JP2846183B2 - Manufacturing method of painted steel sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a coated steel sheet.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 6, a coated steel sheet is subjected to a primer coating on a surface of a steel sheet W by a first coater 23 and then dried and baked by a first oven 24. After that, it is cooled by the first cooling device 25, and subsequently, the undercoating surface is overcoated with the second coater 26 and dried and baked in the second oven 27.
It is manufactured by cooling with the second cooling device 28.
In addition, the back surface of the steel plate W is also the first and second back surface coaters 29, 30.
At least one of them. As described above, conventionally, on the coating surface to be used, undercoating and topcoating are performed, but for each coating, drying and baking are performed in an oven, and cooling is performed by a cooling device. Two units are required, the amount of energy consumption is large, and not only a large space is required, but also there are problems that a large number of workers are required due to the two-tiered coating part. Therefore, an object of the present invention is to provide a method for producing a coated steel sheet which can be made into a coated steel sheet by one drying and baking treatment by devising the above-mentioned undercoating and overcoating methods.

[0003]

According to the present invention, in order to achieve the above object, in producing a coated steel sheet, in the first invention, an undercoat paint is applied to the surface of the steel sheet, and then the undercoat paint is applied to an undried undercoat paint. To the top coat with a die coater,
Thereafter, a backside coating is performed, and the double-sided coated steel sheet is subjected to a dry baking treatment. In the second invention, the undercoating and the topcoating are performed by a two-layer coating die coater.

[0004]

Next, one embodiment of the first invention will be described with reference to FIGS. In the figure, 1 and 2 are backup rolls, 3a and 3b are first and second surface die coaters, 9
Is a back die coater, 12 is an applicator roll, and 20 is
Is a drying and baking apparatus.

As shown in FIG. 2, the first surface die coater 3a comprises a base 4 and a coater main body 6 having a die 7 which moves forward and backward by an actuator 5 attached to the base 4. Backup roll 1 rotatably mounted on a support (not shown) 4
With a predetermined gap. Reference numeral 8 denotes a suction box, and the suction box 8 is provided as needed. Further, the first surface die coater 3a is also used for the backup roll 2.
And a second surface die coater 3b having the same configuration as the above.

On the other hand, as shown in FIG. 3, the back die coater 9 has a first base 10 and a second base having an applicator roll 12 at an end thereof, which is moved forward and backward by an actuator 11 on the first base 10. 13, and a coater main body 15 having a die 16 that moves forward and backward by an actuator 14 attached to the second base 13. The die 16 faces the applicator roll 12 with a predetermined gap. In addition, 17 is a suction box, and this suction box 17 is provided as needed. Reference numeral 18 denotes a stabilizer roll that moves forward and backward on the lower surface of the first base 10 by an actuator 19.

The drying and baking apparatus 20 includes an oven 21
And a cooling device 22, the configuration of which is the same as that of a conventionally known device.

[0008] Because of the above-mentioned configuration, a quick-drying paint such as a paint, Modified epoxy,
An epoxy-based or modified high-molecular polyester-based modified acrylic resin paint is supplied to a predetermined thickness to perform undercoating. Then, by the second surface die coater 3b,
On top of the undried undercoat, an overcoat, for example, a polyester-based, silicone-polyester-based, polymer linear polyester-based, or polyvinyl chloride-based resin paint is supplied to a predetermined thickness to perform the overcoating. .

As described above, a rust-preventive paint, for example, a modified polyester-based, polyester-based, or epoxy-based resin paint is applied from the die 16 to the back surface of the steel plate W whose surface has been undercoated and overcoated via the applicator roll 12. Apply.

[0010] As described above, the steel sheet W applied to both sides is dried and baked on both sides in the oven 21 and cooled by the cooling device 22 to be a product. In the above embodiment, the paint is applied on the steel sheet W by the die coater in both the undercoating and the topcoating, but the undercoating and the backside coating may be performed by a roll coater.

Next, in the second invention, in the first invention, the surface coating is performed with the undercoating and the topcoating using two coating apparatuses. ,
As shown in FIG. 5, surface coating is performed by one two-layer coating die coater 3c. That is, as shown in FIG. 4, the two-layer coating die coater 3c
a, 16b, the undercoat paint is supplied as a thin layer from the die 16a to the surface of the steel body W, and the top coat paint is supplied as a thin layer from the die 16b to the surface of the undercoat paint. The upper and lower paints are applied at one time. The other parts are the same as those of the first invention, and the same parts are denoted by the same reference numerals and description thereof will be omitted.

The heating method of the oven 21 is as follows.
Hot air heating, induction heating, or both may be used.
That is, as shown in Table 1, the coating system and the heating system could take various forms, and good results could be obtained in each case.

[Table 1]

[0013]

As is apparent from the above description, according to the present invention, since the top coat is applied in a non-contact state with a die coater, the top coat is continuously applied even if the undercoat is in an undried state. Can be. Therefore, the front and back painted surfaces can be dried and baked at a time by one dry baking apparatus, and the equipment cost can be reduced accordingly. In addition, since the undercoating machine and the topcoating machine can be arranged at the same level, operation by a small number of people becomes possible.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a coated steel sheet manufacturing apparatus according to a first invention.

FIG. 2 is a schematic front view of the surface die coater of FIG.

FIG. 3 is a schematic front view of the back die coater of FIG. 1;

FIG. 4 is a schematic explanatory view of a coated steel sheet manufacturing apparatus according to a second invention.

FIG. 5 is a schematic front view of a two-layer coating die coater according to the second invention.

FIG. 6 is a schematic view of a conventional coated steel sheet manufacturing apparatus.

[Explanation of symbols]

1, 2, ... backup roll, 3a, 3b ... first, second
Surface die coater, 3c ... two-layer coating surface die coater, 7,
16a, 16b: die, 9: back die coater, 12 ...
Applicator roll, 20: Dry baking device.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B05D 7/14 B05C 5/02 B05D 1/26 F26B 23/08

Claims (2)

(57) [Claims] 1. An undercoat paint is applied to the surface of a steel sheet, an overcoat paint is subsequently applied by a die coater on the undercoat paint in an undried state, and then a back coat is applied, and the double-coated steel sheet is dried and baked. Characteristic method of manufacturing coated steel sheet. 2. A method for producing a coated steel sheet, comprising applying a base coat and a top coat to the surface of a steel sheet using a two-layer coating die coater, then applying a back coating, and drying and baking the double-coated steel sheet. .