JPH09276755A - Ion electrostatic coating method and ion electrostatic coating booth - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely dedust the coating face of a body to be coated in spray coating and to form a high-quality coating film without any nonuniform coating by conducting spray coating in the atmosphere of the forced feed air neutrally ionized by a corona discharge. SOLUTION: Coating is conducted in a working space 1H in the atmosphere of the forced feed air and forced exhaust air respectively formed by a sucking device 1X and an exhauster 1Y. In this case, an ion is injected into the working space 1H from each blowoff nozzle of an ion generator 6 to decompose the molecule in the air into a neutralized ion, and the neutralized ion is entrained by the forced feed air and sent to the coating face of of a body T to be coated. Consequently, dust is not deposited on the coating face of the body T, and the unstable plus electron of the paint grain is converted into the stabilized one having both poles clue to the spray coating in the atmosphere of the neutrally ionized forced feed air, and the paint grains attract one another and are orderly deposited on the body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is capable of forming a more advanced coating film with less defects in spray coating various products or parts (hereinafter referred to as objects to be coated). The present invention relates to a possible ionizing coating method and an ionizing coating booth.

[0002]

2. Description of the Related Art Generally, an object (non-conductor) in the air
Is charged due to static electricity, so that the surface of the object T to be coated is charged in a state where positive and negative electrons are irregularly arranged as shown in FIG.
As shown in, the dust (floating dust) in the air was attracted and adhered to the surface of the object T to be coated.

If the object T to be coated in the charged state is spray-coated in a normal atmosphere as it is, dust on the surface of the object T will cause defective coating.
Before painting, the surface of the object T to be coated was blown with air or brushed to remove dust.
When air blow or brushing is performed, there is a problem that the electrification power on the surface of the object is rather increased due to air friction and the opposite effect is obtained.

Therefore, the surface of the object T to be coated is dusted by corona discharge air blow in the pre-process of coating, or the entire working space for coating is humidified (generally, the humidity is 70%). It was considered that the coating is performed after the static-free state has been obtained by applying a temperature of 20 ° C.).

[0005]

However, the dust removal countermeasure by corona discharge air blow is effective during the air blow process, but at the end of the process, the object T to be coated starts to be charged with static electricity again, and Since the charged state shown in FIG. 7 is returned again at the start point, the problem of dust adhesion could not be fundamentally solved.

In addition, with respect to the antistatic measures by the humidification, an environment in which mold is most likely to occur is taken into consideration when considering the environment, so that the atmosphere adheres to the inner wall surface of the work space (booth) or the space There was a problem that mold floating inside had an adverse effect on the health of workers.

On the other hand, regarding the finish state of the spray coating, the spray-atomized paint particles potentially have positive electrons, and are unstable with a single electron, so that OH- in the air as shown in FIG. It stabilizes by oxidatively bonding to the base, but most of the paint particles reach the object to be coated T in the state shown in FIG. 7 before neutralization due to the velocity of the spray air, and as shown in FIG. There is a problem in that this phenomenon is combined with negative electrons on the object T side and repulsed with positive electrons, and this phenomenon basically forms unevenness of the coating film, resulting in uneven coating (yuzu skin, scaly, etc.).

In addition, the repelled paint particles in FIG. 10 have the bonded state shown in FIG. 9, and the bonded paint particles are applied to the surface of the coating film formed in FIG. There is a problem that uneven coating is generated on the surface of the coating film, resulting in a very poor finish.

Therefore, the technical problem of the present invention is to apply a spraying method to surely remove the coated surface of an object to be coated so as to form a high-quality coating film which is clean and has no coating unevenness. And to provide a painting booth.

[0010]

[Means for Solving the Problems] Means taken in the present invention for solving the above technical problems are as follows.

(1) Spray coating in a forced-air atmosphere neutralized and ionized by corona discharge.

(2) Before spray coating in an atmosphere of forced air that has been neutralized and ionized by corona discharge, use a tool such as a spray to apply either cations or anions to the coated surface of the object to be coated. Applying

(3) A coating booth in which an intake device and an exhaust device are connected in a working space for coating to perform the coating work in an atmosphere of filtered forced air supply. An air chamber isolated by a filter top plate made of punching metal or wire mesh is connected to the upper surface of the space, and the air intake device is connected to the air chamber while the upper surface of the filter top plate is connected. Shall be provided with an ion generating tube, and the ion blowing nozzle should be projected toward the above working space from the air outlet opened on the filter top plate.

(4) The distance between the ion blowing nozzle of the ion generating tube and the object to be coated set in the working space is set at least within the range of 1.5 to 2.5 m.

According to the means described in the above (1), the corona discharge decomposes the molecules in the air to generate neutralization ions sharing positive and negative electrons, and the neutralization ions are forcedly supplied. Reach the coated surface of the object to be coated,
Since the painted surface can be made to be in a state of being charged to "0" by attracting it with the oppositely charged ions, it is possible to prevent dust from adhering to the painted surface.

Further, according to the means described in the above (1), since the spray paint is performed in the atmosphere, the unstable positive electrons of the paint particles are converted into stable ones having both electrodes by the ions, Since the same principle that the opposite poles of the magnetic force work together causes the paint particles to attract each other and to be aligned and applied, and this state is continued during painting, so there is no unevenness on the application surface. It is possible to form a coating film having high density, high adhesion and good quality.

According to the means described in (2) above, either cations or anions are applied in advance to the coating surface of the object to be coated before spray coating, and the ions on the coating surface are in the same state. Therefore, if spray coating is performed in this state, it is possible to apply all the paint particles converted to a stable state with both poles in a completely aligned state with the same pole facing the same direction. Therefore, it is possible to form a coating film which is excellent in finish and extremely stable and of high quality.

According to the means described in the above (3), by ejecting ions from the blowout nozzle of the ion generator toward the working space, the molecules in the air are decomposed to generate neutralized ions. Is made to reach the coating surface of the object to be coated by forced air supply by the intake device and the exhaust device, and a state of charging "0" is created, and since spray coating is performed in this atmosphere, the paint particles attract each other. Since the coating is performed in line, it is possible to form a coating film of good quality with no irregularities on the coating surface.

According to the means described in the above (4), the ions ejected from the ion generator can be diffused into the flow of the forced air supply, and even if the ion effect is sufficiently exerted, the spray is carried out. Makes it possible to reliably proceed with painting.

As described above, the above (1) to
The technical problem described above can be solved by means described in (4), and the problem of the conventional technology can be solved.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of an ion static control coating method and an ion static control coating booth according to the present invention will be described.
A detailed description will be given with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view for explaining the internal structure of a booth for ion-rectifying coating according to the present invention. The inside of the booth generally designated by reference numeral 1 is a working space 1H,
An air chamber 4 isolated by a metal filter top plate 7 having a large number of ventilation holes 7a, such as punching metal or wire net, is continuously provided on the upper surface of the working space 1H.
The air chamber 4 includes an air supply chamber 2a and an air supply fan (not shown).
1X including an air supply fan chamber 2 having a built-in fan and an air supply filter chamber 3 having a primary air supply filter
Is connected via the flexible hose 2b,
The working space 1H is configured to forcibly supply the filtered air.

Reference numeral 5 denotes a secondary air supply filter provided inside the air chamber 4, and 6R denotes a filter chamber which is separated from the upper and lower sides by the secondary air supply filter 5 and the filter top plate 7 described above.
Is an ion generator attached to the upper surface of the filter top plate 7 in the filtration chamber 6R, and as shown in the configuration diagram of FIG. The ion ejection nozzles 6T ...
As shown in the cross-sectional view of FIG. 3, the outlets 7H opened in the filter top plate 7 project toward the working space 1H.

In FIGS. 1 and 2, S is a workbench provided in the work space 1H, T ... is an object to be coated placed on the workbench S, and the ion blowing nozzle 6T and the object to be coated T are provided. As shown in FIG. 2, the distance between and is such that ions can be sufficiently diffused into the flow of the forced supply air flowing into the working space 1H through the respective ventilation holes 7a of the filter top plate 7 described above, and It is set within the range of 1.5 to 2.5 m so that a sufficient ion effect can be given to the coated object T.

Further, SA is a spray coater for coating the object T to be coated in the working space 1H in the atmosphere of forced air supply, and SB is before spray coating by the spray coater SA. An ion sprayer for applying either cations or anions to the coating surface of the object T to be coated to align the ions on the coating surface to the same pole as shown in FIG. Also, a handy type spraying by hand is described, but both of them may be configured automatically by a robot, and the selection thereof is arbitrary.

Further, in FIG. 1, 8 is the above-mentioned work space 1
The curtain that separates H from the exhaust passage 8A, and 8T is the exhaust passage 8
A water tank provided on the lower side of A, 11 and 11 are fluorescent lamps for lighting, and an exhaust fan chamber 10 having a shower 8S, an illuminator 9, and an exhaust fan (not shown) built in on the exhaust passage 8A. The exhaust device 1Y including the above is provided, and is configured to exert an exhaust action on the work space 1H.

Since the present invention has the configuration as described above,
The painting work performed in the work space 1H is performed in the atmosphere of forced air supply and forced exhaust by the intake device 1X and the exhaust device 1Y. In the present invention, in particular, each blowout of the ion generator 6 ... From the nozzle 6T to the above working space 1H
As shown in FIG. 3, the ions injected toward the inside decompose molecules in the air to become neutralization ions, and the neutralization ions are put on the above-mentioned forced air supply and the coated surface of the object T to be coated. Therefore, the coated surface of the object T to be coated can be brought into a state of being charged “0”, that is, a dust-removed state in which dust does not adhere.

In addition, in the present invention, since the spray coating is performed in the neutralized and ionized forced air supply atmosphere as described above, the unstable positive electrons of the paint particles are converted into ions having a stable bipolar electrode. Then, since the surface of the object T to be coated in the above-mentioned charged "0" state is coated with the stably converted paint particles, the same principle that magnetic force counter electrodes attract each other as shown in FIG. 4 is exerted. , The paint particles are neatly applied while being attracted to each other.

The coating film subjected to the ionizing coating as described above is formed by the suction principle shown in FIG. 4 in a stable state having upright unevenness, high density and high adhesiveness, and flatness and gloss. It was found that the degree and hardness can be improved.

Incidentally, the results of the paint coating test of the radiator grill conducted on February 14, 1996 at the Gunma Industrial Research Institute are as follows. 60 ° specular reflectance gloss test ... Conventional product ・ 7
5.6 °, product of the present invention 78.8 °. Hardness test using a pencil scratch tester ... Conventional product H
B, product of the present invention-H. Film thickness test using an optical microscope (400x) ... Conventional product, 25μ, Inventive product, 30μ.

Further, according to claim 2 of the present invention, before the spray coating is performed in the atmosphere of the neutralized and ionized forced air supply, as shown in FIG. Or, one of the negative ions (anion in the case of drawing) is sprayed to align the ions on the coating surface in the same state. Therefore, spray coating in this aligned state will convert it to a stable state with both poles. As shown in Fig. 6, the coating particles can be applied to the coating surface in a completely aligned state with all the same poles facing in the same direction, so the finished state is very good and the stability and quality are higher. Can be formed.

The above-mentioned method of spraying cations or anions onto the surface to be coated in advance, even when it is carried out as a pretreatment step of electrostatic coating using an electrostatic coating machine, gloss, film thickness, An excellent effect can be exhibited in terms of hardness.

[0033]

As described above, according to the ionizing method and the ionizing booth according to the present invention, it is possible to form a more advanced coating film with few defects in the finished product,
Unlike the coating film formed by general coating, the coating film formed by the present invention does not have an OH-group, so that a very stable coating film can be formed, and it does not change even when forcedly dried. Therefore, it has an excellent feature that neither peeling due to an oxidation phenomenon nor a trace of a bubble state is observed.

[Brief description of drawings]

FIG. 1 is a front cross-sectional view illustrating the configuration of a booth for ion-rectifying coating according to the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part of the booth shown in FIG.

FIG. 3 is an explanatory diagram illustrating a principle of setting a coated surface to a charged “0” state by neutralizing ions generated by corona discharge.

FIG. 4 is an explanatory diagram for explaining a coating state of paint particles by ion voltage regulation coating.

FIG. 5 is an explanatory diagram illustrating a state in which ions on a coated surface are aligned in the same pole.

FIG. 6 is an explanatory diagram illustrating a coating state of paint particles when ions on a coating surface are aligned in the same pole.

FIG. 7 is an explanatory diagram illustrating a charged state of an object to be coated.

FIG. 8 is an explanatory diagram illustrating the principle of dust adhesion due to static electricity.

FIG. 9 is an explanatory diagram illustrating a state of neutralization bonding of paint particles in air.

FIG. 10 is an explanatory diagram illustrating the principle that unevenness of a coating film is basically formed during conventional coating.

[Explanation of symbols]

 1 Coating booth 1H Working space 1X Air supply device 1Y Exhaust device 4 Air chamber 6 Ion generator 6T Ion blowing nozzle 7 Filter top plate 7a Vent hole 7H Air outlet T Painted object SA Spray coater SB Ion atomizer

Claims (4)

[Claims] 1. An ion-conditioning coating method, which comprises spray-coating in an atmosphere of forced air neutralized and ionized by corona discharge. 2. The ion preparation according to claim 1, wherein before the spray coating, either cations or anions are applied to the coating surface of the object to be coated using a tool such as a spray. Electric coating method. 3. A coating booth in which an intake device and an exhaust device are connected to a working space for painting so that painting work is carried out in an atmosphere of filtered forced air supply. An air chamber isolated by a filter top plate made of punching metal or wire mesh is connected to the upper surface of the air chamber, and the intake device is connected to the air chamber while the upper surface of the filter top plate is connected to the air chamber. An ion voltage adjusting coating booth characterized in that an ion generating tube is provided, and an ion blowing nozzle thereof projects from an outlet opening on a filter top plate toward the above working space. 4. The distance between the ion blowing nozzle of the ion generating tube and the object to be coated set in the working space is set at least within a range of 1.5 to 2.5 m. The booth for ionization coating described in 3.