JP2000096049A - Corrosion inhibitor for acid cleaning of metal, cleaning liquid composition containing the same, and cleaning of metal by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a corrosion inhibitor for acid cleaning of a metal, capable of efficiently inhibiting the corrosion of the metal, hardly causing local corrosion, providing high whiteness after cleaning, when the metal is subjected to the acid cleaning, and useful for an iron and steel-producing process or the like by including a specific polyamine compound. SOLUTION: This corrosion inhibitor comprises a polyamine compound of formulas I or II (R1 and R2 are each H, methyl, ethyl, propyl, hydroxyethyl, benzyl or dodecylbenzyl; X is a halogen or HSO4). Preferably, the cleaning composition is prepared by adding 0.1-50,000 mg polyamine compound of formulas I or II, and the cleaning of the metal is carried out by spraying the obtained cleaning composition on the surface of the metal, or dipping the surface of the metal into the cleaning composition to clean the metal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal corrosion inhibitor for acid cleaning added to an acid cleaning solution used for removing scale and rust on a metal surface, and more particularly to hydrochloric acid, sulfuric acid and organic acid cleaning solutions. The present invention relates to an effective corrosion inhibitor, an acid cleaning liquid composition to which the corrosion inhibitor is added, and an acid cleaning method using the acid cleaning liquid composition.

[0002] The present invention further relates to a corrosion inhibitor effective for use in a continuous pickling process of hot-rolled steel sheet with hydrochloric acid in a steel production process, a cleaning liquid composition containing the same, and a method for cleaning metals using the same.

[0003]

2. Description of the Related Art Conventionally, a scale formed on a heat exchanger or a paper digester for removing rust attached to a metal or an oxide film such as a scale formed on a metal surface during hot rolling. An inorganic acid such as hydrochloric acid or sulfuric acid, an organic acid such as oxalic acid or citric acid, or a chelating agent such as ethylenediaminetetraacetic acid has been used to remove these.

However, the use of the cleaning solution alone not only removes rust, hot-rolled scale, calcium scale, etc., but also causes corrosion of the metal substrate, so that it is necessary to use a corrosion inhibitor in combination.

Various corrosion inhibitors have been used for this purpose, such as thiourea derivatives such as diethyl urea and dibutyl thiourea, organic sulfur compounds such as benzothiazole, primary, secondary and tertiary amines. And the like are known. JP-A-61-37988 discloses an additive containing a quaternary ammonium salt.

On the other hand, in a continuous pickling process for steel sheets in a steel production process, hydrochloric acid is generally used as an acid cleaning solution, and in such a process, there is a demand that the steel sheet is less corroded and the pickling rate is high. It is required that the appearance of the steel sheet be not degraded, such as blackening of the color tone. Therefore, there is a need for a corrosion inhibitor to be added to an acid cleaning solution that is more suitable from the viewpoints of process rationalization and aesthetic appearance of the steel sheet surface.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above problems, and in particular, improves the acid cleaning speed in the acid cleaning process of a steel sheet, and effectively suppresses the corrosion of the steel sheet substrate. Further, it is an object of the present invention to provide a corrosion inhibitor which does not impair the aesthetic appearance of a substrate, a cleaning liquid composition containing the same, and a method for cleaning a metal using the same.

[0008]

According to the present invention, there is provided a compound of formula (3)
Or a corrosion inhibitor for pickling a metal, which comprises a polyamine compound represented by Chemical formula 4.

[0009]

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[0010]

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R1 and R2 are the same or different from each other and include hydrogen, methyl, ethyl, propyl,
X is Cl, a group selected from the group consisting of a hydroxyethyl group, a benzyl group and a dodecylbenzyl group.
Shows Br, I, F or HSO4.

The corrosion inhibitor for pickling a metal according to the present invention is a polyamine compound represented by Chemical Formula 3 and / or Chemical Formula 4. Although the corrosion inhibition mechanism of the corrosion inhibitor of the present invention has not been sufficiently elucidated, it is adsorbed on both the anode and cathode sites formed on the surface of the metal substrate in the cleaning solution, and the protective film is uniformly applied to the entire surface of the metal substrate. Is considered to be due to the formation of

Further, the present invention is characterized in that both R1 and R2 are hydrogen and X is Cl.

According to the invention, R1 and R2 are both hydrogen and X is Cl. This is particularly preferable because of its excellent corrosion inhibiting effect.

In the present invention, the polyamine compound according to claim 1 or 2 may be used in an amount of 0.1 to 50,000 m / L of the acid solution.
A cleaning liquid composition comprising g.

According to the present invention, chemical formula 3 and / or chemical formula 4
0.1 to 50,000 m per 1 L of an aqueous solution of an inorganic acid, an organic acid or a chelating agent
By adding g, preferably 1 to 1000 mg, the corrosion of the metal substrate can be effectively suppressed and the metal substrate can be washed.

The target inorganic acid is one or more of hydrochloric acid, sulfuric acid, phosphoric acid, sulfamic acid, hydrofluoric acid or nitric acid, and the organic acid is formic acid, acetic acid, oxalic acid, citric acid, tartaric acid, malic acid, hydroxyacetic acid. Alternatively, it is at least one kind of gluconic acid, and examples of the chelating agent include ethylenediaminetetraacetic acid (including an alkali metal salt and an ammonium salt).

When the amount of the corrosion inhibitor added is 0.1 mg or less per 1 L of the cleaning solution, no corrosion inhibitory effect is obtained.
Addition of 000 mg (50 g) or more does not increase the corrosion inhibiting effect.

The corrosion inhibitor of the present invention may be added to the pickling solution at the time of use, or may be added to the pickling solution in advance to form a cleaning solution composition, and used as it is or diluted with water. Further, a surfactant or a solvent may be used to improve the mixing with the cleaning liquid, and the surfactant or the solvent used for this may be previously mixed with the corrosion inhibitor of the present invention, or separately. It may be added to the cleaning agent.

Further, the corrosion inhibitor of the present invention may be used in combination with other corrosion inhibitors, and these other corrosion inhibitors may be mixed with the corrosion inhibitor of the present invention in advance and separately washed. It may be added to the agent.

Specific examples of other corrosion inhibitors used in combination include triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexamethylenetetramine, 2-propyn-1-ol, 1-hexyne-3-ol.
All, 4-ethyl-1-octin-3-ol, 1-
Butynediol, 3-methyl-1-pentyn-3-ol, 3-methyl-1-butyn-3-ol, 2,5-dimethyl-3-hexyne-2,5-diol, thiourea,
Thiosemicarbazide, phenylthiourea, tolylthiourea, N-methylthiourea, dimethylthiourea, diethylthiourea, dibutylthiourea, tetramethylthiourea,
Methylisothiourea, benzylisothiourea, diisopropylthiourea, ethylenethiourea, mercaptobenzothiazole, 2,5-dimercapto1,3,4-thiadiazole, 2-mercaptobezothiazole, 2- (thiocyanomethylthio) benzothiazole, -(2-benzothiazylthio) propionic acid, (2-benzothiazylthio) acetic acid, 2-mercaptoimidazolineethylenethiourea, isobutylmercaptan, butylmercaptan,
Octyl mercaptan, mercaptobenzothiazyl sulfide, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, dibenzyl sulfoxide, 1-hydroxy-1-ethyl-2-stearyl imidazolium ethosulfate, 1-dodecyl-2-methyl- 3-benzylimidazolium chloride, 1-benzyl-2-phenylimidazolium chloride, 2-undecyl-1-hydroxyethyl-1-benzylimidazolium salt, 2-aviethyl-1-hydroxyethyl-
1-benzylimidazolium salt, 1,8-bis (1-hydroxyethyl-1-benzylimidazolium salt) 2,
2 'octane, 2-undecyl glyoxaridium ethyl sulfate, alkylpyridinium chloride, alkylpicolinium chloride, alkylpyridinium bromide, alkylpicolinium bromide, alkylpyridinium iodide, alkylpicolinium iodide, N- (p-chlorobenzyl ) -Pyridinium chloride, N- (p-chlorobenzyl) -picolinium chloride, laurylquinolinium chloride, alkylisoquinolinium chloride, alkylisoquinolinium bromide, benzylpyridinium chloride, N-hydroxyethyl-picolinium chloride ,
Benzylpicolinium chloride, N-hydroxyethyl-pyridinium chloride, N-hydroxyethyl-
Picolinium chloride, N- (p-laurylbenzyl) -pyridinium chloride, N- (p-laurylbenzyl) -picolinium chloride, N-carboxymethylpyridinium chloride, N-carboxymethylpicolinium chloride, N-carbamoylethyl- Pyridinium chloride, N-carbamoyl picolinium chloride, N-hydroxyethoxyethyl-pyridinium chloride, N-hydroxyethoxyethyl-picolinium chloride, N-allyl-pyridinium chloride, N-allyl-picolinium chloride, dodecylbenzyl-4- Picolinium chloride, trimethylbenzylammonium chloride, N-benzyl (3,5-
Rutidinium) chloride, N-lauryl (3,5-rutidinium) chloride, and the like, but are not limited to these specific examples.

Further, in the present invention, a pickling accelerator for improving the pickling speed can be used in combination. That is, sulfites, thiosulfates, sodium hydrosulfite, calcium hydrosulfite, sodium sulfide, ammonium sulfide, ammonium bisulfite, sodium bisulfite, and rhodan ammonium as acid pickling accelerators combined with the corrosion inhibitor of the present invention. And at least one organic sulfur compound selected from the group consisting of thioglycolic acid, ammonium thioglycolate, sodium thioglycolate, 2-ethylhexyl thioglycolate, methoxybutyl thioglycolate, and trimethylolpropane tris (thiol). Glycolate), thioglycerol, thioacetic acid, thiodiglycol, 3,3-thiodipropionic acid, thiophenol, benzyl mercaptan,
Thiobenzoic acid, thiosalicylic acid, 2-aminothiophenol, 2-mercaptoimidazoline, 2-mercaptoethanol, mercaptopropionic acid, β-mercaptopropionic acid, 3-methoxybutyl β-mercaptopropionate, trimethylolpropane tris (β -Thiopropionate), 2-ethylhexyl β-mercaptopropionate, 2-mercaptobenzothiazole, triglycoldimercaptan, pentaerythritol tetrathioglycolate, 2,4,6-trimercapto-s-
Triazine, pentaerythritol tetrakisthioglycolate, 3,3-dithiodipropionic acid, 2,2-dithiodiethanol, ethylene glycol dithioglycolate, thiodiglycolic acid, thioacetamide, thiourea dioxide, allyl isothiocyanate, p-toluene Sodium sulfonate, glyoxal sodium bisulfite, guanylthiourea, thiolactic acid, thiomalic acid, 2-
Mercaptobutyric acid, benzyl thiocyanate, dimethyl sulfoxide, sodium diethylthiocarbamate,
p-toluenesulfonhydrazide, methanesulfonic acid,
Butanesulfinic acid, benzenesulfinic acid, toluenesulfinic acid, pyridinesulfinic acid, ammonium benzenesulfinate, ammonium toluenesulfinate, ethyl benzenesulfinate, benzenesulfinyl chloride, N-methylbenzenesulfinylamide, butanesulfenyl chloride, chloride Compounds comprising benzenesulfenyl, pyridinesulfenyl chloride, butanedisulfoxide, benzenesulfoxide, pyridinesulfoxide, butanedisulfone, diphenylsulfone, dipyridinesulfone, benzenesulfinic acid and / or toluenesulfinic acid alkali metal salts or amine salts. Can be

The present invention is also a method for cleaning a metal, comprising spraying the cleaning liquid composition on a metal surface or immersing the metal surface in the cleaning liquid composition to clean the metal surface.

According to the present invention, the cleaning liquid composition containing the corrosion inhibitor of the present invention is sprayed on a metal surface to be cleaned or by immersing a metal piece to be cleaned in the cleaning liquid composition. Is washed. The metal is not particularly limited, but is effective mainly for steel.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described by way of examples.
Although described more specifically, the present invention is not limited to this embodiment.

The measurement of the amount of corrosion, the measurement of the number of pits for evaluating local corrosion, and the measurement of whiteness were carried out by the following methods.

(1) Measurement of Corrosion Amount A cleaning solution aqueous solution containing 100 g of hydrochloric acid, 50 g of ferrous ions and 1 g of ferric ions (hereinafter referred to as an acid cleaning solution) 1
A predetermined amount of a corrosion inhibitor (polyamine compound shown in Chemical formula 3 or Chemical formula 4) is added to L, and the solution is heated to 80 ° C.
A hot-rolled steel plate (JISG 3131) polished with a water-resistant abrasive paper No. 180 was immersed for 10 minutes. The amount of corrosion was calculated by the following equation.

[0028]

(Equation 1)

(2) Measurement of Pitting Corrosion A predetermined amount of a corrosion inhibitor (polyamine compound represented by Chemical Formula 3 or Chemical Formula 4) was added to 1 L of the pickling solution, and the solution was heated to 80 ° C. and then hot-rolled. 18 steel plates (JISG 3131)
The material polished with the No. 0 water-resistant abrasive paper was immersed for 10 minutes.

The number of round pits having a diameter of 10 μm or more on the steel surface having a surface area of 1 cm ² was magnified 100 times using an optical microscope, and the number was visually observed.

(3) Whiteness Measurement A predetermined amount of a corrosion inhibitor (polyamine compound represented by Chemical Formula 3 or 4) is added to 1 L of the pickling solution, and the solution is heated to 80 ° C., and then an oxide film is formed. Hot rolled steel sheet (JISG
3131) After immersion and complete removal of iron oxide, the surface after washing and drying was measured with a colorimeter.

The whiteness was determined by the following colors. Whiteness = 100 − {(100−L) ² + a ² + b ² } ^1/2 where L indicates lightness, a indicates red to green hue, and b indicates yellow to blue tone.

[0033]

Example 1 A polyamine compound represented by Chemical Formula 5 was used as a corrosion inhibitor, and 100 mg was added to 1 L of the same aqueous washing solution as described above, and the amount of corrosion, the number of pits and the whiteness were measured by the methods described above. . Table 1 shows the results.

[0034]

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[0035]

Example 2 The amount of corrosion, the number of pits and the whiteness were measured in the same manner as in Example 1 except that a polyamine compound represented by Chemical Formula 6 was used as a corrosion inhibitor and 100 mg was added as an addition amount. Table 1 shows the results.

[0036]

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[0037]

Example 3 A polyamine compound represented by Chemical Formula 7 was used as a corrosion inhibitor, and 50 mg was added to 1 L of the same aqueous washing solution as described above, and the amount of corrosion, the number of pits,
The whiteness was measured. Table 1 shows the results.

[0038]

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[0039]

Example 4 A polyamine compound represented by Chemical formula 8 was used as a corrosion inhibitor, and 100 mg was added to 1 L of the same aqueous washing solution as described above, and the amount of corrosion, the number of pits, and the whiteness were measured by the methods described above. . Table 1 shows the results.

[0040]

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[0041]

COMPARATIVE EXAMPLE The amount of corrosion, the number of pits and the whiteness were measured in the same manner as in Example 1 except that no corrosion inhibitor was added. Table 1 shows the results.

[0042]

[Table 1]

[0043]

As described above, when a metal is pickled with a cleaning solution composition containing a corrosion inhibitor for pickling a metal according to the present invention, corrosion of the metal is effectively suppressed, there is no local corrosion, and after cleaning, Its whiteness is high, and its industrial value is extremely high.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C23F 11/16 C23F 11/16 11/173 11/173 C23G 1/06 C23G 1/06 F term (Reference) 4H025 AA12 AA22 AA32. DA05 FA12 GA01

Claims (4)

[Claims] 1. A corrosion inhibitor for pickling a metal, comprising a polyamine compound represented by Chemical Formula 1 and / or Chemical Formula 2. Embedded image Embedded image R1 and R2 are the same or different groups,
A group selected from the group consisting of hydrogen, methyl group, ethyl group, propyl group, hydroxyethyl group, benzyl group and dodecylbenzyl group, wherein X is Cl, Br, I, F
Or HSO4. 2. The corrosion inhibitor for metal pickling according to claim 1, wherein both R1 and R2 are hydrogen and X is Cl. 3. A cleaning solution composition comprising 0.1 to 50,000 mg of the polyamine compound according to claim 1 per 1 L of an acid solution. 4. A method for cleaning a metal, comprising spraying the cleaning liquid composition according to claim 3 onto a metal surface or immersing the metal surface in the cleaning liquid composition.