WO1999049104A1 - Method for cleaning aluminium surfaces - Google Patents

Method for cleaning aluminium surfaces Download PDF

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Publication number
WO1999049104A1
WO1999049104A1 PCT/EP1999/001662 EP9901662W WO9949104A1 WO 1999049104 A1 WO1999049104 A1 WO 1999049104A1 EP 9901662 W EP9901662 W EP 9901662W WO 9949104 A1 WO9949104 A1 WO 9949104A1
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Prior art keywords
aluminum
alkali metal
cleaning
weight
metal hydroxide
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PCT/EP1999/001662
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German (de)
French (fr)
Inventor
Steffen RÜSSE
Hans-Jörgen Rehm
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Henkel Kommanditgesellschaft Auf Aktien
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Publication of WO1999049104A1 publication Critical patent/WO1999049104A1/en

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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
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/14—Cleaning or pickling metallic material with solutions or molten salts with alkaline solutions
    • C23G1/22—Light metals

Definitions

  • the invention relates to a method for cleaning surfaces of aluminum or aluminum alloys.
  • Aluminum alloys are understood to mean those alloys which consist of at least 90% by weight of aluminum.
  • the method is designed for cleaning rail vehicles that have surfaces made of aluminum or aluminum alloys.
  • rail vehicles often consist of aluminum or its alloys for reasons of weight. Since aluminum and aluminum alloys coat themselves with a corrosion-protecting oxide layer, it is not necessary to provide such surfaces with a coating for corrosion protection reasons. Therefore, the bodies of rail vehicles made of these materials are often unpainted. Rail vehicles, however, are often used as advertising media, with plastic films affixed to their surfaces being used for advertising purposes. After a certain period of use, these plastic films must be removed and, if necessary, replaced with new plastic films. The plastic films are mechanically removed as far as possible. However, it cannot be avoided here that adhesive residues and / or film residues remain on the surfaces. Before applying new foils, these residues must be removed by cleaning. A suitable cleaning process serves both to remove film or adhesive residues from the surfaces and to prepare these surfaces so that new plastic films can be stuck on in a durable manner. 2
  • alkali metal hydroxide solution in particular sodium hydroxide solution
  • the alkali lye reacts with the aluminum oxides of the surface to form soluble aluminates. This removes the top surface layer and creates a new bare aluminum surface that automatically coats with aluminum oxides.
  • film and adhesive residues soften under the action of the alkali metal hydroxide solution, so that they can be rinsed off with water after a certain exposure time, which can be, for example, of the order of 15 minutes.
  • organic polymeric substances such as celluloses are used as thickeners.
  • these have the disadvantage that the alkali metal solution thickened with this is not fully stable in storage. Rather, phase separation and / or
  • the object of the invention is to provide a method for cleaning surfaces of aluminum or aluminum alloys using a thickened alkali metal hydroxide solution, the thickener not leading to the disadvantages mentioned above.
  • This object is achieved by a process for cleaning surfaces of aluminum or aluminum alloys, wherein a thickened alkali hydroxide solution is applied to the surfaces and rinsed off after a predetermined exposure time, characterized in that the alkali hydroxide solution a) 2 to 42% by weight alkali metal hydroxide, b ) 2 to 15% by weight of swellable layered silicate, c) if desired, further auxiliaries or active substances and d) the remainder containing 100% by weight of water.
  • sodium hydroxide is preferably used as the alkali metal hydroxide.
  • Potassium hydroxide is equally technically suitable.
  • the procedure is preferably such that the water is initially introduced and the swellable layered silicate is stirred in to produce a thixotropic paste. Dispersing machines (so-called inline mixers), for example, are suitable as stirring units for this. Alternatively, high-speed mixers with multi-blade stirrers can be used. After the layered silicate has been homogeneously mixed and led to optimum swelling, the desired amount of alkali metal hydroxide is stirred in, for example in the form of a 50% strength by weight sodium hydroxide solution.
  • the viscosity of the thickened alkali metal hydroxide solution is of the order of 200 to 1500, preferably 500 to 1000 mPas.
  • Swellable layered silicates are known in the prior art. These are usually substances that contain layers of silicon and aluminum ions bridged by oxygen atoms. Because tetravalent silicon is partially replaced by trivalent aluminum in the layers, the entire layers are negatively charged. The charge balance in the layer silicates, which are neutral to the outside, takes place in that between the layers 4
  • Metal cations are stored. If monovalent cations such as lithium, sodium and / or potassium ions are stored as metal cations between the silicate layers, the bond between the layers is so small that water can penetrate between the layers, so that the silicate layers move away from one another. This process is called swelling. The swelling process can proceed so far in water that the individual silicate layers are completely detached from one another. This state is recognizable from the fact that such an aqueous suspension of swollen layered silicates has a significantly higher viscosity than water. Such suspensions of swollen sheet silicates often show the property of thixotropy. That is, their viscosity depends on the shear rate and falls with increasing shear rate.
  • hectorite, bentonite and montmorillonite are suitable as swellable layered silicates, with montmorillonite being preferred for reasons of cost.
  • the alkali metal lye thickened with swellable layered silicate can, if desired, contain further active ingredients or auxiliaries such as, for example, surface-active substances, colorants and / or odorous substances in amounts of up to a total of about 10% by weight.
  • active substances or auxiliary substances are generally not required to solve the cleaning task. Therefore, for reasons of cost, it is preferred that the thickened alkali hydroxide solution contains no further auxiliaries or active ingredients.
  • the thickened alkali solution is applied to the surfaces. This can be done, for example, by brushing or brushing, but preferably by spraying. Because of its viscosity and its preferably present thixotropy, the thickened alkali metal solution adheres to the surfaces long enough that plastic films and 5
  • the use of swellable layered silicates has the advantage that they do not lead to an increased C SB value in the waste water.
  • the layered silicates In contrast to the known organic thickeners, which have a water hazard class of 1 to 2 according to German law, the layered silicates have a water hazard class of 0. With their use, stable and constant viscosity alkali lye can be produced, which means that the application to the surfaces takes place under constant conditions can.
  • Layered silicates have another advantage over organic thickeners: by heating the aluminum surface, aluminum ions accumulate in the alkali metal hydroxide solution. As soon as they have reached a certain threshold concentration, they react with the layer silicates in such a way that they lose their swelling capacity. The effect may be due to the fact that the trivalent aluminum ions firmly bind the individual silicate layers to one another, so that they lose their ability to swell. In the course of the cleaning process according to the invention, this leads to the viscosity of the alkali metal solution being significantly reduced when the aluminum surfaces have been sufficiently stained. The alkali lye previously adhering to the surfaces then begins to drain off by itself. After that, only slight residues of lye have to be rinsed off the surfaces, which saves time and rinsing water.
  • concentrations of alkali metal hydroxide and swellable layered silicate are preferably chosen so that the exposure time on the aluminum surfaces before the described reduction in viscosity and thus 6 is in the range of about 5 to about 20 minutes before the alkali lye runs off independently.
  • the cleaning process is usually carried out at ambient temperature, preferably in the temperature range between about 5 and about 35 ° C.
  • the aim of the cleaning method according to the invention is to remove adhesives and / or plastic films from the surfaces of aluminum or aluminum alloys.
  • the surfaces are prepared by the pickling effect so that they can be glued with new plastic films after cleaning and drying without further pretreatment.
  • a cleaning agent which can be used for the process according to the invention can contain, for example, 15% by weight sodium hydroxide, 10% by weight montmorillonite and the remainder up to 100% by weight water.
  • the components are preferably mixed in the order given above.
  • the viscosity of this agent measured according to Brookfield at 25 ° C. with spindle No. 5 at 100 revolutions per minute, is in the range of approximately 800 mPas.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
  • Detergent Compositions (AREA)

Abstract

The invention relates to a method for cleaning aluminium or aluminium alloy surfaces. A thickened lye is applied to the surfaces and after a predetermined cleaning time, is washed off. The invention is characterised in that the lye contains a) 2 to 42 wt. % alkaline metal oxide, b) 2 to 15 wt. % sheet silicate capable of swelling, c) optionally, other auxiliary or active agents and d) water constituting the remainder of the 100 wt. %.

Description

"Verfahren zur Reinigung von Aluminiumoberflächen" "Process for cleaning aluminum surfaces"
Die Erfindung betrifft ein Verfahren zur Reinigung von Oberflächen von Aluminium oder Aluminiumlegierungen. Dabei werden unter Aluminiumlegierungen solche Legierungen verstanden, die zu mindestens 90 Gew.- % aus Aluminium bestehen. Insbesondere ist das Verfahren konzipiert zur Reinigung von Schienenfahrzeugen, die Oberflächen aus Aluminium oder Aluminiumlegierungen aufweisen.The invention relates to a method for cleaning surfaces of aluminum or aluminum alloys. Aluminum alloys are understood to mean those alloys which consist of at least 90% by weight of aluminum. In particular, the method is designed for cleaning rail vehicles that have surfaces made of aluminum or aluminum alloys.
Die Aufbauten von Schienenfahrzeugen bestehen aus Gewichtsgründen häufig aus Aluminium oder seinen Legierungen. Da sich Aluminium und Aluminiumlegierungen von selbst mit einer korrosionsschützenden Oxidschicht überziehen, ist es nicht erforderlich, derartige Oberflächen aus Korrosionsschutzgründen mit einem Lacküberzug zu versehen. Daher sind die Aufbauten von Schienenfahrzeugen aus diesen Materialien häufig unlackiert. Schienenfahrzeuge werden jedoch häufig als Werbeträger verwendet, wobei auf ihre Oberflächen werbewirksam gestaltete Kunststoffolien aufgeklebt werden. Nach einer bestimmten Gebrauchsdauer müssen diese Kunststoffolien entfernt und ggf. durch neue Kunststoffolien ersetzt werden. Dabei werden die Kunststoffolien so weit wie möglich mechanisch abgezogen. Hierbei läßt es sich jedoch nicht vermeiden, daß Klebstoffreste und/oder Folienreste auf den Oberflächen verbleiben. Vor dem Bekleben mit neuen Folien müssen diese Reste durch eine Reinigung entfernt werden. Dabei dient ein geeignetes Reinigungsverfahren sowohl dazu, Folien- oder Klebstoffreste von den Oberflächen zu entfernen als auch diese Oberflächen so vorzubereiten, daß neue Kunststoffolien haltbar aufgeklebt werden können. 2The structures of rail vehicles often consist of aluminum or its alloys for reasons of weight. Since aluminum and aluminum alloys coat themselves with a corrosion-protecting oxide layer, it is not necessary to provide such surfaces with a coating for corrosion protection reasons. Therefore, the bodies of rail vehicles made of these materials are often unpainted. Rail vehicles, however, are often used as advertising media, with plastic films affixed to their surfaces being used for advertising purposes. After a certain period of use, these plastic films must be removed and, if necessary, replaced with new plastic films. The plastic films are mechanically removed as far as possible. However, it cannot be avoided here that adhesive residues and / or film residues remain on the surfaces. Before applying new foils, these residues must be removed by cleaning. A suitable cleaning process serves both to remove film or adhesive residues from the surfaces and to prepare these surfaces so that new plastic films can be stuck on in a durable manner. 2
Für diese Aufgabe der Reinigung und der Vorbereitung der Oberflächen ist es bekannt, Alkalilauge wie insbesondere Natronlauge auf die Oberflächen einwirken zu lassen. Die Alkalilauge reagiert mit den Aluminiumoxiden der Oberfläche zu löslichen Aluminaten. Die oberste Oberflächenschicht wird hierdurch entfernt und eine neue blanke Aluminiumoberfläche erzeugt, die sich von selbst wieder mit Aluminiumoxiden überzieht. Außerdem erweichen unter der Einwirkung der Alkalilauge Folien- und Klebstoffreste, so daß sie nach einer bestimmten Einwirkungszeit, die beispielsweise in der Größenordnung von 15 Minuten liegen kann, mit Wasser abgespült werden können.For this task of cleaning and preparing the surfaces, it is known to allow alkali metal hydroxide solution, in particular sodium hydroxide solution, to act on the surfaces. The alkali lye reacts with the aluminum oxides of the surface to form soluble aluminates. This removes the top surface layer and creates a new bare aluminum surface that automatically coats with aluminum oxides. In addition, film and adhesive residues soften under the action of the alkali metal hydroxide solution, so that they can be rinsed off with water after a certain exposure time, which can be, for example, of the order of 15 minutes.
Um auf schrägen oder senkrechten Oberflächen eine ausreichende Einwirkungszeit der Alkalilauge zu gewährleisten, ist es bekannt, die Viskosität der Alkalilauge durch ein Verdickungsmittel zu erhöhen. Die Alkalilauge läuft dann nur langsam oder überhaupt nicht von den zu reinigenden Oberflächen ab.In order to ensure a sufficient exposure time of the alkali metal hydroxide solution on inclined or vertical surfaces, it is known to increase the viscosity of the alkali metal hydroxide solution by means of a thickener. The alkali solution then runs off slowly or not at all from the surfaces to be cleaned.
Als Verdickungsmittel werden im Stand der Technik organische polymere Substanzen wie beispielsweise Cellulosen eingesetzt. Diese weisen zum einen den Nachteil auf, daß die hiermit verdickte Alkalilauge nicht uneingeschränkt lagerstabil ist. Vielmehr können Phasentrennung und/oderIn the prior art, organic polymeric substances such as celluloses are used as thickeners. On the one hand, these have the disadvantage that the alkali metal solution thickened with this is not fully stable in storage. Rather, phase separation and / or
Viskositätsschwankungen auftreten, die die Anwendung erschweren. Zum zweiten haben die organischen Verdickungsmittel den Nachteil, daß sie das Abwasser mit chemischem Sauerstoffbedarf (CSB) belasten und damit die Abwasserbehandlung verteuern und erschweren.Viscosity fluctuations occur that make application difficult. Second, the organic thickeners have the disadvantage that they pollute the wastewater with chemical oxygen demand (COD) and thus make wastewater treatment more expensive and more difficult.
Die Erfindung stellt sich die Aufgabe, ein Verfahren zur Reinigung von Oberflächen von Aluminium oder Aluminiumlegierungen unter Verwendung einer verdickten Alkalilauge zur Verfügung zu stellen, wobei das Verdickungsmittel nicht zu den vorstehend genannten Nachteilen führt. 3The object of the invention is to provide a method for cleaning surfaces of aluminum or aluminum alloys using a thickened alkali metal hydroxide solution, the thickener not leading to the disadvantages mentioned above. 3
Diese Aufgabe wird gelöst durch ein Verfahren zur Reinigung von Oberflächen von Aluminium oder Aluminiumlegierungen, wobei man eine verdickte Alkalilauge auf die Oberflächen aufträgt und nach einer vorgegebenen Einwirkungszeit abspült, dadurch gekennzeichnet, daß die Alkalilauge a) 2 bis 42 Gew.-% Alkalimetallhydroxid, b) 2 bis 15 Gew.-% quellfähiges Schichtsilicat, c) erwünschtenfalls weitere Hilfs- oder Wirkstoffe und d) als Rest zu 100 Gew.-% Wasser enthält.This object is achieved by a process for cleaning surfaces of aluminum or aluminum alloys, wherein a thickened alkali hydroxide solution is applied to the surfaces and rinsed off after a predetermined exposure time, characterized in that the alkali hydroxide solution a) 2 to 42% by weight alkali metal hydroxide, b ) 2 to 15% by weight of swellable layered silicate, c) if desired, further auxiliaries or active substances and d) the remainder containing 100% by weight of water.
Aus Kostengründen setzt man als Alkalimetallhydroxid vorzugsweise Natriumhydroxid ein. Kaliumhydroxid ist technisch jedoch gleichermaßen geeignet. Dabei geht man vorzugsweise so vor, daß man das Wasser vorlegt und das quellfähige Schichtsilicat zur Herstellung einer thixotropen Paste einrührt. Als Rühraggregate hierfür sind beispielsweise Dispergiermaschinen (sogenannte Inlinemischer) geeignet. Alternativ kommen hochtourige Mischer mit mehrflügeligen Rührern in Frage. Nachdem das Schichtsilicat homogen vermischt und zu einer optimalen Quellung geführt ist, wird die erwünschte Menge Alkalimetallhydroxid beispielsweise in -Form einer 50 gew-%igen Natronlauge eingerührt. Dabei verwendet man vorzugsweise so viel quellfähiges Schichtsilicat und so viel Natronlauge, daß die Viskosität der verdickten Alkalilauge, gemessen bei 25 °C nach Brookfield mit Spindel 5 bei 100 Umdrehungen pro Minute in der Größenordnung 200 bis 1500, vorzugsweise bei 500 bis 1000 mPas liegt.For reasons of cost, sodium hydroxide is preferably used as the alkali metal hydroxide. Potassium hydroxide is equally technically suitable. The procedure is preferably such that the water is initially introduced and the swellable layered silicate is stirred in to produce a thixotropic paste. Dispersing machines (so-called inline mixers), for example, are suitable as stirring units for this. Alternatively, high-speed mixers with multi-blade stirrers can be used. After the layered silicate has been homogeneously mixed and led to optimum swelling, the desired amount of alkali metal hydroxide is stirred in, for example in the form of a 50% strength by weight sodium hydroxide solution. It is preferable to use so much swellable layered silicate and so much sodium hydroxide solution that the viscosity of the thickened alkali metal hydroxide solution, measured at 25 ° C. according to Brookfield with spindle 5 at 100 revolutions per minute, is of the order of 200 to 1500, preferably 500 to 1000 mPas.
Quellfähige Schichtsilicate sind im Stand der Technik bekannt. Hierbei handelt es sich in der Regel um Substanzen, die Schichten aus über Sauerstoffatome verbrückten Silicium- und Aluminiumionen enthalten. Dadurch, daß in den Schichten teilweise vierwertiges Silicium durch dreiwertiges Aluminium ersetzt ist, sind die gesamten Schichten negativ geladen. Der Ladungsausgleich in den nach außen neutralen Schichtsilicaten erfolgt dadurch, daß zwischen den Schichten 4Swellable layered silicates are known in the prior art. These are usually substances that contain layers of silicon and aluminum ions bridged by oxygen atoms. Because tetravalent silicon is partially replaced by trivalent aluminum in the layers, the entire layers are negatively charged. The charge balance in the layer silicates, which are neutral to the outside, takes place in that between the layers 4
Metallkationen eingelagert werden. Sind als Metallkationen einwertige Kationen wie beispielsweise Lithium-, Natrium- und/oder Kaliumionen zwischen den Silicatschichten eingelagert, ist die Bindung zwischen den Schichten so gering, daß Wasser zwischen die Schichten eindringen kann, so daß sich die Silicatschichten voneinander entfernen. Dieser Vorgang wird als Quellung bezeichnet. Der Quellprozeß kann in Wasser so weit fortschreiten, daß die einzelnen Silicatschichten völlig voneinander gelöst vorliegen. Dieser Zustand ist dadurch erkennbar, daß eine derartige wäßrige Suspension von gequollenen Schichtsilicaten eine deutlich höhere Viskosität als Wasser aufweist. Häufig zeigen solche Suspensionen gequollener Schichtsilicate die Eigenschaft der Thixotropie. D.h., ihre Viskosität hängt von der Schergeschwindigkeit ab und fällt mit steigender Schergeschwindigkeit.Metal cations are stored. If monovalent cations such as lithium, sodium and / or potassium ions are stored as metal cations between the silicate layers, the bond between the layers is so small that water can penetrate between the layers, so that the silicate layers move away from one another. This process is called swelling. The swelling process can proceed so far in water that the individual silicate layers are completely detached from one another. This state is recognizable from the fact that such an aqueous suspension of swollen layered silicates has a significantly higher viscosity than water. Such suspensions of swollen sheet silicates often show the property of thixotropy. That is, their viscosity depends on the shear rate and falls with increasing shear rate.
Als quellfähige Schichtsilicate sind beispielsweise Hectorit, Bentonit und Montmorillonit geeignet, wobei aus Kostengründen Montmorillonit bevorzugt wird.For example, hectorite, bentonite and montmorillonite are suitable as swellable layered silicates, with montmorillonite being preferred for reasons of cost.
Die mit quellfähigem Schichtsilicat verdickte Alkalimetallauge kann erwünschtenfalls weitere Wirk- oder Hilfsstoffe wie beispielsweise oberflächenaktive Stoffe, Färb- und/oder Geruchsstoffe in Mengen bis zu insgesamt etwa 10 Gew.-% enthalten. Zur Lösung der gestellten Reinigungsaufgabe sind derartige Wirk- oder Hilfsstoffe jedoch in der Regel nicht erforderlich. Daher ist es aus Kostengründen bevorzugt, daß die verdickte Alkalilauge keine weiteren Hilfsoder Wirkstoffe enthält.The alkali metal lye thickened with swellable layered silicate can, if desired, contain further active ingredients or auxiliaries such as, for example, surface-active substances, colorants and / or odorous substances in amounts of up to a total of about 10% by weight. However, such active substances or auxiliary substances are generally not required to solve the cleaning task. Therefore, for reasons of cost, it is preferred that the thickened alkali hydroxide solution contains no further auxiliaries or active ingredients.
Zur Reinigung der mit Folien- und/oder Klebstoffresten verunreinigten Oberflächen von Aluminium oder Aluminiumlegierungen wird die verdickte Alkalilauge auf die Oberflächen aufgetragen. Dies kann beispielsweise durch Aufstreichen mit Bürsten oder Pinseln, vorzugsweise jedoch durch Besprühen erfolgen. Aufgrund ihrer Viskosität und ihrer vorzugsweise vorhandenen Thixotropie haftet die verdickte Alkalimetallauge lange genug an den Oberflächen, daß Kunststoffolien und 5To clean the surfaces of aluminum or aluminum alloys contaminated with film and / or adhesive residues, the thickened alkali solution is applied to the surfaces. This can be done, for example, by brushing or brushing, but preferably by spraying. Because of its viscosity and its preferably present thixotropy, the thickened alkali metal solution adheres to the surfaces long enough that plastic films and 5
Klebstoffreste erweichen und abgespült werden können. Gleichzeitig wird die Aluminiumoberfläche durch Ablösen der obersten Oxidschicht angebeizt und hierdurch für das Aufkleben neuer Kunststoffolien vorbereitet.Soften adhesive residue and can be rinsed off. At the same time, the aluminum surface is stained by removing the top oxide layer, thereby preparing it for sticking on new plastic films.
Gegenüber den bekannten organischen Verdickungsmitteln hat die Verwendung von quellfähigen Schichtsilicaten zum einen den Vorteil, daß diese nicht zu einem erhöhten C SB- Wert des Abwassers fuhren. Im Gegensatz zu den bekannten organischen Verdickungsmitteln, die nach deutschem Recht eine Wassergefährdungsklasse von 1 bis 2 aufweisen, haben die Schichtsilicate eine Wassergefahrdungsklasse von 0. Mit ihrer Verwendung lassen sich stabile und viskositätskonstante verdickte Alkalilaugen herstellen, wodurch der Auftrag auf die Oberflächen unter konstanten Bedingungen erfolgen kann.Compared to the known organic thickeners, the use of swellable layered silicates has the advantage that they do not lead to an increased C SB value in the waste water. In contrast to the known organic thickeners, which have a water hazard class of 1 to 2 according to German law, the layered silicates have a water hazard class of 0. With their use, stable and constant viscosity alkali lye can be produced, which means that the application to the surfaces takes place under constant conditions can.
Gegenüber den organischen Verdickungsmitteln haben die Schichtsilicate einen weiteren Vorteil: Durch das Anheizen der Aluminiumoberfläche reichern sich Aluminiumionen in der Alkalilauge an. Sobald diese eine bestimmte Schwellkonzentration erreicht haben, reagieren sie mit den Schichtsilicaten in der Art, daß diese ihre Quellfähigkeit verlieren. Der Effekt dürfte darauf beruhen, daß die dreiwertigen Aluminiumionen die einzelnen Silicatschichten fest aneinander binden, so daß diese ihre Quellfähigkeit verlieren. Im Zuge des erfindungsgemäßen Reinigungsverfahrens führt dies dazu, daß sich die Viskosität der Alkalilauge deutlich verringert, wenn die Aluminiumoberflächen ausreichend angebeizt worden sind. Die vorher an den Oberflächen haftende Alkalilauge beginnt dann von den Oberflächen von selbst abzulaufen. Danach müssen nur noch geringfügige Laugenreste von den Oberflächen abgespült werden, was zu einer Ersparnis von Zeit und von Spülwasser führt.Layered silicates have another advantage over organic thickeners: by heating the aluminum surface, aluminum ions accumulate in the alkali metal hydroxide solution. As soon as they have reached a certain threshold concentration, they react with the layer silicates in such a way that they lose their swelling capacity. The effect may be due to the fact that the trivalent aluminum ions firmly bind the individual silicate layers to one another, so that they lose their ability to swell. In the course of the cleaning process according to the invention, this leads to the viscosity of the alkali metal solution being significantly reduced when the aluminum surfaces have been sufficiently stained. The alkali lye previously adhering to the surfaces then begins to drain off by itself. After that, only slight residues of lye have to be rinsed off the surfaces, which saves time and rinsing water.
Die Konzentrationen von Alkalimetallhydroxid und quellfähigem Schichtsilicat werden vorzugsweise so gewählt, daß die Einwirkungszeit auf den Aluminiumoberflächen vor der beschriebenen Viskositätsverminderung und damit 6 vor dem selbständigen Ablaufen der Alkalilauge im Bereich von etwa 5 bis etwa 20 Minuten liegt. Den Reinigungsprozeß führt man in der Regel bei Umgebungstemperatur, vorzugsweise im Temperaturbereich zwischen etwa 5 und etwa 35 °C durch.The concentrations of alkali metal hydroxide and swellable layered silicate are preferably chosen so that the exposure time on the aluminum surfaces before the described reduction in viscosity and thus 6 is in the range of about 5 to about 20 minutes before the alkali lye runs off independently. The cleaning process is usually carried out at ambient temperature, preferably in the temperature range between about 5 and about 35 ° C.
Gemäß der eingangs geschilderten Aufgabenstellung besteht das Ziel des erfindungsgemäßen Reinigungsverfahrens darin, von den Oberflächen von Aluminium oder Aluminiumlegierungen Klebstoffe und/oder Plastikfolien zu entfernen. Gleichzeitig werden hierbei die Oberflächen durch den Beizeffekt so vorbereitet, daß sie nach der Reinigung und Trocknung ohne weitere Vorbehandlung mit neuen Kunststoffolien beklebt werden können.According to the task described in the introduction, the aim of the cleaning method according to the invention is to remove adhesives and / or plastic films from the surfaces of aluminum or aluminum alloys. At the same time, the surfaces are prepared by the pickling effect so that they can be glued with new plastic films after cleaning and drying without further pretreatment.
Ein für das erfindungsgemäße Verfahren einsetzbares Reinigungsmittel kann beispielsweise 15 Gew.-% Natriumhydroxid, 10 Gew.-% Montmorillonit und als Rest zu 100 Gew.-% Wasser enthalten. Hierbei vermischt man die Komponenten vorzugsweise in der weiter oben angegebenen Reihenfolge. Die Viskosität dieses Mittels, gemessen nach Brookfield bei 25 °C mit Spindel Nr. 5 bei 100 Umdrehungen pro Minute liegt im Bereich von etwa 800 mPas. A cleaning agent which can be used for the process according to the invention can contain, for example, 15% by weight sodium hydroxide, 10% by weight montmorillonite and the remainder up to 100% by weight water. The components are preferably mixed in the order given above. The viscosity of this agent, measured according to Brookfield at 25 ° C. with spindle No. 5 at 100 revolutions per minute, is in the range of approximately 800 mPas.

Claims

7Patentansprüche 7Patent claims
1. Verfahren zur Reinigung von Oberflächen von Aluminium oder Aluminiumlegierungen, wobei man eine verdickte Alkalilauge auf die Oberflächen aufträgt und nach einer vorgegebenen Einwirkungszeit abspült, dadurch gekennzeichnet, daß die Alkalilauge1. A method for cleaning surfaces of aluminum or aluminum alloys, wherein a thickened alkali metal solution is applied to the surfaces and rinsed off after a predetermined exposure time, characterized in that the alkali metal hydroxide solution
a) 2 bis 42 Gew.-% Alkalimetallhydroxid, b) 2 bis 15 Gew.-% quellfähiges Schichtsilicat, c) erwünschtenfalls weitere Hilfs- oder Wirkstoffe und d) als Rest zu 100 Gew.-% Wassera) 2 to 42% by weight of alkali metal hydroxide, b) 2 to 15% by weight of swellable layered silicate, c) if desired, further auxiliaries or active ingredients and d) the remainder to 100% by weight of water
enthält.contains.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß als Alkalimetallhydroxid Natriumhydroxid verwendet wird.2. The method according to claim 1, characterized in that sodium hydroxide is used as the alkali metal hydroxide.
3. Verfahren nach einem oder beiden der Ansprüche 1 und 2, dadurch gekennzeichnet, daß das quellfähige Schichtsilicat ausgewählt ist aus Hectorit, Bentonit und Montmorillonit.3. The method according to one or both of claims 1 and 2, characterized in that the swellable layered silicate is selected from hectorite, bentonite and montmorillonite.
4. Verfahren nach einem oder mehreren der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß die verdickte Alkalilauge keine weiteren Hilfs- oder Wirkstoffe c) enthält.4. The method according to one or more of claims 1 to 3, characterized in that the thickened alkali metal solution contains no further auxiliaries or active ingredients c).
5. Verfahren nach einem oder mehreren der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß die Einwirkungszeit im Bereich von 5 bis 20 Minuten liegt.5. The method according to one or more of claims 1 to 4, characterized in that the exposure time is in the range of 5 to 20 minutes.
6. Verfahren nach einem oder mehreren der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß bei der Reinigung der Oberflächen von Aluminium oder 86. The method according to one or more of claims 1 to 5, characterized in that when cleaning the surfaces of aluminum or 8th
Aluminiumlegierungen Klebstoffe und/oder Plastikfolien von den Oberflächen entfernt werden.Aluminum alloy adhesives and / or plastic films can be removed from the surfaces.
7. Verfahren nach einem oder mehreren der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß die Oberflächen von Aluminium oder Aluminiumlegierungen nach der Reinigung mit Kunsstoff-Folien beklebt werden. 7. The method according to one or more of claims 1 to 6, characterized in that the surfaces of aluminum or aluminum alloys are glued with plastic films after cleaning.
PCT/EP1999/001662 1998-03-23 1999-03-13 Method for cleaning aluminium surfaces WO1999049104A1 (en)

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DE1998112622 DE19812622A1 (en) 1998-03-23 1998-03-23 Process for cleaning aluminum surfaces
DE19812622.0 1998-03-23

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DE102004004140A1 (en) * 2004-01-28 2005-08-18 Henkel Kgaa Pickling process and pickling product for aluminum

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB669281A (en) * 1946-06-27 1952-04-02 Ciba Ltd Method of cleansing undyed materials contaminated with heavy metal oxides or water-insoluble heavy metal salts, and manufacture of preparations therefor
US3779933A (en) * 1965-12-28 1973-12-18 Glamorene Products Corp Alkaline oven cleaning composition
US4135947A (en) * 1977-04-22 1979-01-23 Union Carbide Corporation Method of cleaning surfaces with CO2 -neutralized amine compositions
EP0130678A2 (en) * 1983-07-05 1985-01-09 Ecolab Inc. Highly alkaline liquid warewashing emulsion stabilized by clay thickener
US4502891A (en) * 1981-02-12 1985-03-05 Sterling Drug Inc. Dry powder compositions for preparing paint strippers
US4652393A (en) * 1983-09-02 1987-03-24 Research Chemical Coating remover and wood restorative compositions and methods of using same

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB669281A (en) * 1946-06-27 1952-04-02 Ciba Ltd Method of cleansing undyed materials contaminated with heavy metal oxides or water-insoluble heavy metal salts, and manufacture of preparations therefor
US3779933A (en) * 1965-12-28 1973-12-18 Glamorene Products Corp Alkaline oven cleaning composition
US4135947A (en) * 1977-04-22 1979-01-23 Union Carbide Corporation Method of cleaning surfaces with CO2 -neutralized amine compositions
US4502891A (en) * 1981-02-12 1985-03-05 Sterling Drug Inc. Dry powder compositions for preparing paint strippers
EP0130678A2 (en) * 1983-07-05 1985-01-09 Ecolab Inc. Highly alkaline liquid warewashing emulsion stabilized by clay thickener
US4652393A (en) * 1983-09-02 1987-03-24 Research Chemical Coating remover and wood restorative compositions and methods of using same

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