JPH0829279B2 - Roll coating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention applies a high-viscosity paint in a thin and uniform thickness on the surface of a thin metal plate such as a thin strip-shaped metal plate or a plate-shaped metal plate used for canned cans. A possible roll coating device.

(Prior Art) As shown in FIG. 4, a conventional roll coating apparatus for coating a thin metal plate used for a can is a backup roll 1 made of an inelastic material such as a metal material, and this backup roll 1 , And the outer peripheral portion for applying the paint to the surface of the belt-shaped metal plate 2 is made of an elastic material A such as a rubber material (hereinafter, the outer peripheral portion of the roll is elastic. The roll made of material is sometimes called a ○○ roll made of elastic material.) The applicator roll 3 and the outer peripheral portion for applying paint to the outer peripheral surface of the applicator roll 3 are made of a non-elastic material such as a metal material. The pick-up roll 4 is provided with a pickup roll 4 (hereinafter, such a roll may be referred to as an inelastic material XX roll) and a paint supply nozzle 8 for supplying the paint 5 to the tray 6. of A part is immersed in the paint 5 in the saucer 6.

 This coating apparatus operates as follows to perform coating.

First, the outer periphery of the applicator roll 3 in which the pick-up roll 4 adheres the paint 5 on the tray 6 to the outer peripheral surface thereof and rotates in the direction of arrow a in FIG. 4, and rotates in the direction of arrow b opposite to the pick-up roll 4. The adhering paint 5a is drawn into the pressure contact point 7 with the surface, and the paint is pressed against the outer peripheral surface of the applicator roll 3 made of an elastic material. When the pickup roll 4 and the applicator roll 3 rotate further, about 1/2 of the drawn paint adheres to the applicator roll 3 as paint 5b, and about 1/2 remains on the pickup roll 4.

When the pressure contact strength of the pressure contact point 7 becomes strong, the pressure contact point 7
The thickness of the paint drawn in to the applicator roll 3 is reduced, and the thickness of the paint 5b attached to the applicator roll 3 is also reduced.

That is, the coating material having a desired thickness can be applied onto the outer peripheral surface of the applicator roll 3 by appropriately adjusting the pressure contact strength.

After that, the applicator roll 3 is further rotated,
The paint 5b on the outer peripheral surface of the applicator roll 3 is transferred to the entire surface of the metal plate 2 so as to come into contact with the metal plate 2 moving in the direction of the arrow c opposite to the direction of the rotation arrow b, and the surface is painted. To be done.

At this time, the backup roll 1 is rotating in the same direction as the metal plate 2.

(Problems to be Solved by the Invention) Using the conventional coating device described above, for example, at a high speed of 100 m / min, a commonly used coating is applied to the surface of the metal plate at 60 to 140 m.
When applied to a thin thickness such as g / Dm ² (coating thickness after drying), there arises a problem that color unevenness becomes noticeable due to swelling of a known applicator roll. Furthermore, the applicator roll 3 and the pickup roll 4 must be rotated at a peripheral speed of 100 m / min. However, when the pick-up roll 4 is rotated at such a high speed, the amount of the paint adhering to the pick-up roll 4 increases more than the ratio of the peripheral speed increase, and the paint is drawn into the pressure contact point 7 between the pick-up roll 4 and the applicator roll 3. Since the amount of paint to be applied increases and the amount of paint 5 on the outer peripheral surface of the applicator roll 3 increases, in order to deliver a desired amount to the applicator roll 3, the pressure contact point 7 between the applicator roll 3 and the pickup roll 4 is strengthened. Alternatively, reduce the solids content of the paint (for example, increase the viscosity of the paint to Ford Cup # 4,25).
It is necessary to make the coating film thick at the time of coating, but thin after drying and baking, by making it as small as 18 to 25 seconds.

However, when the pressure contact is strengthened, the wear of the applicator roll proceeds extremely fast, not only the consumption amount of the solvent increases but also the heat amount required for drying and baking the coating film increases,
In addition, since a large amount of solvent evaporates in the dry baking furnace, there is a drawback that the pollution control device for processing the solvent must be upsized and the cost increases.

In addition to the above, there is a problem in that the paint in the tray is likely to foam due to the high-speed rotation of the pickup roll, and a large amount of the solvent is vaporized during drying and baking, so that bubbles are likely to be generated in the coating film.

It is an object of the present invention to provide a roll coating device that solves the above drawbacks and problems.

(Means for Solving the Problem) The present invention aims to solve the above-mentioned drawbacks and problems, and the applicator roll is made of a specific elastic material such as a metal by using a high-viscosity paint, and even if it is thinly coated, the metal is used. It was made based on the knowledge that the plate is not damaged, and the device of the present invention sandwiches a thin metal plate between a backup roll made of an elastic material and the backup roll, and the thin metal plate in progress An applicator roll made of a non-elastic material for applying the above paint, and a part of the outer peripheral portion is immersed in the paint,
A first roll made of an elastic material that draws paint between the applicator roll and applies the paint to the applicator roll, and is downstream of the first roll in the rotational direction of the applicator roll and more than the backup roll. A roll coating device that is located at an upstream position and that has a second roll made of an inelastic material that limits the thickness of the coating material on the applicator roll between the roll coating device and 1 invention), and in addition to the above configuration, a coating material reservoir for supplying additional coating material to the applicator roll is provided at a position upstream of the second roll and downstream of the first roll, and thin coating is performed at high speed. It is a possible roll coating device (2nd invention).

(Operation) The coating apparatus of the first invention has a role of pressing and adhering the paint to the applicator roll when a part of the stored paint is in contact and rotates.
Since the roll is made of an elastic material, it is possible to cause the high-viscosity paint to adhere to the outer peripheral surface of the roll even at high-speed rotation and to proceed with it. In addition, the second roll made of non-elastic material
Since it is provided on the downstream side of the roll, it is not necessary to limit the amount of coating material at the pressure contact point between the first roll and the applicator roll, and therefore damage to the first roll can be prevented. Also, since the roll made of an elastic material having good wettability with the paint is the first roll,
It is possible to pump up a sufficient amount of paint even at low speed rotation,
Since the speed of the first roll can be set lower than the speed of the applicator roll, it is possible to suppress foaming of the paint in the pan.

The high-viscosity paint transferred from the first roll to the applicator roll has a desired thickness by passing through the gap formed by both the applicator roll and the second roll, and remains on the applicator roll. Then, the high-viscosity paint on the applicator roll forms a thin coating film of uniform thickness on the surface of the metal plate. According to this apparatus, the thin metal plate is not scratched and the color is not uneven.

Further, in the second invention, in addition to these configurations, the second invention
In addition to the advantages of the first aspect of the present invention, since the applicator roll is provided with a paint reservoir for supplying the additional paint at a location upstream of the roll and downstream of the first roll, the applicator roll is changed from the first roll to the applicator roll. The amount of paint to be supplied can be made smaller than in the case of the first invention, and as a result, the rotation speed of the first roll can be made lower.
Compared with the invention, it is possible to further prevent foaming and scattering of the paint and contamination around the device.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

(Embodiment 1) In FIG. 1, which is a schematic view of one embodiment of the present invention, 11
Is a backup roll having an elastic material A such as a rubber material on the outer peripheral portion of a steel roll core, 13 has an outer peripheral portion made of a non-elastic material such as cemented carbide, and backs up the metal plate 12 in progress An applicator roll that applies paint to the metal plate 12 sandwiched between the roll 11 and 14 has an elastic material A such as a rubber material on the outer peripheral portion of a steel core roll. The first roll 18 for drawing in and applying the paint to the applicator roll 13 has an outer peripheral portion made of a non-elastic material such as cemented carbide.
Of the backup roll 11 which is downstream (or forward) of the first roll 14 in the rotation direction (direction of arrow d) of FIG.
It is a second roll that is located upstream (or rearward) of the roll and limits the paint thickness on the applicator roll 13.

Further, 15 is stored in the tray 16 and is the first roll.
A part of 14 is dipped in paint, 19 is a paint supply nozzle for supplying paint 15 to the pan 16, 20 is a wiper roll that is in contact with the backup roll 11, 21 is a scraper of the wiper roll 20, and 22 is a pan. is there.

In the present embodiment, the applicator roll 13 was provided with a cemented carbide having a surface roughness of 0.03 to 0.06 μm on the outer peripheral portion, but in addition to this, ceramics, hard metal plating, hard alloy coating or thermal spraying was used. You can also use the ones.

Further, as the elastic material A, rubber having a hardness of 40 ° to 90 ° or an elastic material or cloth substantially equivalent thereto can be used, but in the present embodiment, rubber having a hardness of 50 ° to 60 ° was used.

In the coating apparatus of this embodiment, the first roll 14 is rotated clockwise as indicated by the arrow e, and the applicator roll 13 is rotated.
Is rotated counterclockwise as indicated by arrow d, the second roll is rotated clockwise as indicated by arrow f, and the backup roll 11 is rotated counterclockwise as indicated by arrow g.
Was moved in the same direction as the backup roll 11 as indicated by arrow h. The coating material 15 in the tray 16 adheres to the elastic material A of the first roll 14, is pumped up, and is drawn into the pressure contact point 17 between the first roll 14 and the applicator roll 13, so that the applicator roll 13 with extremely high smoothness is formed. When it is pressed against the outer peripheral surface and adheres, and when it comes out of the press contact point 17, the first
It is divided into two parts, the residual amount on the roll 14 and the applied amount on the applicator roll 13. A part of the coating material 15a applied to the applicator roll 13 is part of the applicator roll 13 and the second
When the minute gap 23 formed by the roll 18 is filled and passed, the paint 1b having a desired thickness remains on the applicator roll 13, and the paint 15c having substantially the same thickness adheres to the second roll 18 and advances. The paint 15b remaining on the applicator roll 13 is
When it comes into contact with the metal plate 12, almost all moves to the metal plate 12,
The coating film 15d covers the surface of the metal plate 12.

Using the coating apparatus of the present embodiment, 100 times the viscosity of Ford cup # 4,25 ℃ epoxy paint for the inner surface of the can lid
When a strip aluminum plate was coated to a thickness of 70 mg / Dm ² (coating thickness after drying) at a speed of m / min and 200 m / min, uneven coating was observed at any speed. A coating having a uniform and desired thickness was obtained.

Furthermore, a vinyl chloride organosol paint for the inner surface of the can lid having a viscosity of 90 seconds has a thickness of 140 mg / Dm ² at a speed of 100 m / min and 200 m / min, on the epoxy coating film of the above-mentioned aluminum strip. It was applied to (coating thickness after drying), but no scratches were formed on the coated metal plate at any speed, and a coating having a uniform thickness without uneven coating was obtained.

The outer peripheral portion of the first roll 14 of this embodiment is made of the elastic material A.
As compared with the conventional non-elastic material pickup roll 4 shown in FIG. 4, the wettability with the paint is good and a sufficient amount of the paint 15 can be pumped up even at low speed rotation. Therefore, it is possible to prevent bubbles from being generated in the paint or the paint from being scattered.

Furthermore, by using a high-viscosity paint, the amount of solvent used is reduced, the amount of heat for drying is small, and the pollution control can be kept as it is.

(Embodiment 2) FIG. 2 is a schematic view showing another embodiment of the present invention.

The difference between this embodiment and the embodiment shown in FIG. 1 is that the metal plate 12 is sandwiched between the clockwise-rotating backup roll 31 made of an elastic material and the non-elastic material applied to the metal plate 12 in progress. That the rotation direction of the applicator roll 33 made of steel is clockwise, and that the coating material 35 is supplied and stored in the valley 39 formed by the applicator roll 33 and the first roll 34 made of elastic material, and the first roll. The rotation direction of 34 is counterclockwise, and the rotation direction of the second roll 38 made of an inelastic material is counterclockwise.

In the coating apparatus of this embodiment, the paint 35 stored in the valley 39 passes through the pressure contact point 37 between the first roll 34 and the applicator roll 33 and is pressed against the outer peripheral surface of the applicator roll 33 having extremely high smoothness. 37
As it exits, it is split into two parts, a residual part on the first roll 34 and a deposit part on the applicator roll 33.

When a part of the coating material 15a ′ applied to the applicator roll 33 passes through the minute gap 43 formed by the applicator roll 33 and the second roll 38, the coating material 15b ′ having a desired thickness remains on the applicator roll 33. , The paint 15c 'having substantially the same thickness adheres to the second roll 38 and advances.

When the coating material 15b 'remaining on the applicator roll 33 comes in contact with the metal plate 12, half of the coating material 15b' moves to the metal plate 12 and becomes a coating film 15d 'which covers the metal plate.

Also in the coating film experiment by the coating device of the present example, similar to the coating device of FIG. 1, a high-viscosity paint can be applied thinly at high speed without scratching the metal plate, and the formed coating film is uneven. It was of uniform thickness.

(Embodiment 3) FIG. 3 is a schematic view of another embodiment of the present invention.

The coating apparatus of this embodiment is the same as the coating apparatus shown in FIG. 1 except that a paint reservoir 25 formed by an applicator roll 13, a second roll 18 and a weir 24 is added to the paint reservoir 25. The additional coating material 26 is supplied to enable storage (the coating material supply nozzle 16 for supplying the coating material to the tray 16 is not shown).

In this device, the first roll 14 is the applicator roll.
Since the additional paint 26 of the paint reservoir 25 is added to the paint 15a that is pressed against the 13 and adheres to the applicator roll 13, the paint 15a that is adhered to the applicator roll 13 by the first roll 14 has the same film thickness as in FIG. Less than that of the device (i.e., the surface of the applicator roll 13 is only slightly wet with paint), and therefore the first roll 14 is rotated at a low speed (1/10 to 1 of the peripheral speed of the applicator roll 13). / 15, for example, 5 to 30 m / min), so that the foaming and scattering of the paint 15 are reduced.

As a result, there is little contamination of the working environment, and there is no uneven coating or foaming, and a thin and uniform coating film can be obtained.

In the coating apparatus of this embodiment, the backup roll 11
Is a steel roll having a rubber layer having a hardness of 30 to 90 on the outer peripheral portion, a steel roll is the second roll 18, and a rubber layer having a hardness of 50 ° to 60 ° on the outer peripheral portion is the first roll 14. Using the steel rolls each having, the applicator roll 13 has a hard chromium plating layer having a surface roughness of 0.04 to 0.05 μm and a surface roughness on the outer peripheral portion of the steel roll as the applicator roll 13.
Ceramic layer of 0.14 to 0.21 μm, surface roughness of 0.03 to 0.
For coating the top of the can lid with the same viscosity as the epoxy paint for the inner surface of the can lid, which has a viscosity of 90 seconds and 100 seconds at Ford cup # 4,25 ° C. Epoxy-based paint with a thickness of 70 mg / Dm ² (coating thickness after drying), vinyl chloride organosol paint with a coating speed of 150 m / min and 170 m / min, and vinyl chloride organosol paint with 140 m
Coating was applied to a strip-shaped aluminum plate to a thickness of g / Dm ² (coating thickness after drying).

The peripheral speed of the second roll 18 was adjusted to 1/10 of the peripheral speed of the applicator roll 13, and the peripheral speed of the first roll 14 was adjusted to 1/2 to 1/5 of the peripheral speed of the applicator roll 13.

For comparison, the epoxy-based paint and the vinyl chloride organosol paint were applied to the strip-shaped aluminum plate under the same conditions as above except that the first roll 14 was removed.

In the case of the apparatus of this example, a smooth and good coating film was obtained in each case. On the other hand, a comparative device (first roll 14
In the case of (1), the uniform coating film was not obtained at all.

(Effect of the Invention) According to the device of the present invention (first invention and second invention), a highly viscous paint can be applied uniformly and thinly to a metal plate at high speed. The use of the high-viscosity coating material gives a coating film having few bubbles, and further, the amount of solvent used and the amount of heat required for dry baking are small, and there is an effect that a metal plate is not scratched.

In addition to the above effects, the device of the present invention (the second invention) can further reduce the rotation speed of the first roll, so that the foaming of the coating material by the first roll is further reduced, and as a result, almost no bubbles are generated. The effect is that a dry coating film is obtained.

[Brief description of drawings]

 FIG. 1 is a schematic view of one embodiment of the present invention, FIG. 2 is a schematic view of another embodiment of the present invention, FIG. 3 is a schematic view of yet another embodiment of the present invention, and FIG. It is a schematic diagram of an example. 1,11,31 …… Backup roll, 2,12 …… Metal plate, 3,13,33 …… Applicator roll, 4 …… Pickup roll, 14,34 …… First roll, 18,38 …… Second Roll, 5,15,35 …… Paint 25 …… Paint reservoir 26 …… Additional paint A …… Elastic material.

Claims (2)

[Claims] 1. A backup roll made of an elastic material, an applicator roll made of a non-elastic material for sandwiching a thin metal plate between the backup roll and applying a high-viscosity paint to the thin metal plate in progress, and an outer periphery. Part of the portion is immersed in the coating material, the first roll made of an elastic material that draws the coating material between the applicator roll and applies the coating material to the applicator roll, and the first roll in the rotating direction of the applicator roll. A second roll made of an inelastic material, which is located at a position downstream of the first roll and downstream of the backup roll, and which limits the thickness of the coating material on the applicator roll between the second roll and the backup roll; A roll coating device capable of high-speed thin coating, characterized by being equipped. 2. A backup roll made of an elastic material, an applicator roll made of a non-elastic material for sandwiching a thin metal plate between the backup roll and applying a high-viscosity paint to the thin metal plate in progress, Part of the portion is immersed in the coating material, the first roll made of an elastic material that draws the coating material between the applicator roll and applies the coating material to the applicator roll, and the first roll in the rotating direction of the applicator roll. A second roll, which is located downstream of the first roll and downstream of the backup roll, and which limits the thickness of the paint on the applicator roll between the second roll and the applicator roll; A paint reservoir for supplying additional paint to the applicator roll at a location upstream of the second roll and downstream of the first roll. Characterized the door, high speed thin coating can roll coating device.