JP3389059B2 - Method for producing surface-treated steel sheet excellent in fingerprint resistance and grounding property - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a surface-treated steel sheet which is excellent in fingerprint resistance and earthing property, and is used in home electric appliances, particularly in electronic component equipment and the like requiring good earthing property. .

[0002]

2. Description of the Related Art Up to now, surface-treated steel sheets for home appliances have been required to have various product performances such as fingerprint resistance, corrosion resistance, and process galling property. For example, in the home electric appliance industry, it is possible to omit painting from the viewpoint of process saving and cost saving, excellent corrosion resistance that can be used naked,
There is a demand for a steel sheet having fingerprint resistance and work galling resistance. In order to satisfy these performances, various studies have been made and many products have been developed. Among them, a surface-treated metal plate has been developed in which a chromate treatment is applied to a plated metal plate and an organic composite film based on a special resin is formed on the plated metal plate, and currently, the most effective metal that satisfies the above performance is developed. It is mainly used as a board and a part for home appliances. For example, in Japanese Examined Patent Publication No. 14191/1992, an organic composite film is formed on a chromate-coated plated steel sheet in which a water-based organic resin is additionally adjusted with a colloidal sol having a specific fine particle size to form an organic composite film with improved corrosion resistance and fingerprint resistance. A method of manufacturing a surface-treated steel sheet having a coating is disclosed. Also,
Japanese Patent Application Laid-Open No. 5-65666 has also developed a paint in which a wax is added to an organic composite film for the purpose of improving the process galling property.

[0003]

In recent years, with the worldwide demand for electronic equipment parts, new characteristics are required for the surface-treated metal plate itself. The requirement is an electromagnetic wave shielding property which is indispensable for electronic component equipment and the like, and in order to satisfy this performance, the metal plate itself needs to have a good grounding property. A thin film of the organic composite film is an effective means for imparting good groundability to the organic composite film-coated metal plate that has been developed in the past. However, it is difficult to provide the grounding property while simply securing the respective properties originally possessed by the organic composite film-coated metal plate, such as fingerprint resistance, work galling property, and corrosion resistance, simply by reducing the thickness.

[0004]

In order to solve such a problem, the inventor has conducted earnest research and as a result, it has become possible to form a film in accordance with the surface roughness by controlling the non-volatile content of the paint. Furthermore, application of roll coater
By controlling the peripheral speed ratio of the target, it is possible to prevent uneven coating and to coat the thin organic composite film uniformly, and also to measure the center line average roughness of the chromate-coated steel sheet or the chromate-coated steel sheet. By controlling the coating amount of the coating and the coating, the coating area ratio of the coating is controlled, and the organic composite coating steel such as fingerprint resistance, corrosion resistance and work galling property is controlled.
We have found the findings that give good groundability while securing the various properties of the plate .

That is, the gist of the first invention is that the surface roughness is 1.0 μm or less in the center line average roughness Ra defined by JIS-B0601, and a chromate coating having an organic composite film as an upper layer. In the steel sheet or the chromate-coated plated steel sheet , after the organic composite coating is dried, the coating weight is 0.25 to 1 g / m ² , and the nonvolatile content is adjusted so that the coating area ratio of the organic composite coating on the steel sheet surface is 70 to 99%. A method for producing a surface-treated steel sheet having excellent fingerprint resistance and earthing characteristics, characterized by applying a coating material in an amount of 5 to 20% by weight. The gist of the second invention is to provide surface roughness. There is a 1.0μm or less in the center line average roughness Ra defined in JIS-B0601, in chromate coated steel sheet or chromate coated plated steel sheet having an organic composite coating on the upper layer The organic composite film after drying coating weight 0.25~1g / m ^2, and as coating area ratio of the organic composite coating to the steel sheet surface is 70% to 99%, Russia - Turkey - data - using a paint Excellent in fingerprint resistance and earthing property, which is characterized by applying an organic paint to a steel sheet with an applicator roll that rotates in the direction opposite to the traveling direction of the steel sheet at a peripheral speed 1.1 times faster than the line speed. It is a method of manufacturing a surface-treated steel sheet .

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION A thin organic composite film coating has various properties such as anti-fingerprint property, work galling property, corrosion resistance as well as earthing property.
Steel plates are greatly affected by the area coverage of the organic composite film on the steel plate . The higher the coverage area of the organic composite film, the better the fingerprints, work scuffing resistance, corrosion resistance and other properties that are guaranteed by having the organic composite film on the outermost surface, but on the other hand, the organic composite film that is an insulator. Hinders the energization, which deteriorates the earthing property. On the contrary, the smaller the covered area ratio of the organic composite film, the more the current-carrying points obtained in the uncovered part of the coating film and the better the grounding property, but the fingerprint resistance, work galling property, corrosion resistance and other performances deteriorate. . In order to provide the earthing property while ensuring the original performances of the organic composite film-coated plated steel sheet such as fingerprint resistance, work galling property, and corrosion resistance, the amount of the organic composite film deposited and the coverage area ratio should be within appropriate ranges. I have found that I need to control.

Further, the coating area ratio of the organic composite coating is greatly affected by the surface roughness of the chromate-coated plated steel sheet before coating. In particular, when a chromate-coated plated steel sheet with a rough surface before coating is used, the organic composite coating enters the recesses of the roughness when the coating is applied, so that the coating area ratio of the coating is significantly reduced. On the other hand, when a chromate-coated steel sheet with a low surface roughness is used, the coating area ratio of the coating film increases. In the case of thin film coating, the coating area ratio of the coating film is greatly affected by the non-volatile content of the applied coating material. As the non-volatile content of the coating material increases, the wet film thickness when the coating material is applied to the steel sheet becomes thinner, so that the coating material enters the concave portion having the roughness as shown in FIG.

Therefore, when the coating material is baked and dried, the coating material accumulates in the recesses as shown in FIG. 2, and the coating area ratio of the coating film is significantly reduced. A thick film coating that can completely cover the surface roughness will reduce the effect of the non-volatile content, but in the thin film area where the earthing property can be secured, the coating state of the coating will change significantly depending on the non-volatile content. . If the non-volatile content of the coating material is reduced, the wet film thickness when the coating material is applied to the steel sheet becomes thicker, so that the coating material can completely cover the surface roughness as shown in FIG. We also obtained the knowledge that a film can be formed according to the surface roughness.

Further, in the case of thin film coating, if the supply of the coating material to the steel sheet is insufficient in the coating film forming process, the coating film is rolled .
It was found that the ping-like unevenness was remarkably generated and the coverage of the organic composite film was significantly reduced. Based on these newly obtained findings, the amount of post-drying adhesion of the organic composite film, the coating area ratio of the coating film, the suitable range of the non-volatile content of the coating material, and the coating film forming conditions under which the looping pattern does not occur are determined. After examination, the first and second inventions were completed.

Next, the reasons for limiting each constituent element in the first and second inventions will be described. FIG. 5 schematically shows a cross section of the surface-treated steel sheet when there is plating in the first invention and the second invention. It is composed of a steel plate 1, a plating 2, a chromate 3 and an organic composite film 4 from the lower layer. Hereinafter, each film will be described. The steel plate targeted by the present invention is iron,
Includes iron-based alloys, copper, and copper-based alloys. The plated steel sheet contains a galvanized steel sheet and a zinc alloy-plated steel sheet , and is manufactured by any one of electroplating, hot dipping, vapor deposition plating, dispersion plating, and overlay plating. . Particularly, a zinc alloy-plated steel sheet has excellent performance in terms of work galling property and corrosion resistance. The plating amount is not particularly limited, but is preferably 5 g / m ² or more in consideration of corrosion resistance.

[0011] on the steel sheet, and after plating in the above conventional method the steel sheet, performing chromate treatment. Chromate adhesion amount does not need to be particularly limited, but is 5 mg in terms of Cr
/ M ² or less, it is difficult to obtain corrosion resistance, and it is 10 in terms of Cr.
When the amount is 0 mg / m ² or more, cohesive failure of the chromate itself occurs and the coating film adhesion cannot be obtained. Therefore, considering the corrosion resistance and the coating film adhesion, 5-100 mg / m ^{2 in} terms of Cr is preferable. Any of chromate treatment, electrolytic chromate, etching chromate, and coating chromate can be applied to the present invention. In particular, when importance is attached to the uniformity of appearance and adhesion of the top coating film, electrolytic chromate is optimal, and when importance is attached to corrosion resistance, application chromate is optimal. Steel plate or plated steel
Surface roughness of the chromate coated steel sheet or chromate coating plated steel sheet subjected to chromate treatment in a plate above the existing methods it is necessary to 1.0μm or less in the center line average roughness Ra defined in JIS-B0601 . Ra is 1.
When it is more than 0 μm, the coating area ratio of the coating film as a thin film is reduced, and sufficient fingerprint resistance may not be obtained.

The resin component in the organic composite film is not particularly limited, but is not limited to acrylic resin, olefin resin, acrylic olefin resin, urethane resin, epoxy resin, polyester resin, phenol resin, polycarbonate resin, polyolefin ionomer, and , And a mixture or copolymer of one or more of the melamine resins can be used. Acrylic resins are optimal when cost is important, epoxy and polyester resins are optimal when top coatability is important, and urethane resins are optimal when processability is important. The pigment is not particularly limited, but may be SiO ₂ , Cr ₂ O ₃ , Fe ₂ O ₃ , Fe.
₃ O ₄ , MgO, ZrO ₂ , SnO ₂ , Al ₂ O ₃ , S
One kind or a mixture of two or more kinds of b ₂ O ₅ can be used. Especially, SiO2 is economically optimal,
When it is contained in an amount of about 20% by weight, it is also advantageous in improving corrosion resistance and work galling property.

Next, the reason for limiting the non-volatile content of the coating material in the first invention will be described. The adjustment of the non-volatile components in this paint is important in the first invention, and if it is less than 5%,
When a paint is baked and dried, a phenomenon called "armpit" occurs, which may impair the appearance. Here, the waki is a phenomenon in which the coating film is cured before the volatile components are completely vaporized, and bubbles of the volatile components remain in the coating film after the film formation. Furthermore, when a solvent-based paint is used, a thinner is often used, which is disadvantageous in terms of cost. 20
When it is more than%, the coating area ratio of the coating film decreases, and sufficient fingerprint resistance, work galling resistance and corrosion resistance may not be obtained.
Therefore, it is necessary to adjust the non-volatile component of the paint to 5 to 20% by weight of the paint.

As the method for forming a coating film in the first invention, any method such as roll coating, spray coating, curtain flow coating, or a method of controlling the adhesion amount with an air knife after applying a coating liquid may be used. Next, a schematic view of a 2-roll coater used for coating in the second invention is shown in FIG. 6, and a schematic view of a 3-roll coater is shown in FIGS. 7 and 8. For coating the coating film, a two roll coater comprising a pickup roll 5 and an applicator roll 6 as shown in FIG. 6, a pickup roll 11 as shown in FIG. 7, and a transfer roll. 3 roll coater comprising a roll 12 and an applicator roll 13, a pickup roll 1 as shown in FIG.
4, applicator roll 15 and doctor roll 16
Any of the V type 3 roll coaters consisting of

The two roll coater coating shown in FIG.
The paint 9 filled in the printer pan 10 is picked up by the pick-up roll 5, transferred to the applicator roll rotating in the same direction, and further, the applicator roll.
The roll is a coating method in which the steel strip 8 is applied through a backup roll 7 rotating in the reverse direction, baked, and cooled. The 3-roll coater shown in FIG. 7 is a coating method in which a transfer roll that rotates in the same direction is added between the pickup roll and the applicator roll, which is mainly a high-quality coating. Effective when applying viscous paint.

The V-type 3-roll coater shown in FIG. 8 is a 2-roller.
This is a coating method in which a paint cutting doctor roll that rotates in the opposite direction to the pick-up roll of the ruler is installed, and it is effective to obtain a uniform appearance when a high-viscosity paint is used. The peripheral speed of the applicator roll is the line speed of the steel plate .
Which should be 1.1 times or more. If it is less than 1.1 times, the uniform supply of paint from the applicator roll to the steel sheet will be insufficient, and a loping pattern will occur, resulting in poor appearance, fingerprint resistance due to paint unevenness, and poor corrosion resistance. Occur.

In the first invention and the second invention, after forming the coating film,
If necessary, the coating film is dried and cured. The drying and curing conditions are appropriately selected depending on the type of paint. Drying and curing may be performed by a known method, for example, a hot air drying furnace, an induction heating furnace, a near infrared heating furnace, an electric furnace, a direct fire furnace, or the like. If the paint is a radiation curable paint, a radiation furnace may be used.
The coating amount is applied so that the dry coating amount is 0.25 to 1 g / m ² . When it is less than 0.25 g / m ² , the grounding property is good, but the fingerprint resistance, corrosion resistance, and process galling property are poor. When it is more than 1 g / m ² , fingerprint resistance, corrosion resistance, and process scuffing resistance are good, but groundability is poor.

The coating film coverage area ratio is CMA (Computer aided X) of a steel sheet coated with an organic composite coating.
-Ray Micro Analyzer, manufactured by JEOL Ltd.). CMA analysis conditions are: analysis diameter 2 μm, irradiation current 0.05 μA, irradiation time 30 mse
c, accelerating voltage of 15 kA, analysis of 250,000 points of 500 points vertically × 500 points horizontally (1 mm square), and the detection intensity of the element contained in the coating film at each analysis point is measured.
However, the measurement element for obtaining the coating film coverage is
Heavy elements with good sensitivity are desirable. The content rate of the measurement sample is the same as that of the measurement element, and the average coating adhesion amount is 1.25.
When the average strength of 250,000 points of a coated steel sheet having g / m ² is calculated, and a value of 1/10 thereof is used as a threshold value, and the number of points showing the detected strength higher than that is N, the coating film coating is performed. The area ratio (%) can be obtained from the following calculation formula. Coating film coating area ratio (%) = (N / 250,000) × 100 The coating film coating area ratio is preferably 70% or more. 70
When it is less than 0.1%, when the organic composite film-coated steel sheet is directly touched with a hand, fingerprint marks are conspicuous and impair the appearance, and further the corrosion resistance is deteriorated. On the contrary, in order to secure the earthing property, it is desirable that the coating film coverage area ratio is 99% or less. 99%
If it exceeds, the earthing property will be deteriorated and sufficient electromagnetic wave shielding property cannot be obtained.

[0019]

EXAMPLES Table 1 shows the constitutions of the organic composite film-coated steel sheets according to the first and second inventions. Steel sheet iron, plating using two types of stainless steel, as shown in Table 1, electro-galvanized (EG), 12% of the electrical Zn Ni content in wt%
-Ni alloy plating (ZL), hot dip galvanizing (GI)
Alloying hot-dip galvanizing (AS) having a Fe content of 10.5% by weight was applied to a predetermined amount and a predetermined steel plate shown in Table 1. The chromate treatment is an electrolytic chromate that is electrolytically treated using a commercially available sulfuric acid-based treatment liquid containing chromic acid, a reactive chromate that is obtained by etching nitric acid as a reducing agent in commercially available chromic acid, and a commercially available chromate. A coating chromate was used which was prepared by coating a treatment liquid in which silica was mixed in chromic acid at a weight ratio of 3 times and baking treatment was performed. 0.3μm center line average roughness Ra of the surface roughness of the chromate coated steel sheet or chromate coating plated steel sheet created is specified in JIS-B0601 in the manner described, 0.5 [mu] m,
Those having 0.8 μm, 1.0 μm and 1.2 μm were used.

[0020]

[Table 1]

As the coating film, a water-based paint shown in Tables 2 and 3 in which 20% by weight of silica sol is mixed with a commercially available acrylic resin, polyester resin, or epoxy resin is used, and a reaching plate after coating with a two-roll coater is used. It was baked at a temperature of 120 ° C. and water-cooled. Appearance, fingerprint resistance, earthing property, corrosion resistance, and work galling property were evaluated at each level, and the results are summarized in Tables 2 and 3.

The appearance was visually evaluated for the degree of occurrence of armpits and roping patterns. The following indicators were used for evaluation. No armpits or roping patterns are generated: ○ Some armpits or roping patterns are generated: △ Armpits or roping patterns are very noticeable: × ○ or △ is required for practical application.

The fingerprint resistance was evaluated by pressing an actual finger against each coated steel plate for 3 seconds and scoring the degree of conspicuousness of the fingerprint mark. The following indicators were used for rating. Fingerprint traces are completely unknown: Rating 5 Fingerprint traces are almost unknown: Rating 4 Fingerprint traces can be seen by good observation: Rating 3 Fingerprint traces are slightly noticeable: Rating 2 Fingerprint traces are highly noticeable: Rating 1 The fingerprint resistance requires a score of 3 or more for practical application.

The earthing property is JIS-C255 of each coated steel plate.
With the measurement method specified in 0, the interlayer resistance value (Ω · cm
² / sheet) was measured. For practical application, it is necessary to suppress the interlayer resistance value to 2.5 (Ω · cm ² / sheet) or less. The corrosion resistance was evaluated by measuring the area ratio of white rust and red rust generated 168 hours after the flat plate salt spray corrosion test, and evaluated according to the following criteria. No rust generation: ◎ Rust generation area ratio less than 5%: ○ Rust generation area ratio less than 20%: △ Rust generation area ratio 20% or more ： ×

The workability is L bending crank press 90
% Bending, pressing with a bending radius of 5 mm and no oil coating, the appearance was observed after the pressing and evaluated by observation. The evaluation was performed according to the following criteria. No flaws on the press section: ◎ Minor flaws on the press section: ○ Frequent flaws on the press section: △ Marked flaws on the press section: ×

[0026]

[Table 2]

[0027]

[Table 3]

The evaluation results will be described below. In Table 2,
No. 1-No. 14 and No. 20-No. No. 29 is the first invention example, and NO. Surface roughness of JIS 1-3 is JIS-B
The centerline average roughness Ra specified by 0601 is 0.8.
5 μm of chromate-coated electroplated steel sheet with non-volatile content,
0.5g / m2 of acrylic organic composite film containing 20% of silica sol using the coating composition changed to 10 and 20% by weight.
In the example of the present invention attached, the non-volatile content is 20%, which is slightly high N
O. No. 3 is No. 1, No. Compared with No. 2, the coating film coverage was low and the fingerprint resistance was slightly inferior, but it was sufficiently practical, and other performances were good. No. 1 has a nonvolatile content of 5
%, Which was slightly low, and some cracking was observed after baking, but it was within a practically applicable range. No. 2 is the appearance,
Good results were obtained in both fingerprint resistance and groundability.

NO. 4 to 6 has a surface roughness Ra of 0.8 μm
Acrylic organic composite film containing 20% silica sol is applied to the chromate-coated electroplated steel sheet of 0.3 as the coating amount.
Nos. 7 and 10 of the present invention were applied at a rate of 0.7 and 1.0 g / m 2.
No. 4 has a small amount of coating adhesion, so a roping pattern appears on the outside, but it has excellent grounding property, fingerprint resistance, corrosion resistance,
A good result was obtained in terms of processing galling property. No. 5, N
o. Since No. 6 has a high coating adhesion amount and a high coating film coverage, the groundability is slightly inferior, but the fingerprint resistance, corrosion resistance, and work galling property are good. NO. 7 to 12 are surface roughness Ra
In the example of the present invention in which the coating amount was changed by using a chromate-coated electroplated steel sheet whose thickness was changed to 0.3 μm, 0.5 μm, and 1.0 μm as the original plate, the coating amount was low if the coating amount was the same. When the roughening material was used for the original plate, the coating film coverage was high and the earth property was inferior, but the fingerprint resistance, corrosion resistance, and work galling were good. NO. The sample No. 11 had a surface roughness Ra of 1.0 μm and had a small coating adhesion amount, so that although the roping pattern was slightly generated, the groundability was good.

NO. 13, No. No. 14 is a chromate-coated electroplated steel sheet having a surface roughness Ra of 0.8 μm, in which the resin component in the organic composite film is changed to polyester resin or epoxy resin, and the coating adhesion amount is 0.5 g / m ² In each of the examples, regardless of the type of resin, the grounding property, fingerprint resistance, corrosion resistance, and processing galling property were good. In particular, NO. No. 14 was superior in workability and galling property. NO. 15, No. 16 has a surface roughness Ra of 0.
3 μm of non-volatile content on 8 μm chromate-coated electroplated steel sheet
0.5g / m of acrylic organic composite film containing 20% of silica sol by using coating material changed to 25% by weight
No. ^{2 in the} attached comparative example. Since the nonvolatile content of No. 15 was as low as 3% by weight, cracking occurred after baking, resulting in poor appearance. No. No. 16 has a high non-volatile content of 25% by weight, so that the coating film coverage is low and the groundability is good, but the fingerprint resistance and corrosion resistance are poor.

NO. 17, No. 18 is a comparison in which the coating adhesion amount of the acrylic organic composite coating containing 20% of silica sol on the chromate-coated electroplated steel sheet having a surface roughness Ra of 0.8 μm was changed to 0.2 g / m ² and 1.2 g / m ^2. As an example, NO. Since No. 18 has a low coating adhesion amount, a roping pattern is generated on the appearance, the coating film coverage is low, and the groundability is good, but the fingerprint resistance, corrosion resistance, and work galling property are poor. NO. Since No. 19 has a high coating adhesion amount, the coating film coverage is 100%, and the fingerprint resistance, the corrosion resistance, and the process galling property are good, but the groundability is poor. NO. Reference numeral 19 is a comparative example in which a chromate-coated electroplated steel sheet having a surface roughness Ra of 1.2 μm was used as the original plate and the coating adhesion amount was changed to 0.3 g / m ^2, and the coating area ratio of the coating film was low and the earth Good resistance, but poor in fingerprint resistance and corrosion resistance. NO. 20 ~
No. 29 is an example of the present invention in which the coating original plate was changed as shown in Table 1 and an acrylic organic composite coating containing 20% of silica sol was applied at a coating adhesion amount of 0.5 g / m ² ; It has excellent groundability. In particular, the ZL-plated steel plate and stainless steel used as the original plate showed excellent performance in corrosion resistance and work galling.

Next, in Table 3, No. 1-No. 1
5 and No. 21- No. 30 is a second invention example, N
o. Nos. 1 to 4 are acrylic-type organic composite coatings containing 20% of silica sol on a chromate-coated electroplated steel sheet having a surface roughness of 0.8 μm at the center line average roughness Ra specified by JIS-B0601. Rolling speed ratio 1.1,
In the example of the present invention in which 0.5 g / m ^{2 was} adhered under the conditions of 1.5, 2.0, and 2.5, the peripheral speed ratio was as small as 1.1. No. 1 had a roping pattern in its appearance, but was in a range that was sufficiently applicable to practical use. No. Nos. 2 to 4 showed good results in appearance, fingerprint resistance, and groundability.

No. 5 to 7 has a surface roughness Ra of 0.8 μm
An acrylic organic composite film containing 20% silica sol is applied to the chromate-coated electroplated steel sheet of 0.3 as a coating adhesion amount,
Examples of the present invention in which 0.7 and 1.0 g / m ^{2 were} adhered, No.
In No. 5, the amount of coating adhered was low, and thus a roping pattern was generated in the appearance, but the coating film coverage was low and the aerial property was good. No. 6, No. 7 has a large amount of paint,
Since the coating film coverage was also high, the groundability was slightly inferior, but the fingerprint resistance, corrosion resistance, and process galling resistance were good, and it was sufficiently applicable to practical use.

No. 8 to 13 has a surface roughness Ra of 0.3 μm.
m, 0.5 μm, 1.0 μm, the chromate-coated electroplated steel sheet was used as the original plate, and the coating amount was changed in the example of the present invention in which the coating amount and the peripheral speed ratio of the applicator roll were changed. If the amount of adhesion is the same, the lower the roughness of the original plate, the higher the coating area ratio and the slightly inferior ace property, but the fingerprint resistance, corrosion resistance, and work galling property are good. Yes (N
o. 3, No. 8, No. 10, No. 13 and No.
6, No. 9, No. (Compare 11). No. No. 12 has a surface roughness Ra of 1.0 μm and a small coating adhesion amount, so that a roping pattern is generated, but the ground is good.

No. 14, No. No. 15 was a chromium-coated electroplated steel sheet having a surface roughness Ra of 0.8 μm, in which the resin component in the organic composite film was changed to a polyester resin or an epoxy resin, and a coating adhesion amount of 0.5 g / m ² was applied. In the examples of the present invention, regardless of the type of resin, the groundability, fingerprint resistance, corrosion resistance, and work scuffing resistance were all very good. In particular, No. 1 using an epoxy resin. No. 15 was superior in workability and galling property. Nos. 16 to 20 are comparative examples in the second invention, and No. 16, No. No. 17 has a surface roughness of JIS-B0
Center line average roughness Ra prescribed by 601 is 0.8 μ
20% silica sol on m chromate-coated electroplated steel sheet
A peripheral speed ratio of 1.0 or less in a comparative example in which the contained acrylic organic composite film was adhered at 0.5 g / m ² under the conditions of an applicator roll peripheral speed ratio of 1.0 and 0.5. On the other hand, the roping pattern is conspicuous and the coating film coating area ratio is remarkably reduced.

No. 18, No. No. 19 is a chromium having a surface roughness Ra of 0.8 μm and the coating adhesion amount of an acrylic organic composite film containing 20% of silica sol on a coated electroplated steel sheet was changed to 0.2 g / m ² and 1.2 g / m ^2. In the comparative example, No. No. 18 had a low coating adhesion amount, so a loping pattern was generated on the appearance, and the coating film coverage ratio was low.
Although it has good scratch resistance, it is inferior in fingerprint resistance, corrosion resistance, and work galling resistance. No. Since No. 19 has a high coating adhesion amount, the coating film coverage is 100%, and the fingerprint resistance, corrosion resistance, and process galling property are good, but the ground property is poor.

No. Reference numeral 20 is a comparative example in which a chromium-coated electroplated steel sheet having a surface roughness Ra of 1.2 μm was used as an original plate and the coating adhesion amount was 0.3 g / m ² , and the coating area ratio of the coating film was low and -Although good in scratch resistance, it is inferior in fingerprint resistance and corrosion resistance. No. 21 to 30 are coating original plates in Table 1
In the second invention example of the present application in which an acrylic organic composite film containing 20% of silica sol was applied at a coating amount of 0.5 g / m ² as shown in FIG.
It has excellent durability. In particular, the ZL-plated steel plate and stainless steel used as the original plate showed excellent performance in corrosion resistance and work galling.

[0038]

As described above, the surface-treated metal sheet produced by the first and second inventions is excellent in fingerprint resistance and earthing property, and further has a corrosion resistance, a process galling resistance and the like. Since it has sufficiently satisfied the performance required for the plate, it can be applied to materials such as electronic component equipment which are required to have good fingerprint resistance and earthing property.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a cross section when a coating material containing a large amount of nonvolatile components is applied to a chromate-coated plated steel sheet ,

FIG. 2 is a schematic view of a cross section when a coating material containing a large amount of nonvolatile components is applied to a chromate-coated plated steel sheet and baked and dried;

FIG. 3 is a schematic diagram of a cross section when a coating material having a low nonvolatile content is applied to a chromate-coated plated steel sheet ,

FIG. 4 is a schematic diagram of a cross section when a coating material having a low non-volatile content is applied to a chromate-coated plated steel sheet and baked and dried;

FIG. 5 is a cross-sectional view of the film of the surface-treated steel sheet in the case where the plating of the first invention and the second invention is present,

FIG. 6 is a 2-roll coater used for coating of the second invention.
Schematic diagram of

FIG. 7: Three roll coater used for coating of the second invention
Schematic diagram of

FIG. 8 is a V-shaped three-roll roller used for coating of the second invention.
FIG.

[Explanation of symbols]

1 Steel Plate 2 Plating 3 Chromate 4 Organic Film 5 Pickup Roll 6 Applicator Roll 7 Backup Roll 8 Steel Strip 9 Coat Pan 10 Paint 11 Pickup Roll 12 Transfer Roll 13 Applicator roll 14 Pickup roll 15 Doctor roll 16 Applicator roll

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hidehito Goto 1 Kimitsu, Kimitsu-shi, Chiba Nippon Steel Co., Ltd. Inside the Kimitsu Works (72) Inventor Katsutoshi Enyama 1 Kimitsu, Kimitsu-shi, Chiba Made in Japan (56) References JP-A-8-224830 (JP, A) JP-A-3-94073 (JP, A) JP-A-4-157173 (JP, A) JP-A-9 -95786 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C23C 22/00-22/86 B05D 1/28 B05D 7/14

Claims (2)

(57) [Claims] 1. The surface roughness is 1.0 μm or less in terms of center line average roughness Ra defined by JIS-B0601.
In a chromate-coated steel sheet or a chromate-coated plated steel sheet having an organic composite coating on the upper layer, the weight of the coating after drying the organic composite coating is 0.25 to 1 g / m ² , and the coating area ratio of the organic composite coating material to the steel sheet surface is 70 to 99. %, A coating material having a nonvolatile content of 5 to 20% by weight is applied to the surface-treated steel sheet having excellent fingerprint resistance and grounding property. 2. The center line average roughness Ra defined by JIS-B0601 is 1.0 μm or less,
In a chromate-coated steel sheet or a chromate-coated plated steel sheet having an organic composite coating on the upper layer, the weight of the coating after drying the organic composite coating is 0.25 to 1 g / m ² , and the coating area ratio of the organic composite coating material to the steel sheet surface is 70 to 99. %, An organic paint is applied with a roll coater that rotates in the opposite direction to the traveling direction of the steel sheet at a peripheral speed 1.1 times faster than the coating line speed. Surface treatment with excellent anti-fingerprint and earthing characteristics, characterized by being applied to steel plate
Steel plate manufacturing method.