JPH0663469A - Vacuum painting machine - Google Patents

Abstract

PURPOSE:To simplify the change of a color and to prevent the deterioration of the appearance of a coating surface even when aqueous paint is bonded to the inner wall of a vacuum painting machine by wholly or almost applying a water repelling film to the part coming into contact with aqueous paint of the inner wall of the vacuum painting machine in applying the aqueous paint. CONSTITUTION:In applying aqueous paint 10, the part coming into contact with the aqueous paint 10 of the inner wall of a vacuum painting machine to be used is wholly or almost coated with a water repelling film. This water repelling film has surface characteristics easy to repel water and, as the contact part with the aqueous paint 10, the inner wall parts of a painting chamber main body 1, a paint tank 2, a paint recovery tower 3 and a paint pressure feed pump 4 are designated and, further, the pipes 5 communicating with them or the storage part of the aqueous paint 10 in the lower part of the painting chamber main body 1 and the upper space part 12 thereof is designated. By this constitution, the aqueous paint is less apt to adhere to the inner wall of the vacuum painting machine and the bonded aqueous paint is easily washed and does not grow in size.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum coating machine useful for coating water-based paint.

[0002]

2. Description of the Related Art A vacuum coating machine is a coating machine known per se in which a coloring agent is atomized in a depressurized container, and a coating is passed through the coating to paint. It is applied to paint application. However, since the inner wall of this vacuum coating machine is mainly made of stainless steel, it is difficult to clean the inner wall of the coating machine at the time of color change, and the paint droplets gradually grow while growing on the inner wall. It has a defect that it comes in contact with the painted surface and deteriorates the finished appearance.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned defects in a pressure reducing coating machine useful for coating water-based paints. All or most of the portion that comes into contact with the water-based paint is coated with a water-repellent coating, and as a result, the above objects can be achieved and the present invention has been completed.

That is, according to the present invention, when a water-based paint is applied using a vacuum coating machine, all or most of the inner wall of the vacuum coating machine which comes into contact with the water-based coating is coated with a water-repellent coating. The present invention relates to a vacuum coating machine characterized by being coated.

The aqueous paint that can be used in the present invention is a composition containing a vehicle component, a coloring component and water as main components. As the vehicle component, for example, a room temperature-curable or heat-curable resin composition for coating material which is known per se and which is easily dissolved or dispersed in water can be used. Specific examples include acrylic resins, urethane resins, polyester resins, epoxy resins, and various modified resins based on these resins. These are cross-linking functional groups (for example, hydroxyl group, carboxyl group, glycidyl group). Groups and isocyanate groups). As these crosslinking agents, melamine resins and polyisocyanate compounds (including blocked compounds) are preferable. The coloring component is
Ordinary color pigments for paints, dyes, metallic pigments, etc. can be applied, and extender pigments can be used together. Furthermore, if necessary, it is difficult to evaporate under reduced pressure, for example, the boiling point is 100 ° C
A small amount of the above organic solvent may be contained.

With respect to the above-mentioned water-based paint used in the present invention, the viscosity is 7 to 30 seconds / Iwata cup / 20 ° C., particularly 7 to 10 seconds / Iwata cup / 20 ° C., and the solid content is 10-40 weight. %, Especially 20 to 30% by weight are suitable.

The vacuum coating machine used in the present invention is
A coating machine known per se, which passes an article to be coated in a decompression container in which the atomized colorant is floating, and coats the article to be coated with the atomized colorant, It has already been used for coating organic solution-based UV curable paints.

The outline of the vacuum coating machine used in the present invention is as shown in FIG. 1, and will be described with reference to FIG.
The decompression type coating machine is mainly composed of a coating chamber body (1), a paint tank (2), a paint recovery tower (3) and a paint pressure pump (4).
Which are connected to each other by a pipe (5). In addition, the water-based paint (1
0) is pumped, and a space (12) is provided above it.

First, the water-based paint (10) is pressure-fed from the paint tank (2) to the lower portion of the coating chamber body (1) by the pressure feed pump (4), and a space (12) is formed above it. The space (12) above the coating chamber main body (1) is always adjusted to a decompressed state, and the internal pressure thereof can be arbitrarily selected according to the purpose, but is usually about 100 to 500 mbar, particularly 200 to 350 mbar. It is preferable to adjust the range to. The depressurizing operation is performed by a known means, but for example, it is preferable to use a vacuum pump or the like.
Since the space portion (12) of the coating chamber body (1) is held in a depressurized state in this manner, the water-based paint (1
0) is volatilized in the form of mist, and is suspended in the space (12).

Further, the space portion (1) of the coating chamber body (1)
When the article (14) to be coated is inserted into the space (12) through the insertion opening (16) provided so as to directly communicate with the space (2), the floating colorant (10) is removed in the space (12). It is adsorbed on the article to be coated (14) and coating is performed. Then, thereafter, the article to be coated (14) is taken out from the take-out port (18) provided on the other side of the space portion (12).

A feature of the present invention resides in that all or most of the inner wall of the vacuum coating machine which comes into contact with the water-based paint is covered with a water-repellent coating.

The water-repellent coating is a coating having a surface property that easily repels water. For example, a fluororesin, a silicone resin, a polypropylene resin, a polyester resin, a glass reinforced resin (FRP) or the like is applied in a film state. It can be formed by wearing or by applying it in a liquid state. The thickness of the coating can be arbitrarily selected, but generally, a range of 10 μm to 1 mm is desirable.

In the present invention, the portion coated with the water-repellent coating is all or most of the inner wall of the vacuum coating machine which comes into contact with the water-based coating material.
The coating chamber main body (1), the paint tank (2), the paint recovery tower (3), and the paint pressure pump (4) inner wall part are mentioned, and the pipe (5) and the lower part of the paint chamber main body (1) that communicate with each other are mentioned. The water paint (10) storage part and the space part (12) above it are raised.

According to this method, since the inner wall of the vacuum coating machine is coated with the water-repellent coating, the water-based coating is unlikely to adhere, and even if it adheres, it can be easily washed by washing with water, so that the color can be changed. It is easy to do, and even if the water-based paint adheres to the inner wall, its size does not grow, so that the appearance of the coated surface is not deteriorated. It was possible to remove all the above-mentioned conventional defects.

In the present invention, the water-based paint (10) which has not been applied to the article to be coated (14) in the main body of the coating chamber (1) is pressure-fed to the paint recovery tower (3) together with the air flow, and there the water-based paint ( 10) is separated by a baffle plate (22), a filter (24), etc. and collected in a paint tank (2).

In the method of coating the coating material (14) with the water-based coating material (10) using a vacuum coating machine, considering that the collected water-based coating material (10) is mixed in the coating material tank (2). Water-based paint (1
It is preferable to control so that 0) always has a constant composition, viscosity and solid content. Further, the article (14) to be coated can be continuously carried into the space portion (12) of the coating chamber body (1) by a belt conveyor or the like. The surface of the article to be coated (14) is preferably as flat as possible, but slight unevenness (within a depth of about 2 cm) may be acceptable.

In the present invention, the water-based paint (10) is applied to the article (14) using a vacuum coating machine, and then dried and cured by an appropriate method depending on the composition of the water-based paint (10). Further, it is preferable that the clear coating is further overcoated so that the finished appearance and weather resistance are improved.

[0018]

EXAMPLES Examples of the present invention will be described. Examples and Comparative Examples A 0.1 mm-thick tetrafluoroethylene resin sheet is attached to the stainless steel inner wall surfaces of the paint recovery tower (3) and the coating chamber body (1). Next, a water-based colored paint containing acrylic resin and melamine resin as the main components, the viscosity of which was adjusted to 8 seconds / Iwata cup / 20 ° C. and the solid content rate of 25% by weight, was applied from the paint tank (2) to the painting chamber by the pressure pump (4). It is pumped to the bottom of the body (1) and the pressure in the space (12) is adjusted to about 300 mbar. Coating was performed in this state, and after 1, 2 and 4 hours had passed, the washability of the coating chamber body (1) and the finished appearance of the coated product were examined. The results are shown in Table 1.

[0019]

[Table 1]

In Table 1, the comparative example shows the results for the stainless inner wall surface when the tetrafluoroethylene resin sheet was not attached. Detergency: A result of the ease of cleaning the inner wall, indicates that cleaning is much easier than in the past, Δ indicates the same as in the past, and x indicates that cleaning was required for a long time. Finished appearance: indicates that the surface is painted, and is good, and x is inferior in smoothness.

[Brief description of drawings]

FIG. 1 is a schematic view of a vacuum coating machine used in the present invention.

[Explanation of Codes] 1: Main body of coating room 2: Paint tank 3: Paint recovery tower 4: Paint pump 5: Pipe 10: Colorant 12: Space part 14: Porous material 16: Insertion port 18: Outlet port 20: Gap 22: Baffle board

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Mikio Matsumoto 33-1 Kanzaki-cho, Amagasaki-shi, Hyogo Kansai Paint Co., Ltd.

Claims (1)

[Claims] 1. When coating a water-based paint using a vacuum coating machine, all or most of the inner wall of the vacuum coating machine that comes into contact with the water-based coating is coated with a water-repellent coating. A decompression coating machine characterized by that.