JP2014205885A - Yellow discoloration inhibitor during acid cleaning of steel material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inhibitor for a steel material inhibiting yellow discoloration of a steel material in a water washing process after hydrochloric acid cleaning, inhibiting corrosion of a steel material, without lowering quality of a surface of the steel material after acid cleaning nor inhibiting a removing speed of an oxide film and a scale attached on the surface of the steel material.SOLUTION: An inhibitor contains 100 pts.wt. of (a) high molecular amine having a molecular weight of 1000 or more, 400 to 1000 pts.wt. of (b) middle molecular amine having the molecular weight of 250 or more and less than 1000, 100 to 200 pts.wt. of (c) low molecular amine having the molecular weight of less than 250, 200 to 1000 pts.wt. of (d) acetylenic alcohol, 100 to 500 pts.wt. of (e) polyether and water.

Description

  The present invention relates to an inhibitor used in removing an oxide film and scale attached to a steel surface, and more specifically, a steel pickling inhibitor having an effect of suppressing yellowing in a water washing step after hydrochloric acid washing, and the inhibitor The present invention relates to an acid cleaning liquid composition added to a hydrochloric acid cleaning liquid, and further to an acid cleaning method using the acid cleaning liquid composition.

Steel is pickled with hydrochloric acid or sulfuric acid at the time of descaling hot rolled steel, but water washing (rinse) is performed to remove the iron salt generated by the reaction with the acid solution and steel attached to the steel. Do.
However, for example, the surface of the steel material is very activated even if it is sufficiently washed at low speed operation or when the line is stopped, and there are acid solutions and iron salts that cannot be removed by washing. By doing so, rust is generated and the surface of the steel material is discolored.
In itself, products with rust not only lose their commercial value, but also suffer from economic loss and deterioration of properties such as breakage and poor plating.

  To prevent this, the descaled steel is washed with warm water and then immediately dried with a dryer, or under conditions where discoloration is likely to occur, such as line stoppage or low-speed operation, the amount of water and water pressure are increased to remain on the steel surface. For example, the acid solution or iron salt is removed as much as possible. In addition, since rust is generated in a short time when exposed to a high humidity environment, a method such as a dry air atmosphere is employed.

  However, these conventional technologies cannot prevent discoloration and rusting of the steel material. For example, in the method of drying with a dryer immediately after washing with warm water, discoloration cannot be sufficiently prevented because acid solution or iron salt remains, and discoloration in the rinsing process in the pickling process of hot rolled steel It is impossible to prevent. In addition, the method of increasing the amount of water and the water pressure during low-speed operation of the line cannot completely remove the acid solution and iron salt, and the surface of the steel material is also activated, causing discoloration. Furthermore, when the line is stopped, the generation of rust cannot be prevented by washing with a large amount of hot water.

  Therefore, a steel material discoloration prevention agent (Patent Document 1) made of cyclohexylamine, a discoloration prevention agent (Patent Document 2) made of a compound having an amino group and the like, and a discoloration prevention agent made of hydrazine (Patent Document 3) have been proposed. Yes. Furthermore, a discoloration inhibitor (Patent Document 4) comprising an aliphatic dicarboxylic acid or a salt thereof, a polymer of an unsaturated carboxylic acid or a salt thereof, and an amine compound has been proposed.

JP-A-1-225785 Japanese Patent Publication No.7-835 JP-A-2-12587 JP-A-3-24098

  However, these methods using an amine compound such as cyclohexylamine, hydrazine, aliphatic dicarboxylic acid or a salt thereof, a polymer of unsaturated carboxylic acid or a salt thereof, and an amine compound as a discoloration inhibitor can provide a certain effect. However, there is a way to increase the amount of use because it is not sufficient, but it is not economical.

  In recent years, the use of the compounds used for the anti-discoloring agent is particularly undesirable because of the problem of environmental pollution, because it has a bad influence on the human body and the environment and the COD load of factory waste water is large.

  The purpose of the present invention is to suppress yellowing in the water washing step after hydrochloric acid washing, to reduce the amount of discoloration inhibitor used, to suppress the corrosion of the steel material base, and to reduce the quality of the steel surface after pickling. In addition, an inhibitor for steel that improves the quality and yield of the steel without impairing the removal rate of the oxide film and scale adhering to the surface of the steel, an acid cleaning liquid composition in which the inhibitor is added to a hydrochloric acid cleaning liquid, and the acid It is to provide an acid cleaning method using a cleaning liquid composition.

  The present invention relates to an inhibitor added to a hydrochloric acid cleaning solution for steel, wherein (a) 100 parts by weight of a high molecular amine having a molecular weight of 1000 or more, (b) 400 to 1000 weights of a medium molecular amine having a molecular weight of 250 to 1,000. Parts, (c) 100 to 200 parts by weight of a low molecular amine having a molecular weight of less than 250, (d) 200 to 1000 parts by weight of an acetylenic alcohol, (e) 100 to 500 parts by weight of a polyether, and water. An inhibitor characterized by having an excellent yellowing prevention effect in the water washing step after hydrochloric acid washing.

  Further, the present invention provides a diallylamine salt polymer, a diallylamine salt / sulfur dioxide copolymer, a polycondensate of dicyandiamide and diethylenetriamine, a polyethyleneimine, and epichlorohydride having a molecular weight of 1000 or more. It is one or more polymer amines selected from addition polymers of phosphorus and dimethyltriamine.

  In the present invention, the intermediate molecular amine (b) is a polycondensation product of metaxylenediamine and epichlorohydrin having a molecular weight of 250 or more and less than 1000, addition polymerization of polyethyleneimine or epichlorohydrin and dimethyltriamine. It is characterized by being one or more kinds of medium molecular amines selected from those.

  The present invention is characterized in that the low molecular amine of (c) is one or more low molecular amines selected from xylenediamine, polyethylenehexamine, diethanolamine and urea.

  In the present invention, the acetylenic alcohol (d) is selected from the group consisting of 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, 2,5-dimethyl-3-hexyne-2, It is one or more acetylenic alcohols selected from 5-diol and 3,6-dimethyl-4-octyne-3,6-diol.

The present invention is characterized in that the polyether (e) is at least one polyether selected from polyethylene glycol, polypropylene glycol and glycerin.
The present invention is characterized by further containing an organic carboxylic acid.

  The present invention is the acid cleaning liquid composition, wherein the inhibitor is added to a hydrochloric acid cleaning liquid having a pH of 2 or less so that the polymer amine contained in the inhibitor is 1 to 4 mg / L.

  The present invention is a method for cleaning a steel material, wherein the steel material is pickled with the acid cleaning liquid composition and then the steel material is washed with water.

  When the steel material is acid-washed, the inhibitor of the present invention can suppress yellowing in the water washing step after washing, reduce the amount of discoloration inhibitor used, and suppress corrosion of the steel material base. Further, the quality and yield of the steel material can be improved without deteriorating the quality of the surface of the steel material after pickling, without impairing the removal rate of the oxide film and scale adhering to the steel material surface.

Although the reason for the above effect is not clear, it can be estimated as follows.
First, the corrosion of iron in the acid solution can be expressed by electrochemical reaction formulas (1) and (2). When viewed microscopically, the surface of the steel material is formed of an aggregate of local cells composed of an anode portion and a cathode portion, and serves as a driving force for corrosion.

At the anode part, Fe ²⁺ elutes and electrons e ⁻ move through the iron and move to the cathode part. For this reason, the cathode portion has a high electron density and a negative charge, and conversely, the anode portion has a low electron density and a positive charge.
Anode reaction Fe → Fe ²⁺ + 2e ⁻ (1)
Cathode reaction 2H ⁺ + 2e ⁻ → H ₂ (2)

On the other hand, in the gas phase portion, oxidation by atmospheric O ₂ proceeds and discoloration occurs. This can be expressed by electrochemical reaction formulas (3) to (8). The Fe ²⁺ eluted by the anodic reaction is further oxidized in the atmosphere to become Fe ³⁺ , which is combined with the OH ⁻ generated by the cathodic reaction to produce iron oxides such as Fe (OH) ₃ , FeOOH, Fe ₂ O _3, and discoloration. Produce.
Anode reaction 4Fe → 4Fe ²⁺ + 8e ⁻ (3)
Anode reaction (II) 4Fe ²⁺ → 4Fe ³⁺ + 4e ⁻ (4)
Cathode reaction 3O ₂ + 6H ₂ O + 12e ⁻ → 12OH ⁻ (5)
4Fe ³⁺ + 12OH ⁻ → 4Fe (OH) ₃ (6)
4Fe (OH) ₃ → 4FeOOH + 4H ₂ O (7)
4FeOOH → 2Fe ₂ O ₃ + 2H ₂ O (8)

In addition, if corrosion during acid cleaning is large, the surface of the steel material is roughened, and a large amount of chlorine ions (Cl ⁻ ) remain. Chlorine ions, also called erodible ions, penetrate into the base material while destroying the oxide film, and cause local corrosion such as pitting corrosion of steel materials. Chlorine ions remaining at the site are washed and washed. Causes yellowing.
Therefore, in order to suppress yellowing at the time of washing with water and after washing with water, the yellowing reaction is also suppressed by suppressing the corrosion reaction at the time of acid washing, that is, improving the rough surface of the steel surface (such as smoothing the surface). The

  Since the high molecular amine compound contains a large number of nitrogen atoms that are adsorbing groups to iron, electrostatic adsorption to steel is strong and excellent in inhibiting corrosion. However, since the intermolecular gaps are large, local corrosion is likely to occur, and surface roughness occurs. However, when the intermolecular gaps are small, local corrosion is unlikely to occur due to the use of low molecular weight amines. Can do.

  Since the acetylenic alcohol contains oxygen atoms that are adsorbing groups to iron, it is adsorbed electrostatically to the steel material and forms a precipitated film due to its own polymerization reaction, which is excellent in inhibiting corrosion. Furthermore, the gap between molecules is small, and local corrosion is difficult to occur and surface roughness can be suppressed.

Polyether is an auxiliary component and its inhibitory effect itself is weak, but it reduces the interfacial tension at the interface between the steel surface and the acid solution (solid-liquid interface), thus improving the wettability of the steel surface. There is. Therefore, the inhibitor component can be uniformly adsorbed, and the polyether also has a weak shielding effect, thereby suppressing local corrosion.
The inhibitor of the present invention suppresses the yellowing reaction by suppressing the corrosion reaction during acid cleaning, that is, improving the rough surface state of the steel surface (smoothing the surface, etc.) due to the synergistic effect of the above components. .

  The inhibitor of the present invention is an inhibitor to be added to a hydrochloric acid cleaning solution for steel, and (a) 100 parts by weight of a high molecular amine having a molecular weight of 1000 or more, and (b) a medium molecular amine having a molecular weight of 250 or more and less than 1000 to 400 to 1,000. 1000 parts by weight, (c) 100 to 200 parts by weight of a low molecular amine having a molecular weight of less than 250, (d) 200 to 1000 parts by weight of an acetylenic alcohol, (e) 100 to 500 parts by weight of a polyether, water, And an inhibitor having an excellent anti-yellowing effect in the water washing step after hydrochloric acid washing.

  In the present invention, (a) includes a diallylamine salt polymer having a molecular weight of 1000 or more, a diallylamine salt / sulfur dioxide copolymer, a polycondensate of dicyandiamide and diethylenetriamine, addition of polyethyleneimine and epichlorohydrin and dimethyltriamine. One or more polymer amines selected from polymers are listed.

（式中、Ｒ^１およびＲ^２は、同一または異なって水素原子またはメチル基であることを表し、Ｒ^３はメチレン基または式−Ｃ（Ｈ_２）Ｓ（Ｏ_２）−で示される基であることを表す。またＸはハロゲン原子であることを表す）
で示される繰り返し単位を主成分とする高分子アミンである。 The diallylamine salt polymer and diallylamine salt / sulfur dioxide copolymer are represented by the following general formula (1):

Wherein R ¹ and R ² are the same or different and each represents a hydrogen atom or a methyl group, and R ³ is a methylene group or a group represented by the formula —C (H ₂ ) S (O ₂ ) —. (X represents a halogen atom)
It is a polymeric amine which has as a main component the repeating unit shown by these.

  In the present invention, the repeating unit corresponds to a monomer in the polymer, and becomes a constituent of the present invention by bonding one or more repeating units until the repeating unit has a predetermined molecular weight. The term “main component” is used to indicate that the repeating unit is included in 80% or more.

で示される繰り返し単位を主成分とする高分子アミンである。 The polycondensate of dicyandiamide and diethylenetriamine is represented by the following general formula (2)

It is a polymeric amine which has as a main component the repeating unit shown by these.

（式中、Ｒ^４、Ｒ^５およびＲ^６は、同一または異なって炭素数が１〜３のアルキル基であることを表す）
で示される繰り返し単位を主成分とする高分子アミンである。 Polyethyleneimine has the following general formula (3)

(Wherein R ⁴ , R ⁵ and R ⁶ are the same or different and represent an alkyl group having 1 to 3 carbon atoms)
It is a polymeric amine which has as a main component the repeating unit shown by these.

（式中、Ｘはハロゲン原子であることを表す）
で示される繰り返し単位を主成分とする高分子アミンである。 An addition polymerization product of epichlorohydrin and dimethyltriamine has the following general formula (4).

(In the formula, X represents a halogen atom)
It is a polymeric amine which has as a main component the repeating unit shown by these.

In the present invention, any polymer amine having a molecular weight of 1000 or more can be suitably used, but preferably a polymer amine having a molecular weight of 1800-7900, more preferably having a molecular weight of 2500-5000. High molecular amines can be mentioned.
These polymeric amines may be used alone or in combination of two or more.

  All of the above polymer amines are known compounds, and commercially available ones can be used. Examples of such commercially available ones include diallylamine salt polymers (trade names: PAS-24, PAS-H-1L, PAS-H-5L, PAS-H-10L, manufactured by Nitto Bo Medical Co., Ltd., diallylamine salt / sulfur dioxide copolymer (trade names PAS-2401, PAS-A-1, PAS-A-5, Nitto Bo Medical Co., Ltd.) ), Polycondensate of dicyandiamide and diethylenetriamine (trade names Unisense KHP10L, Unisense KHP10P, manufactured by Senka Corporation) (trade name Neofix E-117, manufactured by Nikka Chemical Co., Ltd.), polyethyleneimine (trade name Epomin SP- 012, SP-018, SP-200, P-1000, Nippon Shokubai Co., Ltd. Ltd.), addition polymer of epichlorohydrin and dimethyl triamine (tradename Kachiomasuta PD-10, Kachiomasuta PD-30, manufactured by Yokkaichi Chemical Co., Ltd.) and the like.

  In the present invention, (b) is one kind selected from polycondensation products of metaxylenediamine and epichlorohydrin, addition polymers of polyethyleneimine and epichlorohydrin and dimethyltriamine having a molecular weight of 250 or more and less than 1,000. Examples of the above medium molecular amines.

において、括弧内の式で示される繰り返し単位を主成分とする中分子アミンである。 The condensation polymer of metaxylenediamine and epichlorohydrin has the following general formula (5)

Are medium molecular amines whose main component is a repeating unit represented by the formula in parentheses.

Moreover, as said polyethyleneimine, the medium molecular amine which has the repeating unit shown by said Formula (3) as a main component is mention | raise | lifted.
Furthermore, examples of the addition polymerization product of epichlorohydrin and dimethyltriamine include a medium molecular amine mainly composed of the repeating unit represented by the formula (4).

The medium molecular amine is preferably a medium molecular amine having a molecular weight of 274 to 600, and more preferably a medium molecular amine having a molecular weight of 328 to 600.
These medium molecular amines may be used alone or in combination of two or more.

  All of the above-mentioned medium molecular amines are known compounds, and commercially available ones can be used. Examples of such commercially available ones include a polycondensation product of metaxylenediamine and epichlorohydrin (trade name: Gascamine 328). , Manufactured by Mitsubishi Gas Chemical Company, Inc.), polyethyleneimine (trade name: Epomin SP-003, Epomin SP-006, manufactured by Nippon Shokubai Co., Ltd.), addition polymer of epichlorohydrin and dimethyltriamine (trade name: Cathiomaster PD-2) , Cachio Master PD-3, manufactured by Yokkaichi Gosei Co., Ltd.) and the like.

Furthermore, examples of (c) include one or more low-molecular amines selected from xylenediamine, polyethylenehexamine, diethanolamine, and urea.
Among these low molecular amines, xylenediamine or polyethylenehexamine is preferable among those exemplified above.

The low molecular amine is preferably a low molecular amine having a molecular weight of 60 to 232, and more preferably a low molecular amine having a molecular weight of 136 to 232.
These low molecular amines may be used alone or in combination of two or more.

  These low molecular amines are all known compounds, and commercially available ones can be used.

（但し、式中、Ｒ^７は、メチル基またはエチル基であることを表す） Furthermore, as said (d), Formula (6)

(In the formula, R ⁷ represents a methyl group or an ethyl group)

（但し、式中、Ｒ^８およびＲ^９は、同一または異なって、メチル基またはエチル基であることを表す）
で示されるアセチレン系アルコールがあげられる。 Or formula (7)

(In the formula, R ⁸ and R ⁹ are the same or different and represent a methyl group or an ethyl group)
An acetylenic alcohol represented by

Specific examples of the acetylenic alcohol include 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, and 2,5-dimethyl-3-hexyne-2,5-diyl. 3,6-dimethyl-4-octyne-3,6-diyl and the like.
Among these, 3-methyl-1-butyn-3-ol or 3-methyl-1-pentyn-3-ol is preferable.
These acetylenic alcohols may be used alone or in combination of two or more.

  These acetylenic alcohols are all known compounds, and commercially available products can be used.

Furthermore, examples of (e) include one or more of polyethylene glycol, polypropylene glycol, and polyglycerin.
Among these, polyethylene glycol or polypropylene glycol is preferable.
These polyethers may be used alone or in combination of two or more.

  These polyethers are all known compounds, and commercially available products can be used.

The inhibitor of the present invention may contain an organic carboxylic acid in addition to the above-mentioned components, and the organic carboxylic acid is preferable because the above polymer, medium molecule and low molecular amine are stably dissolved in the inhibitor.
Examples of such carboxylic acids include organic carboxylic acids having 5 or less carbon atoms. Examples of organic carboxylic acids include aliphatic monocarboxylic acids, dicarboxylic acids, saturated carboxylic acids, unsaturated carboxylic acids, oxocarboxylic acids, and hydroxycarboxylic acids. And ketocarboxylic acid.

Such carboxylic acids are specifically formic acid, acetic acid, propargic acid, propionic acid, glyoxylic acid, glycolic acid, crotonic acid, isobutyric acid, pyruvic acid, oxalic acid, lactic acid, malonic acid, hydroxybutyric acid, glyceric acid, maleic acid Succinic acid, tartronic acid, citraconic acid, itaconic acid, glutaric acid, malic acid, diglycolic acid, citramalic acid, tartaric acid and the like.
One or more of these carboxylic acids may be used in combination, and the carboxylic acid is not limited to a free one, and may be a carboxylate.

The inhibitor of the present invention can be produced by mixing each component described above with water at room temperature to warming.
The mixing of these components is not particularly limited. For example, each component can be mixed in water to a predetermined amount while stirring at room temperature and stirred.
In addition, the polymer, medium molecule, and low molecular amine can be stably dissolved using an organic carboxylic acid having 5 or less carbon atoms.

  The concentration of the mixture at this time may be such that the total amount of each component is about 5 to 30 parts by weight with respect to 100 parts by weight of water. Can be used diluted.

  The inhibitor of the present invention thus obtained suppresses corrosion of the steel material base and suppresses yellowing in the water washing step after hydrochloric acid washing, thereby improving the quality and yield of the steel material. In addition, the amount of the anti-discoloring agent used can be reduced, and the inhibitor can reduce the environmental impact.

  The acid cleaning liquid composition of the present invention is a hydrochloric acid cleaning liquid having a pH of 2 or less added so that the polymer amine contained in the inhibitor is 1 to 4 mg / L.

  The hydrochloric acid cleaning liquid in the acid cleaning liquid composition may be any hydrochloric acid that is suitable for cleaning steel materials in water, and has a pH of 2 or less.

  The inhibitor can be added to the hydrochloric acid washing solution by adding the inhibitor to the hydrochloric acid washing solution at room temperature and mixing. At this time, the concentration of the polymer amine in the inhibitor is within the above concentration range. What is necessary is just to adjust the quantity of a washing | cleaning liquid or an inhibitor.

  The steel material cleaning method of the present invention can be carried out by pickling a steel material with the acid cleaning liquid composition and then washing the steel material with water.

  It is preferable to use a continuous hydrochloric acid cleaning equipment for cleaning the steel. The pickling temperature of the steel is generally 20 to 95 ° C., and the inhibitor of the present invention can be used stably in this temperature range.

  The inhibitor of the present invention may be added to a hydrochloric acid aqueous solution at the time of use, or may be added to a hydrochloric acid aqueous solution in advance to obtain a pickling solution composition, which can be used as it is during pickling or after being diluted with water. .

  In addition, the inhibitor of the present invention and the acid cleaning liquid composition containing the inhibitor are used for acid cleaning of steel, and examples of the target metal include steel, carbon steel, alloy steel, and special steel.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples and comparative examples. However, the following examples do not limit the present invention.
The evaluation was performed as follows.

<Evaluation of yellowing suppression effect>
A hydrochloric acid aqueous solution containing 100 g of hydrochloric acid and 100 g of ferrous ion in 1 L (liter) of an aqueous solution was prepared. After this acid cleaning solution is heated to 80 ° C., a 270 MPa class hot rolled steel with a mill scale is immersed for 2 minutes, immediately washed with running water spray (0.24 L / min) for 10 seconds, and then 50 ml of water. About 1/3 of the hot-rolled steel is immersed in a solution containing 0.1 ml of the pickling solution in it, lightly covered with a wrap and allowed to stand for 5 minutes, and the yellowing degree (b value) of the steel surface is determined. Measurement was performed with a spectrocolorimeter (CM-508c, manufactured by Minolta Co., Ltd.). Based on the degree of yellowing when using a commercially available corrosion inhibitor, the yellowing suppression effect was evaluated as follows.
◎: Reduction rate of 45% or more with respect to the standard yellowing degree ○: Reduction rate of 35% or more and less than 45% with respect to the standard yellowing degree △: Reduction rate of 25% or more and less than 35% with respect to the standard yellowing degree Reduction rate of less than 25%

<Evaluation of corrosion inhibition effect>
A hydrochloric acid aqueous solution containing 120 g of hydrochloric acid and 100 g of ferrous ion in 1 L (liter) of the aqueous solution was prepared. After this acid cleaning liquid was heated to 85 ° C., a 270 MPa class hot rolled steel material from which mil scale and rust had been removed was immersed for 5 minutes, and the amount of corrosion was measured. Based on the removal time when a commercially available corrosion inhibitor was used, the corrosion inhibition effect was evaluated as follows.
◎: Increase rate of less than 1% with respect to the reference corrosion rate ○: Increase rate of 1% to less than 5 with respect to the reference corrosion amount △: Increase rate with respect to the reference corrosion amount of 5% to less than 10% ×: Increase rate with respect to the reference corrosion amount 10% or more

<Evaluation of pickling effect>
A hydrochloric acid aqueous solution containing 120 g of hydrochloric acid and 100 g of ferrous ion in 1 L (liter) of the aqueous solution was prepared. After this acid cleaning solution was heated to 85 ° C., a 270 MPa class hot-rolled steel material with a mill scale was immersed, and the surface mill scale and rust removal time were measured. The pickling effect was evaluated as follows based on the removal time when a commercially available corrosion inhibitor was used.
◎: Delay rate of less than 5% with respect to reference time ○: Delay rate of 5% to less than 10% with respect to reference time △: Delay rate of 10% to less than 15% with respect to reference time ×: Delay rate of 15% or more with respect to reference time

  The effects of the inhibitor of the present invention in the acid cleaning solution were evaluated by Examples 1 to 14 and Comparative Examples 1 to 11 shown below. The evaluation results are shown in the table.

Example 1
As a high molecular amine, a diallylamine salt / sulfur dioxide copolymer having a molecular weight of 5000 (trade name: PAS-A-1, manufactured by Nitto Bo Medical Co., Ltd., hereinafter referred to as (a) -1), and a metaxylene having a molecular weight of 328 as a medium molecular amine. Condensation product of diamine and epichlorohydrin (trade name: Gascamine 328, manufactured by Mitsubishi Gas Chemical Co., Ltd., hereinafter referred to as (b) -1), metaxylenediamine having a molecular weight of 136 as a low molecular amine (Wako Pure Chemical Industries, Ltd.) Manufactured, hereinafter referred to as (c) -1), 3-methyl-1-butyn-3-ol (manufactured by Tokyo Chemical Industry Co., Ltd., hereinafter referred to as (d) -1) as acetylenic alcohol, and polyethylene as polyether Each component of glycol (manufactured by Wako Pure Chemical Industries, Ltd., hereinafter referred to as (e) -1) is in parts by weight as shown in Table 1. Combined and were prepared inhibitors of the present invention.

  300 ppm of the obtained inhibitor was added to the hydrochloric acid aqueous solution used in each of the above-mentioned evaluation items to prepare an inhibitor-containing acid cleaning liquid (acid cleaning liquid composition) containing 2 mg / L of a polymeric amine in the hydrochloric acid aqueous solution. The effect was evaluated.

Example 2
Instead of the polymer amine (a) -1, a polycondensate of dicyandiamide having a molecular weight of 2500 and diethylenetriamine (trade name Neofix E-117, manufactured by Nikka Chemical Co., Ltd., hereinafter referred to as (a) -2) is used. The others were carried out in the same manner as in Example 1.

Example 3
The same as Example 1 except that polyethyleneimine having a molecular weight of 1800 (trade name Epomin SP-018, manufactured by Nippon Shokubai Co., Ltd., hereinafter referred to as (a) -3) is used in place of the polymeric amine (a) -1. Implemented.

Example 4
In place of the high molecular amine (a) -1, an addition polymer of epichlorohydrin having a molecular weight of 7900 and dimethyltriamine (trade name Kathiomaster PD-30, manufactured by Yokkaichi Chemical Co., Ltd., hereinafter referred to as (a) -4) This was carried out in the same manner as in Example 1 except that

Example 5
The same as Example 1 except that polyethyleneimine having a molecular weight of 600 (trade name Epomin SP-006, manufactured by Nippon Shokubai Co., Ltd., hereinafter referred to as (b) -2) is used instead of the medium molecular amine (b) -1. Implemented.

Example 6
Instead of the medium molecular amine (b) -1, an addition polymer of epichlorohydrin having a molecular weight of 274 and dimethyltriamine (trade name: Cathiomaster PD-2, manufactured by Yokkaichi Gosei Co., Ltd., hereinafter referred to as (b) -3) This was carried out in the same manner as in Example 1 except that

Example 7
The same procedure as in Example 1 was conducted except that pentaethylenediamine having a molecular weight of 232 (manufactured by Wako Pure Chemical Industries, Ltd., hereinafter referred to as (c) -2) was used instead of the low molecular amine (c) -1.

Example 8
The same procedure as in Example 1 was performed except that diethanolamine having a molecular weight of 105 (manufactured by Wako Pure Chemical Industries, Ltd., hereinafter referred to as (c) -3) was used instead of the low molecular amine (c) -1.

Example 9
The same procedure as in Example 1 was performed except that urea having a molecular weight of 60 (manufactured by Wako Pure Chemical Industries, Ltd., hereinafter referred to as (c) -4) was used instead of the low molecular amine (c) -1.

Example 10
The same as Example 1 except that 3-methyl-1-pentyn-3-ol (manufactured by Tokyo Chemical Industry Co., Ltd., hereinafter referred to as (d) -2) is used in place of the acetylenic alcohol (d) -1. Implemented.

Example 11
Implementation was performed except that 2,5-dimethyl-3-hexyne-2,5-ziel (manufactured by Tokyo Chemical Industry Co., Ltd., hereinafter referred to as (d) -3) was used in place of the acetylenic alcohol (d) -1. Performed as in Example 1.

Example 12
Implementation was performed except that 3,6-dimethyl-4-octyne-3,6-diel (manufactured by Tokyo Chemical Industry Co., Ltd., hereinafter referred to as (d) -4) was used in place of the acetylenic alcohol (d) -1. Performed as in Example 1.

Example 13
The same procedure as in Example 1 was performed except that polypropylene glycol (manufactured by Wako Pure Chemical Industries, Ltd., hereinafter referred to as (e) -2) was used instead of (e) -1.

Example 14
The same procedure as in Example 1 was performed except that polyglycerin (manufactured by Sakamoto Pharmaceutical Co., Ltd., hereinafter referred to as (e) -3) was used as the polyether instead of (e) -1.

Comparative Example 1
Instead of the inhibitor of the present invention, diallylamine salt / sulfur dioxide copolymer, condensation product of metaxylenediamine and epichlorohydrin, metaxylenediamine, 3-methyl-1-butyn-3-ol, and polyethylene glycol are mainly used. Implemented in the same manner as in Example 1 except that 500 ppm of a commercially available corrosion inhibitor (trade name: New Hyper DS-1N (manufactured by Asahi Chemical Industry Co., Ltd.)) contained as a component was added to the aqueous hydrochloric acid solution used in each of the above evaluation items. did.

Comparative Example 2
It carried out like Example 1 except not containing a high molecular amine.

Comparative Example 3
The same operation as in Example 1 was carried out except that the content of the polymer amine was as shown in Table 1.

Comparative Example 4
It carried out like Example 1 except not containing a middle molecular amine.

Comparative Example 5
The same operation as in Example 1 was carried out except that the content of medium molecular amine was as shown in Table 1.

Comparative Example 6
It carried out like Example 1 except not containing a low molecular amine.

Comparative Example 7
The same operation as in Example 1 was carried out except that the content of the low molecular amine was as shown in Table 1.

Comparative Example 8
It implemented like Example 1 except not containing an acetylenic alcohol.

Comparative Example 9
The same procedure as in Example 1 was performed except that the content of acetylenic alcohol was as described in Table 1.

Comparative Example 10
It carried out like Example 1 except not containing a polyether.

Comparative Example 11
The same procedure as in Example 1 was carried out except that the polyether content was as shown in Table 1.

  The results are as shown in Table 1.

  As is apparent from the evaluation results with Examples 1 to 14 and Comparative Examples 1 to 11 shown below, the inhibitor of the present invention is excellent in yellowing suppression effect in the water washing step after hydrochloric acid washing and inhibits scale removability. It is excellent in corrosion inhibition effect.

As described above, yellowing can be suppressed in the water washing process after hydrochloric acid washing, the amount of discoloration inhibitor used can be reduced, corrosion of the steel substrate can be suppressed, and the quality of the steel surface after pickling can be reduced. It does not hinder the removal rate of oxide film and scale adhering to the steel material surface, and improves the quality and yield of the steel material.
In addition, it is an inhibitor that can reduce the amount of anti-discoloring agent used and reduce the impact on the environment, and its industrial effect is very large.

Claims (9)

An inhibitor added to a hydrochloric acid cleaning solution for steel,
(A) 100 to 100 parts by weight of a high molecular amine having a molecular weight of 1000 or more, (b) 400 to 1000 parts by weight of a medium molecular amine having a molecular weight of 250 to 1,000, and (c) 100 to 100% of a low molecular amine having a molecular weight of less than 250. An inhibitor comprising 200 parts by weight, (d) 200 to 1000 parts by weight of an acetylenic alcohol, (e) 100 to 500 parts by weight of a polyether, and water.   Addition of diallylamine salt polymer, diallylamine salt / sulfur dioxide copolymer, polycondensate of dicyandiamide and diethylenetriamine, polyethyleneimine, epichlorohydrin and dimethyltriamine having a molecular weight of 1000 or more. The inhibitor according to claim 1, wherein the inhibitor is at least one polymer amine selected from polymers.   The medium molecular amine (b) is one selected from a polycondensation product of metaxylenediamine and epichlorohydrin, a polyethyleneimine and an addition polymer of epichlorohydrin and dimethyltriamine, having a molecular weight of 250 or more and less than 1,000. The inhibitor according to claim 1, wherein the inhibitor is a medium molecular amine.   The inhibitor according to claim 1, wherein the low molecular amine of (c) is at least one low molecular amine selected from xylenediamine, polyethylenehexamine, diethanolamine, and urea.   The acetylenic alcohol of (d) is 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, 2,5-dimethyl-3-hexyne-2,5-diol and The inhibitor according to claim 1, wherein the inhibitor is one or more acetylenic alcohols selected from 3,6-dimethyl-4-octyne-3,6-diol.   The inhibitor according to claim 1, wherein the polyether (e) is one or more polyethers selected from polyethylene glycol, polypropylene glycol and glycerin.   The inhibitor according to any one of claims 1 to 6, further comprising an organic carboxylic acid.   The acid according to any one of claims 1 to 7, wherein the inhibitor according to any one of claims 1 to 7 is added to a hydrochloric acid washing solution having a pH of 2 or less so that the polymer amine contained in the inhibitor is 1 to 4 mg / L. Cleaning liquid composition.   9. A method for cleaning a steel material comprising: pickling a steel material with the acid cleaning liquid composition according to claim 8 and then rinsing the steel material with water.