JP2000038689A - Corrosion inhibitor for acid cleaning of metal, cleaning solution composition containing the same and method for cleaning of metal using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively suppress the corrosion of a metal substrate during cleaning and to enhance whiteness after cleaning by using at least one selected from quinolinium compounds and isoquinolinium compounds obtained by quarternizing quinoline compounds and isoquinoline compounds. SOLUTION: At least one selected from quinolinium compounds and isoquinolinium compounds obtained by quarternizing quinoline compounds of formula I and isoquinoline compounds of formula II using a quarternizing agent is used as a corrosion inhibitor for acid cleaning of metals. In formulas I and II, R1-R7 are each H or 1-10C alkyl group which may be a branched alkyl. At least one compound of R8X (R8 is H, hydroxyethyl, benzyl or 1-20C alkyl which may be a branched alkyl; X is Cl, Br, I, F or R8SO4) is used as a quarternizing agent. A corrosion inhibitor is added in an amount of about 0.1-50,000 mg to 1L of an acid solution.

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]

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 a cleaning solution alone not only removes rust, hot-rolled scale, calcium scale, etc., but also causes corrosion of a 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.

[0005] In general, rust, hot-rolled scale, calcium scale, and the like attached to a metal surface have a low dissolution rate in an acid aqueous solution such as an inorganic acid or an organic acid or a chelating agent such as ethylenediaminetetraacetic acid, resulting in low work efficiency.
Cleaning is performed by increasing the temperature of the cleaning solution to increase the dissolution rate.

However, under severe conditions such as increasing the temperature of the cleaning liquid, the dissolution rate of the metal base becomes extremely high, and the conventional corrosion inhibitor cannot provide a sufficient effect.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is directed to a corrosion inhibitor which effectively suppresses corrosion of a metal substrate during cleaning, a cleaning solution composition containing the same, and a cleaning solution containing the same. It is an object of the present invention to provide a method for cleaning a metal using the same.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a quinolinium compound represented by the formula (3) and an quinolinium compound obtained by quaternizing an isoquinoline compound represented by the formula (4) with a quaternizing agent. It is a metal corrosion inhibitor for pickling metals.

[0009]

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[0010]

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R1, R2, R3, R4, R5, R6, R
7 represents a hydrogen atom or an alkyl group which may have 1 to 10 carbon atoms and may be branched;

The corrosion inhibitor for pickling metals according to the present invention is a quinolinium compound represented by Chemical Formula 5 or 6 obtained by quaternizing a quinoline compound represented by Chemical Formula 3 or 4 and an isoquinoline compound by a quaternizing agent. And isoquinolinium compounds.

[0013]

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[0014]

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Here, R1 to R7 are the same as in Chemical formulas 3 and 4, and R8 is a hydrogen atom, a hydroxyethyl group, a benzyl group or an alkyl group having 1 to 20 carbon atoms which may be branched. Is F, Cl, Br, I or R8SO
₄

Although the corrosion inhibiting mechanism of the corrosion inhibitor of the present invention has not been sufficiently elucidated yet, of the anode portion and the cathode portion formed on the surface of the metal substrate in the cleaning solution, the corrosion is mainly caused by adsorption to the cathode portion. It is thought that it suppresses.

The effect of the quaternization is not clear, but the corrosion inhibitory effect is caused by factors such as an increase in solubility in an aqueous solution, adsorption and desorption to a metal substrate, and desorption to a metal surface oxide. It is thought that the effect of promoting localization and suppressing local corrosion and improving the glossiness of the acid-cleaning surface are exhibited. These are a quinoline compound and an isoquinoline compound represented by Chemical Formulas 3 and 4 and a specific 4
The combination of the grading agents is important.

In the present invention, the quaternizing agent is preferably R8X (R8 is a hydrogen atom, a hydroxyethyl group, a benzyl group or an alkyl group having 1 to 20 carbon atoms which may be branched, and X is Cl, Br, I, F or R8SO4).

The present invention also relates to the present invention, wherein R8 of R8X has 8 to 8 carbon atoms.
20 hagellonated alkyls.

According to the present invention, the quinoline compound and the isoquinoline compound represented by the formulas (3) and (4) are
By quaternizing with a grading agent, solubility in water increases, local corrosion is suppressed by uniform corrosion, and the glossiness of the surface of a steel plate or the like after pickling is improved. The quaternized quinolium compound and isoquinolium compound thus obtained include alkyl isoquinolium chloride, alkyl quinolium chloride, alkyl isoquinolium bromide, alkyl quinolium bromide, alkyl isoquinolium iodide, alkyl quinolium ion Dide, benzyl isoquinolium chloride, benzyl isoquinolium chloride, benzyl isoquinolium bromide, benzyl quinolium bromide, benzyl isoquinolium iodide, benzyl quinolium iodide and the like can be mentioned.

Here, the alkyl group has 8 to 20 carbon atoms.
Are preferred, and particularly preferred are those having 8 carbon atoms.
To 18 alkyl groups.

In the present invention, 1 to 1 L of the acid solution is claimed.
The compound obtained by quaternization according to any one of the above (3) is added to 0.1.
A cleaning liquid composition comprising 1 mg to 50,000 mg.

According to the present invention, at least one selected from a quaternized quinoline compound and an isoquinoline compound is used in an amount of 0.1 to 50,000 mg, preferably 1 to 1 L, per liter of an aqueous solution of an inorganic acid, an organic acid or a chelating agent. ~ 100
By adding 0 mg, the corrosion of the metal substrate can be effectively suppressed and the metal substrate can be washed.

The target inorganic acid is at least one 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 a cleaning solution at the time of use, or may be added to a cleaning solution in advance to form a cleaning solution composition, and used as it is or diluted with water. It can also be used by mixing it with a conventional cleaning solution and adjusting the concentration 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.

The corrosion inhibitor of the present invention may be used in combination with another corrosion inhibitor. These other corrosion inhibitors may be mixed with the corrosion inhibitor of the present invention in advance, and may be 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-mercaptobenzothiazole, 2- (thiocyanomethylthio) benzothiazole, 3- (2-benzothiazylthio) propionic acid, (2-benzothiazylthio) acetic acid, 2-mercaptoimidazoline ethylenethiourea, isobutyl mercaptan, butyl mercaptan, octyl mercaptan, mercaptobenzothiazyl sulfide, tetramethylthiuram monosulfide, Tetramethylthiuram disulfide, dibenzyl sulfoxide, 2-undecylglyoxaridium ethyl sulfate, 1-hydroxy-1-ethyl-2-stearyl imidazolium salt 1-dodecyl-2-methyl-3-
Benzylimidazolium salt, 1-benzyl-2-phenylimidazolium salt, 2-undecyl-1-hydroxyethyl-1-benzylimidazolium salt, 2-aviethyl-1-hydroxyethyl-1-benzylimidazolium salt, 1, 8-bis (1-hydroxy-1-benzylimidazolium salt) -2,2'octane, polyamine compound (for example, trade name PAS, polyallylamine (Nitto Boseki), trade name Gascamine 328 (Mitsubishi Gas Chemical), trade name Chemistat) 6300H (Sanyo Kasei), trade name Anilix (Mitsui Chemicals)) and the like, but are not limited to these specific examples.

Further, in the present invention, an acid 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 also provides a method for cleaning a metal, comprising spraying the cleaning solution composition on a metal surface or immersing the metal surface in the cleaning solution 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 piece of metal to be cleaned in the cleaning liquid composition. Is washed. The metal is not particularly limited, but is effective mainly for steel.

[0032]

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 the local corrosion, and the measurement of the 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 (a quaternized quinoline compound or an isoquinoline compound) is added to L, and the solution is heated to 80 ° C., and then a hot-rolled steel sheet (JIS G 3131) is added to L.
What was polished with water-resistant abrasive paper No. 80 was immersed for 10 minutes. The amount of corrosion was calculated by the following equation.

[0035]

(Equation 1)

(2) Measurement of Pitting Corrosion Number A predetermined amount of a corrosion inhibitor (quaternized quinoline compound or isoquinoline compound) was added to 1 L of the pickling solution, and the solution was heated to 80 ° C. and then hot-rolled. Steel plate (JISG313
1) was polished with a # 180 water-resistant abrasive paper and 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 measured.

(3) Measurement of Whiteness A predetermined amount of a corrosion inhibitor (quaternized quinoline compound or isoquinoline compound) was added to 1 L of the pickling solution, and the solution was heated to 80 ° C. After immersion in a hot-rolled steel sheet (JIS G 3131) to completely remove 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.

[0040]

Example 1 Undecylquinolinium chloride 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.

[0041]

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 undecylisoquinolinium chloride was used as a corrosion inhibitor and 100 mg was added as an addition amount. Table 1 shows the results.

[0042]

Example 3 1 L of an aqueous solution of the same cleaning solution as above using pentadecylquinolinium bromide as a corrosion inhibitor
And the amount of corrosion, the number of pits, and the whiteness were measured by the methods described above. Table 1 shows the results.

[0043]

Example 4 Using benzyl isoquinolinium chloride as a corrosion inhibitor, 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.

[0044]

[Comparative Example 1] No corrosion inhibitor was added, and the others were as in Example 1.
The amount of corrosion, the number of pits, and the whiteness were measured in the same manner as described above. Table 1 shows the results.

[0045]

Comparative Example 2 Example 1 was repeated except that undecylquinoline, a compound before quaternization of the corrosion inhibitor described in Example 1, was used as the corrosion inhibitor, and 100 mg was added as an addition amount.
The amount of corrosion, the number of pits, and the whiteness were measured in the same manner as described above. Table 1 shows the results.

[0046]

Comparative Example 3 Corrosion was performed in the same manner as in Example 1 except that undecylisoquinoline, a compound before quaternization of the corrosion inhibitor described in Example 2, was used as the corrosion inhibitor and 100 mg was added as an addition amount. The amount, pitting number and whiteness were measured.
Table 1 shows the results.

[0047]

[Table 1]

[0048]

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.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazushi Fujiwara F-term (reference) 4H025 AA12 AA22 AA32 AA42 AA54 AA56 AA91 AC05 4K053 QA01 in Asahi Chemical Industry Co., Ltd. RA14 RA15 RA16 RA17 RA18 RA19 RA45 RA46 RA47 4K062 AA03 BB04 BB12 BB18 BB21 CA05 GA10

Claims (5)

[Claims] 1. A quinoline compound represented by the formula 1 and an isoquinoline compound represented by the formula 2
A corrosion inhibitor for pickling metals, comprising at least one of a quinolinium compound and an isoquinolinium compound obtained by grading. Embedded image Embedded image R1, R2, R3, R4, R5, R6, and R7 each represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms which may be branched. 2. The quaternizing agent is R8X (R8 is a hydrogen atom, a hydroxyethyl group, a benzyl group or a group having 1 to 20 carbon atoms.
Represents an optionally branched alkyl group, and X represents Cl, Br,
Indicates I, F or R8SO4. 2. The corrosion inhibitor for acid cleaning according to claim 1, wherein the corrosion inhibitor is at least one of the following. 3. The corrosion inhibitor for acid washing according to claim 2, wherein R8 of R8X is alkyl hagellon having 8 to 20 carbon atoms. 4. The compound obtained by quaternizing according to claim 1 in an amount of 0.1 mg to 50 L per 1 L of the acid solution.
A cleaning liquid composition comprising 000 mg. 5. A method for cleaning a metal, comprising spraying the cleaning liquid composition according to claim 4 on a metal surface or immersing the metal surface in the cleaning liquid composition to clean the metal surface.