EP0134895B1 - Process and compounds for applying accelerated and grain-refined phosphate coatings to metallic surfaces - Google Patents

Abstract

Phosphate conversion coating accelerators consisting essentially of amidosulfonic acid, N-substitution products and salts thereof, sulfonamides, 1,2,3-oxathiazin-4(3H)-one salts or 6-alkyl derivatives thereof, and ortho-aniline sulfonic acid or its derivatives aklyl-substituted on the ring and salts thereof, and mixtures of the foregoing, and a process for their use.

Description

in der

• R¹ für Wasserstoff, einen linearen oder verzweigten Alkylrest mit 1 bis 4 C-Atomen, einen fünf- oder sechsgliedrigen gesättigten carbocyclischen oder heterocyclischen Rest oder einen mindestens sechsgliedrigen Aryl- oder Aralkylrest und
• R² für eine Hydroxygruppe, eine Gruppe der Zusammensetzung -0-M⁺, in der M⁺ ein Alkalimetall- oder ein Ammoniumion bedeutet, oder einen mindestens sechsgliedrigen aromatischen, gegebenenfalls mit einer Hydroxy- oder Aminogruppe substituierten Ring stehen, mit der Maßgabe, daß wenn R¹ Wasserstoff bedeutet, R² nicht für eine OH- oder 0-M^+-Gruppe stehen darf ;
  
  in der R³ für Wasserstoff, eine Hydroxy- oder Aminogruppe steht, und/oder Alkalimetall- und Ammoniumsalze von Verbindungen dieser Formel ;
  
  in der R⁴ für Wasserstoff oder einen linearen oder verzweigten Alkylrest mit 1 bis 4 C-Atomen steht und M⁺ die obengenannte Bedeutung hat ; als beschleunigende und schichtverfeinernde Komponente, in einer Menge von 0,1 bis 6g/l, in Phosphatierlösungen auf der Basis von Zinkphosphat und/oder Eisenphosphat und/oder Zinkeisenphosphat, die zum Aufbringen von Phosphatüberzügen auf Metalloberflächen dienen, neben anderen, in solchen Phosphatierlösungen üblicherweise verwendeten Komponenten.

The invention relates to the use of one or more compounds of the general formulas (I), (II) or (III)

in the

• R ^{1 is} hydrogen, a linear or branched alkyl radical having 1 to 4 carbon atoms, a five- or six-membered saturated carbocyclic or heterocyclic radical or an at least six-membered aryl or aralkyl radical and
• R ^{2 represents} a hydroxyl group, a group of the composition -0-M ⁺ , in which M ^{+ represents} an alkali metal or an ammonium ion, or an at least six-membered aromatic ring which is optionally substituted by a hydroxyl or amino group, with the proviso that when R ^{1 is} hydrogen, R ^{2 must} not represent an OH or 0-M ⁺ group;
  
  in which R ^{3 represents} hydrogen, a hydroxyl or amino group, and / or alkali metal and ammonium salts of compounds of this formula;
  
  in which R ^{4 represents} hydrogen or a linear or branched alkyl radical having 1 to 4 carbon atoms and M ^{+ has} the abovementioned meaning; as an accelerating and layer-refining component, in an amount of 0.1 to 6 g / l, in phosphating solutions based on zinc phosphate and / or iron phosphate and / or zinc iron phosphate, which are used to apply phosphate coatings on metal surfaces, among others, usually in such phosphating solutions components used.

It has long been known to produce iron phosphate layers on iron and steel surfaces. Alkali and / or ammonium orthophosphate solutions with a pH value of 3.0 to 6.5 are used (so-called “non-layer-forming phosphating”).

Furthermore, processes are known with the help of which zinc phosphate layers are formed on metal surfaces (so-called “layer-forming phosphating”). Such layers improve corrosion protection and paint adhesion. Older processes required high reaction temperatures and a considerable treatment time for the layer formation. The process of layer formation can be shortened by adding accelerators. Oxidizing agents such as nitrate, nitrite, chlorate, hydrogen peroxide and organic nitro compounds play an important role as accelerators.

For example, DE-A-30 16576 describes a method for accelerating the formation of phosphate layers based on zinc phosphate, the application solution containing nitrite and chlorate as accelerators. A method based on a solution of zinc phosphate uses a combination of chlorate and a water-soluble aromatic nitro compound, preferably Na-m-nitrobenzenesulfonate (DE-A-32 24 923) as accelerator. A comparable combination is claimed in GB-A-15 42 222.

DE-A-30 04 927 also describes a method for forming phosphate layers on metal surfaces with the aid of zinc phosphate solutions which contain nitrite and / or organic nitro compounds and, if appropriate, additionally chlorate.

The use of water soluble aromatic nitro compounds in accelerator systems for In the course of the reaction with the metal surface, the phosphating process also leads to severe discoloration of the phosphating solutions and to the formation of voluminous sludge.

Both disadvantages complicate the conduct of the procedure and make permanent “re-sharpening”, ie. H. Readjustment of the contents of the solutions required.

US-A-3 923 554 relates to a method for producing phosphate layers on iron surfaces with the aid of aqueous zinc phosphate solutions which contain nitrite ions. In order to eliminate the undesirable inhibiting effects of the nitrite ions on the layer formation, 0.1 to 10 g / l, based on the total solution, of urea or urea nitrate are added to these solutions. The same effect can also be achieved by adding sulfamic acid, alkali metal or ammonium salts of sulfamic acid, ascorbic acid, hydroxylamine or hydroxylamine derivatives to such solutions. The appearance and the corrosion resistance of the layers are not impaired by the additives mentioned, but rather improved. As the examples show, with such phosphating solutions - with treatment times of several hours and treatment temperatures between 90 and 95 ° C - comparatively thick phosphate coatings result.

Furthermore, the subject of NL-C-102 953 is a phosphating process in which phosphating solutions are used which, in addition to chlorate and / or nitrate or nitrite or halogenate, are also a compound of the general formula RS0 ₂ NHCI, in which R is an aralkyl radical with at most 5 carbon atoms in the alkyl chain, contained as accelerators. In addition to such compounds, their salts, such as in particular chloramine-T, can also be used.

In such phosphating baths, a large number of factors influence, for example the temperature of the phosphating solution, the oxygen supply, the reactivity of the metal surfaces to be treated, the mechanical movement of the phosphating solution, the spray pressure and the pH, the effect of nitrite on the formation of the phosphate layer. From this it can be seen that the bath management in the presence of nitrite depends on a large number of complex, related factors.

It should also be borne in mind that phosphating solutions often contain nitrate. Carrying out the phosphating process at elevated temperature in the presence of nitrates increasingly leads to an autoreduction of the nitrate with the formation of additional nitrite. The formation of these amounts of nitrite is difficult to control and is undesirable since - as mentioned above - there is an increasing passivation of the metal surfaces.

A particular disadvantage is that the use of nitrite-containing systems to accelerate phosphating solutions leads to the release of nitrous gases. This disadvantage makes it seem advisable to completely dispense with the use of nitrite and possibly nitrate as a phosphating accelerator or to choose reaction conditions under which nitrite does not form.

The adjustment and maintenance of the pH value is of great importance for the formation of a good phosphate layer. The pH can be between 1.8 and 5.8. It is preferably adjusted to the desired value using phosphoric acid.

However, the use of sulfamic acid is also described for this purpose. The subject of DE-A-21 52 446 - or the parallel FR-A-21 10784 and BE-A-767 775 - is, for example, a process for phosphating metal surfaces with the aid of aqueous solutions which contain acidic non-layer-forming phosphates. In this case, sulfamic acid is used as the acidic component for adjusting or maintaining the pH in amounts of 0.5 to 10% by weight, preferably 3 to 6% by weight, based on the content of acidic non-layer-forming phosphate in the solution. In addition, such solutions contain oxidizing accelerators, such as nitrates, nitrites, chlorates or molybdates.

Further disadvantages of the above-mentioned processes are that the obtainable basis weights of the phosphate layer are difficult to control and the phosphate layers obtained are not sufficiently fine-grained for good paint adhesion. Furthermore, the methods mentioned lack the ability to set certain layer weights and grain sizes by changing simple parameters and to control the formation of phosphate layers depending on the temperature.

For corrosion protection and as a lubricant carrier in cold forming, thick and fully developed phosphate coatings with coating weights of 10 to 35 g / m ^{2 are} desirable. Such high contact weights are normally achieved at phosphating bath temperatures of 70 to 100 ° C. DE-A-22 41 798 describes such a nitrate-accelerated immersion process in which the weight ratio of P ₂ 0 ₅ : Zn: N0 ₃ is 1: (0.7 to 2.0): (0.3 to 0.7) must be set. DE-C-15 21f927 also claims a nitrate-accelerated process in which the weight ratio P ₂ O ₅ : Zn: N0 ₃ should be 1: (1.4 to 2.6): (2.0 to 4.3) . Common to both processes is a small addition of sodium nitrite, which is necessary for starting the phosphating solution, which is only added when the bath is prepared. The further formation of nitrite required for the formation of a phosphate coating on the metal surface takes place autocatalytically from nitrate. As a result, there is a risk that the ferrous iron entering the bath during the throughput of iron and steel will be oxidized to an appreciable extent to iron (111) and this will lead to precipitation and undesirable sludge formation.

In cold forming practice, soaps in combination with phosphate layers are used as lubricants. The zinc phosphate layers on the workpiece can partially do so with alkali soaps be implemented so that the particularly effective zinc soap is formed. The tertiary zinc phosphate of the layer reacts with sodium soap to form zinc soap and tertiary sodium phosphate. For the implementation, the phosphated workpieces are immersed in a soaping bath at 70 to 80 ° C. for 2 to 10 minutes. The greatest possible conversion and thus the best forming results are obtained with special reactive soap lubricants, the immersion baths used with 2 to 10% by weight of which have a pH between 8 and 1-0.

The formation of the phosphate layers can be influenced by special pre-rinses. With such pre-rinses, it is often possible to exaggerate the effects of previous treatments, e.g. B. an alkaline degreasing or pickling. Such pre-rinses are therefore widely used in practice.

Zinc phosphating processes based on the so-called low zinc technology are also used. This is a process variant that differs from normal zinc technology in some essential points. These variants concern in particular the concentrations in which the determining bath components zinc and phosphate are present in the treatment solution and the weight and molar ratios of these two components to one another. While the weight ratio of zinc to phosphate is about 1: (1 to 12) in the normal zinc phosphating baths, with which metal surfaces are treated for subsequent painting, it is 1: (14 to 30) in the low zinc phosphating baths.

In DE-A-22 32 067 it is pointed out that especially the low zinc technology leads to phosphate coatings on metal, which are superior to the normal zinc processes in terms of paint adhesion and corrosion protection. However, the low-zinc phosphating technology has procedural disadvantages, especially with regard to the management of the phosphating baths. The phosphating rate is lower with the low zinc phosphating process; the throughputs are accordingly lower. The bath components in the phosphating bath are used in a ratio to each other that differs significantly from that in which they are present in the bath itself. Therefore, according to EP-A-0 064 790, phosphating concentrates with very different compositions are required for the bath preparation and for the bath supplement. Furthermore, the monitoring of the phosphating baths is relatively complex, especially since the ratio of chemical consumption to mechanical discharge, which in turn u. a. depends on the shape of the metal piece being treated, on the draining options and on the type of phosphating system, is not a constant.

The object of the present invention is to provide a method for accelerated and layer-improving application of phosphate coatings on metal surfaces which does not have the aforementioned disadvantages. In particular, a process should be made available that does not require nitrite as an accelerator component and also leads to the same results in terms of paint adhesion and corrosion protection in normal zinc technology that can be achieved with low zinc technology. In addition, simplifying the monitoring of the contents of the individual accelerator components was intended to simplify bath management and reduce the amount of sludge in the phosphating baths. The new process should also be based on the use of environmentally friendly and toxicologically safe compounds.

It has now been found that this object can be achieved if, as the accelerating and layer-refining component, N-substitution products of amidosulfonic acid (also called sulfamic acid) and their salts (general formula 1), sulfonamides (general formula I), benzenesulfanilides (general formula) , Benzoesäuresulfimide (general formula) and 1,2.3-oxathiazin-4 (3H) -one salts and their 6-alkyl derivatives (general formula 111) used individually or in combination with one another in addition to other components commonly used in phosphating solutions.

The invention accordingly relates to the use of one or more compounds of the general formulas (I), (II) and (111) defined above as accelerating and layer-refining components, in an amount of 0.1 to 6 g / l, in phosphating solutions on the Basis of zinc phosphate and / or iron phosphate and / or zinc iron phosphate, which are used to apply phosphate coatings on metal surfaces, in addition to other components that are commonly used in such phosphating solutions.

In preferred embodiments, the compounds of the general formulas (I), (11) and (III) according to the invention are used in combination with m-nitrobenzenesulfonic acid as a co-accelerator. This leads to an effective acceleration of the phosphating process.

In addition to the substances according to the invention, nitrate and - in the presence of compounds of the general formulas (III) - nitrite can also be used as co-accelerators. However, it is considered advantageous for the purposes of the present invention to dispense with the addition of nitrite as an accelerator component when using the compounds according to the invention.

In preferred embodiments of the invention, one or more compounds from the group N-cyclohexanesulfamic acid and its salts, benzenesulfanilide, benzoic acid sulfimide, 1,2.3-oxathiazin-4 (3H) -one potassium and its 6-methyl derivative are used as accelerating and layer-refining components used. Other sulfonamides are also suitable, in particular those whose aromatic radical carries further polar radicals which improve the water solubility of the compounds, such as, for. B. hydroxy or amino residues or amido residues of dicarboxylic acids.

The water solubility of the compounds according to the invention should be so good. that at least Dissolve 2 g of the compounds of the general formulas (I), (11) and / or (111) in one liter of phosphating solution. This is generally given by the fact that water-soluble salts, preferably alkali metal salts of the N-substituted derivatives of amidosulfonic acid, and / or further compounds are selected which carry polar groups which improve water solubility as substituents.

The active constituents of the phosphating solution can be introduced into water in the form of water-soluble or acid-soluble salts or compounds or as acids in a manner known per se. Are suitable for. B. sodium dihydrogen phosphate, ammonium dihydrogen phosphate, zinc nitrate, zinc oxide, zinc carbonate, acid zinc phosphate, nickel carbonate, iron nitrate, alkali chlorate and phosphoric acid. The presence of chlorate is not absolutely necessary for the formation of phosphate layers. Rather, phosphate layers with high coating weights are formed by the process accelerated according to the invention in the presence and in the absence of chlorate. In the absence of chlorate, small additions of molybdate can also be used.

Optimal phosphate layer formation for subsequent coating with paints and other organic coatings with regard to paint adhesion and corrosion is obtained if chlorate is used as a further accelerator component in accordance with a preferred embodiment of the present invention and the ratio of the compounds of the general formulas (I), ( 11) and / or (111) for C10 ₃ to a value in the range from (0.1 to 10): 1. In the case of the presence of molybdate as a further accelerator component in the phosphating solution, a further preferred embodiment of the invention leads to optimal phosphate layer formation if the ratio of the compounds of the general formulas (I), (11) and / or (111) according to the invention to Mo0 ₄ is set to a value in the range of (10 to 100): 1.

The process accelerated according to the invention is particularly suitable for producing phosphate coatings on steel, galvanized steel, aluminum or on surfaces which contain several of these metals. It is advantageously used to produce phosphate layers which are suitable both as a corrosion protection layer and layer for improving paint adhesion and as a sliding layer for cold forming.

If necessary, the phosphating solutions used to produce phosphate layers on metal surfaces can have further constituents. It is advantageous to use solutions for the phosphating of aluminum surfaces which additionally contain 0.1 to 5.0 g / l of fluoride, which can be present in the phosphating solution as free or complex-bound fluoride ion. Suitable complex fluorides are e.g. B. fluoroborates and / or fluorosilicates.

Phosphating solutions which additionally contain Ni, Co and / or Fe ions can advantageously be used for the layer formation on galvanized steel. However, these ions should not be present in a total amount above 3.0 g / l. Salts of these metals are advantageously used in a concentration of 0.1 to 4.5 g / l as salts of the aforementioned simple or complex fluorides. Phosphating solutions containing nickel, cobalt and / or iron and fluoride are particularly well suited for the formation of layers on surfaces consisting of several metals. However, the total amount of nickel, cobalt and / or iron ions must not be greater than the amount of zinc ions.

For the purposes of the invention, it is also advantageous to use phosphating solutions which additionally contain a total of 0.3 to 5.0 g / l of a mixture of nonionic surfactants.

The effectiveness of sulfamic acid derivatives is impaired in phosphating solutions that contain calcium ions. Accelerators which do not form poorly soluble calcium salts, for example benzoic acid sulfimide or benzene sulfanilides, are therefore used in such phosphating solutions according to the invention.

The pH of the phosphating solution with which the metal surfaces intended for subsequent painting are brought into contact should be between 1.8 and 5.8, preferably between 2.0 and 3.5. The free acid and the total acid can be determined by potentiometric titration or by titration against phenolphthalein (total acid) and bromocresol green (free acid) with aqueous 0.1 N sodium hydroxide solution and are between 5 and 30 (total acid) and 0.1-2 , 5 (free acid) points (= ml 0.1 N NaOH).

The process accelerated according to the invention has the advantage of delivering well-formed phosphate coatings of up to 30 g / m ² on metal surfaces with a total acidity of less than 40 points and with a free acidity of 20 points, which are then subjected to cold forming.

The metal surfaces can be treated in any manner to form homogeneous phosphate layers. Diving and spraying systems and combined diving / spraying systems are particularly suitable.

The treatment times for spraying are between 20 and 300, preferably between 30 and 180 seconds. In the immersion process, well-formed phosphate layers of up to 22 g / m ² were formed after only 300 seconds. The treatment times depend on the process conditions (temperature of the phosphating solution, pH value, spray pressure), the nature of the metal surfaces to be phosphated and the upstream treatment of the metals to be phosphated.

The temperatures at which the metal surfaces can be brought into contact with phosphating solutions using the accelerators according to the invention in the phosphating agents are from 25 to 70 ° C., for the formation of phosphate layers with high coating weights, preferably between 45 to 60 ° C. and thus significantly below the commonly used Treatment temperatures. Treatment temperatures of 25 ° C are possible in special process combinations and specially adjusted phosphating solutions.

The process accelerated according to the invention has the further advantage that the sludge formation is largely suppressed. In combination with the lower treatment temperatures, the incrustation of the heating register is almost completely avoided. The sludge formation in the bath is considerably smaller than in the known phosphating baths which work with continuous or repeated additions of sodium nitrite as accelerators. The baths according to the invention need e.g. B. in diving operation and normal throughput only to be desludged every 12 to 15 months.

The method accelerated according to the invention also has the advantage of still delivering excellent values with regard to paint adhesion and corrosion protection when the normal zinc phosphating technology is used. Surprisingly, the process engineering advantages of normal zinc phosphating technology can be combined with the application engineering advantages of low zinc phosphating technology.

The accelerated according to the invention provides the new and surprising effect that the zinc phosphate baths can be operated immediately with very high bath loads and low temperatures without incorporation. Furthermore, a particularly economical production of the desired phosphate coatings is possible. This is due to the low consumption of chemicals required to produce a certain layer weight.

With the process accelerated according to the invention, coating weights of 0.2 to 30 g / m ² for steel and of 0.5 to 3.0 g / m ² for galvanized steel can be achieved. The respective value results from the type of treatment, the treatment time, the accelerator concentration and the temperature of the phosphating bath solutions used. As a particular advantage of the method according to the present invention, it can be seen that with otherwise constant parameters of the method, it is possible to vary the bed weights within the specified limits by changing the treatment temperature. Accordingly, higher coating weights during phosphating can be achieved by increasing the temperature. This effect is particularly pronounced in the temperature range between 45 and 60 ° C.

The process accelerated according to the invention is carried out within a process sequence known to the person skilled in the art, which consists of cleaning the metal surfaces, water rinsing, optionally preactivation with a solution containing titanium salt, phosphating with formation of the phosphate layer, water rinsing, post-treatment (passivation) and rinsing with demineralized water.

A characteristic feature of the process accelerated according to the invention is furthermore that the preactivation with a solution containing titanium salt can be dispensed with. In this case, the process sequence consists of a cleaning step with a strongly alkaline cleaner, subsequent rinsing, phosphating with the formation of the phosphate layer, post-treatment (passivation) and rinsing with deionized water.

The process for the preparation of phosphate coatings on steel and iron using an acidic zinc phosphate solution accelerated according to the invention at temperatures of 45 to 60 ° C in the immersion process is characterized in that bath solutions can be used which are prepared with aqueous acidic concentrates in which the weight ratio is widely variable from zinc to phosphate without the advantages according to the invention, such as reduced sludge accumulation, extremely fine crystalline layer formation, possibly also eliminating the need for preactivation with solutions containing titanium salts, fully formed phosphate layers, being lost at low treatment temperatures. A weight ratio of zinc to phosphate of 1: 1 to 12 has proven to be particularly advantageous.

The processes accelerated with the compounds of the general formulas (I), (11) and (111) as a component according to the present invention lead to phosphate layers which are very fine-grained. By changing the accelerator ratio and the treatment times and in particular by varying the treatment temperatures, it is possible to adapt the quality of the phosphate coatings in terms of layer weight and fine grain to the particular requirements.

The fine-grained phosphate coatings offer excellent corrosion protection, as a review based on the test methods mentioned in the examples showed. It also shows that the fine-grained phosphate layers in particular represent an excellent anchorage for subsequent applied lacquer coatings. The process accelerated according to the invention is particularly advantageous as a pretreatment before electrocoating, in particular cathodic electrocoating. The metal surfaces covered with the phosphate layers can not only be painted, but can also be coated with different types of materials.

Another important advantage is that the process according to the process accelerated according to the invention is characterized by reduced sludge and crust formation in the phosphating plants, which leads to economical process management and an extended service life of the phosphating solution.

The phosphating solution used in carrying out the process accelerated according to the invention is normally prepared as an acid concentrate and diluted accordingly before use. in the Concentrate can have a sufficiently high free acid content to avoid solid separation during storage, when the temperature drops or during transport. In use, ie when preparing and supplementing the layer-forming Pfiosphatierbades, the concentrate is diluted to the desired concentration and adjusted to the required pH or the free acid content. The continuously used phosphating solution can be supplemented with the aid of a supplementary solution which contains all active constituents or with the use of several supplementary solutions which contain all active constituents in their entirety.

The invention is illustrated by the following examples.

• A. Lackhaftung
  • 1. Gitterschnitt nach DIN 53 151
  • 2. Erichsen-Tiefung nach DIN ISO 15 20
  • 3. Dornbiegeversuch nach DIN 53 152
• B. Korrosionstests
  • 1. Salzsprühtest nach DIN 50 021
    • a) mit Einzelschnitt, Auswertung nach DIN 53 167
    • b) Blasengrad, Auswertung nach DIN 53 209
    • c) Rostgrad, Auswertung nach DIN 53 210
• 2. Steinschlagtest nach VW-Prüfvorschrift Nr. 3.17.1 vom 6.1.1981, Auswertung nach optischer Vorlage (Fotovergleich 1 bis 10)
• 3. Kondenswasser-Prüfklimate nach DIN 50 017
• 4. Wechselklimatest nach VW-Prüfvorschrift P-W-1210

The following tests were carried out to determine the adhesion of a varnish subsequently applied to the phosphated sheets and to determine the corrosion resistance:

• A. Paint liability
  • 1. Cross cut according to DIN 53 151
  • 2. Erichsen cupping according to DIN ISO 15 20
  • 3rd mandrel bending test according to DIN 53 152
• B. Corrosion Tests
  • 1. Salt spray test according to DIN 50 021
    • a) with single cut, evaluation according to DIN 53 167
    • b) Degree of bubbles, evaluation according to DIN 53 209
    • c) Degree of rust, evaluation according to DIN 53 210
• 2nd stone chip test according to VW test specification No. 3.17.1 from 6.1.1981, evaluation according to optical template (photo comparison 1 to 10)
• 3. Condensate test climates according to DIN 50 017
• 4. Alternating climate test according to VW test specification PW-1210

example 1

A powdery mixture of the following composition was first prepared:

This was then dissolved in water at a concentration of 12.0 g / l. 1.5 g / l of benzenesulfanilide was added to this solution as an accelerator component. The pH of the solution thus prepared was 3.5.

With the solution produced in this way, galvanized steel sheets were cleaned, degreased and coated with a phosphate layer by spray treatment at 50 ° C. and a treatment time of 120 s.

It was then rinsed with cold water for 30 s and the sheets were then subjected to a spray treatment with a solution containing Cr (VI) / Cr (III) ions at room temperature for 30 s. After this operation, the sheets were rinsed with demineralized water for 10 s and then dried in an oven at 130 ° C. for 5 minutes. The sheets treated in this way were coated with a powder coating and then passed to the tests for determining the corrosion resistance and the paint adhesion. The properties observed in each case were excellent.

Example 2

Concentrate A was first prepared by mixing the following components in a container made of plastic or stainless steel:

Aus beiden Konzentraten wurde eine für die Spritzbehandlung bestimmte Phosphatierlösung hergestellt, indem

• 30 g/I des Konzentrates A und
• 20 g/I des Konzentrates B
  in Wasser gelöst wurden. Die Gesamtsäurepunktzahl, titriert mit einer 10 ml-Badprobe mit 0,1 N Natriumhydroxidlösung gegen Phenolphthalein, war 14. Die freie Säure, bestimmt durch Titration einer 10 ml-Badprobe mit 0,1 N Natriumhydroxidlösung gegen Bromkresolgrün, betrug 0,7.

A concentrate B was prepared in a second container by stirring the following components together:

A phosphating solution intended for spray treatment was prepared from both concentrates by

• 30 g / l of concentrate A and
• 20 g / l of concentrate B
  were dissolved in water. The total acid score, titrated with a 10 ml bath sample with 0.1 N sodium hydroxide solution against phenolphthalein, was 14. The free acid, determined by titration of a 10 ml bath sample with 0.1 N sodium hydroxide solution against bromocresol green, was 0.7.

Cold-rolled steel sheets were subjected to the following process: First, the sheets were spray-treated with an alkaline cleaner (based on sodium hydroxide, pentasodium tripolyphosphate and surfactant) at 55 ° C. for 25 seconds. This was followed by a second cleaning by spraying with an alkaline cleaner (based on disodium hydrogenphosphate, activating titanium salt and surfactant) at 45 ° C. for 25 seconds. Then it was rinsed with cold water for 25 seconds.

The treatment with the phosphating solution described above was then carried out by spraying at 55 ° C. for 60 seconds. The phosphated sheets were rinsed cold for 25 seconds and then with a solution containing Cr (VI) / Cr (III) ions at a pH from 4.0 treated at 30 ° C for 30 sec. in spraying. This was followed by rinsing with fully demineralized water for 10 seconds. Finally, the sheets were dried in an oven at 110 ° C. for 4 minutes.

The sheets treated in this way were dip-coated cathodically with an electrodeposition paint from BASF. The tests to determine resistance to corrosion and various other physical properties gave excellent results.

Example 3

In einem zweiten Behälter wurde ein Konzentrat B aus folgenden Bestandteilen zusammengerührt.

Aus beiden Konzentraten wurde eine für die Tauchbehandlung bestimmte Phosphatierlösung hergestellt, indem

• 45 g/l des Konzentrates A und
• 10 g/l des Konzentrates B
  in Wasser gelöst wurden. Die Punktzahl der Gesamtsäure, titriert an einer 10 ml-Badprobe mit 0,1 N Natriumhydroxidlösung gegen Phenolphthalein war 25. Die freie Säure, bestimmt durch Titration einer 10 ml-Badprobe mit 0,1 N Natriumhydroxidlösung gegen Bromkresolgrün betrug 1,9.

First, concentrate A was prepared by mixing the following ingredients in a plastic or stainless steel container:

In a second container, a concentrate B of the following components was stirred together.

A phosphating solution intended for immersion treatment was prepared from both concentrates by

• 45 g / l of concentrate A and
• 10 g / l of concentrate B
  were dissolved in water. The total acid score titrated on a 10 ml bath sample with 0.1 N sodium hydroxide solution against phenolphthalein was 25. The free acid, determined by titration of a 10 ml bath sample with 0.1 N sodium hydroxide solution against bromocresol green, was 1.9.

Cold rolled steel sheets were subjected to the following procedures.

First, the sheets were immersed in an alkaline cleaner (based on sodium hydroxide, water glass, sodium orthophosphate and surfactant) at 70 ° C for 10 minutes. treated. Then 3 min. rinsed with water. It was then treated with a hydrochloric acid-containing pickling agent at 25 ° C. for 25 min. stained. This was followed by treatment with the phosphating solution described above by immersion at 50 ° C. for 10 minutes. The phosphated sheets were rinsed with water for 3 minutes and then with a solution containing Cr (VI) / Cr (III) ions at a pH of 4.0 at 40 ° C. for 3 min. treated in diving and finally with demineralized water for 2 min. rinsed.

The sheets treated in this way were dip-coated cathodically with an electro-dip coating from Wiederhold / ICI. The phosphated and painted sheets were then subjected to tests to determine corrosion resistance and other physical properties. The properties observed in each case were excellent.

Example 4

In einem zweiten Behälter wurde ein Konzentrat B aus folgenden Komponenten zusammengerührt :

Aus beiden Konzentraten wurde eine für die Spritzbehandlung bestimmte Phosphatierlösung hergestellt, indem

• 25 g/l des Konzentrates A und
• 5 g/I des Konzentrates B
  in Wasser gelöst wurden. Die Gesamtsäurepunktzahl, titriert an einer 10 ml-Badprobe mit 0,1 N Natriumhydroxidlösung gegen Phenolphthalein, war 14. Die freie Säure, bestimmt durch Titration einer 10 ml-Badprobe mit 0,1 N Natriumhydroxidlösung gegen Bromkresolgrün betrug 0,8.

A concentrate A was first prepared by mixing the following components in a container made of plastic or stainless steel:

In a second container, a concentrate B consisting of the following components was stirred together:

A phosphating solution intended for spray treatment was prepared from both concentrates by

• 25 g / l of concentrate A and
• 5 g / l of concentrate B
  were dissolved in water. The total acid score titrated on a 10 ml bath sample with 0.1 N sodium hydroxide solution against phenolphthalein was 14. The free acid, determined by titration of a 10 ml bath sample with 0.1 N sodium hydroxide solution against bromocresol green, was 0.8.

• Zuerst wurden die Bleche mit einem alkalischen Reiniger (auf Basis Natriumhydroxid, Pentanatriumtripolyphosphat und Tensid) bei 55 °C während 25 sec. im Spritzen behandelt. Dann folgte eine zweite Reinigung im Spritzen mit einem alkalischen Reiniger (auf Basis Dinatriumhydrogenphosphat, aktivierend wirkendes Titansalz und Tensid) bei 45 °C während 25 sec. Danach wurde 25 sec. in kaltem Wasser gespült. Anschließend erfolgte die Behandlung mit der oben beschriebenen Phosphatierlösung durch Spritzen bei 55 °C während 50 sec. Die phosphatierten Bleche wurden 25 sec. kalt mit Wasser gespült und danach mit einer Cr (VI)/Cr (III)-Ionen enthaltenden Lösung bei einem pH-Wert von 4,0 bei 30 °C während 25 sec. im Spritzen behandelt. Es folgte ein Spülen mit voll entsalztem Wasser im Spritzen während 10 sec. Zum Schluß wurden die Bleche 4 Minuten bei 110 °C im Ofen getrocknet.

Cold rolled steel sheets were subjected to the following process steps:

• First, the sheets were sprayed with an alkaline cleaner (based on sodium hydroxide, pentasodium tripolyphosphate and surfactant) at 55 ° C for 25 seconds. This was followed by a second cleaning by spraying with an alkaline cleaner (based on disodium hydrogenphosphate, activating titanium salt and surfactant) at 45 ° C. for 25 seconds. Thereafter, it was rinsed in cold water for 25 seconds. The treatment with the phosphating solution described above was then carried out by spraying at 55 ° C. for 50 seconds. The phosphated sheets were rinsed cold with water for 25 seconds and then with a solution containing Cr (VI) / Cr (III) ions at a pH -Value of 4.0 treated at 30 ° C for 25 seconds in spraying. This was followed by rinsing with demineralized water in a syringe for 10 seconds. Finally, the sheets were dried in an oven at 110 ° C. for 4 minutes.

The sheets treated in this way were dip-coated cathodically with an electro dip coating from Herberts GmbH. The tests to determine resistance to corrosion and various other physical properties gave excellent results.

Example 5

In einem zweiten Behälter wurde ein Konzentrat B aus folgenden Bestandteilen zusammengerührt.

Aus beiden Konzentraten wurde eine für die Spritzbehandlung bestimmte Phosphatierlösung hergestellt, indem

• 30 g/I des Konzentrates A und
• 20 g/I des Konzentrates B
  in Wasser gelöst wurden. Die Punktzahl der Gesamtsäure, titriert an einer 10 ml-Badprobe mit 0,1 N Natriumhydroxidlösung gegen Phenolphthalein war 14. Die freie Säure, bestimmt durch Titration einer 10 ml-Badprobe mit 0,1 N Natriumhydroxidlösung gegen Bromkresolgrün betrugt 0,7.

First, concentrate A was prepared by mixing the following ingredients in a plastic or stainless steel container:

In a second container, a concentrate B of the following components was stirred together.

A phosphating solution intended for spray treatment was prepared from both concentrates by

• 30 g / l of concentrate A and
• 20 g / l of concentrate B
  were dissolved in water. The total acid score titrated on a 10 ml bath sample with 0.1 N sodium hydroxide solution against phenolphthalein was 14. The free acid, determined by titration of a 10 ml bath sample with 0.1 N sodium hydroxide solution against bromocresol green, was 0.7.

• Zuerst wurden die Bleche mit einem alkalischen Reiniger (auf Basis Natriumhydroxid, Pentanatriumtripolyphosphat und Tensid) bei 55 °C während 25 sec. im Spritzen behandelt. Dann folgte eine zweite Reinigung im Spritzen mit einem alkalischen Reiniger (auf Basis Dinatriumhydrogenphosphat, aktivierend wirkendes Titansalz und Tensid) bei 45 °C während 25 sec. Danach wurde 25 sec. mit kaltem Wasser gespült.

Cold rolled steel sheets were subjected to the following process:

• First, the sheets were sprayed with an alkaline cleaner (based on sodium hydroxide, pentasodium tripolyphosphate and surfactant) at 55 ° C for 25 seconds. This was followed by a second cleaning by spraying with an alkaline cleaner (based on disodium hydrogenphosphate, activating titanium salt and surfactant) at 45 ° C. for 25 seconds. Then it was rinsed with cold water for 25 seconds.

The treatment with the phosphating solution described above was then carried out by spraying at 55 ° C. for 60 seconds. The phosphated sheets were rinsed cold for 25 seconds and then with a solution containing Cr (VI) / Cr (III) ions at a pH from 4.0 treated at 30 ° C for 30 sec. in spraying. This was followed by rinsing with demineralized water for 10 seconds. Finally, the sheets were dried in an oven at 110 ° C. for 4 minutes.

The sheets treated in this way were dip-coated cathodically with an electrodeposition paint from BASF. The tests to determine resistance to corrosion and various other physical properties gave excellent results.

Example 6

In einem zweiten Behälter wurde ein Konzentrat B aus folgenden Bestandteilen zusammengerührt :

Aus beiden Konzentraten wurde eine für die Spritzbehandlung bestimmte Phosphatierlösung hergestellt, indem

• 20,0 g/I des Konzentrates A und
• 60,0 g/I des Konzentrates B
  in Wasser gelöst wurden. Die Gesamtsäurepunktzahl, titriert an einer 10 ml-Badprobe mit 0,1 N Natriumhydroxidlösung gegen Phenolphthalein, war 29. Die freie Säure, bestimmt durch Titration einer 10 ml-Badprobe mit 0,1 N Natriumhydroxidlösung gegen Brom-Kresolgrün, betrug 0,8.

A concentrate A was first prepared by mixing the following components in a container made of plastic or stainless steel:

In a second container, a concentrate B consisting of the following components was stirred together:

A phosphating solution intended for spray treatment was prepared from both concentrates by

• 20.0 g / l of concentrate A and
• 60.0 g / l of concentrate B
  were dissolved in water. The total acid score titrated on a 10 ml bath sample with 0.1 N sodium hydroxide solution against phenolphthalein was 29. The free acid, determined by titration of a 10 ml bath sample with 0.1 N sodium hydroxide solution against bromine-cresol green, was 0.8.

Cold-rolled steel sheets were subjected to the following process steps: First, the sheets were treated with an alkaline cleaner (based on sodium orthophosphate, sodium pyrophosphate, activating titanium salt and surfactant) at 55 ° C. for 60 s by spraying. Then it was rinsed with cold water for 30 seconds.

The treatment with the phosphating solution described above was then carried out by spraying at 55 ° C. for 90 s. The phosphated sheets were rinsed cold and then with a Cr (VI) / Cr (III) - Solution containing ions treated at pH 4.0 at room temperature for 30 s by spraying.

This was followed by rinsing with demineralized water in a syringe for 10 s, after which the sheets were dried in the oven at 130 ° C. for 5 minutes.

The sheets treated in this way were dip-coated cathodically with an electrodeposition paint from BASF. The tests to determine resistance to corrosion and various other physical properties gave excellent results.

Example 7

In einem zweiten Behälter wurde ein Konzentrat B aus folgenden Bestandteilen zusammengerührt :

Aus beiden Konzentraten wurde eine für die Spritzbehandlung bestimmte Phosphatierlösung hergestellt, indem

• 30,0 g/l des Konzentrates A und
• 45 g/I des Konzentrates B
  in Wasser gelöst wurden. Die Gesamtsäurepunktzahl, titriert an einer 10 ml-Badprobe mit 0,1 N Natriumhydroxidlösung gegen Phenolphthalein, war 29. Die freie Säure, bestimmt durch Titration einer 10 ml-Badprobe mit 0,1 N Natriumhydroxidlösung gegen Brom-Kresolgrün, betrug 0,8.

A concentrate was first prepared by mixing the following components in a plastic or stainless steel container:

In a second container, a concentrate B consisting of the following components was stirred together:

A phosphating solution intended for spray treatment was prepared from both concentrates by

• 30.0 g / l of concentrate A and
• 45 g / l of concentrate B
  were dissolved in water. The total acid score titrated on a 10 ml bath sample with 0.1 N sodium hydroxide solution against phenolphthalein was 29. The free acid, determined by titration of a 10 ml bath sample with 0.1 N sodium hydroxide solution against bromine-cresol green, was 0.8.

Cold-rolled steel sheets were subjected to the following process steps: First, the sheets were treated with an alkaline cleaner (based on sodium orthophosphate, sodium pyrophosphate, activating titanium salt and surfactant) at 55 ° C. for 60 s by spraying. Then it was rinsed with cold water for 30 seconds.

The treatment with the phosphating solution described above was then carried out by spraying at 55 ° C. for 90 s. The phosphated sheets were rinsed cold for 30 s and then sprayed with a solution containing Cr (VI) / Cr (III) ions at a pH of 4.0 at room temperature for 30 s.

This was followed by rinsing with demineralized water in a syringe for 10 s, after which the sheets were dried in the oven at 130 ° C. for 5 minutes.

The sheets treated in this way were dip-coated cathodically with an electrodeposition paint from ICI / Wiederhold. The tests to determine resistance to corrosion and various other physical properties gave excellent results.

Example 8

A concentrate was prepared by mixing the following ingredients in a stainless steel container.

• 40 g/I dieses Konzentrates und
• 2 g/I N-Cyclohexansulfamin-saures Natrium
  in Wasser gelöst wurden. Die Punktzahl der Gesamtsäure, titriert an einer 10 ml-Badprobe mit 0,1 N Natriumhydroxidlösung gegen Phenolphthalein, war 10. Die freie Säure, bestimmt durch Titration einer 10 ml-Badprobe mit 0,1 N Natriumhydroxidlösung gegen Brom-Kresolgrün, betrug 2,0.

A phosphating solution intended for immersion treatment was prepared from this concentrate by

• 40 g / l of this concentrate and
• 2 g / l N-cyclohexanesulfamine-acidic sodium
  were dissolved in water. The total acid score titrated on a 10 ml bath sample with 0.1 N sodium hydroxide solution against phenolphthalein was 10. The free acid, determined by titration of a 10 ml bath sample with 0.1 N sodium hydroxide solution against bromine-cresol green, was 2. 0.

• Zuerst wurden die Ronden mit einem alkalischen Reiniger (auf Basis Natriumhydroxid, Wasserglas, Natriumcarbonat, Natriumorthophosphat und Tensid) bei 70 °C im Tauchen 10 Minuten behandelt. Dann wurde 3 Minuten mit Wasser gespült. Dann wurde mit einem schwefelsäurehaltigen inhibierten Beizmittel bei 25 °C 10 Minuten gebeizt und wieder 3 Minuten mit Wasser gespült. Darauf erfolgte die Behandlung der Ronden mit der oben beschriebenen Phosphatierlösung durch 8-minütiges Tauchen bei 50 °C. Diese Behandlung führte zu einer Schichtauflage von 15 g/m^2.

Round blanks made of steel intended for cold forming (gear wheel production) were subjected to the following process steps:

• First, the round blanks were treated with an alkaline cleaner (based on sodium hydroxide, water glass, sodium carbonate, sodium orthophosphate and surfactant) at 70 ° C. for 10 minutes while diving. Then it was rinsed with water for 3 minutes. It was then pickled with an inhibited pickling agent containing sulfuric acid at 25 ° C. for 10 minutes and rinsed again with water for 3 minutes. Then the round blanks were treated with the phosphating solution described above by dipping at 50 ° C. for 8 minutes. This treatment resulted in a layer coverage of 15 g / m ^2.

The phosphated blanks were rinsed with water for 3 minutes and then soaped with a soap-containing aqueous solution (6% sodium stearate, 1% sodium myristate) at 80 ° C. for 5 minutes.

Gears were made from the blanks treated in this way.

Example 9

Aus diesem Konzentrat wurde eine für die Tauchbehandlung bestimmte Phosphatierlösung hergestellt, indem

• 80 g/I dieses Konzentrates und
• 3 g/I N-Cyclohexansulfamin-saures Natrium
  in Wasser gelöst wurden. Die Punktzahl der Gesamtsäure, titriert an einer 10 ml-Badprobe mit 0,1 N Natriumhydroxid gegen Phenolphthalein, war 30. Die freie Säure, bestimmt durch Titration einer 10 ml-Badprobe mit 0,1 N Natriumhydroxidlösung gegen Form-Kresolgrün, betrug 1,8.

A concentrate was made by mixing the following ingredients in a stainless steel container:

A phosphating solution intended for immersion treatment was prepared from this concentrate by

• 80 g / l of this concentrate and
• 3 g / l N-cyclohexanesulfamine acidic sodium
  were dissolved in water. The total acid score, titrated on a 10 ml bath sample with 0.1 N sodium hydroxide against phenolphthalein, was 30. The free acid, determined by titration of a 10 ml bath sample with 0.1 N sodium hydroxide solution against form cresol green, was 1. 8th.

• Zuerst wurden die Ronden mit einem alkalischen Reiniger (auf Basis Natriumhydroxid, Wasserglas, Natriumorthophosphat und Tensid) bei 75 °C im Tauchen 10 Minuten behandelt. Dann wurde 3 Minuten mit Wasser gespült. Dann wurde mit einem schwefelsäurehaltigen inhibierten Beizmittel bei 30 °C 10 Minuten gebeizt und wieder 3 Minuten mit Wasser gespült. Darauf erfolgte die Behandlung der Ronden mit der oben beschriebenen Phosphatierlösung durch 5-minütiges Tauchen bei 50 °C. Diese Behandlung führte zu einer Schichtauflage von 25 g/m².

Steel round blanks intended for cold forming (gear wheel production) were subjected to the following process steps:

• First, the blanks were treated with an alkaline cleaner (based on sodium hydroxide, water glass, sodium orthophosphate and surfactant) at 75 ° C for 10 minutes while diving. Then it was rinsed with water for 3 minutes. Then it was pickled with a sulfuric acid-containing inhibited pickling agent at 30 ° C. for 10 minutes and rinsed again with water for 3 minutes. Then the round blanks were treated with the phosphating solution described above by dipping at 50 ° C. for 5 minutes. This treatment resulted in a layer coverage of 25 g / m ² .

The phosphated blanks were rinsed with water for 3 minutes and then soaped with a soap-containing aqueous solution (6% sodium stearate, 1% sodium myristate) at 80 ° C. for 5 minutes.

Gears were made from the blanks treated in this way.

Claims (7)

1. The use of one or more compounds corresponding to general formula (I), (II) or (III)

in which

R' represents hydrogen, a linear or branched C_l-C₄ alkyl radical, a 5- or 6-membered saturated carbocyclic or heterocyclic radical or an at least 6-membered aryl or aralkyl radical and

R² represents a hydroxy group, a group of the formula ―O―M^-, where M- is an alkali metal or

ammonium ion, or an at least 6-membered aromatic ring optionally substituted by a hydroxy or amino group, with the proviso that, there R¹ is hydrogen, R² may not be an OH or O―M⁺ group ;

in which R³ represents hydrogen, a hydroxy or ammonium group, and/or alkali metal and ammonium salts of compounds corresponding to the formula ;

in which R⁴ is hydrogen or a linear or branched C_l-C₄ alkyl radical and M⁺ is as defined above ;
as accelerating and layer refining component, in a quantity of 0.1 to 6 g/I, in phosphating solutions based on zinc phosphate and/or iron phosphate and/or zinc iron phosphate, of the type used for applying phosphate coatings to metal surfaces, in addition to other components typically used in such phosphating solutions.

2. The use claimed in claim 1, characterized in that one or more compounds from the group consisting of N-cyclohexanesulfamic acid and salts thereof, benzenesulfanilide, benzoic acid sulfimide, 1,2,3-oxathiazin-4 (3H)-one potassium and its 6-methyl derivative.

3. The use claim in claims 1 and 2, characterised in that compounds corresponding to general formulae (I), (II) and/or (III) are used as the accelerating and layer-refining component together with chlorate in a ratio of those compounds to chlorate of (0.1-10.0) : 1.

4. The use claimed in claims 1 and 2, characterized in that compounds corresponding to general formulae (I), (II) and/or (III) are used as the accelerating and layer-refining component together with molybdate in a ratio of those compounds to molybdate of (10-100) : 1.

5. The use claimed in claims 1 to 4, characterized in that the accelerating and layer-refining components are used in phosphating solutions additionally containing Ni, Co and/or Fe ions of which the total quantity should not exceed 3.0 g/I.

6. The use claimed in claim 1 to 5, characterized in that the accelerating and layer-refining components are used in phosphating solutions having a pH value in the range from 1.8 to 5.8 and preferably in the range from 2.0 to 3.5.

7. The use claimed in claims 1 to 6, characterized in that the accelerating and layer-refining components are used in phosphating solution having temperatures in the range from 25 to 70 °C and preferably in the range from 45 to 60 °C.