JP3102532B2 - Painting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

This invention relates to iron, stainless steel,
Metal plates such as aluminum or various films and tapes
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating apparatus for continuously coating a coating material such as a paint, ink, a magnetic material, an adhesive, a functional agent, etc. on a belt-like body such as a paper or a paper.

[0002]

2. Description of the Related Art Conventionally, various methods have been proposed as means for continuously applying a coating liquid to a traveling belt-like body. Typical examples thereof include a roll coating method and a curtain floor method. There are a coating method, an extrusion (extrusion die nozzle) coating method, a spray coating method and the like, which are applied in various industrial fields.

[0003] Among them, the extrusion coating method is shown in FIG.
Alternatively, as shown in FIG. 4, a die header (nozzle) 2 having a slit 1 through which a coating liquid is discharged (outflow) is opposed to a workpiece 3 in close proximity to a backup roll 4 or a support roll. A coating method in which the coating solution extruded from the slit 1 is coated on the workpiece 3 which is running while being supported by the roll 5, and is coated with a "roll roll" like a roll coating method. (Defects in the coating film surface caused by contact with the coating roll) "and the like do not occur, so that a coating film with a beautiful surface can be obtained.

[0004] In this extrusion coating method, FIG.
As shown in FIG. 6, after the coating solution is extruded from the die header-2 onto the surface of the workpiece 3, the blade is blazed at the die tip (die lip portion 6) to make the coating solution uniform. As shown in the drawings, there is a type in which the liquid film discharged from the die header-2 is applied to the workpiece 3 to form a coating film as it is.

On the other hand, similarly, the curtain coating method is a coating means which is expected to produce a coating film having a beautiful surface without concern about occurrence of "roll eyes". In this curtain coating method, as shown in FIG.
The coating material 3 is run under the coating liquid film flowing down from the slit 1 (in FIG. 7, the belt is driven by the conveyor belt 8), and a coating film is formed so as to cover the coating liquid film on the upper surface of the coating material 3. It is a way to make it. Here, reference numeral 9 in the drawing denotes a coating liquid capturing tank for collecting the coating liquid that has flowed down.

In the case of the curtain coating method, the distance from the slit 1 to the upper surface of the workpiece 3 is generally about 50 to 450 mm, and the coating film flowing out is contracted due to surface tension. Therefore, an edge guide such as a wire, a rod, or a chain is hung from both ends of the slit, and the both ends of the coating liquid film are made to follow the edge guide to prevent the contraction. This curtain flow coater is mainly used in a steel plate cutting plate line.

By the way, the above-mentioned coating method (extrusion coating method, etc.) in which a coating liquid is caused to flow out from a slit of a nozzle which extends in the width direction of the object and is opened and is applied to the surface of the object to be coated. It is needless to say that in the case of the curtain-flow coating method, in order to uniformly apply the coating liquid to the object to be coated, the discharge amount from the slit nozzle needs to be uniform in the width direction.

However, the width of the object to be coated is generally several hundreds to several thousands mm, and the width of the slit nozzle for applying the coating liquid to the object is equal to or larger than that. It was very difficult to discharge (flow out) the coating liquid uniformly from the substrate.

In order to uniformly discharge the coating liquid from the slit, a nozzle (die header) generally called "T type" shown in FIG. 8 or a "coat hanger" shown in FIG. Nozzles called "types" are used. This is intended to distribute the coating liquid supplied from one location of the nozzle uniformly in the width direction through a T-type or coat hanger-type flow path formed inside the nozzle.

However, when a single coating liquid is discharged under a certain condition, it is possible to discharge uniformly by designing the T-type or coat hanger type flow path in accordance with it. When the liquid and the application conditions are changed, the ejection becomes non-uniform, so that it is necessary to prepare a plurality of dies corresponding to the type of the application liquid and the application conditions.

However, as measures for solving such inconveniences, Japanese Patent Application Laid-Open No. 61-291117, Japanese Utility Model Application Laid-Open No. 2-25073, and Japanese Patent Publication No. 2-56272 have been proposed.
Nozzles that can adjust the slit gap in the width direction, as seen in Japanese Patent Application Laid-Open No. H10-264, have been proposed.

However, in the above-described coating apparatus for adjusting the slit gap of the nozzle, although the discharge flow distribution in the nozzle width direction can be made uniform by finely adjusting the slit gap in the nozzle width direction, the discharge speed of the coating liquid film is reduced. There was a problem that it was difficult to make it constant. In other words, even when the slit gap is made uniform in the nozzle width direction, the “coating liquid temporarily stays in the nozzle (liquid reservoir: generally used for any nozzle in order to make the discharged liquid film uniform). This is because if the pressure of the coating liquid is uneven in the width direction of the nozzle, the discharge flow rate (discharge flow rate) also becomes uneven in the width direction.

In this case, since the discharge amount is large where the above-mentioned coating liquid pressure is partially high, in the proposed nozzle device, the resistance is increased and the discharge amount is reduced by narrowing the nozzle slit gap in this portion. Is taken.

However, if the discharge amount is made the same by partially narrowing the nozzle slit gap, the discharge liquid film speed of the coating liquid is increased as compared with the case where the nozzle slit gap is wide. This results in non-uniformity of the speed in the slit width direction. As described above, even if the discharge flow rate is constant in the nozzle width direction, if there is a non-uniformity in the discharge speed, the non-uniformity will also occur in the portion applied to the workpiece.

For example, consider the case where the liquid film speed at a place where the nozzle slit gap is wide is lower than the moving speed of the object to be coated, and the liquid film speed at the place where the nozzle slit gap is narrow is faster than the moving speed of the object to be coated. In the former, the liquid film is stretched and applied to the object to be coated, whereas in the latter, the liquid film is applied while stagnating on the surface of the object to be coated. As a result, even when the film thickness when applied to the object to be coated is uniform, the flow state of the application liquid in the portion where the liquid film is applied to the object to be coated is different as described above. Unevenness (wrinkle-like unevenness) occurs in the portion, and the quality of the product is degraded.

In the above example, the speed difference between the liquid film and the object to be coated is extremely large. In any case, if there is a difference between the liquid film speeds in the slit width direction, the traveling speed of the object to be coated is reduced. Despite being constant in the width direction, there is a difference in the flow of the liquid film at the portion where the liquid film is applied to the object to be coated, and the occurrence of turbulence causes uneven application. Therefore, it is necessary to make the thickness and speed of the liquid film discharged from the nozzle uniform in the slit width direction in order to perform a beautiful surface coating. There was a limit to beautification.

In view of the above, an object of the present invention is to provide a coating apparatus capable of forming a coating film having a uniform and beautiful surface at high speed in the width and length directions of a band-shaped object to be coated. is there.

[0018]

Means for Solving the Problems The present inventor has conducted intensive studies to achieve the above object, and as a result, has stated that "a uniform and beautiful coating film is applied to a strip-shaped workpiece to be moved by a coating apparatus using a slit nozzle. In order to form the coating liquid, it is necessary to provide an adjusting means for equalizing the coating liquid pressure in the nozzle width direction in a portion where the coating liquid inside the nozzle temporarily stays (liquid storage portion) to rectify the flow of the coating liquid. No research was conducted after reaching the conclusion of "No", and it was easy to adopt the "method of adjusting the width of the coating liquid flow path" for adjusting the coating liquid pressure inside the nozzle and rectifying the flow of the coating liquid. In addition, the change / adjustment of the flow channel width can be performed very easily and appropriately by utilizing the deformation of the rubber-like elastic body. "

The present invention has been completed based on the above findings and the like. "The nozzle (die / header) is arranged to face a continuously running belt-shaped article to be coated, and the width of the article to be coated is determined. A coating device for applying a coating liquid having an arbitrary thickness to a surface of a workpiece to be coated, the coating liquid flowing out of a slit of the nozzle extending and opening in the direction. together arranged sideway control rods made of a rubber-like elastic body portion ") in the longitudinal direction, or placing the adjusting rod to the control rod partially compressed and deformed, or further from the rubber-like elastic body By adopting a configuration in which a control rod made of hollow is filled with a pressurized fluid and a device for controlling the pressure of the pressurized fluid is additionally provided, the amount of the coating solution flowing out of the slit is made uniform in the width direction. Become uniform and beautiful In that a unique coating film is formed. "

That is, the present invention is applied to extrusion coating or curtain coating, etc., and is a nozzle (die header) for pressurizing or spontaneously flowing a coating solution through a slit having a predetermined gap. The present invention is described in more detail below with reference to the drawings.

FIG. 1 is a schematic explanatory view showing a main part of a coating apparatus according to a first embodiment of the present invention. In FIG.
11 is a nozzle for applying the coating liquid (die header)
The coating is applied to the surface of the belt-like body by disposing the coating liquid through a slit 12 provided in the width direction of the belt-like body, which is arranged to face a continuously running belt-like body (object to be coated). This is a device for applying a liquid at an arbitrary thickness.

However, unlike the conventional one, in the nozzle 11 according to the present invention, the control rod made of at least one rubber-like elastic body (rubber or the like) is provided in the liquid reservoir 13 inside the nozzle.
14 are located. Note that the control rod 14 is
And is laid down in the nozzle width direction (longitudinal direction) while being sandwiched between them.

The push pad 15 is rotatably connected to an adjusting rod 16, and the adjusting rod 16 is rotatably connected to an adjusting screw 18 via an O-ring 17 incorporated in the nozzle body. Here, it goes without saying that the O-ring 17 is provided to prevent the leakage of the coating liquid. The push pad 15, the adjusting rod 16, and the adjusting screw 18 are divided into a plurality in the width direction of the nozzle and are arranged. A plurality of control rods 14 made of rubber-like elastic material are partially adjusted from the outside of the nozzle by the adjusting screw 18. It can be compressed and deformed.

FIG. 2 is a schematic explanatory view showing a main part of a coating apparatus according to a second embodiment of the present invention. In this device,
The control rod 14 'made of rubber-like elastic material is hollow, and is filled with a pressurized fluid, so that the pressure of the pressurized fluid can be adjusted by a control device (not shown) outside the nozzle. I have. The other mechanism structure is shown in FIG.
It is the same as that shown in.

[0025]

In the device of the present invention shown in FIGS. 1 and 2,
A control rod 14 (14 ') made of a rubber-like elastic material is disposed in a liquid reservoir 13 inside the nozzle 11 in which the coating liquid discharge slit 12 is opened, and the control rod is partially removed from outside the nozzle. Since an adjusting rod 16 and the like for compressive deformation are provided, the slit 12 is used for coating the traveling belt-shaped workpiece.
In the case where the flow rate of the application liquid from the nozzle becomes uneven in the width direction, the adjusting screw 18 is turned to move the plurality of adjusting rods 16 independently of each other, and the control rod 14 (14 ') is partially compressed. The gap between the upper nozzle and the upper nozzle is partially changed. As a result, the “slit direction (slip
The flow resistance of the coating liquid flow in the direction in which the coating liquid is to be discharged
Pressure upstream of 12 (passing through the gap between control rod and upper nozzle
(The fluid pressure at the site where the pressure has been changed) can be made uniform in the nozzle width direction.

As described above, if the pressure upstream of the slit from which the coating liquid is discharged inside the nozzle is made uniform in the width direction of the nozzle, if the nozzle slit gap is uniform in the width direction, the speed and the speed of the liquid film to be discharged can be improved. The flow rate becomes uniform in the nozzle width direction, and beautiful and uniform coating can be performed without the above-mentioned coating unevenness.

In this case, it is assumed that the slit gap of the nozzle is constant in the width direction. However, if a conventionally known slit gap adjusting type nozzle is used as a base, "nozzle production accuracy" It is also possible to cope with the case where the slit gap in the width direction becomes non-uniform due to "defective" or "nozzle deformation due to use under high nozzle pressure". However, in this case, it is needless to say that the nozzle slit gap adjustment is to keep the slit gap constant in the width direction, and the discharge flow rate of the coating liquid is performed by compressive deformation of the rubber-like elastic control rod inside the nozzle. .

Further, as shown in the apparatus shown in FIG. 2, the control rod 14 'made of a rubber-like elastic material is made "hollow", and the hollow portion is filled with a pressurized fluid. If the pressure can be adjusted from the outside of the nozzle, coating unevenness can be more easily suppressed and the coating film thickness can be controlled.

That is, if the deformation of the control rod 14 'is adjusted by the adjusting screw 18 so that the coating unevenness in the width direction does not occur at a certain coating film thickness, the pressurized fluid in the hollow control rod 14' can be adjusted. By simply changing the pressure, the "gap between the upper nozzle and the control rod" changes almost in proportion to the gap before adjustment in the nozzle width direction, so that the discharge flow rate can be uniformly adjusted and the film thickness can be changed. .

However, depending on the thickness of the applied film and the accuracy of the applied film, a large change in the applied film thickness cannot be sufficiently coped with only by adjusting the pressure of the pressurized fluid in the hollow control rod. Alternatively, it is necessary to change the supply amount of the coating liquid.

By the way, in the example shown in FIG. 1 or FIG. 2, the compression deformation of the control rod 14 (14 ') made of a rubber-like elastic body is performed by manually operating the adjusting screw 18 via the O-ring 17. However, if a technique such as rotation control using a small motor or the like, fluid pressure control using a hydraulic or pneumatic cylinder, or temperature control using expansion and contraction of a solid is applied, uniform beautiful painting can be automated.

Next, the effects of the present invention will be described with reference to examples.

EXAMPLES Table 1 shows the results of comparison of the results of a coating test using the apparatus of the present invention with those of the conventional apparatus.

[0033]

[Table 1]

In the application test, the tip of the upper nozzle is partially pressed toward the gap side with bolts which are arranged in the slit direction in the slit of the nozzle shown in FIG. "Slit gap adjusting type nozzle for adjusting the slit gap (Japanese Patent Laid-Open No. 61-291117)
The nozzles used in the present invention were manufactured with a width of 500 mm. The slit gaps of the nozzles used in the examples of the present invention were finished with an accuracy of 0.23 ± 0.005 mm.

In the coating test, the coating method shown in FIG. 3 was adopted, and two types of coatings shown in Table 1 were applied to a 450 mm wide, 0.27 mm thick, galvanized steel sheet with the line speed changed. . In this test, a bright steel plate to which no primer was previously applied was used in order to accurately measure the distribution of the coating film thickness in the width direction.

Here, the thickness of the coating film was determined for the paint A (Table 1).
), The number of rotations of the paint supply pump (gear pump) to the nozzle is controlled in accordance with the line speed so that the dry film thickness becomes 20 μm and the paint film B becomes 24 μm in dry film thickness. In order to be uniform, in the present invention example
The compressive deformation and the pressurized fluid pressure of the elastic body during the air control rods made of rubber, also to adjust the nozzle slit gap in the conventional example.

The coated steel sheet was dried by heating at 230 ° C. for 60 seconds in an electric heating furnace and then allowed to cool. After cooling, the coating thickness in the steel sheet width direction was measured at a pitch of 10 mm.

As shown in Table 1, the thickness distribution in the width direction of the conventional example varied from 6 to 13% (accuracy / average thickness), whereas the variation of the present invention was 2%.
It can be seen that the uniformity is greatly improved, that is, to 5%.

Further, the surface finish condition was not good at high speed in the conventional example, whereas it was very good in the present invention example. The surface finish was visually determined, but the condition was determined by copying a fluorescent lamp, a window frame, or the like onto the painted surface and determining its linearity. That is, if there is unevenness (uneven film thickness) on the painted surface, the image appears to be deformed, so this determination method is considered to be appropriate. Since this test was conducted in a general test room where clean room was not performed, dust called "bubbles" adhered to the coated surface after baking and drying, but this was excluded from the judgment. .

[0040]

As described above, according to the present invention, it is possible to realize a coating apparatus capable of stably performing a continuous high-speed beautiful coating on a belt-like object, and to improve productivity and quality of a coated steel sheet, for example. Industrially extremely useful effects such as a large contribution can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an essential part showing an example of a coating apparatus according to the present invention.

FIG. 2 is a schematic explanatory view of a main part of a coating apparatus according to another example of the present invention.

FIG. 3 is an explanatory view of a conventional extrusion coating method (die coating method).

FIG. 4 is an explanatory diagram relating to another embodiment of a conventional extrusion coating method (die coating method).

FIG. 5 is a detailed explanatory view of a coating section in extrusion coating (die coating).

FIG. 6 is a detailed explanatory view of a coating section in another form of extrusion coating (die coating).

FIG. 7 is an explanatory view of a conventional curtain coating method.

FIG. 8 is an explanatory diagram of a conventional T-type nozzle (die header).

FIG. 9 is an explanatory view of a conventional coat hanger type nozzle (die header).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Slit 2 Die header (nozzle) 3 Coating object 4 Backup roll 5 Support roll 6 Die lip part 7 Nozzle 8 Conveyor belt 9 Coating liquid capture tank 11 Nozzle (die header) 12 Slit 13 Liquid reservoir 14 Control rod 14 'Control rod 15 Push pad 16 Adjustment rod 17 O-ring 18 Adjustment screw

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Masahiro Sugihara 4-2-2 Kannon Shinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Mitsubishi Heavy Industries, Ltd. Hiroshima Laboratory (56) References JP-A-62-95174 (JP, A) JP-B-56-49628 (JP, B2) JP 2-31163 (JP, Y2) JP-B 1-16524 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B05C 5/02 B05D 1/26 G11B 5/848 B05B 1/04

Claims (2)

(57) [Claims] 1. A nozzle is disposed opposite to a continuously running belt-shaped article to be coated, and a coating liquid flowing out of a slit of the nozzle, which extends in the width direction of the article and is opened, is arbitrarily applied to the surface of the article to be coated. In a coating apparatus for applying a coating with a thickness, a control rod made of a rubber-like elastic body is placed in the liquid reservoir inside the nozzle in the longitudinal direction thereof, and an adjusting rod for partially compressively deforming the control rod is installed. A coating apparatus characterized by the above-mentioned. 2. The control rod according to claim 1, wherein the control rod made of a rubber-like elastic body is hollow and filled with a pressurized fluid therein, and a device for controlling the pressure of the pressurized fluid is additionally provided. Coating equipment as described.