JP2011068901A - Thermosetting resin composition for transparent protective film, transparent protective film, and color filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermosetting resin composition which can form a transparent protective film having excellent adhesion, high hardness, and high transparency; to provide a transparent protective film obtained by applying the thermosetting resin composition to form a film and thermally curing it; and to provide a color filter including the transparent protective film. <P>SOLUTION: The thermosetting resin composition for a transparent protective film includes (1) at least one or more kinds of reactive groups selected from a hydroxy group and a carboxy group, (2) epoxy, and (3) an acrylic copolymer having an ethylenic double bond, and a solvent as main components. The hydroxy group or carboxy group which is included in the thermosetting resin composition exhibits adhesion to a substrate such as a glass substrate. The ethylenic double bond undergoes a cleavage and polymerization reaction during thermal curing and therefore improves the crosslinking density in the film. The thermosetting resin composition for a transparent protective film can be stored in a stable state with time although it has one or more reactive groups selected from a hydroxy group and a carboxy group, and epoxy. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a thermosetting resin composition suitable for a transparent protective film for a color filter, a transparent protective film formed using the thermosetting resin composition, and a color filter. The present invention relates to a thermosetting resin composition suitable for a transparent protective film for a color filter that enables a high color liquid crystal display device, and a color filter having a transparent protective film formed using the thermosetting resin composition.

  In recent years, color liquid crystal display devices have attracted attention as flat displays. In general, a color liquid crystal display device has a structure in which a color filter and a counter electrode substrate are opposed to each other, and a liquid crystal layer is formed in a gap portion (1 to 10 μm). The color filter is colored by a black matrix and pixels of a plurality of colors (usually, three primary colors of red (R), latitude (G), and blue (B) or three primary colors of yellow, magenta, and cyan) on a transparent substrate. A layer or, recently, a color hologram is provided, and a transparent protective film and a transparent electrode are sequentially laminated thereon. And it is comprised so that a color image may be obtained by controlling the light transmittance of the liquid crystal layer of the part corresponding to each pixel and color hologram of the colored layers R, G, and B of each color.

  The transparent protective film in such a color filter has a function of passivation that prevents ionic substances from being emitted from the color filter, a function of forming a protective film having adhesion and strength to protect pixels, It plays the role of flattening gap unevenness due to waviness of the transparent substrate surface of the filter, gap unevenness between R, G, and B pixels, or gap unevenness within each of R, G, and B pixels. Further, the transparent protective film in the color filter needs to have high transparency in order to transmit light.

  The present invention provides a thermosetting resin composition capable of forming a transparent protective film having excellent adhesion, high hardness, and high transparency, and coating the thermosetting resin composition to form a film. Then, it aims at providing the transparent protective film formed by thermosetting, and providing the color filter which has this transparent protective film.

  In order to solve the above-described problems, the thermosetting resin composition for a transparent protective film of the present invention comprises (1) one or more reactive groups selected from a hydroxyl group and a carboxyl group, (2) an epoxy, and (3 ) An acrylic copolymer having an ethylenic double bond and a solvent as a main component.

  The thermosetting resin composition for a transparent protective film of the present invention should be stored in a stable state over time despite having one or more reactive groups selected from a hydroxyl group and a carboxyl group, and an epoxy. In addition, the protective film using the thermosetting resin composition has high transparency, high hardness, high density, and good substrate adhesion. In particular, it is suitable for use as a protective film for color filters such as LCD.

  Since the thermosetting resin composition for a transparent protective film of the present invention has a hydroxyl group or a carboxyl group, the substrate adhesion to a glass substrate or the like is excellent.

It is a schematic block diagram which shows an example of the color filter of this invention.

DESCRIPTION OF SYMBOLS 1 Color filter 2 Transparent substrate 3 Colored layer 3R Red pattern 3G Green pattern 3B Blue pattern 4 Black matrix 5 Transparent protective film 6 Transparent electrode

  The hydroxyl group or carboxyl group contained in the thermosetting resin composition of the present invention can exert substrate adhesion to a glass substrate or the like.

  The epoxy contained in the thermosetting resin composition of the present invention is preferably one or more selected from cyclic ethers and alicyclic epoxies, and these epoxies are thermosetting resins having a bulky skeleton structure. Therefore, the obtained transparent protective film has high hardness. The cyclic ether is selected from one or more of oxetane acrylate [compound name: (3-methyl-3-oxetanyl) methyl acrylate] and oxetane methacrylate [compound name: (3-methyl-3-oxetanyl) methyl methacrylate]. Can do.

  In addition, the ethylenic double bond is cleaved and polymerized during thermosetting to improve the crosslink density in the film.

  The thermosetting resin composition of the present invention is a compound having the reactive groups or chemical structures of (1) and (2) above, or the reactive groups or chemical structures of (1), (2) and (3) above. Can be mixed and copolymerized to obtain an acrylic copolymer, and a solvent can be further mixed and diluted to adjust to a desired viscosity.

  As the solvent that can be used in the thermosetting resin composition of the present invention, a solvent having a solubility of 20 parts by weight or less with respect to 100 parts by weight of water has no hygroscopic property, and the reaction between epoxy and water can be suppressed. The curable resin composition is preferably used because it keeps stable over time. Examples of such water-soluble solvents include: 3-methoxybutyl acetate, propylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 3-methoxy-3-methyl-1-butyl acetate, propylene glycol monomethyl ether acetate And ethylene glycol monobutyl ether acetate.

  The amount of the solvent used is preferably adjusted so that the viscosity of the thermosetting resin composition is 1 cps to 100 cps in consideration of coating workability. It is particularly preferable to adjust so as to be 1 cps to 10 cps.

  Next, the color filter and transparent protective film of the present invention will be described.

  FIG. 1 is a schematic configuration diagram illustrating an example of a color filter of the present invention. In FIG. 1, a color filter 1 of the present invention includes a colored layer 3 and a black layer formed in a predetermined pattern using pixels made of red, green and blue, or pixels made of yellow, magenta and cyan on a transparent substrate 2. A transparent protective film 5 formed so as to cover the matrix 4 and the colored layer 3 is provided, and a transparent electrode 6 for driving liquid crystal is formed on the transparent protective film 5.

  As the transparent substrate 2 constituting such a color filter 1, flexible materials such as quartz glass, pyrex glass, synthetic quartz plate, or inflexible rigid materials, or transparent resin films, optical resin plates, etc. are used. The flexible material which it has can be used. Among them, Corning 7059 glass is a material having a small coefficient of thermal expansion, excellent dimensional stability and workability in high-temperature heat treatment, and is a non-alkali glass that does not contain an alkali component in the glass. Suitable for color filters used in display devices.

  The colored layer 3 constituting the color filter 1 has a red pattern 3R, a green pattern 3G, and a blue pattern 3B arranged in a desired form such as a mosaic type, a stripe type, a triangle type, or a four-pixel arrangement type. It is provided in a predetermined area between the colored patterns and outside the colored layer 3 forming area.

  The coloring layer 3 is a dyeing method in which a dyed base material is applied, and a pattern formed by exposure and development through a photomask is dyed. A coloring pigment is dispersed in advance in a photosensitive resist, and then a photomask is used. A pigment dispersion method for exposure and development, a printing method for printing each color with printing ink, a transparent conductive layer is formed in advance on a transparent substrate, a positive resist layer is formed on the transparent conductive layer, and exposure / After developing and exposing a predetermined portion of the transparent conductive layer, any of the electrodeposition methods, such as forming a colored layer by applying current to the transparent conductive layer while the transparent substrate is immersed in the electrodeposition liquid You may form using a method.

  The black matrix can also be formed by any of the above dyeing method, pigment dispersion method, printing method, and electrodeposition method, or may be formed by chromium vapor deposition or the like.

  The transparent protective film is prepared by subjecting the above-described thermosetting resin composition of the present invention to a dry film thickness of 0.00 by a method such as spin coater, roll coater, spray, or printing on a transparent substrate on which a colored layer and a black matrix are formed. It is formed by coating at 5 to 20 μm, preferably 1 to 8 μm, and then heated. When using a spin coater, the number of rotations is preferably set within a range of 500 to 1500 times / minute.

  In the formation of the transparent protective film of the present invention, the epoxy present in the acrylic copolymer in the thermosetting resin composition, in particular, the cyclic ether and the alicyclic epoxy, and the hydroxyl group present in the acrylic copolymer and Curing is carried out by reaction with one or more reactive groups selected from carboxyl groups by heat.

  Moreover, you may add a silane coupling agent to the thermosetting resin composition of this invention for the purpose of the adhesive improvement of a color filter layer and substrate glass as needed.

  Moreover, in order to improve the leveling property at the time of coating, you may add surfactant.

  The heat treatment for the coating film of the thermosetting resin composition can be usually performed under conditions of 100 to 250 ° C. and about 5 to 90 minutes. By this heat treatment, the epoxy contained in the thermosetting resin composition reacts with a hydroxyl group and / or a carboxyl group to cure the coating film to form a transparent protective film. Further, at this time, the ethylenic double bond is cleaved and polymerized to have an effect of increasing the crosslinking density.

  The transparent electrode on the transparent protective film is made of a general method such as a sputtering method, a vacuum deposition method, a CVD method, etc. using indium tin oxide (ITO), zinc oxide (ZnO), tin oxide (SnO), or an alloy thereof. It is formed by a film forming method, and is formed into a predetermined pattern by etching using a photoresist as necessary. The thickness of the transparent electrode is about 20 to 500 nm, preferably about 100 to 300 nm.

Hereinafter, the present invention will be described in detail by way of examples.
(Synthesis of copolymer resin (1))
composition:
・ Methyl methacrylate… 60.3mol%
・ 2-hydroxyethyl methacrylate: 14.3 mol%
・ Methacrylic acid: 5.4 mol%
・ Glycidyl methacrylate: 6.5 mol%
・ (Meth) acryloyl alkyl isocyanate: 13.5 mol%
Were mixed to obtain an acrylic copolymer having an oxidation of 26.5 mgKOH / g and a molecular weight of 14,000 (in terms of polystyrene).

(Synthesis of copolymer resin (2))
composition:
・ Methyl methacrylate… 61.2mol%
・ 2-hydroxyethyl methacrylate: 14.5 mol%
・ Methacrylic acid: 5.5 mol%
-Oxetane methacrylate (OXE-30: trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd.) 5.1 mol%
・ (Meth) acryloylalkyl isocyanate: 13.7 mol%
Were mixed to obtain an acrylic copolymer having an oxidation of 23.2 mgKOH / g and a molecular weight of 9300 (polystyrene conversion).

(Synthesis of copolymer resin (3))
composition:
・ Methyl methacrylate: 61.4 mol%
・ 2-hydroxyethyl methacrylate: 14.5 mol%
・ Methacrylic acid: 5.5 mol%
-Alicyclic epoxy (meth) acrylic monomer (Cyclomer M100: trade name, manufactured by Daicel Chemical Industries, Ltd.) ... 4.8 mol%
・ (Meth) acryloylalkyl isocyanate: 13.8 mol%
Were mixed to obtain an acrylic copolymer having an oxidation of 30.0 mgKOH / g and a molecular weight of 21000 (polystyrene conversion).

(Comparative resin)
・ Orthocresol novolac type epoxy resin (Epicoat 180S65: trade name, manufactured by Yuka Shell Epoxy Co., Ltd.)
When used to dilute each of the above resins, a solvent having the property of keeping the resin stable over time was next examined. For each solvent listed in Table 1 below, the solubility of each solvent in 100 parts by weight of water is shown in Table 1 below. Further, the time-dependent stability of each resin when the above resins are diluted with the respective solvents listed in Table 1 below is examined, and the results are shown in Table 1 below. Dilution was performed at a solid content concentration of 40 parts by weight. After dilution, the viscosity was measured with a B-type viscometer, stored in a sealed container at room temperature in a dark place for 30 days, and then the viscosity was measured with a B-type viscometer. In the evaluation of the stability with time of the resin by each solvent type, the viscosity increase was less than 10%, and the viscosity increase was 10% or more.

  The copolymer resins (1) to (3) and the comparative resin are each diluted with 3-methoxybutyl acetate to a viscosity of about 6 cps, spin-coated on a well-washed glass substrate and color filter, and dried sufficiently, and then hot plate Then, pre-baking was performed at 80 ° C. for 5 minutes, and then final curing was performed at 230 ° C. for 30 minutes in a clean oven to form a transparent protective film. The film thickness of the transparent protective film after final curing was about 1.5 μm. The transparent protective film thus obtained was measured for temperature-resistant pure water resistance, solvent resistance, heat resistance, visible light transmittance (400 nm to 700 nm), visible light transmittance after 1 hour at 250 ° C., and pencil hardness. It shows in Table 2. Moreover, each evaluation method is shown below.

Cross cut tape peeling test: After forming cross cut scratches with a cutter according to JISK5400 (1900) 8.5, and sticking the adhesive tape on the scratches, the adhesive tape was peeled off and evaluated by the shape of the scratches.
Thermal pure water resistance: After immersion in pure water at 80 ° C. for 1 hour, a cross-cut tape peeling test was conducted for evaluation.
Solvent resistance: After immersion in N-methylpyrrolidone at 40 ° C. for 1 hour, evaluation was performed by a cross-cut tape peeling test.
Heat resistance: After standing in a clean oven at 250 ° C. for 1 hour, a cross-cut tape peeling test was performed for evaluation.
Visible light transmittance after 1 hour at 250 ° C .: For a glass substrate on which a transparent protective film was formed, a transmission spectrum at a wavelength of 400 to 700 nm was measured, and then the substrate was heated at 250 ° C. for 60 minutes in a clean oven. Thereafter, similarly, a transmission spectrum at a wavelength of 400 to 700 nm was measured, a change in the transmission spectrum before and after heating was examined, and heat resistance related to the transmittance of the transparent protective film was evaluated according to the following criteria. The transmittance was measured using a microspectrophotometer (model: OSP-SP100, manufactured by Olympus Corporation).
○: Change in transmission spectrum is less than 1% ×: Change in transmission spectrum is 1% or more Pencil hardness: According to JIS K5400 (1990) pencil scratch test, 84.1 test method.

  The thermosetting resin composition for transparent protective film, the transparent protective film and the color filter of the present invention are used for a color liquid crystal display device.

Claims (6)

(1) one or more reactive groups selected from a hydroxyl group and a carboxyl group,
(2) Epoxy,
(3) ethylenic double bond,
A thermosetting resin composition for transparent protective films, comprising an acrylic copolymer having a solvent and a solvent as main components.   The thermosetting resin composition for a transparent protective film according to claim 1, wherein the epoxy is one or more selected from cyclic ethers and alicyclic epoxies.   The thermosetting resin composition for a transparent protective film according to claim 2, wherein the cyclic ether is one or more selected from oxetane acrylate and oxetane methacrylate.   The thermosetting resin composition for a transparent protective film according to claim 1, wherein the water solubility of the solvent is 20 parts by weight or less with respect to 100 parts by weight of water.   The transmittance | permeability in the visible-light area | region of 400 nm-700 nm of the transparent protective film formed by apply | coating the thermosetting resin composition for transparent protective films of Claim 1, 2, 3, or 4 and heat-curing is 90. % Transparent protective film characterized by being at least%.   5. A transparent protective film for transparent protective film according to claim 1, 2, 3 or 4, wherein a pixel made of red, green and blue or a pixel made of yellow, magenta and cyan is provided on a transparent substrate. A color filter formed with a transparent protective film of a resin composition.

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