JPH0824772A - Method for cleaning inside of lip of mouthpiece of curtain flow coater and production of coating film for color film - Google Patents

Abstract

PURPOSE:To easily clean the inside of the lip in the mouthpiece of a curtain flow coater used in coating a flat sheet with paint and to obtain the coating film for a color filter excellent in quality and economics by using a cleaning member consisting of film. CONSTITUTION:A paint 9 is supplied into the mouthpiece 3 from a paint feed pipeline 7 with a pump 8. Under such conditions, the foreign matter deposited in a lip 4 in the mouthpiece 3 is cleaned off with a cleaning member 5 fixed to a support 6 and consisting of film, and the paint 9 is applied as a curtain from the lip 4 as the tip of the mouthpiece 3 onto a flat sheet 1 sucked and fixed on a suction sheet 1 sucked and fixed on a suction stage 2 as the flat sheet 1 is transported A to form a coating film. Consequently, the foreign matter deposited in the lip is easily cleaned off, and the coating film for a color filter without any streak and excellent in quality and economics is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cleaning of the inside of a lip of a die of a curtain flow coater which is particularly suitable for applying a coating film for a color filter used for a color display using a liquid crystal or a solid-state image pickup device. The present invention relates to a method and a method for producing a color filter coating film using the method.

[0002]

2. Description of the Related Art Generally, a color filter used for a display using liquid crystal is arranged on a transparent substrate such as a glass plate so that three primary color patterns of red, green and blue are arranged in a fixed positional relationship. There is. There is a curtain flow coater as one of the thin film coating methods for the glass substrate and the like. This coating method is disclosed in, for example, Japanese Patent Application Laid-Open No. 5-11105, and a method in which a coating material is discharged in a curtain shape from the tip of a lip portion of a die called a slit die, a die head, and a T die, and is applied in a non-contact manner to a substrate. belongs to. This system is characterized in that the change in the viscosity of the paint is small and the coating film thickness is uniform because the paint supply path until it is discharged is closed.

[0003]

However, the drawback of this coating method is that the lip interval of the die is 50 to 150 .mu.m.
Since it is as narrow as m, a part of the inside of the lip is clogged when pigment agglomerates, which are one of the paint components, and mixed foreign substances other than the pigment are discharged from the die together with the paint. It is likely to occur as streaks.

Therefore, it is an object of the present invention to maintain the characteristics of the conventional curtain flow coater such as a change in the viscosity of the coating and a uniform coating film thickness, while maintaining the inside of the lip of the mouthpiece, which has been a problem to date. (EN) Provided is a method for cleaning a die of a curtain flow coater, which can easily clean foreign matter attached to a coating material and can provide a coating film for a color filter having no coating stripe and excellent in quality and economy.

[0005]

The present invention has the following configuration.

[0006] In a method of cleaning the inside of the lip of a die of a curtain flow coater used when applying a coating material on a flat plate, the inside of the lip of the die is cleaned using a cleaning member made of a film. How to clean the inside of the coater lip.

In a method for producing a coating film for a color filter including a step of applying a coating material for forming a coating film for a color filter on a transparent flat plate by using a curtain flow coater, the inside of a lip of a die of the curtain flow coater is made of a film. A method for producing a coating film for a color filter, comprising a step of cleaning using a cleaning member.

Next, a method of cleaning the inside of the lip of the die of the curtain flow coater according to the present invention will be described with reference to the drawings.

1, FIG. 2, FIG. 3 and FIG. 4 are schematic views showing an example of coating by a curtain flow coater (slit die coater) according to the present invention. That is, FIGS. 1 and 2 show a state in which the inside of the lip 4 of the mouthpiece 3 is cleaned by the cleaning member 5 immediately before applying the paint, and FIGS. 3 and 4 show the inside of the lip 4 of the mouthpiece 3. Shows the state where the cleaning is completed and the application of paint is started. 1 and 3
2 is a view seen from a direction perpendicular to the conveyance direction of the flat plate.
4 and FIG. 4 are views seen from the transport direction of the flat plate.

That is, the paint 9 is supplied to the inside of the base 3 from the paint supply pipe 7 by the pump 8. In this state, the cleaning member 5 cleans the foreign matter adhering to the inside of the lip 4 of the mouthpiece 3. Subsequently, as the flat plate 1 is conveyed (in the direction of arrow A), the coating is applied from the lip 4 which is the tip of the die 3 to the flat plate 1 which is suction-fixed on the suction stage 2 in a curtain state, and a coating film 10 is formed. . The uniformity of the coating film is controlled by adjusting the distance between the lips 4 at the tip of the die and the distance between the flat plate 1 and the lips 4 when the coating material is discharged in a curtain shape.

An example of the cleaning procedure will be described with reference to FIG. That is, the cleaning member 5 is fixed by the support member (jig or the like) 6, and the cleaning device (the cleaning member 5 and the support member 6) moves in the state where the cleaning member 5 enters the lip 4 of the mouthpiece 3. Return to B along and complete the cleaning. However, the present invention is not limited to this, and the cleaning member 5 may not be fixed by the support.

Examples of the cleaning method include a method in which a cleaning member is inserted into the mouthpiece lip for manual cleaning, and a method in which a cleaning member fixed to a support is used for automatic cleaning.
Manual cleaning has a problem in that it takes time in a work process and the substrate is contaminated by dust generated from a human body, which may cause foreign matter in the coating film. Therefore, automatic cleaning is preferable.

The cleaning member 5 is made of a film, and a film made of Teflon, polyester, polypropylene, polyimide or the like is preferably used. An example of the cleaning member 5 is shown in FIG. 5, but the thickness of the film is preferably 10 to 25 μm narrower than the distance between the tips of the lips 4. If it is thinner than this, the cleaning effect is low, and if it is thicker than this, the film does not enter the inside of the lip.

The cleaning by the cleaning member is most effective if it is carried out immediately before the coating of the coating material, because most of the coating material and the foreign matter adhering to the inside of the lip of the die are removed. You can

The coating by the curtain flow coater of the present invention is not limited to the method using the slit die coater, but may be a method using a die head, a T-die or the like. Further, the paint supply means is not limited to the pump, and may be a method such as compressed air.

When the paint is a paint for forming a paint film for a color filter, it is particularly required that the appearance of the paint film is good. Therefore, the method for cleaning the inside of the lip of the die of the curtain flow coater of the present invention is Particularly preferably used.

The case of applying the method for cleaning the inside of the lip of the die of the present invention to the formation of a color filter coating film will be described below.

When forming a coating film for a color filter, a transparent flat plate is used. The transparent flat plate is not particularly limited, but a transparent flat plate having a total light transmittance of 70% or more, such as a plastic flat plate made of polycarbonate, polymethylmethacrylate or the like, a plastic film or a glass plate is preferably used. Of these, a glass plate is more preferably used.

The type of coating material is not particularly limited, but one or a mixture of two or more of acrylic resin, polyester resin, polyvinyl alcohol resin, polyamic acid resin, polyimide resin, etc., and photosensitive resin thereof, etc. may be used. It is preferably used. In addition, a colorant such as a dye or a pigment may be dispersed and mixed with these resins before use.

The film thickness after coating on a transparent flat plate is not particularly limited, but is 0.1 μm to 5 μm in the state of a dry coating film.
The range of m is preferable, and more preferably 0.2 μm to 3
The range of μm is preferably used. The coating film after drying is 0.1
If it is less than μm, vertical streaks are generated in the dried coating film, which is a quality problem. On the other hand, if it exceeds 5 μm, the amount of paint used increases, and the economy is poor.

The method of manufacturing the color filter includes, for example, the following methods, but is not limited to these. First, a light shielding layer having a fine pattern is formed on a transparent flat plate. A thermosetting paint containing a colorant is applied onto the light-shielding layer and dried at a temperature of 50 ° C. to 150 ° C. to form a thermosetting coating film. Subsequently, a positive photoresist is applied on the thermosetting coating film, mask exposure is performed using an ultrahigh pressure mercury lamp or the like, and then the positive photoresist is developed and etched to form a relief pattern, The thermosetting coating film is etched using the relief pattern as a mask. Then, after peeling off the positive photoresist, the coating film is heat-baked at 200 ° C. to 350 ° C. to thermally cure the coating film. The above steps are repeated for red, green, and blue to form predetermined red, green, and blue fine patterns to form a color filter.

The drying temperature of the coating material is preferably in the range of 50 ° C to 160 ° C, more preferably 80 ° C to 130 ° C. If the temperature is lower than 50 ° C, the drying time will be long and the production efficiency will be poor. On the other hand, when the temperature exceeds 160 ° C., thermosetting proceeds and becomes insoluble in the developing solution.

On the other hand, in the case of a photosensitive coating containing a colorant, a light-shielding layer having a fine pattern is formed on a transparent flat plate, the photosensitive coating containing a colorant is applied on the light-shielding layer, and the temperature is 50 ° C. Dry at a temperature of ~ 150 ° C to form a photosensitive coating. Subsequently, mask exposure is performed using an ultra-high pressure mercury lamp or the like to photo-cur the photosensitive coating film. Then, the uncured photosensitive coating film on the light shielding layer is developed and etched. The above steps are repeated for red, green, and blue to form predetermined red, green, and blue fine patterns to form a color filter.

If necessary, a paint containing no colorant may be applied to the red, green and blue fine patterns to form a protective film and a smoothness to form a color filter.

The method for cleaning the inside of the lip of the die of the curtain flow coater according to the present invention is effective for applying the coating material for forming a coating film for various color filters in the above color filter manufacturing process. That is, a red, green, and blue fine pattern forming paint, a light shielding layer forming paint, a protective film forming paint, and the like.

[0026]

The present invention will be described in detail below with reference to examples, but the invention is not limited thereto.

Example 1, Comparative Example 1 Using the coating apparatus shown in FIGS. 1, 2, 3 and 4,
The paint was applied on a glass substrate. A glass substrate having a size of 300 mm × 350 mm and a thickness of 1.1 mm was used, and the inside of the lip 4 of the die 3 was cleaned with the cleaning member 5 immediately before coating. After that, a polyamic acid paint in which an N-methylpyrrolidone solvent, a salt-brominated phthalcyanine green (CI Pigment Green 36), and a disazo yellow HR (CI Pigment Yellow 83) pigment were added and dispersed was added, and the solid content was 8 wt%. 2 at a viscosity of 100 cp
It was applied at a speed of m / min and dried at 120 ° C. for 10 minutes. As the cleaning member 5, a polyester film having a thickness of 100 μm is formed in such a shape as to come into contact with the inside of the lip of the die, and the width is 15 m.
m (Examples 1 and 2). As a result of automatic cleaning (Embodiment 1) and manual cleaning (Embodiment 2) of every 50 glass substrates by the above method and continuously applying 1000 sheets, foreign matters are very little adhered inside the lip portion after cleaning. All of the obtained coated substrates were free from vertical stripes and contamination by dust, etc., and good coating films were obtained.

On the other hand, application was carried out in the same manner as in Examples 1 and 2 without using the cleaning member of the present invention (Comparative Example 1). Table 1 shows the results of visual evaluation of the appearance of the coating films of the coated substrates obtained in Examples 1 and 2 and the coated substrate obtained in Comparative Example 1 for comparison.

[0029]

[Table 1] In Comparative Example 1, as the number of coatings increases, the foreign matter adhered inside the lip of the die contaminates. As a result, the generation of vertical stripes and the amount of foreign matter due to human body dust increase. On the other hand, in Example 1, such a phenomenon did not occur, and a good coated substrate having no problem in appearance was obtained. Further, in Example 2, although some foreign matter was attached, it was within a range where there was no practical problem.

[0030]

According to the present invention, it is possible to reliably remove a pigment aggregate which is one of the paint components adhering to the inside of the lip of the die and a foreign substance mixed in other than the pigment. Therefore,
The appearance of defects such as vertical stripes, uneven coating and stains due to pigments does not occur on the coating film on the flat plate, and the productivity can be remarkably improved.

Further, by performing the cleaning automatically, it is possible to surely prevent the appearance defect due to the contamination of foreign substances due to the dust generation of the human body.

Since the color filter coating film is required to have a particularly good appearance, this cleaning method is particularly effective when the color filter coating film is formed by a curtain flow coater.

Therefore, it is possible to continuously produce a color filter which is high in quality, low in cost and excellent in economic efficiency.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of coating by a curtain flow coater (slit die coater) according to the present invention,
It is the figure which looked at the state which is cleaning the inside of the mouthpiece by the cleaning member just before applying paint from the direction perpendicular to the conveyance direction of a flat plate.

FIG. 2 is a schematic view showing an example of coating by a curtain flow coater (slit die coater) according to the present invention,
It is the figure which looked at the state where the inside of the mouthpiece was cleaned by the cleaning member just before applying paint from the conveyance direction of the flat plate.

FIG. 3 is a schematic view showing an example of coating by a curtain flow coater (slit die coater) according to the present invention,
It is the figure which looked at the state where cleaning of the inside of the lip of the mouthpiece was completed and application of paint was started from the direction perpendicular to the transport direction of the flat plate.

FIG. 4 is a schematic view showing an example of coating by a curtain flow coater (slit die coater) according to the present invention,
It is the figure which looked at the state where the cleaning of the inside of the lip of the mouthpiece was completed and the application of the paint was started from the conveyance direction of the flat plate.

FIG. 5 is a schematic view showing an example of a cleaning member for cleaning the inside of the lip of the die of the curtain flow coater.

[Explanation of symbols]

 1: Flat plate 2: Suction stage 3: Base 4: Lip 5: Cleaning member 6: Support for cleaning member 7: Paint supply pipe 8: Pump 9: Paint 10: Paint film

Claims (7)

[Claims] 1. A method for cleaning the inside of the lip of a die of a curtain flow coater used when applying paint on a flat plate, wherein the inside of the lip of the die is cleaned using a cleaning member made of a film. How to clean the inside of the lip of the curtain flow coater. 2. The method for cleaning the inside of the lip of the mouthpiece of a curtain flow coater according to claim 1, wherein the cleaning member is made of a film and fixed to a support to clean the cleaning member. 3. The cleaning of the inside of the lip of the base of the curtain flow coater according to claim 1, wherein the inside of the lip of the base of the curtain flow coater is cleaned immediately before the coating of the paint on the flat plate with the curtain flow coater. Method. 4. The method for cleaning the inside of the lip of the die of a curtain flow coater according to claim 1, wherein the paint is a paint for forming a coating film for a color filter. 5. A method for producing a coating film for a color filter, comprising the step of applying a coating material for forming a coating film for a color filter onto a transparent flat plate by using a curtain flow coater, wherein a film is formed inside the lip of the die of the curtain flow coater. A method for producing a coating film for a color filter, comprising the step of cleaning using a cleaning member consisting of. 6. The method for producing a coating film for a color filter according to claim 5, wherein cleaning is performed using a cleaning device in which a cleaning member made of a film is fixed by a support. 7. The color filter according to claim 5, wherein the inside of the lip of the die of the curtain flow coater is cleaned immediately before applying the coating material for forming a color filter coating film on the transparent flat plate with the curtain flow coater. Of manufacturing coating film for automobile.