JP2532902Y2 - Coating equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention is applied to a process for coating a steel sheet in an iron making machine, a paper coater of a paper making machine, etc.
The present invention relates to a coating apparatus that applies a liquid coating liquid to a material to be coated (hereinafter, referred to as a web) such as a steel plate or plastic.

[0002]

2. Description of the Related Art In a conventional coating process of a steel sheet surface, a method of holding a coating liquid on a coating roll, pressing the coating liquid on a running workpiece, and applying the coating liquid has been adopted in many cases. However, the present inventors proposed a non-contact coating method in Japanese Utility Model Application No. 1-220244 in order to improve coating quality. FIG. 7 is a cross-sectional view of a coating apparatus using a conventional non-contact coating method. An air nozzle 6 is mounted on the back of a coating liquid nozzle 5 and is supported by a backing roll 1 and travels with its rotation. The air layer 7 entrained by the web 2 is cut off by the airflow 8 that is blown from the tip 6 a of the air jet nozzle 6 in the direction opposite to the running direction of the web 2. Further, actually, the space 10 formed by the coating liquid film 3 ejected from the coating liquid ejection nozzle 5 ′ at the tip of the coating liquid nozzle 5 and the air flow 8 ejected from the air nozzle 6 becomes a decompression space. ′ Prevents air from remaining (mixing) into the web 2 and achieves stable coating on the web 2 (high quality coating with no coating defects on the coated surface). Further, with respect to the coating liquid film 3, the excess coating liquid is scraped off by the blade 4, the coating amount is adjusted, and the coating film is smoothed to form the coating layer 9. As described above, according to the conventional apparatus shown in FIG. 7, there is no mixing of impurities falling from the surrounding environment at the time of coating, and it is possible to prevent air bubbles from being mixed into the coating liquid film 3 even in the case of high-speed coating. A coating film can be formed.

FIG. 8 shows an example of a coating width defining device in a conventional coating device. As shown in FIG. 8, a coating liquid nozzle 5 is discharged onto a web 2 wound around a backing roll 1 and conveyed. In the apparatus for transferring the coating liquid film 3 to form a coating width on the web 2, when the width of the backing roll 1 of the web 2 in the axial direction is reduced, the coating layer to be formed on the web 2 is formed. In a case where the width of the backing roll in the axial direction is to be reduced, the coating liquid film 3 discharged from the coating liquid nozzle 5 is coated on the surface of the web 2 at the coating unnecessary area (both ends of the web in the backing roll axial direction), And the surface of the backing roll 1 (the area where the web is not wound)
It is necessary to take measures to prevent it from adhering to and contaminating it. In such a case, the coating liquid nozzle 5 is conventionally used so that the coating liquid film 3 discharged from the coating liquid nozzle 5 does not adhere to the coating unnecessary area.
The jet flow of the coating liquid film 3 discharged from the coating liquid nozzle 5 by inserting the side seal plate 20 into an area corresponding to a coating unnecessary area between the discharge port of the web 2 and the surface of the web 2 or the backing roll 1, Before reaching the surface of the web 2 or the backing roll 1, a mechanism that is blocked by the side seal plate 20 has been adopted.

FIG. 9 shows an example of another conventional coating apparatus, in which a coating liquid film discharged from a slit formed between coating liquid nozzles 5a and 5b on the surface of a moving web 2 is shown. In this apparatus, an entrained air boundary layer 21 is formed on the surface of the web 2 as the web 2 moves. That is, the entrained air boundary layer 21 is sandwiched between the flowing coating liquid film 3 and the surface of the web 2 at the position where the coating liquid film 3 comes into contact with the surface of the web 2, and Air bubbles 22 may be formed between the layer of the coating liquid film 3 and the coating liquid film 3. When the viscosity and the surface tension of the coating liquid film 3 are low, the air bubbles 22 pop off to generate coating defects 23, which may significantly lower the coating quality. In order to prevent such a coating failure due to the web entrained air boundary layer 21, in the conventional apparatus shown in FIG. 9, the coating liquid film 3 and the surface of the web 2 come into contact with each other in the vicinity of the upstream side in the web movement direction. The rigid plate 24 is provided close to the surface of the web 2.

[0005]

[Problems to be Solved by the Invention] In recent years, the demands for coating machines by customers have been steadily increasing, and the demands for coating quality such as cosmetic coating have become increasingly complicated and sophisticated. I have. Therefore, the physical properties of the coating liquid have been diversified, and a high degree of consideration has been required for coating film thickness accuracy, uniformity, and the like. In this case, if there is a contact part between the equipment and the web 2,
Inconveniences such as an increase in replacement frequency due to abrasion of members, an increase in maintenance costs, and instability of coating quality due to the use of worn parts occur. Therefore, adoption of the non-contact coating method has a large effect of solving the problem. In a non-contact coating method, as shown in FIG.
Is a method that uniformly ejects the air in the width direction of the web 2 and removes the wake air as described in Japanese Utility Model Application Laid-Open No. 1-220244. Good coating is required. Therefore, the realization of a highly responsive coating apparatus in view of the complexity of the coating conditions is an issue.

In the case of the conventional apparatus shown in FIG.
Since the jet of the coating liquid film 3 discharged from the coating liquid nozzle 5 strikes the side seal plate 20, the side seal plate 20 is contaminated with the coating liquid. Therefore, maintenance such as cleaning of the side seal plate 20 is required. When the gap between the discharge port of the coating liquid nozzle 5 and the web 2 or the backing roll 1 is narrow, there is a disadvantage that the side seal plate 20 cannot be inserted into the gap, and even if it can be inserted, Since the side seal plate 20 comes into contact with the surface of the web 2 or the backing roll 1, there is a possibility that problems such as breakage of the web 2 or damage to the surface of the backing roll 1 may occur.

In the conventional apparatus shown in FIG. 9, the rigid plate 24 is slightly separated from the surface of the web 2.
The air boundary layer 21 ′ near the surface of the web 2, which has the fastest flow velocity in a part of the entrained air boundary layer 21 on the surface of the web 2
However, it passes under the rigid plate 24. Also, since there is a distance between the rigid plate 24 and the position where the coating liquid film 3 is in contact with the surface of the web 2, the entrained air boundary layer on the surface of the web 2 reappears during this time. After arranging the rigid plate 24 for removing entrained air for these reasons,
There is a possibility that the layer of the coating liquid film 3 formed on the web surface is disturbed by the entrained air boundary layer 21 on the surface of the web 2 and the degree of improvement in coating quality is reduced. The present invention has been proposed to solve the above-mentioned conventional problems.

[0008]

SUMMARY OF THE INVENTION Therefore, the present invention is based on paper,
Paint,
In an apparatus for applying a liquid coating liquid such as a photosensitive agent by a nozzle or the like, means for detecting a film thickness of a coating liquid film, means for comparing and calculating the detected value with previously input film thickness data, And means for controlling the ejection angle and / or the amount of ejected air of the air nozzle provided on the upstream side of the coating liquid nozzle based on the above. Oh Ru. The present invention also provides an apparatus for applying a liquid coating liquid such as a coating material or a photosensitive agent to a surface of a web such as paper, a steel plate, or a plastic sheet by using a nozzle or the like. only set an elastic flat plate in contact with the web on the upstream side of the coating solution the web running direction upstream side of the (free) table
The surface should always flow down in contact with the elastic plate.
Made of Te, it is an unit for which a problem solution.

[0009]

[Function] In order to form a stable coating liquid film corresponding to the coating conditions, it is simple and effective to use a nozzle that can change the air jet direction arbitrarily and change the landing angle of the jet air on the web surface. It is a strategic measure. As a result, in the actual operation, it is necessary to change the distance between the coating liquid nozzle and the web, the angle formed by the coating liquid nozzle with the web, or when there is a change in the coating liquid flow rate, the web speed, etc. Also, by changing the ejection angle of the air ejection nozzle (and, in some cases, also the ejection air), it is possible to create an optimum state for stabilizing the forming liquid film.

As described above, the air ejection from the air ejection nozzle
With a structure that allows the angle to be adjusted, it is
Air collision angle, size of reduced pressure space formed between coating liquid film
To minimize the amount of wake air in the material to be treated, or
Easily control the degree of decompression in the decompression space and the stability of decompression to appropriate values.
I can control. As a result, a stable coating film can be formed,
Detects the state of the coating film and adjusts the air ejection angle of the nozzle.
It can be controlled optimally.

According to the second aspect of the present invention, the coating liquid is discharged.
Contact the web on the upstream side of the tip of the outlet of the outlet nozzle
Elastic flat plate, so that the coating liquid is
The side (free) surface always flows down in contact with the elastic flat plate
I do. Therefore , the entrained air boundary layer on the web surface is blocked by the elastic flat plate, and cannot enter the free surface of the coating liquid film and the position where the coating liquid film contacts the web surface. Also, since the coating liquid film flows along the back of the elastic flat plate in the web running direction, the position where the elastic flat plate is in contact with the surface of the web,
No space is formed between the position where the coating liquid film contacts the surface of the web, and there is no redevelopment of the entrained air boundary layer. Therefore, a stable coating liquid film is formed on the surface of the web, and the coating quality is improved.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a first embodiment of the present invention; FIG. In addition,
In the present invention, the same parts as those of the prior art will be described using the same reference numerals. In the figure, 1 is a backing roll, 2 is a web, 3 is a coating liquid film, 5 is a coating liquid nozzle, 6
Are air nozzles, which are the same as those shown in FIG. 11 is a rotary air ejection nozzle, 12 is a coating film thickness measuring instrument, 13 is a control unit, 14 is a control valve,
Reference numeral 15 denotes a driving device. FIG. 2 shows a detailed view of a main part (the tip of the coating liquid nozzle) in FIG. In FIG. 2, the coating liquid is supplied from a coating liquid jet nozzle 5 ′ constituting the tip of the coating liquid nozzle 5 to an appropriate angle α and a distance d (typically 0.2 to 1 mm) that can achieve high quality coating on the web 2. ) Is spouted. The web 2 (a flat plate is shown in the figure, but may follow the curvature of the backing roll 1) runs in the direction of the arrow. At the tip of the air nozzle 6 connected to the rear side of the coating liquid nozzle 5, a rotary air jet slit nozzle 11 capable of changing the air jet direction with respect to the web 2 is provided. Although not shown, the rotary air ejection nozzle 11 has shaft portions at both ends so that the air ejection direction can be set at an appropriate angle by using a driving device 15 such as a small motor. When coating on an iron plate, generally, a coating of 5 to 50 μm in thickness is performed with a dry coating film, and the coating speed is 30 to 1 μm.
It is about 50 m / min. When the nozzle of the present invention shown in FIG. 2 is used, the coating liquid amount necessary for coating is uniformly sprayed from the coating liquid jet nozzle 5 ′ in the width direction of the web 2, supplied, and coated. In particular, it is not necessary to smooth the coating with a blade or the like. At the time of coating, first, the angle of the coating liquid nozzle 5 and the interval between the webs 2 are set so that the amount of air is appropriate for the properties of the coating liquid and the coating conditions. The condition of the coating air jet nozzle 11 is adjusted so that coating defects and nonuniform coating liquid film thickness do not occur. However, ultimately, all the conditions including the optimal amount of air to be blown out for forming a coating film are set more easily than before, and a stable coated surface is formed, so that a high quality product can be obtained. Here, as shown in FIG. 1, the coating film quality is scanned by a coating film thickness measuring device (an existing measuring device such as an infrared spectroscopic absorption method) 12 installed behind the coating liquid nozzle 5, The state of coating film formation is determined by detecting the film thickness, and the nozzle condition (nozzle angle and / or jet air amount) is controlled to an optimum value by a correlation function with a preset nozzle angle and air amount. The control unit 13 processes a signal from the measuring device 12 and controls a driving device 15 including a valve 14 for changing an amount of air jetted from the air jet nozzle 11 and a servomotor for changing an angle of the air jet nozzle 11. .

Next, a second embodiment shown in FIGS. 3, 4 and 5 will be described. On the web 2 wound around the backing roll 1 and conveyed, at an arbitrary position on the circumference of the backing roll 1 , The coating liquid 3 ′ from the coating liquid nozzle 5
Spray. On the other hand, the air nozzle 6 is moved to the web of the coating liquid nozzle 5 so that the coating liquid film 3 discharged from the coating liquid nozzle 5 blows an air jet toward the vicinity of a position where the coating liquid film 3 comes into contact with the surface of the web 2 or the backing roll 1. 1 is disposed either upstream (FIG. 4) or downstream (FIG. 3) in the traveling direction. In addition,
The arrangement position of the air nozzle 6 is such that when the coating liquid film 3 discharged from the coating liquid nozzle 5 is bent by the air jet and then falls downward due to gravity, the coating liquid film 3 is returned to the surface of the web 2 or the backing roll 1. Install in a position where contact is difficult. The conditions under which the coating liquid film 3 discharged from the coating liquid nozzle 5 does not contact the surface of the web 2 or the backing roll 1 and the air jet from the air nozzle 6 sufficiently exerts the coating width regulating function are as follows. For example, the coating liquid jet flow velocity is 1.0 m / sec,
When the coating liquid jet thickness is 0.3 mm and the coating liquid jet angle is about 60 ° with respect to the tangent line in the web running direction at the position where the coating liquid normally contacts, the air jet flow velocity is 10 m /
The air jet may be set so that the air jet thickness is 5 mm, the air jet angle and the web tangent at the position where the coating liquid contacts the web are parallel.

The coating liquid film 3 that has not adhered to the surface of the web 2 or the backing roll 1 as described above flows downward by the action of gravity. Further, a part of such a coating liquid becomes a mist and scatters downstream of the air jet due to fluid friction generated between the coating liquid and the air jet. In order to collect the coating liquid that has not adhered to the surface of the web 2 or the backing roll 1, a pan 17 is provided in a direction in which the coating liquid 3 'flows down or scatters. The coating liquid 3 ′ collected in the pan 17 is recirculated by a suitable known means and discharged again from the coating liquid nozzle 5. In addition, the arrangement of the coating liquid nozzle 5 and the air nozzle 6 in FIGS. 3 and 4 is upside down, and the air nozzle 6 is disposed downstream in the web running direction in FIG. 3 and upstream in FIG. Although it is arranged,
In any case, the coating liquid ejection direction and the air ejection direction are the same. This is to increase the air pressure acting on the coating liquid jet by blowing air into the wedge-shaped space formed between the coating liquid jet and the web surface, so that the coating liquid contacts the web surface. It is for preventing effectively. Also, when the angle between the coating liquid discharge direction and the web surface is a right angle or close to a right angle, this is not limited,
When the coating liquid that has been removed by the blowing air and has not adhered to the web surface falls vertically downward due to gravity, it does not re-adhere to the surface of the web 2 and can be collected efficiently. An air nozzle may be provided so that air is ejected to the air. FIG. 5 shows the coating liquid nozzle 5, the web 2, and the air nozzle 6.
The following shows the positional relationship between them. The coating width is controlled by rotating a pinion gear 18 ′ connected to a rack 18 connected to the coating liquid nozzle 5 with an electric motor or the like to move the air nozzle 6 in the width direction of the web 2. It has become.

Next, a description will be given of a third embodiment of the present invention with reference to FIG. 6. In the tip of the lips 5 a and 5 b serving as the discharge ports of the coating liquid film 3, the nozzle 5 is located upstream of the web 2 in the traveling direction.
At the tip of b, an elastic flat plate 19 is provided so that the coating liquid continuously falls on the coating liquid flow path surface 5b 'of the nozzle 5b.
The conditions for disposing the elastic flat plate 19 satisfy the following conditions. That is, the tip of the lip 5b has a sharp edge so that a step does not occur at the joint between the coating liquid flow path surface 5b 'of the lip 5b and the coating liquid flow lower surface 19' on the elastic flat plate 19. Further, the length of the elastic flat plate 19 is such that after the elastic flat plate 19 is bonded to the outer surface of the lip 5b by an appropriate bonding method such as an adhesive, the tip of the elastic flat plate 19 is at least in contact with the surface of the web 2, or more. Length. Further, the elastic flat plate 19 follows a change in the surface shape of the web 2 (such as unevenness), but foreign matter such as dust on the surface of the web 2 is removed by the coating liquid film 3 and the surface of the web 2. A material having rigidity that can be eliminated so as not to enter the contact portion and that has a high smoothness on the lower surface of the coating liquid film 3 (for example, synthetic paper such as ceramic coated paper or a Teflon sheet) is used.

When the elastic plate 19 is provided so as to satisfy the above conditions, the entrained air boundary layer developed on the surface of the web 2 with the movement of the web 2 causes the coating liquid film 3 and the surface of the web 2 to come into contact with each other. And collide with the elastic flat plate 19 on the upstream side in the web movement direction at the position where the elastic plate 19 moves. At this time, the rigidity of the elastic plate 19 is determined by the dynamic pressure of the entrained air boundary layer and the air layer penetrating into the wedge-shaped space formed between the elastic plate 19 and the surface of the web 2 in accordance with the theory of fluid lubrication. The entrained air boundary layer on the surface of the web 2 is completely shut off by the elastic flat plate 19, since the entrained air is not deformed by the fluid pressure or the like. On the other hand, since the coating liquid film 3 flows down along the surface corresponding to the back surface with respect to the surface of the elastic flat plate 19 against which the entrained air boundary layer collides, the entrained air boundary layer on the surface of the web 2 causes The web 2 without impeding the flow of the coating liquid film 3
And a stable coating liquid film 3 on the surface of the web 2
To form When ceramic coated paper is used for the elastic flat plate 19, the elastic flat plate 19 is hardly worn even when it comes into contact with the web 2, and has excellent durability and stable coating quality over a long period of time. Further, in the embodiment of FIG. 6, the coating speed, the shape and size of the elastic flat plate 19, the distance between the object to be coated and the nozzle are not particularly limited. Construction speed 30
0m / min, elastic flat plate width 500mm, length 10m
m, a thickness of 0.2 mm, and a distance of 2.0 mm from the article to be coated to the nozzle, the effect of removing the air entrained web was confirmed.

[0017]

According to the present invention, as described in detail above, it is possible to provide a non-contact type coating liquid nozzle which can easily cope with changes in coating conditions and realize high quality coating. In other words, effective removal of the air flowing along the web, uniformization of the coating liquid film by stabilizing the reduced pressure space, and highly accurate coating tolerance can be achieved by a simple operation. In addition, since the stable film coating state can be controlled online, the quality of the product can be stabilized, and the economic loss due to defective coating can be reduced. Further, since the nozzle portion is miniaturized, the structure of the coating portion is simplified and maintenance is easy. Also, the web running direction of the coating liquid
The upstream (free) surface always flows down in contact with the elastic plate
Since, it eliminated the coating failure due to entrained air boundary layer generated on the surface of the web, a stable and high-quality coating material can be supplied. Further, foreign substances such as dust existing on the web surface are removed, and the web surface can be cleaned.

[Brief description of the drawings]

FIG. 1 is a side view of a coating apparatus showing a first embodiment of the present invention.

FIG. 2 is a detailed view of a main part in FIG.

FIG. 3 is a side sectional view of a coating apparatus showing a second embodiment of the present invention.

FIG. 4 is a side cross-sectional view of FIG. 3 in a case where the ejection directions of a coating liquid nozzle and an air nozzle are upside down.

FIG. 5 is a front view of FIG. 4;

FIG. 6 is a side sectional view of a coating apparatus showing a third embodiment of the present invention.

FIG. 7 is a side sectional view showing an example of a conventional coating apparatus.

FIG. 8 is a side sectional view showing another example of the conventional coating apparatus.

FIG. 9 is a side sectional view of a coating apparatus different from each of the conventional examples.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 backing roll 2 web 3 coating liquid film 3 ′ coating liquid 5 coating liquid nozzle 5 ′ coating liquid jet nozzle 6 air nozzle 11 rotary air jet nozzle 12 coating film thickness measuring device 13 control unit 14 control valve 15 Drive 17 Pan 18 Rack 18 'Pinion 19 Elastic flat plate

Claims (2)

(57) [Scope of request for utility model registration] 1. An apparatus for applying a liquid coating liquid such as a paint or a photosensitive agent to a surface of a web such as paper, a steel plate, or a plastic sheet by a nozzle or the like, and a means for detecting a film thickness of the coating liquid film; Means for comparing and calculating the detected value and the previously input film thickness data; and means for controlling the jet angle and / or jet air amount of the air nozzle provided on the upstream side of the coating liquid nozzle based on the result of the calculation. A coating apparatus characterized in that: 2. An apparatus for applying a liquid coating liquid such as a coating material or a photosensitive agent to a surface of a web such as paper, a steel plate, or a plastic sheet by a nozzle or the like. An elastic flat plate in contact with the web is provided on the upstream side of the
A coating device which flows down while being in contact with said elastic flat plate .