acid such as citric acid
- aminopolycarboxylic acids such as nitrilotriacetic acid or ethylenediaminetetraacetic acid
- phosphonic acids such as ethane-1-hydroxy-1,1-diphosphonic acid or aminotrimethylenephosphonic acid
- the metal surfaces are treated with cleaning solutions which contain other compounds which complex calcium ions.
- the cleaning solutions to be used according to the invention are customary anionic, cationic or nonionic wetting agents and emulsifiers.
- the nonionic types are preferably used, for example addition products of ethylene oxide with fatty alcohols, alkylphenols, fatty amines or polyoxypropylene glycols.
- the layer refiners and activators for example titanium phosphates, which are customary and known for this purpose, can also be added to the cleaning solutions.
- Such an activating agent is described in DE-AS-2038105, which can also be used for the purposes of the method according to the invention can preferably be used.
- This activating agent consists essentially of titanium salt, disodium orthophosphate and gelatin or alkali metal or ammonium salts of polyuronic acids.
- the cleaning solutions contain the usual components mentioned in the usual concentrations.
- the cleaning solutions described above are generally used in the process according to the invention in the manner known and customary for cleaning and degreasing processes. This means that the cleaning solutions can be applied to the metal surfaces to be treated both in a pointed or immersion and in a combined spray / immersion process.
- the temperature of the cleaning solution is usually in the range of about 40 to 70 ° C.
- the metal surfaces for which the method according to the invention can preferably be used include, in particular, those made of iron and steel and also composite parts of iron and steel with aluminum and / or zinc, as are frequently used, for example, in automobile body construction.
- the metal surfaces are generally rinsed after cleaning and then subjected to a layer-forming phosphating process - likewise in a known manner.
- Oiled iron sheet strips of the deep drawing grade ST 1405 were treated for 2 minutes under 1.5 bar spray pressure with a cleaning solution which had a temperature of 60 ° C. and contained 2.5 g / l of a cleaning agent mixture of the following composition:
- the pH of the cleaning solution was 7.4.
- the cleaned and degreased iron sheet strips were rinsed with an incorporated rinsing water containing 0.07 g / l of the detergent mixture, corresponding to 3 J / M 2 fresh water supply, and then moved into the phosphating zone at a throughput rate of 1 meter / minute.
- the iron sheet strips were phosphated by spraying on a phosphating solution for 3 minutes at an injection pressure of 0.8 bar and a bath temperature of 65 ° C., the solution containing 3 percent by weight of a concentrate of the following composition:
- the ratio of total acid to free acid in the phosphating solution was adjusted to a value of 10 by adding dilute sodium hydroxide solution and a nitrite concentration of 0.015% by weight was also maintained by adding sodium nitrite.
- the sheets were then rinsed thoroughly with deionized water, dried and then an optical assessment of the phosphating layer formed was carried out.
- the formation of the layer turned out to be perfectly good; that is, the layer was closed and even.
- Example 1 the procedure in the following examples was analogous to that in Example 1. These examples differ from Example 1 in the composition of the cleaning solution used and - as the attached comparative examples show - possibly in the formation of the phosphating layer.
- composition of the detergent mixture is a composition of the detergent mixture:
- pH value of the cleaning solution 7.8 Formation of the phosphating layer: perfect; extraordinarily even, closed and hard.
- composition of the detergent mixture pH value of the cleaning solution: 6.7
- Formation of the phosphating layer perfect; extraordinarily even, closed, closed and hard.
- composition of the detergent mixture nice:
- pH value of the cleaning solution 6.5
- Formation of the phosphating layer perfect; extraordinarily even, closed and hard.
- composition of the detergent mixture is a composition of the detergent mixture:
- pH value of the cleaning solution 9.0
- Formation of the phosphating layer inhomogeneous, torn open in an island shape, partly blue passivation layers (iron phosphate).
- composition of the detergent mixture is a composition of the detergent mixture:
- pH value of the cleaning solution 11.0 Formation of the phosphating layer: completely uneven and streaky, strong appearance of blue passivation layers (iron phosphate).
Description
Die Erfindung betrifft ein verbessertes Verfahren zum Reinigen, Entfetten und Aktivieren von Metalloberflächen, insbesondere von Oberflächen aus Eisen und Stahl sowie entsprechenden Verbundteilen mit Aluminium und Zink, vor einer nachfolgenden Behandlung derselben zum schichtbildenden Phosphatieren.The invention relates to an improved method for cleaning, degreasing and activating metal surfaces, in particular surfaces made of iron and steel and corresponding composite parts with aluminum and zinc, before a subsequent treatment thereof for the layer-forming phosphating.
Verfahren zur Erzeugung von Phosphatschichten auf Eisen- und Stahloberflächen mit Hilfe saurer Lösungen, die Phosphate mehrwertiger Metalle sowie - zur Beschleunigung der Schichtausbildung - Oxidationsmittel oder andere Beschleunigerkomponenten enthalten, sind seit langem bekannt. Nach der Art ihrer Anwendung unterscheidet man hierbei zwischen Spritz-, Tauch- oder kombinierten Spritz/Tauch-Verfahren. Gleichfalls bekannt ist die Verwendung alkalisch eingestellter Reinigungs- und Entfettungslösungen vor dem Phosphatieren, um die zu behandelnden Metalloberflächen insbesondere von anhaftenden Ölen und Fetten sowie anderen, auch mechanischen Verunreinigungen zu befreien. Derartige Reinigungslösungen enthalten in der Regel grenzflächenaktive Substanzen, wie Netzmittel und Emulgatoren, sowie zur Verstärkung des Emulgier-, Verseifungs- und Schmutztragevermögens sogenannte Builder- Substanzen, beispielsweise Natriumhydroxid, Alkalimetallcarbonate, Alkalimetallorthophosphate, entsprechende kondensierte Phosphate, wie das Natriumpyrophosphat oder Natriumtriphosphat, sowie gegebenenfalls auch Silikate und Borate. Ferner werden solche Reinigungs-und Entfettungslösungen häufig schichtverfeinernd und aktivierend wirkende Substanzen, zum Beispiel Titanphosphate, zugesetzt. Ein charakteristisches Merkmal derartiger Lösungen ist ihr Gehalt an solchen Builder-Substanzen, die eine freie Alkalität in wäßriger Lösung bedingen - das heißt, deren Alkalität diejenige von sekundärem Orthophosphat übersteigt - sowie ein Gehalt an kondensierten Phosphaten. Bei den gebräuchlichen Anwendungskonzentrationen liegt der pH-Wert dieser Reinigungslösungen im Bereich von 8,5 bis 11,5.Processes for producing phosphate layers on iron and steel surfaces with the aid of acidic solutions which contain phosphates of polyvalent metals and - to accelerate the formation of layers - contain oxidizing agents or other accelerator components have been known for a long time. Depending on the type of application, a distinction is made between spraying, dipping or combined spraying / dipping processes. It is also known to use alkaline cleaning and degreasing solutions before phosphating in order to free the metal surfaces to be treated, in particular from adhering oils and greases, as well as other, also mechanical, impurities. Such cleaning solutions generally contain surface-active substances, such as wetting agents and emulsifiers, and, to reinforce the emulsifying, saponification and dirt-carrying capacity, so-called builder substances, for example sodium hydroxide, alkali metal carbonates, alkali metal orthophosphates, corresponding condensed phosphates, such as sodium pyrophosphate or sodium triphosphate, and, if appropriate, also Silicates and borates. Furthermore, such cleaning and degreasing solutions are often added to substances that have a layer-refining and activating effect, for example titanium phosphates. A characteristic feature of such solutions is their content of those builder substances which require free alkalinity in aqueous solution - that is to say whose alkalinity exceeds that of secondary orthophosphate - and a content of condensed phosphates. At the usual application concentrations, the pH of these cleaning solutions is in the range from 8.5 to 11.5.
Im Hinblick auf die nachfolgende Phosphatierung weisen die vorstehend beschriebenen Reiniger jedoch eine Reihe schwerwiegender Nachteile auf. Üblicherweise durchläuft das Behandlungsgut im Anschluß an die Reinigungszone zunächst eine Spülzone und wird sodann in die Phosphatierzone eingeführt. Bei Spritz- oder kombinierten Spritz/Tauch-Anlagen kommt das Gut hier zuerst mit dem sogenannten Vorspray aus dem ersten Sprühring der Phosphatierungszone in Berührung. In dieser Phase wird die an der Metalloberfläche haftende - noch mit alkalischer Reinigungslösung verunreinigte - Spülwasserlösung durch die Phosphatierlösung abgewaschen, während gleichzeitig die Ausbildung der Phosphatschicht ihren Anfang nimmt. Hierbei treten nun insofern Probleme auf, als der zunächst im alkalischen Bereich liegende pH-Wert der Spülwasserlösung sukzessiv an der Metalloberfläche bis auf den sauren pH-Wert der Phosphatierungslösung abgesenkt wird, wobei auch pH-Werte im Bereich vom 6,5 bis 4,5 durchlaufen werden. in diesem pH-Bereich ist jedoch bevorzugt die Bildung passivierender Eisenphosphatschichten zu beobachten, die wiederum die nachfolgend angestrebte schichtbildende Phosphatierung in stärkstem Maße beeinträchtigen und behindern. Zusätzliche, Störungen der Schichtausbildung resultieren gleichermaßen durch die Verwendung kondensierter Phosphate im Reiniger, da diese starke Phosphatierungsgifte darstellen. Derartige Störungen, die einerseits durch die Alkalität der verschleppten Reinigerlösungen sowie andererseits durch deren Gehalt an kondensierten Phosphaten hervorgerufen werden, äußern sich in streifigen, fleckigen, passivierten Phosphatierungsschichten, deren Schichtgewicht zudem starke Schwankungen aufweist. Ferner bedingen diese inhomogenen Schichten nur einen mangelhaften Korrosionsschutz der Metalloberfläche, insbesondere in Verbindung mit nachfolgend aufgebrachten organischen Beschichtungen, wie Elektrotauchbeschichtungen.With regard to the subsequent phosphating, however, the cleaners described above have a number of serious disadvantages. The material to be treated usually passes through a rinsing zone following the cleaning zone and is then introduced into the phosphating zone. In the case of spraying or combined spraying / immersion systems, the material first comes into contact with the so-called pre-spray from the first spray ring in the phosphating zone. In this phase, the rinsing water solution adhering to the metal surface - still contaminated with an alkaline cleaning solution - is washed off by the phosphating solution, while at the same time the formation of the phosphate layer begins. Problems arise here in that the pH value of the rinsing water solution, which is initially in the alkaline range, is successively reduced on the metal surface to the acidic pH value of the phosphating solution, pH values also in the range from 6.5 to 4.5 be run through. in this pH range, however, the formation of passivating iron phosphate layers can preferably be observed, which in turn adversely affect and hinder the subsequent layer-forming phosphating to the greatest extent. Additional, disturbances in the layer formation result equally from the use of condensed phosphates in the cleaner, since these are strong phosphating poisons. Such disturbances, which are caused on the one hand by the alkalinity of the carried-away cleaning solutions and on the other hand by their content of condensed phosphates, are manifested in streaky, spotty, passivated phosphating layers, the layer weight of which also shows strong fluctuations. Furthermore, these inhomogeneous layers only provide inadequate protection against corrosion of the metal surface, in particular in connection with subsequently applied organic coatings, such as electro-dip coatings.
Die vorstehend erörterten negativen Einflüsse der Reinigungslösung auf die Phosphatierung wirken sich um so stärker aus, je geringer die Durchlaufgeschwindigkeit des Behandlungsgutes durch die Behandlungszonen und je größer damit dessen Verweilzeit in der kritischen Vorspray-Zone ist. Aus produktionstechnischen Gründen kann jedoch die Durchlaufgeschwindigkeit des Gutes nicht beliebig gesteigert werden. Als außerordentlich nachteilig erweisen sich die gebräuchlichen Reinigerlösungen ferner im Hinblick auf die in zunehmendem Maße zur Anwendung gelangenden Verfahren mit wassersparenden Spülzonen - beispielsweise Kaskadenverfahren -, da bei diesen Arbeitsweisen immer stärkere Anreicherungen von Reinigerlösung in den Spülwässern in Kauf genommen werden müssen.The above-mentioned negative influences of the cleaning solution on the phosphating have an even greater effect, the lower the throughput speed of the material to be treated through the treatment zones and the greater its residence time in the critical pre-spray zone. However, the throughput speed of the goods cannot be increased arbitrarily for production reasons. The usual detergent solutions also prove to be extremely disadvantageous with regard to the increasingly used processes with water-saving rinsing zones - for example cascade processes - since with these working methods ever increasing concentrations of detergent solution in the rinsing water have to be accepted.
Die Aufgabe der vorliegenden Erfindung ist es daher, ein Verfahren zur Vorbehandlung von Metalloberflächen vor dem Phosphatieren zur entwickeln, bei dem die vorstehend beschriebenen Nachteile der Reinigerlösung, die sich auf die nachfolgende Phosphatierung in negativer Weise auswirken, vermieden werden.The object of the present invention is therefore to develop a method for pretreating metal surfaces before phosphating, in which the disadvantages of the cleaning solution described above, which have a negative effect on the subsequent phosphating, are avoided.
Gegenstand der Erfindung ist somit ein Verfahren zum Reinigen, Entfetten und Aktivieren von Metalloberflächen, insbesondere von Oberflächen aus Eisen und Stahl sowie entsprechende Verbundteilen mit Aluminium und Zink, vor einer nachfolgenden Behandlung derselben zum schichtbildenden Phosphatieren, bei erhöhten Temperaturen sowie mit Hilfe von Lösungen, die Alkalimetall- oder Ammoniumsalze des primären und/oder sekundären Orthophosphats sowie an sich bekannte Komponenten enthalten, , welches dadurch gekennzeichnet ist, daß man die Oberflächen mit solchen Lösungen behandelt, die
- a) einen pH-Wert im Bereich von 6,3 bis 8,2 sowie
- b) eine Alkalität als diejenige von Lösungen entsprechender sekundärer Phosphate gleicher Konzentration aufweisen
und die - c) kondensierte höchstens in einer Menge enthalten, die zur Kompensation der Wasserhärte des verwendeten Betriebswassers erforderlich ist.
- a) a pH in the range from 6.3 to 8.2 and
- b) have an alkalinity than that of solutions of corresponding secondary phosphates of the same concentration
and the - c) contain condensed at most in an amount necessary to compensate for the water hardness of the process water used.
Überraschenderweise wurde nämlich gefunden, daß sich mit Hilfe des vorstehend charakterisierten Reinigungs- und Entfettungsverfahrens sowohl ausgezeichnete Reinigungseffekte hinsichtlich der zu behandelnden Metalloberflächen als auch einwandfreie Phosphatierungsschichten bei der nachfolgenden Phosphatierung erzielen lassen. Bedingt durch die Wahl des erfindungsgemäß niederen pH-Bereiches der Reiniger, deren insgesamt verringerte freie Alkalität sowie deren möglichst geringen Gehalt an kondensierten Phosphaten, können die bislang zu beobachtenden Schwierigkeiten bei der schichtbildenden Phosphatierung vermieden werden, ohne daß hierunter die Qualität des angestrebten Reinigungserfolges Einbußen erleidet.Surprisingly, it was found that with the aid of the cleaning and degreasing process characterized above, both excellent cleaning effects with regard to the metal surfaces to be treated and flawless phosphating layers can be achieved in the subsequent phosphating. Due to the choice of the low pH range of the cleaners according to the invention, their overall reduced free alkalinity and their lowest possible level of condensed phosphates, the difficulties observed so far in the layer-forming phosphating can be avoided without the quality of the desired cleaning success suffering .
In diesem Sinne ist es bei dem Verfahren gemäß der Erfindung besonders bevorzugt, daß man die Oberflächen mit Lösungen behandelt, die einen pH-Wert im Bereich von 6,5 bis 8,0 aufweisen.In this sense, it is particularly preferred in the process according to the invention that the surfaces are treated with solutions which have a pH in the range from 6.5 to 8.0.
Die bei dem erfindungsgemäßen Verfahren zu verwendenden Reinigerlösungen enthalten als Builder-Komponenten in der Hauptsache Alkalimetall- oder Ammoniumsalze des primären und/oder sekundären Orthophosphats, wobei der Gehalt an primärem oder sekundärem Phosphat in erster Linie von dem pH-Wert der Reinigerlösung - im Rahmen der vorstehend genannten Grenzen - abhängt.The cleaning solutions to be used in the process according to the invention contain as builder components mainly alkali metal or ammonium salts of the primary and / or secondary orthophosphate, the content of primary or secondary phosphate primarily depending on the pH of the cleaning solution - within the scope of limits mentioned above - depends.
Zur Einstellung des gewünschten pH-Wertes kann es erforderlich sein, der Reinigerlösung zusätzlich sauer reagierende Substanzen - beispielsweise Phosphorsäure - zuzusetzen. Diese Maßnahme ist insbesondere im Hinblick auf einen möglichen Gehalt der Lösungen an weiteren, gegebenenfalls alkalischen Builderstoffen, die die freie Alkalität der Reinigerlösung über das erwünschte Maß hinaus erhöhen würden, von wesentlicher Bedeutung. Dementsprechend ist es im Sinne der Erfindung bevorzugt, daß man die Oberflächen mit Lösungen behandelt, deren pH-Wert durch Zugabe von Phosphorsäure eingestellt wird.To set the desired pH value, it may be necessary to add substances with an acidic reaction - for example phosphoric acid - to the cleaning solution. This measure is particularly important with regard to a possible content of the solutions in further, possibly alkaline builder substances, which would increase the free alkalinity of the cleaning solution beyond the desired level. Accordingly, it is preferred in the context of the invention that the surfaces are treated with solutions whose pH is adjusted by adding phosphoric acid.
Als weitere Buildersubstanzen für die Reinigerlösungen - die eine verbesserte Reinigungswirkung derselben bedingen - kommen insbesondere Alkalimetallborate, wie das Dina- 'triumtetraborat, und/oder Alkalimetallbicarbonate, beispielsweise Natriumhydrogencarbonat, in Frage. Dementsprechend behandelt man erfindungsgemäß die Metalloberflächen mit Lösungen, die Alkalimetallborate und/oder - bei pH-Werten der Lösungen im Bereich von 7 bis 8 - Alkalimetallhydrogencarbonate enthalten. Zweckmäßigerweise werden die letztgenannten Carbonate nur in neutralen oder schwach alkalischen Lösungen eingesetzt, da sauer eingestellte Reinigerlösungen eine Zersetzung dieser Wirkstoffe bedingen würden.Other builder substances for the cleaning solutions - which require an improved cleaning effect thereof - are, in particular, alkali metal borates, such as the diumtrium tetraborate, and / or alkali metal bicarbonates, for example sodium hydrogen carbonate. Accordingly, the metal surfaces are treated according to the invention with solutions which contain alkali metal borates and / or - at pH values of the solutions in the range from 7 to 8 - alkali metal hydrogen carbonates. The latter carbonates are expediently only used in neutral or weakly alkaline solutions, since acidic cleaning solutions would cause these active ingredients to decompose.
Kondensierte Phosphate, beispielsweise Tetranatriumpyrophosphat und/oder Pentanatriumtriphosphat, finden als Buildersubstanzen erfindungsgemäß nur in dem Maße Verwendung, als sie zur Kompensation der Wasserhärte des zum Ansetzen der Reinigerlösung verwendeten Betriebswassers erforderlich sind. Nach einer bevorzugten Ausführungsform des erfindungsgemäßen Verfahrens enthalten die zur Behandlung der Metalloberflächen verwendeten Reinigerlösungen keine kondensierten Phosphate. Überraschenderweise hat sich nämlich gezeigt, daß bei Anwendung des erfindungsgemäßen Verfahrens auch ohne Einsatz kondensierter Phosphate Wasserhärten bis zu 26° dH (Grad deutscher Härte) tolerierbar sind, ohne daß Störungen der nachfolgenden Phosphatierung, das heißt der Schichtausbildung, auftreten oder zu befürchten sind. Darüber hinaus können zur Kompensation der Wasserhärte anstelle von kondensierten Phosphaten gegebenenfalls auch sonstige Calciumionen komplexierende Verbindungen Verwendung finden, die für derartige Zwecke üblicherweise eingesetzt werden. Als solche kommen beispielsweise Hydroxypolycarbonsäure, wie Citronensäure, Aminopolycarbonsäuren, wie Nitrilotriessigsäure oder Ethylendiamintetraessigsäure Phosphonsäuren, wie Ethan-1-hydroxy-1,1-diphosphonsäure oder Aminotrimethylenphosphonsäure, die wasserlöslichen Alkalimetallsalze derartiger Säuren sowie sonstige gebräuchliche Komplexbildner in Frage. Dementsprechend ist es erfindungsgemäß bevorzugt, daß man die Metalloberflächen mit Reinigerlösungen behandelt, die sonstige Calciumionen komplexierende Verbindungen enthalten.Condensed phosphates, for example tetrasodium pyrophosphate and / or pentasodium triphosphate, are used as builder substances according to the invention only to the extent that they are required to compensate for the water hardness of the process water used to prepare the cleaning solution. According to a preferred embodiment of the method according to the invention, the cleaning solutions used for treating the metal surfaces do not contain any condensed phosphates. Surprisingly, it has been shown that, when using the process according to the invention, water hardnesses of up to 26 ° dH (degree of German hardness) can be tolerated even without the use of condensed phosphates, without disturbances in the subsequent phosphating, that is to say the layer formation, occurring or being feared. In addition, to compensate for the water hardness, instead of condensed phosphates, it is also possible, if appropriate, to use other compounds complexing calcium ions which are usually used for such purposes. As such, for example, hydroxypolycarboxylic acid, such as citric acid, aminopolycarboxylic acids, such as nitrilotriacetic acid or ethylenediaminetetraacetic acid, phosphonic acids, such as ethane-1-hydroxy-1,1-diphosphonic acid or aminotrimethylenephosphonic acid, the water-soluble alkali metal salts of such acids and other commonly used complexing agents are suitable. Accordingly, it is preferred according to the invention that the metal surfaces are treated with cleaning solutions which contain other compounds which complex calcium ions.
Weitere Bestandteile der erfindungsgemäß zu verwendenden Reinigerlösungen sind gebräuchliche anionaktive, kationaktive oder nichtionogene Netzmittel und Emulgatoren. Von diesen werden jedoch bevorzugt die nichtionogenen Typen eingesetzt, beispielsweise Anlagerungsprodukte des Ethylenoxids an Fettalkohole, Alkylphenole, Fettamine oder Polyoxypropylenglykole. Zur Aktivierung der zu behandelnden Metalloberflächen können den Reinigerlösungen ferner die für diesen Zweck gebräuchlichen und bekannten Schichtverfeinerer und Aktivatoren, beispielsweise Titanphosphate, zugesetzt werden. In der DE-AS-2038105 ist ein solches Aktivierungsmittel beschrieben, das auch im Sinne des erfindungsgemäßen Verfahrens bevorzugt Verwendung finden kann. Dieses Aktivierungsmittel besteht im wesentlichen aus Titansalz, Dinatriumorthophosphat und Gelatine oder Alkalimetall- beziehungsweise Ammoniumsalzen von Polyuronsäuren. Die Reinigerlösungen enthalten die genannten üblichen Bestandteile in den gebräuchlichen Konzentrationen.Further constituents of the cleaning solutions to be used according to the invention are customary anionic, cationic or nonionic wetting agents and emulsifiers. Of these, however, the nonionic types are preferably used, for example addition products of ethylene oxide with fatty alcohols, alkylphenols, fatty amines or polyoxypropylene glycols. To activate the metal surfaces to be treated, the layer refiners and activators, for example titanium phosphates, which are customary and known for this purpose, can also be added to the cleaning solutions. Such an activating agent is described in DE-AS-2038105, which can also be used for the purposes of the method according to the invention can preferably be used. This activating agent consists essentially of titanium salt, disodium orthophosphate and gelatin or alkali metal or ammonium salts of polyuronic acids. The cleaning solutions contain the usual components mentioned in the usual concentrations.
Die Anwendung der vorstehend beschriebenen Reinigerlösungen im Rahmen des erfindungsgemäßen Verfahrens erfolgt im allgemeinen in der für Reinigungs- und Entfettungsverfahren bekannten und gebräuchlichen Art und Weise. Dies bedeutet, daß die Reinigeriösungen sowohl im Spitz- oder Tauch- als auch im kombinierten Spritz/Tauch-Verfahren auf die zu behandelnden Metalloberflächen aufgebracht werden können. Die Temperatur der Reinigerlösung liegt hierbei üblicherweise im Bereich von etwa 40 bis 70°C. Zu den Metalloberflächen, für die das erfindungsgemäße Verfahren bevorzugt Anwendung finden kann, zählen insbesondere solche aus Eisen und Stahl sowie ferner Verbundteile von Eisen und Stahl mit Aluminium und/oder Zink, wie sie beispielsweise häufig im Automobilkarosseriebau eingesetzt werden. Wie bereits vorstehend erörtert, werden die Metalloberflächen nach erfolgter Reinigung in der Regel gespült und anschließend einem schichtbildenden Phsophatierungsverfahren - gleichfalls in bekannter Weise - unterworfen.The cleaning solutions described above are generally used in the process according to the invention in the manner known and customary for cleaning and degreasing processes. This means that the cleaning solutions can be applied to the metal surfaces to be treated both in a pointed or immersion and in a combined spray / immersion process. The temperature of the cleaning solution is usually in the range of about 40 to 70 ° C. The metal surfaces for which the method according to the invention can preferably be used include, in particular, those made of iron and steel and also composite parts of iron and steel with aluminum and / or zinc, as are frequently used, for example, in automobile body construction. As already discussed above, the metal surfaces are generally rinsed after cleaning and then subjected to a layer-forming phosphating process - likewise in a known manner.
Die nachstehenden Beispiele erläutern die Durchführung des erfindungsgemäßen Verfahrens sowie die Zusammensetzung entsprechender Reinigerlösungen.The following examples explain the implementation of the process according to the invention and the composition of corresponding cleaning solutions.
Geölte Eisenblechstreifen der Tiefziehgüte ST 1405 wurden für eine Dauer von 2 Minuten unter 1,5 bar Spritzdruck mit einer Reinigerlösung behandelt, die eine Temperatur von 60°C aufwies und 2,5 g/I eines Reinigungsmittelgemisches der folgenden Zusammensetzung enthielt:
Der pH-Wert der Reinigerlösung betrug 7,4.The pH of the cleaning solution was 7.4.
Anschließend wurden die gereinigten und entfetteten Eisenblechstreifen mit einem eingearbeiteten Spülwasser, das 0,07 g/I des Reinigungsmittelgemisches enthielt, - entsprechend 3 J/M 2 Frischwasserzulauf - gespült und sodann mit einer Durchlaufgeschwindigkeit von 1 Meter/Minute in die Phosphatierungszone eingefahren. Phosphatiert wurden die Eisenblechstreifen durch Aufsprühen einer Phosphatierungslösung für eine Dauer von 3 Minuten bei einem Spritzdruck von 0,8 bar und einer Badtemperatur von 65° C, wobei die Lösung 3 Gewichtsprozent eines Konzentrates der folgenden Zusammensetzung enthielt:Subsequently, the cleaned and degreased iron sheet strips were rinsed with an incorporated rinsing water containing 0.07 g / l of the detergent mixture, corresponding to 3 J / M 2 fresh water supply, and then moved into the phosphating zone at a throughput rate of 1 meter / minute. The iron sheet strips were phosphated by spraying on a phosphating solution for 3 minutes at an injection pressure of 0.8 bar and a bath temperature of 65 ° C., the solution containing 3 percent by weight of a concentrate of the following composition:
Das Verhältnis Gesamtsäure zu freier Säure in der Phosphatierungslösung wurde durch Zugabe von verdünnter Natronlauge auf einem Wert von 10 eingestellt und ferner eine Nitritkonzentration von 0,015 Gew.-% durch Zugabe von Natriumnitrit aufrechterhalten.The ratio of total acid to free acid in the phosphating solution was adjusted to a value of 10 by adding dilute sodium hydroxide solution and a nitrite concentration of 0.015% by weight was also maintained by adding sodium nitrite.
Anschließend wurden die Bleche gründlich mit entsalztem Wasser gespült, getrocknet und sodann eine optische Beurteilung der gebildeten Phosphatierungsschicht vorgenommen. Hierbei erwies sich die Ausbildung der Schicht als durchaus einwandfrei; das heißt, die Schicht war geschlossen und gleichmäßig.The sheets were then rinsed thoroughly with deionized water, dried and then an optical assessment of the phosphating layer formed was carried out. Here, the formation of the layer turned out to be perfectly good; that is, the layer was closed and even.
Soweit nicht anders vermerkt, wurde in den nachfolgenden Beispielen analog den Angaben in Beispiel 1 verfahren. Diese Beispiele unterscheiden sich von Beispiel 1 in der Zusammensetzung der verwendeten Reinigerlösung und - wie die angefügten Vergleichsbeispiele zeigen - gegebenenfalls in der Ausbildung der Phosphatierungsschicht.Unless otherwise noted, the procedure in the following examples was analogous to that in Example 1. These examples differ from Example 1 in the composition of the cleaning solution used and - as the attached comparative examples show - possibly in the formation of the phosphating layer.
Zusammensetzung des Reinigungsmittelgemisches:
pH-Wert der Reinigerlösung: 7,8 Ausbildung der Phosphatierungsschicht: einwandfrei; außerordentlich gleichmäßig, geschlossen und hart.pH value of the cleaning solution: 7.8 Formation of the phosphating layer: perfect; extraordinarily even, closed and hard.
Zusammensetzung des Reinigungsmittelgemisches:
Ausbildung der Phosphatierungsschicht: einwandfrei; außerordentlich gleichmäßig, ge- , schlossen und hart.Formation of the phosphating layer: perfect; extraordinarily even, closed, closed and hard.
Zusammensetzung des Reinigungsmittelgemi-! sches:
pH-Wert der Reinigerlösung: 6,5
Ausbildung der Phosphatierungsschicht: einwandfrei; außerordentlich gleichmäßig, geschlossen und hart.pH value of the cleaning solution: 6.5
Formation of the phosphating layer: perfect; extraordinarily even, closed and hard.
Zusammensetzung des Reinigungsmittelgemisches:
pH-Wert der Reinigerlösung: 9,0
Ausbildung der Phosphatierungsschicht: inhomogen, inselförmig aufgerissen, teilweise blaue Passivierungsschichten (Eisenphosphat).pH value of the cleaning solution: 9.0
Formation of the phosphating layer: inhomogeneous, torn open in an island shape, partly blue passivation layers (iron phosphate).
Zusammensetzung des Reinigungsmittelgemisches:
pH-Wert der Reinigerlösung: 11,0
Ausbildung der Phosphatierungsschicht: völlig ungleichmäßig und streifig, starkes Auftreten blauer Passivierungsschichten (Eisenphosphat).pH value of the cleaning solution: 11.0
Formation of the phosphating layer: completely uneven and streaky, strong appearance of blue passivation layers (iron phosphate).
Claims (6)
and which
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2951600 | 1979-12-21 | ||
| DE19792951600 DE2951600A1 (en) | 1979-12-21 | 1979-12-21 | METHOD FOR PRE-TREATING METAL SURFACES BEFORE PHOSPHATING |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0031103A1 EP0031103A1 (en) | 1981-07-01 |
| EP0031103B1 true EP0031103B1 (en) | 1983-09-28 |
Family
ID=6089186
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP80107866A Expired EP0031103B1 (en) | 1979-12-21 | 1980-12-12 | Method for the pretreatment of metal surfaces prior to phosphatizing |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4384900A (en) |
| EP (1) | EP0031103B1 (en) |
| JP (1) | JPS5693880A (en) |
| AT (1) | AT372116B (en) |
| BR (1) | BR8008327A (en) |
| CA (1) | CA1151497A (en) |
| DE (2) | DE2951600A1 (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4496470A (en) * | 1981-01-12 | 1985-01-29 | The B. F. Goodrich Company | Cleaning composition |
| CA1187771A (en) * | 1981-06-10 | 1985-05-28 | Timothy J.M. Treharne | Corrosion inhibition in sintered stainless steel |
| DE3213649A1 (en) * | 1982-04-14 | 1983-10-27 | Gerhard Collardin GmbH, 5000 Köln | METHOD FOR CLEANING AND GREASING AND ACTIVATING METAL SURFACES |
| FR2572422B1 (en) * | 1984-10-31 | 1993-03-05 | Produits Ind Cie Fse | IMPROVED ACTIVATION AND REFINING BATH FOR ZINC PHOSPHATATION PROCESS AND CONCENTRATE THEREOF |
| DE3541997A1 (en) * | 1985-11-28 | 1987-06-04 | Collardin Gmbh Gerhard | IMPROVED METHOD FOR ACTIVATING METAL SURFACES BEFORE ZINC PHOSPHATION |
| DE3814363A1 (en) * | 1988-04-28 | 1989-11-09 | Henkel Kgaa | TITANIUM-FREE ACTIVATING AGENTS, METHOD FOR THE PRODUCTION THEREOF AND THEIR USE FOR ACTIVATING METAL SURFACES BEFORE ZINC PHOSPHATING |
| DE3814287A1 (en) * | 1988-04-28 | 1989-11-09 | Henkel Kgaa | POLYMERS TITANIUM PHOSPHATES, METHOD FOR THE PRODUCTION THEREOF AND THEIR USE FOR ACTIVATING METAL SURFACES BEFORE ZINC PHOSPHATION |
| US7503940B2 (en) * | 2003-02-20 | 2009-03-17 | Harris Research, Inc. | Method and system for spot-dyeing textiles |
| JP5451965B2 (en) * | 2007-01-29 | 2014-03-26 | 株式会社神戸製鋼所 | Surface treatment agent for aluminum alloy |
| US20080283152A1 (en) * | 2007-05-17 | 2008-11-20 | Jeffrey Allen Greene | Rinse conditioner bath for treating a substrate and associated method |
| JP2009132993A (en) * | 2007-11-02 | 2009-06-18 | Mazda Motor Corp | Degreasing pretreatment method and apparatus therefor |
| CN114075663B (en) * | 2020-08-21 | 2023-09-12 | 宝山钢铁股份有限公司 | Water-based treating agent for carbon steel surface, well corrosion-resistant carbon steel and preparation method thereof |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DD3460A (en) * | ||||
| US2329065A (en) * | 1942-03-06 | 1943-09-07 | Westinghouse Electric & Mfg Co | Corrosion resistant coating for metal surfaces |
| US2345307A (en) * | 1943-03-19 | 1944-03-28 | American Cyanamid Co | Detergent composition |
| IT432445A (en) * | 1943-07-29 | |||
| GB743578A (en) * | 1952-05-19 | 1956-01-18 | Apv Co Ltd | Improvements in or relating to the cleaning of liquid treating or holding apparatus |
| US2874081A (en) * | 1956-08-02 | 1959-02-17 | Parker Rust Proof Co | Pretreatment solution for phosphate coating, method of preparing the same and process of treating metal surfaces |
| GB865497A (en) * | 1958-10-03 | 1961-04-19 | Pyrene Co Ltd | Improvements relating to the cleaning and phosphate coating of metallic surfaces |
| DE1105250B (en) * | 1958-12-10 | 1961-04-20 | Hoechst Ag | Agent for the simultaneous cleaning, degreasing and removal of the drawing material carrier layer from cold-formed stainless steel |
| US3255118A (en) * | 1961-12-29 | 1966-06-07 | Pennsalt Chemicals Corp | Aluminum cleaning compositions |
| SE366347B (en) * | 1970-06-01 | 1974-04-22 | Collardin Gmbh Gerhard | |
| US3864139A (en) * | 1970-12-04 | 1975-02-04 | Amchem Prod | Pretreatment compositions and use thereof in treating metal surfaces |
| US3888783A (en) * | 1973-10-10 | 1975-06-10 | Amchem Prod | Cleaner for tin plated ferrous metal surfaces, comprising phosphate, silicate and borax |
| JPS6017831B2 (en) * | 1976-12-30 | 1985-05-07 | アムケム プロダクツ インコ−ポレ−テツド | Composition and cleaning method for cleaning metal surfaces |
| US4152176A (en) * | 1978-08-07 | 1979-05-01 | R. O. Hull & Company, Inc. | Method of preparing titanium-containing phosphate conditioner for metal surfaces |
-
1979
- 1979-12-21 DE DE19792951600 patent/DE2951600A1/en not_active Withdrawn
-
1980
- 1980-12-12 DE DE8080107866T patent/DE3065089D1/en not_active Expired
- 1980-12-12 EP EP80107866A patent/EP0031103B1/en not_active Expired
- 1980-12-18 BR BR8008327A patent/BR8008327A/en unknown
- 1980-12-18 JP JP17815180A patent/JPS5693880A/en active Granted
- 1980-12-19 AT AT0620980A patent/AT372116B/en not_active IP Right Cessation
- 1980-12-19 CA CA000367202A patent/CA1151497A/en not_active Expired
- 1980-12-22 US US06/219,245 patent/US4384900A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5693880A (en) | 1981-07-29 |
| US4384900A (en) | 1983-05-24 |
| ATA620980A (en) | 1983-01-15 |
| DE3065089D1 (en) | 1983-11-03 |
| AT372116B (en) | 1983-09-12 |
| BR8008327A (en) | 1981-07-07 |
| EP0031103A1 (en) | 1981-07-01 |
| DE2951600A1 (en) | 1981-07-02 |
| CA1151497A (en) | 1983-08-09 |
| JPH028029B2 (en) | 1990-02-22 |
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