JP4590877B2 - Coating equipment - Google Patents

Description

The present invention relates to a coating apparatus, and more particularly to a coating apparatus capable of cleaning the inside of a die coater pipe that performs coating with a die head.

Conventionally, when coating is performed using a coating apparatus, various systems such as gravure coating, roll coating, slide coating, curtain coating, and extrusion coating are used depending on the application. In particular, when high-quality and stable coating is performed at high speed, an extrusion coat, a curtain coat, a slide coat or the like is employed, and a die head having a slit nozzle is used.

FIG. 4 is a cross-sectional view showing an outline of the internal structure of the die head having the slit nozzle. Die heads that are used for high-quality coating have a narrow slit opening thickness (gap) a in order to make the coating amount uniform in the width direction, and the manifold 28 has a relatively large volume. It is common to do.

However, because of the structure having a minute opening and a large volume liquid storage part immediately before, such a die head has a poor internal liquid replacement property and it is difficult to flow a large amount of liquid at a time. There is a problem that the cleaning performance is extremely poor when cleaning is required, such as when switching between the two.

Therefore, in the actual cleaning situation, a large amount of solvent or the like is passed over a long period of time, or the die head is disassembled and cleaned for a more reliable effect. Both the work load and the work load.

In order to solve the above problem, a coating head cleaning method (for example, see Patent Document 1) having a slit nozzle has been devised to efficiently clean the inside of the die head in a short time.

Further, the slit nozzle cleaning method and cleaning mechanism (see, for example, Patent Document 2) can completely remove the solidifying coating liquid remaining at the tip of the slit nozzle of the die head without causing a reduction in work efficiency. .) Is also known.

On the other hand, in the piping portion connected to the die head for supplying the coating liquid to the die head, as shown in FIG. 1, the coating liquid is uniformly and stably discharged from the tip of the slit nozzle of the die head. Generally, a coating liquid filter 23, a coating liquid supply pump (constant flow pump) 20, and the like are attached.

Accordingly, the piping portion also has a portion having a complicated shape on the inner surface or a large volume liquid storage structure, and the cleaning performance is extremely poor. Also in the situation where actual cleaning is performed, a large amount of solvent is passed over a long period of time, or in order to achieve a more reliable effect, the pump is disassembled and cleaned. Replacing it with a new one has been taken, and it has become an excessive load like the cleaning inside the die head.

In order to solve the above problems, a die coater paint cleaning device (for example, patent document) that uses a compressed gas or a pig to reduce paint loss at the time of cleaning and can be efficiently cleaned in a short time using a small amount of a cleaning solvent. 3) is known.

The patent literature is as follows.
JP-A-7-132267 JP 2003-10767 A JP-A-9-85153

In contrast to such poor cleaning performance of the die coater type coating apparatus, Patent Document 1 introduces a solvent into the inside of the die head and blows an inert gas from the vicinity of the die head connecting portion of the pipe to “bubbles”. It is trying to efficiently wash the inner wall of the die head manifold and the slit nozzle.

However, this method is sufficient for a die head having a slit gap of about 0.1 mm used in a field in which a smaller amount of coating liquid is required to be precisely applied, for example, in the manufacture of a color filter for a liquid crystal display device. The effect cannot be obtained. Further, this method cannot be applied to the piping portion.

This is because according to the example of Patent Document 1, 1.0 l / min of nitrogen is blown into the die head having a slit gap of 0.5 mm while a cleaning solution of 3.0 l / min is being flown, and this level of flow is actually secured. Otherwise, the “bubble flow”, which is a turbulent flow in which bubbles are dispersed in the liquid, does not occur. However, in the die head having a slit gap of about 0.1 mm, which is usually used at a discharge rate of about 30 to 300 ml / min, This is because it is extremely difficult to obtain a large flow rate, and as a result, the cleaning liquid is separated into two layers of gas and liquid and the desired cleaning state cannot be maintained.

Also, in the piping portion, the bubble flow loses the dispersed state and separates into two layers while passing through the narrow and long pipe, so that the desired cleaning state cannot be maintained.

Patent Document 2 discloses a method and mechanism for performing cleaning by injecting cleaning liquid from a nozzle placed at an elevation angle and air from a nozzle placed at a depression angle with respect to a slit nozzle tip of a die head. . However, this is intended for the outside of the nozzle, and no cleaning of the inner surface is assumed.

Patent Document 3 discloses a device that facilitates subsequent cleaning by directly introducing compressed gas into a pipe, or removing a paint remaining in the pipe by moving the compressed gas after inserting a pig. Are listed.

Furthermore, in this document, by supplying a mixed gas cleaning agent that is a mixture of compressed gas and cleaning solvent to the pipe after extrusion, the cleaning effect is not reduced as compared with the case where only the cleaning solvent is pumped. An apparatus that enables pipe cleaning with a small amount of cleaning solvent is also described.

However, even with any of these devices, it cannot be applied to all of the piping parts and die heads to which the coating liquid supply pump or the like is connected, or even if applied, sufficient effects cannot be obtained. .

This is because when compressed gas is introduced directly into the pipe, the paint (coating liquid) remaining in the pipe may dry out and become foreign matter even after the gas is introduced. This is because there is a risk of damaging the resin piping often used in the field where mixing with the coating film is disliked.

In the field where it is required to apply a smaller amount of coating liquid precisely, the generation of dry foreign matter in the coating liquid means that the coating film is defective, and it is more difficult to drop the coating liquid if the piping is damaged. It can also be a cause. Furthermore, the pig has a problem that it is clogged at a narrow part such as a slit nozzle or a part having a complicated inner surface shape such as a pump.

On the other hand, even when supplying the gas-mixed cleaning agent, cleaning of the pump and the die head is incomplete unless a mechanism for controlling the mixing of gas and solvent is provided in the apparatus. In fact, Patent Document 3 describes that a pump joint should be connected so that the pump can be easily separated and disassembled.

The present invention has been made to solve the conventional problems in the cleaning of the above-described coating apparatus, and is a die coater having a complicated piping path, and in particular, precisely coats a smaller amount of coating liquid. Therefore, there is provided a method and apparatus for satisfactorily cleaning the inside in a short time without being decomposed.

Such present invention in claim 1, and die head, and a coating liquid supply pump, and the coating liquid reservoir, the coating apparatus comprising a coating liquid piping connecting them, in the middle before Kinuriko liquid pipe Gas mixed solvent delivery means is connected, and the gas mixed solvent delivery means is connected to a solvent container, a solvent pipe connected to the solvent container, a gas storage container for mixing, and a gas storage container for mixing. A mixing gas pipe, a mixing valve for connecting the terminal end of the solvent pipe and the terminal end of the mixing gas pipe, and a gas mixed solvent delivery pipe extending from the mixing valve. It has a function of adjusting the flow rate and mixing ratio of the gas for mixing, the solvent container is equipped with a solvent usage measuring mechanism, the gas storage container is equipped with a gas usage measuring mechanism, and the solvent and mixing gas usage According to the above for mixing By providing a coating apparatus characterized by having means for controlling the opening and closing of the gas, the gas mixed solvent in which the gas and the solvent are mixed is sent out from the middle of the coating pipe while maintaining an arbitrary gas-liquid ratio. Then, the coating apparatus which can perform the washing | cleaning which can clean a die-coater piping and the inside of a die head with a high effect is provided. In addition, by finely controlling the introduction / non-introduction of the solvent mixture or gas, or a mixture thereof, which is a mixture thereof, according to the amount of solvent / gas used, the liquid replacement property in the die coater is poor and washing is difficult. By replacing the coating liquid with gas without drying, and then using the gas-liquid distribution equilibrium generated by passing the gas-liquid interface by raising and lowering the internal liquid level, The present invention provides a coating apparatus that can be cleaned with an effect . Also provided is a coating device capable of cleaning the die coater pipe and the inside of the die head with a high effect by sending out the gas mixed solvent mixed by the mixing valve while maintaining an arbitrary gas-liquid ratio. It is.

According to a second aspect of the present invention, in the coating apparatus according to the first aspect, the gas mixed solvent delivery means has a mechanism capable of connecting an end of the coating liquid pipe removed from the coating liquid storage container. A coating apparatus capable of performing cleaning similar to that of claim 1 by providing a coating apparatus characterized by being connected to a pipe, and connecting the end of the coating pipe to a gas mixed solvent creating means. Is to provide.

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Application according to claim 3 invention is to provide a coating apparatus according to claim 1 or 2, characterized in that it has a flow rate control means of the solvent. Thus, the present invention provides a coating apparatus that can perform dynamic flow rate control of a cleaning solvent in order to keep a gas and a solvent in an appropriate mixed state.

The present invention according to claim 4 provides the coating apparatus according to any one of claims 1 to 3 , further comprising a mixing gas flow rate control means. Thus, the present invention provides a coating apparatus capable of performing dynamic flow rate control of a mixing gas in order to keep the gas and the solvent in an appropriate mixed state.

According to the present invention, a die coater having a complicated piping route, particularly for those requiring a precise coating of a smaller amount of coating liquid, it is possible to clean the inside well in a short time without being decomposed. It became possible to provide a possible coating device.

The coating apparatus of the present invention is configured to increase the inside of the pipe by sending out a gas mixed solvent in which gas and liquid are mixed from the middle of the pipe connected to the die head through an accessory device such as a pump from the coating liquid storage container. FIG. 1, which is a reference example, has a function of cleaning by effect, and shows an example of a die coater in which piping for introducing a gas mixed solvent is connected via a valve. Here, the flow from the introduction valve 12 on the die head side is sent in the same direction as at the time of coating, and the flow at the coating liquid supply side is sent out in the direction opposite to that at the time of coating. While the coating liquid supply side is being washed, the coating liquid storage container is replaced with a waste liquid collection container.

In addition to such a waste liquid recovery mechanism, the present invention may include other mechanisms. For example, a transport mechanism or a coating thickness adjustment mechanism.

Moreover, the introduction part of the said gas mixed solvent may be not the middle of coating liquid piping but an edge part. In this case, a connecting mechanism is prepared in the pipe for introducing the gas mixed solvent, and at the time of cleaning, the coating liquid pipe is removed from the coating liquid storage container and connected to the connecting mechanism. FIG. 2, which is a second reference example, shows a die coater in which a pipe for introducing a gas mixed solvent is connected via a coupling mechanism when the gas mixed solvent is introduced from the end of the coating liquid pipe. An example is shown.

In this apparatus, the gas mixed solvent is introduced from the middle or the end of the coating liquid piping as described above. At that time, the target cleaning can exert the most effect on the gas-liquid mixing ratio and the delivery flow rate of the gas mixed solvent. It is important to maintain the value. If this is not done, it is not possible to expect an improvement in the degree of cleaning compared to a method in which only the solvent is flowed, although the amount of solvent used can be reduced somewhat.

The optimum gas-liquid mixing ratio varies depending on the pipe length, pipe diameter, equipment / equipment installed along the way, the viscosity of the coating liquid and the cleaning solvent used, etc. The solvent is about 1: 2 to 3: 1.

Similarly, the optimum flow rate varies depending on various conditions, but is approximately 1 to 3 times the discharge amount during coating, and approximately 30 ml / min to 900 ml / min when using the die head with the slit gap of about 0.1 mm. .

It should be emphasized here that this gas mixed solvent is not in a system in which minute bubbles are dispersed in the solvent. Even if the mixed solvent in such a state is blown into the pipe, it is separated into two layers while passing through the long pipe, and even if a gas-liquid dispersed solvent is flowed through the pipe, the cleaning performance is not greatly improved.

The “gas mixed solvent” in the present invention refers to an aspect in which the gas and the solvent are regularly sent out in a short cycle, and the situation where the gas and the solvent pass through the pipe every about 3 ml to 20 ml, respectively. Become. Thus, the coating liquid is eluted from the wall surface into the liquid phase to be cleaned using the gas-liquid distribution equilibrium generated when the interface between the gas and the solvent passes through the inner wall of the pipe.

As the gas mixed solvent delivery means in an actual apparatus, a mechanism that maintains the gas-liquid mixing ratio and the delivery flow rate at optimum values may be provided so that the gas and the solvent are delivered in a short cycle. For example, it may be possible to keep the gas and solvent delivery pressures at a certain ratio, or restrict the gas / solvent flow path cross-sectional area to limit the respective delivery amounts, but the invention is not limited to these. .

However, the optimum gas and solvent delivery rate and mixing ratio vary depending on the configuration of the coating piping to be cleaned, the coating liquid remaining at the time of cleaning, and the viscosity of the cleaning solvent used. It is convenient that can be set arbitrarily.

Corresponding to the above situation, a configuration having a function of adjusting the flow rate and mixing ratio of the solvent and the mixing gas is also possible. FIG. 3 is a schematic diagram showing the configuration of the present apparatus in this case. In this apparatus, the opening of the delivery flow rate adjusting mechanism 7 of the solvent container 4 and the mixing gas flow rate adjusting valve 17 of the mixing gas piping 15 in consideration of the configuration of the coating piping, the viscosity of the coating solution and the cleaning solvent, and the like. In the mixing valve 10, the gas and the solvent are mixed at an arbitrary ratio according to the setting, and sent from the introduction valve 12 into the die coater pipe.

As the gas mixed solvent adjusting mechanism for adjusting the flow rate and the mixing ratio of the solvent and the mixing gas in this way, a configuration in which the flow rates of the mixing gas and the solvent are adjusted and not controlled in the gas mixed solvent state is simple and preferable. Not limited to the above, adjusting the flow rate of the mixing gas without adjusting the solvent, adjusting the flow rate to the whole mixed gas solvent, determining the mixing ratio and adjusting the flow rate of the specified mixed solvent, adjusting at all stages Etc. are also possible.

The flow rate is generally adjusted by a valve, but may be adjusted by various means such as a metering pump. Furthermore, as the piping, it is possible to use various mixing devices that form part of a gas mixed solvent adjusting mechanism such as a valve, as well as simple tridents.

The above method can efficiently clean the inside of the die coater's piping, but in parts that have poor liquid replacement properties such as coating liquid supply pumps and die heads and are difficult to clean, the degree of cleaning is higher compared to conventional methods. Although the coating solution still remains in a small amount.

The introduction or non-introduction of the above gas mixed solvent, which is a gas or a solvent, or a mixture thereof, is finely controlled in accordance with the solvent weight used and the volume of the gas mixed with respect to a site that is difficult to clean due to such poor liquid substitution. Further, a configuration in which the part is washed with a high effect is also possible. In this case, the present apparatus uses a weight change indicated by the load cell 13 provided in the solvent container 4 and an integrated value of the flow meter 18 provided in the mixing gas pipe 15 to determine a site that is difficult to clean in advance. Depending on the internal volume, the coating liquid is replaced with a gas, the solvent is filled, and the solvent is discharged to achieve cleaning using gas-liquid distribution equilibrium by passing through the gas-liquid interface.

The transition of cleaning in this method will be described below by taking the case where it is applied to the die head shown in FIGS. 4 and 5 as an example.

At the end of coating, the die head manifold 28 is filled with the coating liquid. Therefore, first, the coating liquid is replaced by feeding a gas mixed solvent from the coating liquid supply port 30.

At this time, the solvent component of the gas mixed solvent is discharged from the slit nozzle 29 together with the coating liquid, and the gas accumulates from the upper portion, so that the liquid is finally retained without fear of drying. Can be filled with gas.

Next, when the coating liquid is completely discharged, only the solvent is fed into the manifold 28 and filled with the solvent. Here, if the air vent port (air vent port) 31 exists in the die head, the solvent can be more efficiently filled by opening the air vent port 31. The point in time when the coating liquid is completely discharged is determined by comparing the volume of the manifold 28 with the amount of solvent used obtained by the load cell 13 provided in the apparatus and the amount of gas used for mixing integrated by the gas flow meter 18 for mixing. can do.

Finally, when the manifold 28 is filled with the solvent, the gas mixed solvent is fed again and the solvent is discharged. At this time, the gas is collected from the upper part, and the coating liquid is eluted from the wall surface into the liquid phase to be cleaned using the gas-liquid distribution equilibrium generated when the gas-liquid interface passes.

If the effect is insufficient with one cleaning operation as described above, more complete cleaning can be expected by repeating filling and discharging of the solvent. Further, after the cleaning is completed, the drying can be performed by sending only the gas to prepare for the next coating. Similarly, the point of time when the solvent is filled can be determined from a comparison between the volume of the manifold 28 and the amount of solvent used.

Of course, the above method of measuring the amount of use by changing the weight of the solvent and integrating the flow rate of the gas is simple, but other means may be used.

Further, in addition to the control based on the amount used, control by comparing the elapsed time with the gas mixture solvent or the flow rate of the solvent / gas, for example, in the apparatus of FIG. Further, the operation may be performed by calculating the amount of the gas mixture solvent extruded from the comparison of the opening degree of the mixing gas flow rate adjusting valve 17 and the cleaning elapsed time. If possible, the cleaning operation is controlled by measuring the cleaning degree itself. It doesn't matter.

The solvent used for the above-mentioned cleaning is not particularly limited. However, considering that a metal is usually used as the material of the die head and the ease of drying after cleaning is considered, methanol, ethanol, isopropanol, cyclohexane, acetone, 2- Low boiling point organic compounds such as butanone and dichloromethane are considered suitable.

Similarly, the gas to be used is not particularly limited, but when a flammable substance such as a lower alcohol or a low molecular ketone is employed as the solvent, it is desirable to select an inert gas such as nitrogen or argon.

It is also possible to perform cleaning with two or more solvents used. In this case, a plurality of solvent containers, load cells, solvent flow meters, and the like are prepared, and piping is connected to the mixing valve via the switching valve.

The mechanism that performs the cleaning operation is not limited as long as the gist of the cleaning can be realized, but various monitoring and control by a programmable logic controller (PLC) is less sensitive to the time lag of control. Easy and preferable.

As described above, an important factor in the washing of the die coater pipe according to the present invention is that the gas-liquid mixing ratio and the delivery amount of the gas mixed solvent are maintained at the optimum values. As described above, the mixing gas flow rate adjusting valve 17 is adjusted. However, even when the same die coater is washed, the set values of the solvent delivery flow rate adjusting mechanism 7 and the mixing gas flow rate regulating valve 17 that achieve the gas-liquid mixing ratio and delivery rate are not always constant. Absent.

This is because the set value may vary depending on the type of coating liquid filled before cleaning, and even changes due to a decrease in the remaining coating liquid in the piping due to progress in cleaning. Because there is sex. This is because the viscosity varies depending on the coating liquid, and the resistance of the piping against extrusion changes due to the replacement of the coating liquid with a solvent having a lower viscosity than the normal coating liquid.

In addition, even when the set value for achieving the optimum gas-liquid mixing ratio moves due to the change in the cleaning environment as described above, the apparatus has a function of dynamically controlling the flow rate of the cleaning solvent and maintaining the mixing state. It is also possible to do.

Similarly, even if the set value for achieving the optimal gas-liquid mixing ratio moves due to the change in the cleaning environment as described above, the apparatus has a function of dynamically controlling the flow rate of the mixing gas and maintaining the mixed state. It is also possible to do.

In both of the above devices, the gas-liquid mixing ratio and the gas mixture solvent delivery amount are calculated from the weight change rate indicated by the load cell 13 provided in the solvent container 4 and the measured value of the flow meter 18 provided in the mixing gas pipe 15. In the apparatus according to the invention according to claim 5 of the present invention, the result is fed back (feedback) to the solvent delivery flow rate adjusting mechanism 7, and in the apparatus according to claim 6 to the mixing gas flow rate adjusting valve 17. ) To realize the function.

The present invention relates to a coating apparatus, and more particularly, to a method and apparatus for cleaning the inside of a die coater pipe that performs coating with a die head.

A reference example of a coating apparatus . Reference example 2 of coating equipment . Schematic of the 1st example of the coating device which has the washing | cleaning mechanism of this invention. The front view which shows an example of a die head. The right view which shows the die head of FIG.

DESCRIPTION OF SYMBOLS 1 ... Cleaning machine solvent supply part 2 ... Cleaning machine mixing gas supply part 3 ... Die head 4 ... Solvent container 5 ... Solvent piping 6 ... Solvent on-off valve 7 ... Delivery amount adjustment mechanism 8 ... Solvent flow meter 9 ... Solvent filter 10 ... Mixing valve 11 ... Gas mixed solvent supply pipe 12 ... Introduction valve 13 ... Load cell 14 ... Mixing gas container 15 ... Mixing gas pipe 16 ... Mixing gas on-off valve 17 ... Mixing gas flow rate adjustment valve 18 ... Mixing Gas flow meter 19 ... coating liquid storage container 20 ... coating liquid supply pump 21 ... coating liquid piping 22 ... easy connection joint (one-touch coupler)
23 ... Coating liquid filter 24 ... Coating liquid introduction valve 25 ... Air vent valve (air vent valve)
26 ... Coating liquid receptacle 27 ... Waste liquid tank 28 ... Manifold 29 ... Slit nozzle 30 ... Coating liquid introduction port 31 ... Air vent port (air vent port)

Claims (4)

A die head, a coating liquid feed pump, and the coating liquid reservoir, the coating apparatus comprising a coating liquid piping connecting them, and before Kinuriko liquid pipe midway in the gas mixture solvent delivery means is connected The gas mixed solvent delivery means includes a solvent container, a solvent pipe connected to the solvent container, a gas storage container for mixing, a gas pipe for mixing connected to the gas storage container for mixing, A mixing valve for connecting the terminal end of the solvent pipe and the terminal end of the mixing gas pipe, and a gas mixed solvent delivery pipe extending from the mixing valve; and a flow rate and a mixing ratio of the solvent and the mixing gas. It has a function to adjust, the solvent container is equipped with a solvent usage measuring mechanism, the gas storage container for mixing is equipped with a gas usage measuring mechanism, and the mixing valve is opened and closed according to the amount of solvent and gas used for mixing. Have means to control Coating and wherein the.   2. The coating apparatus according to claim 1, wherein the gas mixed solvent delivery means is connected to a pipe having a mechanism capable of connecting an end of the coating liquid pipe removed from the coating liquid storage container. Coating equipment. Coating apparatus according to claim 1 or 2, characterized in that it has a flow rate control means of the solvent. Coating apparatus according to any one of claims 1-3, characterized in that it comprises a flow rate control means of the mixing gas.

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