KR100323618B1 - An acidic compound for cleaning metal material and a compound for adding in the same - Google Patents

Abstract

The present invention relates to an acid-cleaning composition capable of effectively inhibiting corrosion of a metal to be cleaned, and an additive added to the composition, without lowering the cleaning rate during pickling of a metal material using an organic or inorganic acid.

The pickling additive according to the present invention may be any one of (a) a condensate of dicyandiamide and formaldehyde satisfying formula 1 below and a polycondensate of alkylenediamine and epichlorohydrin satisfying formula 2 below: 30% by weight of these mixed components; (b) 5 to 20% by weight of alkylene diamines.

Formula 1

(HOCH ₂ ) nNRC (NH) NHCN

(Where R = H when n = 1, and R = none when n = 2)

Formula 2

Where R = alkylene group and n = integer

Description

Pickling composition of metal materials and pickling additive added to the composition {AN ACIDIC COMPOUND FOR CLEANING METAL MATERIAL AND A COMPOUND FOR ADDING IN THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for cleaning a metal material, and particularly, to an acid cleaning composition and an acid cleaning composition which can effectively suppress corrosion of a metal to be cleaned without lowering the cleaning speed during pickling of a metal material using organic or inorganic acids. It relates to an additive to be added.

In order to remove scale due to oxide film or hardness component such as rust attached to metal surface, pickling method using inorganic acid or organic acid is widely used.

However, while the pickling method has an advantage of easily removing rust or scale, there is a problem of corroding the metal to be cleaned or causing weakness, formula, etc. due to hydrogen ions. In particular, in the case of high tensile steel containing a large amount of manganese (Mn), problems due to pickling appear more seriously.

Therefore, conventionally, in order to suppress corrosion during pickling, a compound having excellent adsorption to the metal surface and a protective coating property, that is, an organic compound having a lone pair of electrons such as nitrogen, oxygen, and sulfur, has been used.

However, when such an organic compound is added to the pickling solution as a corrosion inhibitor, the cleaning speed is lowered and the working efficiency is relatively lowered. In order to increase the cleaning speed without degrading the performance of the corrosion inhibitor, it is necessary to remove the solid oxide film quickly by increasing the acid concentration or raising the temperature of the pickling solution. That is, the development of a new corrosion inhibitor that is stable at higher temperatures and even at higher acid concentrations is required.

On the other hand, Japanese Patent Application Laid-Open No. 47-34122 proposes a method of adding a reducing agent, which is an acid pickling accelerator, in addition to the corrosion inhibitor. In addition, Japanese Patent Application Laid-Open No. 49-106440 uses polyethyleneamine which is a kind of polymer organic amine, Japanese Patent Application Laid-Open No. 57-198273 adds a surfactant, Japanese Patent Application Laid-Open No. 63-203780 adds an oxidizing agent, and Japanese Patent Laid-Open No. 3-3317 adds an organic sulfur compound, and Japanese Patent Laid-Open No. 10-140379 uses a sulfur compound for polyethyleneamines.

However, the above-mentioned prior arts do not have sufficient pickling promotion and corrosion inhibiting effects, and the metal surface after pickling turns black, causing quality deterioration. In addition, breakage may occur frequently during high tensile steel pickling in cold rolling, and may adversely affect the environment by generating SOx gas in the pickling solution recovery process.

The present invention is directed to solving this problem of the prior art and meeting the technical demands at hand.

That is, an object of the present invention is to provide an acid-cleaning composition and an additive added to the composition, which can effectively suppress corrosion of the metal material during pickling and also increase the cleaning speed.

Further, another object of the present invention is to provide an acid-cleaning composition which is stable even at high temperature pickling and which is added to the composition.

Other objects and advantages of the invention will be described below and will be appreciated by the practice of the invention. Furthermore, the objects and advantages of the present invention can be realized by means and combinations indicated in the appended claims.

In order to achieve the above object, one aspect of the acid-cleaning additive according to the present invention is (a) a condensate of dicyandiamide and formaldehyde satisfying the formula (1) below and alkylenediamine satisfying the formula (2) and 30% by weight of any one of polycondensates of epichlorohydrin or a mixture thereof; (b) 5 to 20% by weight of alkylene diamines.

(Formula 1)

(HOCH ₂ ) nNRC (NH) NHCN

(Where R = H when n = 1, and R = none when n = 2)

(Formula 2)

Where R = alkylene group and n = integer

Therefore, the pickling additive of the present invention can suppress corrosion generated during pickling of the metal material and can effectively increase the pickling rate.

In addition, the pickling additive may further include 0.5 to 7% by weight of a cationic surfactant satisfying the formula (3) below.

(Formula 3)

(Wherein R ₁ = long-chain alkyl group, R ₂ to R ₄ = C ₁ to C ₂ alkyl group, X = Br or Cl)

In addition, the acid cleaning additive to which the cationic surfactant is added may further include 0.5 to 1% by weight of a nonionic surfactant satisfying the following Formula 4.

(Formula 4)

R-O- (A0) n-H

(Wherein R = C ₁₂ to C ₁₈ alkyl or alkenyl group, AO = C ₂ to C ₄ oxyalkylene group, n = 5 or more integer)

Another aspect of the pickling additive according to the present invention is (a) a condensate of dicyandiamide and formaldehyde satisfying formula 1 below and a polycondensate of alkylenediamine and epichlorohydrin satisfying formula 2 below 30 wt% of any one or mixed components thereof;

(Formula 1)

(HOCH ₂ ) nNRC (NH) NHCN

(Where R = H when n = 1, and R = none when n = 2)

(Formula 2)

Where R = alkylene group and n = integer

(b) 20% by weight of alkylene diamines;

(c) 0.5 to 1% by weight of a cationic surfactant satisfying the following Formula 3; And

(Formula 3)

(Wherein R ₁ = long-chain alkyl group, R ₂ to R ₄ = C ₁ to C ₂ alkyl group, X = Br or Cl)

(d) 0.5 to 1% by weight of a nonionic surfactant satisfying the following formula (4).

(Formula 4)

R-O- (A0) n-H

(Wherein R = C ₁₂ to C ₁₈ alkyl or alkenyl group, AO = C ₂ to C ₄ oxyalkylene group, n = 5 or more integer)

As a specific example of the said nonionic surfactant, the compound which added ethylene oxide, propylene oxide, etc. to _C12 - _C18 alcohols, such as lauryl alcohol, oleyl alcohol, nonylphenol, and stearyl alcohol, is mentioned.

The alkylene diamines are any one selected from the group consisting of ethylene diamine, detramethylenediamine, hexamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, and especially decamethylenediamine is mainly used.

In addition, the cationic surfactant is any one selected from the group comprising dodecyltrimethylammonium chloride, detradecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, dodecylbenzyldimethylammonium chloride and octadecyltrimethylammonium chloride, in particular Preference is given to dodecylbenzyldimethylammonium chloride.

In addition, the pickling composition of the present invention is made by adding 0.0001 to 5% by weight of the pickling additive to the acid solution used as the cleaning liquid. In particular, it is preferable to add 0.001-0.5% by weight of the acid-cleaning additive (general steel: 0.05% by weight, high tensile steel: 0.1% by weight) to the acid solution.

At this time, the acid solution to be used is an acid component selected from inorganic acids such as sulfuric acid, hydrochloric acid, phosphoric acid, sulfamic acid, hydrofluoric acid, nitric acid, and organic acids such as formic acid, glacial acetic acid, citric acid, tartaric acid, malic acid, gluconic acid, or two selected from them. The above mixed acid component.

The type or concentration of acid component depends on the type and degree of corrosion of the metal material, required pickling speed, pickling temperature, and the like.

Hereinafter, preferred embodiments of the present invention will be described in detail.

Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the configuration of the embodiments described herein is only one of the most preferred embodiments of the present invention and does not represent all of the technical idea of the present invention, various equivalents and modifications that can replace them at the time of the present application It should be understood that there may be

<Production of Condensates of Dicyamide and Formaldehyde>

The condensate of Chemical Formula 1 may be prepared by reacting 2 to 3 mol of formaldehyde with respect to the following Scheme 1, that is, 1 mol of dicyanamide.

H ₂ NC (NH) NHCN + nHCHO → (HOCH ₂ ) nNRC (NH) NHCN

At this time, when the dicyanamide and formaldehyde is reacted for a long time or at a high temperature, the initial PH starts with acidic or alkaline so that the final PH is 8.5-8.8. In particular, if the formaldehyde is 2 mol or less with respect to 1 mol of dicyanamide, the reactivity is weak, and if it is 3 mol or more, there is a risk of gelation under the influence of time or temperature, which may cause stability problems. Therefore, it is suitable to react formaldehyde about 2.5-2.8 mol with respect to 1 mol of dicyanamide. At this time, the initial pH is more acidic than the alkali side.

<Preparation of polycondensates of alkylenediamine and epichlorohydrin>

The polycondensate of Formula 2 may be prepared by reacting 0.6 to 3 moles of epichlorohydrin with respect to Reaction Scheme 2 below, that is, 1 mole of alkylenediamine.

At this time, when the epichlorohydrin is participated in the reaction of 0.6 mol or less or 3 mol or more, epichlorohydrin is insufficient or excessive with respect to the amine group, which makes it difficult to increase the degree of polymerization during the polycondensation. Since the reaction of alkylenediamine and epichlorohydrin is exothermic, it is preferable to use a solvent, and water is generally used as a solvent.

When making polycondensates of alkylenediamine and epichlorohydrin, PH is important. When reacting in alkaline, it becomes easy to be insoluble or insoluble in water, and when acid is strong, the reaction is suppressed and polycondensation does not occur smoothly. That is, in the polycondensation reaction, the pH of the liquid is suitably about 5 to 10.

As the reaction proceeds, the pH gradually decreases. The initial pH of the reaction has good alkalinity, and when the pH is excessively reduced, the pH should be adjusted by supplementing alkali in the middle.

Reaction temperature and reaction time are important factors that are related to each other, but the reaction rate decreases at low temperature (below about 20 ℃), and raw material loss occurs due to the formation of colored material at high temperature. Therefore, it is preferable to adjust reaction temperature to 20 to 100 degreeC.

In addition, as the reaction time elapses, the solution thickens, but if the polycondensation is excessive, water-insoluble jelly or solids may be formed. Therefore, it is preferable to add an organic acid or an inorganic acid to stabilize the pH to 7 or less.

As the alkylenediamine, for example, ethylenediamine, tetramethylenediamine, hexamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine and the like are used.

Example 1

150 ml of 18% hydrochloric acid as an acid component is added to a 250 ml beaker, where (a) 30 wt% of the condensate of Formula 1, (b) 20 wt% of hexamethylenediamine, and (c) 0.5 wt% of 40 mol nonylphenol and (d ) 75% by weight of dodecylbenzyldimethylammonium chloride and the remainder of the pickling additive (0.05% by weight of the acid solution) consisting of water were added, and the liquid temperature was adjusted to 85 ° C ± 3 ° C to prepare a pickling composition.

Example 2

150 ml of 18% hydrochloric acid as an acid component is added to a 250 ml beaker, where (a) 30 weight percent of polycondensates of Formula 2, (b) 20 weight percent of decamethylenediamine, and (c) 1 weight percent of 40 mol nonylphenol and (d A 75% pickling additive (0.05% by weight of an acid solution) consisting of 1% by weight of dodecylbenzyldimethylammonium chloride and the remaining amount of water was added, and the liquid temperature was adjusted to 85 ° C ± 3 ° C to prepare a pickling composition.

Example 3

150 ml of 18% hydrochloric acid as an acid component is added to a 250 ml beaker, where (a) 10% by weight of the condensate of Formula 1 and (b) 20% by weight of polycondensate of Formula 2 and (c) 20% by weight of hexamethylenediamine And (d) 75 mg (0.05% by weight of an acid solution) of an acid pickling additive comprising 3% by weight of dodecylbenzyldimethylammonium chloride and the remaining amount of water and adjusting the liquid temperature to 85 ° C ± 3 ° C to prepare a pickling composition. It was.

Example 4

150 ml of 18% hydrochloric acid as an acid component is added to a 250 ml beaker, where (a) 30% by weight of the polycondensate of Formula 2, (b) 20% by weight of hexamethylenediamine and the remaining amount of water are 75 mg of a pickling additive (acid solution) 0.05 wt%) was added and the liquid temperature was adjusted to 85 ° C ± 3 ° C to prepare a pickling composition.

Example 5

To a pickling solution containing 100 g of sulfuric acid and 50 g of ferrous ions in 1 L of water, (a) 30% by weight of the polycondensate of Formula 2, (b) 10% by weight of hexamethylenediamine, and (c) dodecylbenzyldimethylammonium chloride 7 A pickling composition was prepared by adding 1 g of a pickling additive (0.05 wt% of an acid solution) consisting of the weight% and the remaining amount of water, and adjusting the liquid temperature to 85 ° C ± 3 ° C.

Example 6

To a pickling solution containing 100 g of sulfuric acid and 50 g of ferrous ion in 1 L of water, (a) 30% by weight of the polycondensate of Formula 2, (b) 5% by weight of decamethylenediamine, and (c) dodecylbenzyldimethylammonium chloride 7 A pickling composition was prepared by adding 1 g of a pickling additive (0.05 wt% of an acid solution) consisting of the weight% and the remaining amount of water, and adjusting the liquid temperature to 85 ° C ± 3 ° C.

Comparative Example 1

In a 250 ml beaker, 150 ml of 18% hydrochloric acid is added as an acid component, where (a) 30% by weight of polyethylene imine and (b) 10% by weight of 2-aminoethanethiol hydrochloride and the remainder are water. 75 mg of the pickling additive (0.05 wt% of the acid solution) formed was added, and the liquid temperature was adjusted to 85 ° C ± 3 ° C to prepare a pickling composition.

Comparative Example 2

150 ml of 18% hydrochloric acid is added to a 250 ml beaker as an acid component, and (a) 75 mg (0.05 wt.% Of an acid solution) of a pickling additive comprising 50% by weight of the condensate of Chemical Formula 1 and the remaining amount of water is added thereto, and the liquid temperature Was adjusted to 85 ° C ± 3 ° C to prepare a pickling composition.

Comparative Example 3

150 ml of 18% hydrochloric acid was added to a 250 ml beaker as an acid component, and (a) 75 mg of a pickling additive (0.05 wt% of an acid solution) consisting of 50 wt% of the polycondensate of Formula 2 and the remaining amount of water was added thereto, and the liquid temperature Was adjusted to 85 ° C ± 3 ° C to prepare a pickling composition.

Comparative Example 4

In a 250 ml beaker, 150 ml of 18% hydrochloric acid is added as an acid component, where (a) 30% by weight of hexamethylenediamine, (b) 15% by weight of dodecylbenzyldimethylammonium chloride and the remaining amount of water are 75 mg of a pickling additive (acid solution) 0.05 wt%) was added and the liquid temperature was adjusted to 85 ° C ± 3 ° C to prepare a pickling composition.

Comparative Example 5

To a pickling solution containing 100 g of sulfuric acid and 50 g of ferrous ion in 1 L of water, 1 g of humulic acid (0.05 wt% of the acid solution) was added as an pickling additive, and the liquid temperature was adjusted to 85 ° C ± 3 ° C to prepare a pickling composition. Prepared.

Comparative Example 6

1 g of piperidine (0.05% by weight of the acid solution) was added to the pickling solution containing 100 g of sulfuric acid and 50 g of ferrous ion in 1 L of water, and the liquid temperature was adjusted to 85 ° C ± 3 ° C. A pickling composition was prepared.

<Test Example 1>

(1) general steel

The weight of the specimen made of cold rolled steel sheet (JIS G3141 1mm × 30mm × 50mm) is measured. Then, the specimen was deposited on the pickling compositions of Examples 1 and 2 and the pickling compositions of Comparative Examples 1 and 2. At this time, the holding liquid temperature was maintained at 85 ° C ± 3 ° C, and the deposition time was 10 minutes.

(2) special steel

Weigh the specimens made of high tensile carbon steel (50mm × 30mm × 2mm) containing 0.9% to 1.2% manganese. In addition, the specimen was deposited on the pickling compositions of Examples 3 and 4 and the pickling compositions of Comparative Examples 3 and 4. At this time, the holding liquid temperature was maintained at 85 ° C ± 3 ° C, and the deposition time was 10 minutes.

Thus, the deposited specimens are washed with water and acetone, dried and observed for appearance and weighed. The corrosion inhibition rate (%) of the corrosion test was calculated based on the following Equation 1 according to the weight reduction of the specimen before and after deposition, and the results are shown in Table 1 below.

Corrosion Inhibition Rate (%) = × 100 ... (1)

Here, A = the specimen was deposited in an pickling composition using only 18% hydrochloric acid without the addition of pickling additives, the amount of corrosion obtained from the weight before and after the deposition, B = to the pickling composition to which the additives of the examples and comparative examples were added The amount of corrosion obtained from the weight of the specimen deposited and before and after deposition

Exterior Corrosion inhibition rate (%) Example 1 Slightly glossy 95 Example 2 Slightly glossy 97 Example 3 Slightly glossy 93 Example 4 Slightly glossy 92 Comparative Example 1 Discolored slightly 88 Comparative Example 2 Discolored slightly 78 Comparative Example 3 Slightly black 66 Comparative Example 4 Slightly black 71

As can be seen from Table 1, the pickling composition of Examples 1 to 4 shows excellent corrosion inhibitory ability in ordinary steel or special steel (near 1% of high tensile steel Mn content), and the degree of surface gloss disappears slightly Indicates.

In contrast, the pickling compositions of Comparative Examples 1 to 4 were discolored in black in special steel, and the corrosion inhibition rate did not reach the reference value.

<Test Example 2>

A specimen made of a hot rolled steel sheet (50 mm × 30 mm × 2 mm) with a mill scale was attached to the pickling composition (heated at 80 ° C.) of Examples 5, 6, 6, and 6. The time required for the deposition of the mill scale deposited on the surface of the specimen was measured. Table 2 below shows the test results measuring the time required to remove the oxide film attached to the metal surface.

Time required to remove oxide film (seconds) Example Example 5 15.7 seconds Example 6 30.1 seconds Comparative example Comparative Example 5 16.3 seconds Comparative Example 6 32.8 seconds No addition No addition 1 21.0 seconds No addition 2 43.2 seconds

(Here, no addition 1 represents an acid cleaning composition containing 100 g of hydrochloric acid and 50 g of ferrous ion in 1 l of water without addition of an acid washing additive, and no addition 2 indicates that 100 g of sulfuric acid and ferrous sulfate were added in 1 l of water without addition of an acid washing additive. Pickling composition containing 50 g of water)

As can be seen from Table 2, Examples 5 and 6 require a shorter time to remove the oxide film of the hot rolled steel sheet as compared with no addition or comparative examples.

The present invention is not limited to the above-described embodiments, and various modifications and variations are made by those skilled in the art within the equivalent scope of the technical concept of the present invention and the claims to be described below. Of course it is possible.

The pickling composition of the present invention has a high oxide film removal rate at high temperature pickling and excellent corrosion inhibition efficiency. In particular, in the case of conventional pickling compositions, the pickling rate is slowed down when the corrosion inhibitory efficiency is increased. However, in the present invention, the corrosion inhibitory efficiency and pickling rate are overcome by overcoming such opposing properties (the pickling rate decreases as the corrosion inhibiting efficiency increases). Can be increased at the same time.

Claims (8)

(a) 30% by weight of a condensate of dicyandiamide and formaldehyde satisfying formula 1 below and any polycondensate of alkylenediamine and epichlorohydrin satisfying formula 2 below, ; Formula 1 (HOCH ₂ ) nNRC (NH) NHCN (Where R = H when n = 1, and R = none when n = 2) Formula 2 Where R = alkylene group and n = integer (b) Pickling additives for inhibiting corrosion generated during pickling of metal materials, and increasing pickling rates, comprising 5 to 20% by weight of alkylene diamines. The method of claim 1, Pickling additive, characterized in that it further comprises 0.5 to 7% by weight of a cationic surfactant satisfying the formula (3) below. Formula 3 (Wherein R ₁ = long-chain alkyl group, R ₂ to R ₄ = C ₁ to C ₂ alkyl group, X = Br or Cl) The method of claim 2, Pickling additive, characterized in that it further comprises 0.5 to 1% by weight of a nonionic surfactant satisfying the formula (4). Formula 4 R-O- (A0) n-H (Wherein R = C ₁₂ to C ₁₈ alkyl or alkenyl group, AO = C ₂ to C ₄ oxyalkylene group, n = 5 or more integer) The method according to any one of claims 1 to 3, The alkylene diamine is any one selected from the group consisting of ethylene diamine, detramethylenediamine, hexamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine. The method of claim 2 or 3, The cationic surfactant is any one selected from the group comprising dodecyltrimethylammonium chloride, detradecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, dodecylbenzyldimethylammonium chloride and octadecyltrimethylammonium chloride Pickling additives. (a) 30% by weight of a condensate of dicyandiamide and formaldehyde satisfying formula 1 below and any polycondensate of alkylenediamine and epichlorohydrin satisfying formula 2 below, ; Formula 1 (HOCH ₂ ) nNRC (NH) NHCN (Where R = H when n = 1, and R = none when n = 2) Formula 2 Where R = alkylene group and n = integer (b) 20% by weight of alkylene diamines; (c) 0.5 to 1% by weight of a cationic surfactant satisfying the following Formula 3; And Formula 3 (Wherein R ₁ = long-chain alkyl group, R ₂ to R ₄ = C ₁ to C ₂ alkyl group, X = Br or Cl) (d) 0.5 to 1% by weight of a nonionic surfactant satisfying the formula (4) below; Formula 4 R-O- (A0) n-H (Wherein R = C ₁₂ to C ₁₈ alkyl or alkenyl group, AO = C ₂ to C ₄ oxyalkylene group, n = 5 or more integer) Pickling additive for inhibiting corrosion generated during pickling of the metal material, comprising an increase, and to increase the pickling rate. (1) Acid components selected from inorganic acids such as sulfuric acid, hydrochloric acid, phosphoric acid, sulfamic acid, hydrofluoric acid, nitric acid, and organic acids such as formic acid, glacial acetic acid, citric acid, tartaric acid, malic acid, and gluconic acid, or two or more mixed acid components selected from them on (2) An acid-cleaning composition of a metal material, wherein the pickling additive of claim 6 is added in an amount of 0.0001 to 5% by weight. (1) Acid components selected from inorganic acids such as sulfuric acid, hydrochloric acid, phosphoric acid, sulfamic acid, hydrofluoric acid, nitric acid, and organic acids such as formic acid, glacial acetic acid, citric acid, tartaric acid, malic acid, and gluconic acid, or two or more mixed acid components selected from them on (2) 0.0001 to 5% by weight of any one selected from the pickling additives of claim 1 to 3, wherein the pickling composition of a metal material.