JPH0852404A - Curtain flow coater, coating method using the same, and manufacturing method of coating film for color filter - Google Patents

Abstract

(57) [Summary] [Construction] According to the present invention, in the shape of the die lip portion of the curtain flow coater, only the tip of the backup lip is parallel to the substrate, and the die shape and coating using the same. Is the way. [Effect] According to the present invention, the doctor lip portion of the die has a predetermined angle, and the backup lip portion has a shape parallel to the substrate, so that the film thickness can be made uniform from the coating start portion. . Furthermore, it has become possible to obtain a good coating appearance without unevenness or streaks.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curtain flow coater suitable for forming a coating film for a color filter, which is used for a color display using a liquid crystal, a solid-state image pickup device, etc., a coating method using the same, and The present invention relates to a method for manufacturing a color filter coating film.

[0002]

2. Description of the Related Art In general, a color filter used for a display using liquid crystal is arranged on a transparent substrate such as a glass substrate with a pattern of three primary colors of red, green and blue arranged in a fixed positional relationship. There is. A curtain flow coater is one of the thin film coating methods on the transparent substrate.

As this coating method, for example, Japanese Unexamined Patent Publication No.
It is disclosed in Japanese Laid-Open Patent Publication No. 11105, and is a system in which a paint is ejected in a curtain shape from a lip end of a die called a die head, a T die, and a slit die, and is applied to a substrate in a non-contact manner. This method is characterized in that the paint supply path until it is discharged is sealed, so that foreign matter is less mixed in and the viscosity of the paint is less likely to change.

However, in the thin film coating by the curtain flow coater, the film thickness accuracy is poor for several meters at the coating start portion and the film tends to be thin. For this reason, it has been difficult to apply a thin film to a small flat plate. However,
In the case of a color filter, in coating on a flat plate, obtaining a product having a uniform film thickness from the coating start portion is an essential problem in terms of quality.

As a means for improving the film thickness uniformity at the coating start portion, there is optimization of the die shape. The T-die is generally used as the present die shape. The T-die has a large liquid pool at the tip of the lip, and it takes time to form a stable liquid pool. Therefore, there are problems that the film thickness stability at the coating start portion is poor, and coating defects such as vertical stripes are likely to occur.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to make it possible to achieve a uniform film thickness at the coating start portion, which has been a subject of the curtain flow coater.

[0007]

The present invention has the following configuration.

(1) A curtain flow coater used when applying a coating material on a flat plate, wherein the angle of the tip of at least one of the doctor lip portion and the backup lip portion of the die of the curtain flow coater is less than 90 degrees. A curtain flow coater characterized by being present.

(2) In a method of applying a coating material on a flat plate using a curtain flow coater, at least one tip of a doctor lip portion and a backup lip portion of a die of the curtain flow coater is not parallel to the flat plate. A method for applying a paint, characterized by applying.

(3) In a method for producing a coating film for a color filter, which comprises a step of applying a coating material for forming a coating film for a color filter onto a flat plate using a curtain flow coater, a doctor lip portion of a die of the curtain flow coater and A method for producing a coating film for a color filter, characterized in that at least one tip of the backup lip portion is applied in a state not parallel to the flat plate.

The curtain flow coater of the present invention will be described.

The die of the curtain flow coater according to the present invention is characterized in that the tip of at least one of the doctor lip portion and the backup lip portion is less than 90 degrees. This is because the film thickness at the coating start portion is not stable when the tips of both lip portions are 90 degrees. In order to further improve the stability of the film thickness at the coating start portion, it is preferable that the angle of the tip of the doctor lip is less than 90 degrees and the angle of the tip of the backup lip is 90 degrees. The angle of the tip of the doctor lip is more preferably 30 to 80 degrees, and even more preferably 40 to 70 degrees. If it is less than 30 degrees, the amount of liquid pool at the tip of the lip portion increases and the film thickness at the coating start portion becomes thin. Further, if it exceeds 80 degrees, the shape becomes almost the same as that of the T-die, so that the film thickness uniformity at the coating start portion is insufficient. On the other hand, the angle of the tip of the backup lip portion is preferably substantially 90 degrees, and it is preferable that the backup lip portion is applied in a state parallel to the flat plate on which the paint is applied. If there is no portion parallel to this substrate, the liquid pool at the tip of the lip will not be stable when the coating material is applied, and thus uneven coating in the width direction is likely to occur. The length of the part parallel to this flat plate is 0.5 ~
20 mm range is preferable, more preferably 1-5 mm
Is preferred. If it is less than 0.5 mm, coating unevenness in the width direction tends to occur, and if it exceeds 20 mm, the die becomes heavy and the die is bent, and the clearance with the substrate cannot be kept constant. Lacks sex.

FIG. 2 is a schematic view showing an example of a die of the curtain flow coater according to the present invention. That is, the tip of the mouthpiece 6 is composed of the doctor lip 12 and the backup lip 13, the angle of the tip of the doctor lip 12 is about 50 degrees, and the angle of the tip of the backup lip 13 is substantially 90 degrees. There is. In addition, 7 represents a push-pull bolt, and 11 represents a film.

Next, the coating method of the present invention will be described.

The coating method of the present invention is a method of coating a flat plate with the curtain flow coater as described above. Alternatively, it is a method of applying the paint in a state where at least one tip of the doctor lip portion and the backup lip portion of the die of the curtain flow coater is not parallel to the flat plate. In order to improve the film thickness stability of the coating start portion, it is preferable that the doctor lip portion is not parallel to the flat plate and the backup lip portion is parallel to the flat plate.

FIG. 1 is a schematic view showing an example of coating with a curtain flow coater (slit die coater) according to the present invention. That is, the paint 10 is supplied from the pipe 8 to the inside of the mouthpiece 6 by the pump 9, and the lip 5 (the doctor lip 12 and the backup lip 13) which is the tip of the mouthpiece 6 is formed in accordance with the conveyance of the flat plate 1 (direction of arrow A). From the above), it is applied in a curtain state on the flat plate 1 suction-fixed on the suction stage 2 to form a coating film 3. The uniformity of the coating film in the width direction is controlled by adjusting the distance between the lip 5 at the tip of the die and the distance between the flat plate 1 and the lip, that is, the clearance 4 for the paint discharged in a curtain shape.

The coating of the coating material 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 a 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 paint film has a good appearance. Therefore, the method for applying the paint by the curtain flow coater of the present invention is particularly suitable. Used.

The case where the coating method of the present invention is applied 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, a glass plate or the like 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 and the like, and photosensitive resins thereof are used. Etc. are preferably used. A coloring material such as a dye or a pigment may be dispersed and mixed with these resins before use.

The film thickness after coating on the transparent flat plate is not particularly limited, but it is 0.1-5.
The range is preferably 0 μm, more preferably 0.2 to
A range of 3.0 μm is preferably used. If the coating film after drying is less than 0.1 μm, vertical streaks occur in the dried coating film,
This is a quality problem. On the other hand, when it exceeds 5.0 μm, the smoothness of the dried coating film is poor. In addition, the amount of paint used increases, which is not economical.

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 to which an adhesive is added is applied onto the light shielding layer and dried at a temperature of 50 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 ultra-high pressure mercury lamp or the like, and then the thermosetting coating film is etched using the relief pattern as a mask.
Then, after removing the positive type photoresist,
The coated film is heat-cured by heating to 350 ° C. Repeat the above steps for red, green and blue,
Fine patterns of green and blue are formed to serve as color filters.

The drying temperature of the coating material is preferably in the range of 50 to 160 ° C, more preferably in the range of 80 to 130 ° C. If it is less than 50 ° C, the drying time is long and the production efficiency is poor. On the other hand, when the temperature is 160 ° C. or higher, thermosetting progresses and becomes insoluble in the developer.

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, and the photosensitive coating containing a colorant is applied onto the light-shielding layer, and the coating is applied at 50 to 50%. Dry at a temperature of 150 ° C. to form a photosensitive coating film. Subsequently, mask exposure is performed using an ultra-high pressure mercury lamp or the like to photo-cur the photosensitive coating. 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 a predetermined red, green and blue fine pattern to form a color filter.

If necessary, a colorant-free paint may be applied to the red, green and blue fine patterns to form a protective film and a colorant-free paint for the purpose of improving smoothness.

The coating material coating method according to the present invention is effective for coating a coating material for forming a coating film for various coating materials in the above color filter manufacturing process. That is, it is a red, green or blue fine pattern forming paint, a light shielding layer forming paint, a protective layer forming paint or the like.

[0028]

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 Coating was carried out on a glass substrate using the coating apparatus and the die shown in FIGS. 1 and 2. A glass substrate having a size of 300 × 400 mm and a thickness of 1.1 mm was used. As the paint, a polyamic acid paint in which N-methylpyrrolidone solvent, chlorobrominated phthalcyanine green (CI Pigment Green 36) and disazo yellow HR (CI PI Pigment Yellow 83) pigment were added and dispersed was solidified. Min 8wt%, viscosity 100cp,
The coating was performed at a coating speed of 2 m / min and dried at 120 ° C. for 10 minutes.

On the other hand, using the conventional curtain flow coater shown in FIG. 3 (the tips of the doctor lip and the backup lip are 90 degrees and both tips are parallel to the flat plate), the same as in Example 1 is used. Application was performed by the method (Comparative Example 1).

FIG. 4 shows the film thickness distribution results of the coated substrate obtained in Example 1 and the coated substrate obtained in Comparative Example 1 for comparison.

In Comparative Example 1, the film thickness is thin from the coating start portion to 200 mm with respect to the central portion of the coated substrate, and the film thickness is not uniform. On the other hand, in Example 1, the film thickness distribution is not the same as in Comparative Example 1, and the film thickness is already stable 10 mm from the coating start portion. Further, there was no coating unevenness during coating, and a good coating film was obtained.

[0033]

The curtain flow coater according to the present invention,
By applying the coating method, it is possible to remarkably improve the film thickness uniformity from the coating start part, so vertical stripes at the time of coating that have occurred in the past are hardly generated, and a high quality coating film can be obtained. Obtainable. Therefore, when forming a coating film for a color filter that is required to have a good appearance, particularly preferably for single-wafer coating where stability of the film thickness from the coating start portion is required You can

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of coating by a curtain flow coater according to the present invention.

FIG. 2 is a schematic view showing an example of a die of a curtain flow coater according to the present invention.

FIG. 3 is a schematic diagram showing an example of a die of a conventional curtain flow coater.

FIG. 4 is a film thickness distribution diagram of a coated substrate obtained in Example 1 and a coated substrate obtained in Comparative Example 1.

[Explanation of symbols]

 1: Flat plate 2: Adsorption stage 3: Coating film 4: Clearance 5: Lip 6: Clasp 7: Push / pull bolt 8: Piping 9: Pump 10: Paint 11: Film 12: Doctor lip 13: Backup lip

Claims (10)

[Claims] 1. A curtain flow coater used for applying a paint on a flat plate, wherein an angle of at least one tip of a doctor lip portion and a backup lip portion of a die of the curtain flow coater is less than 90 degrees. Curtain flow coater characterized by 2. The curtain flow coater according to claim 1, wherein the angle of the tip of the doctor lip is less than 90 degrees, and the angle of the tip of the backup lip is 90 degrees. 3. The angle of the tip of the doctor lip is 30 to 30.
The curtain flow coater according to claim 1, wherein the curtain flow coater is 80 degrees. 4. A method of applying a coating material on a flat plate using a curtain flow coater, wherein the curtain flow coater according to any one of claims 1 to 4 is used as the curtain flow coater. Method. 5. A method of applying a coating material on a flat plate using a curtain flow coater, wherein the tip of at least one of a doctor lip portion and a backup lip portion of a die of the curtain flow coater is not parallel to the flat plate. A method of applying a paint characterized by: 6. The coating method according to claim 5, wherein the tip of the doctor lip is not parallel to the flat plate, and the tip of the backup lip is parallel to the flat plate. 7. The coating method according to any one of claims 4 to 7, wherein the coating material is a coating material for forming a coating film for a color filter. 8. A method for producing a coating film for a color filter, which comprises a step of applying a coating material for forming a coating film for a color filter onto a flat plate by using a curtain flow coater, wherein the curtain flow coater is any one of claims 1 to 4. A method for producing a coating film for a color filter, which comprises using the curtain flow coater described in 1. 9. A method for producing a coating film for a color filter, which comprises the step of applying a coating material for forming a coating film for a color filter onto a flat plate by using a curtain flow coater, and a doctor lip portion of a die of the curtain flow coater and a backup. A method for producing a coating film for a color filter, characterized in that at least one tip of the lip portion is applied in a state not parallel to the flat plate. 10. The coating film for a color filter according to claim 9, wherein a tip of the doctor lip portion is not parallel to the flat plate, and a tip of the backup lip portion is parallel to the flat plate. Manufacturing method.