JPH06165968A - Application method for coating liquid - Google Patents

Abstract

PURPOSE:To efficiently execute washing of supply pipes and a coater, removal of bubbles and liquid replacement and to decrease the time for changing over a coating liquid and liquid loss by drying at least the slit part of the coater after washing of the coater, then supplying the coating liquid to the coater and applying the coating liquid. CONSTITUTION:The operation in the case of a change over from the state in which from the common supply pipe 20 to the coater 30 are filled with the coating liquid stored in a coating liquid tank 10 to the coating liquid stored in a coating liquid tank 12 is executed by first washing the common supply pipe 20 and the coater 30 with the liquid in a washing liquid tank 27. The washing liquid and bubbles remaining in the supply pipe 20 and the coater 30 are then replaced with deaerated water by the liquid in a deaerated water tank 24. The washing liquid and bubbles are then discharged. Further, the expulsion and drying of the deaerated water in the coater 30 are executed and the liquid in the coating liquid tank 12 is fed by driving a liquid feed pump 21 by which the deaerated water in the line is replaced with the liquid in the coating liquid tank 12. Since the inside of the coater is dried, the generation of the bubbles in the coater does not arise even if the coating liquid is directly supplied thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating liquid coating method used in a coating apparatus for continuously supplying coating liquids of different kinds prepared in at least one coating liquid tank to a coater for coating.

[0002]

2. Description of the Related Art Conventionally, different kinds of coating liquids prepared in at least one coating liquid tank are supplied to a coater using a common supply pipe while switching the flow paths to apply the coating liquids. Things are being done.

In the above system, since a common supply pipe and coater are used, when switching the coating liquid,
It is necessary to clean the common supply pipe and coater. Also, if the coating liquid is switched between the supply pipe and the coater after water sealing, bubbles may be generated in the new coating liquid in the common supply pipe due to residual bubbles during water sealing. It is not preferable to supply the coating solution to the coating solution and to coat the coating solution due to the bubbles, and it is attempted to completely remove the bubbles during water sealing.

Regarding the removal of bubbles during water sealing, for example, as described in Japanese Patent Application Laid-Open No. 49-65824, water that has been degassed in advance is used as a cleaning liquid for a fixed time and a common coating liquid flow path after the common supply pipe and A method of removing the gas remaining in the coating liquid flow path by supplying it to a coater, or a method of cleaning with previously degassed warm water and a low surface tension aqueous solution as described in JP-A-3-207439. It has been known.

Regarding the problem of bubble generation during liquid feeding, for example, as described in JP-A-2-265639, the valve of the pipe connected to the tank of the coating liquid whose supply is to be stopped is closed, and Close the valve behind the common supply pipe part and close the common supply pipe part, switch the valve and connect the vacuum pump to the common supply pipe to perform suction. After evacuating, the valve of the pipe continuous to the tank of the coating liquid to be newly supplied is operated to prevent bubbles from being generated in the common supply pipe.

Furthermore, Japanese Patent Publication No. 62-43722 discloses that
A method of degassing by heating and decompressing is described.

[0007]

Although the conventional method described above makes it possible to prevent cleaning of the common supply pipe and prevent bubbles from remaining, the problem still exists in the coater part. That is, conventionally, deaerated water for bubble removal is supplied even into the coater, but when the deaerated water is replaced with a new coating liquid in the next step, the replacement efficiency is not good, If unevenness occurs and residual bubbles occur during water sealing, the bubbles will remain in the coater. For this reason, a thin film piece is inserted into the slit of the coater and squeezed in the depth direction and the width direction to uniformly displace and remove residual bubbles in the coater. This work is a manual work and must be performed for each slit having 7 to 16 layers, resulting in a large loss time and significantly reducing the production efficiency. Furthermore, the conventional method has a large constant liquid loss, which is disadvantageous in reducing the production cost.

As described above, in the conventional method, a time loss and a liquid loss are constantly generated when the line (common supply pipe) and the coater are sealed with water and then replaced with a new coating liquid. If the substitution loss can be eliminated, the time required for switching the coating liquid and the liquid loss can be greatly shortened, and the production efficiency can be remarkably improved.

[0009]

As is apparent from the above, the object of the present invention is applied to an apparatus for coating different kinds of coating liquid prepared in at least one coating liquid tank by a coater using a common supply pipe. This is a technology that enables efficient cleaning of common supply pipes and coaters, removal of bubbles, replacement, and liquid replacement to significantly shorten the switching time of the coating liquid and to greatly reduce liquid loss. It is to clarify the improved coating method of the coating liquid.

[0010]

A method for applying a coating solution of the present invention which achieves the above object is to wash a coater having at least a liquid reservoir and a slit and then dry at least the slit to form a coating solution. It is characterized in that it is supplied to the coater and applied.

In a preferred embodiment of the coating liquid application method according to the present invention, the supply pipe or path switching valve used for applying the coating liquid is filled with a different coating liquid after cleaning, and the supply pipe is commonly used. Alternatively, a path switching valve is used for coating the different coating liquid, the supply pipe or the path switching valve is filled with the coating liquid after cleaning, and the plurality of coaters are switchably connected. The coating liquid prepared in at least one coating liquid tank is supplied by using a supply pipe having a common path switching valve and a common liquid feed pump. The degassed water inside the coater is supplied by sequentially supplying steam to the coater by the liquid feed pump and switching the path switching valve to the discharge side. Is done by emissions,
The inside of the supply pipe, the liquid feed pump, and the path switching valve is replaced with the different type coating liquid from the degassed water, and after the replacement is completed, the path switching valve is switched to the supply side to supply the different type coating solution to the coating solution. That the coater, the supply pipe, the liquid feed pump, and the path switching valve are independently cleaned, and after the cleaning, the valve of the coating liquid tank is closed and the inside of the coating liquid tank, the supply pipe, and the coater are closed. And reducing the pressure, and opening the valve of the coating liquid tank under reduced pressure to supply the coating liquid. The coater includes a path switching valve and a flow control valve for the coating liquid prepared in at least one coating liquid tank. It is supplied by using a common supply pipe which has a sequence from the side and a means for pressurizing the coating liquid tank,
After the coating is finished, the cleaning is performed by sequentially supplying the cleaning liquid and deaerated water to the coater, and discharging the deaerated water inside the coater by switching the path switching valve to the discharge side. The inside of the pipe, the flow control valve, and the path switching valve is replaced with the heterogeneous coating liquid from the degassed water, and after the replacement is completed, the path switching valve is switched to the supply side to supply the heterogeneous coating solution to the coater. The path switching valve interlocks with the detection signal of the concentration or conductivity of the supplied coating liquid to flow out the coating liquid from the slit portion and apply the coating liquid. There are a plurality of slit portions, and the coating liquid starts coating. At this time, the coating liquid flows out simultaneously from the outlets of the plurality of slit portions or sequentially from the outlets of the lowest layer slit portion with a time lag.

[0012]

In the present invention, conventionally, when the coating liquid was fed into the coater after washing, bubbles were generated due to the residual liquid in the coater. Therefore, the inside of the coater was sealed with water. By drying the slit part of the coater, it becomes possible to directly feed and apply the coating liquid into the coater, and it is possible to remove bubbles with water and replace water (degassed water) with the coating liquid as in the past. It becomes unnecessary. That is, if the inside of the coater is dried after completion of washing, bubbles will not be generated inside the coater even if the coating solution is directly supplied to the coater, and therefore high-quality coating can be performed without trouble due to bubbles. This makes it possible to shorten the time for removing bubbles in the coater and the time for replacing the water (deaerated water) with the coating liquid, and the inside of the coater does not replace the water (deaerated water) with the coating liquid. Therefore, the loss amount of the coating liquid can be greatly reduced.

[0013]

DETAILED DESCRIPTION OF THE INVENTION The method of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is an example of a schematic view of an apparatus to which the method of the present invention is applied, in which each coating solution contains a plurality of coating solution tanks 10.
The coating liquid of the specific coating liquid tank 10 is introduced into the common supply pipe 20 by opening the valve 11 prepared for each coating liquid tank.
Is supplied to the coater 30 through the filter 22 and the path switching valve 23. In addition, 24 is a deaerated water tank and 25 is a defoaming device.

Next, how the coating liquid coating method according to the present invention is carried out according to the above-mentioned apparatus will be described.

First, from the common supply pipe 20 to the coater 30.
The operation of switching from the state in which the above is filled with the coating liquid stored in the coating liquid tank 10 to the coating liquid stored in the coating liquid tank 12 will be described.

The common supply pipe 20 has at least 2
The present invention refers to a supply pipe used for feeding a seed coating liquid. However, the present invention provides a plurality of series supply pipe systems of two or more series, regardless of the common supply pipe 20, to provide one coater. However, it also includes a mode in which they are used properly.

First, with the valve 11 of the coating liquid tank 10 closed and the path switching valve 23 fixed to the coater 30 side, the valve 29 of the cleaning liquid tank 27 is closed.
To open the feed pump 21 to drive the common supply pipe 20.
And after cleaning the coater 30, the valve 29 is closed,
Next, the valve 26 of the degassed water tank 24 is opened, and the cleaning liquid and bubbles remaining in the common supply pipe 20 and the coater 30 are replaced with degassed water to discharge the cleaning liquid and bubbles. Discharge to the waste liquid tank.

Next, the path switching valve 23 is switched to the discharge side, the deaerated water in the coater is discharged, and the line up to the path switching valve 23 is sealed with the deaerated water.

In parallel with the above operation, deaerated water in the coater 30 is removed and dried. In order to remove the deaerated water in the coater 30, the valve of the line leading from the lower side of the coater 30 to the waste liquid tank is opened and allowed to fall naturally, or the blower pipe connected to the lower line of the coater 30. (Heated) air is sent through and the deaerated water is discharged at that pressure.

The coater slit 4 may be dried by sending heated air or unheated air through a blower pipe connected to the lower line of the coater 30 to discharge the degassed water, or the slit outlet. Heated air or non-heated air may be blown from No. 5. Further, paper or non-woven fabric having good water absorption may be inserted into the slit to remove water. In a mode in which a plurality of coaters 30 are connected to the common supply pipe 20, a new coater 3
When the coating is performed at 0, the washed coater 30 may be naturally dried without blowing air. Instead of air, another gas may be used, or the coater may be dried by heating.

Next, with the valve 26 of the degassed water tank 24 closed and the valve 13 of the next coating liquid tank 12 open, the liquid feed pump 21 is driven to switch the degassed water in the line. The line up to the path switching valve 23 is replaced with the coating liquid by an operation of discharging it to a waste liquid tank (not shown) through 23. The flow rate at the time of replacement with the coating liquid is an important factor for minimizing the replacement loss, and is generally 9 cm / sec or less, preferably 6 cm / se.
c or less, and more preferably 3 cm / sec or less.

The replacement of the degassed water with the coating solution is performed, for example, by changing the concentration,
When the replacement completion detection sensor that detects turbidity or conductivity is detected, the path switching valve 2 is interlocked with the signal.
3 is switched to the coater 30 side, the coating liquid is discharged simultaneously from a plurality of slit portion outlets or sequentially from the slit portion outlet of the lowermost layer, and when the slide surface is prepared, the coating operation can be restarted.

The liquid flow velocity in the gas-liquid exchange of the coater 30 must be set within the range where the interface of the liquid head portion at the liquid reservoir inlet 6 is not disturbed. As an example, a liquid having a surface tension of 40 dyne / cm was used for the washed coater, the coating liquid viscosity was set to 4 types, the liquid supply flow rate was set to 4 types, and the slit was in a dried state and a wet state (undried state). In this case, the generation state of bubbles was visually inspected. The results are shown in Table 1 below. In Table 1, ◯ indicates that no bubbles were generated, and x indicates that even one bubble was generated.

[0025]

[Table 1]

It can be seen from Table 1 that the liquid can be supplied without generating bubbles by setting the viscosity to 8 CP or more and the flow rate to 15 cm / sec or less. In addition, the same experiment as above was conducted except that the surface tension of the liquid was changed.
It was found that it is possible to supply the liquid without bubbles even in the range of 5 to 75 dyne / cm.

In the liquid feeding method described above, following the replacement with degassed water in the line, the degassed water is discharged and the line is depressurized, and the coating liquid may be introduced in this state. . That is, when sending the coating liquid, the valve 13 of the coating liquid tank 12 and the valve 2 of the degassed water tank 24
6 and the valve 29 of the cleaning liquid tank 27 are closed, the pressure of the coating liquid tank 12, the common supply pipe 20 and the coater 30 is reduced, and the valve 13 of the coating liquid tank 12 is opened under reduced pressure to feed the coating liquid. It is a composition. A vacuum pump is used to reduce the pressure in the line, but by reducing the pressure, replacement with the coating liquid can be performed quickly, and at that time,
Bubbles are prevented from being generated in the coating liquid in the line.

The coating method of the present invention includes a mode in which the coating solution and degassed water are delivered to the coater 30 without using the delivery pump 21. That is, in the coating liquid coating method in which different types of coating liquids prepared in at least one coating liquid tank 12 are supplied to the coater 30 by using a common supply pipe, coating is performed in the coating liquid tank 12 and degassing. Means for pressurizing the water tank 24 and the cleaning liquid tank 27,
A common supply pipe 20 and a flow rate control valve and a path switching valve 23 arranged in the common supply pipe 20 in the preceding stage of the coater 30 are prepared, and the valve 11 of the coating liquid tank 10 is prepared.
Is closed, the valve 29 of the cleaning tank 27 is opened, and the cleaning liquid in the cleaning liquid tank 27 under pressure is supplied to the common supply pipe 20, so that the coating liquid remaining in the common supply pipe 20 and the coater 30 After discharging the
Is closed, and then the valve 26 of the degassed water tank 24 is opened to discharge the cleaning liquid, and then the path switching valve 23 is switched to the discharge side to seal the inside of the common supply pipe 20 with degassed water and to coat the coater. The degassed water in 30 is discharged, dry air is supplied to dry the inside of the coater 30, and the valve 26 of the degassed water tank 24 is closed to prepare a coating liquid to be newly coated. The valve 13 of the coating liquid tank 12 is opened and the pressurized coating liquid of the coating liquid tank 12 is supplied to the common supply pipe 20 so that the common supply pipe 2
The deaerated water in 0 is discharged and replaced with a new coating liquid, and after the replacement is completed, the path switching valve 23 is switched to the dried coater 30 side to supply the new coating liquid to the coater 30. This is a liquid application method.

In this method, the liquid feed pump 21 is not used, and the coating liquid tank 12 and the cleaning liquid tank 2 are hermetically sealed.
7 and the degassed water tank 24, the liquid can be sent only by pressurizing the compressed air. According to this method, there is an advantage that it is not necessary to consider the generation of bubbles due to the driving of the liquid feed pump 21.

Further, as shown in FIG. 1, the line from the liquid feed pump 21 to the path switching valve 23 and the coater 30 should be arranged so that the coating liquid or degassed water flows upward from bottom to top. Is preferred. Contrary to this method, if piping is used so that the coating liquid or degassed water is supplied downward, the specific gravity of the coating liquid is heavier when the inside of the pipe is replaced with the coating liquid. Therefore, at the boundary between both liquids, the coating liquid enters into the degassed water region in a wedge shape, and the portion where both liquids are mixed must be discharged, resulting in a significant loss of the coating liquid. I will let you.

In the above-mentioned coating method, the mixed deaeration cleaning water is supplied without separating the deaeration water and the cleaning liquid to clean the common supply pipe 20 and the coater 30, and the deaeration water and the cleaning liquid. It also includes a mode in which the supply order of is reversed and a mode in which degassed water and a cleaning liquid are supplied simultaneously.

Further, in the embodiment shown in FIG. 1, the coater 30
Although the path switching valve 23 is arranged immediately before, the mode may be arranged such that the path switching valve 23 is arranged before the defoaming device 25. In such an embodiment, the defoaming device 2
The cleaning (drying) of 5 may be performed in the same series as the step of cleaning (drying) the coater 30, or may be performed in a separate series independent of the coater 30.

Furthermore, a plurality of coaters 30 are prepared, the line is switched to the washed and dried coater side by the path switching valve 23, and a new coating liquid replaced from degassed water is supplied, An embodiment in which the coater 30 is washed and dried in separate steps is also included in the method of the present invention. Furthermore, in this embodiment, the cleaning of the coater 30 is performed at the same time as the common supply pipe 20 and only the discharge and drying of the cleaning water are performed in separate steps.

When the line sealed with deaerated water is replaced with the coating liquid, it is not preferable that the coating liquid is discharged as waste liquid outside the line, which is so-called liquid loss.
Such liquid loss is caused by the difference in specific gravity and viscosity between the two liquids when the degassed water moves in the pipe while being pushed out by the coating liquid, and there is also the problem of frictional resistance with the inner wall of the liquid. It is caused by the wedge-shaped intersections of the contact portions. That is, at the intersection of the two liquids, the central cross-sectional shape will be described. It was found that the coating liquid has a wedge-like shape protruding into degassed water, and the length of the wedge-shaped portion is related to the flow velocity.

The pipe length is 400 mm and the viscosity of the coating liquid is 40 c.
When a comparative experiment was performed with a tube diameter of 15 mm and a tube diameter of 10 mm set to ps, it was found that there was a difference in liquid loss shown in FIG. As is clear from the figure, at the same flow rate, the larger the pipe diameter, the greater the liquid loss.
If the pipe diameter is the same, the higher the flow velocity, the greater the liquid loss.

[0036]

According to the method of the present invention, the slit portion of the coater is washed and then dried, and the coating liquid is supplied to the coater to apply the coating liquid. The coating liquid can be exchanged without performing the removing work, the work efficiency can be remarkably improved, and the above-mentioned problems can be solved.

[Brief description of drawings]

1 is a schematic diagram of an apparatus for carrying out the method of the present invention.

FIG. 2 is an enlarged sectional view of a coater for carrying out the method of the present invention.

FIG. 3 is a graph showing liquid loss.

[Explanation of symbols]

 1 Base 2 Back Roll 3 Decompression Chamber 4 Slit 5 Slit Exit 6 Liquid Reservoir Inlet 7 Liquid Reservoir 10 Coating Liquid Tank 11 Valve 20 Common Supply Pipe 21 Liquid Transfer Pump 22 Filter 23 Route Switching Valve 24 Degassing Water Tank 25 Defoaming device 26 Valve 30 Coater 12 Coating liquid tank 13 Valve 27 Cleaning liquid tank 29 Valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shukei Ueno 1 Sakura-cho, Hino-shi, Tokyo Konica Co., Ltd. (72) Inventor Nobuhiko Takashima 1 Sakura-cho, Hino-shi, Tokyo Konica, Co. Ltd. (72) Inventor Takayuki Kato 1 Sakura-cho, Hino-shi, Tokyo Konica Stock Company

Claims (9)

[Claims] 1. A method for applying a coating liquid, which comprises: washing a coater having at least a liquid reservoir and a slit; then drying at least the slit; and supplying the coating liquid to the coater for coating. 2. A supply pipe or a path switching valve used for coating the coating liquid is filled with a different coating liquid after cleaning,
The coating solution coating method according to claim 1, wherein the supply pipe or the path switching valve is commonly used for coating the different coating solution. 3. The supply pipe or the path switching valve is filled with the coating liquid after cleaning, and is switchably connected to a plurality of the coaters.
The coating method of the coating liquid according to. 4. The coater supplies the coating liquid prepared in at least one coating liquid tank by using a supply pipe having a common path switching valve and a common liquid feed pump. After the completion of cleaning, the cleaning liquid and deaerated water are sequentially supplied to the coater by the liquid feeding pump,
This is performed by discharging the degassed water inside the coater by switching the path switching valve to the discharge side, and the inside of the supply pipe, the liquid feed pump, and the path switching valve is replaced with the different coating liquid from the degassed water. And after the replacement,
The coating liquid coating method according to claim 1, wherein the path switching valve is switched to a supply side to supply the different coating liquid to the coating liquid. 5. The method for applying a coating liquid according to claim 2, wherein the coater, the supply pipe, the liquid feed pump, and the path switching valve are independently cleaned. 6. After the cleaning, the valve of the coating liquid tank is closed, the pressure inside each of the coating liquid tank, the supply pipe and the coater is reduced, and the valve of the coating liquid tank is opened under reduced pressure to supply the coating liquid. The coating method of the coating liquid according to claim 4 or 5, wherein 7. The coater comprises means for pressurizing the coating solution prepared in at least one coating solution tank to a common supply pipe having a path switching valve and a flow rate control valve in order from the coater side and the coating solution tank. After the application, the cleaning liquid and degassed water are sequentially supplied to the coater, and the degassing inside the coater is performed by switching the path switching valve to the discharge side. It is performed by discharging water, and the inside of the supply pipe, the flow rate control valve, and the path switching valve is replaced with the different type of coating liquid from the degassed water. The coating liquid coating method according to claim 1, wherein the coating liquid is supplied to the coater. 8. The path switching valve interlocks with a detection signal of the concentration or conductivity of the supplied coating liquid to flow out the coating liquid from the slit portion and apply the coating liquid. 7. The method for applying the coating liquid according to 7. 9. The coating liquid is provided with a plurality of slits, and the coating liquid flows out from the outlets of the slits at the same time or sequentially from the outlets of the slits of the lowermost layer with a time lag at the start of coating. Claims 2 to 8
The coating method of the coating liquid according to.