JP3082864B2 - Electrodeposition coating member and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodeposition coating member, and more particularly to an electrodeposition film having a shielding property for forming a housing used for optical equipment such as a camera, home electric appliances, OA equipment, office equipment or measuring equipment. And to a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, electronic circuits have become smaller, more complicated and more precise, and malfunctions and noise due to electromagnetic waves generated from other components and circuits have become important problems. In addition, the electronic circuit itself also generates an electromagnetic wave and its influence on the surroundings is also an important problem, and in order to prevent such a problem, it is required to shield the penetration and radiation of the electromagnetic wave into the electronic circuit.

[0003] As a method of shielding electromagnetic waves, there is conventionally known a method of surrounding a circuit board with a metal casing made of a conductive material. However, housings made of plastic materials have recently become mainstream as products become smaller and lighter. As a method for making the plastic casing conductive, spray coating with a conductive paint is the mainstream, and other methods include zinc spraying, electroless plating, vacuum deposition, and use of a conductive plastic.

[0004] However, the conventional method has the following disadvantages. Since the conductive paint for spraying has a conductive filler content of 60% by weight or more and a coating thickness of 30 μm or more for a copper filler and 50 μm or more for a nickel filler, there is no electromagnetic shielding effect. However, this is not preferable as a decorative coating for the exterior of the housing.

When metal powder is used as a filler,
Due to the large specific gravity of the metal powder, it is necessary to redisperse when using the paint, but this is not easy. To solve these,
For example, JP-A-59-223763 discloses a conductive paint for electromagnetic shielding using a mica powder coated with nickel as a conductive filler. However, even with this coating material, a sufficient electromagnetic shielding effect cannot be obtained unless the coating film is formed thicker than 50 μm. Further, in a case having a complicated shape, the coating film thickness tends to be non-uniform, and as a result, the shielding effect may be insufficient.

[0006] Next, in order to ensure shielding properties, zinc spraying needs to have a thick film thickness of 50 to 100 µm, and further has difficulty in adhesion to a substrate, and requires a step such as blasting. Become. In addition, there is a problem in mass productivity such as deterioration of working environment due to the zinc vapor gas.

[0007] Regarding electroless plating, for example, when copper plating is formed to a thickness of 1.0 to 1.5 µm or more,
Although it has an electromagnetic shielding effect, plating is applied to the entire housing, so when using the product as a housing, a coating film is formed on the plating surface to improve the appearance and enhance commercial value. It becomes essential. However, in this case, there is a problem that poor adhesion between the plated surface and the painted surface occurs.

In particular, when only copper plating is applied, corrosion occurs due to aging and the performance is deteriorated. Therefore, it is necessary to apply nickel plating to this surface to prevent deterioration in quality. Further, since this nickel plating greatly impairs the adhesion to the coating film, it is necessary to apply a very limited coating such as a special coating, for example, Origin Plate Z (trade name, manufactured by Origin Electric Co., Ltd.). In addition, it has a significant effect on cost and has no mass productivity.

On the other hand, there is known a conductive plastic housing formed by mixing a resin with a conductive filler such as a metal powder or a metal fiber having a particle size of several tens μm or more. However, this plastic housing has a remarkable unevenness on the surface, and cannot be used as an exterior when it is in a molded state, so that there is a problem that a cosmetic coating must be applied in order to obtain commercial value. In addition, because of poor conductivity, secondary processing is required for complete electromagnetic wave shielding, which is not mass-produced. In addition, the conductive plastic material itself is expensive, which also has practical limitations.

[0010] Further, as for the exterior coating of the housing, there is a strong desire for a high quality external appearance, and there is a high need for a satin-like external appearance. For this reason, exterior coating is currently performed after blast processing etc. is performed before painting, but when coating on a case with a step or vertex angle, the flat part and the step or vertex A difference occurs in the film thickness of the film, defects such as invisibility occur, and a high-quality satin-like appearance cannot be obtained.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the prior art, and is a member for forming a housing, particularly a stepped ridge or a top of a housing. An object of the present invention is to provide an electrodeposition coating member in which a corner portion and a flat portion are externally and uniformly coated with almost no difference in the thickness of a coating film, and a method for manufacturing the same. Another object of the present invention is to provide an electrodeposition coating member having a high-quality satin-like appearance and having excellent electromagnetic wave shielding properties, and a method of manufacturing the same.

[0012]

That is, an electrodeposition coating member of the present invention is a casing having a step or a vertex or both on the surface, and at least a ridge or a vertex of the step of the casing. Or both are metallized ceramic powder and metallized
Naturally, do not contain at least one selected from mica powder.
And coated with an electrodeposition coating film containing conductive particles.

[0013] The method for producing an electrodeposition coated member of the present invention comprises:
A method for producing an electrodeposition coated member in which at least a ridge portion or an apex portion or both of the steps of a housing having a step or an apex angle or both on the surface is coated with an electrodeposition coating film containing conductive particles. Metallized ceramic powder and gold
One or two kinds of powders selected from genus mica powder
The casing is immersed in an electrodeposition coating material containing conductive particles to perform electrodeposition, and the surface roughness has a center line average roughness (Ra) of 0.3 to 5 μm. In addition, an electrodeposition coating film having an electromagnetic wave shielding property is formed on the surface of the housing.

That is, as a result of various studies on the electrodeposition film containing conductive particles, the present inventors have found that the particle size of the conductive particles in the electrodeposition paint and the electrodeposition coating member with respect to the applied voltage at the time of electrodeposition. The present invention is based on the finding of the relationship with the surface roughness of the surface.

Hereinafter, the present invention will be described in detail. The electrodeposition coating member of the present invention is a member for forming a housing having a step or a vertex on the surface, and the electrodeposition coating member having a flat portion and a ridge portion or a vertex of the step containing conductive particles. By coating with a coating film, the exterior is evenly coated with almost no difference in the thickness of the coating film between the stepped ridge or vertex and the flat portion of the housing.

FIG. 1 is a partial sectional view showing an example of the configuration of the electrodeposition coating member of the present invention. The electrodeposition coating member of the present invention is a member forming a casing having a step or a vertex on the surface, and at least a ridge portion or a vertex of the step is formed as shown in FIG.
As shown in FIG. 1, a metal thin film 2 such as a metal copper thin film is formed on a non-metallic member 1, and conductive particles are formed on a chemically colored film 3 of an underlayer 5 having a chemically colored film 3 provided thereon. It has a configuration in which the electrodeposition coating film 4 to be contained is provided and exterior coating is performed.

FIG. 2 is a partial explanatory view showing an example of a housing using the electrodeposition coating member of the present invention. As shown in the figure, a flat portion 8, a ridge portion 6 and a vertex portion 7 of a step are exteriorly coated with an electrodeposition coating film containing conductive particles (hereinafter referred to as an ED film). The thickness of the coating film at the ridge line portion 6 or the apex angle portion 7 of the step and the flat portion 8 is substantially uniform with little difference in thickness.

In the present invention, as the chemical colored film 3, for example, a chemically colored film obtained by subjecting a metal thin film 2 formed on a substrate to a surface treatment is an electrodeposition coating film formed thereon. This is preferred because of good adhesion to the polymer. It is not clear why this chemically colored film shows good adhesion to the electrodeposition film, but the chemically colored film has very fine holes (po).
ur), a physical adsorption occurs between the ED film and the chemical adsorption between the functional groups of the polymer in the ED film and the active sites on the surface of the conductive particles and the chemical coloring film. Therefore, it is considered that extremely excellent adhesion occurs.

Further, in the present invention, a chemically colored film obtained by surface treatment of copper, for example, copper oxide, cuprous oxide,
Copper carbonate, copper sulfide, copper ammonium hydroxide and the like have excellent adhesion of the ED film, and copper oxide is particularly suitable in terms of the adhesion of the ED film to the substrate, the corrosion resistance of the metal thin film 2, and the uniformity of the ED film. Used for Therefore, in the present invention, it is preferable to use copper as the metal thin film 2, and when a material other than copper is used as the metal substrate, it is preferable to apply copper plating around the material.

At this time, the metal thin film 2 is for forming a chemically colored film on an electrode and a surface for forming an ED film, and has a film thickness of 0.05 to 0.2 μm, especially 0.1 μm. 1 to 0.15 μm is preferred. When the film thickness exceeds 0.2 μm, it takes a long time to form the metal thin film, and the work efficiency decreases with an increase in the weight of the electrodeposition coating member, which is not preferable.

As a method of forming the above-mentioned chemically colored film, for example, a mixed solution of copper sulfate + potassium chlorate, copper chloride +
A copper oxide layer can be formed by immersing the substrate on which the copper plating layer is formed in a mixed solution of copper acetate and alum.
As a method of forming a copper sulfide layer, potassium sulfide +
A method of dipping in a mixed solution of ammonium chloride, a mixed solution of sodium hyposulfite and lead acetate, or the like can be given. As a method of forming a copper hydroxide layer, a method of dipping in a mixed solution of copper nitrate + ammonium chloride + acetic acid or the like can be mentioned. In addition, as a method for forming a copper suboxide layer which is one of the oxide layers, a method of immersing in a mixed solution of copper sulfate and sodium chloride, a mixed solution of copper sulfate and ammonium chloride, or the like is given.

Next, the conductive electrodeposition coating film 4 of the present invention comprises:
The conductive particles are co-deposited with a resin capable of being electrodeposited on the chemically colored film at a high density. Even if it is a thin film, it has conductivity and functions as a coating film for electromagnetic shielding.

In the present invention, the conductive particles to be codeposited on the electrodeposited film are not particularly limited as long as they can impart conductivity to the electrodeposited film. Metal plated powder (metallized ceramic powder)
Powder (metallized natural mica), metal powder on the surface of natural mica powder, ultrafine metal powder having an average particle diameter of 0.01 to 5 μm, resin powder having a metal coating on the surface, or a mixture thereof Can be used.

In particular, when the metallized ceramic powder and the metallized natural mica among the above-mentioned conductive particles are co-deposited, a heating treatment is performed after the completion of the electrodeposition to cure the electrodeposited film. As for the temperature, a temperature of 130 to 180 ° C. is required to be completely cured at a low temperature of 90 to 100 ° C., and the adhesion to the substrate can be further strengthened. Particularly preferred when applied as a coating.

It is not clear why electrodeposited films containing these metallized ceramic powders or metallized natural mica powders or mixtures thereof have excellent adhesion and cure at low temperatures. Unlike ceramic particles and metalized natural mica powder, whose surface is oxidized quickly, the interaction between the powder surface and the metal coating maintains the active points on the powder surface to some extent stable Therefore, it is considered that the active powder surface becomes a cross-linking point at the time of curing to accelerate the curing of the electrodeposited film, and that more chemical bonds with the chemically colored layer can be formed.

As the metallized ceramic powder and the metallized natural mica powder used in the present invention, the surface of the ceramic powder or the natural mica powder is Cu, Ni, Ag, A
Those plated with u, Sn or the like are used. The plating on the surface of these powders requires Cu,
Ag and Ni can be suitably used, and electroless plating is suitable as a forming method on the powder surface.

The plating thickness on the surface of the powder is 0.1 mm.
When the thickness is 0.05 to 3 μm, particularly 0.15 to 2 μm, excellent shielding properties and good coating film properties at the time of low-temperature curing can be provided. When the plating is formed thicker than 3 μm, the surface characteristics are similar to metal particles. As a result, the surface is extremely active, and active sites that are oxidized in the air and contribute to cross-linking are reduced, so that the electrodeposited film tends to be insufficiently cured during low-temperature baking.

In the formation of Ni plating on the powder,
For example, as disclosed in Japanese Patent Application Laid-Open No. 61-2767979, an aqueous suspension of powder is prepared, and then an electroless nickel plating aging solution is added to this suspension to form a nickel plating on the powder surface. When Ni plating is performed with a low phosphorus content, for example, 5% or less, the conductivity is improved, and an electrodeposition film having shielding properties almost equivalent to Cu plating powder can be formed.

The average particle size of the ceramic powder and the natural mica powder is from 0.1 to 5 μm, especially from 0.3 to 5 μm, in consideration of the surface area contributing to the surface activity and the dispersibility in the electrodeposition paint. 3 μm, more preferably in the range of 0.5 to 2 μm.

The ceramic used in the present invention includes, for example, aluminum oxide, titanium nitride, manganese nitride, tungsten nitride, tungsten carbide, lanthanum nitride, aluminum silicate, molybdenum disulfide,
Examples include titanium oxide and silicic acid, and examples of natural mica include phlogovite mica, sericite mica, and muscobite mica.

Next, as the conductive particles, as described above, an ultrafine metal powder having an average particle size of 0.01 to 5 μm or a resin powder having a surface metalized with an average particle size of 0.1 to 5 μm, as described above. Can also be used. For example, as the ultrafine metal powder, Ag, Co, Cu, F obtained by a thermal plasma evaporation method can be used.
e, Mn, Ni, Pd, Sn, Te and the like, and the average particle size thereof is 0.01 to 5 μm, particularly 0.01 to 5 μm.
The thickness is preferably 0.1 μm, more preferably 0.03 to 0.07 μm. If it is less than 0.01 μm, a secondary coagulation effect occurs, and if it exceeds 5 μm, it precipitates in the electrodeposition paint, and the coating member gives a metallic luster and hinders painting of a desired color.

The metallized resin powder of the present invention includes
For example, fluorine resin, polyethylene resin, acrylic resin,
On the surface of a resin powder such as polystyrene resin or nylon, Cu or Ni is coated in a thickness of 0.05 to 3 μm as in the case of ceramic.
m. The average particle size of the resin powder is preferably about 0.1 to 5 μm.

When the above-mentioned conductive particles are individually contained in an electrodeposition film, an electrodeposition coating member having electromagnetic wave shielding properties and good coating physical properties can be obtained. When the ultrafine metal powder, the metallized resin powder or the mixture thereof is added to the mica powder or the mixture 1 at a weight ratio of 0.2 to 3 as shown in FIG. Of the metallized ceramic powder and / or the metallized natural mica powder 31
Alternatively, the metallized resin powder 32 fills and the contact area between the powders increases, so that the shielding property is further improved, and the heat treatment at a low temperature is performed by the action of the metallized ceramic powder and / or the metallized natural mica powder. An electrodeposition coating member having excellent coating film properties and good adhesion to a substrate can be obtained.

In the present invention, the electrodepositable resin includes:
Conventionally, resins used for electrodeposition coatings can be used.For example, in the case of anion-type electrodeposition coatings, anionic functional groups such as carboxyl groups for imparting a negative charge and hydrophilicity necessary for electrodeposition of the resin. Resin, specifically, an acrylic / melamine resin, an acrylic resin, an alkyd resin, a maleated polybutadiene, a half ester and a half amide thereof, into which an anionic functional group is introduced.

In the case of a cationic electrodeposition paint, a resin having a cationic functional group such as an amino group in order to impart a positive charge and hydrophilicity, specifically, an epoxy resin having a cationic functional group introduced therein , Urethane resin, polyester resin, polyether resin and the like. Also, among these resins, those that are not self-crosslinkable are, as curing agents,
For example, it is used together with a mixture with a melamine resin or a blocked polyisocyanate compound.

As the content (eutectoid content) of the conductive particles in the electrodeposition coating film of the present invention, the amount of attenuation in electromagnetic shielding properties satisfies, for example, 70 dB or more, and the base material as a decorative coating film In consideration of the adhesiveness to the film and the flexibility of the film, the cured electrodeposited film has a content of 5 to 50% by weight, especially 10 to 50% by weight.
30% by weight, more preferably 15 to 25% by weight. 50
If the amount exceeds 5% by weight, the coating film becomes brittle and is unsuitable as an exterior coating film. If the amount is less than 5% by weight, sufficient shielding properties cannot be obtained.

The conductive particles can be identified by an X-ray microanalyzer, and the amount of eutectoid can be measured by analyzing by thermogravimetric analysis.

As described above, according to the present invention, the conductive particles are dispersed in the electrodeposition resin and are co-deposited in the electrodeposition coating film by the electrophoretic action, whereby the ridge or the apex of the step of the housing is obtained. There is almost no difference in the thickness of the coating film between the portion and the flat portion, the coating is uniformly applied, and the casing can be provided with electromagnetic wave shielding properties by the outer coating film. Furthermore, when metallized ceramic powder or metallized natural mica is contained as the conductive particles, the curing reaction is sufficiently performed in spite of the heat treatment at a low temperature (100 ° C.) even in the physical properties of the coating film, The same or higher physical properties as the high-temperature cured film can be obtained.

The surface roughness of the electrodeposition coating film is 0.3 to 5 μm in center line average roughness (Ra), preferably 0.1 to 0.5 μm.
It is preferably from 5 to 4.0 μm, more preferably from 0.7 to 3.0 μm. If it is less than 0.3 μm, there is a problem in the cosmetic properties,
That is, it is difficult to obtain a satin-like appearance, and if it exceeds 5 μm, the commercial value on the exterior surface is reduced, and the physical properties of the coating film are apt to be deteriorated.

Next, a method for manufacturing the electrodeposition coated member of the present invention shown in FIG. 2 will be described. First, a non-metallic substrate is plated, and a chemically colored film is formed. The non-metallic base material is not particularly limited, and plastic materials such as OA equipment and home electric appliances are used. For example, ABS resin, polycarbonate resin, polyetherimide resin, glass fiber-filled ABS resin, glass fiber-filled polycarbonate polyphenylene Oxide resins and the like are listed.

On a non-metallic substrate, a metal thin film is formed after etching and catalytic treatment, for example, palladium treatment, as performed by a generally known plating method on plastic.

The method of forming a metal thin film on a nonmetallic substrate is preferably performed by electroless copper plating, electrolytic plating, or the like.

Next, a chemically colored film is formed on the metal copper thin film. As a method for forming the chemically colored film, the surface of the metal thin film is chemically treated.

That is, when copper is used as the metal thin film, copper oxide, copper carbonate, copper sulfate,
A chemically colored film made of copper hydroxide ammonium, cuprous oxide, or the like can be formed.For example, as described above, when copper oxide having excellent adhesion of an electrodeposition film is used as a chemically colored coating, a substrate having a copper thin film is hydroxylated. It can be obtained by alkali treatment such as immersion in a sodium aqueous solution.

When an electrodeposition coating film is formed directly on a metallic copper thin film, copper dissolves and accumulates in the electrodeposition coating material and adversely affects the physical properties of the coating film. If a coating film is formed, dissolution of copper is prevented, and the presence of copper ions in the electrodeposition paint is not recognized.

Further, it is desirable that the chemical coloring layer is a thin film. In the present invention, a metal substrate other than a non-metal substrate can also be used as the substrate, and such a material includes
For example, copper, iron, Ni, zinc, tin and the like can be mentioned. In this case, a chemically colored film can be formed by directly treating the surface of the substrate, but when using a metal substrate other than copper, a chemically colored film of copper oxide can be formed by performing an oxidation treatment after applying copper plating to the surface. This is a preferred embodiment in that the following can be obtained, and the adhesion to the ED film is improved.

Next, the substrate provided with the chemically colored film is immersed in an electrodeposition paint to perform electrodeposition to form an electrodeposited film on the chemically colored film. This electrodeposition step may be performed according to a normal electrodeposition coating method. For example, when the electrodeposition resin is anionic, the base material is used as an anode, and when the electrodeposition resin is cationic, the base material side is used as a cathode. In the range of 20 to 25 ° C, the applied voltage 5
Electrodeposition is performed within a range of 0 to 200 V, a current density of 0.5 to 3 A / dm ² , and a processing time of 1 to 5 minutes to deposit resin and conductive particles on the chemically colored film.

The reason why the resin and the conductive particles are precipitated together at this time is considered as follows. That is, in the electrodepositable resin, the functional group bonded to the resin in the paint is ionized, and the resin is drawn to the object by applying a DC voltage between the object and the counter electrode. Precipitates. And since this resin is adsorbed around the conductive particles in the electrodeposition paint, the conductive particles also move with the movement of the resin to the object to be coated,
It precipitates together with the resin on the substrate.

Next, after washing with water, heat treatment is performed to cure the electrodeposited film. At this time, the curing temperature is, for example, 90 ° C. to 1 ° C. in an oven when metallized ceramic powder, metal natural mica or a mixture thereof is used as the conductive particles.
By curing at a low temperature of 00 ° C. for 20 to 180 minutes, sufficient curing can be achieved.

When ordinary metal powder, metallized resin powder or ultrafine metal powder is used, the
It is desirable to perform the heat treatment at 0 ° C.

In this way, an electrodeposited member is obtained which has been provided with an electromagnetic wave shielding property and an exterior coating simultaneously.

In the present invention, it is preferable that the thickness of the electrodeposition coating film is formed as thin as possible within a range where the shielding property can be ensured, from the viewpoint of uniformity, adhesion and cosmetic properties of the coating film. It is preferably from 7 to 40 μm, particularly preferably from 10 to 25 μm.

FIG. 4 shows an average particle diameter of 0.5 μm and 1 μm.
0.1μm on the surface of alumina powder of 3m, 3μm and 5μm
m of electroless copper plating was added to 15 parts by weight of 100 parts by weight of an acrylic melamine resin for electrodeposition (Hanibright C-IL; manufactured by Honey Chemical Co., Ltd.), and the solid content concentration was 15%. The center line average roughness (Ra) of the electrodeposition-coated member when the housing on which the base layer 5 was formed was immersed in the electrodeposition coating material diluted to a weight percent and electrodeposition was performed for 3 minutes while varying the applied voltage. / Μm) and the voltage, and the relationship between the thickness of the electrodeposited film and the voltage.

It can be seen from the figure that if the particle diameters are the same, the surface roughness increases as the applied voltage increases. On the other hand, the amount of eutectoid in the electrodeposited film of the conductive particles at this time was, for example, about 25% by weight at a voltage of 100 V regardless of the particle size.

FIG. 5 shows the average particle size (μ) of the conductive particles.
6 is a graph showing a relationship between a voltage with respect to m) and an average value (dB) of attenuation with respect to an electromagnetic wave of 50 to 1000 MHz. It can be seen from FIG. 5 that the shielding effect is improved as the voltage increases.

Further, the shielding effect is inversely proportional to the particle diameter. However, when the voltage is the same, the amount of eutectoid in the electrodeposited film is constant regardless of the particle diameter. It is considered that the relative number of the conductive particles in the deposited film was reduced, and the contact area between the particles was reduced.

From FIGS. 4 and 5, for example, the surface roughness R
In the case of obtaining an electrodeposition coating member with a = 1 μm and a shielding property of 70 dB, first, as shown in FIG. 4, the surface roughness is 40 V for a particle diameter of 5 μm, 77 V for 3 μm, 125 V for 1 μm,
A voltage of 200 V is required at 0.5 μm. On the other hand, as shown in FIG.
Since a voltage of 130 V or more for a particle size of 3 μm, a voltage of 95 V or more for a particle size of 1 μm, and a voltage of 65 V or more for a particle size of 0.5 μm is required, use a metallized ceramic powder having a particle size of 0.5 μm. It can be seen that a voltage of 200 V may be applied or a voltage of 125 V may be applied using metallized ceramic powder having a particle size of 1 μm.

Further, in addition to metallized ceramic powder or metallized natural mica as conductive particles, an average particle diameter of 0.01 to
When an ultrafine metal powder of about 5 μm is added, the surface roughness of the obtained electrodeposition coating member is dominated by the powder having the larger particle size and the amount of eutectoid.

For example, 8 parts by weight of a powder obtained by plating a 0.1 μm-thick copper powder on the surface of an alumina powder having an average particle diameter of 1 μm, and 10 parts by weight of a copper powder having an average particle diameter of 0.03 μm, In addition to 100 parts by weight of the melamine resin, when the solid content concentration was diluted to 15% by weight and electrodeposition was performed for 3 minutes, Ra
Is determined by the ratio of the metallized alumina powder to the eutectoid amount of the electrodeposited film. In this case, the amount of the metallized alumina powder deposited is 10% by weight, and the surface roughness as shown by the dotted line in FIG. An electrodeposition coated member is obtained.

When the mixed powder as described above is used, as described above, the electromagnetic wave shielding property is improved, and for example, the copper powder having a thickness of 0.1 μm is coated on the surface of the alumina powder having an average particle diameter of 1 μm. 10 parts by weight of plated powder and average particle size of 0.0
Acrylic melamine resin 1
In addition to 00 parts by weight, the solid content concentration was diluted to 15% by weight, and electrodeposition was performed for 3 minutes to form an electrodeposition coating member having an electrodeposition film having a film thickness of 20 μm and an eutectoid amount of 30% by weight. The shielding performance is as shown in FIG. 6, and it can be seen that the shielding effect is improved as compared with FIG.

As described above, according to the present invention, the particle size of the conductive particles, the applied voltage, and the content of the conductive particles in the electrodeposition paint are changed with respect to the required degree of matte finish and the electromagnetic wave shielding property. This can be dealt with by doing this.

For example, as shown in FIG. 7 and FIG. 8, by using for exterior coating of a housing 101 of an electronic device, it is possible to perform decorative coating of the housing surface and to impart electromagnetic wave shielding to the housing. it can.

[0063]

Next, the present invention will be described in detail with reference to examples.

In the following examples, the particle size of the powder was measured with a centrifugal sedimentation type particle size distribution analyzer (trade name: SACP-3; manufactured by Shimadzu Corporation). Were regarded as dense spheres of the same particle size.

The conductive particles in the electrodeposited film were identified by an X-ray microanalyzer, and the content was determined by a thermogravimetric analyzer (trade name: Thermal Analysis Sys.).
tem 7 series; PERKIN-ELMER
(Made by the company). Further, the electromagnetic wave shielding was performed by using a transmission line method (ASTM ES 7.83 method).

Example 1-1 The ABS resin case shown in FIG. 2 having a step and an apex angle on the surface was treated with a CrO ₃ —H ₂ SO ₄ —H ₂ O-based etchant for 1 minute, washed with water, The mixture was treated at room temperature for 2 minutes with 30 g / l of stannous chloride and 20 ml / l of hydrochloric acid as a sensitizer solution, and washed with water. Next, 0.3 g / l of palladium chloride and 3 ml / l of hydrochloric acid were used as an activator solution at room temperature for 2 minutes to conduct. Thereafter, plating was performed at a bath temperature of 70 ° C. for 3 minutes using an electroless copper plating solution (manufactured by Okuno Pharmaceutical Co., Ltd.) at pH 13.0 to form a copper thin film having a thickness of 0.2 μm. Then, sodium hydroxide 5
% And potassium persulfate 1% aqueous solution at 70 ° C. for 30 seconds to form a copper oxide film as a chemically colored film.

Then, based on 100 parts by weight of an acrylic / melamine resin (trade name: Hanibright C-IL, manufactured by Honey Chemical Co., Ltd.), electroless nickel plating was applied to a surface of alumina having an average particle diameter of 1 μm to a thickness of 0.2 μm. What was given to 1
After dispersing 5 parts by weight in a ball mill for 30 hours, the mixture was diluted to 15% by weight with demineralized water, and further used a coating liquid containing 2.0% by weight of carbon black for coloring.
Under the conditions of ° C. and pH 8 to 9, an object to be coated is used as an anode, a 0.5 t stainless steel plate is used as a counter electrode, and an applied voltage of 120 V is used.
For 3 minutes. After electrodeposition, washed with water, cured by heating in an oven at 97 ° C. ± 1 ° C. for 60 minutes to prepare an electrodeposition coating member having an electrodeposition film having a film thickness of 25 μm and a metalized alumina powder content of 20% by weight. Obtained.

This electrodeposited member was visually evaluated for appearance and measured for physical properties in accordance with JIS K6980. The results are shown in Table 1-2 and Table 1
3 is shown. As shown in the table, all are JIS standard or higher,
The electrodeposition coating member was excellent in appearance and physical properties of the coating film.

The thickness distribution of the electrodeposition coating film was calculated as follows:
The sections a to w shown in FIG. 2 were measured using a metal microscope manufactured by Olympus Optical. The results are shown in Table 1-1.
As shown in the table, the electrodeposition coating film is uniformly formed on the uneven portion in the thickness range of 24.7 to 26.0 μm.
The film thickness was almost the same as that of the flat portion 8.

The center line average roughness (Ra) of the surface of the electrodeposition coating film was 1.0 μm. The measurement of the center line average roughness of the surface was carried out by RANK TAYLOR HOBSON K. manufactured by Rank Taylor Hobson.
K. , Tallysurf type 6).

Further, when the electromagnetic wave shielding property of an electromagnetic wave having a frequency of 50 to 1000 MHz was measured according to the transmission line method, the attenuation was about 80 d.
B was good. As a result of this evaluation, it was confirmed that the method can be applied to high-quality satin-like exterior coating and coating for electromagnetic wave shielding.

[0072]

[Table 1]

Example 1-2 The thickness of the ABS resin housing used in Example 1-1 was reduced to 0.
After applying 7 μm of electroless copper plating, an electrodeposition coating member having an electrodeposition film having a film thickness of 20 μm and a metalized alumina powder content of 20 wt% was obtained in the same manner as in Example 1-1. About this electrodeposition coating member, appearance inspection, coating film physical properties, and electromagnetic shielding properties were evaluated in the same manner as in Example 1-1.

Example 1-3 The ABS resin casing used in Example 1-1 had a thickness of 0.7
After applying an electroless copper plating of 0.3 μm and then applying an electroless nickel plating to a thickness of 0.3 μm, a film thickness of 20 μm and a content of metallized alumina powder of 20 in the same manner as in Example 1-1.
An electrodeposition coating member having a wt% electrodeposition film was obtained. This electrodeposited member was evaluated for appearance inspection, coating film properties and electromagnetic shielding properties in the same manner as in Example 1-1.

Comparative Example 1 An electrodeposition coating was performed in the same manner as in Example 1-1 except that no metal alumina was added.

With respect to this electrodeposition coating member, Example 1-1
When evaluated in the same manner as in
It was less than 0 dB.

The appearance and physical properties of the coating film are as shown in Tables 1-2 and 1-3, and it is impossible to make the surface of the casing matte. It was unsuitable as a shield coating.

Comparative Example 2 50 parts by weight of the metallized alumina used in Example 1-1 were added to 50 parts by weight of an acrylic paint (No. 2026; Kansai Paint) with respect to the ABS resin casing used in Example 1-1. After the addition by weight and light mixing with a toluene solvent, the mixture was stirred with a homomixer for 10 minutes to prepare a spray paint.

Next, the above-mentioned spray paint was spray-applied to the ABS resin casing used in Example 1-1 to obtain a paint member having a spray paint film having a dried film thickness of 40 μm.
When this was evaluated in the same manner as in Example 1-1, the film thickness at the step portion and the apex portion was 5 μm as compared with the plane portion 8.
m or more, and the electromagnetic wave shielding property was 50 dB or less.

Evaluation of appearance (uniformity, see-through, stain, gloss / unevenness, flow, foreign matter and matte) of the coating films of Examples 1-1 to 1-3 and Comparative Examples 1 and 2, and coating films Tables 1-2 and 1-3 show the evaluation results of physical properties (adhesion, moisture resistance, accelerated light resistance, salt spray resistance, pencil hardness, alkali resistance and solvent resistance) and electromagnetic wave shielding properties.

[0081]

[Table 2]

(Note) The evaluation results are as follows. Sheer, stains, Tsuyamura, uniformity of flow, foreign matter satin of ◎ ·· not very good at all observed. Extremely uniform satining ○ ○ Good Almost no recognition. Uniform satin finish △ ・ ・ Slightly bad Partially recognized. Non-uniform satin × × bad Not matted

[0083]

[Table 3]

(Note) * 1: Salt spray resistance test: One-side blister width (mm) of coating film cut part * 2: RN: Rating number * 3: Electromagnetic wave shielding AA: Attenuation of 90 dB or more A : Attenuation amount of 80 dB or more and less than 90 dB B: Attenuation amount of 75 dB or more and less than 80 dB C: Attenuation amount of 70 dB or more and less than 75 dB D: Attenuation amount of 50 dB or less MEK: Methyl ethyl ketone

Example 1-4 The ABS resin case shown in FIG. 2 having a step or an apex angle on its surface was treated with a CrO ₃ —H ₂ SO ₄ —H ₂ O-based etching solution.
After treating with water for 30 minutes and washing with water, 30 g / l of stannous chloride and 20 ml / l of hydrochloric acid are used as a sensitizer solution at room temperature for 2 hours.
Treated for a minute and washed with water. Next, 0.3 g / l of palladium chloride and 3 ml / l of hydrochloric acid were used as an activator solution at room temperature for 2 minutes to conduct. Thereafter, plating was performed at a bath temperature of 70 ° C. for 3 minutes using an electroless copper plating solution (manufactured by Okuno Pharmaceutical Co., Ltd.) at pH 13.0 to form a copper thin film having a thickness of 0.2 μm. Then, sodium hydroxide 5
% And an aqueous solution of 1% potassium persulfate at 70 ° C. for 30 seconds to form a copper oxide film as a chemically colored film.

Then, an electroless copper plating of 0.2 μm was applied to the surface of silicon carbide having an average particle diameter of 1 μm with respect to 100 parts by weight of an acrylic / melamine resin (trade name: Hanibright C-IL, manufactured by Honey Chemical Co., Ltd.). After dispersing 15 parts by weight in a ball mill for 30 hours, the mixture
Using a coating solution diluted to 5% by weight and further added with 2.0% by weight of carbon black for coloring, a bath temperature of 25 ° C.
Under the condition of pH 8 to 9, the object to be coated is an anode, a 0.5 t stainless steel plate is used as a counter electrode, and an applied voltage of 150 V
Electrodeposited for minutes. After electrodeposition, it is washed with water and cured by heating in an oven at 97 ° C. ± 1 ° C. for 60 minutes to obtain an electrodeposition coated member having an electrodeposition film having a film thickness of 25 μm and a content of siliconized metal nitride of 30% by weight. Was.

The appearance of the coating film and the physical properties of the coating film were measured for the electrodeposition-coated member in the same manner as in Example 1-1 in accordance with JIS K5980. The result is shown in Example 1.
The same result as that of -1 was obtained.

The thickness distribution of the electrodeposition coating film was calculated as follows:
As a result of measurement by the same method as in Example 1-1,
As in the case of No. 1, the coating film was formed uniformly on the step portion and the apex portion, and had almost the same thickness as the flat portion 8.

The center line average roughness of the surface of the electrodeposition coating film was 1.5 μm. Furthermore, when the electromagnetic wave shielding property was measured in the same manner as in Example 1-1, the attenuation was about 85 dB. As a result of this evaluation, it was confirmed that the method can be applied to high-quality satin-like exterior coating and coating for electromagnetic wave shielding.

Example 1-5 The ABS resin case shown in FIG. 2 having a step or a vertex on the surface was treated with a CrO ₃ —H ₂ SO ₄ —H ₂ O-based etchant for 1 minute, washed with water, The mixture was treated at room temperature for 2 minutes with 30 g / l of stannous chloride and 20 ml / l of hydrochloric acid as a sensitizer solution, and washed with water. Next, 0.3 g / l of palladium chloride and 3 ml / l of hydrochloric acid were used as an activator solution at room temperature for 2 minutes to conduct. Thereafter, plating was performed at a bath temperature of 70 ° C. for 3 minutes using an electroless copper plating solution (manufactured by Okuno Pharmaceutical Co., Ltd.) at pH 13.0 to form a copper thin film having a thickness of 0.2 μm. Then, sodium hydroxide 5
% And an aqueous solution of 1% potassium persulfate at 70 ° C. for 30 seconds to form a copper oxide film as a chemically colored film.

Then, electroless nickel plating was applied on the surface of alumina having an average particle diameter of 0.5 μm to 0.2 μm with respect to 100 parts by weight of an acrylic / melamine resin (trade name: Hanibright C-IL, manufactured by Honey Chemical Co., Ltd.). 15 parts by weight were dispersed in a ball mill for 30 hours, diluted with demineralized water to 15% by weight, and further used 2.0% by weight of carbon black for coloring. Under the conditions of a bath temperature of 25 ° C. and a pH of 8 to 9, an object to be coated is used as an anode, a 0.5 t stainless steel plate is used as a counter electrode, and an applied voltage of 12
Electrodeposition was performed at 0 V for 3 minutes. After electrodeposition, wash with water, 97 ℃ ± 1 ℃
Cured by heating in an oven for 60 minutes, film thickness 20μ
m, an electrodeposition coating member having an electrodeposition film in which the amount of eutectoid metallized alumina was 22 wt%.

The appearance of the coating film and the physical properties of the coating film were measured on the electrodeposited member in the same manner as in Example 1-1 in accordance with JIS K5980. The result is shown in Example 1.
Same as -1, but with the same quality or better results as the conventional high temperature baking coating formed on metal.

The thickness distribution of the electrodeposition coating film was
As a result of measurement by the same method as in Example 1-1,
As in the case of No. 1, the coating film was formed evenly on the steps and the apical corners, and had almost the same thickness as the flat surface.

The center line average roughness of the surface of the electrodeposition coating film was 0.5 μm. Further, the attenuation of the electromagnetic wave shielding property was about 88 dB. As a result, it was recognized that the method can be applied to exterior coating and coating for electromagnetic wave shielding.

Example 1-6 An ABS resin case having a step or an apex angle on its surface was
Treated with an rO ₃ —H ₂ SO ₄ —H ₂ O-based etchant for 1 minute, washed with water, and then treated with stannous chloride 3 as a sensitizer solution.
The mixture was treated with 0 g / l and 20 ml / l hydrochloric acid at room temperature for 2 minutes and washed with water. Next, 0.3 g / l of palladium chloride and 3 ml / l of hydrochloric acid were used as an activator solution at room temperature for 2 minutes to conduct. Thereafter, the bath temperature was adjusted to 7 using an electroless copper plating solution (manufactured by Okuno Pharmaceutical Co., Ltd.) pH 13.0.
Plating was performed at 0 ° C. for 3 minutes to form a copper thin film having a thickness of 0.2 μm. Next, it was treated with an aqueous solution of 5% sodium hydroxide and 1% potassium persulfate at 70 ° C. for 30 seconds to form a copper oxide film as a chemically colored film.

Then, electroless copper plating of 0.2 μm was applied to the surface of silicon carbide having an average particle diameter of 5 μm with respect to 100 parts by weight of an acrylic / melamine resin (trade name: Hanibright C-IL, manufactured by Honey Chemical Co., Ltd.). After dispersing 15 parts by weight in a ball mill for 30 hours, the mixture
Using a coating solution diluted to 5% by weight and further added with 2.0% by weight of carbon black for coloring, a bath temperature of 25 ° C.
Under the condition of pH 8 to 9, the object to be coated is used as an anode, a 0.5 t stainless steel plate is used as a counter electrode, and an applied voltage of 170 V
Electrodeposited for minutes. After electrodeposition, it was washed with water and cured by heating in an oven at 97 ° C. ± 1 ° C. for 60 minutes to obtain an electrodeposition coated member having an electrodeposition film having a film thickness of 28 μm and a metalized silicon carbide content of 35 wt%. .

The appearance of the coating film and the physical properties of the coating film were measured on the electrodeposited member in the same manner as in Example 1-1 in accordance with JIS K5980. The result is shown in Example 1.
Same as -1, but with the same quality or better results as the conventional high temperature baking coating formed on metal.

The thickness distribution of the electrodeposition coating film was calculated as follows:
As a result of measurement by the same method as in Example 1-1,
As in the case of No. 1, the coating film was formed evenly on the steps and the apical corners, and had almost the same thickness as the flat surface.

The center line average roughness of the surface of the electrodeposition coating film was 5 μm. The electromagnetic wave shielding property is about 70
dB. As a result, it was recognized that the composition can be applied to exterior coating and coating for electromagnetic wave shielding.

Example 2-1 The ABS resin case shown in FIG. 2 having a step and an apex angle on the surface was treated with a CrO ₃ —H ₂ SO ₄ —H ₂ O-based etching solution for 1 minute, washed with water, The mixture was treated at room temperature for 2 minutes with 30 g / l of stannous chloride and 20 ml / l of hydrochloric acid as a sensitizer solution, and washed with water. Next, 0.3 g / l of palladium chloride and 3 ml / l of hydrochloric acid were used as an activator solution at room temperature for 2 minutes to conduct. Thereafter, plating was performed at a bath temperature of 70 ° C. for 3 minutes using an electroless copper plating solution (manufactured by Okuno Pharmaceutical Co., Ltd.) at pH 13.0 to form a copper thin film having a thickness of 0.2 μm. Then, sodium hydroxide 5
% And an aqueous solution of 1% potassium persulfate at 70 ° C. for 30 seconds to form a copper oxide film as a chemically colored film.

Then, 10 parts by weight of copper powder having an average particle diameter of 0.03 μm and 100 parts by weight of an acrylic / melamine resin (trade name: Hanibright C-IL, manufactured by Honey Chemical Co., Ltd.) 10 parts by weight of an electroless copper plating having a thickness of 0.2 μm on the surface of alumina was dispersed in a ball mill for 30 hours, then diluted with demineralized water to 15% by weight, and carbon black was further colored for coloring. 2.0
Bath temperature 25 ° C., pH 8-9
The electrode was electrodeposited at an applied voltage of 150 V for 3 minutes using an object to be coated as an anode and a 0.5 t stainless steel plate as a counter electrode under the conditions described in (1). After electrodeposition, wash with water and heat in an oven at 97 ° C ± 1 ° C for 60
The coating was cured by heating for about 1 minute to obtain an electrodeposition coating member having an electrodeposition film having a thickness of 25 μm and a content of metalized alumina powder and copper powder of 30 wt%.

This electrodeposition-coated member was made according to JIS K5980.
In accordance with, measurements of the appearance and physical properties of the coating film were performed. The results are shown in Tables 2-1 and 2-2. As shown in the table, all were electrodeposition coated members having a good appearance and excellent physical properties of the coating film, which were all JIS standard or higher.

The thickness distribution of the electrodeposited coating film was measured in the same manner as in Example 1-1, using a metal microscope manufactured by Olympus Optical Co., Ltd., and measuring the cross sections a through w shown in FIG. As a result, the variation in the film thickness was within ± 4%. Also,
The center line average roughness (Ra) of the surface of the electrodeposition coating film was 1.0 μm.

Further, when the electromagnetic wave shielding property was measured in the same manner as in Example 1-1, the attenuation was "AA" of 90 dB or more. As a result of this evaluation, it was recognized that the present invention can be applied to an exterior coating giving a high quality satin-like appearance and a coating for electromagnetic wave shielding.

[0105]

[Table 4]

[0106]

[Table 5]

Example 2-2 An ABS resin housing having a step or an apex angle on its surface was
Treated with an rO ₃ —H ₂ SO ₄ —H ₂ O-based etchant for 1 minute, washed with water, and then treated with stannous chloride 3 as a sensitizer solution.
The mixture was treated with 0 g / l and 20 ml / l hydrochloric acid at room temperature for 2 minutes and washed with water. Next, 0.3 g / l of palladium chloride and 3 ml / l of hydrochloric acid were used as an activator solution at room temperature for 2 minutes to conduct. Thereafter, the bath temperature was adjusted to 7 using an electroless copper plating solution (manufactured by Okuno Pharmaceutical Co., Ltd.) pH 13.0.
Plating was performed at 0 ° C. for 3 minutes to form a copper thin film having a thickness of 0.2 μm. Next, it was treated with an aqueous solution of 5% sodium hydroxide and 1% potassium persulfate at 70 ° C. for 30 seconds to form a copper oxide film as a chemically colored film.

Then, with respect to 100 parts by weight of an acrylic / melamine resin (trade name: Hanibright C-IL, manufactured by Honey Kasei Co., Ltd.), 7 parts by weight of copper powder having an average particle diameter of 0.05 μm and 1 part by weight of an average particle diameter of 1 μm were used. 8 parts by weight of an electroless copper plating having a thickness of 0.2 μm on the surface of silicon carbide is dispersed in a ball mill for 30 hours, and then diluted with deionized water to 15% by weight. Is applied at a bath temperature of 25 ° C. and a pH of 8 to 9 using a coating liquid containing 2.0% by weight of a coating material, a 0.5 t stainless steel plate as a counter electrode, and an applied voltage of 120 V for 3 minutes. Electrodeposited. After electrodeposition, the substrate was washed with water and cured by heating in an oven at 97 ° C. ± 1 ° C. for 60 minutes to obtain an electrodeposition coated member having an electrodeposition film having a film thickness of 20 μm and a powder mixture content of 20 wt%.

The appearance of the coating film and the physical properties of the coating film were measured on the electrodeposited member in the same manner as in Example 1-1 in accordance with JIS K5980. The result is shown in Example 2.
The same result as that of -1 was obtained.

Further, the thickness distribution of the electrodeposition coating film was calculated as follows.
As a result of measurement by the same method as in Example 1-1, Example 2-
As in the case of No. 1, the coating film was uniformly formed on the step portion and the apex corner portion, and had almost the same thickness as the flat portion 8. The center line average roughness of the surface of the electrodeposition coating film is 0.7 μm.
Met. As a result, it was recognized that the present invention can be applied to an exterior coating that gives a high-quality satin-like appearance and an electromagnetic shielding coating.

Example 2-3 An ABS resin case having a step or a vertex on its surface as shown in FIG. 2 was treated with a CrO ₃ —H ₂ SO ₄ —H ₂ O-based etchant for 1 minute, washed with water, The mixture was treated at room temperature for 2 minutes with 30 g / l of stannous chloride and 20 ml / l of hydrochloric acid as a sensitizer solution, and washed with water. Next, 0.3 g / l of palladium chloride and 3 ml / l of hydrochloric acid were used as an activator solution at room temperature for 2 minutes to conduct. Thereafter, plating was performed at a bath temperature of 70 ° C. for 3 minutes using an electroless copper plating solution (manufactured by Okuno Pharmaceutical Co., Ltd.) at pH 13.0 to form a copper thin film having a thickness of 0.2 μm. Then, sodium hydroxide 5
% And an aqueous solution of 1% potassium persulfate at 70 ° C. for 30 seconds to form a copper oxide film as a chemically colored film.

Then, 3 parts by weight of silver powder having an average particle diameter of 0.07 μm and 0.3 part by weight of an acrylic / melamine resin (trade name: Hanibright C-IL, manufactured by Honey Chemical Co., Ltd.) were added to 100 parts by weight. A 2 μm alumina surface coated with electroless nickel plating to a thickness of 0.2 μm, 7 parts by weight, dispersed in a ball mill for 30 hours, diluted with demineralized water to 15% by weight, and further carbonized for coloring Using a coating solution containing 2.0% by weight of black, a bath temperature of 25 ° C. and a pH of
Under the conditions of 8 to 9, the object to be coated was used as an anode, and as a counter electrode, 0.1% was used.
Using a 5t stainless steel plate, electrodeposition was performed at an applied voltage of 120 V for 3 minutes. After electrodeposition, wash with water and oven at 97 ℃ ± 1 ℃
The coating was cured by heating for 60 minutes to obtain an electrodeposition coating member having an electrodeposition film having a thickness of 20 μm and a mixed powder content of 30 wt%.

The appearance of the coating film and the physical properties of the coating film were measured on this electrodeposition coated member in the same manner as in Example 1-1 in accordance with JIS K5980. The result is shown in Example 2.
The same result as that of -1 was obtained.

The thickness distribution of the electrodeposition coating film was calculated as follows:
As a result of measurement by the same method as in Example 1-1, Example 2-
As in the case of No. 1, the coating film was uniformly formed on the step portion and the apex corner portion, and had almost the same thickness as the flat portion 8. The center line average roughness of the surface of the electrodeposition coating film is 0.3 μm.
Met. Furthermore, the electromagnetic wave shielding property was measured in the same manner as in Example 1-1, and as a result, the attenuation was "AA" of 90 dB or more. As a result, it was recognized that the present invention can be applied to an exterior coating that gives a fine satin-like appearance and an electromagnetic shielding coating.

Example 2-4 The ABS resin case shown in FIG. 2 having a step and an apex angle on the surface was treated with a CrO ₃ —H ₂ SO ₄ —H ₂ O-based etchant for 1 minute, washed with water, The mixture was treated at room temperature for 2 minutes with 30 g / l of stannous chloride and 20 ml / l of hydrochloric acid as a sensitizer solution, and washed with water. Next, 0.3 g / l of palladium chloride and 3 ml / l of hydrochloric acid were used as an activator solution at room temperature for 2 minutes to conduct. Thereafter, plating was performed at a bath temperature of 70 ° C. for 3 minutes using an electroless copper plating solution (manufactured by Okuno Pharmaceutical Co., Ltd.), pH 13.0, to form a copper thin film having a thickness of 0.2 μm. Then 5% sodium hydroxide,
The resultant was treated with a 1% aqueous solution of potassium persulfate at 70 ° C. for 30 seconds to form a chemically oxidized copper oxide film.

Then, 5 parts by weight of nickel powder having an average particle diameter of 0.03 μm and 0. 5 parts by weight of an acrylic / melamine resin (trade name: Hanibright C-IL, manufactured by Honey Chemical Co., Ltd.) were added to 100 parts by weight. 5 μm of silicon carbide surface is electroless copper-plated to a thickness of 0.2 μm, and 5 parts by weight are dispersed in a ball mill for 30 hours.
Weight%, and using a coating solution to which 2.0% by weight of carbon black was added for coloring, a bath temperature of 25 ° C. and a p.
Under the conditions of H8 to H9, the object to be coated was used as an anode, a 0.5 t stainless steel plate was used as a counter electrode, and an applied voltage of 200 V was used.
Electrodeposited for minutes. After the electrodeposition, the substrate was washed with water and cured by heating in an oven at 97 ° C. ± 1 ° C. for 60 minutes to obtain an electrodeposition coated member having an electrodeposition film having a thickness of 30 μm and a mixed powder content of 30% by weight.

The appearance of the coating film and the physical properties of the coating film were measured on the electrodeposition-coated member in the same manner as in Example 1-1 in accordance with JIS K5980. The result is shown in Example 2.
The same result as that of -1 was obtained.

The thickness distribution of the electrodeposition coating film was calculated as follows:
As a result of measurement by the same method as in Example 1-1, Example 2-
As in the case of No. 1, the coating film was uniformly formed on the step portion and the apex corner portion, and had almost the same thickness as the flat portion 8. The center line average roughness of the surface of the electrodeposition coating film is 0.5 μm.
Met. Further, with respect to the electromagnetic wave shielding property,
As a result of evaluation in the same manner as -1, an attenuation of 100 dB or more was obtained. As a result, it was recognized that the present invention can be applied to the exterior coating giving a satin appearance and the coating for electromagnetic wave shielding.

Example 3-1 An ABS resin case having a step and a vertex on the surface shown in FIG. 2 was treated with a CrO ₃ —H ₂ SO ₄ —H ₂ O-based etchant for 1 minute, washed with water, The mixture was treated at room temperature for 2 minutes with 30 g / l of stannous chloride and 20 ml / l of hydrochloric acid as a sensitizer solution, and washed with water. Next, 0.3 g / l of palladium chloride and 3 ml / l of hydrochloric acid were used as an activator solution at room temperature for 2 minutes to conduct. Thereafter, plating was performed at a bath temperature of 70 ° C. for 3 minutes using an electroless copper plating solution (manufactured by Okuno Pharmaceutical Co., Ltd.) at pH 13.0 to form a copper thin film having a thickness of 0.2 μm. Then, sodium hydroxide 5
% And an aqueous solution of 1% potassium persulfate at 70 ° C. for 30 seconds to form a copper oxide film as a chemically colored film.

Next, electroless copper plating was applied to the surface of natural mica having an average particle diameter of 2.0 μm with respect to 100 parts by weight of an acrylic / melamine resin (trade name: Hanibright C-IL, manufactured by Honey Kasei Co., Ltd.). After dispersing 15 parts by weight in a thickness of 0.05 μm with a ball mill for 30 hours, the mixture was diluted to 15% by weight with demineralized water, and further coated with 2.0% by weight of carbon black for coloring. Using, bath temperature 2
Under conditions of 5 ° C. and pH 8 to 9, the object to be coated is used as an anode, a 0.5 t stainless steel plate is used as a counter electrode, and an applied voltage of 120 is used.
Electrodeposited at V for 3 minutes. After electrodeposition, washed with water and cured by heating in an oven at 97 ° C. ± 1 ° C. for 60 minutes.
An electrodeposition coating member having an electrodeposition film having a mixed powder content of 20 wt% was obtained.

The appearance of the coating film and the physical properties of the coating film were measured on the electrodeposition-coated member in the same manner as in Example 1-1 in accordance with JIS K5980. Table 3-1 shows the results.
As shown in Table 3-2, the same results as in Example 1-1 were obtained.

The thickness distribution of the electrodeposition coating film was
As a result of measurement by the same method as in Example 1-1, the variation in the film thickness was within ± 4%, and the film was formed evenly on the step portion and the apex corner portion of the housing. It was a film thickness.

Further, the center line average roughness (Ra) of the surface of the electrodeposition coating film was 1.4 μm. Further, the electromagnetic wave shielding property showed an attenuation of about 75 dB. From these results, it was confirmed that the present invention can be applied to exterior coating for forming a high-quality satin-like appearance and coating for electromagnetic wave shielding.

Example 3-2 A copper thin film and a copper oxide film were formed on the ABS resin case shown in FIG. 2 having steps and apex angles on the surface in the same manner as in Example 4-1. As a coating solution, 5 parts by weight of nickel powder having an average particle diameter of 0.03 μm and 100 parts by weight of an acrylic / melamine resin (trade name: Hanibright C-IL, manufactured by Honey Chemical Co., Ltd.) and an average particle diameter of 1. 5 μm of natural mica is electroless nickel-plated to a thickness of 0.2 μm, and 10 parts by weight are dispersed in a ball mill for 30 hours, and then diluted with demineralized water to 15% by weight. Using a coating liquid to which 2.0% by weight of carbon black was added, at a bath temperature of 25 ° C. and a pH of 8 to 9, an object to be coated was used as an anode, a 0.5 t stainless steel plate was used as a counter electrode, and an applied voltage of 150 V was used. Electrodeposited for 3 minutes. After electrodeposition, wash with water, 9
The composition was cured by heating in an oven at 7 ° C. ± 1 ° C. for 60 minutes to obtain an electrodeposition coating member having an electrodeposition film having a thickness of 24 μm and a mixed powder content of 28 wt%.

With respect to this electrodeposition coating member, Example 1-1
The appearance and physical properties of the coating film were evaluated in the same manner as described above.
The results are shown in Table 3-1 and Table 3-2.

Further, the thickness distribution of the electrodeposition coating film was calculated as follows.
As a result of measurement by the same method as in Example 1-1, Example 3-
As in the case of No. 1, the coating film was formed uniformly at the step portion and the apex portion, and had almost the same thickness as the flat portion 8.

[0127] The center line average roughness (Ra) of the surface of the electrodeposition coating film was 1.2 µm. Further, the electromagnetic wave shielding property was an attenuation of 100 dB or more. As a result, it was recognized that the present invention can be applied to exterior coating for forming a high-quality satin-like appearance and coating for electromagnetic wave shielding.

Example 3-3 The ABS resin case shown in FIG. 2 having a step and an apex angle on the surface was treated with a CrO ₃ —H ₂ SO ₄ —H ₂ O-based etching solution for 1 minute, washed with water, The mixture was treated at room temperature for 2 minutes with 30 g / l of stannous chloride and 20 ml / l of hydrochloric acid as a sensitizer solution, and washed with water. Next, 0.3 g / l of palladium chloride and 3 ml / l of hydrochloric acid were used as an activator solution at room temperature for 2 minutes to conduct. Thereafter, plating was performed at a bath temperature of 70 ° C. for 3 minutes using an electroless copper plating solution (manufactured by Okuno Pharmaceutical Co., Ltd.) at pH 13.0 to form a copper thin film having a thickness of 0.2 μm. Then, sodium hydroxide 5
% And an aqueous solution of 1% potassium persulfate at 70 ° C. for 30 seconds to form a copper oxide film as a chemically colored film.

An acrylic / melamine resin (trade name: Hanibright C-IL, manufactured by Honey Kasei Co., Ltd.) was used as the electrodeposition coating liquid.
100 parts by weight, 3 parts by weight of silver powder having an average particle diameter of 0.07 μm, and 7% by weight of an electroless nickel plating having a thickness of 0.2 μm on the surface of alumina having an average particle diameter of 0.2 μm And 10 parts by weight of a surface of natural mica having an average particle diameter of 1.5 μm and electroless nickel plating having a thickness of 0.02 μm dispersed in a ball mill for 30 hours, and then 15% by weight with demineralized water. Using a coating liquid containing 2.0% by weight of carbon black for coloring, at a bath temperature of 25 ° C. and a pH of 8 to 9, the object to be coated was an anode, and a 0.5 t stainless steel was used as a counter electrode. Electrodeposition was performed using a plate at an applied voltage of 100 V for 3 minutes. After electrodeposition, wash with water, 97
The coating was cured by heating in an oven at a temperature of ± 1 ° C. for 60 minutes to obtain an electrodeposition coating member having an electrodeposition film having a thickness of 16 μm and a mixed powder content of 15 wt%.

[0130] The appearance of the coating film and the physical properties of the coating film were measured on the electrodeposition-coated member in the same manner as in Example 3-1 in accordance with JIS K5980. The results are shown in Table 3-1 and Table 3-2.

Further, the thickness distribution of the electrodeposition coating film was calculated as follows:
As a result of measurement by the same method as in Example 1-1, the coating film was formed uniformly at the step portion and the apex portion, and had almost the same thickness as the flat portion 8.

Further, the center line average roughness (Ra) of the surface of the electrodeposition coating film was 0.8 μm. Further, the electromagnetic wave shielding property showed an attenuation of about 90 dB. As a result, it was recognized that the present invention can be applied to exterior coating for forming a high-quality satin-like appearance and coating for electromagnetic wave shielding.

Example 3-4 The ABS resin case shown in FIG. 2 having a step and an apex angle on its surface was treated with a CrO ₃ —H ₂ SO ₄ —H ₂ O-based etchant for 1 minute, washed with water, The mixture was treated at room temperature for 2 minutes with 30 g / l of stannous chloride and 20 ml / l of hydrochloric acid as a sensitizer solution, and washed with water. Next, 0.3 g / l of palladium chloride and 3 ml / l of hydrochloric acid were used as an activator solution at room temperature for 2 minutes to conduct. Thereafter, plating was performed at a bath temperature of 70 ° C. for 3 minutes using an electroless copper plating solution (manufactured by Okuno Pharmaceutical Co., Ltd.) at pH 13.0 to form a copper thin film having a thickness of 0.2 μm. Next, the mixture was treated with a mixed solution of copper nitrate, ammonium chloride and acetic acid at 70 ° C. for 30 seconds to form a copper hydroxide coating.

Next, an electrodeposition coating liquid was applied to 100 parts by weight of an acrylic / melamine resin (trade name: Hanibright C-IL, manufactured by Honey Chemical Co., Ltd.) on the surface of silicon carbide having an average particle diameter of 0.5 μm. 15 parts by weight of electroless copper plating having a thickness of 0.2 μm and 15 parts by weight of electroless copper plating having a thickness of 0.2 μm on the surface of natural mica having an average particle diameter of 3 μm were subjected to ball milling. After dispersing for 30 hours, the mixture was diluted to 15% by weight with demineralized water, and further used a coating liquid containing 2.0% by weight of carbon black for coloring at a bath temperature of 25 ° C. and a pH of 8 to 9, The workpiece is the anode,
A 0.5t stainless steel plate was used as a counter electrode, and an applied voltage of 1
Electrodeposition was performed at 70 V for 3 minutes. Wash with water after electrodeposition, 97 ℃ ± 1
Cured by heating in an oven at 60 ° C for 60 minutes.
m, an electrodeposition coating member having an electrodeposition coating film having a mixed powder content of 25 wt% was obtained.

The appearance of the coating film and the physical properties of the coating film were evaluated for the electrodeposited coating member in the same manner as in Example 1-1 in accordance with JIS K5980. Table 3-1 shows the results.
As shown in Table 3-2, the electrodeposition coating member had a good appearance and excellent coating film properties.

The thickness distribution of the electrodeposited coating film was measured in the same manner as in Example 1-1. As a result, the variation in the film thickness was within ± 10%, and the thickness of the coating film was not more than ± 10%. And the film thickness was almost the same as that of the flat portion 8.

The center line average roughness (Ra) of the surface of the electrodeposition coating film was 3 μm. Further, the electromagnetic wave shielding property was 100 dB.

[0138]

[Table 6]

[0139]

[Table 7]

Reference Example 1 The ABS resin case shown in FIG. 2 having a step and an apex angle on the surface was treated with a CrO ₃ —H ₂ SO ₄ —H ₂ O-based etchant for 1 minute, washed with water, and then sensitized. The solution was treated with stannous chloride (30 g / l) and hydrochloric acid (20 ml / l) at room temperature for 2 minutes and washed with water. Then, as an activator liquid,
The mixture was treated with 0.3 g / l of palladium chloride and 3 ml / l of hydrochloric acid at room temperature for 2 minutes to make it conductive. Thereafter, plating was performed at a bath temperature of 70 ° C. for 3 minutes using an electroless copper plating solution (manufactured by Okuno Pharmaceutical Co., Ltd.) at pH 13.0 to form a copper thin film having a thickness of 0.2 μm. Then, the mixture was treated at 70 ° C. for 30 seconds in a mixed solution of copper sulfate and sodium chloride to form a cuprous oxide coating.

Then, 15 parts by weight of a copper powder having an average particle diameter of 0.02 μm was dispersed in a ball mill for 30 hours with respect to 100 parts by weight of an acrylic / melamine resin (trade name: Hanibright C-IL, manufactured by Honey Kasei Co., Ltd.). And then add 1
Using a coating solution diluted to 5% by weight and further added with 2.0% by weight of carbon black for coloring, a bath temperature of 25 ° C.
Under the condition of pH 8 to 9, the object to be coated is used as an anode, a 0.5 t stainless steel plate is used as a counter electrode, and an applied voltage of 3
Electrodeposited for minutes. After the electrodeposition, the electrodeposition was washed with water and cured by heating in an oven at 145 ° C. ± 1 ° C. for 60 minutes to obtain an electrodeposition coated member having an electrodeposition film having a film thickness of 27 μm and a powder content of 38 wt%.

[0142] This electrodeposition coating member was made according to JIS K5980.
In accordance with, measurements of the appearance and physical properties of the coating film were performed. The results are shown in Table 4-1 and Table 4-2. Moreover, the thickness distribution of the coating film of the electrodeposition coating film was measured for the cross sections a to w shown in FIG. 2 using a metal microscope manufactured by Olympus Optical Co., Ltd. As a result, the electrodeposition coating film was uniformly formed on the step portion and the apex portion, and had almost the same thickness as the flat portion 8. The center line average roughness (Ra) of the surface of the electrodeposition coating film was 0.3 μm. The measurement of the center line average roughness of the surface was performed using Talysurf type 6 manufactured by Taylor Hobson. Furthermore, electromagnetic wave shielding is about 70d
B.

[0143]

[Table 8]

[0144]

[Table 9]

[0145]

As described above, according to the electrodeposition coating member of the present invention, the surface of the casing having a step or an apex angle on the surface is covered with the electrodeposition coating film containing conductive particles. There is almost no difference in the thickness of the coating film between the stepped ridgeline or apex corner and the flat part of the casing, and the exterior can be coated uniformly, and the casing surface can be uniformly matted. Since it can be finished, the decorative appearance is remarkably improved, and it can greatly contribute to the application to the exterior and economically.

Further, by depositing conductive particles in the electrodeposited film, it is possible to impart an electromagnetic wave shielding property to the electrodeposited film, so that the electromagnetic wave shield of the housing and the exterior can be coated in one step.

Further, according to the present invention, the electromagnetic wave shielding property and the degree of matte finish on the casing surface are controlled by changing the content and particle size of the conductive particles in the electrodeposition film, the applied voltage and the electrodeposition time. Can be changed arbitrarily, and coating can be performed according to the use of the housing of the object to be coated.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing an example of the configuration of an electrodeposition coating member of the present invention.

FIG. 2 is a partial sectional view showing an example of a housing using the electrodeposition coating member of the present invention.

FIG. 3 is a schematic cross-sectional view schematically showing an electrodeposition coating film of the electrodeposition coating member of FIG.

FIG. 4 is a graph showing the relationship between the center line average roughness (Ra) of the surface of the electrodeposition coating film and the applied voltage for each average particle size of the metallized ceramic powder, and the applied voltage and the applied voltage. .

FIG. 5 is a graph showing a relationship between an electromagnetic shielding property and an applied voltage of an electrodeposition coating member having an electrodeposition film containing metalized ceramic powders having various average particle sizes.

FIG. 6 is a graph showing a relationship between an electromagnetic shielding property and an applied voltage of an electrodeposition coating member having an electrodeposition film containing a mixed powder of a metallized ceramic powder and an ultrafine metal powder.

FIG. 7 is a perspective view of a computer using the electrodeposition coating member of the present invention for a housing.

FIG. 8 is a partial cross-sectional view taken along the line AA of the housing of the computer in FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Non-metal member 2 Metal thin film 3 Chemical coloring film 4 Electrodeposition coating film 5 Underlayer 6 Ridge part 7 Apex corner part 8 Flat part

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁷ Identification symbol FI // C09D 5/44 C09D 5/44 AB (31) Priority claim number Japanese Patent Application No. 2-117498 (32) Priority date Heisei 2 May 9, 1990 (5.9.5.9) (33) Countries claiming priority Japan (JP) (58) Fields investigated (Int. Cl. ⁷ , DB name) C25D 15/00-15/02 C25D 13 / 00-13/20 H05K 5 / 00,9 / 00 C09D 5/44

Claims (10)

(57) [Claims] 1. A casing having a step or a vertex or both on a surface, wherein at least a ridge or a vertex of the step or both of the step has metalized ceramic powder and gold.
Contains at least one selected from genus mica powder
Electrodeposition coating member, characterized in that they are being coated with a conductive particles-containing to electrodeposition coating film formed by the outer coating. 2. A mixture of at least one selected from metalized resin powder and ultrafine metal powder in addition to at least one selected from metalized ceramic powder and metalized natural mica powder as the conductive particles. 2. The electrodeposition-coated member according to claim 1, containing a powder. 3. The electrodeposition coating member according to claim 1, wherein said housing is a housing of an electronic device. 4. An electrodeposition coating in which a casing having a step or an apex angle or both on the surface is coated with an electrodeposition coating film containing conductive particles at least on a ridge or an apex or both of the step. A method for manufacturing a member , comprising:
Or one selected from natural powder and metalized natural mica powder
Is immersed in an electrodeposition coating material containing conductive particles containing two kinds of powders and subjected to electrodeposition to obtain a surface roughness having a center line average roughness (Ra) of 0. A method for producing an electrodeposition-coated member, comprising: forming an electrodeposition coating having a value of 3 to 5 μm and having an electromagnetic wave shielding property on a surface of the housing. 5. The method according to claim 1, wherein the conductive particles are one or two selected from metalized ceramic powder and metalized natural mica powder, and one selected from metalized resin powder and ultrafine metal powder. 5. The method for producing an electrodeposition-coated member according to claim 4 , which is a mixture of seeds or two kinds of powders. 6. The method of claim wherein the housing is a housing of an electronic device
5. The method for producing an electrodeposition coated member according to 4 . After performing 7. electrodeposition to the housing, the manufacturing method of electrodeposition coating member according to claim 4, further comprising a step of curing the electrodeposition coating film by heating. 8. forming a metal plating layer on the non-metallic housing surface and then after forming a chemically colored layer by surface treatment of the plating layer to form a electrodeposition coating film on the chemical coloring layer 請
The method for producing an electrodeposition coated member according to claim 4 . 9. claims wherein the metal plating layer is copper-plated
Item 9. The method for producing an electrodeposition coated member according to Item 8 . Wherein said chemical colored layer is coating of copper oxide
A method for producing an electrodeposition coated member according to claim 8 .