JP2006122812A - Coater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coater in which liquid granules to be defoamed is capable of retaining a sufficient mass to generate sufficiently large impact strength by jetting a coating liquid through a nozzle in a continuous liquid film state. <P>SOLUTION: In the coater to coat a sheet-like material S with the coating liquid 12, it is provided with a deaerator 4 comprised of a vacuum vessel 11 and a liquid film forming nozzle 14 to collide the coating liquid 12 against the inner wall face 11o of the vacuum vessel 11 so that the continuous liquid 13 film forms. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coating apparatus for coating an aqueous coating solution on a sheet-like material such as paper, a polymer film, or a metal foil.

  In a facility that applies liquid to the surface of a sheet such as paper, polymer film, or metal foil, and then dries, it is mixed with aqueous liquid and raw materials that are produced for the purpose of applying to the sheet. It is widely known that the air to be contained is in the form of microbubbles, and it is common to apply the liquid as it is to a sheet and use it after drying.

  In many cases, the sheet is paper, and the coating device is also an excess of paint so that it can be applied according to the purpose immediately after applying a large amount of paint to the sheet, as represented by air knife coater and blade coater head. A method of scraping off is generally used. This method has a large amount of application per unit area and relatively low application accuracy. Therefore, it is possible to increase the application speed, which is suitable for mass production and widely used. In this case, the air contained in the coating solution cannot be a problem because the thickness of the coating film is large.

  The air contained in the coating liquid may be a problem depending on the type of the sheet to be coated or may be ignored, and generally cannot be a problem when the sheet to be coated is paper. That is, in the case of paper, many are porous, water-absorbing, and since the surface is microscopically uneven, minute air content does not appear on the coated surface and is regarded as a problem. There are few things. However, in the case of a polymer film, contrary to paper, there is no water absorption and there are few surface irregularities, so minute bubbles in the paint appear on the coated surface, and many are judged as defective products. The

  The microbubbles contained in the coating solution described above are mainly used when a water-based paint is applied to the surface of a polymer film or metal foil. The removal of various bubbles has been a bigger problem for the sheet coating industry. For such coating, a coating device such as a curtain coater, a fountain coater, or a die coater is preferably used.

  That is, if microbubbles are generated on the surface of the coated sheet, many cannot be shipped as a product in terms of quality. For this reason, the producers provided a continuous vacuum defoaming machine during the paint manufacturing process for the purpose of removing the contained air bubbles in the coating liquid as a means for preventing the generation of fine bubbles on the sheet application surface. The air in the liquid was evacuated and the processed liquid was sent to the coating equipment.

  Considering the above-mentioned continuous vacuum degassing machine in principle, the liquid to be defoamed is put into a vacuum vessel, and the microbubbles in the liquid are expanded and destroyed, and the same liquid is flowed to the inner wall of the vessel. I thought that it was divided roughly into two kinds of principle of the impact destruction defoaming method which destroys by raising and colliding. Many continuous vacuum defoamers are thought to use either principle as a result.

  In the vacuum defoaming method, the defoamed liquid is dispersed in the form of droplets for the purpose of expanding the surface area of the liquid in order to remove bubbles in the defoamed liquid, and dispersed in the vacuum. The vacuum defoaming machine that is currently being implemented will be described with reference to FIG. 6. A motor (b) is installed in the upper center outside the vacuum vessel (b). The rotating shaft (c) of the motor (b) is inserted into the vacuum vessel (a) via the mechanical seal (d), and a number of small holes (e) are drilled at the tip of the rotating shaft (c). The installed rotating cylinder (f) is attached so that it can rotate as a unit, and the liquid to be defoamed is injected into the rotating cylinder (f) by the liquid injection tube (g) inserted into the vacuum vessel (b). Due to the centrifugal force of the cylinder (f), the liquid is splashed into the vacuum from the small hole (e). In this case, the small hole (e) to be machined into the rotating cylinder (f) cannot be made too small due to machining, and the diameter is 0. 5 mm to 1. Since it is about 0 mm, the particle diameter of the defoamed liquid that scatters in the form of droplets is approximately the same.

In addition, another method of impact defoaming, which is a defoaming method, is that the liquid to be defoamed is subjected to centrifugal force by the above-mentioned rotating cylinder (f) to collide with the inner wall of the vacuum vessel (ii), and the impact Is a method of destroying water droplets and extracting the air inside, and the impact force is generally obtained by the following equation.
E = MV ²
However, E is impact energy, M is mass, V is speed.
The impact energy E is increased by causing a larger mass M to collide at a higher speed. Incidentally, the mass M in this impact fracture defoaming method is the weight of the defoamed liquid particles, and the speed V refers to the speed at which the defoamed liquid particles collide with the inner wall of the vacuum vessel.

  In the above conventional vacuum defoaming machine, the microbubbles in the defoamed liquid in question have a diameter of 0.05 mm to 0.1 mm, so that the wall thickness of one water droplet is more than 10 times the air bubble diameter. There is a disadvantage that the water droplet wall cannot be broken only by the expansion of bubbles in vacuum. Also, this vacuum defoaming machine needs to reduce the size of the defoamed liquid particles due to the destruction principle of the vacuum defoaming method described above, and is very small in mass, and the collision speed is the centrifugal speed of the rotating cylinder. Since the speed is obtained by force, it has a disadvantage that it is relatively small and cannot generate a sufficient impact force. Further, as described above, a motor is installed outside the vacuum vessel, and the rotation shaft of this motor is set inside the vacuum vessel. The structure is equipped with a rotating cylinder provided with a large number of small holes at the tip of the rotating shaft. It will be something.

  As a result of intensive studies to overcome the above-described problems, the present invention does not make the liquid to be defoamed into a water droplet mist in the vacuum container as in the prior art, but injects it in a continuous liquid film state by a nozzle, It is an object of the present invention to provide a coating apparatus having a deaeration device in which defoamed liquid particles have a sufficient mass and can generate a sufficiently large impact force.

  Means for solving the above problems will be described with reference numerals in the embodiments described later. The invention according to claim 1 is the application of the coating liquid 12 to the sheet material S in the vacuum container 11. And a deaeration device 4 which is disposed in the vacuum vessel 11 and includes a liquid film forming nozzle 14 which jets and collides the coating liquid 12 against the inner wall surface 11o of the vacuum vessel so as to form a continuous liquid film 13. It is provided.

  A second aspect of the present invention is the coating apparatus according to the first aspect, wherein the liquid film forming nozzle 14 collides the continuous liquid film 13 with the inner wall surface 11o of the vacuum vessel substantially perpendicularly. .

  A third aspect of the present invention is the coating apparatus according to the first or second aspect, wherein the continuous liquid film 13 ejected from the liquid film forming nozzle 14 has a fan shape or a circular shape.

  According to a fourth aspect of the present invention, in the coating apparatus according to any one of the first to third aspects, the film thickness of the continuous liquid film 13 sprayed from the liquid film forming nozzle 14 is 100 to 500 μm.

  According to a fifth aspect of the present invention, in the coating apparatus according to any one of the first to fourth aspects, a plurality of the liquid film forming nozzles 14 are respectively disposed opposite to the inner surface 11o of the vacuum vessel and spaced apart from each other. It is characterized by that.

  A sixth aspect of the present invention provides the coating apparatus according to any one of the first to fourth aspects, wherein a plurality of the liquid film forming nozzles 14 are disposed so as to face the inner wall surface 11o of the vacuum vessel and at intervals in the circumferential direction. It is characterized by becoming.

  Claim 7 is the coating device according to any one of claims 1 to 6, wherein at least two cushion tanks 5 and 6 are arranged in parallel on the front side of the deaeration device 4, The coating liquid 12 received from the coating liquid receiving port 24 is pressurized by the pressure air supplied into the cushion tanks 5 and 6 and discharged from the coating liquid discharge port 25. 6 is alternately operated, the coating liquid 12 is alternately discharged from the coating liquid discharge ports 25 and 25 of both the cushion tanks 5 and 6, and the pressurized coating liquid is supplied to the liquid film forming nozzle 14 side of the deaeration device 4. 12 is continuously fed.

  The effect of the invention by the above-described solution means will be described with reference numerals in the embodiments described later. The coating apparatus of the invention according to claim 1 includes a vacuum container 11 and a coating liquid 12 in the vacuum container 11. Is provided with a degassing device 4 equipped with a liquid film forming nozzle 14 that is jetted and collided so as to form a continuous liquid film 13 on the inner wall surface 11o of the vacuum vessel. Since the diameter of the liquid droplet of the coating liquid 12 is significantly larger than that of the conventional water droplet mist and the mass of the liquid particle is increased, the impact breaking force of the bubbles contained in the coating liquid 12 Therefore, the deaeration action can be effectively exerted accordingly.

  Further, since the degassing device 4 is merely provided with the liquid film forming nozzle 14 in the vacuum vessel 11, the structure can be greatly simplified as compared with the conventional continuous vacuum deaerator, and the production cost can be reduced. Not only can the cost be significantly reduced, but driving equipment such as a motor for driving the rotating cylinder is not required, so that the running cost can be greatly reduced, and the vacuum vessel 11 can be greatly reduced in size. The entire deaeration device 4 can be reduced in size and size.

According to the invention of claim 2, by causing the continuous liquid film 13 to collide with the inner wall surface 11o of the vacuum vessel 11 substantially perpendicularly, the impact breaking force of the bubbles when colliding with the inner wall surface 11o of the vacuum vessel. Becomes the largest, and the deaerating effect can be exhibited more effectively.

  As described in claim 3, the continuous liquid film 13 ejected from the liquid film forming nozzle 14 is preferably fan-shaped or circular.

  As described in claim 4, the film thickness of the continuous liquid film 13 ejected from the liquid film forming nozzle 14 is preferably 100 to 500 μm, and if the film thickness is in the range of 100 to 500 μm, bubbles 19 is located near the surface side of the liquid film 13 and easily expands due to a vacuum action, and also easily breaks when colliding with the vertical inner wall surface 11o.

  As described in claim 5, by providing a plurality of liquid film forming nozzles 14 facing the inner wall surface 11o of the vacuum vessel and spaced apart from each other in the vertical direction, it is possible to increase the deaeration processing capability. .

  As described in claim 6, by disposing a plurality of liquid film forming nozzles 14 facing the inner wall surface 11o of the vacuum vessel and spaced apart in the circumferential direction, the deaeration capacity can be increased. it can.

  As in the invention according to claim 7, by arranging at least two cushion tanks 5 and 6 side by side on the front side of the deaeration device 4 and operating both the cushion tanks 5 and 6 alternately, A normal pressure coating liquid 12 having no pulsation can be supplied to the liquid film forming nozzle 14 to form a continuous liquid film 13 suitable for defoaming.

  A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall schematic view showing the entire coating apparatus, FIG. 2 is an enlarged longitudinal sectional view of a deaeration device in the coating apparatus, and FIG. FIG. 3 is a cross-sectional view taken along line XX in FIG. 2, and FIG. In FIG. 1, 1 is a coating liquid tank, 2 is a coater head, 3 is a coarse bubble separator that removes only relatively large bubbles in the liquid to be defoamed, and 4 is a detachment that forms an important part of the coating apparatus according to the present invention. The first cushion tank 5 and the second cushion tank 6 that supply the coating liquid 12 to the deaeration device 4 under pressure are arranged in parallel on the front side of the deaeration device 4.

  In the coating apparatus according to this embodiment, when the air contained in the coating liquid can be almost ignored as in the case where the sheet S to be coated is paper, the coating liquid in the coating liquid tank 1 is pressurized by the pump P1 to generate coarse bubbles. The coating liquid fed from the separator 3 to the coater head 2 is applied to the coated sheet S supported by the backup roll 9 by the fountain 7 via the contact roll 8. When the coating sheet S is, for example, a polymer film, when the air contained in the coating solution becomes a problem, the coating solution pressurized by the pump P1 is removed from the coarse bubble separator 3 to the deaerator 4 side. The deaeration device 4 sufficiently deaerates and returns to the coating liquid tank 1. A filter 10 is provided on the front side of the coarse bubble separator 3.

  The structure of the deaeration device 4 will be described in detail. The deaeration device 4 is arranged in the vacuum vessel 11 and the vacuum vessel 11 as shown in FIG. It comprises a liquid film forming nozzle 14 for spraying and colliding with the inner wall surface 11o so as to form a continuous liquid film 13, and a suction port 17 provided at the upper part of the vacuum vessel 11 is an air suction tube. 15 is connected to a vacuum pump 16, and the operation of the vacuum pump 16 sucks the inside of the vacuum container 11 and keeps it in a vacuum state. Reference numeral 18 denotes a motor for driving the vacuum pump P2.

  As can be seen from FIG. 2, the vacuum vessel 11 includes a main body cylindrical portion 11a, a main body taper portion 11b, and a lid portion 11c. The lid portion 11c is provided with a suction port 17, and a liquid film is formed on the main body cylindrical portion 11a. A nozzle 14 is attached, and a pump P2 for discharging the coating liquid is connected to the lower portion of the main body taper portion 11b. The liquid film forming nozzle 14 is supplied with the coating liquid 12 pressurized by the first cushion tank 5 and the second cushion tank 6 from the pipe g. Although illustration is omitted, since the inside of the vacuum vessel 11 is in a vacuum state, the liquid easily evaporates, dirt easily adheres to the inner wall surface, and cleaning is impossible during operation. An inner covering layer made of a fluorine compound is formed on the inner wall surfaces of the portion 11a, the main body taper portion 11b, and the lid portion 11c, thereby preventing the adhesion of dirt.

  The liquid film forming nozzle 14 has a well-known structure per se and is commercially available. However, the liquid film forming nozzle 14 does not eject the liquid in a mist form like a spray nozzle, but forms a continuous liquid film 13 on a predetermined ejection surface. As shown in FIG. 2 and FIG. 3 (a), the nozzle to be formed is attached to the main body cylindrical portion 11a of the vacuum vessel 11, and is a fan-shaped liquid that is continuous with respect to the opposing vertical inner wall surface 11o. The coating liquid 12 is sprayed so as to form the film 13 and collides with the vertical inner wall surface 11o vertically. FIG. 3B is an enlarged view of a state in which the continuous liquid film 13 collides perpendicularly with the vertical inner wall surface 11o.

  The operation of the deaeration device 4 configured as described above will be described. In the vacuum vessel 11, the internal air is sucked by the vacuum pump 16 and kept in a vacuum state, and the vacuum vessel 11 in this vacuum state A pressurized coating solution 12 is supplied from a pipe g to a liquid film forming nozzle 14 provided inside. As shown in FIGS. 2 and 3, the coating liquid 12 sprayed by the liquid film forming nozzle 14 forms a continuous liquid film 13 on the vertical inner wall surface 11o in a vacuum, as shown in FIGS. As shown in b), it collides with the vertical inner wall surface 11o and flows down along the inner wall surface 11o to the lower side of the vacuum vessel 11.

In this case, when the coating liquid 12 forms the continuous liquid film 13, the diameter of the liquid droplet of the coating liquid 12 becomes much larger than that of the conventional water droplet mist, and the mass of the liquid droplet increases. Thus the mass of the increased liquid particle collides with the vertical inner wall surface 11o of the vacuum chamber 11, as can be seen from the equation E = MV ² as described above, if the velocity V of the liquid particle is constant, the mass M is large Droplet Since the impact energy E at the time of collision increases, the impact breaking force of the bubbles contained in the coating liquid 12 is large, and therefore, the deaeration action can be effectively exhibited as much. Further, from the equation E = MV ² , the pressure of the coating liquid 12 supplied to the liquid film forming nozzle 14 is increased to increase the spraying speed of the coating liquid 12 by the liquid film forming nozzle 14, thereby causing the impact destruction of the bubbles. The power can be further increased. The injection speed was about 20 m / second in the example of the embodiment. This is because the pressure that is easy to use as the air pressure prepared for instrumentation in factories and the like is up to about 390 kPa (4 kg / cm ² ), the diameter of the vacuum vessel is 350 mm, and the processing flow rate of the coating liquid is 7 L / min. It was an appropriate value. In the present invention, it is very preferable to reach the wall surface while maintaining the state of the continuous liquid film. For that purpose, it is necessary to set the spraying speed to a certain level or more, but the spraying speed is determined by the pressure applied to the coating liquid to be used, the coating liquid processing flow rate, the design of the liquid film forming nozzle to be used, etc. In maintaining it, the size and shape of the vacuum vessel have a great influence, so it is difficult to determine them in general. However, if economics are ignored, it can be said that the faster the injection speed, the better.

  Further, it has been experimentally found that the film thickness of the continuous liquid film 13 injected into the vacuum by the liquid film forming nozzle 14 is preferably 100 to 500 μm. If the film thickness is in the range of 100 to 500 μm, as shown in FIG. 3B, the bubble 19 is located near the surface side of the liquid film 13 and is easily expanded by the vacuum action. This is because it becomes easy to break when colliding with the vertical inner wall surface 11o. On the other hand, if the film thickness is 500 μm or more, the internal bubbles 18 are difficult to expand and are difficult to break, and the defoaming effect is deteriorated. If the film thickness is 100 μm or less, the liquid film 13 is torn, This is because it becomes water droplets. This film thickness means the film thickness of the continuous liquid film immediately before collision with the wall of the vacuum vessel. In addition, although a thick continuous liquid film becomes thin like this immediately after jetting, the present inventors set the jetting status of the coating liquid (viscosity of about 200 cp) and water having a lower viscosity (viscosity of 10 cp) under atmospheric pressure. Although observed under vacuum, it was also found that the degree of change was almost unchanged under atmospheric pressure and under vacuum.

  The liquid film forming nozzle 14 is preferably attached so that the continuous liquid film 13 collides with the vertical inner wall surface 11o of the vacuum vessel 11 vertically as shown in FIG. This is because when the continuous liquid film 13 collides perpendicularly with the inner wall surface 11o of the vacuum vessel 11, the impact force is greatest, and the impact angle increases as the opposing angle of the liquid film 13 to the inner wall surface 11o becomes smaller than 90 °. This is because power is weakened. As the impact force increases, the impact destructive force of the bubbles increases accordingly, and the deaeration action can be more effectively exhibited.

  In the vacuum container 11 of the embodiment shown in FIG. 2, one liquid film forming nozzle 14 is provided inside the vacuum container 11, but the vacuum container 11 of the embodiment shown in FIGS. 4 (a) and 4 (b). As described above, a plurality of, for example, three liquid film forming nozzles 14 may be disposed so as to face the inner wall surface 11o of the vacuum vessel and be spaced apart vertically. In this case, it is preferable to dispose the three liquid film forming nozzles 14 in the circumferential direction so that the liquid film forming nozzles 14 at each stage do not overlap in the vertical direction.

  Although not shown, a plurality of liquid film forming nozzles 14 may be arranged in the same plane. In that case, it is necessary to prevent the continuous liquid films 13 formed by being ejected from the respective liquid film forming nozzles 14 from colliding with each other.

  By installing a plurality of liquid film forming nozzles 14 in one vacuum vessel 11 as described above, it is possible to increase the defoaming capacity of the coating liquid 12 according to the number of liquid film forming nozzles 14 installed. .

  The processing capacity of the conventional continuous vacuum deaerator shown in FIG. 6 is determined by the diameter of the rotating cylinder (f) provided in the vacuum vessel (a). That is, the diameter of the rotating cylinder (f) increases in proportion to the processing amount of the defoamed liquid (coating liquid). The reason for this is that, as described above, a plurality of small holes (e) are processed in the rotating cylinder (f) for the purpose of splashing liquid droplets, and the number of holes needs to be changed depending on the amount of processing. Since the flow rate that can pass through the small holes (e) is a specific value depending on the concentration and viscosity of the liquid, the diameter of the rotating cylinder (f) increases when the processing amount is increased. In addition, the vacuum vessel (b) having the rotating cylinder (f) also has a larger diameter of the vacuum vessel (b) due to the increase in the diameter of the rotating cylinder (f). In other words, the external shape of the conventional continuous vacuum deaerator is determined by the processing capacity.

  On the other hand, the deaeration device 4 according to the present invention is based on the knowledge that the size of the vacuum vessel 11 is not originally related to the processing capacity, so that the vacuum vessel 11 having one liquid film forming nozzle 14 is used. Thus, when the number of the liquid film forming nozzles 14 is increased to a plurality, it has been found through experiments that the processing capacity increases according to the number of the liquid film forming nozzles 14 as described above.

  Also, the liquid film forming nozzle 14 provided in the vacuum vessel 11 of the deaeration device 4 shown in FIGS. 2 to 4 applies the coating liquid so as to form a continuous fan-shaped liquid film 13 on the inner wall surface 11o. In FIG. 5, the liquid film forming nozzle 14 is provided downward in the center of the lid portion 11 c of the vacuum vessel 11, and has a circular shape in plan view with respect to the inner wall surface 11 o of the vacuum vessel 11. An embodiment in which the coating liquid 12 is sprayed so as to form a continuous liquid film 13 is shown.

  2 to 5, the liquid film forming nozzle 14 is provided in the vacuum container 11 so as to form a continuous liquid film 13 having a fan shape on a plan view on the inner wall surface 11o of the vacuum container 11. Although attached, the liquid film formation nozzle 14 may be installed so as to form a fan-shaped liquid film 13 in front view (or side view) with respect to the inner wall surface 11o of the vacuum vessel 11. However, when the liquid film forming nozzle 14 is installed so as to form the fan-shaped liquid film 13 in front view (or side view) with respect to the inner wall surface 11o as described above, the vacuum vessel 11 becomes unnecessarily long. As shown in the embodiment shown in FIGS. 2 to 5, the liquid film forming nozzle 14 is installed so as to form a continuous liquid film 13 having a fan shape or a circular shape in plan view on the inner wall surface 11 o of the vacuum vessel 11. Thus, a plurality of liquid film forming nozzles 14 can be used, and the length of the vacuum vessel 11 can be made as short as possible.

  Moreover, since the deaeration device 4 according to the present invention described above is merely provided with the liquid film forming nozzle 14 in the vacuum vessel 11, the structure is compared with the conventional continuous vacuum deaerator shown in FIG. The manufacturing cost can be significantly reduced and the driving cost such as a motor for driving the rotating cylinder is not required, and the running cost can be greatly reduced. Further, from the viewpoint that the size of the vacuum vessel 11 is not related to the processing capacity as described above, the vacuum vessel 11 is also greatly reduced in size, and the entire deaeration device 4 can be reduced in size.

The table below shows the results of a comparative test between the deaeration device 4 described above and a conventional continuous vacuum deaerator. (Test method) Using the deaerator shown in FIG. 2 and the conventional continuous vacuum deaerator shown in FIG. 6, the air in the vacuum vessel 11, (a) is evacuated by a vacuum pump, and the coating solution The specific gravity of the coating solution obtained by supplying the same amount per unit time to the vacuum vessel 11 (a) was measured, and the larger the specific gravity, the higher the defoaming effect.
(Test conditions) Degree of vacuum: -90 kpa Coating liquid flow rate: 7 l / min Initial liquid specific gravity: 0.88 g / cc

  As a result of the above comparative test, it can be seen that the liquid film forming nozzle type has clearly higher defoaming performance than the rotating cylinder type. In addition, since a rotating cylindrical drop-type scattering device is not required, a motor or the like is not required, and power consumption and facility costs can be kept low.

  Next, referring again to FIG. 1, the entire coating apparatus will be described. In FIG. 1, a is a pipe line connecting the coating liquid tank 1 and the coarse foam separator 3, and b is the coarse foam separator 3. A pipe c connecting the coater head 2, c is a low specific gravity coating liquid 12 containing foam that has passed through the coarse bubble separator 3 from the pipe a to the receiving three-way valve 20 side in front of the cushion tanks 5, 6. The pipe to be fed, d is a pipe connecting the receiving three-way valve 20 and the cushion tanks 5 and 6, and has a receiving pipe line e1 and a receiving two-way valve 22 on the first cushion tank 5 side having the receiving two-way valve 21. It branches to the receiving pipe line e2 on the second cushion tank 6 side. A discharge three-way valve 23 is provided at the junction of the discharge pipe f1 of the first cushion tank 5 and the discharge pipe f2 of the second cushion tank 6, and is pressurized by the first cushion tank 5 or the second cushion tank 6. The coating liquid 12 is supplied into the vacuum container 11 of the deaeration device 4 from the pipe g through the discharge three-way valve 23. Reference numeral h denotes a pipe line for feeding the coating liquid 12 deaerated by the deaeration device 4 to the coating liquid tank 1 by the coating liquid discharge pump P2. In addition, i is a pipe for returning the coating liquid 12 overflowing at the time of coating in the coater head 2 to the coating liquid tank 1, j is a pipe for supplying a new coating liquid 12 to the coating liquid tank 1 from a storage (not shown), k is a bypass line connecting the receiving two-way valve 22 and the coating liquid tank 1.

  Each of the first and second cushion tanks 5 and 6 pressurizes the coating liquid 12 received from the coating liquid receiving port 24 with the pressure air supplied into the cushion tanks 5 and 6 from the air pipe n, and thereby the coating liquid. By discharging the first cushion tank 5 and the second cushion tank 6 alternately, the first and second cushion tanks 5 and 6 are alternately applied from the coating liquid discharge ports 25 and 25, respectively. The pressure coating liquid 12 is discharged, and the pressure coating liquid 12 is continuously fed from the pipe g to the liquid film forming nozzle 14 of the deaeration device 4. In each air line n connected to the cushion tanks 5 and 6, a pressure-feeding electromagnetic valve SV1 that supplies air of a predetermined pressure to the cushion tanks 5 and 6 and a discharge electromagnetic that discharges air inside the cushion tanks 5 and 6 are provided. A valve SV2 is provided.

  In the use of this coating apparatus, when the coated sheet S can almost ignore the air contained in the coating liquid 12 like paper, the operation of the deaeration device 4 is stopped, and the coating liquid 12 in the coating liquid tank 1 is pumped P1. Is applied to the coater head 2 through the line b through the coarse bubble separator 3 and the coating operation is performed. In this case, the receiving three-way valve 20 is operated so that communication between the pipe c, the pipe d, and the bypass pipe k is prevented. In addition, the pipe line c and the bypass pipe line k are communicated at the time of initial operation when performing the coating operation or at the time of cleaning the pipe line.

  For example, when the coating operation is performed using the coated sheet S in which the air contained in the coating solution causes a problem, such as a polymer film, the degassing device 4 is operated and the degassing device 4 performs the degassing. Do care. In this case, the receiving three-way valve 20 is operated so that the pipe line c and the pipe line d communicate with each other, and the coating liquid pressurized by the pump P1 is supplied to the pipe line a → the coarse bubble separator 3 → the pipe. It is made to feed to the path c-> reception 3 way valve 20-> line d.

  The pipe d is branched into a receiving pipe line e1 on the first cushion tank 5 side and a receiving pipe line e2 on the second cushion tank 6 side. The first cushion tank 5 and the second cushion tank 6 are different from each other. For example, when the first cushion tank 5 side is operated, the receiving two-way valve 21 on the first cushion tank 5 side is opened and the receiving two-way valve on the second cushion tank 6 side is operated. 22 is closed, and when a predetermined amount of coating liquid 12 is supplied into the first cushion tank 5 from the coating liquid receiving port 24, the receiving two-way valve 21 is closed, and the pressure-feeding electromagnetic valve SV1 is opened. Air is pumped into the first cushion tank 5, the coating liquid 12 in the tank 5 is pressurized by the pressurized air and discharged from the coating liquid discharge port 25, and this pressurized coating liquid 12 is discharged from the discharge line f 1 → discharge 3. Pass the way valve 23 → line g It is supplied to the liquid film forming nozzle 14 of the degasser 4. After the application liquid 12 in the first cushion tank 5 is discharged, the discharge three-way valve 23 is closed, the pressure feeding solenoid valve SV1 is closed, and the discharge solenoid valve SV2 is opened. The air is sucked and discharged, and the tank 5 is in a vacuum state and waits for the next supply of the coating liquid 12.

  When the operation of the first cushion tank 5 is thus completed, the second cushion tank 6 continues to operate. That is, when the receiving two-way valve 21 on the first cushion tank 5 side is closed and the receiving two-way valve 22 on the second cushion tank 6 side is opened, the coating liquid 12 enters the second cushion tank 6 from the coating liquid receiving port 24. Is supplied and a predetermined amount is supplied, then the receiving two-way valve 22 is closed, the pressure feeding solenoid valve SV1 is opened, and air is pumped into the second cushion tank 6 from the air line n, and the tank by the pressure air 6 is pressurized and discharged from the coating liquid discharge port 25, and this pressurized coating liquid 12 passes through the discharge line f 2 → the discharge three-way valve 23 → the line g and passes through the liquid in the deaeration device 4. It is supplied to the film forming nozzle 14. After the coating liquid 12 in the second cushion tank 6 is discharged, the discharge three-way valve 23 is closed, the pressure feeding solenoid valve SV1 is closed, the discharge solenoid valve SV2 is opened, and the air in the second cushion tank 6 is opened. Is sucked and discharged, and the inside of the tank 6 is in a vacuum state and waits for the next coating liquid 12 to be supplied.

  As described above, the first cushion tank 5 and the second cushion tank 6 operate alternately to discharge the pressurized coating liquid 12 from the coating liquid discharge ports 25 and 25 of both the cushion tanks 5 and 6 alternately. The pressurized coating liquid 12 can be continuously fed from the pipe g to the liquid film forming nozzle 14 of the degassing device 4 as the defoamed liquid.

  Instead of the two cushion tanks 5 and 6 arranged in front of the deaeration device 4 as described above, one pump is installed, and the application liquid 12 as the defoamed liquid is degassed by this pump. In the case of a pump, when the coating liquid 12 is pulsated during feeding, and the coating liquid 12 is supplied to the liquid film forming nozzle 14 in a pulsating state, the continuous liquid This adversely affects the formation of the film 13. In this regard, the first cushion tank 5 and the second cushion tank 6 are juxtaposed, and the two cushion tanks 5 and 6 are alternately operated, whereby a normal pressurized coating liquid 12 having no pulsation can be obtained. A continuous liquid film 13 suitable for defoaming can be formed by supplying to the film forming nozzle 14. In this embodiment, the first and second cushion tanks 5 and 6 are arranged side by side. However, at least two cushion tanks may be arranged side by side, and two or more cushion tanks can be arranged side by side. .

  Moreover, in the coating device of the embodiment described above, the coarse bubble separator 3 and the deaeration device 4 are arranged in parallel, and the deaeration device 4 is operated only when necessary. It is good also as a coating device which provided only the deaeration apparatus 4 without providing. A coating apparatus or the like configured to defoam the entire amount of the coating solution supplied to the coater head immediately before the supply can be considered. Eventually, various types of degassing devices, bubble separators, etc. can be combined depending on the degree of defoaming required for the coating solution.

1 is an overall schematic diagram illustrating an entire coating apparatus according to an embodiment of the present invention. It is an expanded vertical sectional view of the deaeration apparatus in the coating device. (a) is a sectional view taken along line XX of FIG. 2, and (b) is an enlarged sectional view of a state in which a continuous liquid film collides with the inner wall surface of the vacuum vessel. (a) is sectional drawing similar to FIG. 2 which shows other embodiment of a deaeration apparatus, (b) is the YY sectional view taken on the line of (a). It is sectional drawing which shows other embodiment of a deaeration apparatus. It is a longitudinal section showing a continuous vacuum deaerator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coating liquid tank 2 Coater head S Sheet-like material 3 Coarse foam separator 4 Deaeration device 5 1st cushion tank 6 2nd cushion tank 11 Vacuum vessel 11o Vacuum vessel inner wall surface 12 Coating solution 13 Liquid film 14 Liquid film formation nozzle

Claims (7)

  In a coating apparatus that applies a coating liquid to a sheet-like material, a vacuum container and a liquid film that is disposed in the vacuum container and injects and collides the coating liquid against the inner wall surface of the vacuum container so as to form a continuous liquid film A coating apparatus comprising a deaeration device including a forming nozzle.   The coating apparatus according to claim 1, wherein the liquid film forming nozzle is configured to collide a continuous liquid film substantially perpendicularly to the inner wall surface of the vacuum vessel.   3. The coating apparatus according to claim 1, wherein the continuous liquid film sprayed from the liquid film forming nozzle has a fan shape or a circular shape.   The coating apparatus according to claim 1, wherein the film thickness of the continuous liquid film sprayed from the liquid film forming nozzle is 100 to 500 μm.   The coating apparatus according to any one of claims 1 to 4, wherein a plurality of liquid film forming nozzles are arranged opposite to the inner wall surface of the vacuum vessel and spaced apart from each other in the vertical direction.   The coating apparatus according to any one of claims 1 to 4, wherein a plurality of liquid film forming nozzles are arranged opposite to the inner wall surface of the vacuum vessel and spaced apart in the circumferential direction. At least two cushion tanks are arranged in parallel on the front side of the degassing device, and each cushion tank pressurizes the coating liquid received from the coating liquid receiving port with the pressurized air supplied into the cushion tank, and the coating liquid discharge port By alternately operating the two cushion tanks, the coating liquid is alternately discharged from the coating liquid discharge ports of both cushion tanks, and the liquid film forming nozzle side of the deaeration device The coating apparatus according to claim 1, wherein the pressurized coating liquid is continuously fed to the coating apparatus.

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