JPS61103580A - Coating process of deal - Google Patents

Abstract

PURPOSE:To obtain improved finished condition of a painted surface by forming a base layer by ejecting a powder paint to the surface of a deal after a heating stage at high temp. then forming a finished layer by ejecting another powder paint to the surface of the above-described base layer after a heating stage at intermediate temp. CONSTITUTION:In the heating stage I, III and V, a metallic receiving tray 1 for electrostatic painting and a wooden deal W are heated successively at high, intermediate, and low temp. while mounting the deal W as an object to be painted on the receiving tray 1. Further, in the initial electrostatic painting stage II, a powder paint P1 is ejected onto the surface 8 of the deal W after the high temp. heating stage I to form a base layer 9 on the surface 8. Further more, in the final electrostatic painting stage IV, a powder paint P2 is ejected onto the surface 9a of the base layer 9 after an intermediate temp. heating stage III to finish a finished layer 10. As the result, generation of small projections or crease due to air is not caused even for a wooden deal and the finished condition of a painted surface is improved.

Description

[Detailed description of the invention] The present invention relates to a method for coating plate materials.

Generally, when the plate material to be painted is made of wood, there is a problem in that since the plate material has air permeability, the paint film after painting swells due to air, and many small protrusions are likely to occur on the painted surface. These small projections significantly deteriorate the appearance quality of the object to be painted.

The purpose of the present invention is to solve these problems, and to provide a method for painting wooden boards that does not produce small protrusions or wrinkles caused by air, and provides an extremely good finish on the painted surface. shall be. Therefore, the feature of the present invention is that the metal receiver for electrostatic coating can hold the wooden board as the object to be coated on the panel and heat the stone and board at high, medium, and low temperatures. Each heating process of heating sequentially [I] [I
II] (V), an initial electrostatic coating process (ff) for spraying powdered paint onto the surface of the board to form a base layer on the surface after the high-temperature heating process [!], and a medium-temperature heating process After (II[), a powdered paint is sprayed onto the surface of the base layer to form a finishing layer on the surface (IV).

EMBODIMENT OF THE INVENTION Hereinafter, the present invention will be explained in detail based on drawings showing examples.

FIG. 1 is a simplified diagram of an apparatus used in the method for coating plate materials according to the present invention. In the figure, 1... is a board made of a metal plate with a thickness of about 2 fl that enables electrostatic coating of iron, steel, copper, etc., and is connected to an endless conveying means 2, for example, and is connected to an arrow A. Move circularly in the direction. 3, 4.5 are heating furnaces for high temperature, medium temperature, and low temperature, which are arranged in the moving path of the board 1, and the receiver is a high temperature heating furnace in the moving direction A of the board 1. Furnace 3, medium temperature heating furnace 4, and low temperature heating furnace 5 are arranged in this order. 6 is a paint injection device such as a spray gun, which is disposed between the high-temperature heating furnace 3 and the medium-temperature heating furnace 4, and sprays the base powder paint P1 onto the plate material W as the object to be coated on the receiving panel 1; is a paint spraying device such as a spray gun, which is disposed between the medium-temperature heating furnace 4 and the low-temperature heating furnace 5, and sprays the powdered paint P2 for finishing onto the plate material W on the receiving board 1. In addition,
The board material W may be a thick board of various types of plywood (including those in which a thin board of cypress wood or the like is attached to the base surface) or other wood. Further, as the base powder paint P1, a polyethylene resin fine powder paint with particles of 30 μ to 100 μ or less, such as the trade name “Atomer” (manufactured by Mitsui Oil Co., Ltd.), is used, and as the finishing powder paint P2, is a polyethylene resin powder coating with particles of 200μ to 300μ, such as the product name “Hizesox” (manufactured by Mitsui Oil Co., Ltd.)
is used.

Next, the coating method will be explained step by step using FIGS. 1 and 2. First, the plate material W is placed on the support plate 1 and sent into the high temperature heating furnace 3 which is the high temperature heating step [I]. The support plate 1 and the plate material W are heated in the heating furnace 3 to a high temperature of 200°C to 250°C, preferably 220°C to 230°C.

Next, the platen 1 and the plate material W heated to a high temperature are transported to an initial electrostatic coating process (n) outside the furnace. The electrostatic coating process (
In n), electrostatic coating is performed by spraying the fine powder paint P1 onto the surface 8 of the board W using the paint spraying device 6. This is possible because it is on board 1. That is, the injection device 6
By applying a high voltage between them, with the plate 1 as the cathode and the plate 1 as the anode, the scattered fine powder paint P1 is charged, is attracted to the surface 8 of the plate material W, and enters the eyes. Start fusing.

Next, the receiver is sent to the medium temperature heating furnace 4, which is the medium temperature heating process [■]. The receiver is heated to 150°C to 200°C, preferably 170°C to 200°C, in order to maintain the temperature necessary for fusing the powder paint P1.
It is heated by a medium temperature atmosphere of 180°C. As a result, the powdered paint P1 is completely fused to form a film-like base layer 9 on the surface 8 of the plate material W.

Next, the heated receiver plate 1 and the plate material W are sent to the latter stage electrostatic coating process (IV) outside the furnace, and the powdered paint P2 is applied to the base layer 9 of the plate material W by the paint sprayer 7.

Electrostatic coating is performed by spraying onto the 0 surface 9a. Electrostatic coating in this case can also be done by the plate 1, and as described above, the powdered paint P2 charged during scattering is attracted to the surface 9a of the base layer 9 and begins to fuse.

Thereafter, the receiver 1 and the plate material W are sent to a low-temperature heating furnace 5 which is a low-temperature heating process [■], and heated to 120°C in the heating furnace 5 to maintain the temperature necessary for fusing the powdered paint P2. ~1
It is heated in an atmosphere of 50'C, preferably 130C to 140C. As a result, the powdered paint P2 is completely fused to form a film-like finishing layer 10. With the above steps, the coating is completed, and the plate material W is taken out from the board 1 outside the furnace. FIG. 3 shows a cross-sectional view of the plate material W after painting is completed.

According to the coating method explained above, the coating is powdered paint PI.
, P2, and because the plate material W is heated before and after painting, air in the plate material W adheres to the powdered paint PL and P2 attached to the plate material W in the process of fusion and solidification. Powdered paint P1. The molten paint is diffused through P2, and moreover, when the plate W cools down, the molten paint is adsorbed onto the surface 8 of the plate W. Therefore, the solidified base layer 9 and finishing layer 10 do not bulge in the form of small bubbles due to air.

Furthermore, the finishing layer 10 formed of the powdered paint P2 made of polyethylene resin has properties such that other objects do not adhere to the painted surface 10a and it is hard to stain. When painted on plywood, it has the advantage of being easy to peel off from concrete. Further, the above-mentioned coating method is suitable for coating plywood made of thin sheets of natural wood such as cypress, cherry tree, and nara, and the transparent coating makes use of the grain of the material, that is, the natural wood.

The present invention has effectively achieved its intended purpose with the configuration detailed above. In particular, for metal wheat for electrostatic coating, the wooden board W as the object to be coated is placed on the board 1, and the receiver lA1
and each heating step CI) (III) (V) in which the plate material W is sequentially heated to high temperature, medium temperature, and low temperature, and high temperature heating step (1
) Later, after an initial electrostatic coating step (II) in which powdered paint P1 is sprayed onto the surface 8 of the plate material W to form a base layer 9 on the surface 8, and after a medium temperature heating step (III), the powdered paint P1 is Since the second electrostatic coating step (IV) includes spraying the paint P2 onto the surface 9a of the base layer 9 to form the finish layer 10 on the surface 9a, air is applied to the base layer 9 and the finish layer 10. This eliminates the possibility of small protrusions caused by air on the painted surface, which is the case with thermal transfer of film or painting with liquid paint. Furthermore, wrinkles do not occur during thermal transfer of the film, and a coated surface 10'a that is uniform throughout and has an excellent surface finish can be obtained. moreover,
The base layer 9 is completely adhered to the surface 8 of the plate material W to form a strong adhesive state, and together with the finishing layer 10, the surface 8 of the plate material W is reliably protected.

[Brief explanation of the drawing]

Fig. 1 is a simplified side view showing an example of an apparatus for carrying out the coating method according to the present invention, Fig. 2 is a sectional view showing an example of the method of the present invention in the order of steps, and Fig. 3 is a diagram showing the process after completion of painting. It is a sectional view showing a part of plate material. 1...Base is board, 8...Surface 1.9...Base layer, 9
a...-Surface, 10... Finishing layer, W... Board material, PI
, P2... powder paint, [I]... high temperature heating step,
(II)...Initial electrostatic coating process, CIII)...Medium temperature heating process, (IV)...Late electrostatic coating process, (V)
...Low temperature heating process.

Claims (1)

[Claims] 1. With a wooden board W as an object to be coated placed on a metal receiving board 1 for electrostatic coating, the receiving board 1 and the board W are sequentially heated to high temperature, medium temperature, and low temperature. Each heating process〔I〕〔
III] [V] and the initial electrostatic coating step [II] for spraying the powdered paint P1 onto the surface 8 of the plate material W to form the base layer 9 on the surface 8 after the high-temperature heating step [I] and a late electrostatic coating step [IV] for spraying powdered paint P2 onto the surface 9a of the base layer 9 to form a finishing layer 10 on the surface 9a after the medium temperature heating step [III]. How to paint board materials.