JP2002346312A - Filter medium treatment method in liquid feed flow channel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter medium treatment method in a liquid feed flow channel capable of certainly preventing the mixing with air bubbles by short- time treatment work using a simple apparatus. SOLUTION: A liquid feed pipe, a filter medium housing 3 and a defoaming part 8 are evacuated by a vacuum pump 11 and, in this state, the hot water stored in a filter medium treatment liquid tank 6 is allowed to fill the liquid feed pipe and the filter medium housing 3 through a liquid feed pump 2. Whereupon, the hot water enters the filter medium housing 3 up to the interior thereof to enter voids or to form a periphery wetted state and also enters the scratch or the like of the liquid feed pipe to form a periphery wetted state. Next, the filled hot water is discharged from a drain pipe 7 and, thereafter, hot water is again allowed to fill the liquid feed pipe and the housing 3. In this state, the feed of the coating liquid in a liquid storage tank 1 is started.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a filter medium in a liquid sending flow path used in a coating apparatus or the like so that bubbles are not mixed into the liquid sending liquid.

[0002]

2. Description of the Related Art Generally, in the next step, for example, a liquid feeding method for supplying a coating liquid to a coating apparatus using a liquid feeding flow path,
In order to remove impurities and the like, a filter medium is provided in the liquid sending flow path. However, when the coating liquid is sent through such a filter medium, air remaining in the pores of the filter medium is mixed into the coating liquid as air bubbles, and when the coating liquid containing air bubbles is applied to the substrate, it becomes a defect. Met.

Therefore, various techniques have been proposed to prevent bubbles from being mixed into a liquid to be fed such as a coating liquid. For example, in Japanese Patent Publication No. 58-48891, saturated steam generated under a pressure higher than the reduced pressure but lower than the atmospheric pressure is guided into a flow path in a reduced pressure state. A method has been proposed in which degassed liquid is guided to a flow path. JP-B-62-43722 and JP-B-2-49149 disclose a method in which degassed hot water is passed through a flow path, air present in the flow path is extruded, and a liquid to be used is supplied. Has been proposed. Tokuhei 1-
In Japanese Patent No. 17729, in order to eliminate air on one side of a candle filter arranged in parallel so that switching can be performed when a filter medium is closed in order to perform continuous filtration and liquid supply, the liquid is divided and supplied, and the liquid is supplied from a jet port. A method has been proposed in which a liquid with air is circulated and returned to production. JP-A-62-2
Japanese Patent Application Publication No. 274257 proposes a device for introducing a liquid under reduced pressure into a sealed test object and degassing the liquid in order to prevent the diffusion and attenuation of the ultrasonic signal due to the presence of bubbles during the ultrasonic test. I have. JP-A-3-207439
In Japanese Patent Application Laid-Open Publication No. H11-264, a method is proposed in which gas in a flow path is eliminated before sending a coating liquid by using de-aired water and a low surface tension liquid in combination. In Japanese Patent Publication No. 2-37228, upon injecting and impregnating a synthetic resin into an impregnated material, the resin is injected under reduced pressure or normal pressure, and further, pressure change of reduced pressure → normal pressure, normal pressure → pressurized is repeated. Methods for suppressing the generation of voids have been proposed.

[0004]

However, each of the above-mentioned conventional methods has its own problems. That is, the method proposed in Japanese Patent Publication No. 58-48891 requires an additional facility for generating saturated steam under reduced pressure, and the temperature of the saturated steam is determined according to a preferred embodiment. , 10 to 20 more than the liquid to be pumped
Because of the high temperature, it not only has an unfavorable effect on the various instruments installed in the liquid feed channel, but also provides a temperature control system when the temperature of the flow channel needs to be controlled, such as a coating solution for photosensitive materials. Was to cause disturbance.

The methods proposed in Japanese Patent Publication Nos. 62-43722 and 2-49149 use only hot water for air removal.
In the method proposed in Japanese Patent No. 07439, a low surface tension liquid is used in combination, but in these cases, there is a limit to the air from which the warm water and the low surface tension liquid can be completely removed, especially to the residual air in the filter medium pores. If the liquid sent using the flow path has a high viscosity, a low surface tension, and a high flow rate, a significantly large amount of air bubbles that cannot be eliminated by hot water or a low surface tension liquid are mixed into the liquid. there were. In particular, when a filter medium with a pleated structure is used, the residual air in the folded part of the pleat is large,
The amount of air bubbles was extremely large.

The method proposed in Japanese Patent Publication No. 1-172929 requires a circulation system for returning the liquid used for air removal to the supply source in order to prevent loss of expensive liquid. A separate method and apparatus for separating and removing air bubbles mixed into the liquid are required, which complicates the entire liquid supply flow path.

In the method proposed in Japanese Patent Application Laid-Open No. 62-274257, a degassed liquid is injected into a hole to be subjected to ultrasonic inspection without introducing air bubbles. The room aims to completely fill the hole with liquid by decanting the liquid and repeating the operation of returning to normal pressure after injecting the liquid. Just repeating pressure change of normal pressure and reduced pressure after injection,
Bubbles have the effect of only being gradually dissolved in the injection liquid degassed by depressurization, and the filter medium in the liquid sending flow path requires a great deal of time.

[0008] The method proposed in Japanese Patent Publication No. 2-37228 discloses a method in which a storage container housed in a pressure vessel is used.
After injecting the synthetic resin into the material to be impregnated under normal pressure, pressurizing, returning to normal pressure, and then repeating the operation of applying pressure once or more, or performing injection under reduced pressure, returning to normal pressure, and further reducing pressure Then, the operation of returning to normal pressure is repeated once or more. This aims at dissolving or diffusing the bubbles in the resin by simply applying a pressure change to the bubbles remaining in the impregnated material which causes voids, similarly to JP-A-62-274257. However, it is difficult to change the pressure in a stationary state with a target liquid that solidifies if the liquid is kept in a flowing state in the liquid flow path, and applying a pressure change in a flowing state causes a large liquid loss. Will be. Even if it is a liquid that does not solidify, the device that pressurizes the entire flow channel becomes excessively large, and if pressurized with a general gas, this gas itself dissolves in the liquid, causing a supersaturated state, and the coating section Will cause re-precipitation of bubbles. When the pressure is reduced, foaming from the liquid itself becomes a problem.

The present invention has been made to solve the above problems and to provide a method for treating a filter medium in a liquid feed passage which can reliably prevent air bubbles from being mixed in a short processing operation using a simple apparatus. Aim.

[0010]

That is, in the method for treating a filter medium in a liquid feed channel according to the present invention, the pressure of the liquid feed channel itself is reduced, the filter medium processing liquid is filled in the liquid feed channel, and the filter material treatment is further performed. By repeating the operation of discharging the liquid one or more times, or by performing such an operation in a housing provided separately from the liquid sending flow path, the liquid sending flow path including the filter medium, or the filter medium set in the flow path Is made to have no residual air bubbles in advance, and thereafter the target liquid to be fed is immediately passed.

[0011] In the first method for treating a filter medium in a liquid feed channel according to the present invention, a pressure reducing step of reducing the pressure in the liquid feed channel in the liquid feed channel provided with the filter medium, It is characterized by having a liquid filling step of filling the filter medium treatment liquid into the liquid flow path, and a liquid discharging step of discharging the filter medium treatment liquid filled in the liquid filling step to the outside of the liquid supply flow path. .

In the first method for treating a filter medium in the liquid-feeding channel according to the present invention, when the filter-material processing solution is filled in the liquid-feeding channel under reduced pressure, the filter material-treating liquid enters the inside of the filter material. Unremovable air remains in the pores of the filter medium. Next, when the filled filter medium treatment liquid is discharged, a part of the filter medium treatment liquid remains near the pores and inside the pores, and a part of the pores becomes wet. When the filter medium treatment liquid is refilled in this state, some of the pores are already wet, so it is easy to get wet, and the air once exhausted by the reduced pressure re-enters the closed gap that is wet. Since the pores are difficult to fill, the pores are filled with the filter medium treatment liquid. By repeating this operation,
All pores can be filled with the filter medium treatment liquid in a short time. Therefore, no bubbles are mixed into the liquid to be sent after the filling of the filter medium processing liquid.

According to the second method for treating a filter medium in the liquid feed channel according to the present invention, there is provided a housing in which a filter medium is detachably mounted, a filter medium mounting step of mounting the filter medium in the housing, a depressurizing step of depressurizing the inside of the housing, A liquid filling step of filling the filter medium processing liquid into the housing decompressed in the pressure reducing step, a liquid discharging step of discharging the filter medium processing liquid filled in the liquid filling step to the outside of the housing, and removing the filter medium from the housing And a filter medium attaching step of attaching the filter medium taken out in the filter medium taking-out step to the liquid sending flow path.

In the filter material processing method in the second liquid feed passage according to the present invention, when the housing under reduced pressure is filled with the filter medium processing liquid, the filter medium processing liquid enters the inside of the filter medium, but the filter medium becomes empty. Unremovable air remains in the holes. Next, when the filled filter medium treatment liquid is discharged, a part of the filter medium treatment liquid remains near the pores and inside the pores, and a part of the pores becomes wet. When the filter medium treatment liquid is refilled in this state, some of the holes are already wet, so it is easy to get wet, and the air exhausted by the reduced pressure flows back into the wet and closed gap. Since it is difficult, the pores are filled with the filter medium treatment liquid. When the filter medium in this state is attached to the liquid sending flow path, bubbles are not mixed into the liquid sending liquid even when the liquid sending liquid is passed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a method for treating a filter medium in a first liquid feed channel will be described. The depressurizing step is a step of depressurizing the inside of the liquid sending flow path. The degree of depressurization does not need to be reduced until a high vacuum is achieved, but is preferably 200 Torr or less, more preferably 50 Torr or less.
The pressure reducing device is not particularly limited, and a conventionally known pressure reducing pump can be used.

In the liquid filling step, a filter medium treatment liquid is filled in the liquid sending flow path, and the filter medium treatment liquid is water or warm water, a low surface tension liquid, for example, an aqueous solution of a surfactant, an organic solvent (such as alcohol) or the like. And an aqueous solution thereof, or the liquid itself to be sent in the liquid sending channel. Further, the filter medium treatment liquid is preferably degassed in advance.

In the liquid discharging step, the filter medium processing liquid is discharged from the inside of the liquid sending flow path. Even if the filter medium processing liquid is discarded from the liquid sending flow path to the outside, the liquid sending flow path is reversely fed to the filter medium processing liquid. May be returned to the supply source, and in any case, it is sufficient that the inside of the liquid sending flow path can be emptied.

The above-described pressure reduction step, liquid filling step and liquid discharging step are performed at least once.
It is preferably performed 10 times continuously, and may be performed 20 times depending on the size of the pores. After going through such a process,
The operation stops after the final liquid filling step has been performed,
This is to fill the filter medium processing liquid into the liquid sending flow path, and the filter medium processing liquid to be used is the same as in the initial liquid filling step.
Alternatively, if the initial filter medium processing liquid has a low affinity with the original liquid sending liquid, a liquid with a high affinity may be used as the filter medium processing liquid for final filling. After the filling of the filter medium treatment liquid in the final liquid filling step, the flow of the liquid-feed liquid, which is originally intended for conveyance, is started.

The filter medium used in the method for treating a filter medium in the liquid feed channel of the present invention is not particularly limited, and a conventionally known filter medium can be used. In the case of a cartridge-type filter medium with a pleated structure, the filter medium itself is deformed to expand the pores and facilitate the penetration of the filter medium treatment liquid into the pores. preferable. In the case of a filter medium having no pleated structure, there is no need to particularly determine the direction of pressure reduction.

Next, a method of treating the filter medium in the second liquid feed channel will be described. The filter medium processing method in the second liquid supply flow path is to process the filter medium offline, prepare a housing for processing the filter medium, fill the pores of the filter medium with the filter medium processing liquid in this housing, A filter medium filled with a filter medium treatment liquid is attached to a liquid sending flow path.

The processing of the filter medium in the housing is the same as the method of processing the filter medium in the first liquid-feeding channel. After attaching this processed filter medium to the liquid-feeding channel, the liquid-feeding liquid is passed. It is possible to prevent air bubbles from entering due to the filter medium. In addition, when the treated filter medium is attached to the liquid sending flow path, it is preferable that the liquid sending flow path is previously filled with the filter medium treatment liquid.

[0022] The first method for treating the filter medium in the liquid feed channel is as follows.
It is possible to remove not only the filter medium but also the air remaining in the gap (scratch etc.) due to other factors in the liquid sending flow path.
In this regard, the processing method of the first liquid flow path is more preferable than the filter material processing method of the second liquid flow path.

[0023] The method for treating a filter medium in a liquid sending channel according to the present invention comprises:
It can be used in various productions in which bubbles are preferably not mixed in the liquid to be sent. For example, it can be used irrespective of the coating method itself, such as an emulsion coating process in the production of photosensitive materials, a photoresist coating process for optical recording materials, etc. Things.

Further, the method for treating a filter medium in a liquid sending channel according to the present invention can be used also in a semiconductor manufacturing process. That is, in the semiconductor manufacturing process, particles in pure water are measured for quality control of the pure water. And
Usually, it is necessary to remove foreign substances and bacteria in this flow path, so a filter medium for performing fine filtration is mounted. However, if air bubbles flow out of the filter medium, it will cause an error in particle measurement, so that it is necessary to prevent air bubbles from being mixed. Therefore, by using the method for treating a filter medium in the liquid-feeding channel according to the present invention, counting errors due to bubbles can be prevented.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for treating a filter medium in a liquid feed channel according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a coating apparatus that performs a filter material processing method in a first liquid sending flow path,
FIG. 2 is a schematic cross-sectional view of a filter medium used in the filter medium processing method, and FIG.
FIG. 4 is a schematic cross-sectional view illustrating a form of the filter medium at atmospheric pressure, and FIG. 4 is a schematic cross-sectional view illustrating a form in which the outside of the filter medium is depressurized.

In FIG. 1, reference numeral 1 denotes a liquid storage tank in which a coating liquid as a liquid to be sent is stored.
Is connected to a filter medium housing 3 via a liquid feed pump 2, and a filter medium 4 is mounted in the filter medium housing 3.
A three-way valve 5 is provided between the liquid storage tank 1 and the liquid sending pump 2. The three-way valve 5 is provided with a filter medium treatment liquid tank 6 storing hot water as a filter medium treatment liquid via a valve 13. The drainage pipe 7 is connected via the valve 6 while being connected. A defoaming section 8, a valve 9 and a coating section 10 are connected to the filter medium housing 3, and a valve 1 is provided between the defoaming section 8 and the valve 9.
The vacuum pump 12 is connected via 1.

As shown in FIG. 2, the filter medium 4 comprises a core member 41 and a pleated portion 42 provided on an outer peripheral surface of the core member 41. The pleated portion 42 can be freely opened and closed. I have.

In the above-described coating apparatus, in order to carry out the method for treating a filter medium in a liquid feed channel according to the present invention, first, the liquid feed pipe, the filter medium housing 3 and the defoaming section 8 are depressurized by a vacuum pump 11 ( Decompression step). At this time, in the environment of the atmospheric pressure before the pressure reduction, the pleated portion 42 is in the closed state as shown in FIG. 3, but in the environment where the filter medium is wet and the pressure is reduced, As shown in FIG.
The pleated portion 42 is open outward. In this state, the valve 13 is opened, and the hot water stored in the filter medium treatment liquid tank 6 is filled into the liquid sending pipe and the filter medium housing 3 via the liquid sending pump 2 (liquid filling step). Then, since the pleated portion 42 of the filter medium 4 is open, warm water enters the inside and enters the pores or wets the surroundings, and warm water enters the scratches of the liquid supply pipe or wets the surroundings. Becomes

Next, the filled hot water is discharged from the drain pipe 7 (treatment liquid discharging step), and then, after the pressure is reduced again, the hot water is filled into the liquid sending pipe and the housing 3 (final liquid filling step). Then, since the pores of the filter medium 4 and the scratches of the liquid feed pipe are already in a wet state, warm water easily enters, and the pores of the filter medium, the scratches of the liquid feed pipe and the like are filled with hot water.

In this state, when the flow of the coating liquid in the liquid storage tank 1 is started, the coating liquid is sent without being mixed with air bubbles, and the air bubbles mixed by other causes are removed in the defoaming section 8. Then, it is sent to the coating unit 10. Therefore, a good product can be obtained without causing defects due to bubbles in the application section 10.

FIG. 5 is a schematic diagram of an apparatus for performing the method for treating a filter medium in the second liquid-feeding channel. In this figure, 5
Reference numeral 1 denotes a filter medium processing liquid tank in which warm water as a filter medium processing liquid is stored. The filter medium processing liquid tank 51 is connected to a filter medium housing 54 via a three-way valve 52 and a liquid feed pump 53. The filter medium housing 54 is configured such that the filter medium 55 can be detachably mounted. A vacuum pump 57 is connected to the filter medium housing 54 via a valve 56.
A drain pipe 58 and a valve 59 are connected to one of the three-way valves 52.

In the apparatus as described above, in order to carry out the method for treating a filter medium in the liquid feed channel according to the present invention, first,
The filter medium 55 is mounted on the filter medium housing 54 (filter medium mounting step), and the inside of the filter medium housing 54 is depressurized by the vacuum pump 57 (decompression step). Next, hot water in the filter medium processing liquid tank 51 is filled in the filter medium housing 54 (liquid filling step), and pores of the filter medium 55 are filled with hot water, and then the hot water is discharged from the drain pipe 58 and the valve 59 (liquid discharging step). ) Then, after the pressure is reduced, the warm water is filled again into the filter medium housing 54 (final liquid filling step).

Then, the filter medium 55 is connected to the filter medium housing 5.
4 (filter material removal step), and the filter medium is mounted on a filter medium housing in a predetermined liquid supply flow path (filter material mounting step). Thereafter, as in the conventional case, the liquid to be fed is passed, and for example, a coating process is performed.

[0034]

Since the present invention has the above-described structure, it has the following effects. (1) With a simple structure and operation, it is possible to prevent bubbles from being mixed in the liquid to be sent. In other words, no special low surface tension liquid or ancillary equipment for its preparation is required, and a simple decompression device needs only to be added to the liquid sending flow path, and a rinsing operation is not required. (2) Since the switching time for replacing the filter medium is reduced from 1/10 to 1/20 of the conventional one, the production efficiency can be improved. (3) Even in the initial stage of the use of the filter medium, it is possible to eliminate any bubbles mixed into the liquid to be sent and to reduce liquid loss. (4) For the treatment of residual air bubbles brought in from the filter media,
Although a relatively large defoaming device has been required, the defoaming device can be reduced in size by eliminating this mixed air bubble.

[Brief description of the drawings]

FIG. 1 is a schematic view of a coating apparatus for performing a first method for treating a filter medium in a liquid-feeding channel according to the present invention.

FIG. 2 is a schematic cross-sectional view of a filter medium used in the same method for treating a filter medium.

FIG. 3 is a schematic cross-sectional view showing a form at atmospheric pressure of a filter medium used in the filter medium treatment method.

FIG. 4 is a schematic cross-sectional view showing a state where the outside of the filter medium used in the method for treating a filter medium is depressurized.

FIG. 5 is a schematic view of an apparatus for carrying out a second method for treating a filter medium in a liquid sending channel according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Liquid storage tank 2 ... Liquid feed pump 3 ... Filter medium housing 4 ... Filter medium 42 ... Pleated part 6 ... Filter medium processing liquid tank 7 ... Drainage pipe 8 ... Defoaming part 10 ... Application part 12 ... Vacuum pump 51 ... Filter medium processing liquid tank 53: liquid feed pump 54: filter medium housing 55: filter medium 57: vacuum pump

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) B05D 3/00 B01D 29/06 510A 510C 29/42 510

Claims (3)

[Claims] 1. A depressurizing step of depressurizing a liquid-feeding channel in a liquid-feeding channel provided with a filter medium, and a liquid filling step of filling a filter-media treatment liquid into the liquid-feeding channel depressurized in the depressurizing step. When,
A liquid discharging step of discharging the filter medium processing liquid filled in the liquid filling step to the outside of the liquid sending flow path. 2. A housing in which a filter medium is removably mounted, a filter medium mounting step of mounting the filter medium on the housing, a depressurizing step of depressurizing the inside of the housing, and a filtering medium treatment liquid in the housing depressurized in the depressurizing step. A liquid filling step of filling, a liquid discharging step of discharging the filter medium treatment liquid filled in the liquid filling step to the outside of the housing, a filter medium removing step of removing the filter medium from the housing, and a flow of the filter medium removed in the filter medium removing step. And a method of attaching a filter medium to a channel. 3. The method according to claim 1, wherein the filter medium is a filter medium having a pleated structure, and the pressure inside the filter medium is reduced in the pressure reducing step.