JP2686888B2 - Painted steel plate manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating equipment for coated steel sheets which is extremely beautiful over a wide range of coating thicknesses from thin to thick.

[0002]

2. Description of the Related Art Conventionally, a roll coater in which several rolls are combined has been used as a method for coating the surface of a steel sheet. In the production of these roll-coated steel sheets, various studies have been made on the second and subsequent coating methods relating to the direct appearance characteristics. -8
A roller curtain coater as shown in Japanese Patent No. 0877 has been developed and the appearance characteristics have been improved. As a three-roll coater, for example, as shown in Japanese Patent Laid-Open No. 60-56553, a coating roll on a pickup roll is used which is composed of a pickup roll for drawing up the paint and an applicator roll (also called coating roll) for coating the paint on a steel plate. What consists of a doctor roll for scraping (commonly called V type 3 roll coater) can be used.

Further, as disclosed in Japanese Patent Application Laid-Open No. 63-4869, in order to manufacture a strip-shaped steel sheet having a good surface appearance, an abricator roll and a pick-up roll of a three-roll coater are used as rubber lining rolls. The transfer roll in the middle is a steel roll, the surface hardness of the rubber lining roll and the contact roll advancing direction of the pickup roll and the transfer roll are the same direction, and the roll contact advancing direction of the transfer roll and the applicator roll is the same direction. Further, by adjusting the material of the roll lining, the contact propelling direction and the peripheral speed so that the peripheral speed of the applicator roll is higher than the peripheral speed of the transfer roll, it is possible to obtain a good appearance.

A schematic view of the roller curtain coater is shown in FIG. By supplying the paint of the paint reservoir 15 whose viscosity has been adjusted in advance to the roll gap between the paint roll 9 and the doctor roll 10 made of metal, the paint roll rotation direction 11 and the doctor roll 10 rotation direction 13 cause rotation. It is discharged and scraped by the blade 12 which is in contact with the coating roll 9. The scraped paint flows down along the blade 12 to form a paint curtain 14, which is applied to the steel plate 1 as an object to be coated passing below the blade 12 to form a coating film 16. The doctor roll 10 can be moved back and forth with respect to the coating roll 9, and the doctor roll 10 can be displaced to adjust the roll gap between the two rolls. A predetermined coating film thickness can be obtained by adjusting the roll gap, the plate passing speed, and the peripheral speeds of the coating roll 9 and the doctor roll 10.

[0005]

As described above, although some measures have been taken to obtain the appearance coatability of the coated surface, a three-roll coater such as that disclosed in JP-A-60-56553. Even in the so-called V-type three-roll coater, and also in the three-roll coater as disclosed in Japanese Patent Laid-Open No. 63-4869, it is possible to obtain a coated steel sheet with a small coating thickness and a good coating appearance by coating with a thin coating thickness. However, as the thickness of the coating film increases, roping tends to occur, and it becomes difficult to obtain a good appearance even if the material of the roll and the peripheral speed are adjusted.

On the other hand, in the roller curtain coater as disclosed in Japanese Patent Laid-Open No. 63-80877, the paint reservoir 15
Is supplied to the roll gap between the coating roll 9 and the doctor roll 10 made of metal, and is discharged by the rotation of the coating roll 9 in the rotation direction 11 of the coating roll and the rotation direction 13 of the doctor roll 10. Scraped with the blade 12 in contact, the scraped paint is the blade 1
The paint curtain 14 is formed by flowing down along the line 2, but since the paint curtain 14 is formed into a film by the surface tension of the paint itself, the thicker it is, the more stable it is to obtain a coated steel sheet with a good coating appearance. However, it becomes unstable as the thickness decreases, and eventually the film breaks, which makes painting difficult. As described above, it is difficult to obtain a good appearance in a wide range of coating thicknesses from thin coating thickness to thick coating coating by using either a three-roll coater or a roller curtain coater.

[0007]

[Means for Solving the Problems] As a result of intensive studies, the inventors of the present invention should solve the above problems, and as a result, the appearance is extremely beautiful in a wide range of coating thicknesses from thin to thick. (1) In a facility for manufacturing a coated steel sheet by coating and baking at least once on the back surface and twice or more on the front surface , the first coating device is provided. 2 roll coater, 3
It has at least one of a roll coater or roller curtain coater, and is thin as a coating device for the second and subsequent surfaces.
A coated steel sheet manufacturing facility having both a three-roll coater for a film and a roller curtain coater for a thick film, and having a two-roll coater or a three-roll coater as a second or subsequent coating device on the back surface. (2) A carriage for moving the roller curtain coater as the second or subsequent coating device on the front surface to the outside of the line is arranged, and a steel plate for a two-roll coater or a three-roll coater as the second or subsequent coating device on the back surface. In the coated steel sheet manufacturing facility described in (1) above, a roll elevating device for changing the pass line for increasing the winding angle is provided.

[0008]

The present invention will be described below in detail. FIG. 1 is an example of a conceptual diagram of a coated steel sheet manufacturing facility embodying the present invention. In the pretreatment device 2 of the steel plate 1, the zinc plated steel plate which has been subjected to various pretreatments such as degreasing cleaning and chromate coating is subjected to the undercoating of the front surface by the two-roll coater by the first coating device 3 of the surface and the first coating device of the back surface. The underside is coated with a 2-roll coater by No. 4 and baked by the first baking device 5. After that, when the thickness of the second coating film on the front surface is thick, the coating device 6c or 6d is used to top-coat the surface with the roller curtain coater, and subsequently the back surface second coating device 7 is used with the two-roll coater, if necessary. After performing the above, baking is performed by the second baking device 8 and
Layer coating is performed. When the thickness of the second coating film on the front surface is thin, the coating device 6a or 6b is used to top coat the surface with a three-roll coater, and subsequently, if necessary, the second coating device 7 on the back surface is coated with a two-roll coater. After performing the above, baking is performed by the second baking device 8 and
Layer coating is performed.

FIG. 2 is another example of a conceptual view of a coated steel sheet manufacturing facility embodying the present invention. Normally, the pass line changing roll 17 is raised to the upper limit and coating is performed in the same manner as the above example. In addition, the double-coated double-sided coated steel sheet has a thin coating film thickness and the steel sheet 1 has a small thickness, and the second roll coating device 7 of the back surface has a small wrapping angle of the steel sheet around the coating roll of the two-roll coater and presses it against the coating roll. When the pressure becomes small and the coating becomes unstable, first move the roller curtain coaters of the second surface coating devices 6c and 6d to the outside of the line, then lower the pass line changing roll 17 to the lower limit to change the pass line. (Dotted line), the wrapping angle of the steel plate around the coating roll of the two-roll coater of the second coating device 7 on the back side can be increased, the pressing pressure on the coating roll can be increased, and the coating can be stabilized to obtain a beautiful coating appearance. Became.

[0010]

[Example] Plate thickness 0.4 to 0.45 mm, plate width 600 mm
On the electro-galvanized steel sheet of No. 1, a surface polyester resin-based undercoating was applied at the first time to a coating film thickness of 5 μm, and a polyester resin-based topcoating to a coating film thickness of 8 μm and 20 μm at the second time, respectively. Table 1 shows the results. According to Table 1, in the present invention, the coating thickness of 8 μm is 3 roll coater, the coating thickness is 20 μm.
m is produced in a roller curtain coater, both roping, repelling, good coated steel plate is small paint defects called dents is obtained. On the other hand, in the conventional example, when the coating thickness is 20 μm, defects such as roping, cissing, and dents occur when the coating thickness is 20 μm, and when the coating thickness is 8 μm, coating defects occur due to the paint curtain breaking when the coating thickness is 20 μm. There is.

[0011]

[Table 1]

[0012]

As described above, in comparison with the conventional roll coater and roller curtain coater alone, a coated steel sheet having a beautiful appearance can be obtained over a wide range of coating thicknesses from thin to thick. Became possible.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of an example of a coated steel sheet facility according to the present invention,

FIG. 2 is a conceptual diagram of another example of coated steel sheet equipment according to the present invention,

FIG. 3 It is a schematic diagram of a conventional roller curtain coater.
You.

 ─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-4-61960 (JP, A) JP-A-4-222663 (JP, A) JP-A-3-12258 (JP, A) JP-A-63- 80877 (JP, A) Actual flat 3-38185 (JP, U) Actual flat 1-122879 (JP, U)

Claims (2)

(57) [Claims] 1. In a facility for producing a coated steel sheet by coating and baking at least once on the back surface and twice or more on the front surface , a two-roll coater, a three-roll coater or a roller curtain is used as the first coating device. at least one of the coaters has both 3-roll coater and roller curtain coater for thick film for a thin film as a second or subsequent coating device surfaces, two-roll coater as the second and subsequent coating device of the back Alternatively, a coated steel sheet manufacturing facility having a 3-roll coater. 2. A transfer carriage for moving a roller curtain coater as a second or subsequent coating device on the front surface to the outside of the line is provided, and to a two-roll coater or a three-roll coater as a second or subsequent coating device on the back surface. 2. The coated steel sheet manufacturing equipment according to claim 1, further comprising a roll elevating device for changing a pass line for increasing a winding angle of the steel sheet.