JP2010234186A - Method of coating automotive body and device using this method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively inhibit, under a simple construction, the undermining of a presentable outlook which is attributable to the deposition of coating material dust on the coating of an inner plate surface when the coating material is applied to the outer plate surface of an automotive body. <P>SOLUTION: This method of coating the automotive body comprises a first coat forming process K1 to form a first coat 5 which develops an outlook coating color, by applying a first coating material to an inner plate surface 3 of an automotive body 1, a second coat forming process K2 to form a second coat 6 with undercoat concealability by applying a second coating material to an outer plate surface 2, and a third coat forming process K3 to form a third coat 7 which develops, alone or together with the second coat 6, an outlook coating color of the same kind as or an approximate kind to the first coat 5 and has lower undercoat concealability than the second coat 6, through the procedures to apply a third coating material to the surface of the second coat 6 after the formation of the latter 6. Besides, in the third coat forming process K3, the behavior of the third coating material to wrap around to the inner plate surface 3 side of the automotive body, when applying the third coating material to the outer plate surface 2, is promoted. Also, the device using this method is provided. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a method and apparatus for coating an automobile body, in which a paint is applied to an outer plate surface and an inner plate surface of an automobile body on which a base coating film is formed.

  Conventionally, as shown in Patent Document 1 below, chipping resistance and smoothness of a multi-layer top coating film formed by sequentially applying a first colored top coating, a second colored top coating, and a clear coating to be formed on an electrodeposition coating surface For the purpose of improving the property, an automobile outer plate portion or the like that forms a multi-layer top coat film by sequentially applying a first colored top coat paint, a second colored top coat paint and a clear paint on the cationic electrodeposition coated surface, etc. In the method for coating a conductive metal product, the first colored top coating composition comprises, as a resin component, (1) a mixture comprising a hydroxyl group-containing resin and a melamine resin, or (2) a carboxyl group-containing resin and an epoxy group-containing resin. There is known a mixture using a colored paint containing a flake pigment at a ratio of 0.5 parts by weight or more per 100 parts by weight of resin solids.

JP 2000-281963 A

  As described above, the first colored top coating, the second colored top coating, and the clear coating are sequentially applied to the cationic electrodeposition coating surface, and then cured simultaneously to form a multi-layer top coating film. In the method for forming a layer coating film, by adding a specific amount of flake pigment to the first colored top coating material, the smoothness and anti-resistance property of the coating film can be eliminated even if the conventional intermediate coating method or the drying step is omitted. Chipping property can be improved. However, if the coating of the intermediate coating is omitted as described above, the ultraviolet blocking function and the like that the intermediate coating has had cannot be obtained. For this reason, when the top coat is a paint having a weak UV blocking function, such as a blue, white or red paint, an ultraviolet ray is applied to the undercoat made of an electrodeposition paint formed on the outer surface of the vehicle body. However, it is unavoidable that the undercoating film is easily deteriorated at an early stage.

  In order to prevent the above-mentioned adverse effects, it is conceivable to conceal and protect the undercoat by mixing a pigment having a function of reflecting or absorbing ultraviolet rays or the like into the first colored top coat. In this case, the pigment mixed in the first colored top coat may adversely affect the paint applied on the inner plate surface of the vehicle body. That is, since the coating film made of the second colored top coating applied on the outer surface of the vehicle body develops the color of the exterior coating film of the vehicle body, it is selected from a wide variety of colors used in advance. In addition, the coating film made of the top coating applied on the inner plate surface may be the same color or approximate color as the coating made of the second colored top coating applied on the outer plate surface from the viewpoint of aesthetics. It is common. On the other hand, the first colored top coating applied below the coating formed by the second colored top coating is, as long as the upper coating can develop a desired appearance coating color, The color can be an achromatic color, whereby the first colored top coat can be made versatile. However, in such a configuration, when the first colored top coat is applied on the outer plate surface of the vehicle body, if the dust adheres to the upper coat film on the inner plate surface, the aesthetics on the inner plate surface is improved. There is a problem of lowering.

  The color of the coating formed by the first colored top coating is changed from the coating of the second colored top coating that develops the appearance coating color and the third colored top coating applied to the inner plate surface. When the coating film is set to the same color or an approximate color, the appearance of the coating film on the inner plate surface is significantly reduced even if the dust of the first colored top coating material adheres to the upper coating film on the inner plate surface Never do. However, in order to set the coating film made of the first colored top coating material mixed with the pigment having the background concealing property as described above to various colors corresponding to the appearance coating film color, It is inevitable that the workability of painting is deteriorated because it is necessary to prepare a large number of pipes required for painting the colored top coat and frequently replace them.

  The present invention has been made in view of the above problems, and is caused by the fact that the dust of the paint applied on the outer plate surface of the automobile body with a simple configuration adheres to the coating film on the inner plate surface. It is an object of the present invention to provide a method and apparatus for painting an automobile body that can effectively prevent a decrease in aesthetic appearance.

  The invention according to claim 1 is a first coating film forming step of forming a first coating film for coloring the appearance coating film color by applying the first coating material on the inner plate surface of the automobile body on which the base coating film is formed. And a second coating film forming step of forming a second coating film having a base concealing property by applying a second coating material on the outer plate surface of the automobile body, and after forming the second coating film, Applying three paints, the underlying coating is less concealed than the second coating film, and the third coating film alone or together with the second coating film has the same or similar appearance coating color as the first coating film. And a third coating film forming step for forming a third coating film, wherein the third coating material is applied to the outer plate surface in the third coating film forming step. 3 It is configured so as to promote the coating material wrapping around the inner plate surface side of the automobile body.

  Here, the base concealing property means that the transmittance of ultraviolet light (300 to 400 nm) is 0.05% or less and the black and white concealing property in the case of a coating color with a lightness ≦ 60 (illumination angle −45 °, light receiving angle 0 °). Can be ensured at 10 μm or less, and the transmittance of ultraviolet light (300 to 400 nm) is 0.05% or less when the coating color (lighting angle −45 °, light receiving angle 0 °) with lightness> 60 is black and white. This means that the concealability can be secured at 20 μm or less (see JIS K 5400 · 7.2 (2) f).

  The approximate color means a color difference ≦ 2 (illumination angle −45 °, light receiving angle 0 °) (see JIS Z 8730).

  According to a second aspect of the present invention, in the method of coating an automobile body according to the first aspect, the spray pattern of the third paint sprayed on the outer plate surface of the automobile body in the third coating film forming step is shaving air. It is configured to be adjusted according to the flow velocity of the car body, and at the place where the paint sprayed toward the outer plate surface of the automobile body may go around to the inner plate surface side, the flow velocity of the shaving air is changed to other portions. In this case, the third paint is made to rise more than when the third paint is sprayed, so that the third paint wraps around the inner plate surface of the automobile body.

  According to a third aspect of the present invention, in the method for coating an automobile body according to the first aspect, in the third coating film forming step, the third body is applied by charging the automobile body and the electrostatic coating machine to opposite electrodes. It is configured to spray on the outer plate surface of the automobile body, and in places where the paint sprayed toward the outer plate surface of the automobile body may go around to the inner plate surface side, the third paint and the outside of the automobile body By making the potential difference with the plate surface narrower than when the third paint is sprayed on other portions, the third paint wraps around the inner plate surface side of the automobile body.

  According to a fourth aspect of the present invention, in the method for coating an automobile body according to the first aspect, the opening is formed on the outer plate surface, and the opening / closing body for opening and closing the opening is provided at the site. By opening the opening / closing body and increasing the opening area of the opening, the third paint is circulated toward the inner plate surface side of the automobile body.

  According to a fifth aspect of the present invention, there is provided a method for painting an automobile body according to the first aspect, wherein the third coating film forming step is configured to adjust the spray direction of the paint on the outer plate surface of the automobile body. It is configured to spray the third paint using an electropainting machine, and in places where the paint sprayed on the outer plate surface of the car body may go around to the inner plate surface side, the outer plate surface of the car body By adjusting the spray direction of the electrostatic coating machine so that the third paint sprayed toward the inner surface is concentrated on the inner plate surface side, the third paint wraps around the inner plate surface side of the automobile body. It is comprised as follows.

  The invention according to claim 6 is the method for coating an automobile body according to any one of claims 1 to 5, wherein the second coating having a lightness lower than that of the third coating is formed in the second coating film forming step. The film is formed on the outer plate surface of the automobile body.

  The invention according to claim 7 is the automobile body coating method according to any one of claims 1 to 6, wherein at least after the first coating film forming step, a clear coating film is formed on the inner plate surface of the automobile body. An inner plate clear coating film forming step is provided.

  The invention according to claim 8 is the automobile body coating method according to any one of claims 1 to 7, wherein at least after the third paint film forming step, a clear paint film is applied to the outer plate surface of the car body. The outer plate clear coating film forming step is formed.

  The invention according to claim 9 is a first coating film forming portion that forms a first coating film that develops an appearance coating film color by applying a first coating material on an inner plate surface of an automobile body on which a base coating film is formed. And a second coating film forming portion for forming a second coating film having a base concealing property by applying a second coating material on the outer plate surface of the automobile body, and after forming the second coating film, Applying three paints, the underlying coating is less concealed than the second coating film, and the third coating film alone or together with the second coating film has the same or similar appearance coating color as the first coating film. An automobile body coating apparatus including a third coating film forming unit for forming a third coating film, wherein the third coating material is applied to the outer plate surface of the automobile body by the third coating film forming unit. The third paint is provided with an accelerating means for accelerating the wrapping around the inner plate surface side.

  The invention according to claim 10 is the automobile body coating method according to claim 9, further comprising an inner plate clear coating film forming portion for forming a clear coating film on the first coating film of the inner plate surface. Is.

  According to an eleventh aspect of the present invention, in the automobile body coating apparatus according to the ninth or tenth aspect, an outer plate clear coating film forming portion for forming a clear coating film on the third coating film of the outer plate surface is provided. It is provided.

  In the invention according to claim 1 and claim 9, when the third coating material is applied to the outer plate surface of the automobile body in the third coating film forming step, the third coating material wraps around the inner plate surface side. Since the dust of the second paint sprayed in the second paint film forming step adheres to the inner plate surface, the dust paint film formed by the first paint is formed. An inner plate formed by exposing the dust coating formed by the second coating by covering with the third coating formed by the third coating that develops the same or approximate appearance coating color as the coating It is possible to prevent a decrease in the aesthetic appearance of the surface. Therefore, it is possible to make the second coating material for the second coating film versatile by setting the color of the second coating film to an achromatic color or the like, and it is necessary to apply the second coating material. It is possible to effectively simplify the coating apparatus by reducing the number of pipes, and to mix the pigment for concealing the base into the second paint forming the second coating film, or to reduce the content of the colored pigment in the second paint. By setting more than, the base concealment property which the said 2nd coating film has can be improved effectively. For this reason, the work of painting and drying the intermediate coating on the base coating film formed on the outer plate surface of the automobile body is omitted, simplifying the painting process, and the visible surface irradiated with the outer plate surface. Light or ultraviolet rays can be reflected or absorbed by the carbon black or coloring pigment blended in the second coating film, so that it is possible to suppress the arrival of ultraviolet rays etc. in the base coating film. There is an advantage that deterioration can be effectively prevented.

  In the invention according to claim 2, the flow rate of the shaving air is a place where the third paint sprayed toward the outer plate surface of the automobile body in the third coating film forming step may go around to the inner plate surface side. Is increased compared with the case where the third paint is sprayed on other portions, so that the third paint wraps around the inner plate surface side can be effectively promoted with a simple configuration. There is an advantage that the dust coating film of the second paint formed on the plate surface can be efficiently concealed.

  In the invention according to claim 3, the potential difference between the third paint and the outer plate surface of the automobile body is determined at a portion where the paint sprayed toward the outer plate surface of the automobile body may go around to the inner plate surface side. The amount of the third coating adsorbed on the outer plate surface is reduced by narrowing the third coating compared to the case where the third coating is sprayed on other portions, and the third coating wrapping around to the inner plate surface side correspondingly is reduced. Since the amount of the dust coating can be increased, the dust coating of the second coating sprayed in the second coating forming step adheres to the inner plate surface. By covering the formation range with the dust coating of the third paint that produces the same or approximate appearance paint color as the first paint, the dust coating of the second paint is effectively prevented from being exposed. There is an advantage that you can.

  In the invention which concerns on Claim 4, when spraying a 3rd coating material in the said 3rd coating-film formation process at the site | part in which the opening part was formed in the outer-plate surface and the opening-closing body which opens and closes the said opening part was provided The flow angle of the third paint passing through the opening is reduced by a very simple operation of increasing the opening angle of the opening / closing body slightly from the normal time, and the third paint wraps around the inner plate surface side. Therefore, even if the dust coating film is formed by the dust of the second paint sprayed in the second coating film forming step adhering to the inner plate surface, the formation range of the dust coating film is reduced. The advantage that the dust coating film of the second paint can be effectively prevented from being exposed by covering it with the dust coating film of the third paint that develops the same or approximate appearance paint color as the first paint. There is.

  In the invention which concerns on Claim 5, the 3rd coating material sprayed on the outer-plate surface of the motor vehicle body by the electrostatic coating machine comprised so that adjustment of the spraying direction of the 3rd coating material was possible at the said 3rd coating-film formation process is an inner plate. By adjusting the spray direction so that the third paint sprayed toward the outer plate surface of the automobile body is concentrated on the opening at the portion where there is a possibility of wrapping around the surface side, the third paint toward the inner plate surface side is adjusted. Since the configuration is such that the wraparound of the three paints is promoted, there is an advantage that it is possible to easily and effectively prevent a decrease in aesthetics caused by the exposure of the dust coating film of the second paint.

  In the invention which concerns on Claim 6, the brightness of the 2nd coating film formed in the outer-plate surface of a motor vehicle body in a 2nd coating-film formation process by setting more content of the color pigment with respect to a 2nd coating than usual etc. However, since it was configured to be lower than the third coating film formed on the outer plate surface of the automobile body in the third coating film forming step, it was caused by the fact that the base coating film was irradiated with ultraviolet rays with a simple configuration, etc. There is an advantage that early deterioration of the base coating film can be effectively suppressed.

  In the inventions according to claims 7 and 10, since the clear coating film is formed on the first coating film formed on the inner plate surface of the automobile body, the second and third coating films are formed. Even when the dust coating film formed by adhering the second and third paints sprayed in the forming process is formed on the first coating film on the inner plate surface, the first coating film is covered with the clear coating film. Thus, there is an advantage that the smoothness and weather resistance can be effectively maintained.

  In the inventions according to claims 8 and 11, since the clear coating film is formed on the third coating film formed on the outer plate surface of the automobile body, the third coating film is formed by the clear coating film. The smoothness and weather resistance can be effectively maintained by coating the coating film, and the dust of the clear paint sprayed toward the inner plate surface adheres to the third coating film on the outer plate surface. Even in this case, the smoothness of the outer plate surface can be sufficiently ensured.

It is process drawing which shows 1st Embodiment of the coating method of the motor vehicle body which concerns on this invention. It is explanatory drawing which shows the spraying state of a 3rd coating material. It is explanatory drawing which shows the coating-film shape formed by the coating method of this invention. It is explanatory drawing which shows the reflective state of the light of the coating film formed by the coating method of this invention. It is explanatory drawing which shows 2nd Embodiment of the coating method of the motor vehicle body which concerns on this invention. It is explanatory drawing which shows 3rd Embodiment of the coating method of the motor vehicle body which concerns on this invention. It is explanatory drawing which shows 4th Embodiment of the coating method of the motor vehicle body which concerns on this invention.

  FIG. 1 is a painting process diagram showing a first embodiment of a method and apparatus for painting an automobile body 1 according to the present invention. This coating process includes a base coating film forming process K0 for forming the base coating film 4 on the outer plate surface 2 and the inner plate surface 3 of the automobile body 1, and a first coating on the base coating film 4 on the inner plate surface 3, respectively. First coating film forming step K1 for forming film 5, second coating film forming step K2 for forming second coating film 6 on base coating film 4 on outer plate surface 2, and second coating on outer plate surface 2 A third coating film forming step K3 for forming a third coating film 7 on the film 6, a preheating step K4 for pre-drying the first to third coating films 5 to 7, and a first coating of the inner plate surface 3; An inner plate clear coating film forming step K5 for forming a clear coating film 8 on the film 5, and an outer plate clear coating film forming step K6 for forming a clear coating film 9 on the third coating film 7 on the outer plate surface 2; And a baking drying step K7 for baking and drying the first to third coating films 5 to 7 and the clear coating films 8 and 9 at the same time.

  In the base coating film forming step K0, for example, the automobile body 1 is pulled up from the tank after being applied with a direct current by applying a direct current in a state where the automobile body 1 is immersed in a tank containing an electrodeposition paint. Is transferred into a drying furnace and baked and dried to form a base coating film 4 having an antirust function of the automobile body 1. The electrodeposition coating method includes an anion form using chromate or the like as a rust preventive material and a cation form using a modified epoxy resin or the like excellent in rust preventive power with an amine.

  In the first coating film forming step K1, in the first coating film forming section 12 having the electrostatic coating machine 11 or the like, the outside of the automobile body 1 is opened with the opening / closing body 13 composed of a side door or the like of the automobile being largely opened. By spray-coating the first paint on the plate surface 2, the first coating film 5 that develops the appearance paint film color is formed on the base coating film 4 on the inner plate surface 3. The first paint is a water-soluble paint obtained by dissolving or dispersing a coloring pigment for coloring the appearance paint film color of the inner plate surface 3 and a resin component in a solvent made of water. Depending on the conditions, extender pigments, anti-settling agents, coating surface conditioners, UV absorbers, UV stabilizers, adhesion-imparting agents and the like can be appropriately contained.

  The spray coating of the first paint using the electrostatic coating machine 11 is performed using, for example, an object to be coated made of an automobile body 1 as an anode (+) and an electrostatic coating machine 11 as a cathode (−). In a state where a high voltage of several tens of kV is applied to form a static electric field, the paint particles are charged on the cathode (−) and sprayed, whereby the paint particles are coated with electrostatic attraction (automobile body 1). It is made to adsorb to. The spray pattern of the paint sprayed from the electrostatic coating machine 11 is adjusted according to the flow rate of the shaving air blown out from the spray gun together with the paint as will be described later.

  The color pigment contained in the first paint is a specific color selected from a number of preset appearance paint colors, that is, contained in the following third paint that forms the third paint film 7 on the outer plate surface 2. By using the same ones as those described above, the first coating film 5 is colored in the appearance coating film color set to the same color as the third coating film 7 or an approximate color. Specifically, the above color pigments include titanium oxide, zinc white, carbon black, cadmium red, molybdenum red, chromium yellow, chromium oxide, Prussian blue, cobalt blue, azo pigment, phthalocyanine pigment, quinacridone pigment, isoindoline. One kind selected from colored pigments such as a pigment, a selenium pigment, and a perylene pigment can be used, or two or more kinds can be mixed and used.

  As the resin component, it is preferable to use a thermosetting resin composition. Examples of the thermosetting resin composition include a base resin such as an acrylic resin, a polyester resin, and an alkyd resin having a crosslinkable functional group, a melamine resin, a urea resin, a polyisocyanate compound (including a block body), and the like. Examples thereof include a composition comprising a crosslinking agent, an acid / epoxy crosslinked resin composition comprising an acid group-containing resin and an epoxy group-containing resin as main components. In addition, as the resin component, a thermosetting resin having a crosslinkable functional group such as a hydroxyl group, a carboxyl group, and an epoxy group, and a base resin such as an acrylic resin, a polyester resin, and an alkyd resin, and a crosslinking agent such as a melamine resin. More preferably, the composition is used.

  Thereafter, in the second coating film forming step K2, in the second coating film forming section 15 having the electrostatic coating machine 14 or the like, the opening / closing body 13 composed of the side door or the like in the open state is displaced to a substantially closed state. Thereafter, the second coating film 6 having a high base concealing property is applied on the base coating film 4 on the outer panel surface 2 by spraying the second coating material onto the outer panel surface 2 of the automobile body 1 to cause electrostatic adsorption. Form. The second paint forms a first coating film 5 having a base concealing property, and dissolves a pigment for coloring the first coating film 5 into a predetermined color, a resin component, and the like in a solvent made of water. Or it is a water-soluble paint obtained by making it disperse | distribute, and can contain an extender, an anti-settling agent, a coating surface regulator, a ultraviolet absorber, a ultraviolet stabilizer, an adhesion imparting agent, etc. as needed.

  Examples of the pigment contained in the second paint include those selected from the group consisting of carbon black, titanium oxide, iron oxide, aluminum flakes, and combinations thereof. In addition, if necessary, predetermined colored pigments, that is, zinc white, cadmium red, molybdenum red, chrome yellow, chromium oxide, Prussian blue, cobalt blue, azo pigment, phthalocyanine pigment, quinacridone pigment, isoindoline pigment One kind selected from colored pigments such as selenium pigments and perylene pigments may be used, or two or more kinds may be mixed and used.

  As the resin component contained in the second paint, it is preferable to use a thermosetting resin composition as in the first paint. Examples of the thermosetting resin composition include a base resin such as an acrylic resin, a polyester resin, and an alkyd resin having a crosslinkable functional group, a melamine resin, a urea resin, a polyisocyanate compound (including a block body), and the like. Examples thereof include a composition comprising a crosslinking agent, an acid / epoxy crosslinked resin composition comprising an acid group-containing resin and an epoxy group-containing resin as main components. In addition, as the resin component, a thermosetting resin having a crosslinkable functional group such as a hydroxyl group, a carboxyl group, and an epoxy group, and a base resin such as an acrylic resin, a polyester resin, and an alkyd resin, and a crosslinking agent such as a melamine resin. More preferably, the composition is used.

  As the pigment contained in the second paint, for example, a gray-colored pigment made of carbon black, titanium dioxide, or the like was used, thereby corresponding to the third paint film 7 formed on the second paint film 6. The color of the 2nd coating film 6 formed with the said 2nd coating material is set to the achromatic color which has brightness. That is, the color of the second coating film 6 is set to an achromatic color having, for example, five levels of brightness composed of dark gray, gray, ride gray, super light gray, and white and having an excellent background hiding function. It has become. When the content of the color pigment is set higher than usual, that is, when the content of the color pigment is set so that the brightness of the second coating film 6 is lower than the brightness corresponding to the third coating film 7. Therefore, it is possible to sufficiently ensure the base concealing property of the second coating film 6 with a simple configuration.

  Thereafter, in the third coating film forming step K3, in the third coating film forming section 17 having the electrostatic coating machine 16 and the like, while maintaining the opening / closing body 13 composed of the side door or the like in a substantially closed state, the outer plate surface The third coating film 7 is formed by spray-coating the third coating material on the second coating film 6 in an uncured state without curing the second coating film 2. The third paint comprises a coloring pigment for causing the third paint film 7 to have a predetermined appearance paint color, together with the second paint film 7 alone or together with the second paint film 7, a resin component, etc. Alternatively, it is a liquid paint obtained by dissolving or dispersing in a solvent comprising water, and optionally contains extender pigments, anti-settling agents, coating surface conditioners, UV absorbers, UV stabilizers, adhesion promoters, etc. Can be made.

  The color pigment contained in the third paint has a lower background concealment than the second paint film 6 and a specific color selected from a number of preset paint film colors, that is, the first paint. A material that colors the third coating film 7 in the same color as or similar to the film 5 is used. Specifically, the above color pigments include titanium oxide, zinc white, carbon black, cadmium red, molybdenum red, chromium yellow, chromium oxide, Prussian blue, cobalt blue, azo pigment, phthalocyanine pigment, quinacridone pigment, isoindoline. One kind selected from colored pigments such as a pigment, a selenium pigment, and a perylene pigment can be used, or two or more kinds can be mixed and used.

  In the spray coating of the second and third paints using the electrostatic coating machines 14 and 16, as in the case of the first paint, for example, an object to be coated made of the automobile body 1 is used as an anode (+), By using the electrostatic coating machine 11 as a cathode (-) and applying a high voltage of several tens of kV between them to form an electrostatic field, the coating particles are charged on the cathode (-) and sprayed. This is done by adsorbing the paint particles to the object to be coated (automobile body 1) by electrostatic attraction. The spray pattern of the paint from the electrostatic coating machines 14 and 16 is adjusted according to the flow rate of the shaving air blown out together with the paint from the spray gun.

  And the place which the coating material sprayed from the said electrostatic coating machines 14 and 16 may wrap around to the inner-plate surface 3 side, for example, the vicinity of the opening part 2a formed in the outer-plate surface 2 as shown in FIG. Then, in the third coating film forming step K3, the flow rate of the shaving air A blown from the spray gun 16a of the electrostatic coating machine 16 is set higher than when the third paint is sprayed on other portions. Has been. As a result, the third paint particles 31 are positively supplied into the interior of the automobile body 1 from the opening 2a, and the wraparound of the third paint particles 31 toward the inner plate surface 3 side is promoted.

  In the preheating step K4 performed after the first to third coating film forming steps K1 to K3 are finished, the vehicle body 1 conveyed to the preheating portion 23 is blown with hot air and irradiated with infrared rays, or a combination thereof is used for the vehicle body. By heating the outer plate surface 2 and the inner plate surface 3, the water in the first to third paints is evaporated, and the first to third coating films 5 to 7 are simultaneously brought into a semi-cured state.

  Thereafter, the process proceeds to the inner plate clear coating film forming step K5 to open the opening / closing body 13, and then the clear coating material is applied to the first coating film 5 on the inner plate surface 3 by air spray, airless spray, static It is applied by an inner plate clear coating film forming unit 24 equipped with a spray coating machine such as an electric system to form a clear coating film 8. As the clear coating film, for example, a solvent-type paint containing a thermosetting resin composition and a solvent is used, and if necessary, a bright pigment, a coloring pigment, an anti-settling agent, a coating surface conditioner, An ultraviolet absorber, an ultraviolet stabilizer, an adhesion-imparting agent, and the like can be appropriately contained. The glitter pigment and the color pigment are preferably blended to such an extent that the transparency of the clear coating film 8 is not impaired.

  Next, the process proceeds to the outer plate clear coating film forming step K6, and after the open / closed opening body 13 is displaced to the substantially closed state, the third coating of the outer plate surface 2 is performed in the same manner as the inner plate clear coating film forming step K5. On the film 7, a clear coating film coating made of a solvent-type coating is applied by an outer plate clear coating film forming unit 25 equipped with a spray coating machine such as an air spray, an airless spray, an electrostatic method, etc. After forming 9, the automobile body 1 is heated at a temperature of about 140 ° C. for about 30 minutes in the baking and drying step K7 to simultaneously cure the coating films.

  A first coating film forming step of forming a first coating film 5 for coloring the appearance coating film color by applying the first coating material on the inner plate surface 3 of the automobile body 1 on which the base coating film 4 is formed as described above. K1, a second coating film forming step K2 for applying a second paint on the outer plate surface 2 of the automobile body 1 to form a second coating film 6 that develops a base concealing property, and the second coating film 6 After the formation of the film, a third paint is applied thereon and has a lower background concealing property than the second paint film, and the same color as the first paint film or the same color as or similar to the first paint film alone or together with the second paint film In the coating method and apparatus for an automobile body 1 including the third coating film forming step K3 for forming the third coating film 7 that develops the appearance coating color, the third coating material is formed in the third coating film forming step K3. Is applied to the outer plate surface 2 of the automobile body 1 while the third coating is promoted to circulate toward the inner plate surface 3 side. Since it is configured to be applied to the plate surface 2, the aesthetic appearance caused by the dust of the second paint applied on the outer plate surface 2 of the automobile body 1 adheres to the first coating film 5 of the inner plate surface 3. The second paint has versatility while easily and effectively preventing the decrease in the cost, and there is an advantage that the equipment cost can be reduced and the labor of the painting work can be effectively simplified.

  That is, after the completion of the first coating film forming step K1 for forming the first coating film 5 on the inner plate surface 3 of the automobile body 1 as described above, the second and third portions are formed on the outer plate surface 2 of the automobile body 1. When the second and third coating film forming steps K2 and K3 for forming the coating films 6 and 7 are provided, the third coating film 7 formed on the outer plate surface 2 of the automobile body 1 is the inner plate. There is an advantage that it is not affected by the first paint applied to the surface 3, and the deterioration of the beauty caused by this can be surely prevented.

  However, on the other hand, the dust of the second paint sprayed in the second coating film forming step K2 to form the second coating film 6 on the base coating film 4 of the outer plate surface 2 enters the vehicle body, As shown in FIG. 3, there is a possibility of adhering to the peripheral portion of the inner plate surface 3 or the like. When the first coating film 5 and the second coating film 6 are set to different colors, for example, the second coating film 6 is set to an achromatic color, and the first coating film 5 is set to the third color. When it is set to the same or similar chromatic color as the coating film 7, the dust coating film 20 of the second paint adhered to the inner plate surface 3 and the appearance coating color of the inner plate surface 3 are developed. There is a possibility that the aesthetic appearance is lowered by exhibiting a different hue from the first coating film 5.

  In the first embodiment according to the present invention, the third paint is sprayed on the outer plate surface 2 of the automobile body 1 by the flow rate of the shaving air A blown from the electrostatic coating machine 16 in the third coating film forming step K2. In addition, the flow rate of the shaving air A is set at a location where the paint sprayed toward the outer plate surface 2 of the automobile body 1 may circulate toward the inner plate surface 3 side (for example, the location where the opening 2a is installed). The third paint particles 31 are positively supplied into the interior of the vehicle body 1 from the opening 2a by raising the third paint compared to when the third paint is sprayed on other parts. Thus, the third paint is configured to promote the wrapping around to the inner plate surface 3 side.

  As described above, when the third coating material is applied to the outer plate surface 2 of the automobile body 1 in the third coating film formation step K3, the third coating material is configured to promote the wraparound to the inner plate surface 3 side. The third paint adheres over a wider range than the dust paint film 20 formed by the dust of the second paint sprayed in the second paint film forming step K2 adhering to the inner plate surface 3. To do. For this reason, the surface of the dust paint film 20 of the second paint is covered with the dust paint film 21 of the third paint that develops the same or similar appearance paint color as the first paint. It is possible to prevent the dust coating film 20 from being exposed to the outside.

  Accordingly, the color of the second coating film 6 is set to an achromatic color having five levels of brightness composed of, for example, dark gray, gray, ride gray, super light gray, and white, and the appearance coating is performed only by the third coating film 7. If the film color is developed, or the appearance paint film color is developed by both the second paint film 6 and the third paint film 7, the second paint for the second paint film 6 is versatile. Can be given. For this reason, compared with the case where the second coating film 6 is configured to have the same color as the third coating film 7, the piping necessary for applying the second coating material is reduced and the structure of the coating apparatus is reduced. While effectively simplifying, the effect of reducing the aesthetics caused by the dust of the second paint applied on the outer plate surface 2 of the automobile body 1 adhering to the first coating 5 on the inner plate surface 3 is effective. There is an advantage that can be prevented. In addition, the second coating film 6 is compared with the number of pipe changes performed each time the coating material forming the first and third coating films 5 and 7 that develop appearance coating colors having various colors is changed. There is also an advantage that the number of operations for changing the piping when forming the coating can be greatly reduced to make the painting operation more efficient.

  And since it is not necessary to set the color of the said 2nd coating film 6 to the same or approximate color as an appearance coating film color, as shown in FIG. 4, carbon black 18 is used for the 2nd coating material which forms the 2nd coating film 6. As shown in FIG. Or the like, or by setting the content of the color pigment 19 with respect to the second paint to be higher than usual, the background hiding property of the second coating film 6 is effectively improved. Can be made. Accordingly, by omitting the operation of applying the intermediate coating on the base coating film 4 formed on the outer plate surface 2 and drying it, the process of the painting operation is simplified while the outer coating surface 2 is applied. The irradiation of visible light, ultraviolet rays, or the like is absorbed or reflected by the carbon black 18 or the color pigment 19 blended in the second coating film 6 to prevent the ultraviolet rays from reaching the base coating film 4. it can. For this reason, there exists an advantage that the early deterioration of the base coating film 4 resulting from irradiating the base coating film 4 with an ultraviolet-ray with a simple structure can be prevented effectively.

  In particular, the brightness of the second coating film 6 formed in the second coating film forming step K2 can be set to a third coating film by setting the content of the color pigment 19 with respect to the second coating more than usual as described above. When configured to be set lower than the third coating film 7 formed in the forming step K3, omitting the base concealing pigment composed of the carbon black 18 or the like, or reducing the content thereof, Since the base concealability of the second coating film 6 can be ensured, the early deterioration of the base coating film 4 due to the irradiation of the base coating film 4 with ultraviolet rays can be effectively suppressed with a simpler configuration. There is an advantage that you can.

  Further, as shown in the first embodiment, a clear coating film 8 is formed on the first coating film 5 formed on the inner plate surface 3 of the automobile body 1 at least after the first coating film forming step K1. When the inner plate clear coating film forming step K5 is provided, the dust coating film to which the second and third paints sprayed in the second and third coating film forming steps K2 and K3 adhere is attached. Even when 20 and 21 are formed on the first coating film 5 on the inner plate surface 3, the smoothness and aesthetics of the inner plate surface 3 can be effectively maintained, and the first coating film 5 is applied with a clear coating. It can be protected by the film 8 to effectively improve its weather resistance and the like.

  Furthermore, in the said 1st Embodiment, the outer plate | board which forms the clear coating film 9 on the said 3rd coating film 7 formed on the outer-plate surface 2 of the motor vehicle body 1 at least after the 3rd coating-film formation process K3. Since the clear coating film forming process K6 is provided, the smooth coating film and the weather resistance can be effectively maintained by covering the third coating film 7 with the clear coating film 9. Therefore, even when the clear paint or the like sprayed toward the inner plate surface 3 in the inner plate clear coating film forming step K5 adheres to the third coating film 7 on the outer plate surface 2, the outer plate surface 2 Smoothness can be sufficiently ensured.

  In the said 1st Embodiment, since the 1st-3rd coating films 5-7 were formed using the 1st-3rd coating material which consists of a water-soluble coating material, an organic solvent is used as a solvent of the said 1st-3rd coating material. In this case, there is an advantage that there is no problem that the solvent evaporated at the time of drying the paint is discharged to the outside. Moreover, since the preheating step K4 for pre-drying the first to third coating films 5 to 7 after application of the first to third coatings made of the water-soluble coating is provided, the subsequent inner plate clear coating film forming step K5 and the outside Even when the clear coating films 8 and 9 are formed on the first and third coating films 5 and 7 in the plate clear coating film forming step K6, moisture in the first to third coating materials is not vaporized. There are no problems such as remaining, and the first to third coating films 5 to 7 made of the first to third paints can be appropriately cured.

  It should be noted that the flow rate of the shaving air A is set at a location where the third paint sprayed toward the outer plate surface 2 of the automobile body 1 in the third coating film forming step K3 may go around to the inner plate surface 3 side. Instead of spraying the third paint on the other parts, the first paint is configured to promote the wraparound of the third paint to the inner plate surface 3 side of the automobile body 1, instead of the first embodiment, As shown in the second embodiment below, the electrostatic sprayer 16 sprays the paint sprayed toward the outer plate surface 2 of the automobile body 1 where the paint may wrap around the inner plate surface 3 side. The potential difference between the third paint and the outer plate surface 2 of the automobile body 1 is made narrower than when the third paint is sprayed on other portions, so that the third paint wraps around the inner plate surface 3 side. You may comprise.

  That is, as in the second embodiment shown in FIG. 5, when the spray gun 16a of the electrostatic coating machine 16 reaches the vicinity of the opening 2a, the outer plate surface of the automobile body 1 is connected via the potential control means 22. 2 to reduce the positive potential applied to the spray gun 16a or to reduce the negative potential applied to the spray gun 16a via a potential control means (not shown). The potential difference between the particles 31 of the third paint sprayed from and the outer plate surface 2 of the automobile body 1 is controlled to be narrower than when the third paint is sprayed on other portions. As a result, the amount of the third paint adsorbed on the outer plate surface 2 can be reduced, and the amount of the third paint that wraps around from the opening 2a toward the inner plate surface 3 can be increased correspondingly. The third paint is applied over a wider range than the dust paint film 20 of the second paint formed on the inner plate surface 3, and the dust paint film 20 of the second paint is formed by the dust paint film 21 of the third paint. Can be reliably concealed.

  In addition, as in the third embodiment shown in FIG. 6, in the automobile body 1 in which the opening 2b is formed in the outer plate surface 2 and the opening / closing body 13 for opening and closing the opening 2b is provided, In the coating film forming step K3, when the third paint is sprayed from the spray gun 16a of the electrostatic coating machine 16, the opening angle of the opening / closing body 13 is made larger as shown by the solid line than in the normal time shown by the virtual line. Thus, the opening area of the opening 2b may be increased so that the third coating material wraps around the inner plate surface 3 side.

  When configured as described above, the flow resistance of the third paint particles 31 passing through the opening 2b can be reduced by an extremely simple operation of slightly increasing the opening angle of the opening / closing body 13 from the normal time. Thus, the wraparound of the third paint to the inner plate surface 3 side can be promoted. For this reason, even if the dust coating film 20 is formed by the dust of the second coating sprayed in the second coating film forming step K2 adhering to the inner plate surface 3, the formation range of the dust coating film 20 is formed. Is covered with a dust coating film 21 formed by a third coating material for the third coating film 7 that develops an appearance coating color of the same color as or similar to that of the first coating film 5, thereby forming the second coating material. It is possible to effectively prevent the dust coating film 20 from being exposed.

  Further, as in the fourth embodiment shown in FIG. 7, in the third coating film forming step K3, the static direction is configured so that the spray direction of the third paint sprayed on the outer plate surface 2 of the automobile body 1 can be adjusted. The third coating material is sprayed using the electropainting machine 16, and the portion sprayed on the outer plate surface 2 of the automobile body 1 may go around the inner plate surface 3 side (for example, an opening). In the vicinity of the installation portion of the portion 2a), the inner plate is adjusted by adjusting the spray direction of the paint so that the particles 31 of the third paint sprayed toward the outer plate surface 2 of the automobile body 1 are concentrated on the opening 2a. You may comprise so that the surroundings of the 3rd coating material to the surface 3 side may be accelerated | stimulated. Even when configured in this manner, there is an advantage that it is possible to easily and effectively prevent a decrease in aesthetics due to the exposure of the dust coating film 20 of the second paint.

DESCRIPTION OF SYMBOLS 1 Automobile body 2 Outer plate surface 3 Inner plate surface 4 Base coating 5 First coating 6 Second coating 7 Third coating 8 Clear coating on inner plate 9 Clear coating 12 on outer plate 12 First coating Film forming section 13 Opening and closing body 15 Second coating film forming section 16 Electrostatic coating machine 17 Third coating film forming section 22 Potential control means (promotion means)
24 Inner plate clear coating film forming part 25 Outer plate clear coating film forming part

Claims (11)

  A first coating film forming step for forming a first coating film for coloring an appearance coating color by applying a first coating material on an inner plate surface of an automobile body on which a base coating film is formed; A second coating film forming step of applying a second coating material on the surface to form a second coating film having a base concealing property; and after forming the second coating film, a third coating material is applied thereon to form the second coating film. A third coating film is formed which has a lower background concealing property than two coating films and develops an appearance coating color of the same color as or similar to the first coating film together with the third coating film alone or with the second coating film. A method of coating an automobile body comprising a third coating film forming step, wherein the third coating material is applied to the outer plate of the automobile body when the third coating material is applied to the outer plate surface in the third coating film forming step. A method for painting a car body, characterized in that it is constructed so as to promote the wrapping around the surface.   The spray pattern of the third paint sprayed on the outer plate surface of the automobile body in the third coating film forming step is configured to be adjusted according to the flow rate of the shaving air, and directed toward the outer plate surface of the automobile body. In places where the sprayed paint may circulate toward the inner plate surface side, the flow rate of the shaving air is increased as compared with the case where the third paint is sprayed on the other parts, so that the inner plate surface side of the automobile body 2. The method for painting an automobile body according to claim 1, wherein the third paint is circulated around the vehicle.   In the third coating film forming step, the vehicle body and the electrostatic coating machine are charged to the opposite electrodes so that the third paint is sprayed on the outer plate surface of the vehicle body, and directed toward the outer plate surface of the vehicle body. In places where the sprayed paint may circulate toward the inner plate surface side, the potential difference between the third paint and the outer plate surface of the car body should be made narrower than when the third paint is sprayed on other parts. The automobile body painting method according to claim 1, wherein the third paint is circulated around the inner plate surface side of the automobile body.   In a portion where an opening is formed on the outer plate surface of the automobile body and an opening / closing body for opening / closing the opening is provided, the opening / closing body is opened to increase the opening area of the opening, thereby 2. The method of painting an automobile body according to claim 1, wherein the third paint is circulated around the inner plate surface side of the vehicle.   In the third coating film forming step, the third coating material is sprayed using an electrostatic coating machine configured to be capable of adjusting the spraying direction of the coating material on the outer plate surface of the automobile body. In places where the paint sprayed on the outer plate surface may wrap around to the inner plate surface side, the electrostatic charge is applied so that the third paint sprayed toward the outer plate surface of the automobile body is concentrated on the inner plate surface side. The method of painting an automobile body according to claim 1, wherein the spraying direction of the painting machine is adjusted so as to promote the third paint to wrap around the inner plate surface of the automobile body.   The said 2nd coating film formation process forms the 2nd coating film whose brightness is lower than a 3rd coating film on the outer-plate surface of a motor vehicle body, The any one of Claims 1-5 characterized by the above-mentioned. How to paint car bodies in Japan.   The inner plate clear coating film forming step for forming a clear coating film on the inner plate surface of the automobile body is provided at least after the first coating film forming step. The method of painting an automobile body as described.   The outer plate clear coating film forming step for forming a clear coating film on the outer plate surface of the automobile body is provided at least after the third coating film forming step. The method of painting an automobile body as described.   A first coating film forming portion for forming a first coating film for coloring an appearance coating color by applying a first coating material on an inner plate surface of an automobile body having a base coating film formed thereon; A second coating film forming portion for applying a second coating material on the surface to form a second coating film having a base concealing property; and after forming the second coating film, a third coating material is applied on the second coating film forming portion. A third coating film is formed which has a lower background concealing property than two coating films and develops an appearance coating color of the same color as or similar to the first coating film together with the third coating film alone or with the second coating film. An automobile body coating apparatus comprising a third coating film forming portion, wherein the third coating material is applied to the inner plate surface when the third coating material is applied to the outer plate surface of the automobile body by the third coating film forming portion. An automobile body coating apparatus, comprising a promoting means for promoting sneaking to the side.   The automobile body coating apparatus according to claim 9, further comprising an inner plate clear coating film forming portion that forms a clear coating film on the first coating film on the inner plate surface.   11. The automobile body coating apparatus according to claim 9 or 10, further comprising an outer plate clear coating film forming part for forming a clear coating film on the third coating film on the outer plate surface.

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