JPH0543426B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a coating device using a roll for applying a coating material such as a paint or an adhesive to the surface of a plate-like object, a sheet-like object, or the like.

BACKGROUND ART Conventionally, various coating devices using rolls are known.

FIG. 4 shows a schematic side view of a natural roll coater that rotates a coating roll in the same direction as the conveying direction of the object to be coated. A natural roll coater consists of a naturally rotating application roll for applying a coating material to a surface to be coated, a doctor roll that supplies the coating material to the application roll while adjusting the supply amount, and a The coating material is applied to the object to be coated, which is conveyed in the direction of the arrow between the conveyor having an under roll and the application roll. Various coating operations can be performed by adjusting the relative relationship between the rotational speed of the applicator roll and the conveyance speed of the object to be coated, the distance between the applicator roll and under roll, the amount of coating material on the applicator roll surface, etc. obtain.

FIG. 5 shows a schematic side view of a reverse roll coater that rotates a coating roll in a direction opposite to the conveyance direction of the object to be coated. The reverse roll coater has the same configuration as the natural roll coater,
The difference is that the application roll rotates in reverse. Reverse roll coaters can also be used by adjusting the relative relationship between the rotational speed of the application roll and the conveyance speed of the material to be coated, the distance between the application roll and the under roll, and the amount of coating material on the surface of the application roll.
Various application operations can be performed.

Problems to be Solved by the Invention In the above-mentioned natural roll coater and reverse roll coater, the coating material is supplied to the valley between the applicator roll and the doctor roll, and the gap between the applicator roll and the doctor roll is adjusted. The coating amount is adjusted by the trough, and baffles are provided at both axial ends of the applicator roll and doctor roll in this valley, and the coating material is stored in the recesses formed by them. Ru. However, the amount of coating material stored in this valley is small, and it is not possible to completely prevent coating material from flowing out between the rolls and the baffle plate, resulting in a large amount of coating material loss and soiling the equipment. It has the disadvantage that it is easy to clean and therefore requires frequent cleaning. In addition, because the storage volume is small, dirt and paint scum can easily get mixed in, and if the blade wears out, errors in the amount of coating may occur, requiring frequent maintenance and inspection. .

Although it depends on the relative relationship between the conveyance speed of the object to be coated and the rotational peripheral speed of the coating roll, in the general usage of a natural roll coater, the coating material is rubbed into the surface to be coated, so the surface becomes porous. When coating a porous substrate, the coating material gets into the recesses on the surface, resulting in a bridging phenomenon (when coating a porous substrate, the paint cannot penetrate into the holes, causing the holes to disappear). With air taken inside,
This refers to a phenomenon in which a bridge-like coating film is formed only on the surface of the hole. When heated later to dry the paint, the air inside the holes expands and the paint film on the surface may rupture) and has the advantage of improving the adhesion of the paint to the surface being coated. Roping (a phenomenon in which when coating a base material with a roll, the paint is pulled by the roll due to the viscosity of the paint at the part where the roll moves away from the base material. There will be wrinkles in the shape of mountains on the exposed areas)
This easily occurs, and it is not possible to increase the amount of coating.

In addition, with a reverse roll coater, since the coating material is applied while being placed on the surface to be coated, roving is less likely to occur and the amount of coating can be increased, but since the coating material is not rubbed in, it is possible to When applied to a coated object, there is a drawback that a bridging phenomenon tends to occur.

In order to compensate for these drawbacks, a method is also used in which a coating material is once applied using a reverse roll coater and the coating material is scraped off while rubbing the coating material on the coated surface with a reverse roll. In this case, at least two coating devices are required.

A roll coater that can be used for both natural rotation and reverse rotation has been proposed, in which a doctor roll and a blade are combined on one coating roll that can be rotated in forward and reverse directions for both natural rotation and reverse rotation. However, the structure is complicated, switching between natural rotation operation and reverse rotation operation is troublesome, maintenance is complicated, and work efficiency is poor.

Means for Solving the Problems It is an object of the present invention to provide a coating device with a novel configuration that can overcome the disadvantages of the prior art described above. That is, the coating device according to the present invention comprises: a coating material box having a coating material supply port; a coating material supplying means for supplying a coating material into the coating material box beyond the level of the coating material supply port; A coating roller whose circumferential surface partially enters the coating material supply port of the coating material box and is provided at a position in contact with the surface to be coated to which the coating material is to be applied; and a pressure reducing means for preventing the coating material from overflowing from the gap by sucking outside air from the gap between the coating material supply port and the coating roll, and the coating material is applied from the coating material supply port. It is characterized in that the coating material transferred to the peripheral surface of the roll is applied to the surface to be coated as the coating roll rotates.

The amount of coating can be adjusted by adjusting the gap between the coating material supply port and the roll.

Effects According to the present invention, even if the coating material is supplied to the coating material box beyond the level of the coating material supply port, the coating material is removed by suction of air from the gap between the supply port and the coating roll. will not overflow from the gap.

In addition, the excess coating material is removed from the roll surface by the high-speed air flow sucked through the gap, and the speed of the air flow is equal to the area of the gap, assuming that the negative pressure inside the coating material box is constant. It changes depending on. Therefore, it is possible to adjust the appropriate coating amount by adjusting the gap. At this time, the sucked air rises through the coating material and agitates the coating material, so that settling of solids in the coating material and separation of coating material components can be prevented.

Adjustment of the coating amount depends on the viscosity of the coating material, the negative pressure inside the coating material box, the gap between the coating material box and the roll, the relative relationship between the rotational peripheral speed of the coating roll and the conveyance speed of the object to be coated, and the coating material. This can be done by adjusting the amount of coating material on the roll surface (in extreme cases, only the solvent is applied to the roll surface), but basically by adjusting the gap between the supply port and the roll. Fine adjustments can be made by adjusting the negative pressure in the coating material box.

Further, by adjusting the gap and the negative pressure, the coating material can be completely removed from the roll surface, thereby allowing the roll to function as a scraping roll for the coating material.

By enabling the application roll to rotate forward and backward,
It can be used commonly as a natural roll coater and a reverse roll coater, and does not require any additional means for this purpose, thus simplifying the configuration of the device and reducing the cost of the device.

Since the structure of the device is simplified, maintenance and inspection become easier.

EXAMPLES The outline of the present invention has been described above, and the present invention will be described in further detail below with reference to the drawings.

FIG. 1a is a schematic side view of the coating device according to the present invention, b is a schematic front view of the coating material box and roll portion of the device of FIG. 1a, and c and d are of the coating device of FIG. 1b. It is a similar schematic front view of a modified example, and 10 is a coating material box, 20 is a roll means, 30 is a coating material supply means, and 4
0 represents a pressure reduction means, 50 represents a coating material extraction means, 60 represents a secondary air intake means, and 70 represents a gas-liquid separation means.

The coating material box 10 is open at the top, has a rectangular coating material supply port 11 at the lower part, and has a structure in which the opening at the top can be hermetically sealed with a lid 12. It is shown. The supply port 11 may be provided on the bottom wall of the coating material box, may be provided on the corner where the bottom wall and the side wall meet (Fig. 1c), or may be provided on the side wall (Fig. 1c). Figure 1 d). What is required is that the coating material can be stored up to a level above the supply opening 11.

The roll means 20 includes a cylindrical application roll 21
and an under roll 22. The coating roll 21 may be made of any material such as rubber, synthetic wood, metal, etc.
It is arranged close to the supply port 11, and a portion thereof enters into the supply port 11. Specifically, the gap between both ends of the application roll 21 in the axial direction and the edge of the supply port 11 adjacent thereto is minimized, and the gap between the roll surface of the application roll 21 and the supply port 11 adjacent thereto is minimized. so that there is a gap between the edges of
Part of the coating roll is stuck inside the coating box.
The under roll 22 rotates in the direction of the arrow and conveys the object to be coated in the direction of the arrow A. Application roll 2
1 is preferably capable of forward and reverse rotation as shown by the arrows. This allows one coating device to be used both as a natural roll coater and as a reverse roll coater.

The coating material supply means 30 is shown as having a coating material tank 31, a pipe 32 for supplying the coating material from the coating material tank 31 to the coating material box 10, and a pump 33 connected to the pipe. It is desirable to maintain a constant liquid level of the coating material in the coating material box. Various types of liquid level maintaining means are known and therefore will not be described in detail.

The pressure reducing means 40 includes a pipe 41 connected to the upper part of the coating material box 10 and a vacuum pump 4 connected to the pipe.
2. The depressurizing means 40 does not need to be directly connected to the coating material box; instead, by providing a ventilation means that communicates the upper parts of the coating material box and the coating material tank, and reducing the pressure inside the coating material tank, the coating material can be indirectly connected to the coating material box. The inside of the box may be depressurized.

The coating material is supplied into the coating material box 10 from the coating material supply means 30 beyond the level of the coating material supply port 11,
On the other hand, the pressure inside the coating material box is reduced by the pressure reducing means 40. Due to this reduced pressure, outside air is sucked at high speed from the gap between the supply port 11 and the application roll 21, so that the coating material does not overflow from the supply port 11. Even if there is a slight gap between both axial ends of the coating roll and the edge of the supply port 11 adjacent to them, the coating material will not leak due to air suction. This solves one of the drawbacks of the prior art.

The air sucked into the coating material box from the supply port 11 is
It rises in the coating material as air bubbles and escapes into the air above the coating material box. At this time, the coating material is vigorously stirred to prevent solid content contained in the coating material from settling and separation of coating material components. Furthermore, the stirring action is effective in preventing the generation of coating material scum. A large amount of coating material is stored in the coating box, and since the coating material box is covered with a lid, there is little dust contamination.

Although droplets of the coating material are carried out into the air along with the above-mentioned air bubbles, the droplets of the coating material may be collected by the gas-liquid separation means 70. Various types of gas-liquid separation means are known and therefore will not be described in detail. Furthermore, as shown in the illustrated embodiment, a plurality of baffle plates 71 are provided on the upper part of the coating material box, and the air flow is directed toward the liquid surface of the coating material to prevent gravity and/or centrifugal force. Alternatively, the droplets may be collected.

When the negative pressure inside the coating material box becomes higher than the expected value, there is a risk that the coating material may overflow from the gap.
Therefore, it is desirable to provide coating material removal means 50. The coating material extraction means 50 includes a pipe 51 connected to the bottom of the coating material box and a valve 52 provided on the pipe.
It is shown as. The valve 52 is normally closed, and is configured to automatically open when a pressure higher than a predetermined value is detected by a pressure detection means (not shown) provided in the coating material box. It can be done. Such detection means and automatic valves themselves are well known and will not be described in detail.

The secondary air intake means 60 is shown as consisting of a pipe 61 and a valve 62. valve 62
By opening and closing, you can adjust the negative pressure inside the coating material box and finely adjust the amount of coating material transferred to the coating roll.

The gap between the coating material supply port 11 and the roll surface of the applicator roll 21 defines the amount of coating material received onto the roll surface. In order to adjust the coating amount, it is desirable to be able to adjust the gap between the coating material supply port 11 and the coating roll 21. Such means may be of construction well known in mechanical technology. For example, as shown in FIG. 2a, the opening adjustment plate 13 may be movably provided at the edge of the coating material supply port 11 and fixed by appropriate fixing means 14, and as shown in FIG. 2b. Similarly, adjusting means may be provided to relatively move and fix the coating material box 10 and the rotating shaft of the coating roll 21 in two orthogonal directions as shown by the arrows. Such structures are well known in mechanical technology and therefore will not be described in detail.

In the above description, the coating material supply port 11 has a rectangular shape, and the roll surface of the coating roll 21 has a cylindrical shape. However, if the surface of the object to be coated is not flat, the roll surface of the coating roll can be deformed to correspond to the coating surface. Furthermore, the roll surface can be deformed in order to apply partial coating to a flat surface to be coated. Third
Figures a to d show plan views of the coating roll 21 having such a deformed roll surface and the aperture adjusting plate 13 used in combination therewith. By changing the shape or arrangement relationship between the deformed roll surface and the aperture adjustment plate, it is also possible to provide partially different coating amounts.

Figure 3a shows an applicator roll 21 with a cylindrical roll surface and an aperture adjusting plate 1 used in combination with the applicator roll 21.
3. This combination was explained in the example above.

FIG. 3b shows a coating roll 21 in which a plurality of lands are formed by a large diameter portion L and a small diameter portion S, and an aperture adjusting plate 13 used in combination therewith. Width of the convex portion of the aperture adjustment plate 13
w ₁ is smaller than the width w ₂ of the small diameter portion of the applicator roll 21, so that when they are used in combination, an equal gap is formed between them. Thus, the coating material is transferred to an even thickness on the uneven roll surface of the coating roll 21. When these combinations are applied to the surface of an object to be coated that has grooves with an uneven cross section similar to the uneven shape of the aperture adjustment plate, it becomes possible to apply coating with an even coating thickness to the uneven surface of the object to be coated. . It is unnecessary to explain that by changing the gap between the coating roll 21 and the aperture adjustment plate, coating with different thicknesses or even partial coating is possible.

FIG. 3c is a similar drawing showing a coating roll 21 having a corrugated roll surface and an aperture adjusting plate 13 used in combination therewith. It is unnecessary to explain that these can be used to coat the surface of a corrugated sheet. As described above, by changing the gap between the coating roll surface and the aperture adjustment plate, coating with different coating thicknesses or partial coating is also possible.

FIG. 3d is a similar drawing showing a coating roll 21 having a sawtooth cross-sectional shape and an aperture adjusting plate 13 used in combination therewith. Using these, various coatings of corrugated sheets with serrated cross sections are possible.

The above-mentioned application roll 21 and aperture adjustment plate 13 do not need to be used in the above-mentioned combination, and they can be used in other combinations depending on the purpose.
Further, application rolls and aperture adjusting plates of other shapes can also be used.

For example, the above-mentioned applicator roll and aperture adjustment plate are suitable for cases where the object to be coated has convex stripes parallel to the conveying direction, but by changing the shape of the applicator roll, it is possible to It will be readily understood that it is also possible to apply a coating material to the surface of. In this case, on the surface of the coating roll,
It is necessary to provide unevenness in the circumferential direction of the applicator roll that corresponds to the unevenness in the transport direction of the object to be coated.

Effect of the invention The effects of the present invention are as follows.

1 Using the same equipment, it is possible to apply coating materials in all the various application modes using a conventional natural roll coater and reverse roll coater, and it is easy to switch between these operations 1 There is no leakage of coating material from between the application roll and the baffle plate, and the equipment can be prevented from becoming dirty.1 The coating material in the coating material box is automatically stirred,
Prevents sedimentation of solids in coating material and separation of coating material components 1. Easy to adjust coating amount 1. Easy to maintain and inspect the equipment

[Brief explanation of drawings]

FIG. 1a is a schematic side view of a coating apparatus for carrying out the method of the present invention, FIG. 1b is a schematic front view of the coating material box and roll portion of the apparatus of FIG. Diagram c
and d are similar schematic front views of the modified example shown in FIG. 3a to 3d are plan views of a part of the coating roll and an aperture adjustment plate used in combination with each roll, FIG. 4 is a schematic side view of a natural roll coater according to the prior art, and FIG. 5 is a reverse roll coater according to the prior art. FIG. 2 is a schematic side view of a roll coater. Explanation of symbols, 10: Coating material box, 11: Coating material supply port, 12: Lid, 13: Opening adjustment plate, 14: Fixing means, 20: Roll means, 21: Application roll, 2
2: Under roll, 30: Coating material supply means, 3
1: Paint tank, 32: Piping, 33: Pump, 4
0: pressure reduction means, 41: piping, 42: vacuum pump,
50: Coating material removal means, 51: Piping, 52:
Valve, 60: Secondary air intake means, 61: Piping,
62: Valve, 70: Gas-liquid separation means, 71: Baffle plate.

Claims (1)

[Scope of Claims] 1 A coating material box having a coating material supply port, a coating material supplying means for supplying a coating material into the coating material box beyond the level of the coating material supply port, and a peripheral surface of the coating material supplying means for supplying a coating material into the coating material box beyond the level of the coating material supply port, and A coating roll that partially enters the coating material supply port of the coating material box and is provided at a position in contact with the surface to be coated to which the coating material is to be applied; and a pressure reducing means for preventing the coating material from overflowing from the gap by sucking outside air from the gap between the coating material supply port and the coating roll. A coating device characterized in that the transferred coating material is coated on the surface to be coated as the coating roll rotates. 2. The coating device according to claim 1, further comprising an opening adjustment means for adjusting a gap between the coating material supply port and the coating roll. 3. The coating device according to claim 1 or 2, wherein the coating roll is provided so as to be rotatable in forward and reverse directions.