KR101277940B1 - Blackened steel stheet with high adhesion property of blackened layer and surface appearance, and method for manufacturing the same - Google Patents

Abstract

The present invention is to provide a black steel sheet with improved blackening layer adhesion, excellent surface appearance, and to provide a method for easily and eco-friendly manufacturing.
To this end, the present invention is a zinc or zinc-based alloy plated steel sheet;
Ni layer formed on the surface of the zinc or zinc-based alloy plated steel sheet; And
It provides a black steel sheet excellent in blackening layer adhesion including a blackening layer formed on the Ni layer and a method of manufacturing the same.

Description

BLACK STEEL STHEET WITH HIGH ADHESION PROPERTY OF BLACKENED LAYER AND SURFACE APPEARANCE, AND METHOD FOR MANUFACTURING THE SAME}

The present invention relates to a black steel sheet and a method for manufacturing the same, which are applied to electronic appliances, home appliances, sound equipment, OA devices, and the like, and more particularly, a black steel sheet having improved adhesion and surface appearance of a blackening layer and an easy and eco-friendly method. It relates to a manufacturing method that can be prepared by.

Black steel sheet is a colored steel sheet with an inorganic black film formed on the surface of the steel sheet through blackening treatment, which can reduce the manufacturing cost because the coating process of the demand is omitted, and the black surface shape is uniform and beautiful, so it is the latest home appliances and sound equipment. It is used in various fields such as OA equipment, automotive parts, and the like, and its use is expanding recently.

Such a black steel sheet has been manufactured by a method of forming a black film through an oxidation method, an anodization process, or a chemical conversion process using a conventional zinc alloy plated steel sheet, mainly Zn-Ni alloy plated steel sheet. Typically, Japanese Patent Laid-Open No. 61-291981 and Japanese Patent Laid-Open No. 1990-282485 use acidic aqueous solutions containing metal ions such as Ni, Co, Fe, Al, Mg, Cu, Sn, C, Cr, Mo, and Ag. The method for forming a black film on a zinc alloy plated steel sheet through an oxidation method is disclosed.

In addition, Japanese Patent Laid-Open Nos. 62-263995 and 6-346288 disclose a method of forming a black film by cathodic treatment of an ordinary steel sheet or a surface-treated steel sheet in an aqueous solution, and Japanese Patent Laid-Open Nos. 63-161176 and Japan Japanese Patent Laid-Open No. 62-290880 discloses a method of forming a black film by chemically treating a zinc or zinc alloy plated steel sheet in a solution containing metal ions.

However, these prior arts have a problem in that the cost increases due to the formation of a black film by an anode method or an oxidation method using a zinc alloy plated steel sheet, and even if the galvanized steel sheet is chemically treated, blackening is caused due to a decrease in adhesion of the blackening layer. There is a drawback in that the powdering phenomenon in which the layer breaks or falls off is severe. In fact, Japanese Patent Application Laid-Open No. 1990-093077 discloses a method of forming a black film on a zinc or zinc-based alloy plated steel sheet using a solution containing Sn and Ni or Co compounds, but in the case of the blackened layer according to the manufacturing method , The powdering is so severe that the adhesion of the blackening layer is inferior.

In addition, the solution composition of the conventional blackening treatment technology mainly consists of three or more components, the composition is complicated, difficult to manage the solution during operation, and difficult to treat wastewater, including harmful components such as chromium, heavy metals and strong acids And environmental pollution.

One aspect of the present invention is to provide a black steel sheet with improved blackening layer adhesion of the zinc-based galvanized steel sheet, excellent surface appearance, and to provide a method for easily and eco-friendly manufacturing.

The present invention is a zinc or zinc-based alloy plated steel sheet;

Ni layer formed on the surface of the zinc or zinc-based alloy plated steel sheet; And

It provides a black steel sheet excellent in blackening layer adhesion and surface appearance including a blackening layer formed on the Ni layer.

In addition, the present invention comprises the steps of attaching Ni to the surface of the zinc or zinc-based alloy plated steel sheet to form a Ni layer;

It provides a method for producing a black steel sheet excellent in blackening layer adhesion and surface appearance comprising the step of forming a blackening layer by performing a blackening treatment on the steel sheet having the Ni layer.

According to the present invention, by suppressing the powdering (phendering) generated during the blackening process to improve the adhesion of the blackening layer and excellent surface appearance can be produced a black steel sheet with high price competitiveness. In addition, since it is possible to prevent the roll (roll) contamination by powdering in the manufacturing process, it is possible to improve the continuous workability and also to improve the adhesion of the resin layer during the protective resin coating process. In addition, the blackening treatment solution can be easily prepared, the solution management during the operation, there is an advantage that the environment-friendly manufacturing is possible.

1 is a cross-sectional view showing an example of the black steel sheet of the present invention.

Hereinafter, the present invention will be described in detail. The inventors of the present invention print that the chemical form and surface structure of the blackening layer act as important factors in order to improve the blackening layer adhesion while maintaining sufficient blackness, and for this purpose, it is important to set appropriate blackening treatment solution and treatment process conditions. It was recognized that the present invention has been achieved.

First, the black steel sheet of this invention is demonstrated in detail.

The black steel sheet of the present invention includes a zinc or zinc-based alloy plated steel sheet, a Ni layer formed on the surface of the zinc or zinc-based alloy plated steel sheet, and a blackening layer formed on the Ni layer.

The zinc or zinc-based alloy plating is not formed by a special method, it is sufficient that it is formed by a conventional method in the art.

The said Ni layer is formed by the Ni adhesion process mentioned later. It is preferable that the said Ni layer is attached by the adhesion amount of 50 mg / m <2> or more.

The blackening layer includes a metal oxide or a metal hydroxide and a mixture thereof. The metal oxide and the metal hydroxide may be mainly Ni oxide, Ni hydroxide, Zn oxide and Zn hydroxide. The blackening layer is formed by chemical conversion treatment (immersion, spraying, etc.) with the blackening treatment solution proposed in the present invention.

Unlike the blackening layer obtained by the conventional chemical conversion treatment by the blackening treatment solution containing metal ions, the black steel sheet of the present invention does not precipitate metal oxide in particulate form, and thus has a blackening layer formed by oxidizing the deposited metal surface. The blackening layer adhesion problem (desorption phenomenon of the precipitated particles, powdering), which was a problem in the chemical conversion treatment, is greatly improved. In addition, the blackening treatment solution proposed in the present invention, unlike the solution consisting of three or more components of the prior art, because it is simple in the composition of a minimum of two components and does not contain harmful components, waste water treatment is easy and environmentally friendly black steel sheet It can provide a manufacturing method of.

The black steel sheet of this invention further contains a resin layer on the said blackening layer. The resin layer is formed of a coating of a protective resin, the protective resin is a protective resin mainly used for polyurethane-based water-soluble coating material, it is not particularly limited in its type can be used both water-soluble or solvent type.

In addition, the black steel sheet of the present invention may further include an undercoat layer of organic, inorganic, or organic / inorganic mixed system for securing physical properties such as resin adhesion, corrosion resistance and processability between the resin layer and the blackening layer. The undercoat may be one or more layers.

Hereinafter, the manufacturing method of the black steel sheet of the present invention will be described in detail.

First, Ni is attached to the surface of the zinc or zinc-based alloy plated steel sheet to form a Ni layer. The method of attaching Ni is not particularly limited, and examples thereof include electroplating, vacuum deposition plating, electroless plating using a reducing agent, and substitution plating. Preferably, Ni flash using an electroplating method that can form a dense Ni layer while using existing equipment is used.

It is preferable that the adhesion amount at the time of adhesion of said Ni is 50 mg / m <2> or more. This is because when the amount of Ni deposited is less than 50 mg / m 2, the amount of Ni for forming the blackening layer is not sufficient, so that sufficient blackness cannot be obtained during the blackening treatment. Although the upper limit of the said adhesion amount is not specifically limited, It is more preferable not to exceed 500 mg / m <2> in consideration of economics, such as a production cost.

The blackening process is performed to the steel plate which has the said Ni layer, and a blackening layer is formed. The blackening treatment is performed using a blackening treatment solution of a minimum two-component system containing 5-50 g / l of an organic acid and 5-100 g / l of an inorganic acid, and metal ions and other additives may be added if necessary.

The organic acid may be acetic acid, citric acid, tartaric acid, malic acid, oxalic acid, phthalic acid, maleic acid, or the like. The reason for adding the organic acid is to lower the solution pH, oxidize the Zn of the Ni layer or the galvanized layer to form a blackening layer in the form of Ni oxide, Ni hydroxide, Zn oxide or Zn hydroxide, and solution stability (elution is performed during blackening treatment. To form a complex with the metal ions coming out to prevent precipitation by hydrolysis of the metal ions) and to form a uniform surface appearance. If the content of the organic acid is less than 5g / l oxidizing power is not enough sufficient blackness can not be obtained, at the same time solution stability is lowered by the occurrence of precipitation in the solution, if the content exceeds 50g / l surface appearance ( Blackness) and blackening layer adhesion becomes poor, and cost is not economical.

The type of the inorganic acid ions _{^{NO 3 -, SO 4 2-,}} PO 4 3-, Cl -, ClO 3 -, ClO 4 - and the like can be used. The inorganic acid ion is a blackening layer formation accelerator, it is preferable that the content is 5 ~ 100g / l, if the content is less than 5g / l not only sufficient blackness can be obtained, but also the rate of blackening layer formation is slow, practical application If this is difficult and exceeds 100 g / l, the surface reaction (blackness) and blackening layer adhesion are poor due to overreaction, and the cost is not economical.

The blackening solution is a metal such as Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Sn ²⁺ , Sb ²⁺ Ti ²⁺ , Al ³⁺ , Cu ²⁺ , Mo ²⁺ , V ³⁺ , Mn ²⁺ It may further include ions, and may further include a solution stabilizer, a complexing agent, an oxidation promoter, and the like as an additive.

The pH of the blackening treatment solution is preferably set to 1.5 ~ 4.0. If the pH is less than 1.5, the oxidizing power is stronger, so that the Ni layer or zinc-based plating layer dissolves more severely than the blackening layer formation, and when the pH is higher than 4.0, the oxidizing power is not only degraded, but solution stability is caused by precipitation due to hydrolysis of the eluted metal ions. It is not desirable because it falls.

In the present invention, further comprising the step of forming a resin layer on the blackening layer. The resin layer protects the blackening layer and is for securing physical properties such as corrosion resistance and workability. The kind of the resin layer is not particularly limited, and both water-soluble and solvent-type can be used, and preferably a water-soluble coating material of polyurethane type.

In addition, the present invention may further form an undercoat layer of an organic, inorganic or organic / inorganic mixed system in order to secure physical properties such as resin adhesion, corrosion resistance and processability between the blackening layer and the resin layer.

Hereinafter, embodiments of the present invention will be described in detail. The following examples are only for the understanding of the present invention, but the present invention is not limited thereto.

An example of the film structure of the black steel sheet according to the manufacturing process of the present invention is shown in FIG. As shown in FIG. 1, a Ni layer 2 is formed on a steel sheet on which a zinc or zinc alloy plated layer 1 is formed, and then a blackening layer 3 is formed through blackening. In addition, the resin layer 4 may be formed, and an organic, inorganic, or organic / inorganic mixed base coat layer 5 may be further formed between the blackening layer 3 and the resin layer 4.

(Example)

Ni flash plating was carried out using an electrogalvanized steel sheet having a zinc adhesion amount of 20 g / m 2 to have an Ni adhesion amount shown in Table 1 below, followed by blackening treatment using the solution composition of Table 1 to prepare a black steel sheet. The blackening treatment was used for 4 seconds immersion treatment.

The blackening treatment evaluation of the black steel sheet thus prepared was measured in the surface appearance and powdering and the results are shown in Table 1. Surface appearance measured the whiteness (L *) using a color difference meter, and the closer to 0, the higher the blackness. Powdering evaluation was performed by observing blackening particles which fall off on the adhesive surface by strongly attaching and detaching the adhesive surface of the cellophane tape to the blackening layer.

In order to quantify the powdering properties, the whiteness (Lp) of the powdered portion was measured using a color difference meter, and the closer to the Lp value of the untreated sample, 88.92, the less powdering occurred.

division Ni adhesion amount Blackening solution Evaluation results (Mg / ㎡) Citric acid NO ₃ ^- Surface appearance (L *) Powder Ring (Lp) Comparative Example 1 30 30 50 35.53 88.82 Comparative Example 2 30 3 3 48.25 88.37 Comparative Example 3 30 3 20 45.17 87.95 Comparative Example 4 30 15 15 37.24 88.75 Inventory 1 50 5 5 33.06 88.59 Inventive Example 2 70 10 100 31.78 88.78 Inventory 3 100 20 20 31.31 88.9 Honorable 4 200 20 80 29.17 87.98 Inventory 5 250 30 30 30.61 88.37 Inventory 6 300 30 50 29.53 88.93 Honorable 7 350 40 20 30.34 88.31 Inventive Example 8 400 40 80 28.72 87.56 Proposition 9 450 50 5 31.22 88.48 Inventory 10 500 50 100 26.94 86.13 Comparative Example 5 500 50 150 26.72 82.69 Comparative Example 6 500 100 100 24.95 79.56 Comparative Example 7 500 150 50 24.21 80.33 Comparative Example 8 500 30 150 26.47 82.12

As shown in Table 1, the inventive examples show that L * shows a degree of blackness of about 30, and also has excellent powdering property (Lp). However, when Ni adhesion amount is less than 50 mg / m <2> or citric acid and ammonium nitrate are less than 5 g / l like Comparative Examples 1-4, blackening layer adhesiveness is favorable but sufficient blackness is not obtained. In addition, as shown in Comparative Examples 5 to 8, when citric acid and ammonium nitrate exceeded 50 g / l and 100 g / l, respectively, the blackness was good, but the blackening layer adhesion was inferior.

On the other hand, using Inventive Example 3 in Table 1, after performing Ni flash, blackening treatment and resin coating, the whiteness (L *) was evaluated and shown in Table 2. The protective resin at this time is a polyurethane-based water-soluble coating material.

division Ni flash Blackening Resin coating Whiteness (L *) 47.52 31.31 25.75

As shown in Table 2, when the blackened steel sheet of the present invention is coated with a protective resin, it can be seen that the whiteness is further lowered to obtain an excellent surface appearance.

1 ..... zinc or zinc alloy plating 2 ..... Ni layer
3 ..... black layer 4 ..... resin layer
5 ..... coating layers of organic, inorganic or mixed systems

Claims (15)

Zinc or zinc-based alloy plated steel sheet;
Ni layer formed on the surface of the zinc or zinc-based alloy plated steel sheet; And
Blackening layer formed on the Ni layer
It includes, the blackening layer is a black steel sheet excellent in blackening layer adhesion and surface appearance that is formed by blackening treatment with a blackening treatment solution containing 5 ~ 50g / l, organic acid ions 5 ~ 100 g / l.
The method according to claim 1,
The Ni layer is a black steel sheet excellent in blackening layer adhesion and surface appearance that is formed by being attached with an adhesion amount of 50 mg / ㎡ or more.
The method according to claim 1,
The blackening layer is a black steel sheet excellent in blackening layer adhesion and surface appearance including at least one selected from the group consisting of Ni oxide, Ni hydroxide, Zn oxide and Zn hydroxide.
The method according to claim 1,
The black steel sheet excellent in blackening layer adhesiveness and surface appearance which further contain a resin layer on the said blackening layer.
The method of claim 4,
The black steel sheet excellent in blackening layer adhesiveness and surface appearance further including the undercoat layer of organic type, inorganic type, or organic / inorganic type system between the said blackening layer and resin layer.
Attaching Ni to the surface of the zinc or zinc-based alloy plated steel sheet to form a Ni layer;
Blackening the steel sheet having the Ni layer to form a blackening layer
Lt; / RTI &gt;
The blackening treatment is a method for producing a black steel sheet excellent in blackening layer adhesion and surface appearance is carried out using a blackening treatment solution containing 5 ~ 50g / l, organic acid ions 5 ~ 100 g / l.
delete The method of claim 6,
The Ni adhesion amount is 50mg / ㎡ or more blackening layer adhesion method and manufacturing method of the black steel sheet excellent in surface appearance.
The method of claim 6,
The organic acid is a method for producing a black steel sheet excellent in blackening layer adhesion and surface appearance of acetic acid, citric acid, tartaric acid, malic acid, oxalic acid, phthalic acid and maleic acid.
The method of claim 6,
The inorganic acid ions _{^{NO 3 -, SO 4 2-,}} PO 4 3-, Cl -, ClO 3 - , and ClO ₄ ^- 1 jong or more blackening layer adhesion and surface appearance The method of producing a superior black steel sheet of the.
The method of claim 6,
The blackening solution is one of Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Sn ²⁺ , Sb ²⁺ Ti ²⁺ , Al ³⁺ , Cu ²⁺ , Mo ²⁺ , V ³⁺ and Mn ²⁺ The method for producing a black steel sheet excellent in blackening layer adhesion and surface appearance further comprising the above metal ions.
The method of claim 6,
The blackening treatment solution is a method for producing a black steel sheet excellent in blackening layer adhesion and surface appearance that may further include one or more of a solution stabilizer, a complexing agent and an oxidation promoter.
The method of claim 6,
PH of the blackening treatment solution is 1.5 ~ 4.0 method for producing a black steel sheet excellent in blackening layer adhesion and surface appearance.
The method of claim 6,
The method of manufacturing a black steel sheet excellent in blackening layer adhesiveness and surface appearance comprising the step of further forming a resin layer on the blackening layer.
The method according to claim 14,
The method of manufacturing a black steel sheet excellent in blackening layer adhesiveness and surface appearance, further comprising the step of further forming an undercoat layer of organic, inorganic or organic / inorganic mixed system before forming the resin layer.

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