JPH07168015A - Method for cleaning mouthpiece of curtain flow coated and manufacture of coating film for color filter - Google Patents

Abstract

PURPOSE:To easily clean paint off the end of the lip of a mouthpiece to prevent formation of stripes in the paint applied and uneven application of paint for enhanced quality and profitability by using a cleaning member whose surface is made from a high polymer resin to clean the lip of the mouthpiece. CONSTITUTION:A cleaning member 4 is used to clean the lip 10 of a mouthpiece 3 just before applying paint. Preferably, the upper part of the cleaning member 4, though not in a particular form, is shaped to fit the end of the lip 10, and the cleaning member 4 can be manufactured into a sheet-shaped member by cutting a sheet-shaped material into the proper shape. The surface of the cleaning member 4 is made from high polymer resin, which is not restricted to particular ones but is preferably one kind or a mixture of two or more kinds selected from Teflon resin, urethane resin, acrylic resin, polyester resin, polypropylene resin, fluororesin, polybutadiene resin, nitrile rubber, silicone rubber, and an ethylene vinyl acetate copolymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a lip portion 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. And a method for producing a coating film for a color filter using the same.

[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 paint supply path until it is discharged is sealed, so that no foreign matter is mixed in, and the change in the viscosity of the paint is small, so that the coating film thickness is uniform.

[0003]

However, a drawback of this coating method is that the paint after being discharged from the lip end of the mouthpiece tends to gradually adhere to the lip end. The adhered coating material is generated by evaporation of the solvent in the coating material to form a solid material, which forms vertical coating stripes in the coating direction on the coating film coated on the glass plate. Further, the solid matter is detached from the lip portion and brought into the applied coating film as a foreign matter. For the above reasons, cleaning of the lip end of the die is an essential issue in continuous production.

As a current method of cleaning the tip of the lip portion of the mouthpiece, there is a method of hand-wiping using a non-woven fabric impregnated with a solvent, or a method of cleaning the tip of the lip portion with a solvent. However, these methods have a problem that the substrate is contaminated by dust generated from the non-woven fabric, or the paint discharged from the lip portion of the die is contaminated, which causes vertical streaks in the coating film. On the other hand, the solvent cleaning method has a problem that the coating material attached to the lip portion of the die scatters together with the cleaning solvent and adheres to the coated substrate, resulting in contamination and uneven coating.

Therefore, the object of the present invention is to keep the characteristics of the conventional curtain flow coater such as the change in the viscosity of the paint being small and the coating film thickness being uniform, and the lip portion of the mouthpiece, which has been a problem to date. An object of the present invention is to provide a coating film for a color filter, which is free from coating streaks and coating unevenness and which is excellent in quality and economical efficiency by easily cleaning the paint attached to the tip.

[0006]

The present invention has the following configuration.

In a method for cleaning a die of a curtain flow coater used for applying a coating material on a flat plate, a curtain characterized in that a lip portion of the die is cleaned by using a cleaning member having a surface made of a polymer resin. How to clean the base of the flow coater.

In a method for producing a coating for a color filter, which comprises a step of coating a coating for forming a coating for a color filter on a flat plate and drying the coating, the lip portion of the die of the curtain flow coater is surfaced immediately before the coating. A method for producing a coating film for a color filter, which comprises cleaning with a cleaning member made of a polymer resin.

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

1 and 2 show coating by a curtain flow coater according to the present invention (slit die coater).
It is a schematic diagram showing an example. That is, FIG. 1 shows a state in which the cleaning member 4 is cleaning the lip portion 10 of the base 3 immediately before the coating material is applied. FIG. 2 shows a state in which the cleaning of the lip portion 10 of the mouthpiece 3 is completed and the application of the paint is started.

That is, the paint 9 is supplied from the pipe 7 into the base 3 by the pump 8. In this state, the base 3
The excess paint discharged from the tip of the lip portion 10 and attached to the surface of the lip portion 10 is cleaned by the cleaning device 5. Then, as the flat plate 1 is conveyed (in the direction of arrow A), the coating material is applied from the lip portion 10 of the die 3 onto the flat plate 1 which is suction-fixed on the suction stage 2 in a curtain state, and the coating film 11
Is formed. The uniformity of the coating film is determined by applying the curtain-shaped discharge paint to the gap between the lip portions 10 at the tip of the die and the flat plate 1.
It is controlled by adjusting the distance between the lip portion 10 and the lip portion 10.

The cleaning device 5 comprises a cleaning member 4 whose surface is made of polymer resin, a container 5 for holding the cleaning member 4, and a discharge pipe 6 for discharging the cleaned paint.
It is supported by. The cleaning procedure is as follows. First, the cleaning member 4 and the container 5 stop and rise just below the lip portion 10 of the base 3. By this operation, the upper portion of the cleaning member 4 comes into close contact with the lip portion 10 of the base 3. In this closely contacted state, the cleaning member 4 moves along the lip portion 10 to remove the paint adhering to the lip portion by scraping off or scraping it off, thereby completing the cleaning. After cleaning, the cleaning device 5 descends and the application is started. The unnecessary paint cleaned from the lip portion 10 by the cleaning member 4 collects in the container 5 and is discharged from the discharge pipe 6.

FIG. 3 shows an example of the cleaning member 4. The shape of the upper portion of the cleaning member 4 is not particularly limited, but it is preferably a shape that is in close contact with the tip of the lip portion 10.
The cleaning member 4 can be manufactured as a sheet-shaped member, for example, by cutting a sheet-shaped member into an appropriate shape, and the sheet thickness (width of the cleaning member) is
The range of 0.5 mm to 10 mm is preferable, and the range of 2 mm to 5 mm is more preferable. When the thickness is less than 0.5 mm, the elasticity of the sheet is poor and the cleaning effect is small. 10 mm
If the thickness is exceeded, the paint scraped from the tip of the lip may be accumulated between the sheet-shaped cleaning member and the tip of the lip, which may cause contamination. As the cleaning member 4, two or more such sheet-like members are arranged with an interval (about 1 mm to 10 mm) such that the paint scraped from the lip portion easily flows into the container 5. Those that are present are preferably used. This is because the cleaning effect increases as the number of arranged sheets increases. However, since the width of the curtain flow coater is limited and the cleaning member slides from one end of the curtain flow coater to the other, the number of sheets is automatically determined by determining the width and spacing of the sheet-shaped members. To be done. For example, the width of the curtain flow coater is 300
mm, the width of the sheet-shaped member is 5 mm, and the interval is 2 mm, the number of sheets is appropriately about 2 to 7. FIG. 3 shows an example in which three sheets are arranged.

The surface of the cleaning member 4 is made of a polymer resin, and the polymer resin is not particularly limited, but Teflon resin, urethane resin, acrylic resin,
Polyester resin, polypropylene resin, fluororesin,
Polybutadiene resin, nitrile rubber, silicone rubber,
One type or a mixture of two or more types such as ethylene / vinyl acetate copolymer is preferably used. Among these, those having rubber elasticity are preferable for good adhesion to the tip of the lip portion, and those having large resistance to the solvent (N-methyl-2-pyrrolidone etc.) contained in the paint are preferable, and Those having durability are preferable. From the above points, silicone rubber is most preferable. The part other than the surface may be made of the same polymer resin as the surface, or may be made of a completely different material.

It is also preferable to mix conductive powder in order to remove static electricity generated in the resin constituting the surface of these cleaning members and prevent dust from adhering.
The conductive powder is not particularly limited,
A powder which itself has excellent conductivity is preferably used. As such a conductive powder, one kind or a mixture of two or more kinds of conductive carbon, platinum, gold, nickel, silver, copper, cobalt, tin, aluminum and palladium is preferably used. These conductive powders may be mixed in the resin in an amount of about 40% to 100% by weight. If the amount of the conductive powder is too large, the resin becomes brittle and the durability becomes poor.

The cleaning by the cleaning member is most effective if it is carried out immediately before the coating of the paint, since most of the paint attached to the lip portion of the mouthpiece is removed, but the present invention is not limited to this.
It can be performed appropriately.

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

The case where the cleaning 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 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 and the like, and photosensitive resins thereof and the like are 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 paint is preferably in the range of 50 ° C to 160 ° C, more preferably in the range of 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 colorant-free paint may be applied to the red, green and blue fine patterns to form a protective film and a colorant-containing paint for the purpose of improving smoothness.

The method for cleaning 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.

[0028]

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

Example 1 and Comparative Example 1 A coating material was applied onto a glass substrate using the coating apparatus shown in FIGS. 1 and 2. The glass substrate is 300m in size
The tip of the lip portion 10 of the mouthpiece 3 was cleaned by using the cleaning member 4 immediately before the application, using an m × 350 mm, 1.1 mm thick one. Then, N-methyl-2-pyrrolidone solvent, chlorobrominated phthalcyanine green (CI Pigment Green 36) and disazo yellow HR (C.I.
I. Pigment Yellow 83) A polyamic acid coating containing a pigment added and dispersed was applied at a rate of 2 m / min at a solid content of 8 wt% and a viscosity of 100 cp, and dried at 120 ° C. for 10 minutes. As the cleaning member 4, a 5 mm-thick silicone rubber sheet (manufactured by Tigers Polymer Co., Ltd.) is formed in a shape in which the upper surface is in close contact with the lip tip of the die, and the pitch is 3 mm.
The sheets were arranged and used (Example 1).

As a result of continuous coating on 100 glass substrates by the above method, the coating material was very little adhered to the tip of the lip portion after cleaning, and any of the coating substrates obtained had vertical stripes, unevenness, and A good coating film was obtained without contamination by dust or the like.

On the other hand, coating was performed in the same manner as in Example 1 without using the cleaning member of the present invention (Comparative Example 1). First
In the table, the results of visual evaluation of the appearance of the coating films of the coated substrate obtained in Example 1 and the coated substrate obtained in Comparative Example 1 are shown in comparison.

[0032]

[Table 1] In Comparative Example 1, as the number of coatings increases, the lip tip portion of the die becomes soiled with the adhered paint. As a result, the generation of vertical stripes, the occurrence of coating unevenness, and the amount of foreign matter caused by the coating material 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.

Example 2 Three Teflon sheets each having a thickness of 3 mm were used as a cleaning member for the spinneret and coated in the same manner as in Example 1. The paint used was ethyl cellosolve acetate solvent and dianthraquinone nil red (CI Pigment Red 177).
An acrylic resin (Cotax, manufactured by Toray) in which a pigment is added and dispersed is used, and this coating material has a solid content of 20 wt% and a viscosity of 25.
It was applied in the state of cp and dried at 130 ° C. for 15 minutes. As a result, as in Example 1, a good coating film was obtained without generation of vertical stripes, coating unevenness, foreign matter due to pigment, and the like.

Example 3 Silicone "SE6720" (Toray Dow Corning
Silicone Co., Ltd.) and 70% by weight of conductive carbon “Denka Black” (manufactured by Denki Kagaku Kogyo Co., Ltd.) with respect to the silicone were mixed and uniformly dispersed with a kneader. A sheet having a thickness of 3 mm is formed using this dispersion liquid,
C., 30 minutes, and then 200.degree. C. for 1 hour to obtain a silicone rubber sheet having a high tear strength.

As the mouthpiece cleaning member, three silicone rubber sheets containing the above-mentioned conductive carbon were used and coated in the same manner as in Example 1. As a result, as compared with Example 1, almost no dust adhered to the lip portion, and as a result,
A better coating film was obtained without generation of vertical stripes, coating unevenness, foreign matter due to pigment, and the like.

[0036]

According to the present invention, it becomes possible to easily clean the excess paint attached to the lip portion which is the tip of the die of the curtain flow coater. Therefore, the coating film on the flat plate is free from vertical appearance of streaks, coating unevenness, stains due to pigments, stains due to the die cleaning member, and the like, and the productivity is remarkably improved.

By using silicone rubber as the polymer resin on the surface of the cleaning member, it becomes possible to adhere well to the tip of the lip portion, and it is also resistant to solvents such as N-methyl-2-pyrrolidone. Since it is also durable, the cleaning effect can be further enhanced.

Further, by performing the cleaning just before applying the paint, most of the paint adhering to the lip portion of the mouthpiece is removed, so that it is possible to effectively prevent coating stripes, coating unevenness, and contamination due to the pigment. .

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

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

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of coating (slit die coater) by a curtain flow coater according to the present invention,
It shows a state in which the lip portion of the mouthpiece is being cleaned by the cleaning member immediately before applying the paint.

FIG. 2 is a schematic view showing an example of coating (slit die coater) by a curtain flow coater according to the present invention,
It shows a state in which the cleaning of the lip portion of the mouthpiece is completed and the application of the paint is started.

FIG. 3 is a schematic view showing an example of a cleaning member for cleaning a lip portion of a die of a curtain flow coater.

[Explanation of symbols]

 1: Flat plate 2: Adsorption stage 3: Dipstick 4: Cleaning member 5: Container 6: Paint discharge pipe 7: Paint supply pipe 8: Pump 9: Paint 10: Lip part 11: Coating film 12: Support

Claims (6)

[Claims] 1. A method for cleaning a die of a curtain flow coater used for applying a coating material on a flat plate, wherein a lip portion of the die is cleaned by using a cleaning member whose surface is made of a polymer resin. How to clean the base of the curtain flow coater. 2. The method for cleaning a die of a curtain flow coater according to claim 1, wherein the polymer resin is silicone rubber. 3. The method for cleaning a curtain flow coater according to claim 1, wherein the lip portion of the die of the curtain flow coater is cleaned immediately before the coating of the paint on the flat plate with the curtain flow coater. 4. The method for cleaning a 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 color filter coating film, which comprises the steps of applying a coating material for forming a color filter coating film onto a flat plate and drying the coating material, and immediately before applying the coating material, the lip portion of the die of the curtain flow coater. A method for producing a coating film for a color filter, characterized in that the surface is cleaned using a cleaning member having a surface made of a polymer resin. 6. The method for producing a coating film for a color filter according to claim 5, wherein the polymer resin is silicone rubber.