JP5824319B2 - Rust removal / rust prevention agent and removal / rust prevention method - Google Patents

Description

  The present invention relates to a rust and rust preventive agent that removes rust generated after pickling of steel materials and prevents further rust generation, and also relates to a rust and rust preventive method for steel materials using the rust preventive agent.

  An oxide film (scale, rust) adheres to the surface of steel materials such as steel plates, rods, and wires, and this oxide film is removed for use in subsequent processing, plating, coating, and other processes. There is a need to. For this purpose, washing with an inorganic acid such as hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid or phosphoric acid, or an organic acid such as citric acid, hydroxyacetic acid, formic acid, malic acid, oxalic acid or gluconic acid is generally used. . In this washing step, steps such as (1) acid washing, (2) water washing, (3) rust prevention, and (4) drying are employed.

  In Patent Document 1, the steel material is washed with a phosphonic acid-based cleaning liquid adjusted to a pH of 5.5 to 7.5 instead of acid cleaning, and after removing the scale, the cleaning liquid is adjusted to pH 8.0 to 9.5. It is described that the rust-proofing treatment of the steel material is performed by adjusting to the above range.

JP-A-9-3670

  In the method of Patent Document 1, when the scale is formed relatively firmly on the steel material, the cleaning liquid having a pH of 5.5 to 7.5 does not have sufficient descaling, and the pH after cleaning is 8.0. If the operation of adjusting the pH to ~ 9.5 and adjusting the pH to 5.5 to 7.5 again after rust prevention treatment is repeated, the liquid tends to deteriorate, and if the amount of cleaning liquid is large, the pH is adjusted quickly and uniformly. There are problems such as difficult things.

  Moreover, when processing separately the cleaning liquid adjusted to pH 5.5 to 7.5 and the antirust treatment liquid adjusted to pH 8.0 to 9.5, the number of steps increases, the cleaning liquid The steel material is immersed in the rust prevention treatment liquid with the adhesion of the material, resulting in a large variation in pH near the surface of the object to be treated, and the pH control of the treatment liquid is complicated and there is a problem that the rust prevention effect varies. .

  On the other hand, when the conventional process (above (1) to (4)) is adopted to completely perform descaling, the surface becomes more active as the descaling is completely performed, and a new one immediately after cleaning. Since rust is generated, it is necessary to perform a rust removal treatment, and it is necessary to perform a rust prevention treatment so as not to generate rust until it is used in a process after the cleaning process.

  The object of the present invention is to provide a rust removal and rust preventive agent that has both a rust removal function for removing rust generated after pickling of steel with a pickling solution and a rust prevention function for preventing the occurrence of rust after removal in a single solution. Is to provide. Moreover, it is providing the method of performing the rust removal rust prevention process of steel materials using such a rust removal rust prevention agent.

The present invention relates to a rust-preventing rust inhibitor that removes rust generated after pickling of steel with a pickling solution and prevents the occurrence of rust after removal, and is a hydroxyalkyliminocarboxylic acid represented by the following formula (1) If, as a chelating agent, derusting rust agent characterized in that it comprises citric acid and gallic acid, and water.
R ₂ COOH
_{HO-R 1 -N <(1} )
R ₃ COOH
(Wherein R ₁ , R ₂ and R ₃ are the same or different and each represents an alkylene group having 1 to 5 carbon atoms) .

  Moreover, this invention provides the said rust removal rust preventive agent which contains a phosphate further in the said rust removal rust preventive agent.

  Moreover, this invention provides the said rust removal rust preventive agent whose said hydroxyalkyliminocarboxylic acid is hydroxyethyliminodiacetic acid.

  Moreover, this invention provides the said rust removal antirust agent whose said phosphate is sodium tripolyphosphate.

Or The present invention provides a rust removal rust inhibitor of the described obtained by adjusting the pH to 6-8.

Furthermore, the present invention provides a method for removing rust and rust of a steel material, wherein the steel material is pickled with a pickling solution, and then the steel material is brought into contact with the rust and rust preventive agent described above.
Moreover, this invention provides the said rust removal rust prevention method whose pickling liquid is a sulfuric acid pickling liquid.

According to the present invention, a hydroxyalkyliminocarboxylic acid represented by the following formula (1) :
R ₂ COOH
_{HO-R 1 -N <(1} )
R ₃ COOH
(Wherein R ₁ , R ₂ and R ₃ are the same or different and each represents an alkylene group having 1 to 5 carbon atoms.)
As a chelating agent, and citric acid and gallic acid, by immersing the steel material after pickling treatment solution containing water, the surface to remove the rust formed on the surface of the steel with one solution Can be modified to a surface having an antirust effect.

Rust removal rust inhibitor of the present invention contains a hydroxyalkyl imino acid represented by the following formula (1), and a chelating agent, and citric acid and gallic acid, and water.
R ₂ COOH
_{HO-R 1 -N <(1} )
R ₃ COOH
_{(Wherein, R 1, R 2, R} 3 are the same or different, each represents an alkylene group having 1 to 5 carbon atoms.) Hydroxyalkyl imino carboxylic acid, and a chelating agent, citric acid and gallic acid And water.

In the general formula (I), examples of the alkylene group represented by R ₁ , R ₂ , and R ₃ include a methylene group, an ethylene group, a propylene group, a butylene group, and a pentylene group.

  Specific examples of the compound represented by the general formula (I) include, for example, hydroxyethyliminodiacetic acid, hydroxypropyliminodiacetic acid, hydroxybutyliminodibutyric acid, hydroxypentyliminodivaleric acid and the like. Of these, hydroxyethylcarboxylic acid is preferred, and hydroxyethyliminodiacetic acid is most preferred.

  The hydroxyalkyliminocarboxylic acid may be free or a salt.

  Examples of the salt of hydroxyalkyliminocarboxylic acid include salts with alkali metals such as sodium, potassium and lithium, and salts with alkali metals such as calcium and magnesium.

  The amount of the hydroxyalkyliminocarboxylic acid contained in the rust and rust preventive agent of the present invention is 1 to 30%, preferably 10 to 25%, based on the entire rust and rust preventive agent. If the amount of hydroxyalkyliminocarboxylic acid in the rust and rust preventive agent is less than 1%, the rust and rust preventive effect is not sufficient, and if it exceeds 30%, the effect is not improved, which is not preferable.

Combination of citric acid and gallic acid chelating agent used in the present invention is good Masui order to be observed synergy Josabibosabi effects.

  The amount of the chelating agent contained in the antirust agent of the present invention is preferably 1 to 60 parts by weight, particularly 30 to 50 parts by weight, based on 100 parts by weight of hydroxyalkyliminocarboxylic acid. .

  When the amount is less than 1 part by weight, the effect of removing rust is not sufficient, and when it is more than 50 parts by weight, the effect is diminished by interaction with other components.

In removing rust corrosion inhibitor of the present invention, the formula (1) with hydroxyalkyl imino acids (hereinafter, simply referred to as hydroxyalkyl imino acids), denoted, as a chelating agent, citric acid and gallic acid (hereinafter These two acids are simply referred to as a chelating agent) and water to add phosphate to further enhance the derusting and rust prevention effect.

  Examples of such phosphates include salts of phosphoric acid and alkali metals. Examples of phosphoric acid include phosphoric acid (orthophosphoric acid), phosphorous acid, hypophosphorous acid, polyphosphoric acid, metaphosphoric acid, Examples thereof include phosphoric acid compounds having a phosphate skeleton such as pyrophosphate. Examples of the salt include alkali metal salts such as potassium and sodium.

  Specific examples of the phosphate include sodium tripolyphosphate, sodium pyrophosphate, sodium phosphate, sodium hydrogen phosphate, sodium dihydrogen phosphate, sodium tetrapolyphosphate, sodium pentapolyphosphate, sodium phosphite, Examples thereof include sodium hypophosphite, sodium hexametaphosphate, potassium phosphate, potassium hydrogen phosphate, and potassium dihydrogen phosphate. Of these, sodium tripolyphosphate is particularly preferable.

  These phosphates may be used individually by 1 type, and may use 2 or more types together.

  The amount of phosphate contained in the derusting and rust preventive is 30 to 100 parts by weight, preferably 60 to 80 parts by weight, based on 100 parts by weight of hydroxyalkyliminocarboxylic acid. If the amount is less than 30 parts by weight, the contribution to the rust removal and rust prevention effect is not sufficient, and if it exceeds 100 parts by weight, the effect is diminished by interaction with other components, which is not preferable.

  The antirust agent of the present invention is prepared by mixing and dissolving hydroxyalkyliminocarboxylic acid, a chelating agent, and optionally phosphate and water, and adjusting the pH to 6 to 8 as necessary. Can be manufactured.

  The pH adjustment may be performed by adding a pH adjuster to a solution in which each component is dissolved, and examples of the pH adjuster include alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine, morpholine, piperazine, and hexamine. And cyclic amines.

  The mixing of these components is not particularly limited. For example, other components may be added to water in a predetermined amount while stirring at room temperature and stirred.

  The concentration of the mixture at this time may be such that the total amount of each component is about 10 to 200 parts by weight with respect to 100 parts by weight of water. Can be used diluted.

  Moreover, the rust removal rust prevention method of this invention can be implemented by making this steel material contact said rust removal rust prevention agent, after pickling a steel material with a pickling liquid.

  In the method of the present invention, pickling solutions for pickling steel materials include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, phosphoric acid, citric acid, hydroxyacetic acid, formic acid, malic acid, oxalic acid, gluconic acid, etc. And an aqueous solution of an organic acid.

  In the method of the present invention, in particular, after pickling with an inorganic acid such as hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, phosphoric acid, etc., the rust and rust preventive agent of the present invention is brought into contact with the steel material, thereby preferably removing rust and rust. The effect is obtained, and particularly preferable results are obtained when the rust and rust preventive treatment is performed with the rust and rust preventive agent of the present invention after washing with sulfuric acid.

  Examples of the steel material pickled with the pickling solution include steel plates, rods, and wire rods, and these steel materials can be used in any shape. The surface of these steel materials is covered with scale (surface oxide) by heat treatment, rust at room temperature, and the like.

  When performing sulfuric acid pickling, a sulfuric acid solution having a concentration of 5 to 30% is prepared, and a steel material is immersed in this solution. The immersion temperature is 20 to 80 ° C., and the immersion time is about 10 to 60 minutes. By this pickling treatment, the surface of the steel material can be descaled to remove rust and dirt.

  After pickling, the surface is washed with water using a high pressure shower or the like to remove the remaining pickling solution on the surface. The surface of the steel material is active because oxides and the like are removed by pickling, and the surface is easily oxidized by water and the like, and water rust is generated. For this reason, it is necessary to remove newly generated water rust and to carry out rust prevention treatment so that rust does not occur.

  The steel material after pickling can be brought into contact with the rust and rust preventive by immersing the steel material after pickling in the rust and rust preventive solution of the present invention adjusted to a predetermined concentration.

  At this time, although the density | concentration of the derusting rust preventive agent of this invention is not restrict | limited in particular, Preferably it is 0.5 to 5.0%, and the pH of a derusting rust preventive agent is 6-8. Moreover, the rust removal and rust prevention of the steel material after pickling can be performed suitably by making immersion temperature into room temperature-40 degreeC, and making immersion time into 30 to 100 second.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by this. In the examples and comparative examples,% of the treatment liquid represents% by weight.

Example 1
(1) Preparation of Rust and Rust Preventive Agent In 100 parts by weight of water, 23.4 parts by weight of hydroxyethyliminodiacetic acid (manufactured by Kanto Chemical Co., Inc.) was dissolved while stirring at room temperature, and then sodium tripolyphosphate ( Kanto Chemical Co., Ltd.) 16.2 parts by weight was added and dissolved, and citric acid (Kanto Chemical Co., Ltd.) 9.0 parts by weight and gallic acid monohydrate (Kanto Chemical Co., Ltd.) 0.9 parts by weight as a chelating agent Was added and dissolved, and diethanolamine (manufactured by Kanto Chemical Co., Inc.) was added to adjust the pH of the solution to 7.2.
Subsequently, it diluted with water so that the sum total of each component might be 1%, and the antirust agent was obtained.

(2) Rust removal and rust prevention treatment of pickled steel material Concentrated sulfuric acid (98%) was diluted with water to prepare a 15% sulfuric acid solution, which was used as a sulfuric acid pickling solution. A steel material (steel plate, 50 mm long, 30 mm wide, 0.5 mm thick) was immersed in the above sulfuric acid pickling solution maintained at 60 ° C. for about 36 minutes, and then washed with water.

  This steel material was left in the air at a temperature of 50 ° C. and a humidity of 95% for 1 day, and then immersed in the above-mentioned (1) rust and rust inhibitor for 45 seconds at room temperature. The state of rust generation before immersion was a state in which rust was observed in 50% or more of the area of the steel sheet. Evaluation of the rust removal rust preventive agent after immersion evaluated the rust removal and the rust prevention state by the following method. These results are shown in Table 1.

Example 2
A rust and rust preventive was produced in the same manner as in Example 1 except that the concentration of the rust and rust preventive was changed to 0.5%, and a rust and rust preventive treatment was performed using this. The results are shown in Table 1.

Example 3
A rust and rust preventive was produced in the same manner as in Example 1 except that the concentration of the rust and rust preventive was 2.0%, and a rust and rust preventive treatment was performed using this. The results are shown in Table 1.

Example 4
A derusting and rust preventive agent was produced in the same manner as in Example 1 except that 14 parts by weight of hydroxyethyliminodiacetic acid was used as the hydroxyalkyliminocarboxylic acid, and a derusting and rustproofing treatment was performed using this. The results are shown in Table 1.

Example 5
A rust and rust preventive was produced in the same manner as in Example 1 except that sodium phosphate tripolyphosphate was not blended, and a rust and rust preventive treatment was performed using this. The results are shown in Table 1.

Comparative Example 4
A rust and rust preventive was produced in the same manner as in Example 1 except that the chelating agent was not included in gallic acid and only citrate was used. The results are shown in Table 1.

Comparative Example 5
A rust and rust preventive was produced in the same manner as in Example 1 except that citric acid was not included as a chelating agent and only gallic acid was used, and a rust and rust preventive treatment was performed using this. The results are shown in Table 1.

Comparative Example 1
Except not including hydroxyethyliminocarboxylic acid, hydroxyethyliminodiacetic acid, a rust and rust preventive was produced in the same manner as in Example 1, and a rust and rust preventive treatment was performed using this. The results are shown in Table 1.

Comparative Example 2
A rust and rust preventive was produced in the same manner as in Example 1 except that the chelating agent was not included, and a rust and rust preventive treatment was performed using this. The results are shown in Table 1.

Comparative Example 3
A rust and rust preventive agent was produced in the same manner as in Example 1 except that it did not contain a phosphate and a chelating agent, and a rust and rust preventive treatment was performed using this. The results are shown in Table 1.

<Evaluation>
(Evaluation of rust removal state)
Immediately after dipping in a rust and rust preventive agent at room temperature for 45 seconds after washing with sulfuric acid and washing with water, the rust removal state was visually evaluated.
◎ No rust is observed.
○ Slight rust is observed.
Δ Rust is observed in 10 to 20% of the area of the steel sheet.
X Rust is observed in 50% or more of the area of the steel sheet.

(Rust evaluation)
After being immersed in a derusting and rust preventive agent, after being left in the air at a temperature of 50 ° C. and a humidity of 95% for 1 day, the state of occurrence of rust was visually evaluated. In addition, about the generation | occurrence | production state of rust, when rust remains after rust removal, it is total evaluation of the remaining rust and newly generated rust.
◎ No rust is observed.
○ Slight rust is observed.
Δ Rust is observed in 10 to 20% of the area of the steel sheet.
X Rust is observed in 50% or more of the area of the steel sheet.

Claims (7)

A rust removal rust preventive agent that removes rust generated after pickling of steel with a pickling solution and prevents rust generation after removal, and a hydroxyalkyliminocarboxylic acid represented by the following formula (1) and a chelating agent and a, derusting rust agent characterized in that it comprises citric acid and gallic acid, and water.
R ₂ COOH
_{HO-R 1 -N <(1} )
R ₃ COOH
(Wherein R ₁ , R ₂ and R ₃ are the same or different and each represents an alkylene group having 1 to 5 carbon atoms.)   Furthermore, phosphate is included, The rust removal rust preventive agent of Claim 1 characterized by the above-mentioned.   The rust and rust preventive agent according to claim 2, wherein the phosphate is sodium tripolyphosphate.   The rust and rust preventive agent according to any one of claims 1 to 3, wherein the hydroxyalkyliminocarboxylic acid is hydroxyethyliminodiacetic acid. pH is adjusted to 6-8, The rust removal rust preventive agent of any one of Claims 1-4 characterized by the above-mentioned. A method for removing rust and rust of a steel material, comprising: pickling the steel material with a pickling solution and then bringing the steel material into contact with the rust and rust preventive agent according to any one of claims 1 to 5 . The method for removing rust and rust according to claim 6 , wherein the pickling solution is a sulfuric acid pickling solution.