JPH07323255A - Continuous coating method for metallic strip - Google Patents

Abstract

PURPOSE:To shorten the time for changing a coating material, reduce coating material loss and obtain a beautiful coating film by reversing the rotating direction of an applicator roll from the progressing direction of a steel strip, etc., and supplying the coating material from a nozzle near a pickup roll or the applicator roll. CONSTITUTION:The rotating direction of the applicator roll 1 is reversed from the progressing direction of the metallic strip S at the contact point with the metallic strip S and the rotating direction of the pickup roll 2 is set in the same direction at the contact point with the applicator roll 1. The desired amt. of the coating material is transferred from above the applicator roll 1 onto the metallic strip S by control of the mounting force or spacing adjustment between the applicator roll 1 and the pickup roll 2 when the coating material P is supplied in this state from the nozzle 9 near the pickup roll 2 onto the pick up roll 2. The spilling coating material is recovered in a trough 8 and is then returned to a coating material tank 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for continuously coating a metal strip such as a steel strip with a roll coater, and more particularly to a method for supplying paint to a roll coater.

[0002]

2. Description of the Related Art Continuous coating of metal strips such as steel strips is widely performed by a roll coater. Generally, as shown in FIG. 3, a part of the coating P is retained in a coating pan 4. The coating material P is scraped up by the pickup roll 2 in which the applicator roll 1 and the pickup roll 2
This is carried out by a method of transferring the paint on the applicator roll 1 to the metal strip S after adjusting the amount of paint to be supplied onto the applicator roll 1 by adjusting the pressing force or the gap therebetween. At this time, the paint P retained in the paint pan 4 is circulated by the paint in the drum can or the paint tank 5 and the pump 6, and the viscosity is adjusted in the drum can or the paint tank 5. In the figure, reference numeral 7 indicates a backup roll that supports the metal strip S during coating.

In such a method, it takes a long time to clean the coater roll, the paint pan, the tank and the paint transfer pipe when the type of paint is changed, and the paint adhered to the inner surface of the pan and the pipe. It is unavoidable that the cost will increase and the cost will increase due to the use of thinner for cleaning. Furthermore, since the upper portion of the paint pan 4 is open, thinner in the paint evaporates while the paint remains,
Viscosity increases and the amount of adhesion changes.

In order to prevent this, it is necessary to frequently adjust the viscosity in the aforementioned paint tank.
As a method for solving these problems, Japanese Unexamined Patent Publication No. 57-135069 discloses a system shown in FIG. 4 and Japanese Patent Publication No. 1-34103 discloses a system shown in FIG. The system of FIG. 4 forms a liquid pool at the contact portion between the applicator roll 1 and the pickup roll 2 and supplies the coating material P to this portion while controlling the supply amount, thereby eliminating the need for a coating material pan and eliminating the need for coating material switching. This is a method to reduce the time and the paint loss. However, in this method, it is necessary to rotate the rolls in the same direction at the contact points of the metal strip S and the applicator roll 1 and between the applicator roll 1 and the pickup roll 2, respectively, and this is generally called roping. It is unavoidable that a pattern is generated on the coating film, and it is difficult to apply it when the surface appearance is demanded.

The system shown in FIG. 5 uses the metering roll 3
A liquid pool is formed by supplying the paint P to the contact portion between the pickup roll 2 and the pickup roll 2, and the metal strip S and the applicator roll 1 and the applicator roll 1 and the pickup roll 2 are both rotated in opposite directions at the contact point. There is no defective appearance due to roping, and the paint pan can be eliminated. However, since three coater rolls are required, the load of roll cleaning becomes large, and roll replacement becomes very poor in workability. In FIGS. 4 and 5, reference numeral 8 indicates a gutter, which returns the paint leaking from the liquid pool to the paint tank 5.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a two-roll roll coater,
A paint pan for supplying paint is not required, paint switching time is shortened, paint loss is reduced, viscosity adjustment frequency is reduced, etc., and a beautiful paint film with no roping in the paint film appearance can be obtained. It is to propose a continuous coating method for metal strips.

[0007]

SUMMARY OF THE INVENTION A first aspect of the present invention is to provide an applicator roll that is continuously coated with a roll coater including an applicator roll that contacts the metal strip and a pickup roll that is connected to the applicator roll. The rotation direction is opposite to the traveling direction of the metal strip at the contact point with the metal strip, and the rotation direction of the pickup roll is the same direction as the traveling direction of the applicator roll at the contact point with the applicator roll. This is a continuous coating method for a metal strip, characterized in that paint is supplied to the pickup roll from a nozzle installed close to the roll.

In the second aspect of the present invention, when a metal strip is continuously coated with a roll coater consisting of an applicator roll that comes into contact with the metal strip and a metering roll that is connected to the applicator roll, the direction of rotation of the applicator roll is changed. It is installed close to the applicator roll, with the direction of travel of the metal strip being the opposite direction at the point of contact with the metal strip, and the direction of rotation of the metering roll being the same or opposite to the direction of rotation of the applicator roll. In this method, the coating is supplied from the nozzle to the applicator roll, and the metering roll is installed downstream of the coating supply position in the rotational direction of the applicator roll.

[0009]

In both the first and second aspects of the present invention,
Since the paint is supplied to the pick-up roll or the nozzle installed in the vicinity of the applicator roll from these nozzles and only two roll coaters are used, the paint pan becomes unnecessary and the paint switching time is shortened. It is possible to reduce loss and frequency of viscosity adjustment.

Further, since the advancing direction of the metal strip and the rotating direction of the applicator roll are opposite to each other, it is possible to obtain a beautiful coating film without roping in the appearance of the coating film.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram schematically showing a first embodiment of the present invention in a two-roll roll coater composed of an applicator roll 1 and a pickup roll 2. Applicator roll 1 to prevent roping, which is a visual defect
The rotation direction of the pickup roll 2 is opposite to the traveling direction of the metal strip S at the contact point with the metal strip S, and the rotation direction of the pickup roll 2 enables film thickness control.
At the contact point with the applicator roll 1, the traveling directions are the same. Pickup roll 2 in this state
The coating material P is supplied onto the pickup roll 2 from the nozzle 9 which is close to. The supplied paint is controlled by adjusting the pressing force or the gap between the applicator roll 1 and the pickup roll 2, and a desired amount of paint is transferred from the applicator roll onto the metal strip S. The paint overflowing during control is collected by the gutter 8 and returned to the paint tank 5. The gap between the pickup roll 2 and the nozzle 9 has an adjustable structure, and the nozzle 9 is preferably a slit nozzle capable of uniformly supplying the coating material in the width direction.

FIG. 2 is a diagram schematically showing a second embodiment of the present invention in a two-roll roll coater composed of an applicator roll 1 and a metering roll 3. In order to prevent roping which is an appearance defect, the rotation direction of the applicator roll 1 is opposite to the traveling direction of the metal strip S at the contact point with the metal strip S,
The rotation direction of the metering roll 3 is the same as that of the applicator roll 1 at the contact point with the applicator roll. In this state, the coating material P is applied onto the applicator roll 1 from the nozzle 9 installed near the applicator roll 1.
Is supplied. The supplied paint is applicator roll 1
The desired amount of paint is transferred from the applicator roll 1 onto the metal strip S, which is controlled by adjusting the pressing force or the gap between the metering roll 3 and the metering roll 3. The paint overflowing during control is collected by the gutter 8 and returned to the paint tank 5. The gap between the applicator roll 1 and the nozzle 9 has an adjustable structure, and the nozzle 9 is preferably a slit nozzle capable of uniformly supplying the paint in the width direction. In FIG. 2, the rotation direction of the metering roll 3 is the same as the traveling direction at the contact point with the applicator roll 1, but it can be reversed (indicated by a broken line in the drawing).

In this way, by setting the rotation direction of the metering roll 3 to be the direction of the broken line in the figure, the traveling direction is made opposite at all contact points of the roll or the metal strip, and the film thickness is controlled. It is also possible to obtain a more beautiful coating film without roping. Although various examples have been described above, any one of them is adopted in consideration of the properties of the coating material (viscosity, concentration, specific gravity, etc.), the coating film thickness, and the degree of beauty required for the appearance of the coating film. You just have to decide.

By the way, using the conventional method shown in FIG. 5 and the method of the present invention shown in FIG. 1, a high-speed polyester coating is applied at a strip speed of 45 mpm and a thickness of 15 μm on a steel strip for a predetermined length. I switched the type. In the conventional method,
The amount of paint used for the same length of steel strip is about 5 compared to the method of the present invention.
% Extra required. Further, in the conventional method, about 8% of cleaning thinner and about 30% extra time for switching are required for cleaning at the time of switching the paint as compared with the method of the present invention.

As for the beauty of the coating, the method of the present invention was not inferior to the conventional method. Similar effects were obtained in the case of the method of the present invention shown in FIG.

[0016]

INDUSTRIAL APPLICABILITY The present invention is a continuous coating method for a metal strip such as a steel strip by a roll coater of two rolls, in which the rotation direction of the applicator roll is opposite to the traveling direction of the steel strip or the like, and a pickup roll or an applicator roll A coating with a beautiful surface can be obtained by supplying paint to the roll with a nozzle and collecting the overflowed paint controlled by the gutter between the pickup roll and the applicator roll or between the applicator roll and the metering roll. At the same time, it is possible to eliminate the need for a paint pan for paint supply, reducing paint loss when switching paints,
The reduction in cleaning thinner was achieved, the load required for cleaning was also reduced, and the time required for switching was shortened. Also,
Compared to the amount of thinner evaporated from the paint pan, the area exposed to the atmosphere was reduced, so the amount of thinner evaporated was reduced and the frequency of viscosity adjustment was also reduced.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an outline of a coating apparatus according to the present invention.

FIG. 2 is a schematic view showing the outline of another coating apparatus according to the present invention.

FIG. 3 is a schematic diagram showing an outline of a conventional coating apparatus.

FIG. 4 is a schematic diagram showing an outline of a conventional coating apparatus.

FIG. 5 is a schematic diagram showing an outline of a conventional coating apparatus.

[Explanation of symbols]

 1 Applicator roll 2 Pickup roll 3 Metering roll 4 Paint pan 5 Paint tank 6 Pump 7 Backup roll 8 Gutter 9 Nozzle S Metal strip P Paint

Claims (2)

[Claims] 1. When continuously coating a metal strip with a roll coater consisting of an applicator roll that is in contact with the metal strip and a pickup roll that is connected to the applicator roll, the direction of rotation of the applicator roll is at the contact point with the metal strip. The direction opposite to the traveling direction of the strip is set, and the rotation direction of the pickup roll is set to the same direction as the traveling direction of the applicator roll at the contact point with the applicator roll. A continuous coating method for a metal strip, which comprises supplying paint to a pickup roll. 2. When continuously coating a metal strip with a roll coater comprising an applicator roll that contacts the metal strip and a metering roll that is connected to the applicator roll, the direction of rotation of the applicator roll is determined at the contact point with the metal strip. The applicator roll is set in a direction opposite to the traveling direction of the metal strip, and the rotation direction of the metering roll is set in the same direction or in the opposite direction to the rotation direction of the applicator roll, and the applicator roll is provided by a nozzle installed close to the applicator roll. A continuous coating method for a metal strip, characterized in that a coating material is supplied to the coating material, and the metering roll is installed on the downstream side in the rotational direction of the applicator roll from the coating material supply position.