EP0244685A1 - Aqueous acid galvanic bath - Google Patents
Aqueous acid galvanic bath Download PDFInfo
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- EP0244685A1 EP0244685A1 EP87105754A EP87105754A EP0244685A1 EP 0244685 A1 EP0244685 A1 EP 0244685A1 EP 87105754 A EP87105754 A EP 87105754A EP 87105754 A EP87105754 A EP 87105754A EP 0244685 A1 EP0244685 A1 EP 0244685A1
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D3/00—Electroplating: Baths therefor
- C25D3/02—Electroplating: Baths therefor from solutions
- C25D3/22—Electroplating: Baths therefor from solutions of zinc
Definitions
- auxiliaries are, for example, conductive salts, which are used to improve the conductivity of the baths, and so-called brighteners, which give the zinc coatings on the metals an increased sheen.
- the brighteners also make it possible to work at low current densities.
- the brighteners which can be assigned to a wide variety of chemical substance classes, are often poorly or not at all soluble in water and especially in salt solutions, so that another group of auxiliaries, namely surfactants, is required to fine-tune the brighteners in the electroplating bath Bring distribution.
- the surfactants act as emulsifiers for the brighteners and produce clear, transparent microemulsions from which a uniform deposition of the zinc on the substrates is made possible.
- nonionic surfactants have hitherto been used as surfactants in galvanic zinc baths, cf. GB-PS 1 149 106. From US Pat. No. 3,787,296 it is also known to use sulfated alkylphenol alkoxylates as surfactants in galvanic zinc baths. The gloss and ductility of the deposited zinc layers are not always optimal when using these compounds.
- EP-A-115 020 discloses the use of sulfated alkylphenol ethoxylates, the phenol nucleus of which still carries a sulfonic acid group, as a surfactant in aqueous acidic galvanic zinc baths. These surfactants are able to solubilize the other water-poorly soluble auxiliaries, such as brighteners, and produce high-gloss, uniform and ductile coatings. However, these surfactants are not optimally effective in ammonium salt-free baths, which are sought among other things for reasons of environmental compatibility.
- the present invention has for its object to provide surfactants for aqueous acidic electroplating baths for the electrolytic deposition of zinc, in particular ammonium salt-free zinc baths, from which zinc coatings with improved properties, in particular gloss and ductility, are deposited on metals compared to the known acidic zinc baths can be.
- the substituent R 2 in formula I is preferably hydrogen.
- the compounds of the formula I are preferably used as surfactants in aqueous, acidic, ammonium salt-free galvanic baths for the electrolytic deposition of zinc in the presence of brighteners.
- the compounds of the formula I are known and differ from the surfactants which, according to EP-A-115 020, are used in aqueous acidic galvanic baths for the electrolytic deposition of zinc in the presence of brighteners, by the partial or complete replacement of ethylene oxide units by propylene oxide and / or butylene oxide units. At least one ethylene oxide unit of the surfactants according to the EP application mentioned is replaced by a propylene oxide or butylene oxide unit.
- the substituent R1 is a C4- to C20- Alkyl group.
- Suitable Me are hydrogen, alkali metal or equivalents of an alkaline earth metal or zinc atom, preferably sodium and potassium.
- the substituent R in formula I preferably has the meaning CH3-.
- the alkoxylation of the phenol derivatives can also be carried out using a mixed gas of ethylene oxide and propylene oxide and, if appropriate, butylene oxide.
- the compounds of formula I are obtained from the alkoxylated phenol derivatives by esterifying the alkoxylated products with sulfuric acid and optionally neutralizing them.
- the compounds of the formula I must be water-soluble.
- the surfactants of the formula I to be used according to the invention are present in the baths in an amount of 1 to 30, preferably 2 to 15 g / l.
- the compounds of the formula I can optionally be used in a mixture with known surfactants which are usually used in electroplating baths, for example compounds such as p-C4H9- to C12H25- Alkylphenol ethoxylates with 10 to 30 ethylene oxide units or ⁇ -naphthol ethoxylates with 5 to 20 ethylene oxide units.
- the additional surfactants that are considered, if they are used, are used in an amount of 1 to 15 g / l of the bath.
- the zinc baths usually contain brighteners.
- the brighteners used can be divided into so-called basic brighteners and top brighteners.
- Polyethyleneimines or their derivatives, for example, are expedient as basic gloss agents.
- the top brighteners are usually poorly or not at all soluble in the aqueous zinc bath. These include representatives of the most diverse classes of substances, in particular certain aromatic or heteroaromatic ketones, as are described, for example, in GB-PS 1 149 106 or JP-OS 74 89 637.
- R3 is an aromatic or heteroaromatic radical, preferably an optionally alkyl, halogen or nitro-substituted phenyl or thienyl radical and R4 is C1 to C6 alkyl, or crude products containing these compounds.
- This class of compounds includes representatives such as:
- benzal acetone is preferred.
- o-chlorobenzaldehyde can be used alone or as a mixture with a compound of the formula II as a brightener.
- the zinc baths advantageously contain brighteners in a total amount of 1 to 10 g / l and the top brighteners in an amount of 0.1 to 2.0 g / l, preferably 0.1 to 1 g / l.
- the baths have the usual compositions. They contain, for example, 50 to 150 g / l zinc chloride or the equivalent amount of zinc sulfate, 100 to 250 g / l potassium chloride (conductive salt), 15 to 25 g / l Boric acid, 1 to 8 g / l sodium benzoate and optionally 1 to 4 g / l of an agent to increase the scatter, for example naphthalenesulfonic acid-formaldehyde condensation products. 10 to 150 g / l ammonium chloride or sodium chloride can also be used as conductive salts.
- the pH of the baths is usually 3 to 6. The pH is adjusted by adding acids to the bath, eg sulfuric acid or hydrochloric acid.
- metals mainly iron and steel, are galvanized in order to protect them against corrosion and at the same time to give them a high gloss.
- the compounds of the formula I are used as surfactants in aqueous, acidic, ammonium salt-free galvanic baths for the electrodeposition of zinc.
- the baths according to the invention provide high-gloss and ductile zinc coatings with an improved quality compared to the prior art over the entire range of current density that is technically possible.
- Bath 1 is an ammonium salt-free bath according to the preferred embodiment of the invention, while bath 2 is an ammonium salt-containing bath.
- bath 1 The pH of bath 1 is 4.8, bath 2 has a pH of 4.5.
- the pH is adjusted with dilute hydrochloric acid.
- the galvanizing of steel sheets for testing purposes takes place over 10 minutes by galvanizing in a Hull cell with 1 ampere at approx. 23 ° C.
- the quality of the zinc coatings obtained and the composition of the surfactants contained in the baths are given in the following table.
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- Electroplating And Plating Baths Therefor (AREA)
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Abstract
Description
Bei der elektrolytischen Abscheidung von Zink auf metallische Substrate aus wäßriger saurer Lösung benötigt man verschiedene Hilfsmittel, weil andernfalls die aus saurer Lösung entstehenden Zinküberzüge meistens matt und häufig auch unregelmäßig anfallen. Eine Gruppe solcher Hilfsmittel sind beispielsweise Leitsalze, die zur Verbesserung der Leitfähigkeit der Bäder eingesetzt werden sowie sogenannte Glanzbildner, die den Zinküberzügen auf den Metallen einen erhöhten Glanz verleihen. Die Glanzbildner erlauben es auch, bei geringen Stromdichten zu arbeiten. Die Glanzbildner, die den verschiedensten chemischen Stoffklassen zugeordnet werden können, sind häufig in Wasser und vor allem in Salzlösungen schwer oder überhaupt nicht löslich, so daß man eine weitere Gruppe von Hilfsmitteln, nämlich Tenside, benötigt, um die Glanzbildner im galvanischen Bad in eine feine Verteilung zu bringen. Die Tenside wirken als Emulgatoren für die Glanzbildner und ergeben klare, durchsichtige Mikroemulsionen, aus denen eine gleichmäßige Abscheidung des Zinks auf den Substraten ermöglicht wird.Various means are required for the electrolytic deposition of zinc on metallic substrates from aqueous acidic solution, because otherwise the zinc coatings resulting from acidic solution are usually matt and often also irregular. A group of such auxiliaries are, for example, conductive salts, which are used to improve the conductivity of the baths, and so-called brighteners, which give the zinc coatings on the metals an increased sheen. The brighteners also make it possible to work at low current densities. The brighteners, which can be assigned to a wide variety of chemical substance classes, are often poorly or not at all soluble in water and especially in salt solutions, so that another group of auxiliaries, namely surfactants, is required to fine-tune the brighteners in the electroplating bath Bring distribution. The surfactants act as emulsifiers for the brighteners and produce clear, transparent microemulsions from which a uniform deposition of the zinc on the substrates is made possible.
Als Tenside in galvanischen Zinkbädern sind bisher eine Reihe von nichtionischen Tensiden eingesetzt worden, vgl. GB-PS 1 149 106. Aus der US-PS 3 787 296 ist außerdem bekannt, sulfatierte Alkylphenolalkoxylate als Tenside in galvanischen Zinkbädern zu verwenden. Glanz und Duktilität der abgeschiedenen Zinkschichten sind bei Einsatz dieser Verbindungen nicht immer optimal.A number of nonionic surfactants have hitherto been used as surfactants in galvanic zinc baths, cf. GB-PS 1 149 106. From US Pat. No. 3,787,296 it is also known to use sulfated alkylphenol alkoxylates as surfactants in galvanic zinc baths. The gloss and ductility of the deposited zinc layers are not always optimal when using these compounds.
Aus der EP-A-115 020 ist die Verwendung von sulfatierten Alkylphenolethoxylaten, deren Phenolkern noch eine Sulfonsäuregruppe trägt, als Tensid in wäßrigen sauren galvanischen Zinkbädern bekannt. Diese Tenside vermögen die in Wasser schwer löslichen übrigen Hilfsmittel, wie Glanzbildner, gut zu solubilisieren und ergeben hochglänzende, gleichmäßige und duktile Überzüge. Diese Tenside sind jedoch in Ammoniumsalz-freien Bädern, die unter anderem aus Gründen der Umweltverträglichkeit angestrebt werden, nicht optimal wirksam.EP-A-115 020 discloses the use of sulfated alkylphenol ethoxylates, the phenol nucleus of which still carries a sulfonic acid group, as a surfactant in aqueous acidic galvanic zinc baths. These surfactants are able to solubilize the other water-poorly soluble auxiliaries, such as brighteners, and produce high-gloss, uniform and ductile coatings. However, these surfactants are not optimally effective in ammonium salt-free baths, which are sought among other things for reasons of environmental compatibility.
Der vorliegenden Erfindung liegt die Aufgabe zugrunde, Tenside für wäßrige saure galvanische Bäder zur elektrolytischen Abscheidung von Zink zur Verfügung zu stellen, insbesondere Ammoniumsalz-freie Zinkbäder, aus denen gegenüber den bekannten sauren Zinkbädern Zinküberzüge mit verbesserten Eigenschaften, insbesondere Glanz und Duktilität, auf Metallen abgeschieden werden können.The present invention has for its object to provide surfactants for aqueous acidic electroplating baths for the electrolytic deposition of zinc, in particular ammonium salt-free zinc baths, from which zinc coatings with improved properties, in particular gloss and ductility, are deposited on metals compared to the known acidic zinc baths can be.
Die Aufgabe wird erfindungsgemäß gelöst durch ein wäßriges saures galvanisches Bad zur elektrolytischen Abscheidung von Zink, wobei das Bad als wesentliche Hilfsmittel Leitsalze, Glanzbildner und Tenside enthält, wenn das Bad Tenside einer Verbindung der Formel
R = CH₃-, CH₃-CH₂-
x,z = 0 bis 49,
y = 1 bis 25,
x+y+z = 3 bis 50,
R¹ = C₄- bis C₂₀-Alkyl,
R² = H, C₄- bis C₂₀-Alkyl und
Me = H, Alkalimetallatom oder ein Äquivalent eines Erdalkalimetall- oder Zinkatoms
bedeuten. Vorzugsweise steht der Substituent R² in Formel I für Wasserstoff.The object is achieved according to the invention by an aqueous acidic galvanic bath for the electrolytic deposition of zinc, the bath containing conductive salts, brightening agents and surfactants as essential auxiliaries if the bath contains surfactants of a compound of the formula
R = CH₃-, CH₃-CH₂-
x, z = 0 to 49,
y = 1 to 25,
x + y + z = 3 to 50,
R¹ = C₄ to C₂₀ alkyl,
R² = H, C₄ to C₂₀ alkyl and
Me = H, alkali metal atom or an equivalent of an alkaline earth metal or zinc atom
mean. The substituent R 2 in formula I is preferably hydrogen.
Die Verbindungen der Formel I werden vorzugsweise als Tensid in wäßrigen, sauren, Ammoniumsalz-freien galvanischen Bädern zur elektrolytischen Abscheidung von Zink in Gegenwart von Glanzbildnern verwendet. Die Verbindungen der Formel I sind bekannt und unterscheiden sich von den Tensiden, die gemäß der EP-A-115 020 in wäßrigen sauren galvanischen Bädern zur elektrolytischen Abscheidung von Zink in Gegenwart von Glanzbildnern eingesetzt werden, durch den partiellen oder vollständigen Ersatz von Ethylenoxid-Einheiten durch Propylenoxid- und/oder Butylenoxid-Einheiten. Mindestens eine Ethylenoxid-Einheit der Tenside gemäß der genannten EP-Anmeldung ist durch eine Propylenoxid- oder Butylenoxid-Einheit ersetzt. In den Verbindungen der oben angegebenen Formel I bedeutet der Substituent R² vorzugsweise Wasserstoff, die Zahl der gesamten Alkylenoxid-Einheiten, d.h. die Summe aus x+y+z = 3 bis 50, vorzugsweise 6 bis 25, y steht für Zahlen von 1 bis 25, vorzugsweise 3 bis 15, x und z können Werte von 0 bis 49 annehmen. Der Substituent R¹ ist eine C₄- bis C₂₀- Alkylgruppe. Als Me kommen Wasserstoff, Alkalimetall oder Äquivalente eines Erdalkalimetalls oder Zinkatoms in Betracht, vorzugsweise Natrium und Kalium. Der Substituent R in Formel I hat vorzugsweise die Bedeutung CH₃-.The compounds of the formula I are preferably used as surfactants in aqueous, acidic, ammonium salt-free galvanic baths for the electrolytic deposition of zinc in the presence of brighteners. The compounds of the formula I are known and differ from the surfactants which, according to EP-A-115 020, are used in aqueous acidic galvanic baths for the electrolytic deposition of zinc in the presence of brighteners, by the partial or complete replacement of ethylene oxide units by propylene oxide and / or butylene oxide units. At least one ethylene oxide unit of the surfactants according to the EP application mentioned is replaced by a propylene oxide or butylene oxide unit. In the compounds of the formula I given above, the substituent R 2 preferably denotes hydrogen, the number of the total alkylene oxide units, ie the sum of x + y + z = 3 to 50, preferably 6 to 25, y represents numbers from 1 to 25 , preferably 3 to 15, x and z can assume values from 0 to 49. The substituent R¹ is a C₄- to C₂₀- Alkyl group. Suitable Me are hydrogen, alkali metal or equivalents of an alkaline earth metal or zinc atom, preferably sodium and potassium. The substituent R in formula I preferably has the meaning CH₃-.
Verbindungen der Formel I werden beispielsweise dadurch erhalten, daß man das zugrundeliegende Phenol mit Ethylenoxid zur Reaktion bringt, wobei an 1 Mol Phenol x Mol Ethylenoxid angelagert werden. Dieses Reaktionsprodukt wird danach mit Propylenoxid und/oder Butylenoxid umgesetzt. Pro Mol Phenol lagert man y Mol Propylenoxid oder Butylenoxid oder eine Mischung aus Propylenoxid und Butylenoxid an das Additionsprodukt an. An dieses Additionsprodukt kann noch weiteres Ethylenoxid angelagert werden. Bezogen auf 1 Mol des eingesetzten Phenols kommen in diesem Fall z Mol Ethylenoxid. Die Bedeutung von x, y und z ist oben angegeben. Für den Fall, daß z gleich 0 bedeutet, liegen alkoxylierte Phenolderivate vor, bei denen die Alkoxylierung zunächst mit Ethylenoxid und anschließend mit Propylenoxid vorgenommen wurde. Für den Fall, daß x gleich 0 bedeutet, wurde die Alkoxylierung der den Verbindungen der Formel I zugrundeliegenden Phenole zunächst mit Propylenoxid und/oder Butylenoxid und anschließend mit Ethylenoxid vorgenommen, wobei in diesem Fall z mindestens 1 ist. Besonders wirksame Tenside für den Einsatz in wäßrigen sauren galvanischen Bädern zur elektrolytischen Abscheidung von Zink erhält man, wenn man die den Verbindungen der Formel I zugrundeliegenden Phenolderivate 3 bis 15 Mol Propylenoxid und 3 bis 15 Mol Ethylenoxid pro Mol Phenol umsetzt. Das Phenolderivat kann dabei entweder zuerst mit Ethylenoxid und anschließend mit Propylenoxid zur Reaktion gebracht werden. In diesem Fall ist in Formel I x = 3 bis 15 und y = 3 bis 15. Das Phenolderivat kann aber auch zunächst mit Propylenoxid und danach mit Ethylenoxid in den vorstehend angegebenen bevorzugten Molverhältnissen umgesetzt werden. Dann bedeuten in Formel I y und z = 3 bis 15 und x = 0. Die Alkoxylierung der Phenolderivate kann auch mit einem Mischgas aus Ethylenoxid und Propylenoxid sowie gegebenenfalls Butylenoxid vorgenommen werden. Die Verbindungen der Formel I werden aus den alkoxylierten Phenolderivaten erhalten, indem man die alkoxylierten Produkte mit Schwefelsäure verestert und gegebenenfalls neutralisiert. Die Verbindungen der Formel I müssen wasserlöslich sein. Sie können allein oder in Mischung verwendet werden. Die erfindungsgemäß zu verwendenden Tenside der Formel I sind in den Bädern in einer Menge von 1 bis 30, vorzugsweise 2 bis 15 g/l enthalten. Die Verbindungen der Formel I können gegebenenfalls in Mischung mit bekannten, üblicherweise in galvanischen Bädern verwendeten Tensiden eingesetzt werden, z.B. Verbindungen wie p-C₄H₉- bis C₁₂H₂₅- Alkylphenolethoxylaten mit 10 bis 30 Ethylenoxid-Einheiten oder β-Naphtholethoxylaten mit 5 bis 20 Ethylenoxid-Einheiten. Die zusätzlich in Betracht kommenden Tenside werden, sofern sie mitverwendet werden, in einer Menge von 1 bis 15 g/l des Bades eingesetzt.Compounds of the formula I are obtained, for example, by reacting the underlying phenol with ethylene oxide, with 1 mol of phenol x mole of ethylene oxide being added. This reaction product is then reacted with propylene oxide and / or butylene oxide. Per mole of phenol, y moles of propylene oxide or butylene oxide or a mixture of propylene oxide and butylene oxide are added to the addition product. Further ethylene oxide can also be added to this addition product. In this case, based on 1 mole of the phenol used, there are z moles of ethylene oxide. The meaning of x, y and z is given above. In the event that z is 0, there are alkoxylated phenol derivatives in which the alkoxylation was carried out first with ethylene oxide and then with propylene oxide. In the event that x is 0, the alkoxylation of the phenols on which the compounds of the formula I are based was first carried out with propylene oxide and / or butylene oxide and then with ethylene oxide, in which case z is at least 1. Particularly effective surfactants for use in aqueous acidic galvanic baths for the electrodeposition of zinc are obtained if the phenol derivatives on which the compounds of the formula I are based are reacted with 3 to 15 moles of propylene oxide and 3 to 15 moles of ethylene oxide per mole of phenol. The phenol derivative can either be reacted first with ethylene oxide and then with propylene oxide. In this case, in formula I x = 3 to 15 and y = 3 to 15. However, the phenol derivative can also be reacted first with propylene oxide and then with ethylene oxide in the preferred molar ratios given above. Then in formula I, y and z = 3 to 15 and x = 0. The alkoxylation of the phenol derivatives can also be carried out using a mixed gas of ethylene oxide and propylene oxide and, if appropriate, butylene oxide. The compounds of formula I are obtained from the alkoxylated phenol derivatives by esterifying the alkoxylated products with sulfuric acid and optionally neutralizing them. The compounds of the formula I must be water-soluble. They can be used alone or in a mixture. The surfactants of the formula I to be used according to the invention are present in the baths in an amount of 1 to 30, preferably 2 to 15 g / l. The compounds of the formula I can optionally be used in a mixture with known surfactants which are usually used in electroplating baths, for example compounds such as p-C₄H₉- to C₁₂H₂₅- Alkylphenol ethoxylates with 10 to 30 ethylene oxide units or β-naphthol ethoxylates with 5 to 20 ethylene oxide units. The additional surfactants that are considered, if they are used, are used in an amount of 1 to 15 g / l of the bath.
Die Zinkbäder enthalten üblicherweise Glanzbildner. Die verwendeten Glanzbildner können eingeteilt werden in sog. Grundglanzbildner und Spitzenglanzbildner. Als Grundglanzbildner sind zweckmäßig beispielsweise Polyethylenimine oder deren Derivate. Die Spitzenglanzbildner sind in der Regel im wäßrigen Zinkbad schlecht oder überhaupt nicht löslich. Hierzu gehören Vertreter der verschiedensten Stoffklassen, insbesondere bestimmte aromatische oder heteroaromatische Ketone, wie sie beispielsweise in der GB-PS 1 149 106 oder der JP-OS 74 89 637 beschrieben sind.The zinc baths usually contain brighteners. The brighteners used can be divided into so-called basic brighteners and top brighteners. Polyethyleneimines or their derivatives, for example, are expedient as basic gloss agents. The top brighteners are usually poorly or not at all soluble in the aqueous zinc bath. These include representatives of the most diverse classes of substances, in particular certain aromatic or heteroaromatic ketones, as are described, for example, in GB-PS 1 149 106 or JP-OS 74 89 637.
Es sind dies zum Beispiel die Verbindungen der Formel II
Diese Verbindungsklasse umfaßt Vertreter wie:
Davon ist das Benzalaceton bevorzugt. Darüber hinaus kann als Glanzbildner o-Chlorbenzaldehyd allein oder in Mischung mit einer Verbindung der Formel II verwendet werden.Of these, benzal acetone is preferred. In addition, o-chlorobenzaldehyde can be used alone or as a mixture with a compound of the formula II as a brightener.
Die Zinkbäder enthalten Glanzbildner zweckmäßig in einer Gesamtmenge von 1 bis 10 g/l und die Spitzenglanzbildner in einer Menge von 0,1 bis 2,0 g/l, vorzugsweise 0,1 bis 1 g/l.The zinc baths advantageously contain brighteners in a total amount of 1 to 10 g / l and the top brighteners in an amount of 0.1 to 2.0 g / l, preferably 0.1 to 1 g / l.
Im übrigen weisen die Bäder die üblichen Zusammensetzungen auf. Sie enthalten beispielsweise 50 bis 150 g/l Zinkchlorid oder die äquivalente Menge Zinksulfat, 100 bis 250 g/l Kaliumchlorid (Leitsalz), 15 bis 25 g/l Borsäure, 1 bis 8 g/l Natriumbenzoat und gegebenenfalls 1 bis 4 g/l eines Agens zur Erhöhung der Streuung, z.B. Naphthalinsulfonsäure-Formaldehyd-Kondensationsprodukte. Als Leitsalze können auch 10 bis 150 g/l Ammoniumchlorid oder Natriumchlorid verwendet werden. Der pH-Wert der Bäder liegt in der Regel bei 3 bis 6. Die Einstellung des pH-Wertes erfolgt durch Zugabe von Säuren zum Bad, z.B. Schwefelsäure oder Salzsäure.Otherwise, the baths have the usual compositions. They contain, for example, 50 to 150 g / l zinc chloride or the equivalent amount of zinc sulfate, 100 to 250 g / l potassium chloride (conductive salt), 15 to 25 g / l Boric acid, 1 to 8 g / l sodium benzoate and optionally 1 to 4 g / l of an agent to increase the scatter, for example naphthalenesulfonic acid-formaldehyde condensation products. 10 to 150 g / l ammonium chloride or sodium chloride can also be used as conductive salts. The pH of the baths is usually 3 to 6. The pH is adjusted by adding acids to the bath, eg sulfuric acid or hydrochloric acid.
In den beschriebenen Bädern werden Metalle, hauptsächlich Eisen und Stahl galvanisiert, um sie gegen Korrosion zu schützen und ihnen gleichzeitig einen hohen Glanz zu verleihen.In the baths described, metals, mainly iron and steel, are galvanized in order to protect them against corrosion and at the same time to give them a high gloss.
Besonders vorteilhafte Ergebnisse werden erhalten, wenn man die Verbindungen der Formel I als Tensid in wäßrigen, sauren, Ammoniumsalz-freien galvanischen Bädern zur elektrolytischen Abscheidung von Zink verwendet. Die erfindungsgemäßen Bäder liefern über den gesamten technisch in Betracht kommenden Stromdichtenbereich hochglänzende und duktile Zinküberzüge mit einer gegenüber dem Stand der Technik verbesserten Qualität.Particularly advantageous results are obtained if the compounds of the formula I are used as surfactants in aqueous, acidic, ammonium salt-free galvanic baths for the electrodeposition of zinc. The baths according to the invention provide high-gloss and ductile zinc coatings with an improved quality compared to the prior art over the entire range of current density that is technically possible.
Die Wirksamkeit von Tensiden der Formel I in galvanischen Bädern zur elektrolytischen Abscheidung von Zink in Gegenwart von Glanzbildnern wird anhand von zwei verschiedenen Bädern demonstriert. Bad 1 ist ein Ammoniumsalz-freies Bad gemäß der bevorzugten Ausführungsform der Erfindung während das Bad 2 ein Ammoniumsalz-haltiges Bad ist.
Der pH-Wert des Bads 1 beträgt 4,8, das Bad 2 hat einen pH-Wert von 4,5. Die Einstellung des pH-Wertes erfolgt jeweils mit verdünnter Salzsäure. Die Verzinkung von Stahlblechen zu Prüfzwecken erfolgt während 10 Minuten, indem man in einer Hull-Zelle mit 1 Ampere bei ca. 23°C galvanisiert. Die Qualität der dabei erhaltenen Zinküberzüge sowie die Zusammensetzung der jeweils in den Bädern enthaltenen Tenside ist in der folgenden Tabelle angegeben.
Claims (5)
R = CH₃-, CH₃-CH₂-
x, z = 0 bis 49,
y = 1 bis 25,
x+y+z = 3 bis 50
R¹ = C₄- bis C₂₀-Alkyl,
R² = H, C₄- bis C₂₀-Alkyl und
Me = H, Alkalimetallatom oder ein Äquivalent eines Erdalkali metall- oder Zinkatoms
bedeuten.1. Aqueous acidic galvanic bath for the electrolytic deposition of zinc, the bath containing conductive salts, brightening agents and surfactants as essential auxiliaries, characterized in that the bath contains surfactants of a compound of the formula
R = CH₃-, CH₃-CH₂-
x, z = 0 to 49,
y = 1 to 25,
x + y + z = 3 to 50
R¹ = C₄ to C₂₀ alkyl,
R² = H, C₄ to C₂₀ alkyl and
Me = H, alkali metal atom or an equivalent of an alkaline earth metal or zinc atom
mean.
R = CH₃-, CH₃-CH₂-
x,z = 0 bis 49,
y = 1 bis 25,
x+y+z = 3 bis 50,
R¹ = C₄- bis C₂₀-Alkyl,
R² = H, C₄- bis C₂₀-Alkyl und
Me = H, Alkalimetallatom oder ein Äquivalent eines Erdalkalimetall- oder Zinkatoms
bedeuten, als Tensid in wäßrigen, sauren, ammoniumsalzfreien galvanischen Bädern zur elektrolytischen Abscheidung von Zink in Gegenwart von Glanzbildnern.5. Use of compounds of the formula
R = CH₃-, CH₃-CH₂-
x, z = 0 to 49,
y = 1 to 25,
x + y + z = 3 to 50,
R¹ = C₄ to C₂₀ alkyl,
R² = H, C₄ to C₂₀ alkyl and
Me = H, alkali metal atom or an equivalent of an alkaline earth metal or zinc atom
mean, as a surfactant in aqueous, acidic, ammonium salt-free galvanic baths for the electrolytic deposition of zinc in the presence of brighteners.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19863613874 DE3613874A1 (en) | 1986-04-24 | 1986-04-24 | AQUEOUS ACID GALVANIC BATH |
| DE3613874 | 1986-04-24 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0244685A1 true EP0244685A1 (en) | 1987-11-11 |
| EP0244685B1 EP0244685B1 (en) | 1989-07-26 |
Family
ID=6299436
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP87105754A Expired EP0244685B1 (en) | 1986-04-24 | 1987-04-18 | Aqueous acid galvanic bath |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0244685B1 (en) |
| DE (2) | DE3613874A1 (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4270990A (en) * | 1979-06-07 | 1981-06-02 | Minnesota Mining And Manufacturing Company | Acidic electroplating baths with novel surfactants |
| EP0115020A2 (en) * | 1982-12-29 | 1984-08-08 | BASF Aktiengesellschaft | Acid galvanic zinc bath |
-
1986
- 1986-04-24 DE DE19863613874 patent/DE3613874A1/en not_active Withdrawn
-
1987
- 1987-04-18 DE DE8787105754T patent/DE3760367D1/en not_active Expired
- 1987-04-18 EP EP87105754A patent/EP0244685B1/en not_active Expired
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4270990A (en) * | 1979-06-07 | 1981-06-02 | Minnesota Mining And Manufacturing Company | Acidic electroplating baths with novel surfactants |
| EP0115020A2 (en) * | 1982-12-29 | 1984-08-08 | BASF Aktiengesellschaft | Acid galvanic zinc bath |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3613874A1 (en) | 1987-10-29 |
| DE3760367D1 (en) | 1989-08-31 |
| EP0244685B1 (en) | 1989-07-26 |
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