JP3306838B2 - CLEANING METHOD FOR CURTAIN FLOW COATER AND METHOD FOR PRODUCING COATING FILM FOR COLOR FILTER - Google Patents

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 mouthpiece of a curtain flow coater, which is particularly preferably used when a color filter coating film used for a color display or a solid-state image sensor using liquid crystal is applied. And a method for producing a coating film for a color filter using the same.

[0002]

2. Description of the Related Art In general, a color filter used for a display using a liquid crystal or the like is arranged on a transparent substrate such as a glass plate while maintaining a certain positional relationship between three primary color patterns of red, green and blue. I have. A curtain flow coater is one of the methods for coating a thin film on a glass substrate or the like. This coating method is disclosed in, for example, Japanese Patent Application Laid-Open No. 5-1105, in which a paint is discharged in a curtain shape from the tip of a lip portion of a die called a slit die, a die head, or a T die, and is applied to a substrate in a non-contact manner. belongs to. This method is characterized in that the paint supply path until the ink is discharged is sealed, so that no foreign matter is mixed in, and the viscosity of the paint is small, so that the applied film thickness is uniform.

[0003]

However, a drawback of this coating method is that the paint discharged from the tip of the lip of the base is likely to gradually adhere to the tip of the lip. The attached paint becomes a solid by evaporating the solvent in the paint, and is generated as a vertical coating streak in the coating direction on the coating film applied on the glass plate. Further, the solids are detached from the lip portion and are carried as foreign matter into the applied coating film. For the above reasons, cleaning the tip of the lip of the base is an indispensable task in continuous production.

[0004] Current methods for cleaning the tip of the base lip include hand wiping using a non-woven fabric impregnated with a solvent or cleaning the tip of the lip with a solvent. However, these methods have problems that the substrate is contaminated by dust generated from the nonwoven fabric, and that the paint discharged from the lip portion of the base is contaminated and causes vertical streaks of the coating film. On the other hand, in the solvent cleaning method, there is a problem that the paint adhered to the lip portion of the base scatters together with the cleaning solvent and adheres to the application substrate, causing contamination and application unevenness.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a conventional lip portion of a mouthpiece which retains the characteristics of a conventional curtain flow coater such as a small change in paint viscosity and a uniform coating film thickness. An object of the present invention is to provide a color filter coating film which is easy to clean the paint adhering to the tip, has no coating streaks and coating unevenness, and is excellent in quality and economy.

[0006]

The present invention has the following configuration.

In a method of cleaning a mouthpiece of a curtain flow coater used when applying paint on a flat plate of a sheet, the upper surface is in close contact with the lip end of the mouthpiece immediately before applying the paint. A cleaning member made of a polymer resin in the form of a sheet having a thickness of 0.5 to 10 mm and having a rubber elasticity and having a surface having rubber elasticity is brought into close contact with the cleaning member, and is moved along the lip portion to remove the applied paint. A method for cleaning a mouthpiece of a curtain flow coater, which comprises cleaning by scraping off.

In a method for producing a coating film for a color filter, comprising a step of applying a coating material for forming a coating film for a color filter on a flat plate using a curtain flow coater and drying the coating material, the coating film is applied immediately before applying the coating material. The upper surface of the lip of the base of the flow coater is formed in a shape to be in close contact with the tip of the lip of the base, and the surface has a rubber elasticity thickness of 0.5.
A method for producing a coating film for a color filter, comprising: bringing a cleaning member made of a polymer resin in the form of a sheet having a size of 10 mm into close contact, moving along the lip portion, and scraping off the adhered paint to clean.

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

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

That is, the paint 9 is supplied from the pipe 7 into the base 3 by the pump 8. In this state, cap 3
The excess paint discharged from the tip of the lip 10 and adhered to the surface of the lip 10 is cleaned by the cleaning device 5. Then, in accordance with the transport of the flat plate 1 (in the direction of arrow A), the paint is applied from the lip portion 10 of the base 3 to the flat plate 1 that is suction-fixed onto the suction stage 2 in a curtain state.
Is formed. The uniformity of the coating film is determined by applying the paint discharged in a curtain shape to the gap between the lip portions 10 at the tip of the base and the flat plate 1.
And the lip portion 10 is adjusted to control the distance.

The cleaning device 5 comprises a cleaning member 4 having a surface made of a polymer resin, a container 5 for holding the cleaning member 4, and a discharge pipe 6 for discharging the cleaned paint.
Supported by The cleaning procedure is as follows. First, the cleaning member 4 and the container 5 stop immediately below the lip 10 of the base 3 and rise. With this operation, the upper portion of the cleaning member 4 comes into close contact with the lip portion 10 of the base 3. The cleaning member 4 moves along the lip portion 10 in the closely contacted state, and removes the paint adhered to the lip portion by scraping or scraping off the paint, thereby completing the cleaning. After cleaning, the cleaning device 5 descends to start coating. The unnecessary paint cleaned from the lip portion 10 by the cleaning member 4 accumulates 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 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-like member, for example, by cutting a sheet-like member into an appropriate shape. The thickness of the sheet (the width of the cleaning member) is as follows.
The range is preferably from 0.5 mm to 10 mm, more preferably from 2 mm to 5 mm. When the thickness is less than 0.5 mm, the elasticity of the sheet is poor and the cleaning effect is small. 10mm
If the thickness is larger, the paint scraped off from the tip of the lip accumulates between the sheet-like cleaning member and the tip of the lip, and tends to cause contamination. Further, as the cleaning member 4, two or more sheets of such a sheet-like member are arranged at intervals (about 1 mm to 10 mm) at which the paint scraped from the lip portion easily flows into the container 5. Are preferably used. This is because the greater the number of sheets arranged, the greater the cleaning effect. 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 end, if the width and the interval of the sheet-like members are determined, the number of sheets is naturally determined. Is done. For example, if the width of the curtain flow coater is 300
mm, the width of the sheet-like 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. The polymer resin is not particularly limited, but may be a Teflon resin, a urethane resin, an acrylic resin, or the like.
Polyester resin, polypropylene resin, fluororesin,
Polybutadiene resin, nitrile rubber, silicone rubber,
One or a mixture of two or more such as ethylene / vinyl acetate copolymers is preferably used. Among these, those having rubber elasticity are preferable in order to make good contact with the tip of the lip portion, and those having high resistance to a solvent (such as N-methyl-2-pyrrolidone) contained in the coating material are preferable. Those having durability are preferred. In view of the above, silicone rubber is most preferred. The portion 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 a 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 that is itself a powder having excellent conductivity is preferably used. As such a conductive powder, one or a mixture of two or more of conductive carbon, platinum, gold, nickel, silver, copper, cobalt, tin, aluminum and palladium is suitably used. These conductive powders may be mixed at about 40% by weight to 100% by weight with respect to the resin. If the amount of the conductive powder is too large, the resin becomes brittle, resulting in poor durability.

If the cleaning by the cleaning member is performed immediately before the application of the paint, the paint attached to the base lip is almost removed, which is most effective. However, the present invention is not limited to this.
It can be performed as appropriate.

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

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

Hereinafter, the case where the cleaning method of the present invention is applied to the formation of a color filter coating film will be described.

In the case of forming a coating film for a color filter, a transparent flat plate is used as the flat plate. 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 such as polycarbonate and polymethyl methacrylate, a plastic film and a glass plate is preferably used. Among these, a glass plate is more preferably used.

The kind of the 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 a photosensitive resin thereof are used. It is preferably used. In addition, a coloring agent such as a dye or a pigment may be dispersed and mixed in these resins.

The thickness of the film after coating on the transparent flat plate is not particularly limited, but is 0.1 μm to 5 μm
m is preferable, and more preferably 0.2 μm to 3 μm.
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 problem in quality. On the other hand, when the thickness exceeds 5 μm, the amount of the paint used increases, and the economy is low.

The method for producing a color filter includes, for example, the following methods, but is not limited thereto. First, a light shielding layer composed of a fine pattern is formed on a transparent flat plate. A thermosetting paint to which a coloring agent is added is applied on the light-shielding layer, and dried at a temperature of 50C to 150C 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 positive photoresist is developed and etched to form a relief pattern. The thermosetting coating film is etched using the relief pattern as a mask. Subsequently, after the positive photoresist is removed, the coating is thermally cured 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 color filters.

[0024] 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 is long and the production efficiency is poor. On the other hand, when the temperature exceeds 160 ° C., the thermosetting proceeds and becomes insoluble in the developer.

On the other hand, in the case of a photosensitive paint to which a colorant is added, a light-shielding layer composed of a fine pattern is formed on a transparent flat plate, and the photosensitive paint to which a colorant is added is applied on the light-shielding layer. 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, and the photosensitive coating film is photo-cured. Thereafter, 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 color filters.

If necessary, a color filter may be formed by applying a colorant-free paint on the red, green and blue fine patterns for the purpose of improving the protective film and smoothness.

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

[0028]

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

Example 1, Comparative Example 1 A coating material was applied onto a glass substrate using the coating apparatus shown in FIGS. The glass substrate is 300m in size
The tip of the lip portion 10 of the base 3 was cleaned with the cleaning member 4 immediately before application using a material having a size of mx 350 mm and a thickness of 1.1 mm. Thereafter, an N-methyl-2-pyrrolidone solvent, chlorobrominated phthalocyanine green (CI pigment green 36) and disazo yellow HR (C.I.
I. Pigment Yellow 83) A polyamic acid paint to which a pigment was 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 such that the upper surface is in close contact with the lip tip of the base, and the pitch is 10 mm.
The sheets were arranged and used (Example 1).

As a result of continuous application to 100 glass substrates by the above-mentioned method, the adhesion of the paint to the tip of the lip after cleaning is extremely small, and any of the obtained applied substrates has vertical stripes, unevenness and unevenness. A good coating film was obtained without contamination by dust and 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 coating films of the coated substrate obtained in Example 1 and the coated substrate obtained in Comparative Example 1 are shown.

[0032]

[Table 1] In Comparative Example 1, as the number of coatings increases, the tip of the lip of the die becomes stained with the applied paint. As a result, the occurrence of vertical streaks, the occurrence of coating unevenness, and the increase in foreign matters caused by paint 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.

[0033]

Example 2 Silicone "SE6720" (Dow Corning Toray)
Silicone Co., Ltd.) and 70% by weight of conductive silicone "Denka Black" (manufactured by Denki Kagaku Kogyo Co., Ltd.) based on the silicone were mixed and uniformly dispersed by a kneader. A 3 mm-thick sheet is formed using this dispersion,
C. for 30 minutes and then at 200.degree. C. for 1 hour to produce a silicone rubber sheet having a strong tear strength.

The same method as in Example 1 was applied using three silicone rubber sheets containing conductive carbon as the base cleaning member. As a result, compared to the first embodiment, there is almost no dust attached to the lip portion.
A better coating film was obtained without generation of vertical stripes, coating unevenness, and foreign matters caused by pigments.

[0036]

According to the present invention, it is possible to easily clean excess paint adhering to the lip, which is the tip of the mouthpiece of the curtain flow coater. For this reason, appearance defects such as vertical coating streaks, coating unevenness, contamination due to the pigment, and contamination by the base cleaning member do not occur on the coating film on the flat plate, and productivity can be significantly improved.

By using silicone rubber as the polymer resin on the surface of the cleaning member, it is possible to make good contact with the tip of the lip, and it is resistant to solvents such as N-methyl-2-pyrrolidone. Yes, it is more durable, so the cleaning effect can be further enhanced.

Further, by performing the cleaning immediately before the application of the paint, most of the paint adhered to the base lip portion is removed, so that coating streaks, coating unevenness, and contamination caused by the pigment can be effectively prevented. .

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

Therefore, it is possible to continuously produce a high-quality color filter which is inexpensive and economical.

[Brief description of the 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;
This shows a state in which the lip portion of the base is being cleaned by the cleaning member immediately before the application of 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;
This shows a state in which cleaning of the lip portion of the base has been completed and application of paint has started.

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

[Explanation of symbols]

 1: flat plate 2: suction stage 3: base 4: cleaning member 5: container 6: paint discharge pipe 7: paint supply pipe 8: pump 9: paint 10: lip portion 11: coating film 12: support

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Claims (5)

(57) [Claims] 1. A method of cleaning a mouthpiece of a curtain flow coater used when applying paint on a flat plate of a single sheet, wherein immediately before the paint is applied, the lip portion of the mouthpiece has an upper surface with a lip tip of the mouthpiece. A cleaning member made of a sheet-like polymer resin having a thickness of 0.5 to 10 mm and having a rubber elasticity and having a surface elastically adhered thereto, moved along the lip portion, and adhered. A method for cleaning a mouthpiece of a curtain flow coater, which comprises cleaning by scraping off paint. 2. The method for cleaning a mouthpiece of a curtain flow coater according to claim 1, wherein the polymer resin is silicone rubber. 3. The method for cleaning a mouthpiece of a curtain flow coater according to claim 1, wherein the paint is a paint for forming a coating film for a color filter. 4. 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 on a single sheet flat plate using a curtain flow coater and drying the coating film, immediately before applying the coating material. The curtain flow coater has a lip portion of a base having an upper surface formed to be in close contact with a lip tip of the base and having a surface having a rubber elasticity of 0.5 in thickness.
A method for producing a coating film for a color filter, comprising: bringing a cleaning member made of a polymer resin in the form of a sheet having a size of 10 mm into close contact, moving along the lip portion, and scraping off the adhered paint to clean. 5. The method according to claim 4, wherein the polymer resin is silicone rubber.