JPH026564A - Electrodeposition coating material and electrodeposited member - Google Patents

Abstract

PURPOSE:To obtain the title coating material which can be completely cured even under low-temperature curing conditions and can give a coating film of improved strengths by mixing an electrodepositable resin with a ceramic powder and/or fluororesin powder each having a specified particle diameter. CONSTITUTION:An electrodeposition coating material is obtained by mixing 100 pts.wt. electrodepositable resin (a) (e.g., acryl melamine resin) with a ceramic powder (e.g., Al2O3) and/or a fluororesin powder (b) each having a mean particle diameter of 0.1-5mum. A substrate is treated with this coating material by using the substrate as an anode in an anionic system or as a cathode in a cationic system under conditions of a bath temperature of 20-30 deg.C, an applied voltage of 50-200V, a current density of 0.5-3A/dm<2> for 1-7min, washed with water, and cured for 20-120min in an oven at a temperature <=100 deg.C to obtain an electrodeposited member having a coating film of a thickness of 5-50mum.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Industrial Field of Application The present invention relates to an electrodeposition paint suitable for forming rough surfaces used in optical equipment such as cameras, office machines, audio products, home appliances, instruments, etc. and relating to electrodeposition coated members.

(2) Conventional technology Conventionally, in order to form an electrodeposition coating film with a rough surface, electrically neutral fine particles are usually added to the electrodeposition coating solution as described in Japanese Patent Publication No. 59-34799. For example, do not disperse ceramic powder, etc., and roughen the surface of the base material by special roughening pre-treatment or post-treatment after electrodeposition coating (so-called roughening treatment is performed in the same tank at the same time as electrodeposition coating). It is possible to form a coating film with a soft surface, and it can exhibit remarkable effects.

(3) Problems to be Solved by the Invention However, in recent years, the electrodeposition coating method has been shifting from the high temperature curing type described in the above-mentioned publication to the low temperature curing type.

This is because the base material for exterior use has become plastic, and the need for surface modification has increased, making it necessary to develop products for high-end products. For this reason, electrodeposition coating methods have been proposed for the purpose of surface modification as well as low-temperature curing, but in both cases, the coating film properties are lower than those of high-temperature curing types, and the degree of curing is lower, resulting in a decrease in quality and the versatility of the product. The deficit will be limited.

The object of the present invention is to provide a coating film that promotes and completely cures the coating film even under low-temperature curing conditions through the eutectoid effect of ceramic powder in the electrodeposition coating, and has physical properties equal to or better than that of high-temperature curing electrodeposition coatings. The object of the present invention is to provide an electrodeposition coating material that can form a transparent surface.

Another object of the present invention is to provide an electrodeposited member having an electrodeposited coating film with good physical strength.

(4) Means for Solving Problems The electrodeposition paint according to the present invention is a resin capable of electrodepositing a powder having an average particle size of 0.1 to 5 μm selected from electrodepositable resins, ceramic powders, and fluororesin powders. 10
It is characterized by containing 0.2 to 6 parts by weight relative to 0 parts by weight.

Further, the electrodeposition coated member according to the present invention has an average particle size of 0.0000.
It is characterized by having an electrodeposited coating film containing 0.5 to 50 wt% of powder of 1 to 5 μm.

By eutectoiding the ceramic powder and/or fluororesin powder with the resin component, the performance can be sufficiently achieved by increasing the curing to the same level as the high temperature curing type.

The performance of the electrodeposition paint according to the present invention is shown in FIG. 1, and typical embodiments of the electrodeposition coated member with rough surface are shown in FIGS. 2 and 3.

FIG. 1 is a current-time curve comparing the precipitation reactions of carbon black dispersed in a resin and ceramic powder dispersed on a nickel plating film.

The curve (■) in FIG. 1 is for the case where "resin (15 wt%) ten carbon (1.5 wt%)" of Example 1 is used, and the curves (2) and (2) are for each embodiment of the present invention. The voltage for electrodeposition treatment is 150V. From this graph, it can be confirmed that the electrodeposition coating film formed from the conductive paint of the present invention is dense and has excellent uniformity. That is, by dispersing and eutectoiding the ceramic powder, the curve becomes much closer to the x-axis than when the ceramic powder is not eutectoid. This behavior occurs because the membrane resistance is high and it is difficult for current to flow (in other words, the membrane quality is dense, which greatly contributes to the curing reaction. Also, the behavior does not change depending on the amount of ceramic powder. Not recognized,
The object of the present invention can be fully achieved within the range of 0.2 to 6 parts by weight based on 100 parts by weight of the resin.

FIG. 2 shows a case where a catalyst treatment layer 2 and a plating film 3 are formed on the surface of a plastic material 1 by a generally known plastic plating process to serve as a base material, and an electrodeposited member 4 is formed on the surface. FIG.

FIG. 3 is a cross-sectional view of a state in which a plating film 3 or a colored film is formed on the surface of a metal 5 by a generally known plating process or a coloring process to form a base material, and an electrodeposited member 4 is formed on the surface of the base material. be. However, the formation of a plating film or a colored film can be omitted if necessary.

In this way, the eutectoid effect of the ceramic powder or fluororesin powder on electrodeposition-coated parts significantly accelerates film hardening and achieves complete curing, resulting in not only hardness but also high scratch resistance, high solvent resistance, high weather resistance, and decorative properties. It is possible to form an electrodeposition coated member having the following properties.

A typical structure of the rough surface electrodeposition coated member of the present invention is that the base material is made of plastic or metal, and for plastics, copper plating or nickel plating is applied using a generally known plating process on plastic. Form to a thickness of ~30 μm.

For metals, it is formed in a generally known plating process or coloring process to a thickness of 3 to 20 μm for plating, and to a thickness of 3 μm or less for coloring. Furthermore, film formation can be omitted if necessary. For aluminum, anodizing treatment and the like can be mentioned.

Next, the rough surface electrodeposition coating member on the surface of the base material may be a resin containing a low temperature curing agent that is generally commercially available, and is preferably an acrylic resin, an acrylic melamine resin, an epoxy resin, or a urethane resin. Ceramic powder or fluororesin powder is dispersed in resin. Examples of ceramic powders include aluminum oxide, titanium nitride, manganese nitride, tungsten nitride, tungsten carbide, lanthanum nitride, aluminum silicate, molybdenum disulfide, titanium oxide, graphite, and silicate compounds.

Also, examples of resin powders include fluororesins.

If the particle size of the powder is large, the ratio to the resin content will increase, resulting in excessive curing and brittleness, causing particles to fall off and quality to deteriorate.The particle size is preferably 0.1 to 5 μm, particularly 1 to 3 μm. The particle size of this powder is a value measured using a centrifugal sedimentation type particle size distribution analyzer. The measuring device actually used was 5ACP-3 (trade name, manufactured by Shimabara Seisakusho).

If the amount of powder dispersed is large, it goes without saying that sedimentation will increase, but the ratio to the resin content will also increase, resulting in excessive curing, causing brittle powder particles to fall off, and degrading quality.

Moreover, if the amount of dispersion is small, the amount of resin will be large, and curing acceleration will be significantly reduced, which will also cause a decrease in quality. Therefore, resin 1
The powder is dispersed in an amount of 0.2 to 6 parts by weight, preferably 0.5 to 3 parts by weight per 00 parts by weight. As for the shape, it can be either fixed or amorphous, and after putting the specified amount of these into a container with resin and dispersing it in a ball mill for more than 24 hours, it is dispersed for 5 to 2 hours using demineralized water.
Diluted to 0 wt%, preferably in the range of 7-17 V/t%. After that, add pigment as necessary to pH 7.5.
Adjust to ~9.0.

Next, for anionic systems, the object to be coated is used as the anode, and for cationic systems, the object to be coated is used as the cathode, and the bath temperature is in the range of 20 to 30°C. If necessary, the applied voltage is 50 to 200 V, and the current density is 0.5 to 3 A/dr.
rl', treatment time is 1 to 7 minutes.

Then, after washing with water, it is cured and completed in an oven set at 100° C. or lower for 20 to 120 minutes. The thickness of the electrocoated member at this time can be any desired thickness, such as 5 to 50 μm. At this time, although curing progresses over time even at room temperature, it takes several days, which is not desirable in terms of work efficiency or work in progress.

0.5 to 50 wt% of powder is added to the electrodeposited film to be formed.
It is suitable to contain. Further, if the material is cured at a high temperature, for example, at a temperature of 120° C. or higher, the member becomes brittle due to overbaking.

As described above, in the present invention, by dispersing ceramic powder or fluororesin powder in a resin and forming an electrodeposited film, resin curing is significantly accelerated due to the powder eutectoid effect, and complete curing is possible, which is completely the same as that of a high temperature curing type. - or higher physical properties, such as hardness of 4 to 5 H1, solvent resistance, which remains unchanged against the most polar methyl, ethyl, and ketone, making it possible to demonstrate complete curing.

As the metal forming the base material, any metal such as iron, copper, zinc, nickel, aluminum, titanium, tungsten, chromium, or an alloy containing any of these metals can be used.

The present invention will be explained in more detail below according to examples.
The present invention is not limited to these embodiments.

Example-1 2% by weight of aluminum oxide and aluminum silicate particles with a particle size of 2 μm were separately added to 15 wt% of an acrylic/melamine resin clear stock solution (trade name: Honeybright C-IL, manufactured by Honey Kasei Co., Ltd.). After dispersing in a poly mill for 30 hours, diluted with demineralized water to a total volume of 1.5 w to obtain a black film.
A coating liquid was obtained by dispersing t% of carbon black. on the other hand,
In order to confirm the ceramic eutectoid effect, etc., the resin content was 15w.
A coating liquid in which 1.5 wt % of carbon black was added to t % was also obtained.

Using the electrocoating liquid obtained in this way, the electrocoating conditions were a bath temperature of 20 to 30°C, a pH of 8 to 9, the object to be coated as an anode, and a 0.5t stainless steel plate as the counter electrode. The test piece used for this is a plastic material (ABS) 50mm x 100mm x 0.5 under the condition that the voltage is increased at intervals of 25V from a minimum of 50V to a maximum of 200V.
After surface degreasing, Cr○, -H, So.

- Process for 1 minute using H30 type etching solution, then use 30g/j of stannous chloride as senmitizer solution! , concentrated hydrochloric acid 20 mA'/f! The surface was made conductive by catalytic treatment at room temperature for 2 minutes using electroless copper plating (trade name: 0PC700, manufactured by Okuno Pharmaceutical Industries, Ltd.) at pH 13.0 for 15 minutes at room temperature. Electrolytic nickel plating was performed using a bath at 5 A/drrr for 15 minutes to form a 15 μm film, which was used as a test piece.

This test piece was coated with mold coating for 2 minutes at each applied voltage, washed with water, desalted with water, and then coated with water for 9 days.
It was completed by baking for 30 minutes in a baking oven with an atmosphere of 7°C±1°C. After that, in order to confirm the degree of curing, hardness (pencil), solvent resistance (MEK), and scratch resistance (eraser) were measured. The above-mentioned excellent effects were demonstrated.

In addition, the coating film did not have the expected effect from the resin content and carbon black bath.

Example-2 For acrylic/melamine resin clear stock solution 15% (trade name Honeybright C-IL manufactured by Honey Kasei Co., Ltd.),
Tungsten carbide, titanium nitride, aluminum silicate, particles with a particle size of 5 μm were separately added at 5% by weight, dispersed in a ball mill for 30 hours, and then diluted with demineralized water to a total volume of 11. Furthermore, in order to obtain a black film, 1.5 wt % of carbon black was added to prepare an electrodeposition coating liquid.

Using the electrocoating paint obtained in this way, the electrocoating conditions were a bath temperature of 20 to 30°C, a pH of 8 to 9, the object to be coated as an anode, and a counter electrode of 0.00%. 5 Using a stainless steel plate, the applied voltage conditions are 25V each at a minimum of 50V and a maximum of 200V.
It rose at intervals of V.

The test piece used for this is a brass plate of 50m x 10
Electrolytic nickel plating was performed using a Watts bath at 5A/drrf for 15 minutes using 0mX0.5.
A film of m was formed and used as a test piece.

For this test piece, 2 for each applied voltage.
After applying the minute-type coating, it is washed with water, then washed with demineralized water,
Thereafter, the product was baked for 30 minutes in a baking oven with an atmosphere of 97°C±1°C. After that, in order to confirm the degree of curing, hardness (pencil), solvent resistance (MEK), and scratch resistance (eraser) were measured. The above-mentioned excellent effects were demonstrated.

(5) Effects of the invention As described above, the present invention significantly accelerates the curing reaction despite the low-temperature curing electrodeposition coating due to the eutectoid effect in the coating film due to the dispersion of ceramic powder and fluororesin powder.
Moreover, it is possible to provide an electrocoated member with a rough surface that can be completely cured and has the same or better effects than conventional high-temperature curing type coatings.

[Brief explanation of the drawing]

FIG. 1 shows the characteristics of ceramic powder due to the precipitation reaction as a current-time curve. Figures 2 and 3 each show an embodiment of a rough surfaced electrocoated member according to the present invention, and Figure 2 shows a state in which a plating film is formed on a plastic and an electrocoated film is formed on the surface. It is a cross section. FIG. 3 is a cross-sectional view of a state in which a plating film is formed on a metal and an electrodeposition coating film is formed thereon. 1...Plastic 2...Catalyst treatment layer 3...Plated film Electron Haruma prayer! Fish-time curve 4...electrodeposition coating film 5...metal

Claims (2)

[Claims] (1) Electrodepositable resin, ceramic powder and fluororesin powder are selected with an average particle size of 0.1 to 5 μm
of powder per 100 parts by weight of resin that can be electrodeposited.
An electrodeposition paint characterized by containing 2 to 6 parts by weight. (2) 0.5 μm of powder with an average particle size of 0.1 to 5 μm selected from ceramic powder and fluororesin powder
An electrodeposition coated member characterized by having an electrodeposition coating film containing ~50 wt%.