JP3188571B2 - Surface-treated metal plate excellent in processability, conductivity and corrosion resistance and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a field which is processed mainly by press molding and requires conductivity, that is, a processability used for home appliances, OA equipment, automobiles, etc.
The present invention relates to a surface-treated metal plate having excellent conductivity and corrosion resistance and a method for producing the same.

[0002]

2. Description of the Related Art In the manufacturing process of home appliances, OA equipment, automobile products, etc., steel sheets, Zn or Zn-based alloy-plated steel sheets, Al
Alternatively, various metal plates such as Al alloy plates are press-formed.

Conventionally, at the time of press working, a lubricating oil is applied to a metal plate in order to soften sliding resistance, and the working has the following problems. (1) Lubricating oil is often applied by spraying, and the lubricating oil is scattered around and the working environment is deteriorated. (2) After pressing, it is necessary to remove the lubricating oil,
In this degreasing step, a solvent (Freon, 1-1-1-trichloroethane, or the like) is used, or an alkali cleaning agent is used, so that measures to prevent pollution are required, resulting in an increase in cost and a poor working environment.

[0004] Under such a background, a technique that can omit the oiling and degreasing steps is disclosed in, for example, Japanese Patent Application Laid-Open No. 60-1985.
As disclosed in JP 103185 and JP-A-62-73938, a so-called lubricated steel sheet in which a chromate layer is formed on a galvanized steel sheet and a resin layer containing various lubricants is further formed thereon Has been developed.

However, the above prior art has a serious problem that the conductivity inherent in the metal plate is impaired because the resin layer for improving the press workability is uniformly formed on the metal plate. Was. That is, the resin is usually 10 ¹⁵ Ω
・ It has a very high volume resistivity around 1 cm,
Even when applied as a very thin film of about μm, it was present on the surface of the metal plate as a layer having an interlayer resistance of 10 ¹⁰ Ω or more, which impaired the conductivity and grounding properties of the product.

In order to improve the conductivity, Japanese Patent Application Laid-Open No. 63-83172 discloses a method for improving the conductivity by adding conductive particles to these resin layers. However, with this method, with the development of information equipment in recent years, the required level of conductivity and grounding of the metal surface has been increased, and it cannot be dealt with in terms of conductivity.

For example, a metal plate used for a computer chassis or the like needs to have an electromagnetic wave shielding property for preventing leakage of high-frequency electromagnetic waves, generation of noise due to electromagnetic induction, and the like. Therefore, the metal plate is required to have a surface electrical resistance of 1Ω or less. According to the above method, a large amount of conductive particles must be added in order to obtain sufficient conductivity for this required level, which complicates the resin coating operation and impairs the properties of the resin. There is a problem that so-called electrolytic corrosion (dissimilar metal contact corrosion) occurs due to the contact between the metal and the underlying metal, and the corrosion resistance is impaired.

Japanese Unexamined Patent Publication (Kokai) No. 63-114635 discloses a conductive surface-treated steel sheet having a discontinuous film in which an organic resin is dispersed on a chromate film. In the technology disclosed herein, it is difficult to coat fine particles at the time of coating because an electrostatic dispersion coating resin emulsion is used. Also, since a resin such as an acrylic emulsion is used, the particles are polymerized by polymerization of the resin after coating. There are problems such as an increase in diameter. That is, when the particle size of the lubricating particles is large, contact between the other metal and the metal plate coated with the lubricating particles is hindered, so that the grounding property is insufficient. Also,
If the particle size of the lubricating particles is large, the particles tend to fall off during handling, and as a result, the workability is reduced accordingly. In addition to this, no measures have been taken to improve the press workability of this steel sheet.

[0009]

SUMMARY OF THE INVENTION The present invention overcomes the above-mentioned problems of the prior art, and provides a surface-treated metal plate which can be press-formed without an oiling / degreasing step and has sufficient conductivity and grounding properties. It is an object of the present invention to provide a method of manufacturing the same.

[0010]

The present inventors have conducted intensive studies to overcome the disadvantages of the prior art, and as a result, the resin layer is not always essential for improving the workability, but a predetermined amount of the resin layer is required. It is sufficient if the lubricant particles can be fixed on the surface of the metal plate,
Further, the present inventors have found that the coverage of the surface of the metal plate with the lubricant layer must be less than 50% in order to secure the surface conductivity.

That is, according to the present invention, the adhesion amount of at least one side of a metal plate or a plated metal plate in terms of metal Cr is 5
Having a chromate layer of about 200 mg / m ² , and further, 5-10 organic lubricant particles having an average particle diameter of 30 μm or less.
A surface-treated metal plate having excellent workability, conductivity and corrosion resistance, comprising a second layer having an adhesion amount of 00 mg / m ² and a coating area ratio of the organic lubricating particles to the surface of the metal plate of less than 50%. Is provided.

Here, the organic lubricating particles are preferably made of one or more of paraffin wax, polyolefin wax, modified polyolefin wax, halogenated polyolefin wax and fluororesin.
Further, when the amount of the organic lubricant particles adhered is 10 mg / m ² or more,
It is preferably less than 100 mg / m ² , and the organic lubricating particles preferably have an average particle size of 20 μm or less. Preferably, the surface of the organic lubricating particles is modified or oxidized with maleic acid. Further, it is preferable that the chromate layer contains silica in a weight ratio of SiO ₂ / Cr in a range of 0.1 to 6.0.

[0013] The present invention also relates to the present invention, wherein at least one surface of a metal plate or a plated metal plate has an adhesion amount of 5 to 20 in terms of Cr.
A chromate layer having a concentration of 0 mg / m ² is formed, and a dispersion or emulsion containing the organic lubricating particles in a concentration of 0.1 to 40 wt% is further formed thereon to a wet film thickness of 0.2 to 10 μm. A surface treated metal sheet having excellent workability, conductivity and corrosion resistance, wherein a second layer having a coating area ratio of the organic lubricating particles on the surface of the metal sheet of less than 50% is formed by coating on the surface of the metal sheet. It provides a method. Here, the method of applying the organic lubricating particles to at least one surface of the metal plate or the plated metal plate is preferably a roll coater, a spin coater or a dip ringer.

[0014]

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

The metal plate or plated metal plate in the present invention means a steel plate, a zinc or galvanized steel plate, an aluminum or aluminum alloy plated steel plate, an aluminum or aluminum alloy plate, or the like for use in home appliances, OA equipment, automobiles and the like. Widely encompasses a metal plate processed by the method described above.

The chromate layer formed as the first layer on the surface of the metal plate or the plated metal plate in the present invention is intended to be used indoors or to prevent corrosion in a relatively mild corrosive environment which is not directly exposed to wind and rain. . This chromate layer can be arbitrarily selected from reactive chromate, electrolytic chromate, and coating chromate depending on the production line of a base metal and a surface treatment company. Also, C
If the amount of r deposited is less than 5 mg / m ^{2 in} terms of metallic Cr, the anticorrosion effect is not sufficient, and if it exceeds 200 mg / m ² , the anticorrosion effect is saturated and is not economical. There is a risk of peeling off the coating film, so the chromate adhesion amount is 5 to 200 mg / m
Limited to the range of ² .

In the present invention, as shown in FIG. 1, a first chromate layer 2 is formed on a metal plate 1, and a second layer of organic lubricating particles 3 is further provided thereon. Here, the organic lubricating particles 3 are made of an organic material, and are particles having a lubricating effect during press working or the like, and are present as particles dispersed when attached to the metal plate surface. As the organic lubricating particle layer, any of synthetic wax and natural wax may be used, but from the viewpoint of workability of the surface-treated metal plate of the present invention, paraffin wax, polyolefin wax,
It is preferable to select organic lubricating particles comprising one or more of modified polyolefin wax, halogenated polyolefin wax, and fluororesin.

Adhesion amount of organic lubricant particles for forming second layer
Is 5mg / m^TwoIf less than 10, the lubricating effect is not sufficient and
00mg / m^TwoIf it exceeds 50, the conductivity is reduced.
000mg / m^TwoLimited to the range. The organic lubricating particles
Adhesion amount is less than 0.1Ω surface electric resistance of surface treated metal plate
In order to obtain better processability, 10 mg / m ^Two
100 mg / m^TwoMore preferably in the range of
New

Further, as shown in FIG. 2, if the organic lubricating particles cover the metal plate surface at an area ratio of more than 50%, sufficient conductivity cannot be obtained, so that the area ratio is limited to less than 50%. In addition, the measurement of the coating area ratio can be performed according to a microscope test method (JIS G 0555) for nonmetallic inclusions of steel.

The average particle size of these organic lubricating particles is 3
If it exceeds 0 μm, it will easily fall off during handling before press working. In addition, metal contact between the surface-treated metal plate and another metal is hindered, and the grounding property is impaired. For this reason,
In order to maintain good workability and grounding properties, the average particle size of the organic lubricating particles is 30 μm or less, more preferably 2 μm or less.
The thickness is preferably 0 μm or less.

Further, by modifying or oxidizing the surface of the organic lubricating particles with maleic acid, the adhesion to the metal and the coating film applied to the upper layer is increased. This is due to a chemical bond between a terminal functional group and a metal atom generated by modifying or oxidizing the surface of the organic lubricating particles with maleic acid.

In order to obtain an even higher degree of conductivity (earth property), it is more preferable that the chromate layer contains silica. This is because the addition of silica to the chromate layer can reduce the coverage of the organic lubricating particles while ensuring corrosion resistance. Since the coverage of the organic lubricating particles is less than 50%, the corrosion resistance performance mainly depends on the chromate. In an environment where high corrosion resistance is required, the silica in the chromate is contained in a SiO ₂ / Cr weight ratio of 0.1 to 0.1%.
Although it can be contained in the range of 6.0, the addition of silica is inferior in corrosion resistance when the weight ratio of SiO ₂ / Cr is less than 0.1, while the weight ratio of SiO ₂ / Cr exceeds 6.0. Therefore, the weight ratio of SiO ₂ / Cr is set in the range of 0.1 to 6.0.

The surface treatment of the metal plate is performed on at least one surface of the metal plate. When the surface of the metal plate on the punch side is constrained by the punch as in a simple press working and the slidability of only the surface of the metal plate on the die side is a problem, processing on only one side is sufficient. On the other hand, when high slidability is required for both surfaces, the surface treatment of the present invention may be applied to both surfaces.

Next, as a method of manufacturing the surface-treated metal sheet of the present invention, a chromate layer having an adhesion amount of 5 to 200 mg / m ² in terms of Cr is formed on at least one surface of the metal sheet or plated metal sheet. Further, a dispersion or emulsion containing a concentration of the organic lubricating particles in the range of 0.1 to 40 wt% is applied thereon so as to have a wet film thickness of 0.2 to 10 μm, so that the organic lubricating particles with respect to the surface of the metal plate are coated. A second layer having a coverage area ratio of less than 50% is formed.

The reason why the concentration of the organic lubricating particles in the dispersion or emulsion is limited to the range of 0.1 to 40% by weight is that when the concentration is less than 0.1% by weight, a wet film for obtaining a predetermined adhesion amount is obtained. The thickness (the thickness immediately after the application of the dispersion or emulsion containing the organic lubricating particles) is too large, making it difficult to control the uniform wet thickness.
If the content is more than wt%, the viscosity of the liquid becomes too large and the wet film thickness tends to be non-uniform.

The reason why the wet film thickness of the dispersion or emulsion is limited to 0.2 to 10 μm is that when the wet film thickness is less than 0.2 μm, the coating roll is easily damaged by contact with a metal plate, This is because the layer is peeled off, the corrosion resistance is reduced, and if it exceeds 10 μm, it is difficult to control the uniform wet film thickness.

As a method of applying the organic lubricating particles 3 on the chromate layer 2, any method of a roll coater, a spin coater or a dip ringer may be used.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to embodiments.

(Examples) The following steel sheets, plated steel sheets, and aluminum alloy sheets were used as test pieces (A to D, respectively).
Steel plate material is JIS standard JIS G3141 SPCC
It is an equivalent. ). A: Cold-rolled steel sheet, 1 mm thick B: Electro-galvanized steel sheet, 1 mm thick, galvanized coating weight 20 g / m ² C: Electro-zinc-nickel plated steel sheet, 1 mm thick Zinc-nickel coated weight, 20 g / m ² , containing nickel Ratio 12% D: 5% Aluminum-zinc hot-dip coated steel sheet Thickness 1
mm, coating weight 60 g / m ² D ': 55% aluminum-zinc hot-dip coated steel sheet 1 mm thick, coating weight 60 g / m ² E: JIS A5182 aluminum alloy sheet 1 m thickness
m After the above metal plate was degreased with steam by using 1-1-1-trichloroethane, chromate was applied by a spin coater, and dried.
I baked it. Thereafter, a liquid in which various waxes shown in Table 1 were dispersed in water or a solvent was applied by a spin coater and dried (120 ° C.) to prepare a test piece.

The chromate adhesion amount was determined by X-ray fluorescence analysis.
The elements were quantified, and the amount of wax attached was determined by quantifying the C element by X-ray fluorescence analysis. The coverage of the metal plate surface with the wax was determined by observing the surface with a SEM (× 100
0) was obtained as an average value of arbitrary 20 visual fields.

The workability was evaluated by the limit drawing ratio in a cylindrical drawing test (without oil coating) with a punch diameter of 33 mmφ. (1) Steel sheet and plated steel sheet ：: Drawing ratio LDR 2.30 or more, ２: 2.24 or more and less than 2.30, Δ: 2.12 or more and less than 2.24, ×: LDR less than 2.12. (2) Aluminum alloy plate ◎: LDR 2.12 or more, ：: LDR 1.96 or more and less than 2.12, Δ: LDR 1.90 or more and less than 1.96, ×: LDR less than 1.90.

The conductivity was evaluated by measuring the surface resistance value with a Mitsubishi Yuka surface resistance meter Loresta MCP-tester (trade name). The measurement was performed 10 times and evaluated by the average value. ◎: less than 0.1Ω, ○: 0.1 or more and less than 0.5Ω, Δ: 0.5 or more and less than 2Ω, ×: 2Ω or more.

The corrosion resistance was maintained in a thermo-hygrostat at 50 ° C. and a relative humidity of 98% or more for 100 hours, and evaluated as follows. ：: No discoloration or spot rust was generated. X: Discoloration or spot rust was generated. Further, the corrosion resistance was evaluated by a JIS2371 salt spray test.

The following five types of waxes and the following two types of chromates were used in this example, but it goes without saying that the present invention is not particularly limited only to these agents.

Wax Sannopco SN wax 22DS-F polyethylene wax Sannopco SL 506 carnauba wax Sannopco SL 630 halogenated polyolefin wax Nippon Oil Co., Ltd. Paranoc 203 paraffinic wax Sanyo Chemical Co., Ltd. Permarine KUE-150 polyethylene oxide wax

Chromate 4513H (silica-free) manufactured by Nippon Parkerizing Co., Ltd. Cosma-150 (SiO ₂ / C manufactured by Kansai Paint Co., Ltd.)
r = 2.0)

Table 1 summarizes the surface treatment conditions and the evaluation test results. As is evident from the results, the materials of the present invention all show excellent workability, conductivity and corrosion resistance, whereas Comparative Examples C-1, E-1, N-1, and G-1 have been subjected to a surface treatment. Since it is not performed, it is inferior in workability and corrosion resistance. Comparative Example C-
2, E-2, N-2, and G-2 were inferior in corrosion resistance due to insufficient chromate adhesion amount, and C-3, E-3, N-3, G-3,
A-1 and A-2 have poor workability due to insufficient wax. C
-4, E-4, N-4, G-4 and A-3 are inferior in conductivity due to excess wax. C-5, E-5, N-5, G-
5, A-4 has an excessively large particle diameter of the wax and is inferior in workability.

[0038]

[Table 1]

[0039]

[Table 2]

[0040]

[Table 3]

[0041]

[Table 4]

[0042]

[Table 5]

[0043]

As described above, according to the present invention,
It is possible to remarkably improve workability without deteriorating the conductivity (surface resistance) of steel plates, plated steel plates, aluminum plates, etc., and to form metal plates that can be press-formed without oiling and degreasing steps and have good conductivity. Can be provided. As a result, the present invention can be applied to a member requiring a high grounding property, which is difficult with a conventional lubricating coating material, and the pressing factory process can be omitted and the environment can be further improved.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a surface-treated metal plate of the present invention.

FIG. 2 is a graph showing a relationship between a coating area ratio (%) and a surface electric resistance (Ω) in the surface-treated metal plate of the present invention.

[Explanation of symbols]

 1 metal plate 2 chromate layer 3 organic lubricating particles

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI C10M 107/38 C10M 107/38 C23C 22/00 C23C 22/00 Z (72) Inventor Yoshihiro Naruse Chuo-ku, Chiba-shi, Chiba No. 1, Kawasaki-cho, Kawasaki Steel Works, Ltd. (56) References JP-A-5-65667 (JP, A) JP-A-5-311454 (JP, A) JP-A-4-313368 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) C23C 22/00-22/86 B05D 5/08 B05D 7/14 B32B 15/08 C10M 107/02 C10M 107/38

Claims (8)

(57) [Claims] 1. A metal plate or a plated metal plate having on at least one side thereof a chromate layer having an adhesion amount of 5 to 200 mg / m ² in terms of metal Cr, and further having an average particle size of 30 μm.
m of the organic lubricating particles having an adhesion amount of 5 to 1000 mg / m ² and the covering area ratio of the organic lubricating particles to the metal plate surface is 5
A surface-treated metal sheet having excellent workability, conductivity and corrosion resistance, comprising a second layer that is less than 0%. 2. The organic lubricating particles are paraffin wax,
2. The surface-treated metal sheet according to claim 1, comprising one or more of polyolefin wax, modified polyolefin wax, halogenated polyolefin wax, and fluororesin. 3. The surface-treated metal sheet having excellent workability, conductivity and corrosion resistance according to claim 1, wherein the amount of the organic lubricating particles adhered is 10 mg / m ² or more and less than 100 mg / m ² . 4. The surface-treated metal sheet according to claim 1, wherein the organic lubricating particles have an average particle size of 20 μm or less. 5. The surface-treated metal sheet according to claim 1, wherein the surface of the organic lubricating particles is modified or oxidized with maleic acid. 6. The silica in the chromate layer is SiO ₂ /
The surface-treated metal sheet having excellent workability, conductivity and corrosion resistance according to any one of claims 1 to 5, which contains Cr in a weight ratio of 0.1 to 6.0. 7. A chromate layer having an adhesion amount of 5 to 200 mg / m ² in terms of Cr is formed on at least one surface of a metal plate or a plated metal plate, and the concentration of the organic lubricating particles is further reduced to 0.1 to 200 mg / m ^2. The second layer in which the coating area ratio of the organic lubricating particles to the surface of the metal plate is less than 50% by applying a dispersion or an emulsion containing 40 wt% in a range of 0.2 to 10 μm. A method for producing a surface-treated metal sheet having excellent workability, conductivity and corrosion resistance, characterized by forming a surface. 8. The method according to claim 7, wherein the method for applying the organic lubricating particles to at least one surface of the metal plate or the plated metal plate is a roll coater, a spin coater or a dip ringer. A method for producing a surface-treated metal plate.