KR100605718B1 - Degreasing Agent with Excellent Deforming and Cleaning - Google Patents

Abstract

The present invention relates to a degreasing agent for removing rolling oil or rust preventive oil, etc., present on the surface of a cold rolled steel sheet after a rolling process, wherein an aqueous solution obtained by mixing sodium hydroxide and builders in a weight ratio of 20: 1.5 to 6.5 is used as a first solution. 2 Based on the total weight of the solution, a solution obtained by mixing 5.0 to 9.0% by weight of a nonionic surfactant, 2.5 to 6.0% by weight of a stabilizer, 0.4 to 1.2% by weight of an organic chelating agent, and the remainder of the solvent is used as a second solution. A degreasing agent is provided by mixing a solution and a second solution in a weight ratio of 1: 0.020 to 1: 0.450. The degreasing agent thus provided is excellent in preventing defoaming and detergency as well as preventing environmental pollution.

Degreaser, antifoaming, detergency, cold rolled steel sheet

Description

Degreasing Agent with Excellent Deforming and Cleaning

1 is a graph measuring the amount of surface residual carbon of the steel sheet degreasing at the steel mill.

Figure 2 is a graph measuring the whiteness of the steel sheet degreasing at the steel mill.

The present invention relates to a degreasing agent for removing the rolled oil or rust preventive oil present on the surface of the cold rolled steel sheet after the rolling process, in particular, a degreasing agent having excellent antifoaming and detergency as well as preventing environmental pollution during removal of the rolled oil or rust preventive oil of the cold rolled steel sheet. It is about.

In general, rolled oil or rust preventive oil is applied to the surface of the cold rolled steel sheet subjected to the rolling process in the form of a film. Before the cold rolled steel sheet is introduced into the annealing furnace, a degreasing process must be carried out to remove the rolled oil. If degreasing is insufficient, various problems such as graphite precipitation, contamination in the furnace, adverse effects on chemical conversion, and deterioration of plating adhesion are required. This causes problems such as deterioration of the quality of the cold rolled steel sheet.

In order to solve this problem, various degreasing agents have been developed. For example, in Korean Patent No. 292287, degreasing, pickling, and rust prevention which can perform degreasing, pickling, and rust prevention in a single process when pickling ferrous or nonferrous structures. A one-component composition is disclosed, and the degreasing agent discloses polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, and the like as a surfactant component.

As described above, in the prior art, a non-ionic surfactant added to a degreasing agent is a degreasing agent in which a nonyl phenol compound is added. However, the nonyl phenol compound is regulated because it is harmful to humans as well as environmental pollution caused by residual phenol. Accordingly, there is a need for the development of a degreasing agent containing a nonionic surfactant that can replace it.

In order to solve this problem, the present invention is to provide an alkali degreasing agent to which a nonionic surfactant such as polyoxyethylene alkyl ether and polyoxypropylene alkyl ether is added. This is very excellent.

According to the invention,

Aqueous solution of sodium hydroxide and builders in a weight ratio of 20: 1.5 to 6.5 was used as the first solution, and 5.0 to 9.0 wt% of nonionic surfactant, 2.5 to 6.0 wt% of stabilizer based on the total weight of the second solution. A degreasing agent obtained by mixing a first solution and a second solution in a weight ratio of 1: 0.020 to 1: 0.450 by using a solution obtained by mixing 0.4 to 1.2% by weight of a chelating agent and the remaining solvent as a second solution.

In general, degreasing treatment is performed to remove the rolled oil or rust preventive oil present in the cold rolled steel sheet after the rolling process, and for the purpose of increasing the defoaming and cleaning effect of the degreasing agent used at this time, as well as surfactants and builders and chelating agents. It is preferable to use an additive in mixture with an alkali component suitably.

Hereinafter, the present invention will be described in more detail.

The present invention is to provide a degreasing agent excellent in defoaming and detergency for the degreasing treatment of cold-rolled steel sheet, the composition and ratio are as follows.

The degreasing agent according to the present invention is an aqueous solution obtained by mixing sodium hydroxide and builder in a weight ratio of 20: 1.5 to 6.5 as a first solution, and 5.0 to 9.0 wt% of a nonionic surfactant based on the total weight of the second solution, and a stabilizer. Mixing the first solution and the second solution in a weight ratio of 1: 0.020-1: 0.450 by using a solution obtained by mixing 2.5 to 6.0% by weight, 0.4 to 1.2% by weight of an organic chelating agent and the remaining solvent as a second solution. It is characterized by.

First, in the preparation of the first solution for the degreasing agent according to the present invention, it is preferable to mix the sodium hydroxide and the builder in a weight ratio of 20: 1.5 ~ 6.5. At this time, if the mixing ratio of the builders to sodium hydroxide 20 by weight ratio is less than 1.5, the dispersion effect and the re-contamination prevention effect is reduced, if the 6.5 or more there is a problem that precipitation occurs. The builder added to the first solution consists of sodium gluconate, sodium metasilicate, sodium orthosilicate, metapotassium silicate, pyrosodium phosphate, tetrasodium phosphate, tripolysodium phosphate, hexametasodium phosphate, potassium hydroxide and potassium carbonate At least one component selected from the group consisting of: and most preferably used builder is sodium gluconate.

The nonionic surfactant added to the degreasing agent of the present invention is preferably a nonionic surfactant having a M + N value of 5-20, which is a C6 to C18 fatty alcohol, and at this time, a C6 to C18 fatty alcohol. The nonionic surfactant used as the raw material is selected from polyoxyethylene alkyl ether and polyoxypropylene alkyl ether.

More specifically, the nonionic surfactant is

RO- (EO) _M (PO) _N H

Wherein R is alkyl, EO is an ethylene oxide group, PO represents a propylene oxide group, and the M + N value in the above formula is preferably from 5 to 20.

In addition, the amount of the nonionic surfactant added to the second solution of the degreasing agent is preferably 5.0 to 9.0% by weight, and when the amount is 5.0% by weight or less, the cleaning and dispersion penetrating effects are insignificant. There is a problem of deterioration and excessive foaming.

Stabilizers added to the degreasing agent for solubility, dispersibility and stabilization are selected from sodium naphthalenesulfonate, 1,2-benzylisotriazole and mixtures thereof, with the addition amount being preferably 2.5 to 6.0% by weight. If it is less than 2.5% by weight, the dispersion and rust preventive effect is reduced, and when it is more than 6.0% by weight, excessive bubbles are generated.

In addition, as the organic chelating agent added to the second solution of the degreasing agent according to the present invention, diethylenetriamine penta (methylphosphonic) acid sodium salt, (1-hydroxyethylidene) diphosphonic acid sodium salt or Mixtures of these are preferred. The amount of addition is preferably 0.4 to 1.2% by weight, when the 0.4% by weight or less, the chelating effect is reduced, when more than 1.2% by weight of corrosion occurs due to excessive Cl value.

In the second solution of the degreasing agent, the chelating agent is used as a metal ion blocking agent which forms a complex with metal ions to block the function of the metal ions, and the chelating agent is a compound containing two or more atoms having unshared electron pairs. Coordination bonds with to form a stabilized chelate ring resulting in increased stability.

In the preparation of the degreasing agent according to the present invention, sodium gluconate, sodium metasilicate, sodium orthosilicate, metapotassium silicate, pyrosodium phosphate, tetrasodium phosphate, tripolysodium phosphate, hexametadium phosphate, hydroxide as builders 1: 0.020-by weight weight ratio of the 2nd solution which consists of a nonionic surfactant, a stabilizer, an organic chelating agent, and remainder to the 1st solution which mixed at least 1 or more components chosen from the group which consists of potassium and potassium carbonate. It is preferable to mix as 1: 0.450. If the mixing ratio is out of the bubble generation suppression effect is reduced.

Further, in the field application of the degreasing solution in which the first solution and the second solution are mixed at a weight ratio of 1: 0.020 to 1: 0.450 as described above, the solvent is diluted to 1.0% to 3.5% based on the sodium hydroxide concentration. It is desirable to. At this time, water is most preferable as a solvent for dilution.

Thus, the degreasing agent prepared according to the present invention, unlike the prior art by using a non-ionic surfactant as a raw material of the natural alcohol-based, was not only environmental pollution prevention, but also excellent in anti-foaming and detergency when cleaning cold rolled steel sheet.

Hereinafter, the present invention will be described in detail with reference to the following examples, but the present invention is not limited thereto.

Example

Preparation Example 1

A mixed aqueous solution in which 20 g of sodium hydroxide and 4 g of sodium gluconate was dissolved in 100 g of water was prepared as a first solution. Independently, 88 ml of water, 7.4 g of polyoxyethylene methyl ether, 3.4 g of sodium naphthalene sulfonate, 0.4 g of diethylenetriamine pentamethylphosphonic acid sodium salt, and 0.4 g of (1-hydroxyethylidene) diphosphonic acid sodium salt It was dissolved to prepare a second solution. The degreasing solution was prepared by mixing 100 g of the first solution and 15 g of the second solution, and diluting the solution with water so as to obtain a NaOH concentration of 2.5% based on a commercially available product (product name: Strip Cleaner, Trileaf). And degreasing properties were compared.

Example 1

In general, degreasing treatment has been carried out in the steel mill under the same conditions as degreasing (alkaline degreasing) → (washing) → (electrolytic degreasing) → (washing).

In the case of electrolytic degreasing, the DC power supply of the rectifier was connected to the electrode and the specimen of the electrolytic degreasing device so that it could be energized. At this time, the positive electrode was applied to the specimen and the positive electrode was applied to the counter electrorod through the entire experimental procedure to generate hydrogen gas on the surface of the specimen and oxygen gas on the opposite electrode.

After degreasing, the amount of rolling oil present in the specimen was analyzed by the surface organic carbon analyzer. In addition, under the above conditions, the foaming and breaking time were measured at 60 ° C. and 85 ° C., respectively, to evaluate the defoaming properties of the degreasing solution.

In order to evaluate the properties of the degreasing solution, the amount of foam was measured by KSM 2709 method (Ross-Miles), and the emulsification dispersibility was evaluated by visual observation and the amount of oil remaining after degreasing.

Degreasing results of the degreasing specimen as described above are shown in Table 1 below.

division                                              Preparation Example 1                                              Existing Product                                              Degreasing (residual surface carbon mg / m ² )  1.8 ~ 4.3  11-13 Anti-foaming (degreaser with 1% rolled oil)                                               Suppression  Breakable  Suppression  Breakable Temperature 60 ℃ 46 seconds 29 minutes 46 seconds 1 hour 28 minutes 85 ℃ 34 seconds 36 minutes 30 seconds 1 hour 20 minutes

As shown in Table 1, the degreasing agent (Preparation Example 1) of the present invention has a very small amount of residual surface carbon compared to the existing degreasing agent products, it can be seen that the antifoaming is also very good.

Example 2

The degreasing treatment results in the steel mill are shown in Table 2, and the surface residual carbon amount and the whiteness are shown in Figs. Here, the D / S is the drive side of the cold rolled steel sheet, W / S was sampled from the work side of the cold rolled steel sheet to evaluate the degreasing properties, the same method as Example 1 The amount of organic carbon was analyzed (see FIG. 1), and the degreasing property was also evaluated by measuring the whiteness of the degreasing steel sheet (see FIG. 2). As shown in Table 2 and FIGS. 1 and 2, the lower the amount of residual surface carbon and the higher the value of whiteness, the better the degreasing property.

division Preparation Example 1 Existing Product Degreasing (residual surface carbon mg / m ² ) 3.1 ~ 5.9 7.0-10.5 Whiteness 93-96 82-88

As shown in Table 2, the degreasing agent of the present invention was very low compared to the conventional degreasing agent, the amount of residual surface carbon, it can be seen that the degreasing properties in the steel mill actually producing cold rolled steel sheet.

Using the degreasing agent according to the present invention can remove the rolled oil or rust preventive oil present in the cold rolled steel sheet after the rolling process, thereby providing a degreasing agent excellent in anti-foaming and detergency.

Claims (7)

Aqueous solution of sodium hydroxide and builders in a weight ratio of 20: 1.5 to 6.5 was used as the first solution, and 5.0 to 9.0 wt% of nonionic surfactant based on the total weight of the second solution, sodium naphthalenesulfonate, 1,2- 2.5-6.0 wt% stabilizer selected from benzylisotriazole or mixtures thereof, diethylenetriamine penta (methylphosphonic) acid sodium salt, (1-hydroxyethylidene) diphosphonic acid sodium salt Or a solution obtained by mixing 0.4 to 1.2% by weight of an organic chelating agent selected from a mixture thereof and the remainder of the solvent as a second solution, and the first solution and the second solution in a weight ratio of 1: 0.020 to 1: 0.450. A degreasing agent excellent in defoaming and detergency, characterized by mixing. The method of claim 1, wherein the builder is sodium gluconate, sodium metasilicate, sodium orthosilicate, metapotassium silicate, pyrosodium phosphate, tetrasodium phosphate, tripolysodium phosphate, hexamethodium phosphate, potassium hydroxide, and potassium carbonate. A degreasing agent excellent in anti-foaming and detergency, characterized in that it is at least one component selected from the group consisting of. The degreasing agent of claim 1, wherein the nonionic surfactant is selected from polyoxyethylene alkyl ethers and polyoxypropylene alkyl ethers. The method of claim 1 or 3, wherein the nonionic surfactant is RO- (EO) _M (PO) _N H Wherein R is alkyl, EO is an ethylene oxide group, and PO is a propylene oxide group, and the value of M + N is in the range of 5-20. . delete delete The degreasing agent according to claim 1, wherein the degreasing agent is diluted to 1.0% to 3.5% based on sodium hydroxide concentration using a solvent.

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