JP2949816B2 - Manufacturing method of color filter - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of manufacturing a color filter used for colorizing a liquid crystal display.

[Prior Art] In recent years, demand for color filters has been increasing due to expansion of applications of liquid crystal displays. The color filter has a colored layer formed of a natural protein, an acrylic resin and a dye or a pigment, and on the colored layer,
An overcoat layer is provided by applying and curing a coating material for the purpose of improving reliability (heat resistance, moisture resistance, chemical resistance, etc.) and smoothing.

The properties required for the overcoat layer include: (1) transparency (2) adhesion to a color filter (3) heat resistance (250 ° C. or higher) depending on the manufacturing conditions of the liquid crystal display panel and required optical characteristics. (4) Chemical resistance (5) Adhesion with ITO (transparent electrode film) (6) Adhesion with sealing material.

[Problems to be solved by the invention]

As a coating material for forming a conventional overcoat layer, a thermosetting acrylic resin, a urethane resin,
There are epoxy-based resins and silica-based inorganic coating materials. However, conventional acrylic and urethane resins have heat resistance,
With low adhesion, epoxy (ITO)
There is a problem in that cracks are apt to occur after vapor deposition of (tin-oxide), and there is a problem that the silica-based coating material has low reliability such as low adhesion, and there is no coating material that can satisfy the above characteristics. Therefore, the reliability of a color filter using this as an overcoat layer was not sufficient.

An object of the present invention is to provide a method for manufacturing a color filter having an overcoat layer having good heat resistance, adhesion, and transparency.

[Means for solving the problem]

That is, the present invention relates to a method for producing a color filter having a colored layer on a transparent substrate and an overcoat layer provided on the colored layer, comprising a monomer having at least one epoxy group and an N- Coating comprising a copolymer comprising a monomer having either a substituted amide or an N-substituted imide group and at least one of a polycarboxylic acid and a polycarboxylic anhydride as a curing agent The object has been solved by forming an overcoat layer by applying a material on a colored layer and then curing by heating.

[Action]

In the method for producing a color filter of the present invention, a coating material in which any of an amide or imide group is introduced is applied to a part of the copolymer during the production process to form an overcoat layer. Not only does heat resistance improve than color filters with an overcoat layer formed by applying an acrylic resin, but also natural proteins of color filter materials,
Since it has high affinity with acrylic resins, dyes and pigments, it has excellent adhesion.

In addition, although the amide / imide group and the like are usually concerned about yellow coloring, they are not of a surprising degree.

[Detailed Description of the Invention]

The main component of the coating material used for forming the overcoat layer according to the color filter manufacturing method of the present invention has a monomer having at least one epoxy group and either an N-substituted amide or an N-substituted imide group. It is composed of a copolymer composed of a monomer and at least one of polycarboxylic acid and polycarboxylic anhydride as a curing agent.

Examples of the monomer having at least one epoxy group (hereinafter referred to as (a)) include glycidyl (meth) acrylate and 3,4 epoxybutyl (meth) acrylate. As the crosslinking component, a monomer having a hydroxyl group in addition to the epoxy group can be used, but an epoxy group is preferred because it has problems such as lower compatibility with an organic solvent and impairing smoothness.

Examples of the monomer having an N-substituted amide or N-substituted imide group (hereinafter referred to as (b)) include N, N-dimethyl (meth) acrylamide, (meth) acryloylmorpholine, N-phenylmaleimide, N-cyclohexyl And maleimide. Other amide group-containing monomers include acrylamide and the like. However, if they are not N-substituted, there is a problem that compatibility with an organic solvent is reduced and smoothness is impaired.

As for the ratio between (a) and (b), (a) is preferably 20 to 55 parts by weight. When (a) is 55 parts by weight or more, the adhesiveness is not improved, and when it is 20 parts by weight or less, crosslinking is insufficient and chemical resistance and hardness are reduced. The molecular weight of the copolymer is from 5,000 to 200,000, preferably from 10,000 to 50,000. If the molecular weight is 200,000 or more, crosslinking proceeds excessively, resulting in insufficient adhesion. If the molecular weight is less than 5,000, the crosslinking density is low and the resistance is impaired.

Further, the curing agent is a polyvalent carboxylic acid which reacts with an epoxy group, such as succinic acid, adipic acid, maleic acid, phthalic acid, isophthalic acid, terephthalic acid, hexahydrophthalic acid, etc., trimellitic acid, trimesic acid. And trifunctional carboxylic acids such as pyromellitic acid and 1,2,5,6-tetracarboxylnaphthalene. Among these, aromatic polycarboxylic acids having 3 to 4 functional groups and anhydrides thereof are preferable from the viewpoint of crosslink density and compatibility with the resin.

The amount of addition is in the range of 1 to 100 parts by weight, preferably 10 to 4 parts by weight, per 100 parts by weight of the copolymer of (a) and (b).
0 parts by weight. If the amount exceeds 100 parts by weight, the adhesiveness between the overcoat layer and the color filter will be reduced, and the stability of the coating material will be poor. If the amount is less than 1 part by weight, the crosslink density is not sufficiently increased, so that there is a problem in chemical resistance and toughness.

In addition to the components (a) to (c) described above, a Si coupling agent for further improving the adhesiveness can be added to the coating material, if necessary, such as methyltrimethoxysilane, vinyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and the like.

The coating material for forming the overcoat layer is obtained by uniformly mixing the above components. As a method of mixing these components, it is preferable to mix these components by dissolving them in an appropriate solvent.

Solvents that uniformly dissolve the coating material include ketones such as methyl isobutyl ketone, cyclohexanone, and isophorone, ethylene glycol dimethyl ether,
Diethylene glycol dimethyl ether, dioxane,
Ethers such as propylene glycol monomethyl ether and propylene glycol monoethyl ether; and esters such as butyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, and ethyl lactate. Particularly, ethylene glycol monoethyl ether acetate and diethylene glycol dimethyl ether are preferred from the viewpoint of solubility and coating properties.

The order of mixing the components of the coating material is not particularly limited. Also, the solution concentration of the coating material is not particularly limited, but is appropriately selected according to the purpose of use and the method of coating the transparent substrate. Generally 10 ~
Use at about 40% by weight.

The coating material obtained as described above is applied to a substrate having a transparent substrate 1 and a colored layer 2 or the like to a desired thickness by a roll coater, a spin coater or the like, as shown in FIG. By curing at 250 ° C. for about 30 minutes to 5 hours, the overcoat layer 3 is formed, and the color filter can be protected without impairing the color tone and transparency of the colored layer 2.

 Hereinafter, an embodiment of the present invention will be specifically described.

Example 1 50 g of phenylmaleimide, 50 g of glycidyl methacrylate, and 250 g of cyclohexanone were charged into a three-diameter round bottom flask equipped with a condenser, a stirrer, and a thermometer, and sufficiently purged with nitrogen, followed by azobisisobutyro. 1.5 g of nitrile was charged, the temperature of the solution was raised to 80 ° C., and stirring was continued for 5 hours to obtain a copolymer. The weight average molecular weight of this copolymer was 40,000 in terms of polystyrene.

25 g of a 12% diglyme solution of trimellitic acid was added to 100 g of the copolymer solution obtained here, and the mixture was stirred well to obtain a coating material.

After coating this coating material on the color layer of the color filter substrate produced earlier with a spin coater 1200 rpm, 2
Curing was performed at 00 ° C. for 60 minutes to obtain an overcoat layer. The obtained color filter was excellent in smoothness (0.2 μm or less) and had no abnormality in appearance. Results of contact thickness measurement 1.1
μm.

The following test was performed on the overcoat layer of the color filter manufactured as described above. First, the transmittance in the entire region of 400 to 700 nm was measured, and 95% or more was confirmed in the entire region. A microspectrophotometer manufactured by Olympus Corporation was used as a measuring instrument. Next, the adhesion between the overcoat layer and the color filter was examined. After 5 hours pressure cooker test at 120 ° C 2atm, cross cut test by tape peeling (JI
SK-5400), no peeling was observed. Further, an aqueous solution of _{5% NaOH, 5% H 2} SO 4, NMP (N- methylpyrrolidinone) in thickness after immersion room temperature for 30 minutes change of transmittance change, did not abnormality occurs for adhesion .

Furthermore, ITO (indium-
(Tin-oxide) was deposited to examine the suitability for ITO, but no abnormalities such as cracks and peeling were found. Good results were also obtained for the adhesiveness with the sealing agent.

From the above results, it was confirmed that the overcoat layer of the color filter obtained by the production method of the present invention was excellent in transparency, heat resistance, adhesiveness, ITO suitability, and the like.

Example 2 As in Example 1, GMA (glycidyl methacrylate) 60 g acryloyl morpholine 40 g ECA (ethylene glycol monoethyl ether acetate) 250 g AIBN (azobisisobutyronitrile) 1.2 g These were charged to obtain a copolymer. Was. The weight average molecular weight of this copolymer was 80,000 in terms of polystyrene.

After a coating material was obtained in the same manner as in Example 1, spin coating was performed on the color filter substrate in the same manner as in Example 1 to form an overcoat layer. The same test as in Example 1 was performed, and the results shown in Table 1 were obtained.

Example 3 As in Example 1, 50 g of GMA (glycidyl methacrylate) 50 g of cyclohexylmaleimide 50 g of ECA (ethylene glycol monoethyl ether acetate) 250 g 1 g of AIBN (azobisisobutyronitrile) 1 g These were charged to obtain a copolymer. . The weight average molecular weight of this copolymer was 40,000 in terms of polystyrene.

After a coating material was obtained in the same manner as in Example 1, spin coating was performed on the color filter substrate in the same manner as in Example 1 to form an overcoat layer. The same test as in Example 1 was performed, and the results shown in Table 1 were obtained.

[Comparative Example 1] GMA (glycidyl methacrylate) 100 g ECA (ethylene glycol monoethyl ether acetate) 250 g AIBN (azobisisobutyronitrile) 1 g In the same manner as in Example 1, a copolymer was prepared by charging them. The weight average molecular weight of this copolymer was 50,000 in terms of polystyrene.

After a coating material was obtained in the same manner as in Example 1, spin coating was performed on the color filter substrate in the same manner as in Example 1 to form an overcoat layer. The same test as in Example 1 was performed, and the results shown in Table 1 were obtained.

Comparative Example 2 GMA (glycidyl methacrylate) 85 g Phenylmaleimide 15 g Cyclohexanone 250 g AIBN (azobisisobutyronitrile) 1 g In the same manner as in Example 1, a copolymer was prepared by charging them. The weight average molecular weight of this copolymer was 60,000 in terms of polystyrene.

After a coating material was obtained in the same manner as in Example 1, spin coating was performed on the colored layer on the transparent substrate in the same manner as in Example 1 to form an overcoat layer. The same test as in Example 1 was performed, and the results shown in Table 1 were obtained.

[Effect of the Invention] Since the color filter manufactured by the manufacturing method of the present invention has any of the amide / imide groups in the coating material forming the overcoat layer, necessary physical properties,
The toughness, hardness, light resistance, transparency, solvent resistance, adhesion, and adhesion to the sealing material are extremely excellent in practical use.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a color filter. 1 transparent substrate 2 colored layer 3 overcoat layer 4 black matrix

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-298901 (JP, A) JP-A-62-163016 (JP, A) JP-A-61-45226 (JP, A) 35807 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) G02B 5/20 101 G02F 1/1335 505

Claims (1)

(57) [Claims] 1. A method for producing a color filter, comprising a colored layer on a transparent substrate and an overcoat layer provided on the colored layer, comprising: a monomer having at least one epoxy group; A copolymer comprising a monomer having either an amide or an N-substituted imide group and at least one of a polycarboxylic acid and a polycarboxylic anhydride;
A method for producing a color filter, comprising forming an overcoat layer by applying a coating material containing a seed as a main component on a coloring layer and then heating and curing the coating material.