JP2757759B2 - Coating method by roll coater - 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 method using a roll coater for performing high-speed and beautiful continuous coating on a strip material by roll coating in an equipment line such as a surface-treated steel sheet.

[0002]

2. Description of the Related Art A roll coater type coating apparatus (hereinafter referred to as a roll coating apparatus) has been widely used for continuous coating on a belt-like material such as a running steel sheet. The roll coating apparatus includes a natural coater system in which the rotation direction of the applicator roll is the same as the traveling direction of the strip material, and a reverse coater system in which the rotation direction of the applicator roll is opposite to the traveling direction of the strip material. The natural coater method is suitable for thin film coating and is used for primer coating. The reverse coater method has good uniformity of a coating film and is used for a top coat.

[0003] In recent years, pre-coated steel sheets which are applied to a material before forming and assembling are processed and assembled as they are, and a chemical conversion treatment, coating and baking process by a user can be omitted. It has good paint use efficiency and baking energy efficiency, has high resource and energy saving effects, and is widely used for home appliances, automobiles and the like.
Hot-dip galvanized steel sheet,
Applying resin or paint using roll coating, curtain flow coating or electrostatic coating to enhance the function of surface-treated steel sheets such as electro-galvanized steel sheets, cold-rolled steel sheets, and chrome-coated steel sheets. , Enhances lubricity. In most cases, coil painting is roll painting.

Generally, when applying resin to the front and back surfaces of a surface-treated steel sheet, as shown in FIG.
1 attaches the coating liquid in the coating liquid pan 42 to the outer periphery, transfers the coating liquid to an applicator roll 43 to have a predetermined thickness, and then applies the coating liquid to the surface of the workpiece 45 moving along the backup roll 44. After the coating film is formed by continuous transfer from the tar roll 43, the material 45 to be coated is lifted by the lift roll 46.
The warp deformation is removed, and the pickup roll 47 causes the coating liquid in the coating liquid pan 48 to adhere to the outer periphery, transfers the coating liquid to the applicator roll 49 to a predetermined film thickness, and then moves the coating target material 45. The coating film is formed by continuous transfer from the applicator roll 49 to the back surface.

On the other hand, when coating a cold-rolled steel sheet or a plated steel sheet with a resin or paint, it is preferable to install a roll coating apparatus in the plating line from the viewpoint of manufacturing cost, but the roll coating apparatus is installed in the existing plating line. Incorporation of the roll coating apparatus requires a large space remodeling, so that the installed roll coating apparatus is preferably space-saving. The roll coating apparatus of space-saving, as shown in FIG. 5, the pickup roller 51 to adhere the coating liquid coating solution pan 52 to the outer periphery, which was transferred to the applicator roll 53 through a transfer roll 54 After a predetermined thickness is formed, a coating film is continuously transferred from the applicator roll 53 to the surface of the moving workpiece 55 to form a coating film. The roll 57 causes the coating liquid in the coating liquid pan 58 to adhere to the outer periphery, and this is applied to the applicator roll 5.
9, the coating material 55 that moves after being transferred to a predetermined thickness.
An I-type roll coating apparatus without a backup roll, which continuously transfers a coating film from an applicator roll 59 to the back surface of a sheet, is known, and is mainly used for coating a thin plate.

[0006] Further, as an improvement of the roll coating apparatus shown in FIG. 4, the roll height can be adjusted in the direction of lifting the steel strip between the front surface coating portion and the back applicator roll. A coating apparatus in which a lift roll having a diameter equal to or greater than a predetermined value of the thickness of the belt is disposed as close as possible to the back applicator roll (Japanese Patent Laid-Open No. 63-1119).
No. 59) has been proposed.

[0007]

Since the I-type roll coating apparatus shown in FIG. 5 has no backup roll, the steel strip abuts on the surface applicator roll only by tension and passes therethrough. It will pass by contacting the backside applicator roll. Therefore, I
Die roll coating equipment is susceptible to warpage of the steel strip, etc., and it is necessary to correct the warpage of the steel strip by using a lift roll. There is a disadvantage that it is difficult to install a lift roll corresponding to a thick one. Further, since the apparatus disclosed in Japanese Patent Application Laid-Open No. 63-111959 has a backup roll and a lift roll, the equipment itself becomes large and cannot be installed in an existing plating line.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a coating method using a roll coater which can solve the drawbacks of the above-mentioned I-type roll coating apparatus and can perform beautiful coating on the front and back surfaces of a steel strip without using a lift roll. It is in.

[0009]

Means for Solving the Problems The present inventors have conducted various tests and studies to achieve the above object. As a result, the axial distance between the front applicator roll and the back applicator roll is set to a predetermined value, and the occurrence of unpainted or thin film areas at the edge due to the warpage of the steel strip caused by the front applicator roll is reduced. The inventors of the present invention have found that the intermeshing amount between the applicator roll and the backside applicator roll can be prevented by setting the intermesh amount to a predetermined value according to the plate thickness, and reached the present invention.

That is, the present invention relates to a method for continuously coating the front and back surfaces of a steel strip by using an I-type roll coating apparatus having no lift roll, wherein the distance between the axes of the front applicator roll and the back applicator roll is 10 to 100.
mm, and the amount of intermesh between the front applicator roll and the back applicator roll is set in inverse proportion to the plate thickness.

[0011]

According to the present invention, as shown in FIG. 6, a front applicator roll 61 and a rear applicator roll 62 are used.
When the distance L between the shafts is set to 10 to 100 mm, the steel strip 63 is warped by the front applicator roll 61, so that the edge of the steel strip 63 is uncoated or coated on the back applicator roll 62. A thin region occurs. In order to prevent such an uncoated or thin film region at the edge portion of the steel strip 63, it is effective to increase the inter-mesh amount IM between the front applicator roll 61 and the back applicator roll 62. However, if the intermesh amount IM is too large, the surface pressure between the applicator roll and the steel strip increases, causing problems such as seizure of the applicator roll or motor trip of the applicator roll. In particular, since this tendency is more remarkable as the plate thickness increases, it is important to set an appropriate center distance between the front applicator roll and the back applicator roll. Therefore, in the present invention, the center distance L between the front-side applicator roll and the back-side applicator roll is set to 10 to 100.
mm, and the in-mesh amount I is inversely proportional to the plate thickness.
By setting M, uniform and beautiful coating can be performed over a wide range of plate thicknesses.

The optimum value of the inter-mesh amount between the front-side applicator roll and the back-side applicator roll is stored in a large number of operation data in the past, among which uneven coating after coating, motor load of the applicator roll, and applicator roll. Evaluate from the occurrence of roll seizure, store the conditions with good results in advance as sheet thickness by multiple regression equation, etc., and input the sheet thickness of the next steel strip in advance to calculate the intermesh amount. It can be set automatically. According to experiments performed by the present inventors, the front and back applicator roll diameter was 450 mm, and the center distance between the front and back applicator rolls was 4 mm.
The relationship between the plate thickness and the inter-mesh amount IM under the condition of 0 mm was almost inversely proportional to the plate thickness, as shown in FIG.

[0013]

EXAMPLE 1 As shown in FIG. 1, as a top applicator roll 1 and a back applicator roll 2, a steel roll having a diameter of 430 mm and a rubber lining having a thickness of 20 mm were provided. 300 mm steel roll, upper and lower pickup rolls 5 and 6 with a diameter of 3
The peripheral speed of the upper and lower pickup rolls 5 and 6 was set to 0.3 in a ratio to the line speed of 50 m / min using a roll coating device including a 00 mm steel roll and paint pans 7 and 8. The peripheral velocities of the rolls 1 and 2 and the upper and lower transfer rolls 3 and 4 were both set to 1.5 in terms of the ratio to the line speed. Then, for a plated steel strip 9 having a plate thickness of 3.2 mm and a plate width of 1220 mm, an axial distance L between the front applicator roll 1 and the back applicator roll 2 is determined.
And the accuracy of the inter-mesh amount IM (plate thickness -1 mm) between the front applicator roll 1 and the back applicator roll 2 using a screw bar is ± 0.5 m.
m, and a chromate solution was applied .

After baking the obtained steel strips coated with the chromate solution, the amount of chromium adhering to the edge portions was measured. FIG. 2 shows the relationship between the axial distance between the front applicator roll 1 and the back applicator roll 2 and the amount of edge chrome adhesion. As is clear from FIG. 2, when the axial distance between the front-side applicator roll 1 and the back-side applicator roll 2 is less than 10 mm, the front-back applicator roll 1,
2 was tripped, and stable application was impossible.
When the axial distance between the front applicator roll 1 and the back applicator roll 2 exceeds 100 mm, an uncoated portion occurs on the back edge of the plated steel strip 9. On the other hand, in the range where the axial distance between the front-side applicator roll 1 and the back-side applicator roll 2 is 10 to 100 mm, the edge chromium adhesion amount is stable at 20 to 25 mg / m ² .

[0015]

As described above, according to the method of the present invention, the axial distance between the upper and lower applicator rolls is set to 10 to 100 mm and the interface between the upper and lower applicator rolls is set. By setting the mesh amount in inverse proportion to the plate thickness, it is possible to prevent the edge from being uncoated even if the lift roll is omitted, and it can be installed on an existing plating line due to space saving.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an I-type roll coating apparatus used in Examples.

FIG. 2 is a graph showing a relationship between an axial distance between a front applicator roll and a back applicator roll and an edge chromium adhesion amount.

FIG. 3 is a graph showing a relationship between a plate thickness and an intermesh amount.

FIG. 4 is a schematic explanatory view of a conventional roll coating apparatus.

FIG. 5 is a schematic explanatory view of a conventional I-type roll coating apparatus.

FIG. 6 is a diagram illustrating the principle of an I-type roll coating apparatus according to the present invention.

[Explanation of symbols]

1,61 Front surface applicator roll 2,62 Back surface applicator roll 3 Upper transfer roll 4 Lower transfer roll 5 Upper pickup roll 6 Lower pickup roll 7,8 Paint pan 9 Plated steel strip 63 Steel strip 41,47,51,57 Pickup Rolls 42, 48, 52, 58 Coating pans 43, 49, 53, 59 Applicator rolls 44 Backup rolls 45, 55 Coating materials 46, 56 Lift rolls 54 Transfer rolls L Surface applicator roll and backside applicator roll Distance between axes IM intermesh amount

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-161273 (JP, A) JP-A-54-127935 (JP, A) JP-A-5-265219 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) B05D 1/28 B05D 7/14 B05C 1 / 08,1 / 12

Claims (1)

(57) [Claims] 1. A method for performing continuous coating on the front and back surfaces of a steel strip by using an I-type roll coating apparatus having no lift roll, wherein a distance between axes of a front applicator roll and a back applicator roll is set to 10 to 100 mm. A coating method using a roll coater, wherein the intermesh amounts of the front applicator roll and the back applicator roll are set in inverse proportion to the plate thickness.