JP2007507607A - Method for pickling metal surfaces by using alkoxylated alkanols - Google Patents

Abstract

  A method of pickling a metal surface by treating the metal surface with a composition comprising water, at least one acid, an alkyne alkoxylate and optionally another additive. In a preferred embodiment, an alkyne alkoxylate is used with a complexing agent.

Description

  The present invention relates to a method of pickling a metal surface by treating the metal surface with a composition comprising water, at least one acid, an alkyne alkoxylate, and optionally another additive. In a preferred embodiment, alkyne alkoxylates are used with complexing agents.

In pickling, the surface of the material is treated with a pickle and the surface is changed by chemical methods. Here, the undesired surface phase is removed and, optionally, a protective layer or an effect layer is formed. In the case of metal surfaces, pickling may be used to remove, for example, rust or scale layers, and / or other impurities such as grease, oil, or lime from the surface, particularly to remove various oxide layers. And / or function to activate and / or protect the surface. Examples of the protective treatment include acid phosphoric acid treatment of the iron or steel surface. Here, the substantial element is a pickling attack (chemical action) on the metal. When phosphating with an acidic zinc phosphate solution, a large number of H ⁺ ions are consumed directly through the acid pickling attack on the metal at the metal surface and the pH increases locally. The zinc phosphate is deposited in a thin layer on the surface for the first time by the soluble product of zinc phosphate described above.

  Aqueous inorganic or organic acids, in particular hydrochloric acid, phosphoric acid or sulfuric acid, and conventional auxiliaries such as surfactants are used for pickling. The acid is intended to attack the surface layer and may be intended to attack the metal itself if appropriate, but it is usually not preferred if an excessive amount of metal dissolves. On the one hand, a large amount of pickling acid is consumed in this regard, and the pickling solution is contaminated with dissolved metal ions. The pickling tub must therefore be updated frequently. On the other hand, however, the surface is also damaged by so-called hydrogen embrittlement, especially in the case of iron and nickel. Therefore, pickling inhibitors are usually added to pickling preparations to prevent dissolution of the base metal or at least significantly reduce the dissolution rate without interfering with substantial dissolution of the surface layer. Added. Pickling using an inhibitor may also be referred to as inhibited pickling.

  Alkynol, such as 2-butyne-1,4-diol, 1-propyne-3-ol, or 1-ethynylcyclohexanol can be used as a pickling inhibitor. For example, it is described in Patent Document 1 (US3658720), Patent Document 2 (US3969260), or Patent Document 3 (JP-A60-208487). Patent Document 4 (WO 99/32687) discloses the use of 2-butyne-1,4-diol as an inhibitor in the acidic phosphoric acid treatment of steel strips galvanized on one side.

  Special care must be taken when handling alkynols. 2-butyne-1,4-diol and 1-propin-3-ol are classified as toxic substances and carcinogenic substances, respectively. Alkyne alkoxylates are generally known, for example from DE-A 224155. As disclosed in US Pat. No. 3,804,727, US Pat. No. 3,814,674, or US Pat. No. 4,834,742, these are bright electroplating additives, particularly in the electroplating of nickel or cobalt. Used as. Alkoxylated alkynols are not classified as toxic or carcinogenic.

Patent Document 8 (US 3004925) discloses the use of an ethoxylated butynediol derivative and an ethoxylated propinol derivative as a corrosion inhibitor in an aqueous solution. The OH group is modified in each case with a — (CH ₂ —CH ₂ O) _X group (where X is a value from 3 to 25). Further, the disclosed alkynols further have one or more alkyl, allyl, cycloalkyl, and aralkyl groups. Unsubstituted butanediol or propargyl alcohol is not disclosed.

US Pat. No. 5,215,675 discloses a composition comprising 10-50% water, 3-15% peroxide, and 40-70% ethyl lactate for removing lacquer from the surface. Has been. The composition may further optionally include ethoxylated butynediol and an acid as corrosion inhibitors. As another embodiment, from 55 to 60 percent of butyrolactone, 30 to 32% aqueous hydrogen peroxide, 9.5% formic acid, 1% of ethoxylated butanediol, 0.5% Na ₄ EDTA, And a composition comprising 4% surfactant.

US3658720 US3969260 JP-A60-208487 WO99 / 32687 US3804727 US3814667 US4832802 US3004925 US5215675

  It is an object of the present invention to provide a method for pickling metal surfaces in which butanediol or propinol is replaced by a suitable alternative and nevertheless better pickling inhibition is achieved. is there.

The inventor has the object of at least the following components:
(A) 60-99.99% by weight of a mixture of water and at least one acid,
(B) 0.01-2 mass% formula

Wherein the group R ¹ is, in each case, independently of each other, H or methyl, and the indices n and n ′ are independently of each other 1-10. A species of alkyne alkoxylate, and
(C) 0 to 38% by weight of one or more additives and / or auxiliaries,
It has been found that this is achieved by a method of pickling a metal surface, wherein the metal surface is treated with an acidic aqueous preparation comprising

  In a preferred embodiment, the pickling inhibitor is used in combination with a water-soluble complexing agent.

  Details of the present invention will be described below.

  This new method can in principle be used for pickling various types of metal surfaces. The metal may be an alloy or a pure metal. Examples include iron, cast iron, steel, nickel, zinc, brass or aluminum surfaces, and in each case a top metal layer in direct contact with the preparation is meant. The metal surface may also be a surface hardened steel such as, for example, hot-galvanized or zinc-plated steel. This method is particularly suitable for pickling the surface of (cast) iron, steel or aluminum and very suitable for pickling the surface of iron. This method is suitable for pickling the surface of strip metal, such as steel or aluminum.

  The metal surface may be the outer surface of a metal material, which is an amorphous product, such as, for example, a metal strip, sheet, or machine part. However, the metal surface may be an internal surface such as an internal surface of a pipeline, boiler, chemical plant or the like.

  In this new pickling method, unwanted surface layers and impurities are removed and, if desired, a protective layer and / or a functional layer is formed. The term “pickling” includes phosphating of metal surfaces. Undesirable surface layers are in particular inorganic layers, for example rust layers, substantial oxide layers such as scale layers, or layers formed between rolls of metals, for example steel. These may be layers applied for temporary corrosion protection, for example phosphate layers, or layers of other materials, for example carbonate layers such as lime layers or patina layers. Undesirable layers are furthermore thin layers of organic material, for example grease or oil layers.

  The preparation used in this new process comprises as component (a) water and at least one acid in an amount of 60-99.99% by weight. The percentages mentioned here and below are always based on the sum of all components of the preparation.

  The total amount of water and acid is preferably 70 to 99.99% by mass, very preferably 80 to 99.99% by mass.

  Acids are inorganic acids such as hydrochloric acid, hypochlorous acid and chlorous acid, sulfuric acid, phosphoric acid, or phosphorous acid, or organic acids such as formic acid, methanesulfonic acid, acetic acid, citric acid, succinic acid, or amidosulfonic acid. good. Of course, a mixture of different acids may also be used, for example a mixture of hydrochloric acid and phosphoric acid. The acid is preferably hydrochloric acid, sulfonic acid, methanesulfonic acid or phosphoric acid.

  The respective amounts of water and acid depend on the one hand on the intended use of the preparation and also on the type of acid. Due to the use of phosphoric acid, in certain cases, the solvent consists exclusively of concentrated (ie, 85% strength) phosphoric acid, so it is advantageous to dilute more with acids other than phosphoric acid. If an acid other than phosphoric acid is used, the preparation usually contains at least 50% by weight of water, preferably at least 60% by weight. The total amount of water in the preparation is calculated as the sum of the water added with the acid and the water added in the pure state, or in solution or other materials.

  Component (b) in the preparation used in the new process has a formula of 0.01-2% by weight,

で表される、少なくとも１種のアルキンアルコキシレートを含む。指数ｎ及びｎ’は、互いに独立して、１〜１０である。このようなアルコキシ基が、特にオキシアルキル化により得ることができ、又は工業ポリグリコールから開始して得ることができることは、当業者にとって公知である。上述したｎの値は、従って、鎖の平均長さであり、平均値は、当然に自然数である必要ななく、しかし、所望の有理数であって良い。ｎ及びｎ’は、１〜３の数が好ましい。

And at least one alkyne alkoxylate represented by: The indices n and n ′ are 1 to 10 independently of each other. It is known to those skilled in the art that such alkoxy groups can be obtained in particular by oxyalkylation or can be obtained starting from industrial polyglycols. The value of n described above is therefore the average length of the chain, and the average value need not of course be a natural number, but can be the desired rational number. n and n ′ are preferably 1 to 3.

The radicals R ¹ in (I) and (II) are in each case independently of one another H or methyl. The alkyleneoxy group may be a group derived exclusively from ethylene oxide units or a group derived exclusively from propylene oxide. However, the alkyleneoxy group may be a group having both an ethylene oxide unit and a propylene oxide unit.

  Polyoxypropylene units are preferred.

  Of course, mixtures of (I) and (II) and / or mixtures of different compounds (I) or different compounds (II) may also be used. It is preferred to use compound (I).

  It is preferred to use 0.05 to 2% by weight of (I) and / or (II), particularly preferably 0.075 to 1.5, very preferably 0.1 to 1.0% by weight. All concentration data are based on ready-to-use compositions. It is of course possible to make the concentrate first and dilute it to the desired concentration only on site.

  The amount of (I) and / or (II) also depends on the type and amount of acid used and the temperature at which the preparation is used. The higher the acid concentration, the higher the concentration usually used in each case of pickling inhibitors (I) and / or (II). The higher the temperature, the higher the pickling inhibitor concentration should usually be. The amounts listed below have been found to be particularly useful for use at room temperature.

  The compounds used can be obtained in a known manner by oxyalkylation of butanediol or propargyl alcohol, for example as described in DE-A 2241155 or US38146674.

  The preparation used in the process usually further comprises one or more additives or auxiliaries, but these additions are not absolutely essential in all cases.

  The amount of such additives is from 0 to 38, preferably from 0.01 to 30, particularly preferably from 0.1 to 20% by weight.

  The auxiliary contains in particular 0.01 to 20% by weight of at least one surfactant. Preferably, 0.1 to 10, particularly preferably 0.5 to 8% by weight of a surfactant is used. Examples of suitable surfactants include conventional anionic or nonionic surfactants.

Particularly suitable nonionic surfactants are:
Alkoxylated C ₈ -C ₂₂ -alcohols such as fatty alcohol alkoxylates, oxo alcohol alkoxylates and Gerve alcohol ethoxylates: alkoxylation is carried out with ethylene oxide, propylene oxide and / or butylene oxide be able to. Block copolymers or random copolymers may be present. These usually comprise 2 to 50, preferably 3 to 20 mol of at least one alkylene oxide per mole of alcohol. A preferred alkylene oxide is ethylene oxide. The alcohol preferably contains 10 to 18 carbon atoms.

C ₆ -C ₁₄ - alkyl chain and 5 to 30 moles of alkylene oxide / mole, alkylphenol alkoxylates, particularly alkylphenol ethoxylates.
C ₈ -C ₂₂ - alkyl chain, preferably C ₁₀ -C ₁₈ - includes alkyl chains, and typically from 1 to 20, preferably an alkyl polyglucoside containing glucoside units of 1.1 to 5.

  N-alkyl glucamides, fatty acid amide alkoxylates, fatty acid alkanolamide alkoxylates and block copolymers of ethylene oxide, propylene oxide and / or butylene oxide.

Examples of suitable anionic surfactants are:
(Fatty) alcohol sulfates of 8 to 22, preferably 10 to 18 carbon atoms, in particular C ₉ C ₁₁ -alcohol sulfate, C ₁₂ C ₁₄ -alcohol sulfate, C ₁₂ -C ₁₈ -alcohol sulfate, Lauryl sulfate, seryl sulfate, myristyl sulfate, palmityl sulfate, stearyl sulfate, and tallow fatty alcohol sulfate.

Sulfated, alkoxylated C ₈ -C ₂₂ - alcohol (alkyl ether sulfates): compounds of this type are, for example, first C ₈ -C ₂₂ - alcohol, preferably, C ₁₀ -C ₁₈ - alcohol, e.g. It is obtained by alkoxylating a fatty alcohol and then sulphating the alkoxylated product.

Linear (linear) C ₈ -C ₂₀ - alkyl benzene sulfonate (LAS), preferably linear C ₉ -C ₁₃ - alkyl benzene sulfonates and, - alkyl toluenesulfonate.

Alkyl sulphonates, particularly C ₈ -C ₂₄ - alkene sulfonate, preferably, C ₁₀ -C ₁₈ - alkene sulfonate.

C ₈ -C ₂₄ - is a soap, such as Na and K salts of carboxylic acids.

  The anionic surfactant is preferably added in a salt state. Suitable cations are, for example, alkali metal ions such as sodium, potassium and lithium, ammonium salts such as hydroxyethylammonium, di (hydroxyethyl) ammonium and tri (hydroxy) ammonium salts.

Particularly suitable cationic surfactants are:
C ₇ -C ₂₂ - alkyl amine;
N, N-dimethyl -N- (hydroxy -C ₇ -C ₂₅ - alkyl) ammonium salts;
Mono- and di- (C ₇ -C ₂₅ -alkyl) dimethylammonium compounds quaternized with alkylated goods;
Quaternized esterified mono-, di- and trialkanolamines esterified with ester quat, in particular C ₈ -C ₂₂ -carboxylic acids;
Imidazoline water, especially 1-alkyl imidazolium salts of formula III or IV

(However,
R ² is C ₁ -C ₂₅ -alkyl or C ₂ -C ₂₅ -alkenyl;
R ³ is C ₁ -C ₄ -alkyl or hydroxy-C ₁ -C ₄ -alkyl;
R ⁴ is, C ₁ -C ₄ - alkyl, or hydroxy -C ₁ -C ₄ - alkyl, or a group ^{R 4 - (CO) -X- (} CH 2) P -, (X: -O- or -NH -; P: 2 or 3),
At least one group R ² is C ₇ -C ₂₂ -alkyl. ).

  Of course, a plurality of different surfactants may be used. The person skilled in the art makes an appropriate selection among the surfactants, depending on the desired application. Recommended preparations are described in the relevant literature, for example in the technical information of the BASF AG, Technology Reinigsmitel, January 1993 edition.

  It is preferable to use a nonionic surfactant.

  It is particularly preferred that the preparation used contains one or more water-soluble complexing agents as a separate component. The complexing agent has a synergistic effect when used with a pickling inhibitor. When added to the pickling acid, the complexing agent has been found to facilitate the removal of the metal. However, when they are used in combination with alkoxylated alkynols as pickling inhibitors according to the present invention, the inhibitory effect of pickling inhibitors is not reduced by complexing agents, but conversely enhanced. Even do. In the experiment, it was possible to improve the suppression effect by adding complexing agents up to 60%.

  The complexing agent is an at least bidentate water-soluble ligand capable of forming a chelate complex. The ligand contains an acidic group and preferably contains a COOH group. As described below, the complexing agent has at least two COOH groups. Bidentate to hexadentate ligands are preferred, and bidentate to tetradentate ligands are particularly preferred. One skilled in the art knows that the coordinating group in the chelating ligand is arranged so that the ligand can form one or more rings with the metal, especially a five-membered ring. Yes.

  The ligand can further comprise another atom or group capable of forming a coordinate bond to the metal ion. Examples of these are in particular OH groups and nitrogen-containing groups such as primary amino, secondary amino and tertiary amino groups. A tertiary amino group is preferred.

Preferred complexing agents for practicing the present invention include a ligand derived from a compound having a primary amino group and in which the H atom on the amino group is replaced by a —CH ₂ —COOH group. Examples include ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), hydroxyethylethylenediaminetriacetic acid (HEDTA), nitrilotriacetic acid (NTA), or methylglycine diacetic acid (MGDA). Ethylenediaminetetraacetic acid and methyl glycine diacetate are preferably used to carry out the present invention, and methyl glycine diacetate is very particularly preferred. The complexing agent can be used in the acid state or in the salt state.

The complexing agent may be a polymerizable complexing agent. Suitable polymerizable complexing agents are in particular from polymers having primary and / or secondary amino groups and where some or all of the H atoms on the amino groups are replaced by —CH ₂ —COOH groups. It is what is induced. The polymerizable complexing agent is preferably polyethyleneimine modified with —CH ₂ —COOH groups. Usually, at least 50%, preferably at least 60%, particularly preferably at least 75% of the H atoms on the amino group should be substituted. A method for producing such a polymerizable complexing agent is described in WO2004 / 001099.

  Those skilled in the field of water-soluble complexing agents know that the solubility of complexing agents including COOH in water depends on the pH. The pH chosen for each intended use should therefore be chosen as the reference point in each case. For the intended use, complexing agents that are poorly soluble at one pH may have sufficient solubility at other pHs.

  When present, the complexing agent is usually used in an amount of 0.01 to 10% by weight. It is preferably used in the range of 0.1 to 10% by mass, particularly preferably 0.1 to 5% by mass. The mass ratio of the complexing agent to the pickling inhibitor is usually 100: 1 to 1: 100, preferably 50: 1 to 1:50, particularly preferably 5: 1 to 1:10. Depending on the acid concentration, the following amounts have been found to be particularly suitable for use at room temperature.

The pH of the composition is determined by one skilled in the art according to the intended use. The pH of the composition can be set by the type and amount of acid and optionally other components depending on the intended use. A suitable buffer system such as phosphate buffer or citrate buffer can also be used to stabilize the pH. Usually, the pH is from 0 to less than 7, preferably from 6.5 to 2, particularly preferably from 3 to 6.
(A) a mixture of 60 to 99.97% by weight of water and at least one acid;
(B) 0.01-2% by weight of at least one alkyne alkoxylate,
(C) 0.01 to 20% by mass of at least one surfactant, and
(D) 0.01 to 10% by weight of at least one chelate-forming complexing agent,
Preparations containing are particularly preferred for carrying out the new process.

  Most preferably, the amount is (a) 70-98.9% by weight, (b) 0.1-2% by weight, (c) 0.5-15% by weight, (d) 0.5-10% by weight. %.

  In a further preferred embodiment of the invention, the pickling inhibitor used according to the invention is a water-soluble cationic, nitrogen-containing polymer (V) comprising quaternary ammonium groups,

(However, R ⁵ and R ^{5 ′} are the same or different and are saturated or unsaturated, substituted or unsubstituted aliphatic group, saturated or unsaturated, substituted or unsubstituted alicyclic group, or substituted. Or an unsubstituted araliphatic group). The group A bonded to the ammonium group is a hydrocarbon group, in particular an alkylene group into which other functional groups and / or heteroatoms may be incorporated. For example, a non-neighboring group can be replaced with an O atom or an N atom. Suitable functional groups are in particular the urea group -NC-CO-NH-. X is chosen by those skilled in the art according to the desired properties. Particularly suitable polymers usually have a molecular weight of 1000-100000, preferably 1500-50000, particularly preferably 2000-20000 g / mol.

  The cationic polymer V preferably contains different linking groups A ′ and A ″.

  Thus, the groups A 'and A "are preferably arranged alternately, but in principle can be present in the polymer in the desired order and number.

  The group A 'is a group comprising alkylene units and urea units:

Here, k and k ′ are each independently a natural number of 1 to 5, preferably 2 or 3. R ⁶ and R ^{6 ′} are, independently of one another, H or a linear or branched alkyl group of 1 to 12 carbon atoms. R ⁶ and R ^{6 ′} are preferably selected from the group consisting of H, —CH ₃ and —C ₂ H ₅ , and R ⁶ and R ^{6 ′} are particularly preferably H.

  The group A "is a linear or branched alkylene group of 2 to 20 carbon atoms. This group may be substituted by a group such as -OH or = O. Carbon atoms that may not be substituted with one or more identical or different heteroatoms, such as O, S and / or N. O-substituents are preferred.

  A "is the formula,

(However, l is a natural number of 1 to 3). A ″ is particularly preferably —CH ₂ CH ₂ —O—CH ₂ —CH ₂ —.

  The production method and characteristics of such cationic polymers and cationic polymers are known in principle, and are particularly known as hair cosmetic compositions. Reference is made, for example, to DE-A 2521960 or DE-A 2924230.

  Formula VI,

のポリマーが特に好ましい。カチオン性ポリマーは、錯化剤と同等の量で使用することが好ましい。当然、錯化剤とカチオン性ポリマーの両方が、酸洗い抑制剤と共に使用されても良い。

The polymer is particularly preferred. The cationic polymer is preferably used in an amount equivalent to the complexing agent. Of course, both complexing agents and cationic polymers may be used with pickling inhibitors.

  The preparation used may also contain other ingredients or auxiliaries depending on the intended use.

  It is advantageous to add a small amount of a water miscible organic solvent to the composition in order to improve the grease removal in the degreasing by pickling. The amount of the organic solvent that is optionally added is usually 0 to 10% by mass. Examples of suitable water miscible solvents include monoalcohols such as methanol, ethanol, or propanol, higher alcohols such as ethylene glycol or polyether polyol, and ether alcohols such as butyl glycol or methoxypropanol.

  Examples of other auxiliaries include, for example, antifoams such as polypropoxylate or silicon ether. The type and amount of additional ingredients or auxiliaries are determined by those skilled in the art according to the intended use. The amount of additional auxiliaries optionally added is usually 0-5% by weight.

  In addition to the components mentioned above, the preparation for phosphorylation includes zinc ions, phosphate ions, and optionally other components such as fluorides, especially complex fluorides, accelerators such as nitrite ions, manganese, copper Metal ions such as magnesium or nickel ions. Acidic preparations for phosphorylation are disclosed, for example, in WO 99/32687, DE-A 19923084 or DE-A 19723084.

  In the novel method, the metal surface is brought into contact with the aqueous preparation, for example by spraying, dipping or rolling. After the dipping process, the workpiece may be drip to remove excess processing solution; however, in the case of a metal sheet, metal foil, or the like, the excess processing solution is, for example, It can be squeeze out.

  It is of course possible to treat the metal surface inside the plant. Internal precipitates in boilers, pipelines or the like can be removed by filling the plant equipment interior with the preparation according to the invention or by flushing with the preparation according to the invention. Dissolution of the precipitate is facilitated by circulating the preparation in the factory equipment with a pump.

  The new method can optionally also include one or more preliminary steps. For example, the metal surface can be cleaned before pickling with the preparation according to the invention, for example to remove grease or oil. This is particularly desirable when phosphorylating.

  Further, the method may optionally include a post-processing step. Examples of these are in particular washing steps in which the treated surface is washed with a suitable washing liquid, in particular water, for example in order to remove residues of the preparation used according to the invention from the surface.

  It is also possible to employ the so-called “no-rinse” method, in which the solution to be handled is applied directly to the drying oven without being washed after being applied.

  The treatment can be performed discontinuously or continuously. The continuous process is particularly suitable for processing strip metal. Here, the metal strip passes through a tank or spray device and optionally to another pre-treatment or post-treatment station.

  The temperature and duration of processing are determined by those skilled in the art depending on the intended use. Higher temperatures on the one hand promote pickling attack on the layer to be dissolved, but on the other hand promote pickling attack on the metal itself as well. Usually, the processing temperature is 20 to 80 ° C., but the present invention is not limited to this range. The duration of the process may be 1 second to several hours. Usually, the duration of the process is shorter when the temperature is high than when the temperature is low.

  For pickling of steel strips, a combination of a temperature of 60-80 ° C., for example 70 ° C., and a contact time of 1-10 seconds has been found to be particularly useful. For the steel strip, pickling solutions containing sulfuric acid or hydrochloric acid are particularly suitable.

  In the novel process, pickling attack on the metal is substantially more strongly suppressed than when a non-alkoxylated pickling inhibitor is used. The complexing agent, in combination with an alkoxylated pickling inhibitor, exhibits synergy and substantially reduces further pickling attack.

  In a preferred embodiment of the invention, the acidic aqueous composition can be used as a fountain solution for offset printing. The ethoxylated alkynol present in the preparation advantageously prevents unwanted corrosion on the printing press and printing plate. Suitable acids for this application are in particular phosphoric acid or organic acids such as, for example, succinic acid, usually as components of the buffer system.

  Conventional additives known to those skilled in the art can be used as separate components for this application. Examples include alcohols such as glycerol, hydrophilic polymers such as gum arabic, or cellulose derivatives, surfactants and biocides.

Examples illustrating the invention Abbreviations used PA: propargyl alcohol BDA: 2-butyne-1,4-diol EO: ethylene oxide PO: propylene oxide PA-nEO: propargyl alcohol PA-nPO ethoxylated with average n ethylene oxide units : Propargyl alcohol BDA-nEO propoxylated with average n propylene oxide units: 2-butyne-1,4-diol BDA-nPO ethoxylated with average n ethylene oxide units: 2 propoxylated with average n propylene oxide units -Butyne-1,4-diol

Production of pickling inhibitors The production of the alkoxylates used for the new process was carried out on the basis of the process disclosed in DE-A 2241155.

  A method for producing an ethylene oxide adduct starting from propargyl alcohol will be described in the form of examples.

Ethoxylated propargyl alcohol (PA-2EO)
In a 6I pressure-resistant reactor with anchor stirrer, temperature control function, and nitrogen inlet, 1200 g of propargyl alcohol, 24 g of triphenylphosphine and 2 equivalents of ethylene oxide or propylene oxide, 12 The reaction was carried out at 55-65 ° C. under a nitrogen atmosphere over the course of time.

Preparations used The following solutions were used for testing.

Detergent solutions 1-3
In each case, a corrosion inhibitor solution (if present) and a complexing agent in water (if present) were prepared. The amounts of corrosion inhibitor and complexing agent are shown in Tables 1 to 4 in each case. The pH was set with acid in each case. In each case, the total amount was 100 g.
Solution 1 Set to pH 3.5 with 15% strength HCl.
Solution 2 Set to pH 1 with concentrated H ₂ SO ₄ .
Solution 3 Set to pH 3.5 with concentrated H ₃ PO ₄ .

Pickling degrease solution 4 1g Pickling inhibitor (according to Table 5)
3 g Nonionic surfactant: saturated C ₁₃ -oxo alcohol, ethoxylated, average 8 EO units 0.2 g Anionic surfactant: acidic phosphate ester of fatty alcohol alkoxylate 50 g Concentrated HCl (37% HCl)
45.8g Water Water content: 77.3%
Water + acid content: 95.8%
Solution 4a 0.2% by weight methyl glycine diacetate (0.2% by weight, less water) for solution 4
Solution 5 1 g Pickling inhibitor (according to Table 5)
3 g Nonionic surfactant: saturated C ₁₃ -oxo alcohol, ethoxylated, average 8 EO units 3 g 3-nitrobenzenesulfonic acid 0.5 g alkylphenol ether sulfate, Na salt, 40% concentration 50 g concentrated HCl (37% HCl)
42.5g Water Water content: 74.3%
Water + acid content: 92.8%
Solution 6 2 g Pickling inhibitor (according to Table 5)
0.5 g Nonionic surfactant: oleylamine, ethoxylated, average 12 EO units 0.5 g Nonionic surfactant: Saturated C ₁₃ -oxo alcohol, ethoxylated, average 8 EO units 25 g Concentrated H ₂ SO ₄ (96% )
72g Water Water content: 73%
Water + acid content: 97%
Acid rust remover solution 7 1g Pickling inhibitor (according to Table 5)
12 g Nonionic surfactant: saturated C _13-15 -oxo alcohol, ethoxylated, average 8 EO units 5 g dodecylbenzenesulfonic acid 40 g concentrated H ₃ PO ₄ (85%)
42g Water Water content: 48%
Water + acid content: 82%
Solution 7a For solution 7, 0.2% by weight methyl glycine diacetate (0.2% by weight, less water)
Acid detergent solution 8 5g Pickling inhibitor (according to Table 5)
8 g Nonionic activator: saturated C ₁₃ -oxo alcohol, ethoxylated, average 12 EO units 50 g concentrated H ₃ PO ₄ (85%)
37g Water Water content 44.5%
Water + acid content 87%

Polymeric complexing agent and cationic polymer as additive In each case, a 0.5% strength solution of corrosion inhibitor (if present) and a 0.25% strength solution of complexing agent in water (present) Case). In each case, the total amount was 100 g.
Solution 9 0.5 g pickling inhibitor
Set to pH 1 with concentrated H ₂ SO ₄
And 50 g / l Fe (II) sulfate in solution 10 for solution 9 and additionally 0.25% by weight of methylglycine diacetate solution 11 for solution 9 and additionally 0.25% by weight of polymer complex. Agent (modified with polyethyleneimine, acetate group, Na salt)
Solution 12 For solution 9, an additional 0.25% by weight formula,

で表される、カチオン性ポリマー

Cationic polymer represented by

Normal experimental method Measuring principle:
A defined test sheet of St 1.0037, Al 99.9 or Zn 99.8 is immersed in a certain test solution (solutions 1-7, see page 1) at room temperature for 1-24 hours, and mass loss per unit area Was determined by gravimetry weighing the mass difference.

  The manufacture and cleaning of the metal sheet was carried out according to the material-specific manner of ISO 8407 material, and St 1.0037 was specifically described here.

2. Preparation of metal sheet Degreasing: In a plastic tank with two sheet-like electrodes (stainless steel or graphite) larger than the test sheet, a solution of a degreasing bath having the following composition was used:
20 g NaOH
22 g Na ₂ CO ₃
16 g Na ₃ PO ₄ .12H ₂ O
1g ethylenediaminetetraacetic acid (EDTA)
0.5 g of nonionic surfactant: alkylphenol, ethoxylated, average EO units of about 940 ml deionized water NaOH, Na ₂ CO ₃ and Na ₃ PO ₄ are continuously dissolved in deionized water with stirring did. At the same time, EDTA and a surfactant were separately preliminarily dissolved in deionized water. This preliminary dissolution was performed at a temperature of 50 ° C. in the case of a surfactant. Next, in a measuring cylinder, the EDTA and surfactant solution was added to sodium hydroxide and, after cooling, made up to 1000 ml with deionized water.

  Rust removal: In a plastic tank with two sheet-like electrodes larger than the test sheet, a rust removal bath solution having the following composition was used: 100 g diammonium citrate in 1000 ml deionized water .

  Steel sheets with dimensions 50 mm × 20 mm × 1 mm were wiped with a paper cloth and dipped between 10 volt electrodes of a degreasing bath and connected as a cathode. The voltage was adjusted so that the current was 1A. After 10 seconds, the steel sheet was removed and washed with running water for 5 seconds.

A steel sheet was dipped between the 10 volt electrodes of the rust removal bath and connected as a cathode. The voltage was adjusted so that the current was 1A. After 3 minutes, the steel sheet was removed, washed with deionized water (running water) for 5 seconds, blown with air, and used directly for testing.
3. Pickling test A metal sheet having dimensions of 50 mm × 20 mm × 1 mm was electrically degreased and derusted.

  The initial mass was determined from the analytical balance. After weighing, the metal sheet was used directly. The manufactured metal sheet was diagonally arranged in a 200 ml glass bottle containing the test solution. The angle between the steel sheet and the foundation was 35 °. The glass bottle was tightly closed at room temperature and stored at room temperature. During storage, the glass bottle was simply shaken once every 6 hours.

  The metal sheet was removed from the solution, washed with deionized water, brushed with steel wool, washed with deionized water, and dried by blowing air. Next, the mass was measured.

  A gravimetric pickling test was performed as 10 measurements and the average value was calculated.

Simultaneously with this test, no pickling inhibitor was used, and but-2-yne-1,4-diol or propargyl alcohol was used as a pickling inhibitor, Ten measurements were taken.
4). Evaluation of results The difference between the first and second measurements in mg / cm ² was recorded for each metal sheet (Δm _Sample ). In addition to this, the efficiency E of the active substance is displayed. The efficiency E is the mass loss Δm _Sample expressed in relation to the mass loss Δm ₀ in the corrosion test without using the inhibitor. The following applies:

  According to this equation, the maximum suppression efficiency is 1 (no metal removal), 0 (deionized water), but also <0 if the introduction of the additive promotes corrosion.

Examples Tests without using complexing agents Examples 1-8, Comparative Examples 1-3
Solution 1 was used for testing (HCl, pH 3.5). With respect to the steel 1.0037 sheet, the metal removal amount per unit area and the suppression efficiency E at 30 ° C. after 1 hour and 24 hours were measured according to the above-described method. The pickling inhibitors shown in Table 1 were used in the indicated amounts. In these tests, no complexing agent was present. The results are summarized in Table 1.

Examples 9 and 10, Comparative Examples 4 and 5
Solution 2 was used for the test (H ₂ SO ₄ , pH 1). With respect to the steel 1.0037 sheet, the metal removal amount per unit area and the suppression efficiency E at 30 ° C. after 1 hour and 24 hours were measured according to the above-described method. The pickling inhibitors shown in Table 2 were used in the indicated amounts. In these tests, no complexing agent was present. The results are summarized in Table 2.

Synergistic mixing with complexing agents Examples 11-18, Comparative Examples 6 and 7
Solution 1 was used for testing (HCl, pH 3.5). For steel 1.0037 sheets, the inhibition efficiency E at room temperature for 1 hour was measured generally according to the method described above. The pickling inhibitors and complexing agents shown in Table 3 were used in the indicated amounts. The results are summarized in Table 3.

Examples 19-30, Comparative Examples 8-10
Solution 3 was used for testing (HCl, pH 3.5). For steel 1.0037 sheets, the inhibition efficiency E at room temperature for 1 hour was measured generally according to the method described above. The pickling inhibitors and complexing agents shown in Table 4 were used in the indicated amounts. The results are summarized in Table 4.

Examples 31-42, Comparative Examples 11-15
Solutions 4-8 were used for testing (see above). For steel 1.0037 sheets, the inhibition efficiency E at room temperature for 1 hour was measured generally according to the method described above. The pickling inhibitors and complexing agents shown in Table 5 were used in the indicated amounts. The results are summarized in Table 5.

  The examples show that the alkoxylated pickling inhibitors used according to the present invention are much more effective than propargyl alcohol or butynediol. Thus, not only provides an ecologically safer alternative, but also provides an alternative that has a better effect. This applies in particular to steel surfaces.

Furthermore, it was surprising that they cooperate synergistically with complexing agents. When the complexing agent is used alone, the metal dissolution is promoted. On the other hand, the combination of the complexing agent and the pickling inhibitor has a greater inhibitory effect than when the pickling inhibitor is used alone.

Claims (13)

In a method of pickling a metal surface by treating the metal surface with an acidic aqueous preparation comprising at least one acid, a pickling inhibitor, and optionally another additive,
An aqueous preparation comprising at least the following components:
(A) 60-99.99% by weight of a mixture of water and at least one acid,
(B) 0.01-2% by weight of the formula,

Wherein the radicals R ¹ are each independently H or methyl in each case and the indices n and n ′ are independently 1 to 10). Alkyne alkoxylate,
(C) 0 to 38% by weight of one or more additives and / or auxiliaries,
A method comprising the steps of:   The method of claim 1, wherein the indices n and n 'are 1 to 3 independently of each other.   The method according to claim 1, wherein the composition further comprises 0.01 to 20% by mass of at least one surfactant.   The composition further comprises 0.01 to 10% by weight of at least one, at least bidentate, water-soluble chelating complexing agent, and the chelating complexing agent comprises an acidic group. The method according to any one of claims 1 to 3.   The method according to claim 4, wherein the ratio of the complexing agent to the pickling inhibitor is 5: 1 to 1:10.   The method according to any one of claims 1 to 3, wherein the composition further comprises 0.01 to 10% by mass of at least one water-soluble polymer, and the water-soluble polymer comprises a quaternary ammonium group. .   The method according to any one of claims 1 to 6, wherein the amounts of water and acid are 70 to 99.99% by mass.   The method according to any one of claims 1 to 7, wherein the pH of the composition is 3 to 6.   The method according to any one of claims 1 to 8, wherein the acid is at least one acid selected from the group consisting of hydrochloric acid, sulfuric acid, methanesulfonic acid, and phosphoric acid.   The method according to any one of claims 1 to 9, wherein the metal surface is a surface of iron, steel, zinc, brass or aluminum.   11. A method according to any preceding claim, wherein the surface is a strip metal surface. An acidic aqueous composition for pickling metal surfaces comprising at least one acid, a pickling inhibitor, and optionally another additive, the aqueous preparation comprising at least the following components:
(A) 60 to 99.97% by weight of a mixture of water and at least one acid,
(B) 0.01-2% by weight of the formula,

Wherein the group R ¹ is, in each case, independently of each other, H or methyl, and the indices n and n ′ are independently of each other 1-10. Seeds of alkyne alkoxylates,
(C) 0.01-20% by weight of at least one surfactant, and
(D) 0.01-10% by weight of at least one water-soluble chelating complexing agent containing at least one acidic group and / or a water-soluble polymer containing at least one quaternary ammonium group,
An acidic aqueous composition for pickling a metal surface characterized by comprising: An aqueous preparation having at least the following composition:
(A) 70-98.9% by weight of a mixture of water and at least one acid,
(B) 0.1-2% by weight alkyne alkoxylate,
(C) 0.5 to 15% by weight of a surfactant, and (d) 0.5 to 10% by weight of a chelate-forming complexing agent and / or a water-soluble polymer containing a quaternary ammonium group,
The composition according to claim 12, comprising: