JPH0566192B2 - - Google Patents

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention provides a method for forming coating films with different appearances on the surface of an object to be coated, that is, a smooth coating film and a rough coating film, in one coating line. The present invention relates to a coating film forming method and a forming apparatus used for this purpose.

(Prior Art) Conventionally, as a method for forming a coating film on the surface of an object to be coated, for example, a method of applying a thermosetting resin paint using a halogenated hydrocarbon as a solvent to the surface of the object to be coated, and then drying and curing the coating. There is a method of forming a smooth, glossy, smooth coating film with a desired color on the surface of the object by pre-containing an appropriate pigment in the thermosetting resin coating. There is.

In addition, as a coating film forming method developed by the applicant, after applying a thermosetting resin coating to the surface of the object to be coated,
The uncured coating film on the surface of the object to be coated is dried and cured in a heated acidic gas atmosphere, or the uncured coating film is brought into contact with a heated acidic gas and then dried and cured. By pre-containing an appropriate pigment in the mold resin paint,
There is a method of forming a rough coating film having a desired color in the form of chilimen patterns on the surface of an object to be coated.

(Problems to be Solved by the Invention) However, in such conventional coating film forming methods, there are cases in which a smooth, glossy and smooth coating film is formed on the surface of the object to be coated, and cases in which a smooth coating film is formed on the surface of the object to be coated. Separate coating lines were used for forming rough surface coatings, which resulted in problems such as considerably poor equipment efficiency and an increase in coating costs.

The present invention was made by focusing on such conventional problems, and it is possible to create a smooth, glossy coating film on the surface of the object to be coated, and a rough surface with a chilimen pattern etc. in one painting line. It is an object of the present invention to provide a coating film forming method and a coating film forming apparatus that can form both coating films.

[Structure of the Invention] (Means for Solving the Problems) The method for forming a coating film according to the present invention is to apply a thermosetting resin paint to an object to be coated which has been drained and dried in a drain drying oven, and to a smooth coating film forming step of drying and curing an uncured coating film applied to an object to form a smooth coating film, and applying a thermosetting resin paint to the object to be coated which has been drained and dried in the draining drying oven; The atmosphere in the drain drying oven is changed to an acidic gas atmosphere that contacts the uncured coating film applied to the object to be coated and promotes surface hardening of the uncured coating film, and then reprocessed in the drain drying oven and then dried and hardened. The present invention is characterized in that the rough surface coating film forming step of forming a rough surface coating film is selectively carried out in one coating line.

Further, the coating film forming apparatus directly used for implementing the coating film forming method according to the present invention includes a drain drying oven for draining and drying the coated object before coating, and a thermosetting type for drying the coated object after draining and drying. It is equipped with a coating treatment device that applies a resin paint, and a baking drying oven that dries and hardens the uncured coating film applied to the object to be coated, and the drain drying oven is provided with an acid gas supply means to create an acidic gas atmosphere inside the oven. It is characterized by being able to be formed.

The paint used in the present invention is a thermosetting resin paint, and for example, general thermosetting resin paints such as acrylic resin paint, polyester resin paint, acrylic-melamine resin paint, and epoxy resin paint can be used. It is.

Furthermore, the color of the coating film can be arbitrarily selected by adding an appropriate pigment to the above-mentioned thermosetting resin coating. For example, inorganic pigments such as carbon black, lithopone, lead white, yellow iron oxide, Zinc white, yellow lead, titanium oxide, red bean oxide, etc. can be used alone or in combination. It is also possible to use organic pigments. In addition, by adding an inorganic pigment to the paint, it is possible to reliably form a rough coating film such as a chilimen pattern, and also to make a beautiful and uniform pattern appear.

Furthermore, water-soluble or solvent-based dip coating methods, electrodeposition coating methods, electrostatic coating methods, etc. are adopted as methods for applying thermosetting resin paints, and when solvents are used, halogenated hydrocarbon-based materials are used. , such as trichlorethylene, perchlorethylene, and other conventionally known solvents of this type.

Therefore, in the method for forming a coating film according to the present invention, the above-mentioned thermosetting resin paint is applied to the object to be coated which has been drained and dried in a drain drying oven, and then the uncured coating applied to the surface of the object to be coated is applied. The coating may or may not be reprocessed in the draining/drying oven, which has an atmosphere of acidic gas (including oxidizing gas) that contacts the film and promotes surface hardening of the uncured coating film.

That is, in order to form a smooth and glossy coating film, as shown in the examples below, the acidic gas is brought into contact with the coating film after it has started curing, or the acidic gas is Allow to dry and cure as is without contacting the uncured coating surface.

On the other hand, when it is desired to form a rough coating film with a chilimen pattern, the acidic gas is brought into contact with the surface of the uncured coating film, and the acidic gas is dried and cured after this contact or in the contact atmosphere. In this way, when the surface of an uncured coating film is brought into contact with an acidic gas (for example, sulfur dioxide gas, carbon dioxide gas, hydrogen chloride gas), the gas component acts on the surface of the uncured coating film, causing the surface portion to harden from the inside. Prioritization causes distortion in the paint film, resulting in chilimen pattern (crystalline, vein-like, shallow crack-like, etc.)
Including patterns such as wrinkles. ) etc., a rough coating film is formed. After the coating film surface has started to harden, even if heated acidic gas is brought into contact with it, it is no longer possible to form a chili-like pattern; on the contrary, the coating film surface cannot be cured in an acidic gas atmosphere. If a difference in curing occurs between the surface and the inside of the coating film, a chili-men-like pattern will be formed even if baking drying is performed in a normal atmosphere. varies depending on the components, hardness (viscosity), heating conditions, etc. of the uncured coating film.

As described above, in the method for forming a coating film according to the present invention, by controlling the contact/non-contact of acidic gas and oxidizing gas to the surface of the uncured coating film, smooth and glossy coating can be achieved in one coating line. It is possible to form a smooth coating film or a rough coating film with varying degrees of chilimen pattern.

In addition, the frequency of control of contact/non-contact with the acidic gas, that is, the frequency of whether or not to reprocess in the draining and drying process in an acidic gas atmosphere, depends on the difference in demand for smooth coatings and rough coatings. When the demand for one coating film becomes considerably greater than the demand for the other coating film, switching between contact and non-contact acid gas in the same coating line becomes less frequent, for example, In an actual coating line, it is possible to select a process in which one coating film is formed for 8 to 10 days, and select a process in which the other coating film is formed for 1 to 2 days.

FIG. 1 shows a coating film forming apparatus according to one embodiment of the present invention, and the coating line shown in FIG. 1 includes a pretreatment device 1, an anodization treatment device 2,
It is equipped with a hot water washing device 3, a drain drying oven 4, an immersion coating processing device 5 having a resin bath, and a baking drying oven 7, and the oven having a heated acidic gas atmosphere is the drain drying oven. 4 is used for both purposes. Therefore, after washing with hot water, draining and drying, and painting, the material is charged again into the draining and drying furnace 4 and, if necessary, brought into contact with acidic gas, and then baked and hardened in the baking and drying furnace 7.

The draining drying oven 4 used in this case doubles as an acid gas atmosphere furnace, so for example, it is a draining drying oven with a direct heating drying structure as shown in Fig. 2. When forming a surface coating film, the circulating air in the draining and drying oven 4 is made to pass through the reflux pipe 42, so that acidic gas such as hydrogen chloride gas thermally decomposed by the heat source 41 is supplied into the oven. In order to form a smooth, glossy pattern, the reflux pipe 42 is shut off to prevent generation of acidic gas such as hydrogen chloride gas, or the reprocessing in the draining and drying oven 4 is omitted.

(Example 1) In this Example 1, the draining drying furnace 4 is a direct heating drying furnace that directly heats the circulating airflow in the furnace with a flame, and the baking drying furnace 7 heats the circulating airflow in the furnace by 1.
A painting line was used, which was an indirect heating drying oven that heated using a heat exchanger with a heat medium inlet temperature of 450°C on the next side. After pretreatment in pretreatment device 1, the aluminum alloy A6063S-T5 material on which an anodized film was formed by a conventional method in anodization treatment device 2 was transferred to hot water washing device 3, where it was washed in hot water at 70°C for 20 minutes. After that, dry at 150℃ for 5 minutes in the above-mentioned drain drying oven 4.
After draining and drying for 70 minutes, the paint treatment device 5 was placed in a black acrylic-melamine resin bath (solid content concentration 30%, pigment concentration 15%) containing trichlorethylene as a solvent and Bone Black as a pigment. It was immersed for 3 minutes at ℃, and then pulled up at a lifting speed of 1.2 m/min. Next, the aluminum alloy A6063S-T5 material after dip coating was transferred to the baking drying oven 7 mentioned above and baked at 190°C for 30 minutes, resulting in a smooth and glossy black coating with a coating thickness of 25 μm. A film was formed.

Using the same painting line, aluminum alloy A6063S was pretreated in pretreatment device 1 and then anodized film was formed in anodization treatment device 2 by a conventional method.
- After the T5 material was subjected to hot water washing treatment, drain drying and dip painting treatment under the same conditions as above, this aluminum alloy A6063S-T5 material was placed in the above drain drying oven again.
The paint film was transferred to the baking drying oven 7 and baked for 30 minutes at 190°C to start curing the surface of the coating film. A black coating film having a thickness of 25 μm and having a uniform chilimen pattern was formed over the entire surface.

(Example 2) In this Example 2, the draining drying furnace 4 is a direct heating drying furnace that directly heats the circulating airflow in the furnace with a flame, and the baking drying furnace 7 heats the circulating airflow in the furnace by 1.
A painting line was used, which was an indirect heating drying oven that heated using a heat exchanger with a heat medium inlet temperature of 480°C on the next side. After pretreatment in pretreatment device 1, the aluminum alloy A6063S-T5 material, on which an anodic oxide film was formed by a conventional method in anodization treatment device 2, was transferred to hot water washing device 3, where it was washed in hot water at 90°C for 5 minutes. After that, dry at 160℃ in the drain drying oven 4 mentioned above.
After draining and drying for 15 minutes, the paint treatment equipment 5 has a white acrylic-melamine resin bath (solid content concentration 40%, pigment concentration 40%) containing perchlorethylene as a solvent and titanium oxide as a pigment. for 3 minutes at 70°C, then increase the pulling speed
It was pulled up at a rate of 1.8m/min. Next, the aluminum alloy A6063S-T5 material after dip coating was transferred to the baking drying oven 7 mentioned above and baked at 190℃ for 30 minutes, resulting in a smooth and glossy white coating with a coating thickness of 25 μm. was formed.

Using the same painting line, aluminum alloy A6063S-T5 was pretreated in pretreatment device 1 and then anodized film was formed in anodization device 2 by a conventional method.
After the material was washed with hot water, drained and dried under the same conditions as above, and coated with dip coating, this aluminum alloy
The A6063S-T5 material is again transported to the above-mentioned drain drying oven 4 and heat treated at 160°C for 5 minutes to start curing the coating film surface, and then the above-mentioned baking drying oven 7
When the film was transferred to a vacuum cleaner and baked and dried at 190°C for 30 minutes, a white paint film with a thickness of 20 μm and a uniform chilimen pattern was formed over the entire surface.

[Effects of the Invention] As explained above, in the method for forming a coating film according to the present invention, a thermosetting resin paint is applied to an object to be coated which has been drained and dried in a drain drying oven, and the coating is applied to the object to be coated. A smooth coating film forming step of drying and curing the uncured coating film to form a smooth coating film, and applying a thermosetting resin paint to the coated object that has been drained and dried in the draining drying oven, The atmosphere in the furnace is changed to an acidic gas atmosphere that contacts the uncured coating film applied to the object to be coated and promotes surface hardening of the uncured coating film, and is reprocessed in the drain drying oven and then dried and hardened to form a rough surface. The method is characterized in that the step of forming a rough surface coating film for forming a coating film is selectively carried out in one coating line. The device includes a drain drying oven that drains and dries the object to be coated before painting, a coating treatment device that applies a thermosetting resin paint to the object that has been drained and dried, and an uncured paint applied to the object to be coated. The structure is equipped with a baking drying oven for drying and curing the coating film, and the drying oven is equipped with acidic gas supply means to create an acidic gas atmosphere inside the oven, so that one coating line can coat the surface of the object to be coated. It is possible to form both a smooth and glossy coating film and a rough coating film with a chilimen pattern, and the degree of roughness such as a chilimen pattern can be easily adjusted. This has the remarkable effect of making it possible to perform coating film formation work extremely efficiently.In addition, the acid gas atmosphere furnace is configured to double as a draining and drying furnace. Both smooth and rough coating films can be selectively formed without the need for a separate coating, and even if the object to be coated comes into contact with acidic gas before coating, the appearance of the coating will not be adversely affected. When forming , it is not necessary to discharge acidic gas, there is no need to change the process, and the productivity is extremely improved, which is a very excellent effect.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the configuration of a coating film forming apparatus according to an embodiment of the present invention, and FIG. 2 is a plan explanatory diagram showing the configuration of a draining drying furnace which also serves as an acid gas atmosphere furnace. 4... Draining drying oven, 5... Paint processing equipment, 7... Baking drying oven.

Claims (1)

[Claims] 1. A thermosetting resin paint is applied to an object that has been drained and dried in a drain drying oven, and the uncured coating film applied to the object is dried and cured to form a smooth coating film. a step of forming a smooth coating film, and applying a thermosetting resin paint to the coated object that has been drained and dried in the drain drying oven, and changing the atmosphere in the drain drying oven to the uncured coating applied to the coated object. a rough coating film forming step of forming a rough coating film by reprocessing in the drain drying oven as an acidic gas atmosphere that contacts the film and promotes surface hardening of the uncured coating film, and then drying and curing it; A method for forming a coating film, which is selectively carried out on two coating lines. 2. A drain drying oven for draining and drying the object to be coated before painting, a coating treatment device for applying a thermosetting resin paint to the object to be coated after draining and drying, and an uncured coating film applied to the object to be coated. 1. An apparatus for forming a coating film, comprising: a baking drying oven for drying and curing the coating film, and the draining drying oven is provided with an acidic gas supply means so that an acidic gas atmosphere can be formed inside the oven.