JP2006068645A - Production method for coated plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production method for a coated plate with little disturbance of discharge pattern of a coating material by suppressing variation in a discharge pressure of the coating material, and easy in forming a desired pattern. <P>SOLUTION: In this production method for the coated plate, the coating material 2 with multiple colors is sprayed onto the surface of a continuously carried metal plate 1 from one spray port 45 of a coating gun 3 while switching the spray port 45, to form a coating film. The coating material 2 is supplied to the coating gun 3 from a coating material tank 4 and sprayed, while unsprayed coating material is returned and circulated to the coating material tank 4. Even if the coating material 2 supplied to the coating gun 3 is not sprayed, the coating material 2 can be passed through without staying in the coating gun 3, to prevent accumulation of pressure of the coating material 2 in the coating gun 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a coated plate used as a building material such as a roofing material or a wall material, and is particularly suitably used for producing a painted plate having various and high design properties.

  2. Description of the Related Art Conventionally, a paint film having a variety of patterns has been formed by spray coating two or more colors on a belt-like object moving at a speed of 10 m / min or more (for example, Patent Document 1). reference). In the coating method described in Patent Document 1, at least two or more paint discharge nozzles are sequentially switched and discharged from at least two different paint colors, whereby the paint discharged from each paint discharge nozzle is A mixed color spray pattern is formed.

However, since the above paint is pressurized by the pump and supplied to the paint discharge nozzle, when multiple colors of paint are sequentially switched from the paint discharge nozzle and discharged, the paint that is not discharged is forced into the paint discharge nozzle. The pressure accumulated in the paint at the time of subsequent discharge is released instantly, and as a result, the discharge pressure of the paint changes and the discharge pattern is disturbed, resulting in a desired pattern. There was a problem that it was difficult to form.
JP 2003-135998 A

  The present invention has been made in view of the above points, and provides a method for manufacturing a coated plate that can easily form a desired pattern by reducing fluctuations in the discharge pattern of the paint by suppressing fluctuations in the discharge pressure of the paint. It is intended to do.

  The method for producing a coated plate of the present invention is a coated plate on which a coating film is formed by discharging a plurality of colors of paint 2 from one discharge port 45 of a coating gun 3 onto the surface of a continuously conveyed metal plate 1. In this manufacturing method, the paint 2 is supplied from the paint tank 4 to the paint gun 3 and discharged, and the paint 2 that is not discharged is returned to the paint tank 4.

  In the present invention, even when the paint 2 supplied to the painting gun 3 is not discharged, it can be distributed without staying in the painting gun 3, and the paint 2 accumulates pressure with the painting gun 3. As a result, the fluctuation of the discharge pressure of the paint 2 can be suppressed, the disturbance of the discharge pattern of the paint 2 can be reduced, and a desired pattern can be easily formed. is there.

  In the present invention, it is preferable that the paint is not discharged on the surface of the metal plate 1 for a predetermined time when the paint 2 to be discharged from the paint gun 3 is switched. In this case, when the paint 2 discharged from the paint gun 3 is switched to another paint 2, a predetermined time during which the paint 2 is not discharged is provided as a buffer time so that the paint 2 is discharged later onto the previously discharged paint 2. The pressure of 2 can be prevented from being affected, and the fluctuation of the discharge pressure of the paint 2 can be further suppressed.

  In the present invention, the painting gun 3 is installed in the painting booth 5 and painting can be performed while exhausting from below the painting booth 5. In this case, the paint 2 scattered by hitting the metal plate 1 can be exhausted from the inside of the painting booth 5 so that the scattered paint 2 is prevented from adhering to the metal plate 1 and the pattern is not soiled. Is something that can be done.

  In the present invention, a plurality of coating guns 3 are juxtaposed in a direction orthogonal to the conveying direction of the metal plate 1, and at least one of the coating guns 3 is transported in the metal plate 1 with respect to the other coating guns 3. It is preferable that they are arranged so as to be shifted in the front-rear direction along the line. In this case, it is possible to prevent the paint 2 discharged from the coating gun 3 disposed so as to be shifted in the front-rear direction and the paint 2 discharged from another adjacent coating gun 3 from interfering with each other. The contamination of the coating gun 3 can be reduced by reducing the amount.

  Further, in the present invention, it is preferable to paint while blowing air from the cover member 60 covering the periphery of the coating gun 3 toward the metal plate 1. In this case, the air blown out from the cover member 60 can prevent the paint 2 that hits the metal plate 1 from scattering toward the paint gun 3 and covers the periphery of the paint gun 3 with the cover member 60. By this, it is possible to prevent the scattered paint 2 from adhering to the coating gun 3, to prevent the paint gun 3 from being soiled by the adhered paint 2 and to the paint 2 adhering to the coating gun 3 from flowing down. It is also possible to prevent the metal plate 1 from being stained due to the above.

  In the present invention, it is preferable to discharge the paint 2 from the paint gun 3 inclined with respect to the surface of the metal plate 1. In this case, it is possible to reduce the amount of paint 2 supplied from the direction perpendicular to the surface of the metal plate 1, so that the impact of the paint 2 on the surface of the metal plate 1 is alleviated and the paint 2 hitting the metal plate 1 is scattered. Therefore, the contamination of the coating gun 3 due to the scattering of the paint 2 can be reduced.

  In the present invention, even if the paint supplied to the painting gun is not discharged, it can be distributed without staying in the painting gun, and the paint gun can be prevented from accumulating pressure. As a result, fluctuations in the discharge pressure of the paint can be suppressed, disturbances in the discharge pattern of the paint can be reduced, and a desired pattern can be easily formed.

  Hereinafter, the best mode for carrying out the present invention will be described.

  The method for producing a coated plate according to the present invention performs coating while continuously conveying a long metal plate 1 in the length direction. FIG. 2 shows a coating apparatus used in the present invention. In the figure, reference numeral 5 denotes a painting booth, and a painting gun 3 is provided at substantially the center inside the painting booth 5. In addition, an intake hole 20 is formed in the upper surface of the painting booth 5 and an exhaust duct 21 is disposed in the lower part of the painting booth 5. In addition, an inlet 22 is formed on one side of the painting booth 5 and an outlet 23 is formed on the other side facing the inlet 22.

  A back coater 24 is disposed in the vicinity of the inlet 22 of the painting booth 5. The back surface coater 24 includes a coater 25 for applying paint to the back surface of the metal plate 1, a tray 26 for receiving paint falling from the coater 25, driving means 27 such as a motor for rotating the coater 25, and the like. Is formed. A front surface coater 28 is disposed in the vicinity of the rear surface coater 24. The surface coater 28 includes a coater 29 for applying paint to the surface of the metal plate 1, a paint container 30 for storing paint, and a driving means 31 such as a motor for rotating the coater 29. Is formed. Further, a backup roll 32 is provided at a position facing the coater 29 and a plurality of transport rolls 33 for transporting the metal plate 1 are provided.

  FIG. 3 is a plan view of the coating apparatus. The exhaust duct 21 installed at the lower part of the painting booth 5 is connected to a dust collector 34. An operation panel 35 controls the operation of the painting apparatus. The painting apparatus is provided with three painting guns 3.

  FIG. 4 shows a schematic diagram of the painting booth 5. In the painting booth 5, three painting guns 3a, 3b, 3c are arranged horizontally in the direction orthogonal to the conveying direction of the metal plate 1 as the painting gun 3, but the painting gun 3b located in the middle of them is The other coating guns 3a and 3c on both sides are arranged so as to be shifted in the front-rear direction (parallel to the conveyance direction of the metal plate 1) along the conveyance direction of the metal plate 1. In the figure, the middle coating gun 3b is arranged upstream of the other coating guns 3a and 3c on both sides (the direction opposite to the conveying direction of the metal plate 1). You may arrange | position in the conveyance direction of the board 1). If it does in this way, the coating material 2 discharged from the coating gun 3b arrange | positioned shifted in the front-back direction along the conveyance direction of the metal plate 1 and the coating material 2 discharged from other adjacent coating guns 3a and 3c will collide. It is possible to prevent interference. That is, since the paint 2 discharged from the coating guns 3a to 3c spreads in a conical shape or an elliptical cone shape and is discharged, when the distance between the coating guns 3a to 3c is short, the coating guns 3a to 3c are discharged from the respective coating guns 3a to 3c. The paints 2 may collide and scatter, and the splattered paint 2 may adhere to and accumulate on the coating gun 3 and then fall onto the metal plate 1 and become dirty. Therefore, in the present invention, the coating guns 3a to 3c are arranged as described above to increase the distance between them, thereby reducing the collision of the paint 2 discharged from the coating guns 3a to 3c. It is possible to reduce the scattering of the paint 2 and prevent the pattern formed on the paint plate from becoming dirty. The paint gun 3b can be arranged 100 to 200 mm away from the line connecting the paint guns 3a and 3c, but this distance is appropriately set according to the discharge range of the paint 2 discharged from the paint guns 3a to 3c. Is possible. Further, with respect to the middle coating gun 3b, one of the coating guns 3a on both sides may be disposed on the upstream side and the other on the downstream side. Furthermore, as long as the paint 2 discharged from the coating guns 3a to 3c does not collide, the coating guns 3a to 3c may be arranged in a substantially straight line. Further, the number of paint guns 3 is not limited to three, and may be four or more.

  A paint pipe 34 is connected to each of the paint guns 3 a to 3 c, and a paint flow rate regulator 38 formed of an electromagnetic valve or the like is provided in the middle of the paint pipe 34. One end of the paint pipe 34 is connected to a paint supply machine 37 via a connector 36. The paint supply machine 37 is composed of three paint tanks 4a to 4c as paint tanks 4 and three pumps 39a to 39c provided corresponding to the paint tanks 4a to 4c. It is placed on the moving means 40 so as to be movable. One end of the paint pipe 34 is connected to pumps 39 a to 39 c of the paint supply machine 37. Further, a control air pipe 41 is connected to each of the coating guns 3a to 3c, and the control air pipe 41 is connected to an air switch 42 formed by a solenoid valve or the like. The air switch 42 is connected to an air generation source such as a compressor.

  FIG. 1 shows a schematic diagram of the paint pipe 34. The paint pipe 34 is composed of three supply pipes 35a to 35c and three return pipes 36a to 36c, and paint flow rate regulators 38a to 38c are provided in the middle of the supply pipes 35a to 35c. . The pumps 39a to 39c are connected to supply pipes 35a to 35c. One end of each of the three supply pipes 35a to 35c and the three return pipes 36a to 36c is connected to one coating gun 3. The other ends of the return pipes 36a to 36c are connected to the paint tanks 4a to 4c.

  FIG. 5 shows a schematic diagram of the control air pipe 41. Three control air pipes 41 are connected to one painting gun 3, and air switches 42a to 42c are provided in the control air pipes 41a to 41c. The air switches 42 a to 42 c are formed so as to be openable and closable by a control means 43 such as a sequencer operated by the operation panel 35. Each paint gun 3 is provided with three color selection valve portions 44a to 44c, and one color selection valve portion 44a is connected to a supply pipe 35a, a return pipe 36a and a control air pipe 41a one by one. The other color selection valve section 44b is connected with another supply pipe 35b, a return pipe 36b, and a control air pipe 41b one by one, and the other color selection valve section 44c is returned with another supply pipe 35c. One pipe 36c and one control air pipe 41c are connected.

  6 and 7 show an example of the coating gun 3 used in the present invention. The coating gun 3 is provided with color selection valve portions 44a to 44c protruding from the outer periphery of a gun body 46 provided with one discharge port 45 for the paint 2 on the front, and is supplied to each color selection valve portion 44a to 44c. A supply pipe connecting part 47 to which the pipes 35a to 35c are connected, a return pipe connecting part 48 to which the return pipes 36a to 36c are connected, and an air pipe connecting part 49 to which the control air pipes 41a to 41c are connected are provided. ing. Further, the gun main body 46 is connected to a pipe connecting portion 50 to which a pipe for supplying atomized air is connected and a pipe for supplying pattern air for changing the pattern of the paint 2 discharged from the coating gun 3. The piping connection part 51 to be performed is provided. As such a paint gun 3, a color combination gun “T2925” manufactured by Asahi Sunac Co., Ltd. can be used, but it is not limited to this. The coating gun 3 may be provided with a plurality of discharge ports 45.

  And when manufacturing a coating board using said coating apparatus, it carries out as follows. First, the long metal plate 1 is passed through the surface coater 28 while being conveyed (advanced) in the longitudinal direction. The metal plate 1 is conventionally used to form a building material, and examples thereof include a stainless steel plate, a galvanized steel plate, and an aluminum-galvanized steel plate (galvalume steel plate), but are not limited thereto. Is not to be done. The metal plate 1 may have an undercoat coating (primer coating) formed on the surface thereof.

  The base coating 52 is applied by the coater 29 on the entire surface of the metal plate 1 conveyed as described above (the entire surface of the undercoat if there is an undercoat) when passing through the surface coater 28. The base paint 52 has been conventionally used for building materials and is applied to give the metal plate 1 performance such as corrosion resistance, weather resistance, and wear resistance. As such a base paint 52, a polyester resin paint, a urethane resin paint, a vinylidene fluoride resin paint, an acrylic resin paint, a polyolefin resin paint or the like can be used alone or in admixture of two or more. In addition, a pigment is blended in the base paint 52, whereby the base paint 52 is colored in a desired color. Examples of the pigment include various color pigments, rust preventive pigments, extender pigments (silica, alumina, calcium carbonate, barium sulfate, kaolin clay, etc.), but are not limited thereto. The pigment can be blended in consideration of colorability, improvement in adhesion to the resin in the paint, concealment of the base, and the like. Furthermore, as the base paint 52, for example, a shrink paint (a paint having a shrinking property and having a matting effect) as disclosed in JP-A-2002-146280 can be used.

  The base paint 52 can be blended with an aggregate as a matting agent, an anti-scratch agent, or for the purpose of improving adhesion (anchor effect). Examples of the aggregate include glass fibers, glass beads, resin beads, mica, and the like, but are not limited thereto. Further, the base paint 52 is blended with a thickener such as synthetic fine silica, organic bentonite, carboxymethylcellulose, polyvinyl alcohol, a crosslinking agent such as melamine, benzoguanamine, or isocyanate, or a dispersant such as polyacrylic acid. Also good. In the present invention, the viscosity of the base paint 52 is, for example, Ford Cup No. Although it is preferable to set it as 30 to 120 second by the measurement by 4 methods, it is not limited to this.

  After applying the base paint 52 as described above, the metal plate 1 is conveyed to the back surface coater 24, and the paint is applied by the coater 25 when passing through the back surface coater 24. This paint is conventionally used for building materials and the like, and is applied to the metal plate 1 in order to impart performance such as corrosion resistance, weather resistance, and wear resistance, and is similar to the base paint 52 described above. Can be used.

  After applying the paint on the back surface of the metal plate 1 as described above, the metal plate 1 is introduced into the painting booth 5 from the introduction port 22. When passing under the plurality of coating guns 3, a plurality of paints 2 having different colors are applied. As the finishing paint 2, the same paint as the base paint 52 can be used. That is, as the paint 2, as described above, various resin paints such as a polyester resin paint, which are blended with pigments, aggregates, and other components can be used. Further, as the paint 2, a plurality of colors of paints 2a, 2b, and 2c having different colors are used. Here, although the case where three types of paints 2a to 2c having different colors are used will be described, the present invention is not limited to this, and two types of paints 2 having different colors or four or more types may be used. Of the multiple-color paints 2a to 2c having different colors, one kind of paint 2a is prepared in the same color as the base paint 52, and the other finish paints 2b and 2c are prepared in different colors from the base paint 52. Yes. In this case, the paint 2a having the same color as the base paint 52 is colored using the same pigment as the base paint 52, and the finish paints 2b and 2c having different colors are colored using a pigment different from the base paint 52. Can do. The finish paint 2a having the same color as that of the base paint 52 is preferably prepared by diluting the base paint 52 with an appropriate colorless solvent, whereby the paint 2a having the same color as that of the base paint 52 is obtained using the base paint 52. Compared with the case where the base paint 52 and the paint 2a are prepared separately, the labor can be reduced and the color difference between the base paint 52 and the finish paint 3a is less likely to occur. It will be. As will be described later, since the base paint 52 is applied by a roll coater and the paint 2a is applied by a spray gun, the base paint 52 is used as it is to reduce the viscosity by diluting the paint 2a. Is preferred. In the present invention, the viscosity of the finish paint 3 is, for example, Ford Cup No. Although it is preferable to set it as 15 to 45 seconds by the measurement by 4 methods (JIS K 5400), it is not limited to this.

  Thereafter, the metal plate 1 is led out from the coating booth 5 through the outlet 23 and then introduced into the baking furnace 54. Then, a base plate 52 coated on the metal plate 1 in the baking furnace 54, the back surface coating, and the finishing coatings 2a to 2c painted with the coating gun 3 are cured and baked to produce a coated plate having a pattern. Can do. In addition, although it is preferable that the coating films of the base paint 52 and the finishing paint 2 formed on the metal plate 1 are 10 to 50 μm, the present invention is not limited to this. Moreover, the spray conditions of the coating material 2 for finishing are the atomization pressure of 0.1 to 0.3 MPa, the pattern pressure of 0.1 to 0.3 MPa, the discharge amount of 100 to 500 ml / min, and the discharge time of the coating material of 0.1. The non-ejection time of the coating material 2 may be 0.01 to 0.2 seconds, but is not limited thereto. Further, the line speed (conveying speed of the metal plate 1) can be 30 to 120 m / min, the baking temperature in the baking furnace 54 can be 180 to 250 ° C., the baking time 20 to 100 seconds, but is not limited thereto. It is not something.

  The spray coating with the coating gun 3 is performed as follows. First, during operation of the coating apparatus, the paints 2a to 2c are constantly circulated between the color selection valve portions 44a to 44c of the paint guns 3a to 3c and the paint tanks 4a to 4c. That is, by the action of the pumps 39a to 39c, the paints 2a to 2c are supplied from the paint tanks 4a to 4c through the supply pipes 35a to 35c to the color selection valve parts 44a to 44c and supplied to the color selection valve parts 44a to 44c. The operation of passing 2a-2c as it is and returning it to the paint tanks 4a-4c through the return pipes 36a-36c is always performed during operation of the coating apparatus.

  When discharging any one of the paints 2a to 2c from one paint gun 3, air is supplied to one of the color selection valve portions 44a to 44c through which the paint 2 to be discharged is distributed. It supplies through 41a-41c. For example, when the paint 2a is discharged from the paint gun 3a, air is supplied to the color selection valve portion 44a of the paint gun 3a through the control air pipe 41a. As a result, the target paint 2a is introduced into the gun body 46, and then is discharged from the discharge port 45 by the action of atomizing air or pattern air and applied to the metal plate 1 (the surface of the base paint 52). Similarly, by sequentially switching the color selection valve portions 44a to 44c for supplying air by the control means 43, it is possible to sequentially discharge a plurality of paints 2a to 2c having different colors from one coating gun 3. By controlling the coating guns 3a to 3c by the control means 43, a plurality of paints 2a to 2c having the same color or different colors can be applied at the same time, and a pattern can be formed with a paint film by painting.

  In the present invention, it is possible to apply a plurality of colors of paint 2 with a single paint gun 3, and it is not necessary to provide a paint gun 3 for each color of the paint. Therefore, the coating apparatus can be made compact and as a whole. Cost can be reduced. In addition, even when the paints 2a to 2c supplied to the color selection valve portions 44a to 44c of the coating gun 3 are not discharged as described above, the color selection valve portions 44a to 44c of the coating gun 3 remain. The paint 2a to 2c can be prevented from accumulating at the color selection valve portions 44a to 44c of the coating gun 3. Therefore, fluctuations in the discharge pressure of the paints 2a to 2c can be suppressed, and disturbances in the discharge patterns of the paints 2a to 2c can be reduced.

  Further, it is preferable to provide a non-ejection time during which neither paint 2 is ejected from the paint gun 3 when the paint 2a ejected from one paint gun 3 is switched to another color paint 2b, 2c. Thus, when switching the paint 2a discharged from the paint gun 3 to the other paints 2b and 2c, the non-discharge time in which the discharge of any paint 2 is stopped is provided as a buffering time, thereby discharging the paint 2a first. It is possible to prevent the pressure of the paints 2b and 2c discharged later from affecting the paint 2a.

  Further, the above-described coating apparatus operates the dust collector 34 and paints with the coating gun 3 while exhausting from the painting booth 5 through the exhaust duct 21. Accordingly, air is supplied into the painting booth 5 from the intake hole 20 on the upper surface, and the paint 2 scattered in the painting booth 5 can be sucked into the exhaust duct 21 and scattered by hitting the metal plate 1 or the like. The applied paint (paint mist) 2 can be exhausted from the inside of the painting booth 5, and the scattered paint 2 can be prevented from adhering to the metal plate 1, the painting gun 3, and the like. In particular, since the exhaust duct 21 is provided below the painting booth 5 (below the metal plate 1 being conveyed), the air flow in the painting booth 5 is from the top to the bottom, and the exhaust duct 21 is connected to the painting booth. The effect of preventing the paint 2 from scattering is higher than that provided on the side (side surface) of 5. Although the wind speed in the painting booth 5 produced by the exhaust by the exhaust duct 21 can be 1 to 5 m / sec, it is not limited to this.

  In the present invention, as a measure for preventing contamination of the coating gun 3, it is preferable to cover each coating gun 3 with a cover member 60 as shown in FIG. The cover member 60 is formed in a cylindrical shape having an open bottom surface, and an air supply unit 61 is provided on the upper portion thereof. The cross-sectional shape of the cover member 60 may be an arbitrary shape such as a circle or a rectangle. The coating gun 3 is disposed inside the cover member 60, but the lower portion of the coating gun 3 provided with the discharge port 45 for the paint 2 protrudes from the lower surface opening of the cover member 60. Further, a shielding plate 63 is projected around the lower part of the coating gun 3. The shielding plate 63 is formed by using a filter or the like formed of a breathable material such as a nonwoven fabric, and the lower portion of the coating gun 3 is covered by the shielding plate 63. Further, the paint pipe 34, the control air pipe 41, etc. pass through the upper part of the cover member 60 and are introduced inside to be connected to the paint gun 3.

  In the case of using the coating gun 3 covered with the cover member 60 in this way, in the same manner as described above, the long metal plate 1 coated with the base paint is passed under the coating gun 3 while being transported horizontally. Occasionally, paint 2 is ejected (discharged) from the discharge port 45 of the coating gun 3 to apply the coating to the metal plate 1, while the coating gun 3 discharges the coating 2 toward the metal plate 1 from the cover member 60. To blow out air. That is, air is supplied to the inside of the cover member 60 through the air supply unit 61 and this air is circulated through the flow path 64 between the coating gun 3 and the inner surface of the cover member 60, and thereafter, as indicated by an arrow a. Then, air is blown out from the lower surface opening of the cover member 60 (down flow). And by blowing out air from the lower surface of the cover member 60 in this way, the paint 2 blown out from the coating gun 3 hits the surface of the metal plate 1 and bounces back toward the coating gun 3 as shown by arrow B. Further, by covering the periphery of the coating gun 3 with the cover member 60, it is possible to prevent the scattered paint 2 from adhering to the coating gun 3. Accordingly, it is possible to prevent the paint gun 3 from being smeared by the scattered paint 2 and to prevent the metal plate 1 from being smeared by the paint 2 adhering to the paint gun 3 (dropping). Further, the air from the cover member 60 is blown out through the shielding plate 63 and is subjected to a rectifying action, so that the air flow can be prevented from becoming uneven. Further, the shielding plate 63 can prevent the scattered paint 2 from adhering to the lower part of the coating gun 3. In addition, although the blowing of the air from the cover member 60 can be made into the wind speed of 0.5-5 m / sec, Preferably it is 1-2 m / sec, It is not limited to this.

  The cover member 60 can be formed of a metal plate such as a stainless steel plate, but a punching metal (perforated plate) may be used as the metal plate. In this case, the cover member 60 may be formed on the outer surface (side wall) of the cover member 60. Can be provided with a filter similar to the above. When the cover member 60 is formed using a punching metal, the air flowing through the flow path 64 leaks from the hole, and the paint 2 scattered on the outer surface of the cover member 60 adheres due to the leaked air. Therefore, it is possible to prevent the cover member 60 from being contaminated by the scattered paint 2.

  When such anti-smudge measures are taken for the paint gun 3, even if the paint conditions are such that the paint gun 3 becomes smeared after 30 to 40 minutes before the measure is taken, even after 120 minutes have passed, the paint gun 3 was not contaminated.

  FIG. 9 shows another example of measures for preventing the paint gun 3 from being stained. In this example, the paint 2 is discharged from a paint gun 3 inclined with respect to the surface of the metal plate 1. That is, the perpendicular L1 with respect to the surface of the metal plate 1 and the axis L2 connecting the center of the coating gun 3 and the discharge port 45 are not parallel, and a certain angle is formed between the perpendicular L1 and the axis L2. In addition, the coating gun 3 is inclined and arranged.

  Even when such a coating gun 3 is used, the discharge port of the coating gun 3 is used when the long metal plate 1 coated with the base paint is passed under the coating gun 3 while being transported horizontally in the same manner as described above. The metal plate 1 is coated by spraying (discharging) the paint 2 from 45. When the coating gun 3 is arranged perpendicularly to the surface of the metal plate 1 with the perpendicular line L1 and the axis L2 being parallel, the paint 2 discharged from the coating gun 3 has a component that hits the surface of the metal plate 1 perpendicularly. For this reason, the impact of the coating material 2 hitting the surface of the metal plate 1 is the largest, so that the amount of the coating material 2 scattered as the coating mist tends to increase. Therefore, by disposing the coating gun 3 at an angle, the component 2 that is perpendicular to the surface of the metal plate 1 in the paint 2 discharged from the coating gun 3 is reduced, and the metal plate as shown by the arrow C in FIG. The mist-like (mist) paint 2 is poured along the surface of the paint 1 to alleviate the impact of the paint 2 hitting the surface of the metal plate 1. The amount can be reduced. Accordingly, it is possible to reduce the contamination of the coating gun 3 with the scattered paint 2.

  If the inclination of the coating gun 3, that is, the angle between the perpendicular line L1 and the axis L2, is too small, the impact mitigating effect of the paint 2 is small, and if it is too large, the discharge (spray) of the paint 2 is biased and the coating is uniform. Is damaged. Therefore, the appropriate angle α between the perpendicular line L1 and the axis line L2 is preferably 10 to 30 °.

  Hereinafter, the present invention will be described specifically by way of examples.

  The coating board was manufactured using the coating apparatus shown in FIGS. As the metal plate 1, a long steel plate having a width of 914 mm and a thickness of 0.35 mm was used.

  As the base paint 52, a polyester resin paint (“S03-G4651” manufactured by NOF BASF Coatings Co., Ltd.) and a pigment colored with a light orange hue was used. The viscosity (20 ° C.) of the base paint 52 is a Ford Cup No. Viscosity measurement using 4 was 60 seconds.

  As the finishing paint 2a having the same color as the base paint 52, a base paint 52 diluted with a solvent containing cyclohexanone and solvent naphtha as main components was used. The viscosity (20 ° C.) of this paint 2a is the Ford Cup No. The viscosity measurement using 4 was 30 seconds.

  As the base paint 52 and the finishing paint 2b having a different color, a pigment is blended with the same polyester resin paint as described above to give a dark orange hue. Further, by blending the same solvent as described above, the viscosity (20 ° C.) of the paint 2b was changed to Ford Cup No. Viscosity measurement using 4 was 30 seconds.

  As the base paint 52 and the finishing paint 2c having a different color, a beige hue is prepared by blending a pigment in the same polyester resin paint as described above. Further, by blending the same solvent as described above, the viscosity (20 ° C.) of the paint 2c was changed to Ford Cup No. Viscosity measurement using 3 was 30 seconds.

  Then, the base coating 52 and the finishing coatings 2a to 2c were applied while conveying the metal plate 1 at a line speed of 65 m / min. Here, the spraying conditions were an atomization pressure of 0.20 MPa, a pattern pressure of 0.17 MPa, and a discharge amount of 290 ml / min (each color). Also, the spray pattern by the coating gun 3 is that the paint 2a is discharged for 0.15 seconds → no discharge for 0.10 seconds → the paint 2b is discharged for 0.20 seconds → no discharge for 0.10 seconds → the paint 2c is 0.20. Discharge for seconds → No discharge for 0.08 seconds → Paint 2a was discharged for 0.15 seconds →. FIG. 10 shows a repeating pattern of discharge (ON) and non-discharge (OFF) of the paints 2a to 2c. In this way, the paint 2a having the same color as the base paint 52 and the paints 2b and 2c having different colors partially overlap (20% in terms of area). As the coating gun 3, a color combination gun “T2925” manufactured by Asahi Sunac as shown in FIGS. Moreover, it exhausted through the exhaust duct 21 so that the wind speed in the painting booth 5 might be set to 1 m / sec. Next, the metal plate 1 after spray coating is introduced into a baking furnace 54 and baked at a temperature of 230 ° C. for 50 seconds, whereby the coating thickness of the base coating 52 is 18 μm and the coatings of the finishing coatings 2a to 2c. A coated plate having a thickness of 5 to 10 μm was obtained. Thereafter, the coated plate was bent by roll molding or the like and cut to a predetermined length to form a horizontal roofing material. This horizontal roofing material had a pattern in which the color tone gradually changed.

It is the schematic which shows an example of embodiment of this invention. It is a schematic diagram same as the above. It is the schematic of planar view same as the above. The state of the piping of the same paint is shown, and (a) and (b) are schematic views. It is the schematic which shows the state of piping of the air same as the above. It is a front view which shows an example of the same painting gun. It is sectional drawing which shows an example of a coating gun same as the above. It is the schematic which shows an example of the dirt prevention countermeasure of a coating gun same as the above. It is the schematic which shows the other example of the stain | pollution | contamination prevention measure of a coating gun same as the above. It is explanatory drawing which shows a spray pattern same as the above.

Explanation of symbols

1 Metal Plate 2 Paint 3 Paint Gun 4 Paint Tank 5 Paint Booth 45 Discharge Port 60 Cover Member

Claims (6)

  Supplying paint from the paint tank to the paint gun in a method for producing a paint film by discharging multiple colors of paint on the surface of a continuously conveyed metal plate while switching from one discharge port of the paint gun. Then, the paint that is discharged and discharged is returned to the paint tank.   2. The method for manufacturing a coated plate according to claim 1, wherein when the coating material discharged from the coating gun is switched, the coating material is not discharged onto the surface of the metal plate for a predetermined time.   The method for producing a coated plate according to claim 1 or 2, wherein a painting gun is installed in the painting booth, and painting is performed while exhausting from below the painting booth.   A plurality of coating guns are juxtaposed in a direction perpendicular to the conveying direction of the metal plate, and at least one of the coating guns is arranged shifted in the front-rear direction along the conveying direction of the metal plate with respect to the other coating guns. The method for producing a coated plate according to any one of claims 1 to 3.   The method for manufacturing a coated plate according to any one of claims 1 to 4, wherein the coating is performed while blowing air from a cover member covering the periphery of the coating gun toward the metal plate.   6. The method for producing a coated plate according to claim 1, wherein the coating material is discharged from a coating gun inclined with respect to the surface of the metal plate.

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