Black matrix for liquid crystal display device

Abstract

The present invention discloses a black matrix for a display device, wherein the black matrix is ​​formed by the following composition, wherein the composition includes a black pigment, an alkali-soluble resin, a photo-free radical polymerizable compound, a photo-free radical polymerization initiator, and an organic solvent, wherein the alkali-soluble resin uses a styrene acrylic copolymer having a carboxyl group, and the comonomer of the styrene acrylic copolymer having a carboxyl group includes a silicon-containing monomer and a fluorine-containing monomer. The black matrix for a display device of the present invention has fewer white spot defects, which is beneficial to improving the display effect.

Description

Technical Field

[0001] The present invention relates to the field of liquid crystal display, and in particular to a black matrix for a liquid crystal display device. Background Art

[0002] The structure of the liquid crystal panel The color liquid crystal panel is composed of a polarizing plate, a backlight, a lower glass, an ITO electrode, an alignment film, a color filter, an upper glass, etc. The role of the polarizing plate is like a fence, which will block the components perpendicular to the fence and only allow the components parallel to the fence to pass. The upper and lower polarizing plates are perpendicular to each other. The black matrix prevents light leakage from the gap between the R, G, and color films; the basic structure of the color filter glass substrate includes a glass substrate, a black matrix (BM, black matrix) shading layer, a red, green, and blue color layer (CF, color filter protective coloring layer transparent protective film layer C, overcoat) and an IT transparent conductive film layer that drives the liquid crystal. The black matrix is ​​the opaque part deposited between the three primary colors (RGB) pattern. Its main function is to prevent backlight leakage, improve display contrast, prevent color mixing and increase color purity. In the early stages of the development of color film substrates, chromium film was often used as a black matrix material. Chromium materials have the characteristics of high light shielding, thin film thickness, high stability, and easy patterning, but they also have problems such as high cost, high metal reflectivity, and chromium metal pollution. At present, resin-type black matrix materials are widely used to replace chromium films, which can be formed by coating. However, the existing black matrix is ​​prone to white spot defects. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a black matrix for a liquid crystal display device to solve the white spot problem generated after the black matrix is ​​formed.

[0004] In order to solve the above technical problems, the present invention provides a liquid crystal display device, which includes a color filter, the color filter includes a black matrix, and the black matrix is ​​formed by the following composition, the composition includes a black pigment, an alkali-soluble resin, a photo-free radical polymerizable compound, a photo-free radical polymerization initiator, and an organic solvent, the alkali-soluble resin uses a styrene acrylic copolymer with a carboxyl group, and the copolymer monomer of the styrene acrylic copolymer with a carboxyl group includes a silicon-containing monomer and a fluorine-containing monomer. Among them, the content of the silicon-containing monomer is greater than the content of the fluorine-containing monomer.

[0005] In an alternative embodiment, the alkali-soluble resin has a carboxyl group on the side chain and further has an ethylenically unsaturated group on the side chain.

[0006] An optional embodiment is that the composition comprises 5-20 parts by weight of black pigment, 4-10 parts by weight of alkali-soluble resin, 5-15 parts by weight of photo-radical polymerizable compound, 3-10 parts by weight of photo-radical polymerization initiator, and 60-90 parts by weight of organic solvent, and the weight ratio of black pigment to alkali-soluble resin is 1-4, preferably 1-2.5.

[0007] In an optional embodiment, the composition comprises 5-15 parts by weight of a colorant, 4-10 parts by weight of an alkali-soluble resin, 5-15 parts by weight of a photo-radical polymerizable compound, 3-8 parts by weight of a photo-radical polymerization initiator, and 60-90 parts by weight of an organic solvent.

[0008] An optional embodiment is that the organic solvent contains at least one of cyclopentanone, cyclohexanone, ethyl lactate, ethyl ethoxypropionate, 3-methoxybutyl acetate, ethyl 3-ethoxy-3-imidopropionate, propylene glycol monomethyl ether acetate, propylene glycol diacetate, propylene glycol monomethyl ether, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl cellosolve acetate, ethyl lactate, diethylene glycol dimethyl ether, butyl acetate, methyl 3-methoxypropionate, ethyl carbitol acetate, and butyl carbitol acetate.

[0009] An optional embodiment is that the acid value of the alkali-soluble resin is 20 to 200 (mgKOH / g)

[0010] In an optional embodiment, the weight average molecular weight of the alkali-soluble resin is 3,000-50,000.

[0011] An optional embodiment is that the silicon-containing monomer is N-(3-(3-methoxysilyl)-propyl)-acrylamide; the fluorine-containing monomer is heptadecafluorodecyl acrylate (1H,1H,2H,2H-perfluorodecyl acrylate, or 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl acrylate).

[0012] The present invention has the following beneficial and positive technical effects: the black matrix of the present invention can effectively eliminate the white spot defects of the black matrix. DETAILED DESCRIPTION

[0013] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0014] The black pigment may be an inorganic pigment such as carbon black, ferrosoferric oxide, or an organic pigment such as aniline black, perylene black, etc., and commercial products include Printex300P. The average primary particle size of the pigment is 10 to 150 nm, preferably 10 to 80 nm. The particle size is measured by scanning electron microscopy. Pigment dispersants are, for example, polymer dispersants, such as (meth) acrylic copolymers. Commercial products include: DISPER BYK-2000, DISPER BYK-2001, DISPER BYK-2070, DISPER BYK-2150, Disperbyk-107, Polyflow No.50E, etc. Relative to 100 parts by weight of the total solid content in the black pigment dispersion, the black pigment preferably contains 20 to 80 parts by weight, and more preferably 40 to 75 parts by weight. Relative to 100 parts by weight of the black pigment component, the dispersant preferably contains 5 to 50 parts by weight. Carbon black can also be used in combination with black porous titanium dioxide particles to effectively improve the shading effect.

[0015] The alkali-soluble resin uses a styrene-acrylic copolymer with a carboxyl group having an ethylenically unsaturated group on the side chain. The preparation of the copolymer uses comonomers that contain (meth) acrylic acid, (meth) acrylic acid ester, styrene, and benzylmaleimide in addition to silicon-containing monomers and fluorine-containing monomers. Among them, the silicon-containing monomer is N-(3-(3-methoxysilyl)-propyl)-acrylamide; the fluorine-containing monomer is acrylate heptadecafluorodecyl. The weight parts (ratios) of each component range as follows: 30-60 parts by weight of (meth) acrylic acid, 30-60 parts by weight of (meth) acrylic acid ester, 60-90 parts by weight of benzylmaleimide, 2-4 parts by weight of N-(3-(3-methoxysilyl)-propyl)-acrylamide; 1-3 parts by weight of acrylate heptadecafluorodecyl. Among them, the content of N-(3-(3-methoxysilyl)-propyl)-acrylamide is greater than the content of acrylate heptadecafluorodecyl.

[0016] The molecular weight of the alkali-soluble resin is preferably 3000 to 50000 (weight average molecular weight), which can simultaneously meet the requirements of adhesion and developability. The acid value of the alkali-soluble resin is in the range of 50 to 120 mgKOH / g, which can simultaneously meet the requirements of development speed, adhesion and storage stability. The content of the alkali-soluble resin is 20-100 parts by weight relative to 100 parts by weight of the black pigment. Within this range, developability, storage stability and appropriate color concentration can be balanced.

[0017] From the viewpoint of sensitivity, the photo-radical polymerizable compound is preferably ethylene glycol di(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate. The content of the photo-radical polymerizable compound is preferably 30-100 parts by weight based on 100 parts by weight of the solid content in the photosensitive resin composition. The developability and film hardness can be balanced.

[0018] The photoradical polymerization initiator is an oxime ester photoinitiator, and specifically, Irgacure OXE-01, TR-PBG-304, etc. are preferably used. The content of the photoradical polymerization initiator is 1 to 25 parts by mass based on 100 parts by mass of the photopolymerizable compound.

[0019] The composition may also contain additives such as surfactants, adhesion promoters, etc.; the solvent used preferably includes one or more of ethyl ethoxypropionate, 3-methoxybutyl acetate, propylene glycol monomethyl ether acetate, propylene glycol diacetate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl cellosolve acetate, diethylene glycol dimethyl ether, methyl 3-methoxypropionate, ethyl carbitol acetate, and butyl carbitol acetate.

[0020] Preparation of carbon black dispersion: 10 parts by weight of carbon black (special black 550), 2 parts of DISPER BYK-2150 dispersant, and 88 parts of propylene glycol diacetate were mixed and dispersed in a bead mill to obtain a carbon black dispersion.

[0021] Preparation of alkali-soluble resin 1: In a nitrogen atmosphere, 450 g of propylene glycol diacetate was added to a reaction container, followed by dropwise addition of 3 g of N-(3-(3-methoxysilyl)-propyl)-acrylamide, 1 g of 17-fluorodecyl acrylate, 75 g of benzyl maleimide, 52 g of styrene, 43 g of acrylate, 43 g of acrylic acid, 4 g of tert-butyl peroxy-2-ethylhexanoate, and 6 g of n-dodecyl mercaptan and 24 g of propylene glycol methyl ether acetate. The reaction temperature was controlled at 80-110° C. After three hours of reaction, 0.4 g of p-methoxyphenol, 28 g of glycidyl methacrylate, and 0.6 g of triethylamine were dropwise added while blowing air, and the reaction was continued for 5 hours to obtain alkali-soluble resin 1. The acid value of the resin was 85 (determined based on GB / T 2895-2008), the weight average molecular weight was 14500, and the molecular weight distribution was 1.8.

[0022] Preparation of alkali-soluble resin 2: In a nitrogen atmosphere, 450 g of propylene glycol diacetate was added to a reaction vessel, followed by dropwise addition of 1 g of 17-fluorodecyl acrylate, 75 g of benzyl maleimide, 52 g of styrene, 43 g of acrylate, 43 g of acrylic acid, 4 g of tert-butyl peroxy-2-ethylhexanoate, and 6 g of n-dodecyl mercaptan and 24 g of propylene glycol methyl ether acetate. The reaction temperature was controlled to be 80-110° C. After three hours of reaction, 0.4 g of p-methoxyphenol, 28 g of glycidyl methacrylate, and 0.6 g of triethylamine were dropwise added while blowing air, and the reaction was continued for 5 hours to obtain alkali-soluble resin 1. The acid value of the resin was 87 (determined based on GB / T 2895-2008), the weight average molecular weight was 13800, and the molecular weight distribution was 1.9.

[0023] Preparation of alkali-soluble resin 3: In a nitrogen atmosphere, 450 g of propylene glycol diacetate was added to a reaction vessel, followed by dropwise addition of 3 g of N-(3-(3-methoxysilyl)-propyl)-acrylamide, 75 g of benzyl maleimide, 52 g of styrene, 43 g of acrylate, 43 g of acrylic acid, 4 g of tert-butyl peroxy-2-ethylhexanoate, and 6 g of n-dodecyl mercaptan and 24 g of propylene glycol methyl ether acetate. The reaction temperature was controlled at 80-110° C. After three hours of reaction, 0.4 g of p-methoxyphenol, 28 g of glycidyl methacrylate, and 0.6 g of triethylamine were dropwise added while blowing air, and the reaction was continued for 5 hours to obtain alkali-soluble resin 1. The acid value of the resin was 82 (determined based on GB / T 2895-2008), the weight average molecular weight was 15,000, and the molecular weight distribution was 1.9.

[0024] Preparation of alkali-soluble resin 4: In a nitrogen atmosphere, 450 g of propylene glycol diacetate was added to a reaction vessel, followed by dropwise addition of 1 g of N-(3-(3-methoxysilyl)-propyl)-acrylamide, 3 g of 17-fluorodecyl acrylate, 75 g of benzyl maleimide, 52 g of styrene, 43 g of acrylate, 43 g of acrylic acid, 4 g of tert-butyl peroxy-2-ethylhexanoate, and 6 g of n-dodecyl mercaptan and 24 g of propylene glycol methyl ether acetate. The reaction temperature was controlled at 80-110° C. After three hours of reaction, 0.4 g of p-methoxyphenol, 28 g of glycidyl methacrylate, and 0.6 g of triethylamine were dropwise added while blowing air, and the reaction was continued for 5 hours to obtain alkali-soluble resin 1. The acid value of the resin was 85 (determined based on GB / T 2895-2008), the weight average molecular weight was 14500, and the molecular weight distribution was 1.7.

[0025] Preparation of alkali-soluble resin 5: In a nitrogen atmosphere, 450 g of propylene glycol diacetate was added to a reaction vessel, followed by dropwise addition of 75 g of benzyl maleimide, 52 g of styrene, 43 g of acrylate, 43 g of acrylic acid, 4 g of tert-butyl peroxy-2-ethylhexanoate, 6 g of n-dodecyl mercaptan, and 24 g of propylene glycol methyl ether acetate. The reaction temperature was controlled at 80-110° C. After three hours of reaction, 0.4 g of p-methoxyphenol, 28 g of glycidyl methacrylate, and 0.6 g of triethylamine were dropwise added while blowing air, and the reaction was continued for 5 hours to obtain alkali-soluble resin 1. The acid value of the resin was 85 (determined based on GB / T 2895-2008), the weight average molecular weight was 13,000, and the molecular weight distribution was 1.7.

[0026] Photosensitive composition examples (see Table 1)

[0027] Table 1

[0028]

[0029] White spot test: Spin-coat the above photosensitive resin composition on a 100mm×100mm glass substrate, vacuum dry at 80Pa for 20s, bake at 80℃ for 3 minutes on a hot plate, irradiate with an ultra-high pressure mercury lamp, and expose at 70mJ / cm2. Develop after exposure (e.g., 0.05 wt% potassium hydroxide aqueous solution, spray development at 25℃ for 60S); post-bake at 200-240℃ for 30min after development. Observe the black matrix after development with a microscope (magnification 100).

[0030] It was observed that no white spots were found in Examples 1 and 2, but in Comparative Examples 1-3, white spots (greater than 5) were generated due to the copolymerization monomer of the alkali-soluble resin, the lack of silicon-containing monomer or fluorine-containing monomer, the greater amount of fluorine-containing monomer than silicon-containing monomer, or the absence of both monomers.

[0031] This embodiment is only a preferred specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A liquid crystal display device, comprising a color filter, wherein the color filter comprises a black matrix, wherein: The black matrix is ​​formed from the following composition: The composition comprises 5-20 parts by weight of a black pigment, 4-10 parts by weight of an alkali-soluble resin, 5-15 parts by weight of a photo-free radical polymerizable compound, 3-10 parts by weight of a photo-free radical polymerization initiator, and 60-90 parts by weight of an organic solvent, wherein the weight ratio of the black pigment to the alkali-soluble resin is 1-4; The copolymer monomers of the alkali-soluble resin include 30-60 parts by weight of methacrylic acid, 30-60 parts by weight of methacrylate, 60-90 parts by weight of benzylmaleimide, 2-4 parts by weight of N-(3-(3-methoxysilyl)-propyl)-acrylamide; and 1-3 parts by weight of 1H,1H,2H,2H-perfluorodecyl acrylate, wherein the content of N-(3-(3-methoxysilyl)-propyl)-acrylamide is greater than that of 1H,1H,2H,2H-perfluorodecyl acrylate.

2. The liquid crystal display device according to claim 1, wherein: The alkali-soluble resin has a carboxyl group on the side chain and further has an ethylenically unsaturated group on the side chain.

3. The liquid crystal display device according to claim 1, wherein: The organic solvent includes at least one of cyclopentanone, cyclohexanone, ethyl lactate, ethyl ethoxypropionate, 3-methoxybutyl acetate, ethyl 3-ethoxy-3-imidopropionate, propylene glycol monomethyl ether acetate, propylene glycol diacetate, propylene glycol monomethyl ether, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl cellosolve acetate, ethyl lactate, diethylene glycol dimethyl ether, butyl acetate, methyl 3-methoxypropionate, ethyl carbitol acetate, and butyl carbitol acetate.

4. The liquid crystal display device according to claim 1, wherein: The acid value of the alkali-soluble resin is 20 to 200 mgKOH / g.

5. The liquid crystal display device according to claim 1, wherein: The weight average molecular weight of the alkali-soluble resin is 3,000-50,000.

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