KR100733843B1 - Powder coating method of mdf substrate - Google Patents

Abstract

Provided is an powder coating method of a non-conductive MDF substrate with help of a good conductor net to maximize electrostatic adhesion of the powder, resulting in improved smoothness and reduced powder recovery rate. The apparatus of powder coating of an MDF substrate is constituted by a conveyor(10) at the center, and an automatic coating gun(20) and a paint precipitator(30) which are disposed in a manner to cross each other from both sides of the conveyor(10). The coating gun(20) coats the MDF substrate in a vertical direction, while the MDF substrate moving in a horizontal direction(left-to-right or right-to-left) by the conveyor(10). In addition, a grid shape good conductor net(4) is installed 50cm away from the rear surface of the MDF substrate.

Description

Powder coating method for MDF material {Powder coating method of MDF substrate}

1 is a plan view showing a powder coating device of the present invention.

Figure 2 is a front view showing a powder coating device of the present invention.

Figure 3 is a side view showing a state of use of the grid-shaped good conductor network of the present invention.

※ Explanation of code for main part of drawing

2: MDF 4: lattice good conductor network

10: conveyor 20: automatic coating gun

30: paint dust collector

The present invention relates to a method of coating the MDF substrate with a powder coating, a grid-type conductor network on the back of the MDF substrate during spray coating to increase the electrostatic force on the MDF non-conductor after moving the MDF into the powder coating booth by a conveyor MDF material that can be installed and painted to maximize the electrostatic adhesion of powder coating powder to eliminate unpainted parts on MDF surface and increase smoothness, as well as to reduce the powder recovery rate of powder to increase the coating area per unit area It relates to a method of painting with paint.

Conventionally, in order to coat powder coating on MDF, when MDF on the conveyor reaches the position of powder electrostatic coating gun by manual method or automatic method using electrostatic powder coating gun, corona or tribo gun, non-conducting MDF Powder coating was spray-coated on.

However, the coating method as described above, although there is a slight difference depending on the type of powder electrostatic coating gun, there is a limit in attracting the electrostatic attraction of the powder in the non-conductive MDF.

It is absorbed by the MDF during powder coating hardening due to the decrease in the amount of adhesion of the powder, and only the amount of coating remaining on the surface is not enough to cope with products requiring high smoothness due to the lack of substantial coating thickness on the MDF surface. The sand texture shows the application of the paint. In particular, it has been difficult to fundamentally solve the unpainted portion generated at the corners of the MDF.

This technical problem causes the paint user to excessively spray the MDF, which causes a drastic deterioration of the paint productivity. Also, excessive paint is used to coat the MDF. There was a problem that caused a problem of an increase in the coating cost per unit area of the MDF.

The present invention has been made in order to solve the above problems, a grid-type conductor network is installed on the back of the MDF holding spray when spray coating to increase the electrostatic force on the MDF non-conductor after moving the MDF to the powder coating booth with a conveyor Powder coating powder to maximize the electrostatic adhesion of the powder coating powder to remove unpainted parts on the surface of the MDF and increase the smoothness, as well as to reduce the powder recovery rate of the powder to increase the coating area per unit area The purpose is to provide a method for painting.

In order to achieve the above object, the present invention, in the method of coating the powder coating with a powder corona gun or tribo electrostatic spray paint gun on the MDF that the grid-shaped conductor network is installed at a distance within 50cm of the back surface of the MDF coating It features.

Hereinafter, the configuration of the present invention with reference to the accompanying drawings as follows.

1 is a plan view showing a powder coating apparatus of the present invention, Figure 2 is a cross-sectional view showing a powder coating apparatus of the present invention, Figure 3 is a side view showing a state of use of the grid-type good conductor network of the present invention.

First, with reference to Figures 1 and 2 shown briefly described in powder coating apparatus is configured to cross the automatic coating gun 20 and the paint dust collector 30 on both sides around the conveyor (10).

The powder electrostatic spray gun used for powder coating is applied to the upper and lower parts of the MDF 2 by manual or automatic, and the MDF 2 is moved from left to right or right to left by a conveyor.

Referring to the configuration shown with reference to Figure 3 shown in the distance between the MDF (2) moved by a conveyor located in front of the powder electrostatic coating gun 10 ~ 50cm and spaced within 50cm on the rear to the MDF (2) In the state consists of a grid 10cm ~ 400cm, 10cm ~ 400cm in size and a grid-shaped conductor network (4) according to the internal size of the powder coating booth.

At this time, the upper, lower, left, and right lattice spacing of the lattice-shaped conductor network 4 has an inner diameter of 20 cm or less, and the diameter of the conductors constituting the lattice-shaped conductor network 4 is 1 mm to 30 mm, and the material has a resistance value of 10¹Ω · It is a good conductor less than or equal to cm and is formed to be grounded.

When spraying the powder coating in the powder coating booth through the device consisting of powder coating in the possession of the MDF (2) as described above, the electrostatic force is induced to the MDF (2) that is a non-conductor to the MDF (2) The amount of powder is increased, and the powder coating film thickness and the coating area are widened, resulting in the effect of preventing the unpainted portion from occurring on the surface of the MDF 2 base.

On the other hand, the composition of the powder coating used to coat the MDF (2) with the powder coating is as follows. 70 wt% of unsaturated polyester resin UVECOAT3001 (SK-CYTEC Co., Ltd.), 5 wt% of smoothing agent RESIFLOW PV88 (Boli Co.), 0.5 wt% of pinhole inhibitor BENZOIN (unfinished yarn), and UV photoinitiator IRGACURE 2959 (Ciba Specialty Co., Ltd.) 2 wt% Then, 22.5 wt% of a white pigment TIO2 R-706 (DuPont) is placed in a premixing tank.

Next, after mixing the powder coating composition put into the premixing tank to melt disperse at a temperature of 80 ~ 100 ℃ of the melt extrusion disperser to produce a chip (CHIP) and to produce the chip with an average particle size of 38 ~ 42㎛ by a high-speed grinding machine Using a corona powder electrostatic spray gun, fixed at 60KV voltage, powder coating discharge rate 2.0 bar, air volume 2.5 bar, distance 25cm between MDF holder, 30cm width × 30cm × 1.8cm thickness, and 25cm distance between grid-type good conductor network After the fermentation, the mass of the powder is measured using an electronic balance, and an embodiment thereof is as follows.

Hereinafter, the present invention will be described through Examples and Comparative Examples as follows, and the scope of the present invention is not limited to the Examples.

In the first embodiment, powder electrostatic coating is performed in powder coating booths using a grid-shaped stainless steel mesh having a width of 40 cm and a width of 40 cm, and a grid thickness of 1 cm and a grid thickness of 3 mm.

In the second embodiment, powder electrostatic coating is performed in powder coating booths by using a grid-shaped stainless steel mesh having a width of 40 cm and a width of 40 cm, and a grid thickness of 3 cm and a thickness of the grid being 3 mm in diameter.

In the third embodiment, powder electrostatic coating is performed in a powder coating booth using a grid copper mesh having a size of 40 cm and a width of 40 cm, and a grid thickness of 3 cm and a grid of 3 mm in diameter.

In the fourth embodiment, powder electrostatic coating is performed in powder coating booths using a grid wire mesh having a size of 40 cm and a width of 40 cm, and a grid thickness of 1 cm and a grid of 1 mm in diameter.

Comparative Example 1 performs powder electrostatic coating in a powder coating booth by a conventional method with nothing behind the MDF 2.

In Comparative Example 2, after installing 40 cm wide, 40 cm long and 1 mm thick iron plates on the rear 25 cm of the MDF (2), powder electrostatic coating was performed in the powder coating booth.

In Comparative Example 3, powder electrostatic coating is performed in a powder coating booth by using a 25 cm wide and 20 cm long grid-shaped wire mesh having a thickness of 3 cm and a diameter of 3 cm.

In Comparative Example 4, powder electrostatic coating is performed in a powder coating booth by using a 25 cm wide and 40 cm long grid having a thickness of 25 mm and a 25 cm grid having a thickness of 3 mm.

Comparative Example 5 is to apply powder electrostatic coating in powder coating booth, using 25cm width of 40cm and 40cm length of grid wire mesh with 0.5mm diameter of 3cm grid thickness of MDF (2). same.

According to Examples 1 to 4 and Comparative Examples 1 to 5, after coating the powder coating on the MDF substrate, the mass, coating area, and cleaning property of the powder were measured, and the results are shown in the following table. Same as

First, the electrostatic attraction test is to hold the powder electrostatic coating gun at a distance of 25cm to the MDF fixedly mounted on the center of the MDF, and to install the test specimens at 25cm intervals on the back of the MDF, and then apply 100g of powder coating for 10 seconds. The powder is continuously sprayed onto a 30 cm × 30 cm × 1.8 cm thick MDF, and the mass difference between the pure MDF and the coated MDF is measured using a balance.

Second, the coating area test is made of 30cm long, 30cm long, 1.8cm thick MDF with 29 horizontal lines and 29 vertical lines at 1cm intervals from left to right and top to bottom to give serial numbers 1 to 29 and then powder Check the position number of the line that the powder exerts, and compare the relative application area of the powder by numerical value.

Third, the cleanability test records the time when the cleaning is finished by forcibly cleaning with a compressor air that the powder sprayed by the powder electrostatic spray gun is attached to the grid and the plate fixedly installed on the rear surface of the MDF (2). Compare.

As shown in the table, Examples 1 to 4 applying the method of coating the MDF base material with the powder coating according to the present invention, after coating the coating grid on the back of the MDF when MDF is coated with the powder coating powder to the electrostatic coating The method of coating powder coating on a conventional MDF by installing a lattice-shaped conductor network composed of a conductor material having good electrical properties such as stainless, iron, and copper mesh as the mass of the pure powder on the rear surface of the MDF. The difference in the weight mass attached to the surface of the MDF shows that the adhesion of the powder to the MDF increases much better than the comparative example of spray coating without installing anything on the back of the MDF.

Examples 1 and 2 and 3 show that the material of the lattice network is conductive and produces a similar electrostatic attraction force when the gap between the lattice networks is maintained. Although it induces adhesion amount, it takes a long time to clean and inconvenient point that causes contamination to other paints when insufficient cleaning occurs, and when laminating the non-conductor MDF (2) through Comparative Example 3, the grid installed on the back The size of the type conductor network must be equal to or larger than that of the base to have a sufficient effect.Comparative Example 4 shows that the grid type conductor network has little electrostatic attraction if the internal spacing of the grid type conductor network is above a certain level. there was.

In addition, it can be confirmed that the thickness of the lattice-shaped good conductor network should be above a certain level to induce electrostatic attraction.

According to the present invention, the electrostatic adhesiveness of the powder coating powder by installing and coating a lattice-type conductor network on the back of the MDF when spray coating to increase the electrostatic force on the non-conductive MDF after moving the MDF into the powder coating booth by a conveyor By maximizing the removal of unpainted parts on the surface of the MDF and increasing the smoothness, it is possible to increase the coating area per unit area by reducing the powder recovery rate of the powder.

Claims (3)

In the method for coating the powder coating on the MDF (2) with a corona gun or a powder electrostatic spray paint gun, Powder coating method for the MDF holdings, characterized in that the grid-shaped conductor network (4) is installed at a distance within 50cm of the rear portion of the MDF (2) coating. The method of claim 1, wherein the lattice good conductor network 4 10cm ~ 300cm, 10cm ~ 300cm in length and the diameter of the thickness of the good conductor network is powder coating method for MDF holding, characterized in that formed in 1mm ~ 20mm. The grid-shaped good conductor network 4 according to claim 1 or 2, A powder coating method for MDF substrates, characterized in that the upper, lower, left and right lattice spacing is less than 20cm in inner diameter and the material is electrically conductive with resistance of less than 10¹Ω · cm and is used in contact with the ground.

Images