JP4127212B2 - Painting method - Google Patents

Description

  The present invention relates to a coating method that is preferable when applied to an automobile body or the like, and more particularly, to a two-coat one-bake coating method in which an intermediate coating and a top coating are applied wet-on-wet and are baked simultaneously.

  Automobile body coating systems include undercoating paints, such as electrodeposition coatings based on epoxy resins, intermediate coatings based on polyester resins, and top coatings based on polyester coatings. Using three types of paint, after applying the undercoat, this is baked, and after applying the intermediate coat on the cured undercoat layer, this is baked and overcoated on the cured intermediate coat layer. A so-called three-coat three-bake coating method, which is completed by baking after coating, is employed.

  However, in such a 3-coat 3-bake coating system, a drying furnace is required for each of the undercoating process, the intermediate coating process, and the top-coating process, and thus a wide process space for installing the drying furnace is required. The energy consumed in the drying furnace is reflected in the production cost of the automobile.

  Therefore, in order to solve the above problems by reducing the number of drying ovens provided in these three processes to two or less, a method of applying the base coat and the intermediate coat with wet-on-wet, or an intermediate coat and a top coat A method of applying a wet-on-wet method (for example, see Patent Document 1) has been studied.

However, in the coating system in which the intermediate coating and top coating are applied wet-on-wet and baked at the same time, it is not possible to provide a sanding process to smooth the surface of the intermediate coating layer. There is a problem that irregularities such as rounds formed on the surface of the layer or intermediate coating layer appear on the surface of the top coating layer, and as a result, the smoothness of the top coating layer typified by sharpness decreases. there were.
JP 2002-153805 A

An object of this invention is to provide the coating method which can implement | achieve the wet-on-wet coating type | system | group of intermediate coating and top coating while maintaining a sharpness.
In order to achieve the above object, according to the present invention, after an undercoat paint is applied to an object to form an undercoat paint film layer, an intermediate coat paint is applied to the undercoat paint layer. Forming a layer, applying a top coating to the uncured intermediate coating layer to form a top coating layer, and simultaneously baking at least the coating layer above the under coating layer , At least an upper layer than the undercoat coating layer includes colored first resin particles having an average particle diameter of 30 nm to 1 μm and a glass transition point higher than the baking temperature, and a colorant having an average particle diameter exceeding 1 μm. A coating method for forming a first colored coating layer is provided.

In the present invention, when the intermediate coating and the top coating are applied wet-on-wet, in addition to a general coloring material having an average particle diameter exceeding 1 μm, colored resin particles having an average particle diameter of 30 nm to 1 μm are added. The contained colored coating film layer is formed at least above the undercoat coating film layer. And, since the resin particles fill the space between the particles of the general coloring material, the roundness of the undercoat coating layer and the intermediate coating layer is reduced, and the smoothness of the surface of the top coating layer is improved. In addition, it is possible to realize a wet-on-wet coating system of intermediate coating and top coating while maintaining the sharpness. As a result, a drying furnace for intermediate coating, which has been conventionally required, becomes unnecessary, and the process space of the coating line is significantly reduced. Further, since the heat energy used in the drying furnace is not necessary, the production cost can be reduced.

[First Embodiment]
A description will be given below based on the drawings according to the first embodiment of the present invention. FIG. 1 is a process diagram showing a coating method according to the first embodiment of the present invention, FIG. 2 is a plan view showing an example of a line in the middle and top coating process of FIG. 1, and FIG. 3 is according to the first embodiment of the present invention. It is sectional drawing which shows a laminated coating film.

  The coating method according to the first embodiment of the present invention, which will be described below, is a three-coat coating system of undercoating, intermediate coating, and topcoating. After the base coating is applied and baked and cured, the intermediate coating is applied. This is a so-called three-coat two-bake coating system in which a top coat and a top coat are applied wet-on-wet, and these are simultaneously baked and cured.

  Speaking of intermediate coating and top coating, it is a coating system of 2 coats and 1 bake. More specifically, for example, when the top coating is a solid paint, it is 2 coats and 1 bake. For example, the top coating is a metallic system. In the case of including a base paint and a clear paint, such as paint, 3 coats and 1 bake. In the following first embodiment, a case will be described in which the top coat paint includes a base paint and a clear paint.

  In the painting method according to the present embodiment, first, an automobile body B assembled as a white body is carried into the painting factory from the vehicle body assembly process, and as shown in FIG. The adhered oil and dust are removed, and a rust-proof chemical film is formed on the steel plate surface constituting the body B.

  In the electrodeposition coating process 2, the automobile body B (object to be coated) on which the cleaning and chemical conversion film is formed through the pretreatment process 1 is immersed in an electrodeposition coating tank filled with the electrodeposition paint. In this electrodeposition coating tank, when a high voltage of, for example, 300 V is applied to the electrodeposition paint, the electrodeposition paint is electrophoresed, whereby an uncured electrodeposition coating layer 20 (undercoat film) is applied to the body B. Layer, see FIG. 3).

  Examples of the electrodeposition paint applied in this electrodeposition coating step 2 include epoxy resins (including polyamine resins typified by amine-added epoxy resins), acrylic resins, polybutadiene resins, alkyd resins, and polyester resins. And the like, and a cationic electrodeposition coating material or an anionic electrodeposition coating material obtained by adding a coloring material, a curing agent, or the like to the main component. In the case of an anionic electrodeposition paint, the coated side is the positive electrode and the electrodeposition paint side is the negative electrode. In the case of the cationic electrodeposition paint, the coated side is the negative electrode and the electrodeposition paint side is the positive electrode. Moreover, as a hardening | curing agent added to this electrodeposition coating material, a block polyisocyanate compound, an amino resin, etc. can be mentioned.

  Next, in the electrodeposition coating step 2, the body B discharged from the electrodeposition coating tank is washed away with an excess electrodeposition paint adhering to the body B in the electrodeposition washing step 3.

  The body B which has been subjected to the electrodeposition water washing is then carried into an electrodeposition drying furnace in the undercoat baking process 4 and baked at, for example, 160 ° C. to 180 ° C. for 15 minutes to 30 minutes to cure the electrodeposition coating layer 20. Then, it is carried into the intermediate top coating process 5. As shown in FIG. 3, the electrodeposition coating layer 20 thus formed constitutes the lowermost layer of the laminated coating 10 and has a thickness of 10 to 40 μm, for example.

  In the intermediate top coating process 5, first, in the intermediate coating process 6, as shown in FIG. 2, the intermediate coating apparatus 6a applies the intermediate coating to the surface of the cured electrodeposition coating layer 20, and the intermediate coating is performed. After the film layer 30 (see FIG. 3) is formed and the intermediate coating flash-off device 6b flashes off the intermediate coating film layer 30, the intermediate coating film layer 30 is not baked and cured, and the top coating base coating process is performed. Unload to 7. The intermediate coating layer 30 formed in the intermediate coating step 6 constitutes the upper layer of the electrodeposition coating layer 20 in the laminated coating 10, as shown in FIG. The film thickness is, for example, 15 to 45 μm.

  As the intermediate coating applied in the intermediate coating step 6, the main component is a polyester resin, an acrylic resin, a vinyl chloride vinyl acetate copolymer resin, a urethane resin, a cellulose resin, and the like, and a coloring material or additive is added thereto. Examples include a thermosetting paint added, a room temperature curable paint, or a two-component curable paint diluted with a solvent.

  In the intermediate coating material according to the present embodiment, as a coloring material, an existing coloring material having an average particle diameter exceeding 1 μm, and an atomized coloring material having an average particle diameter of, for example, 30 nm to 1 μm obtained by refining an existing coloring material; , Has been added.

  In this embodiment, in addition to the existing colorant, the finely divided fine particle colorant is contained in the intermediate coating material, so that the atomized colorant fills the space between the particles of the existing colorant. The roundness of the film layer 20 and the intermediate coating film layer 30 can be reduced, and the smoothness of the surface of the laminated coating film 10 can be improved. It is practically difficult to make the average particle diameter of the atomized colorant smaller than 30 nm. Further, if the average particle diameter exceeds 1 μm, it becomes too large relative to the existing colorant particles, and cannot fill between the colorant particles, and the surface of the multilayer coating film 10 is smooth. May not be improved.

  In addition, the atomized colorant contained in the intermediate coating material according to the present embodiment has a glass transition point Tg higher than the baking temperature of the intermediate coating layer 30, specifically, 100 ° C. to 180 ° C. It has a glass transition point Tg of ° C.

  In the present embodiment, since the fine particle colorant contained in the intermediate coating has a glass transition point Tg of 100 ° C. to 180 ° C., the atomized colorant is baked when the intermediate coating layer 30 is baked. Since the space between the particles of the existing colorant is reliably filled without thermal deformation, the smoothness of the surface of the laminated coating film 10 is further improved.

  Examples of the additive added to the intermediate coating material include waxes such as polyethylene wax and polypropylene wax, dispersants and the like, and examples of the solvent include water, aromatic hydrocarbon solvents or hydrocarbons. Examples thereof include ester solvents (ester solvents, ketone solvents, alcohol solvents, etc.).

  Next, in the top coat base coating process 7, the top coat base coating device 7a applies the top coat base paint on the surface of the uncured intermediate coat film layer 30 by wet on wet to form the top coat base coat layer 70 (FIG. 3). And the top coat base flash-off device 7b flashes off the top coat base coating layer 70, and then the top coat clear coating step without baking and curing the intermediate coating film 30 and the top coating base coating layer 70. Carry out to 8. The top coat base coating layer 70 formed in the top coating step 7 constitutes the upper layer of the intermediate coating layer 30 in the laminated coating 10, and the film thickness after baking and curing is, for example, 15 to 45 μm. is there.

  The top coat base paint applied in this top coat base coating step 7 is mainly composed of polyester resin, acrylic resin, polyvinyl acetate copolymer resin, urethane resin, cellulose resin, etc., and coloring materials and additives are added thereto. Examples include a thermosetting paint added, a room temperature curable paint, or a two-component curable paint diluted with a solvent.

  Examples of the additive added to the overcoat base paint include waxes such as polyethylene wax and polypropylene wax, dispersants and the like, and examples of the solvent include water, an aromatic hydrocarbon solvent or carbonization. Examples thereof include hydrogen solvents (ester solvents, ketone solvents, alcohol solvents, etc.).

  Next, in the overcoat clear coating process 8, after the topcoat clear coating apparatus 8a applies the topcoat clear paint to the surface of the uncured topcoat base coat layer 70 by wet-on-wet, the intermediate coat layer 30 and the topcoat The base coating film layer 70 and the top coat clear coating film layer 80 are carried out to the setting booth 8b without being baked and cured. As shown in FIG. 3, the topcoat clear coating film layer 80 formed in the topcoat clear coating step 8 constitutes the uppermost layer of the multilayer coating film 10, and the film thickness after baking and curing is, for example, 15 to 45 μm.

  The top coat clear paint applied in this top coat clear coating step 8 is mainly composed of a polyester resin, an acrylic resin, a vinyl chloride vinyl acetate copolymer resin, a urethane resin, a cellulose resin, and the like, and a colorant or an additive is added thereto. Examples include a thermosetting paint added, a room temperature curable paint, or a two-component curable paint diluted with a solvent.

  Examples of the additive that is added to this clear clear paint include waxes such as polyethylene wax and polypropylene wax, and dispersants. Examples of the solvent include water, aromatic hydrocarbon solvents, or hydrocarbons. Examples thereof include ester solvents (ester solvents, ketone solvents, alcohol solvents, etc.).

  Each of the coating apparatuses 6a to 8a shown in FIG. 2 is, for example, an automatic coating apparatus, a coating robot, or the like, and the coating method is not particularly limited.

  The vehicle body B in which the intermediate coating, the top coating base coating, and the top coating clear coating are applied wet-on-wet in the intermediate top coating process 5 from the setting booth 8b in the middle top coating drying furnace 9a. The intermediate coating film layer 30, the top coating base coating film layer 70, and the top coating clear coating film layer 80 are simultaneously cured by, for example, baking at 80 ° C. to 160 ° C. for 10 minutes to 30 minutes. Is done.

  As described above, in the coating method according to the present embodiment, in addition to the existing colorant, the atomized colorant having an average particle diameter of 30 nm to 1 μm is contained in the intermediate coating material, whereby the atomized colorant is obtained. Fills the existing colorant particles, reduces the rounds of the undercoat layer and intermediate coat layer, and improves the smoothness of the surface of the laminated coating layer. It is possible to realize a wet-on-wet coating system with painting and top coating. As a result, a drying furnace for intermediate coating, which has been conventionally required, becomes unnecessary, and the process space of the coating line is significantly reduced. Further, since the heat energy used in the drying furnace is not necessary, the production cost can be reduced.

  In the coating method according to the present embodiment, the atomized colorant contained in the intermediate coating has a glass transition point Tg of 100 ° C. to 180 ° C., so that the intermediate coating layer is baked. Since the atomized colorant reliably fills the space between the existing colorant particles without being thermally deformed, the smoothness of the surface of the laminated coating film can be further improved.

[Second Embodiment]
FIG. 4 is a sectional view showing a laminated coating film according to the second embodiment of the present invention.

  As shown in FIG. 4, the laminated coating film 10 a according to this embodiment includes an electrodeposition coating layer 20 formed on the surface of the automobile body B, and a colored coating formed on the surface of the electrodeposition coating layer 20. The film layer 50, the intermediate coating film layer 40 formed on the surface of the colored coating film layer 50, the top coating base coating film layer 70 formed on the surface of the intermediate coating film layer 40, and the top coating base coating It consists of an overcoat clear coating layer 80 formed on the surface of the film layer 70.

  In the multilayer coating film 10a according to the present embodiment, the intermediate coating film layer 30 containing the atomized coloring material in addition to the existing coloring material in the multilayer coating film 10 according to the first embodiment shown in FIG. In addition to the existing colorant, the intermediate coating film layer 40 is changed to an intermediate coating film layer 40 that does not contain atomized coloring material, and between the intermediate coating film layer 40 and the electrodeposition coating film layer 20. The colored coating film layer 50 containing the atomized colorant is laminated, and more coating layers are laminated than the laminated coating film 10 according to the first embodiment. In addition, since the electrodeposition coating film layer 20, the top coat base coating film layer 70, and the top coating clear coating film layer 80 are the same as those in the first embodiment, their detailed description is omitted.

  The colored coating layer 50 and the intermediate coating layer 40 of the multilayer coating 10a according to this embodiment are formed in the intermediate coating step 6 in FIG.

  In the intermediate coating process 6 according to the present embodiment, after the electrodeposition coating layer 20 is baked and cured in the undercoat baking process 4, first, a polyester resin, an acrylic resin, a polyvinyl chloride vinyl chloride copolymer resin, a urethane resin, A thermosetting paint or a room temperature curable paint or a two-component curable paint prepared by adding a colorant or an additive to cellulose resin or the like as a main component is diluted with a solvent by an intermediate coating apparatus 6a. Then, it is applied to the surface of the cured electrodeposition coating layer 20 to form a colored coating layer 50, and then an intermediate coating is applied on the surface of the uncured colored coating layer 50 by the intermediate coating device 6a. The intermediate coating film layer 40 is formed by wet application. The film thickness after baking hardening of the intermediate coating layer 40 formed in the intermediate coating step 6 is, for example, 15 to 45 μm, and is after baking baking of the colored coating layer 50 as in the first embodiment. The film thickness is, for example, 3 to 45 μm.

  In the coating material for forming the colored coating layer 50, as a coloring material, an existing coloring material having an average particle diameter exceeding 1 μm and, for example, atomization coloring in which an average particle diameter obtained by refining an existing coloring material is 30 nm to 1 μm. The material is added. On the other hand, the fine coating material is not added to the intermediate coating material according to the present embodiment, and only a normal coloring material having an average particle diameter exceeding 1 μm is added.

  In the present embodiment, in addition to the existing colorant, this atomized colorant is formed by forming a colored coating layer 50 containing a fine particle colorant on the surface of the electrodeposition coating layer 20. Therefore, it is possible to reduce the round of the electrodeposition coating layer 20 and improve the smoothness of the surface of the multilayer coating 10. It is practically difficult to make the average particle diameter of the atomized colorant smaller than 30 nm. Further, if the average particle diameter exceeds 1 μm, it becomes too large relative to the existing colorant particles and cannot fill the colorant particles, and the surface of the multilayer coating film 10a is smooth. May not be improved.

  The atomized colorant contained in the colored coating layer 50 according to the present embodiment has a glass transition point Tg higher than the baking temperature of the colored coating layer 50, specifically, 100 ° C to 180 ° C. Glass transition point Tg.

  In the present embodiment, the fine colorant contained in the colored coating layer 50 has a glass transition point Tg of 100 ° C. to 180 ° C., so that the atomized coloring material is baked when the colored coating layer 50 is baked. Since the space between the particles of the existing colorant is surely filled without being thermally deformed, the smoothness of the surface of the laminated coating film 10a is further improved.

  Examples of the additive added to the paint forming the colored coating layer 50 include waxes such as polyethylene wax and polypropylene wax, dispersants, etc., and examples of the solvent include water or aromatic carbonization. Examples thereof include hydrogen solvents or hydrocarbon solvents (ester solvents, ketone solvents, alcohol solvents, etc.).

  After the intermediate coating film layer 40 is formed and flashed off by the intermediate coating flash-off device 6b, the intermediate coating film layer 40 is carried out to the top coating base coating process 7, and thereafter, as in the first embodiment, the top coating base coating film process. 7, the topcoat base coating is applied wet-on-wet to the surface of the uncured intermediate coating layer 40 to form a topcoat base coating layer 70. In the topcoat clear coating step 8, an uncured topcoat base is formed. The top coat clear paint is applied wet-on-wet to the surface of the coat layer 70 to form a clear top coat film 80, and in the middle top coat baking step 9, the colored coat layer 50, the intermediate coat film layer 40, and the top coat The base coating layer 70 and the overcoat clear coating layer 80 are baked and cured simultaneously. Therefore, in the coating method according to the present embodiment, 4 coats and 1 bake are given in regard to the intermediate top coat system.

  As described above, in the coating method according to the present embodiment, in addition to the existing coloring material, the colored coating layer containing the atomized coloring material having an average particle diameter of 30 nm to 1 μm is added to the undercoat coating layer and the intermediate coating. By forming it between the coating layer, this atomized coloring material fills the space between the existing coloring materials, reduces the round of the undercoat coating layer, and improves the smoothness of the surface of the laminated coating Therefore, it is possible to realize a wet-on-wet coating system of intermediate coating and top coating while maintaining the sharpness. As a result, a drying furnace for intermediate coating, which has been conventionally required, becomes unnecessary, and the process space of the coating line is significantly reduced. Further, since the heat energy used in the drying furnace is not necessary, the production cost can be reduced.

  In the coating method according to the present embodiment, the atomized colorant contained in the colored coating layer has a glass transition point Tg of 100 ° C. to 180 ° C., so that the colored coating layer is baked. Since the atomized colorant sometimes reliably fills the space between the existing colorant particles without thermal deformation, the smoothness of the surface of the laminated coating film can be further improved.

[Third Embodiment]
FIG. 5 is a sectional view showing a laminated coating film according to the third embodiment of the present invention.

  As shown in FIG. 5, the laminated coating film 10 b according to this embodiment includes an electrodeposition coating layer 20 formed on the surface of the automobile body B, and an intermediate coating formed on the surface of the electrodeposition coating layer 20. The coating layer 40, the colored coating layer 50 formed on the surface of the intermediate coating layer 40, the top coating base coating layer 70 formed on the surface of the coloring coating layer 50, and the top coating base coating It consists of an overcoat clear coating layer 80 formed on the surface of the film layer 70.

  The laminated coating film 10b according to the present embodiment has an intermediate coating film layer 30 containing a fine colorant in addition to the existing coloring material in the laminated coating film 10 according to the first embodiment shown in FIG. As shown in FIG. 4, the intermediate coating film layer 40 does not contain the atomized colorant, and the existing colorant and atomization are further formed between the intermediate coating film layer 40 and the topcoat base coating film layer 70. A colored coating layer 50 containing a colorant is laminated, and more coating layers are laminated than the laminated coating layer 10 according to the first embodiment, and the colored coating layer according to the second embodiment shown in FIG. The stacking order of the layer 50 and the intermediate coating layer 40 is changed. In addition, since the electrodeposition coating film layer 20, the top coat base coating film layer 70, and the top coating clear coating film layer 80 are the same as those in the first embodiment, their detailed description is omitted.

  The intermediate coating film layer 40 of the laminated coating film 10b according to the present embodiment is formed in the intermediate coating process 6 in FIG. 1, and the colored coating film layer 50 is formed in the top coating base coating process 7 in FIG. The

  In the intermediate coating process 6 according to this embodiment, after the electrodeposition coating layer 20 is baked and cured in the undercoat baking process 4, the intermediate coating apparatus 6a is applied to the surface of the cured electrodeposition coating layer 20 by intermediate coating. The intermediate coating film layer 40 is formed by applying a coating material, and after the intermediate coating flash-off device 6b flashes off the intermediate coating film layer 40, the intermediate coating film layer 40 is overcoated without being baked and cured. Carry out to base coating process 7. In addition, the intermediate coating material which forms this intermediate coating film layer 40 is the same coating material as in the second embodiment. Moreover, the film thickness after baking hardening of the intermediate coating film layer 40 formed in the intermediate coating step 6 is, for example, 15 to 45 μm as in the second embodiment.

  And in the top coat base coating process 7, first, the heat formed by adding a colorant or an additive to the polyester resin, acrylic resin, polyvinyl acetate vinyl copolymer resin, urethane resin, cellulose resin or the like as a main component. A curable coating, a room temperature curable coating, or a two-component curable coating diluted with a solvent is applied to the surface of the uncured intermediate coating layer 40 by the top coat base coating device 7a, and the colored coating layer 50 is formed, and then the top coat base coating is applied on the surface of the uncured colored coating film layer 50 by wet-on-wetting by the top coat base coating device 7a to form the top coat base coating layer 70. In addition, the film thickness after baking hardening of the colored coating film layer 50 formed at the top coat base coating process 7 is, for example, 3 to 45 μm as in the second embodiment.

  In the coating material for forming the colored coating layer 50, as a coloring material, an existing coloring material having an average particle diameter exceeding 1 μm and, for example, atomization coloring in which an average particle diameter obtained by refining an existing coloring material is 30 nm to 1 μm. The material is added.

  In the present embodiment, in addition to the existing coloring material, by forming the colored coating layer 50 containing the fine particle coloring material on the surface of the intermediate coating layer 40, the atomized coloring material is Since the space between the particles of the existing colorant in the colored coating layer is filled, the rounding of the electrodeposition coating layer 20 and the intermediate coating layer 40 can be reduced, and the smoothness of the surface of the laminated coating layer 10 can be improved. It becomes possible. It is practically difficult to make the average particle diameter of the atomized colorant smaller than 30 nm. Further, if the average particle diameter exceeds 1 μm, it becomes too large relative to the existing colorant particles, and cannot fill between the colorant particles, and the surface of the multilayer coating film 10b is smooth. May not be improved.

  Further, the atomized colorant contained in the colored coating layer 50 according to the present embodiment has a glass transition point Tg higher than the baking temperature of the colored coating layer 50, specifically, 100 ° C. to It has a glass transition point Tg of 180 ° C.

  In the present embodiment, the fine colorant contained in the colored coating layer 50 has a glass transition point Tg of 100 ° C. to 180 ° C., so that the atomized coloring material is baked when the colored coating layer 50 is baked. Since the space between the particles of the existing colorant is surely filled without being thermally deformed, the smoothness of the surface of the laminated coating film 10b is further improved.

  Examples of the additive added to the paint forming the colored coating layer 50 include waxes such as polyethylene wax and polypropylene wax, dispersants, etc., and examples of the solvent include water or aromatic carbonization. Examples thereof include hydrogen solvents or hydrocarbon solvents (ester solvents, ketone solvents, alcohol solvents, etc.).

  After the top coat base coating layer 70 is formed and flashed off by the top coat base flash-off device 7b, it is transported to the top coat clear coating process 8, and thereafter the top coat clear coating process 8 as in the first embodiment. Thus, the top coat clear paint is applied wet-on-wet on the surface of the uncured top coat base coat layer 70 to form a top coat clear coat layer 80. The colored coating layer 50, the top coating base coating layer 70, and the top coating clear coating layer 80 are simultaneously baked and cured. Therefore, in the coating method according to the present embodiment, 4 coats and 1 bake are given in regard to the intermediate top coat system.

  As described above, in the coating method according to the present embodiment, in addition to the existing coloring material, a colored coating layer containing an atomized coloring material having an average particle diameter of 30 nm to 1 μm is coated with an intermediate coating layer. By forming it between the base coating layer, this atomized colorant fills the space between the existing colorant particles, reducing the round of the undercoat layer and intermediate coating layer, Since the smoothness of the surface is improved, it is possible to realize a wet-on-wet coating system of intermediate coating and top coating while maintaining sharpness. As a result, a drying furnace for intermediate coating, which has been conventionally required, becomes unnecessary, and the process space of the coating line is significantly reduced. Further, since the heat energy used in the drying furnace is not necessary, the production cost can be reduced.

  In the coating method according to the present embodiment, the atomized colorant contained in the colored coating layer has a glass transition point Tg of 100 ° C. to 180 ° C., so that the colored coating layer is baked. Since the atomized colorant sometimes reliably fills the space between the existing colorant particles without thermal deformation, the smoothness of the surface of the laminated coating film can be further improved.

[Fourth Embodiment]
FIG. 6 is a sectional view showing a laminated coating film according to the fourth embodiment of the present invention.

  As shown in FIG. 6, the laminated coating film 10 c according to this embodiment includes an electrodeposition coating layer 20 formed on the surface of the automobile body B and a colored coating formed on the surface of the electrodeposition coating layer 20. A film layer 50; an intermediate coating layer 30 formed on the surface of the colored coating layer 50; an overcoat base coating layer 70 formed on the surface of the intermediate coating layer 30; It consists of an overcoat clear coating layer 80 formed on the surface of the film layer 70.

  The laminated coating film 10c according to this embodiment does not contain the atomized colorant of the laminated coating film 10a according to the second embodiment shown in FIG. Is the same as the laminated coating film 10a according to the second embodiment except that the intermediate coating film layer 30 containing the existing coloring material and atomized coloring material is changed. In the intermediate coating process 6, unlike the manufacturing method according to the second embodiment, in addition to the existing colorant exceeding 1 μm, atomization with an average particle diameter of 30 nm to 1 μm and a glass transition point Tg of 100 ° C. to 180 ° C. An intermediate coating containing a colorant is applied.

  Thus, in addition to the existing colorant, the atomized colorant having an average particle diameter of 30 nm to 1 μm is contained in the intermediate coating layer, and in addition to the existing colorant, the average particle diameter is 30 nm to 1 μm. By forming a colored coating layer containing the finely divided coloring material between the undercoat coating layer and the intermediate coating layer, the fine particle coloring material fills the particles of the existing coloring material, and the undercoat coating is applied. Since the roundness of the film layer and intermediate coating layer is reduced and the smoothness of the surface of the laminated coating is improved, a wet-on-wet coating system with intermediate coating and top coating is maintained while maintaining the sharpness. It can be realized. As a result, a drying furnace for intermediate coating, which has been conventionally required, becomes unnecessary, and the process space of the coating line is significantly reduced. Further, since the heat energy used in the drying furnace is not necessary, the production cost can be reduced.

  In the coating method according to the present embodiment, the atomized colorant contained in the colored coating layer has a glass transition point Tg of 100 ° C. to 180 ° C., so that the colored coating layer is baked. Since the atomized colorant reliably fills the space between the existing colorant particles without being thermally deformed, the smoothness of the surface of the laminated coating film can be further improved.

[Fifth Embodiment]
FIG. 7 is a sectional view showing a laminated coating film according to the fifth embodiment of the present invention.

  As shown in FIG. 7, the laminated coating film 10 d according to this embodiment includes an electrodeposition coating layer 20 formed on the surface of the automobile body B, and an intermediate coating formed on the surface of the electrodeposition coating layer 20. The coating layer 30, the colored coating layer 50 formed on the surface of the intermediate coating layer 30, the top coating base coating layer 70 formed on the surface of the coloring coating layer 50, and the top coating base coating It consists of an overcoat clear coating layer 80 formed on the surface of the film layer 70.

  The laminated coating film 10d according to the present embodiment includes an intermediate coating film layer 40 that does not contain the atomized coloring material of the laminated coating film 10b according to the third embodiment and contains only the existing coloring material. Except for the change to the intermediate coating film layer 30 containing the coloring material and the atomized coloring material, it is the same as the laminated coating film 10b according to the third embodiment, and the intermediate coating process 6 of the coating method according to this embodiment. Then, unlike the manufacturing method according to the third embodiment, in addition to the existing colorant exceeding 1 μm, it contains an atomized colorant having an average particle diameter of 30 nm to 1 μm and a glass transition point Tg of 100 ° C. to 180 ° C. An intermediate coating is applied.

  Thus, in addition to the existing colorant, the atomized colorant having an average particle size of 30 nm to 1 μm is contained in the intermediate coating layer, and in addition to the existing colorant, the average particle is 30 nm to 1 μm. By forming a colored coating layer containing atomized coloring material between the intermediate coating layer and the top coating base coating layer, this atomized coloring material fills the particles of the existing coloring material and undercoats. Since the roundness of the coating layer and intermediate coating layer is reduced and the smoothness of the surface of the laminated coating layer is improved, wet-on-wet coating system with intermediate coating and top coating while maintaining sharpness Can be realized. As a result, a drying furnace for intermediate coating, which has been conventionally required, becomes unnecessary, and the process space of the coating line is significantly reduced. Further, since the heat energy used in the drying furnace is not necessary, the production cost can be reduced.

  In the coating method according to the present embodiment, the atomized colorant contained in the colored coating layer has a glass transition point Tg of 100 ° C. to 180 ° C., so that the colored coating layer is baked. Since the atomized colorant reliably fills the space between the existing colorant particles without being thermally deformed, the smoothness of the surface of the laminated coating film can be further improved.

[Sixth Embodiment]
FIG. 8 is a sectional view showing a laminated coating film according to the sixth embodiment of the present invention.

  As shown in FIG. 8, the laminated coating film 10 e according to this embodiment includes an electrodeposition coating layer 20 formed on the surface of the automobile body B, and a colored coating formed on the surface of the electrodeposition coating layer 20. A film layer 50, an intermediate coating layer 30 formed on the surface of the colored coating layer 50, a colored coating layer 60 formed on the surface of the intermediate coating layer 30, and the colored coating layer The top coat base coating layer 70 formed on the surface 60 and the top clear coating layer 80 formed on the surface of the top coat base layer 70 are configured.

  The laminated coating film 10e according to the present embodiment is added to the existing colorant between the intermediate coating film layer 30 and the top coating base coating film layer 70 according to the fourth embodiment shown in FIG. The colored coating layer 60 containing the atomized colorant is laminated, and more coating layers are laminated than the laminated coating layer 10c according to the fourth embodiment. In addition, since the electrodeposition coating film layer 20, the top coat base coating film layer 70, and the top coating clear coating film layer 80 are the same as those in the first embodiment, their detailed description is omitted.

  The colored coating layer 50 and the intermediate coating layer 30 of the laminated coating layer 10e according to this embodiment are formed in the intermediate coating step 6 in FIG. 1 and are formed on the surface of the intermediate coating layer 30. The colored coating layer 60 is formed in the top coat base coating step 7 of FIG.

  In the intermediate coating process 6 according to the present embodiment, after the electrodeposition coating layer 20 is baked and cured in the undercoat baking process 4, first, a polyester resin, an acrylic resin, a polyvinyl chloride vinyl chloride copolymer resin, a urethane resin, A thermosetting paint or a room temperature curable paint or a two-component curable paint prepared by adding a colorant or an additive to cellulose resin or the like as a main component is diluted with a solvent by an intermediate coating apparatus 6a. The colored coating layer 50 is formed on the surface of the electrodeposition coating layer 20, and then the intermediate coating material is wet-on-wet by the intermediate coating device 6a on the surface of the uncured colored coating layer 50. After the intermediate coating film layer 30 is formed by application and flashed off by the intermediate coating flash-off device 6b, the colored coating film layer 50 and the intermediate coating film layer 30 are baked and cured. Rather, it is carried out to the base top coating step 7. The film thickness after baking and curing of the intermediate coating film layer 30 formed in the intermediate coating film process 6 is, for example, 15 to 45 μm, and the baking coating and curing of the colored coating film layer 50 as in the first embodiment. The subsequent film thickness is, for example, 3 to 45 μm.

  In the top coat base coating step 7, first, a paint similar to the paint on which the colored paint film layer 50 is formed is applied to the surface of the uncured intermediate coat film layer 30 by the top coat base coating device 7a. Then, the colored coating layer 60 is formed, and then the top coating base coating is applied wet-on-wet to the surface of the uncured colored coating layer 60 by the top coating base coating device 7a. Is formed. In addition, the film thickness after baking hardening of the colored coating film layer 60 formed in the top coat base coating process 7 is, for example, 3 to 45 μm as in the second embodiment.

  In the coating method according to the present embodiment, the coating film and the intermediate coating composition that form the colored coating layer 50 applied in the intermediate coating step 6 described above, and the colored coating layer applied in the top coating base coating step 7 In the coating material forming 60, as a coloring material, an existing coloring material having an average particle diameter exceeding 1 μm and, for example, an atomized coloring material having an average particle diameter of 30 nm to 1 μm obtained by refining an existing coloring material, respectively. It has been added.

  In the present embodiment, the atomized colorant is added to the intermediate coating layer 30 in addition to the existing colorant, and the colored coating layers 50 and 60 containing the atomized colorant in addition to the existing colorant are included. By forming it in the upper layer and the lower layer of the intermediate coating layer 30, the atomized coloring material contained in these coating layers 30, 50, 60 fills the particles of the existing coloring material, and the electrodeposition coating The round of the layer 20 and the intermediate coating layer 30 can be reduced, and the smoothness of the surface of the laminated coating layer 10e can be improved. Note that it is practically difficult to reduce the average particle diameter of these atomized coloring materials to be smaller than 30 nm. Further, if the average particle diameter exceeds 1 μm, it becomes too large relative to the existing colorant particles, so that the space between the colorant particles cannot be filled, and the surface of the multilayer coating film 10e is smooth. May not be improved.

  The atomized colorant contained in the intermediate coating layer 30 and the colored coating layers 50 and 60 according to this embodiment is a glass having a temperature higher than the baking temperature of the intermediate coating layer 30 and the colored coating layers 50 and 60. It has a transition point Tg. Specifically, it has a glass transition point Tg of 100 ° C. to 180 ° C.

  In the present embodiment, the atomized colorant contained in the intermediate coating film layer 30 and the colored coating film layers 50 and 60 has a glass transition point Tg of 100 ° C. to 180 ° C. When the film layer 30 and the colored coating layers 50 and 60 are baked, the atomized coloring material is surely filled between the particles of the existing coloring material without being thermally deformed, thereby further improving the smoothness of the surface of the laminated coating film 10e. To do.

  Examples of the additive added to the paint forming the colored coating layers 50 and 60 include waxes such as polyethylene wax and polypropylene wax, dispersants, etc., and the solvent is water or Aromatic hydrocarbon solvents or hydrocarbon solvents (ester solvents, ketone solvents, alcohol solvents, etc.) can be exemplified.

  After the top coat base coating layer 70 is formed and flashed off by the top coat base flash-off device 7b, it is transported to the top coat clear coating process 8, and thereafter the top coat clear coating process 8 as in the first embodiment. Then, the top coat clear coating is applied wet-on-wet on the surface of the uncured top coat base coating layer 70 to form a top coating clear coating layer 80. The intermediate coating layer 40, the colored coating layer 60, the top coating base coating layer 70, and the top coating clear coating layer 80 are simultaneously baked and cured. Therefore, in the coating method according to the present embodiment, 5 coats and 1 bake are mentioned in regard to the intermediate top coat system.

  As described above, in the coating method according to the present embodiment, in addition to the existing colorant, an atomized colorant having an average particle diameter of 30 nm to 1 μm is contained in the intermediate coating film layer, and the existing colorant is added. In addition, by forming a colored coating layer containing an atomized coloring material having an average particle size of 30 nm to 1 μm on the upper and lower layers of the intermediate coating layer, these atomized coloring materials are formed between the particles of the existing coloring material. To improve the smoothness of the surface of the laminated coating layer by reducing the rounds of the undercoat layer and intermediate coating layer, so that the intermediate coating and top coating can be maintained while maintaining the sharpness. A wet-on-wet coating system can be realized. This eliminates the need for an intermediate coating drying furnace that has been conventionally required, and significantly reduces the process space of the coating line. Further, since the heat energy used in the drying furnace is not necessary, the production cost can be reduced.

  Moreover, in the coating method which concerns on this embodiment, since the atomization coloring material contained in an intermediate coating film layer and a colored coating film layer has the glass transition point Tg of 100 to 180 degreeC, the said coloring Since the atomized colorant is surely filled between the particles of the existing colorant without being thermally deformed when the coating layer is baked, the smoothness of the surface of the laminated coating can be further improved.

[Seventh Embodiment]
FIG. 9 is a sectional view showing a laminated coating film according to the seventh embodiment of the present invention.

  As shown in FIG. 9, the laminated coating film 10 f according to this embodiment includes an electrodeposition coating layer 20 formed on the surface of the automobile body B and an intermediate coating formed on the surface of the electrodeposition coating layer 20. From the coating layer 30 ′, the top coating base coating layer 70 formed on the surface of the intermediate coating layer 30 ′, and the clear top coating layer 80 formed on the surface of the top coating base coating layer 80. It is configured.

  The laminated coating film 10f according to the present embodiment has an intermediate coating film layer 30 ′ containing an atomized coloring material having an average particle diameter of 30 nm to 1 μm in addition to an existing coloring material having an average particle diameter exceeding 1 μm. The configuration is the same as that of the laminated coating film 10 according to the first embodiment shown in FIG.

  For the intermediate coating film layer 30 ′ of the laminated coating film 10f according to the present embodiment, a bright material 90 such as aluminum flakes or mica flakes having an average particle diameter of 1 to 20 μm and a thickness of 0.01 to 0.5 μm. However, it is contained in an amount of 1 to 20% by weight, more preferably 1 to 10% by weight, based on the resin solid content of the intermediate coating layer 30 ′. If the weight ratio of the bright material 90 exceeds 20% by weight, the coating film adhesion may be adversely affected. In addition, the weight ratio here means the weight B of the glittering material with respect to the resin solid content weight A, that is, B / A [%].

  In the coating method according to this embodiment, in addition to the existing colorant, the atomized colorant having an average particle diameter of 30 nm to 1 μm is contained in the intermediate coating film layer, so that the atomized colorant is already colored. Fills between the particles of the material, reduces the round of the undercoat layer and intermediate coat layer, and improves the smoothness of the surface of the laminated coating layer, so that the intermediate coating and top coating while maintaining the sharpness It becomes possible to realize a wet-on-wet coating system with coating. As a result, a drying furnace for intermediate coating, which has been conventionally required, becomes unnecessary, and the process space of the coating line is significantly reduced. Further, since the heat energy used in the drying furnace is not necessary, the production cost can be reduced.

  In the coating method according to the present embodiment, the atomized colorant contained in the intermediate coating has a glass transition point Tg of 100 ° C. to 180 ° C., so that the intermediate coating layer is baked. Since the atomized colorant reliably fills the space between the existing colorant particles without being thermally deformed, the smoothness of the surface of the laminated coating film can be further improved.

  Further, when the top coating material is a metallic coating material, the top coating base coating layer also includes a glittering material (not shown). Therefore, in the coating method according to this embodiment, the top coating base coating layer includes Interference of reflected light occurs between the glitter material contained and the glitter material contained in the above-mentioned intermediate coating layer, and a metallic feeling different from the case where the glitter material is contained only in the top coat base paint can be obtained. .

[Eighth Embodiment]
FIG. 10 is a cross-sectional view showing a laminated coating film according to the eighth embodiment of the present invention.

  As shown in FIG. 10, the laminated coating film 10 g according to this embodiment includes an electrodeposition coating layer 20 formed on the surface of the automobile body B, and an intermediate coating formed on the surface of the electrodeposition coating layer 20. A coating layer 40 ′, a colored coating layer 50 formed on the surface of the intermediate coating layer 40 ′, a top coating base coating layer 70 formed on the surface of the colored coating layer 50, and the top coating The top coating clear coating layer 80 is formed on the surface of the base coating layer 70.

  The laminated coating film 10g according to the present embodiment does not contain an atomized colorant having an average particle diameter of 30 nm to 1 μm as a colorant, and contains only an existing colorant having an average particle diameter exceeding 1 μm. The intermediate coating film layer 40 ′ has the same configuration as that of the multilayer coating film 10b according to the third embodiment shown in FIG.

  In the intermediate coating film layer 40 ′ of the laminated coating film 10g according to the present embodiment, a bright material 90 such as aluminum flakes or mica flakes having an average particle diameter of 1 to 20 μm and a thickness of 0.01 to 0.5 μm. However, it is contained in an amount of 1 to 20% by weight, more preferably 1 to 10% by weight, based on the resin solid content of the intermediate coating layer 40 ′. If the weight ratio of the bright material 90 exceeds 20% by weight, the coating film adhesion may be adversely affected.

  In the coating method according to the present embodiment, in addition to the existing coloring material, a colored coating layer containing an atomized coloring material having an average particle diameter of 30 nm to 1 μm is divided into an intermediate coating layer and a top coating base coating layer. By forming between these particles, the atomized colorant fills the particles of the existing colorant, reduces the round of the undercoat layer and the intermediate coat layer, and improves the smoothness of the surface of the laminated coating layer. As a result, it is possible to realize a wet-on-wet coating system of intermediate coating and top coating while maintaining the sharpness. As a result, a drying furnace for intermediate coating, which has been conventionally required, becomes unnecessary, and the process space of the coating line is significantly reduced. Further, since the heat energy used in the drying furnace is not necessary, the production cost can be reduced.

  Moreover, in the coating method which concerns on this embodiment, when the atomization coloring material contained in a colored coating-film layer has the glass transition point Tg of 100 to 180 degreeC, at the time of baking of an intermediate coating film layer Since the atomized colorant reliably fills the space between the existing colorant particles without being thermally deformed, the smoothness of the surface of the laminated coating film can be further improved.

  Further, when the top coating material is a metallic coating material, the top coating base coating layer also includes a glittering material (not shown). Therefore, in the coating method according to this embodiment, the top coating base coating layer includes Interference of reflected light occurs between the glitter material contained and the glitter material contained in the above-mentioned intermediate coating layer, and a metallic feeling different from the case where the glitter material is contained only in the top coat base paint can be obtained. .

  The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, in the above-described embodiment, the intermediate coating film layer and the top coating base coating layer have been described as being flashed off immediately after the formation, but the present invention is not particularly limited thereto. The topcoat base coating film layer may be formed without flashing off immediately after forming and / or the topcoat clear coating film layer may be formed without flashing off immediately after forming the topcoat base coating film layer.

  Hereinafter, the effects of the present invention were confirmed by examples and comparative examples that further embody the present invention. The following examples are for confirming the effects of the coating method according to the above-described embodiment.

Example 1
A dull steel plate having a thickness of 0.8 mm and a size of 70 mm × 150 mm is used as an object to be coated, and a zinc phosphate coating is formed on this by applying a zinc phosphate coating. U-600M) was used for electrodeposition coating so that the film thickness became 20 μm, and an electrodeposition coating layer was formed by baking and curing at 160 ° C. for 30 minutes.

100 parts by weight of acrylic resin (Acridic manufactured by Dainippon Ink and Chemicals), 10 parts by weight of orange pigment (Permanent Orange 3RTN manufactured by Clariant), 5 parts by weight of dispersant (Floren G-700 manufactured by Kyoei Chemical Co., Ltd.) After mixing 230 parts by weight of ethyl acetate, for 3 hours dispersed by addition of alumina beads of particle size 1mm of 350 parts by weight mixer (Tokushu Kika Kogyo Co., Ltd. TK auto homo mixer), an average particle diameter of 30 An atomized colorant (orange) having a nm and a glass transition point Tg of 180 ° C. was obtained.

  The atomized colorant is added to an intermediate coating (High Epico QX1 manufactured by Nippon Oil & Fats Co., Ltd.) so that the weight ratio to the resin solid content is 4% by weight, and an orange pigment having an average particle diameter of 5000 nm (Permanent Orange manufactured by Clariant). 3RTN) is added to the intermediate coating material at a weight ratio of 1% by weight based on the resin solid content, and a bright material (aluminum base manufactured by Nippon B Chemical Co., Ltd.) having an average particle diameter of 15 μm and a thickness of 0.1 μm A coating obtained by adding the coating material at a weight ratio of 1% by weight to the resin solid content and diluting with a thinner (T-536MB, manufactured by Nippon B Chemical Co., Ltd.) as a solvent is 20 to 40 μm in dry film thickness. As described above, the surface of the electrodeposition coating layer was spray-coated to form an intermediate coating layer.

  On the surface of the uncured intermediate coating film layer, a top coat base paint (acrylic / melamine resin manufactured by Nippon Bee Chemical Co., Ltd.) is spray-coated wet-on-wet so that the dry film thickness is 5 to 45 μm, A top coat base coating layer was formed.

Furthermore, the surface of this uncured topcoat base coating layer is spray-coated with a topcoat clear paint (2K clear manufactured by Nippon Bee Chemical Co., Ltd.) wet-on-wet so that the dry film thickness is 30 to 45 μm. A clear coating layer was formed, and these intermediate coating layer, top coating base coating layer, and top coating clear coating layer were simultaneously baked and cured at 140 ° C. for 30 minutes. Table 1 shows the production conditions of the test piece produced in Example 1.

  About the obtained multilayer coating film, the smoothness was evaluated visually, and “○” was defined as having improved smoothness compared to the multilayer coating film of Comparative Example 1 described later, and an improvement in smoothness was observed. Those that do not have an "x".

Moreover, about the obtained laminated coating film, the adhesive test (crosscut method) of JISK5600-5-6 is implemented, and the state of the surface of the crosscut part which has peeled is classified into the classification | category 0-1. The film was evaluated as “◯”, the one classified as classification 2 as “Δ”, and the classification classified as classification 3 to 5 as “×”. The evaluation results are shown in Table 2.

Example 2
A test piece was produced under the same conditions as in Example 1 except that the average particle size of the atomized colorant contained in the intermediate coating was 150 nm. Table 1 shows the production conditions of the test piece produced in Example 2. The test piece produced in Example 2 was evaluated for smoothness and adhesion similar to Example 1. The evaluation results are shown in Table 2.

Example 3
A test piece was produced under the same conditions as in Example 1 except that the average particle size of the atomized colorant contained in the intermediate coating was 1000 nm. Table 1 shows the production conditions of the test piece produced in Example 3. The same smoothness and adhesion as in Example 1 were evaluated for the test piece produced in Example 3. The evaluation results are shown in Table 2.

Example 4
A test piece was produced under the same conditions as in Example 2 except that the glass transition point Tg of the atomized colorant contained in the intermediate coating was 100 ° C. Table 1 shows the production conditions of the test piece produced in Example 4. The same smoothness and adhesion as in Example 1 were evaluated on the test piece produced in Example 4. The evaluation results are shown in Table 2.

Example 5
A test piece was produced under the same conditions as in Example 2 except that the intermediate coating material did not contain a glittering material. Table 1 shows the production conditions of the test piece produced in Example 5. The same smoothness and adhesion as in Example 1 were evaluated on the test piece produced in Example 5. The evaluation results are shown in Table 2.

Comparative Example 1
A test piece was produced under the same conditions as in Example 1 except that the intermediate coating material did not contain the atomized colorant and the glitter material. Table 1 shows the production conditions of the test piece produced in Comparative Example 1. The test piece produced in Comparative Example 1 was evaluated for smoothness and adhesion similar to Example 1. The evaluation results are shown in Table 2.

Comparative Example 2
A test piece was produced under the same conditions as in Example 1 except that the average particle size of the atomized colorant contained in the intermediate coating was 1500 nm. Table 1 shows the production conditions of the test piece produced in Comparative Example 2. The test piece produced in Comparative Example 2 was evaluated for smoothness and adhesion similar to Example 1. The evaluation results are shown in Table 2.

Comparative Example 3
A test piece was produced under the same conditions as in Example 2 except that the amount of glittering material contained in the intermediate coating was 25% by weight. Table 1 shows the production conditions of the test piece produced in Comparative Example 3. The same smoothness and adhesion as in Example 1 were evaluated for the test piece produced in Comparative Example 3. The evaluation results are shown in Table 2.

Comparative Example 4
A test piece was produced under the same conditions as in Example 1 except that the intermediate coating material did not contain the existing colorant and atomized colorant. Table 1 shows the production conditions of the test piece produced in Comparative Example 4. The same smoothness and adhesion as in Example 1 were evaluated on the test piece produced in Comparative Example 4. The evaluation results are shown in Table 2.

Consideration From Examples 1 to 5 and Comparative Example 1, the smoothness of the surface of the laminated coating film was improved by including the atomized colorant in the intermediate coating in addition to the existing colorant. Further, from Examples 1 to 5 and Comparative Example 4, even when only the glittering material was added to the intermediate coating without adding the atomized colorant, the smoothness of the surface of the laminated coating film was not improved. .

  From Examples 1 to 3 and Comparative Example 2, in addition to the existing colorant, the smoothness of the surface of the laminated coating film was improved by containing the atomized colorant of 30 nm to 1 μm.

  From Example 2 and Comparative Example 3, when the addition amount of the glittering material was 20% by weight or more based on the resin solid content of the intermediate coating material, the adhesion of the laminated coating film deteriorated.

FIG. 1 is a process diagram showing a coating method according to the first embodiment of the present invention. FIG. 2 is a plan view showing an example of a line in the middle top coating process of FIG. FIG. 3 is a cross-sectional view showing the laminated coating film according to the first embodiment of the present invention. FIG. 4 is a cross-sectional view showing a laminated coating film according to the second embodiment of the present invention. FIG. 5 is a cross-sectional view showing a laminated coating film according to the third embodiment of the present invention. FIG. 6 is a cross-sectional view showing a laminated coating film according to the fourth embodiment of the present invention. FIG. 7 is a cross-sectional view showing a laminated coating film according to the fifth embodiment of the present invention. FIG. 8 is a cross-sectional view showing a laminated coating film according to the sixth embodiment of the present invention. FIG. 9 is a cross-sectional view showing a laminated coating film according to the seventh embodiment of the present invention. FIG. 10 is a cross-sectional view showing a laminated coating film according to the eighth embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pre-treatment process 2 ... Electrodeposition coating process 3 ... Electrode water washing process 4 ... Undercoat baking process 5 ... Middle topcoat painting process 6 ... Middle coat painting process 7 ... Topcoat base painting process 8 ... Topcoat clear painting process 9 ... Middle topcoat Baking process 10, 10a to 10g ... Laminated coating film 20 ... Electrodeposition coating layer 30, 30 ', 40, 40' ... Intermediate coating layer 50, 60 ... Colored coating layer 70 ... Top coating base coating layer 80 ... Top clear film layer 90 ... Bright material B ... Auto body (Coating object)

Claims (13)

After the undercoat paint is applied to the object to be coated to form the undercoat film layer, the intermediate coat film is formed by applying the intermediate coat paint to the undercoat film layer, and the uncured intermediate coat film layer is formed. A top coating film is applied to form a top coating film layer, and the coating film layer is further baked simultaneously with the coating film layer above the under coating film layer,
A first resin containing at least an upper layer above the undercoat coating layer and colored resin particles having an average particle size of 30 nm to 1 μm and a glass transition point higher than the baking temperature, and a colorant having an average particle size of more than 1 μm. A coating method for forming a colored coating layer. The coating method according to claim 1, wherein the colored resin particles and the colorant have the same color. Said first colored coating layer, a method of coating according to claim 1 or 2, wherein said intermediate coating layer. Said first colored coating layer, a method of coating according to claim 1 or 2, wherein formed between the top coating layer and the intermediate coating layer. It said first colored coating layer, said undercoating film layer and the method of coating according to claim 1 or 2, wherein formed between the intermediate coating layer. At least a second colored coating layer comprising colored resin particles having an average particle size of 30 nm to 1 μm and having a glass transition point higher than the baking temperature, and a colorant having an average particle size of more than 1 μm The coating method according to any one of claims 1 to 5 , further formed in an upper layer than the film layer. The coating method according to claim 6, wherein the second colored coating film layer is formed between the undercoat coating film layer and the intermediate coating film layer. The coating method according to claim 6, wherein the second colored coating film layer is formed between the intermediate coating film layer and the top coating film layer. A third colored coating film layer containing colored resin particles having an average particle diameter of 30 nm to 1 μm and having a glass transition point higher than the baking temperature, and a colorant having an average particle diameter exceeding 1 μm is used as the undercoat coating film. The coating method according to claim 8 , further formed between a layer and the intermediate coating layer. The coating method according to any one of claims 1 to 9 , wherein a glass transition point Tg of the colored resin particles is 100 ° C to 180 ° C. The coating method according to claim 3 or 4 , wherein the intermediate coating film layer contains a bright material. The bright material has an average particle diameter of 1 to 20 µm, a thickness of 0.01 to 0.5 µm, and is contained in an amount of 1 to 20% by weight based on the resin solid content of the intermediate coating layer. 11. The coating method according to 11 . The topcoat includes a topcoat base paint and a topcoat clear paint,
The top coating base coating layer is formed by applying the top coating base coating to the uncured intermediate coating layer, and the top clear coating is further applied to the uncured top coating base coating layer. the method of coating according to any one of claims 1 to 12 forming a membrane layer.

Images