Photosensitive resin composition, color filter and liquid crystal display device

Abstract

The present invention relates to a photosensitive resin composition comprising: (a) 5-25 wt% of an alkali-soluble resin; (b) 10-75 wt% of a black pigment; (c) 5-25 wt% of a vinyl group-containing unsaturated monomer; (d) 1-15 wt% of a photoinitiator; (e) 0.5-10 wt% of an epoxy cross-linking agent and a silane coupling agent; (f) other additives; wherein the alkali-soluble resin (a) is prepared by copolymerization of polymeric monomers including an unsaturated compound containing a phenyl group, an unsaturated compound containing a bridging group, (meth) acrylic acid and C1-C6 alkyl (meth) acrylate. The photosensitive resin composition provided by the invention has excellent developability, and an obtained cured film also shows relatively high shading property and adhesive force under high temperature and high humidity. The invention also relates to a color filter obtained from the photosensitive resin composition and a liquid crystal display device.

Description

Technical Field

[0001] The present invention belongs to the field of photosensitive electronic materials, and particularly relates to a photosensitive resin composition, a color filter, and a liquid crystal display device. Background Art

[0002] In recent years, with the development of various liquid crystal display technologies, in order to improve the contrast and display quality of current liquid crystal displays, a black matrix is generally placed in the color filter stripes and in the dot gaps. The function of this black matrix is to prevent disadvantages such as a decrease in contrast and a decrease in color purity caused by light leakage between pixels.

[0003] Nowadays, the industry has higher and higher requirements for the light-shielding performance of the black matrix. A common strategy is to improve the light-shielding performance by increasing the amount of black pigment used. Patent application CN 113741146 A discloses a black photosensitive resin composition, which contains an alkali-soluble resin, a vinyl-containing unsaturated compound, a photoinitiator, a solvent, a black pigment, a polycarbonate diol, and a specific compound. In this photosensitive resin composition for the black matrix, a specific alkali-soluble resin and a high content of black pigment are used to improve the light-shielding performance of the black pigment photosensitive resin composition. In the prior art, the light-shielding performance can be improved by using a photosensitive resin composition with an increased black pigment content. However, under high temperature and high humidity conditions, the above-mentioned photosensitive resin composition is prone to problems such as "flowering" after development, resulting in poor reliability.

[0004] In the prior art, heat-resistant epoxy groups are usually introduced into the resin to improve the tolerance performance. Patent application CN104238266 A discloses a photosensitive resin composition and a black matrix, a color filter, and a liquid crystal display including the same. The photosensitive resin composition contains an alkali-soluble resin having at least two epoxide compounds, having at least one carboxyl group and at least one vinyl unsaturated group, a vinyl-containing unsaturated compound, a photoinitiator, a solvent, and a black pigment. In this photosensitive resin composition for the black matrix, the reliability of the black pigment photosensitive resin composition under high temperature and high humidity is improved by introducing a specific alkali-soluble resin. In addition, patent application CN 103324031A discloses a black photosensitive resin composition. The photosensitive resin composition contains an alkali-soluble resin, a polysiloxane polymer, a vinyl-containing unsaturated compound, a photoinitiator, a solvent, a black pigment, and a light stabilizer. These photosensitive resins contain multiple epoxy groups, and the light stabilizer contains an ultraviolet absorber or a hindered amine compound. This photosensitive resin composition has better stability over time, and the formed black matrix has better heat resistance at high temperatures. However, while improving the heat resistance, the compatibility between the resin and other components decreases, resulting in a decrease in developability and light-shielding performance.

[0005] In view of this, there is still a need to develop a black photosensitive resin composition having excellent developability and excellent light-shielding properties and adhesion after curing under high temperature and high humidity conditions. SUMMARY OF THE INVENTION

[0006] For this purpose, on the one hand, the present invention provides a photosensitive resin composition comprising:

[0007] (a) An alkali-soluble resin, 5-25% by weight, preferably 8-20% by weight;

[0008] (b) A black pigment, 10-75% by weight, preferably 20-70% by weight;

[0009] (c) A vinyl-containing unsaturated monomer, 5-25% by weight, preferably 8-20% by weight;

[0010] (d) A photoinitiator, 1-15% by weight, preferably 2-10% by weight;

[0011] (e) An epoxy crosslinking agent and a silane coupling agent, 0.5-10% by weight, preferably 1-8% by weight;

[0012] (f) Other additives;

[0013] wherein the contents of the respective components are based on 100% by weight of the total solid content of the composition,

[0014] wherein the alkali-soluble resin (a) is prepared by copolymerization of polymerization monomers including a phenyl-containing unsaturated compound, a bridging group-containing unsaturated compound, (meth)acrylic acid, and a C1-C6 alkyl (meth)acrylate,

[0015] wherein the content of the phenyl- and bridging group-containing unsaturated compound is 20-90% by weight, preferably 30-85% by weight, more preferably 40-83% by weight, still more preferably 60-80% by weight, based on the total weight of all the polymerization monomers for preparing the alkali-soluble resin.

[0016] On the second aspect, the present invention further provides a color filter prepared from the photosensitive resin composition described in the first aspect.

[0017] On the third aspect, the present invention further provides a liquid crystal display device comprising the color filter described in the second aspect.

[0018] When using the alkali-soluble resin of the present invention, the photosensitive resin composition of the present invention has excellent developability, and the resulting cured film also exhibits high light-shielding properties and adhesion under high temperature and high humidity conditions. DETAILED DESCRIPTION OF THE INVENTION

[0019] The specific implementation modes of the present invention will be described in detail below. Unless otherwise specified, the implementation modes can be combined with each other. Although these disclosed implementation modes are for illustrative purposes, it should be understood that the present invention is not limited thereto, and those skilled in the art can make various modifications, additions, and substitutions to the present invention without departing from the scope and essence of the present invention.

[0020] In the present invention, "resin" generally contains a solvent component (such as for reducing viscosity and facilitating operation). However, when calculating material ratios, for example, only the component without solvent is usually considered, which is well-known to those skilled in the art.

[0021] In the present invention, unless otherwise stated, all operations are carried out at room temperature (25 °C) and normal pressure (101 KPa); unless otherwise stated, the contents of the present invention are expressed in weight fractions (weight %). In addition, regarding the dosage "parts", unless otherwise specified, it refers to parts by weight.

[0022] In the present invention, the solid content is determined according to the test method for unsaturated polyester resins GB / T 7193 - 2008.

[0023] On the one hand, the present invention provides a photosensitive resin composition, which comprises the following components:

[0024] (a) An alkali-soluble resin, 5 - 25 wt%, preferably 8 - 20 wt%;

[0025] (b) A black pigment, 10 - 75 wt%, preferably 20 - 70 wt%;

[0026] (c) A vinyl-containing unsaturated monomer, 5 - 25 wt%, preferably 8 - 20 wt%;

[0027] (d) A photoinitiator, 1 - 15 wt%, preferably 2 - 10 wt%;

[0028] (e) An epoxy crosslinking agent and a silane coupling agent, 0.5 - 10 wt%, preferably 1 - 8 wt%;

[0029] (f) Other additives;

[0030] Wherein the contents of each component are based on 100 wt% of the total solid content of the composition,

[0031] Wherein the alkali-soluble resin (a) is prepared by copolymerization of polymerization monomers including a phenyl-containing unsaturated compound, a bridge-linked group-containing unsaturated compound, (meth)acrylic acid, and a C1 - C6 alkyl (meth)acrylate,

[0032] The content of the unsaturated compound containing a phenyl group and a bridging group is 20 to 90% by weight, preferably 30 to 85% by weight, more preferably 40 to 83% by weight, still more preferably 60 to 80% by weight, based on the total weight of all the polymerization monomers for preparing the alkali-soluble resin.

[0033] Alkali-soluble resin

[0034] In the photosensitive resin composition of the present invention, the alkali-soluble resin (a) is prepared by copolymerization of polymerization monomers including an unsaturated compound containing a phenyl group, an unsaturated compound containing a bridging group, (meth)acrylic acid, and a C1-C6 alkyl (meth)acrylate (i.e., the polymerization monomers for preparing the alkali-soluble resin). Preferably, the polymerization monomers may further include compounds prepared by reacting a methacrylate having a hydroxyl group with a dicarboxylic acid compound, such as 2-methacryloyloxypropyl maleic acid, 2-methacryloyloxypropyl phthalic acid, 2-methacryloyloxypropyl succinic acid, etc.; compounds prepared by reacting a methacrylate having a hydroxyl group with a carboxylic anhydride compound, such as 2-hydroxyethyl acrylate, pentaerythritol trimethacrylate, trimethylolpropane triacrylate, etc.

[0035] In the present invention, the "C1-C6 alkyl" in the C1-C6 alkyl (meth)acrylate may be methyl, ethyl, propyl (such as n-propyl or isopropyl), butyl (such as n-butyl, sec-butyl, isobutyl or tert-butyl), pentyl or hexyl.

[0036] In a preferred embodiment, the unsaturated compound containing a phenyl group is selected from styrene and N-phenylmaleimide; the unsaturated compound containing a bridging group is selected from isobornyl (meth)acrylate.

[0037] In a preferred embodiment, in all the polymerization monomers for preparing the alkali-soluble resin, the content of the unsaturated compound containing a phenyl group may be 15 to 70% by weight, preferably 25 to 65% by weight, more preferably 30 to 63% by weight, still more preferably 40 to 60% by weight.

[0038] In a preferred embodiment, in all the polymerization monomers for preparing the alkali-soluble resin, the content of the unsaturated compound containing a phenyl group may be 10 - 80 mol%, preferably 20 - 75 mol%, more preferably 25 - 70 mol%, still more preferably 40 - 65 mol%.

[0039] In a preferred embodiment, the unsaturated compound containing a phenyl group is selected from styrene and N-phenylmaleimide, and the weight ratio of styrene to N-phenylmaleimide may be (1 - 3):1, preferably (1.5 - 2.5):1.

[0040] In a preferred embodiment, among all the polymerization monomers for preparing the alkali-soluble resin, the content of the unsaturated compound containing a bridging group may be 5 to 30% by weight, preferably 8 to 25% by weight, more preferably 10 to 23% by weight, and still more preferably 15 to 22% by weight.

[0041] In a preferred embodiment, among all the polymerization monomers for preparing the alkali-soluble resin, the molar percentage of the unsaturated compound containing a bridging group may be 2 - 20 mol%, preferably 3 - 15 mol%, more preferably 4 - 13 mol%, and still more preferably 6 - 12 mol%.

[0042] In a preferred embodiment, among all the polymerization monomers for preparing the alkali-soluble resin of the present invention, the sum of the molar percentages of the unsaturated compounds containing a phenyl group and a bridging group may be 20 - 85 mol%, preferably 30 - 80 mol%, more preferably 30 - 78 mol%, and still more preferably 50 - 75 mol%.

[0043] In a preferred embodiment, the weight ratio of the unsaturated compound containing a phenyl group to the unsaturated compound containing a bridging group may be (1 - 5):1, preferably (2 - 4):1, and more preferably (2.5 - 3.5):1.

[0044] In a preferred embodiment, the polymerization monomers for preparing the alkali-soluble resin include (meth)acrylic acid, C1 - C6 alkyl (meth)acrylate, isobornyl (meth)acrylate, N-phenylmaleimide, and styrene, preferably (meth)acrylic acid, methyl (meth)acrylate, n-butyl (meth)acrylate, isobornyl (meth)acrylate, N-phenylmaleimide, and styrene. The above monomers can be used to prepare the alkali-soluble resin by copolymerization.

[0045] In a preferred embodiment, the alkali-soluble resin used in the present invention can be prepared by a method comprising the following steps:

[0046] (1) Based on a total of 100 parts by weight, weigh 2 to 15 parts (preferably 3 to 5 parts) of (meth)acrylic acid, 2 to 15 parts (preferably 3 to 6 parts) of methyl (meth)acrylate, 1 to 10 parts (preferably 2 to 4 parts) of n-butyl (meth)acrylate, 4 to 15 parts (preferably 7 to 12 parts) of isobornyl (meth)acrylate, 4 to 15 parts (preferably 7 to 12 parts) of N-phenylmaleimide, 5 to 25 parts (preferably 15 to 24 parts) of styrene, 30 to 60 parts (preferably 40 to 55 parts) of a solvent, and 0.1 to 5 parts (preferably 0.2 to 1 part) of n-dodecyl mercaptan. Add the above raw materials into a reaction device and stir well.

[0047] (2) Weigh 0.15 to 0.50 parts by weight of a free copolymerization chain initiator (such as azobisisobutyronitrile), and dissolve it in a solvent (such as methyl ethyl ketone), mix evenly and set aside;

[0048] (3) Place the reaction device at 70 to 120 °C, under nitrogen protection. When the temperature is stable at 80 to 90 °C, start stirring, and dropwise add the mixed solution in step (2). The addition is completed within 0.2 to 0.5 hours;

[0049] (4) After the dropwise addition, continue stirring at 80 to 90 °C for 4 to 10 hours. After the reaction is completed, wait for it to cool to room temperature, and add 40 to 60 parts by weight of a solvent (such as propylene glycol methyl ether acetate) until the resin solid content is 30 to 40 wt%, continue stirring for 10 to 40 minutes, and then end the reaction to obtain an alkali-soluble resin.

[0050] In a preferred embodiment, the alkali-soluble resin comprises a resin having the following general formula (I):

[0051]

[0052] Where n = Z + X + Y + M + K + N, and 0.2 ≤ (Y + M + N) / n ≤ 0.8;

[0053] Preferably, n = Z + X + Y + M + K + N, preferably 6 ≤ n ≤ 300, more preferably 20 ≤ n ≤ 250, still more preferably 50 ≤ n ≤ 150, and / or, 0.20 ≤ (Y + M + N) / n ≤ 0.85, preferably 0.30 ≤ (Y + M + N) / n ≤ 0.80, more preferably 0.5 ≤ (Y + M + N) / n ≤ 0.75.

[0054] In a preferred embodiment, the amount of the alkali-soluble resin can be 5 - 25 wt%, preferably 8 - 20 wt%, more preferably 10 to 15 wt%, and further preferably 12 to 15 wt%, based on 100 wt% of the total solid content of the photosensitive resin composition.

[0055] Black pigment

[0056] The black pigment is preferably a black pigment having heat resistance, light resistance, and solvent resistance. In the present invention, examples of the black pigment include: black organic pigments such as perylene black, cyanine black, or aniline black; among pigments such as red, yellow, blue, green, cyanine, and magenta, two or more pigments are selected and mixed to form a mixed-color organic pigment close to black; carbon black; chromium oxide; iron oxide; light-shielding materials such as titanium black or graphite, wherein the carbon black specifically includes C.I. pigment black 7 or products manufactured by Mitsubishi Chemical (product names MA100, MA230, MA8, #970, #1000, #2350, #2650). The above black pigments can be used alone or in combination.

[0057] Considering the heat resistance, light resistance, and solvent resistance of the black pigment itself, the black pigment used in the present invention is preferably carbon black, such as MA100 or MA230 sold by Mitsubishi Chemical.

[0058] In a preferred embodiment, the amount of the black pigment is 10 - 75% by weight, preferably 20 - 70% by weight, more preferably 40 - 65% by weight, and still more preferably 50 - 60% by weight, based on 100% by weight of the total solid content of the photosensitive resin composition.

[0059] Vinyl-containing unsaturated monomer

[0060] The vinyl-containing unsaturated monomer (c) is mainly a compound that undergoes free copolymerization under the action of the photoinitiator (d), and is classified into monofunctional monomers, difunctional monomers, and polyfunctional monomers according to the number of vinyl unsaturated groups. The present invention preferably uses difunctional monomers and polyfunctional monomers, and most preferably polyfunctional monomers.

[0061] Specific examples of the monofunctional monomer include, but are not limited to: one or more of vinylcaprolactam, N-vinylpyrrolidone, borneol acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, (meth)acrylate-2-hydroxyethyl, (meth)acrylate-2-hydroxypropyl, glycidyl (meth)acrylate, acrylamide, N,N-dimethylacrylamide, phenoxyethyl acrylate, (meth)acrylate methyl, (meth)acrylate butyl, and ethyl acrylate.

[0062] Specific examples of the difunctional monomer include, but are not limited to: one or more of triethylene glycol di(meth)acrylate, di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, and dicyclopentene di(meth)acrylate.

[0063] Specific examples of the polyfunctional monomer include, but are not limited to: one or more combinations of trimethylolpropane triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, tris(acryloyloxyethyl)isocyanurate, trihydroxypropane (meth)acrylate, pentapentaerythritol undecaacrylate, etc., and dipentaerythritol hexaacrylate is preferred.

[0064] In a preferred embodiment, the vinyl-containing unsaturated monomer is different from the polymerization monomer used to prepare the alkali-soluble resin.

[0065] In a preferred embodiment, the amount of the vinyl-containing unsaturated monomer can be 5-25% by weight, preferably 8-20% by weight, more preferably 10-18% by weight, and even more preferably 13-16% by weight, based on 100% by weight of the total solid content of the photosensitive resin composition.

[0066] Photoinitiator

[0067] The photoinitiator in the present invention can be those commonly used in the art. The photoinitiator includes but is not limited to oxime ester initiators or a composition of oxime ester initiators and other photoinitiators. The photoinitiator is preferably one of OXE01, OXE02, and OXE03 produced by BASF Corporation.

[0068] In a preferred embodiment, the amount of the photoinitiator can be 1-15% by weight, preferably 2-10% by weight, more preferably 5-9% by weight, based on 100% by weight of the total solid content of the photosensitive resin composition.

[0069] Epoxy crosslinking agent and silane coupling agent

[0070] The weight ratio of the epoxy crosslinking agent to the silane coupling agent in the present invention can be 1:(0-10), preferably 1:(0.1-2), more preferably (0.2-1.5):1, and even more preferably 1:(0.25-0.50). Preferably, the weight ratio of the epoxy crosslinking agent to the silane coupling agent can also be 1:(0.85-1.1). In a preferred embodiment, the epoxy crosslinking agent has the following general formula (II):

[0071]

[0072] Wherein, R 1 , R 2 , R 3 are each independently an alkylene group having 1-12 carbon atoms, preferably an alkylene group having 1-6 carbon atoms, such as methylene, ethylene or propylene. Preferably, the epoxy crosslinking agent is isocyanuric acid tris(2,3-epoxypropyl) ester.

[0073] In a preferred embodiment, the silane coupling agent is preferably one or more of vinyltrimethoxysilane and vinyltris(2-methoxyethoxy)silane.

[0074] In a preferred embodiment, the amount of the epoxy crosslinking agent can be 0.5 - 10% by weight, preferably 1 - 8% by weight, more preferably 2 - 5% by weight, still more preferably 2.5 - 4% by weight, based on 100% by weight of the total solid content of the photosensitive resin composition.

[0075] In a preferred embodiment, the amount of the silane coupling agent can be 0 - 10% by weight, preferably 0.5 - 6% by weight, more preferably 1.0 - 4.5% by weight, still more preferably 2.5 - 3.5% by weight, based on 100% by weight of the total solid content of the photosensitive resin composition.

[0076] In a preferred embodiment, the sum of the amounts of the epoxy crosslinking agent and the silane coupling agent can be 0.5 - 10% by weight, preferably 1 - 8% by weight, preferably 2 - 7.5% by weight, more preferably 4 - 7% by weight, still more preferably 5 - 6.5% by weight, based on 100% by weight of the total solid content of the photosensitive resin composition.

[0077] Other additives

[0078] The photosensitive resin composition of the present invention may further comprise other additives. The additives include surfactants, fillers, antioxidants, etc.

[0079] The above surfactants can be selected from ionic, anionic, non-ionic, amphoteric surfactants or any of the above. The above surfactants include, but are not limited to: polyoxyethylene alkyl ethers such as polyoxyethylene dodecyl ether and polyoxyethylene stearyl ether; sorbitan fatty acid esters; fatty acid-modified polyesters, etc., and one or more combinations thereof are used. Specific examples are: KP (Shin-Etsu Chemical Co., Ltd.), SF-8427 (Toray Dow Corning Silicone Co., Ltd.), Asahi Guard (Asahi Glass Co., Ltd.) or SINOPOL E8008 (Chuo Nippon Synthetic Chemical Co., Ltd.), etc.

[0080] Specific examples of the above fillers include, but are not limited to, powder particles such as glass and aluminum, and their particle sizes meet the usage requirements in the art.

[0081] Specific examples of the above antioxidants include, but are not limited to: 2,2'-thiobis(4-methyl-6-tert-butylphenol) and 2,6-di-tert-butylphenol.

[0082] In a preferred embodiment, the amount of each of the above other additives can be 0 to 15% by weight, preferably 0.1 to 8% by weight, more preferably 0.5 to 6% by weight, based on 100% by weight of the total solid content of the photosensitive resin composition.

[0083] Solvent

[0084] In the present invention, examples of the solvent include, but are not limited to, one or more of propylene glycol methyl ether acetate, propylene glycol monomethyl ether, cyclohexanone, N-methylpyrrolidone, 3-methoxybutyl acetate, 3-methoxy-1-butanol, and diethylene glycol dimethyl ether. In the present invention, the preferred solvent is selected from one or more of propylene glycol methyl ether acetate, cyclohexanone, and N-methylpyrrolidone. In addition, the solvent of the present invention may also include other solvents commonly used in the art.

[0085] The solvent content of the present invention is not particularly limited and can be appropriately set according to the solid content required for the resin composition. Preferably, the solid content of the photosensitive resin composition of the present invention can be 10-60%, preferably 15 to 50%, more preferably 18 to 45%, and still more preferably 25 to 40% by weight.

[0086] Preparation of the photosensitive resin composition

[0087] The photosensitive resin composition of the present invention can be prepared by the following method: Weigh a certain amount of alkali-soluble resin (a), black pigment (b), vinyl-containing unsaturated monomer (c), photoinitiator (d), epoxy crosslinking agent, silane coupling agent (e), and other additives (f) and solvent by weight percentage, and shake at room temperature to mix the photosensitive resin composition evenly, thereby obtaining the required photosensitive resin composition. If the photosensitive resin composition uses solid components, grinding and filtration operations can also be performed.

[0088] In a second aspect, the present invention also provides a color filter prepared from the photosensitive resin composition described in the first aspect.

[0089] The black matrix is prepared by sequentially coating the photosensitive resin composition of the present invention on a substrate (such as a glass substrate), followed by pre-baking, exposure, development, and post-baking treatments. More specifically, the black matrix is obtained as follows: The photosensitive resin composition of the present invention is coated on the substrate by spin coating, then the solvent on the substrate is removed by vacuum drying and pre-baking, and a specific pattern is formed by exposure. The excess part is washed away by flushing with a developer, and then post-baking treatment is performed to finally form the black matrix.

[0090] During the preparation process of the above-mentioned black matrix, the coating rotation speed of the photosensitive resin composition can be determined according to specific film thickness requirements. The film thickness is generally 1.0 ± 0.1 um. The above-mentioned reduced-pressure drying can be carried out at a pressure of less than 200 mmHg for 1 s to 2 s; the pre-baking treatment is generally carried out at 80 °C - 120 °C for 1 minute to 2 minutes. After the pre-baking treatment, exposure is carried out according to the specified center parameters, and then development is carried out at a temperature of 23 ± 1 °C. The developer is generally an alkaline compound such as potassium hydroxide, sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, diethylamine, etc. The concentration of the developer is generally 0.043 weight percentage (wt%) or 0.055 wt%.

[0091] Generally speaking, after treatment with the developer, a substrate with a specific pattern is formed, which is rinsed with water and then dried (such as blowing off the excess water with an air gun and air-drying it), and then placed in an oven for post-baking treatment. The post-baking temperature is 200 - 240 °C, and the post-baking time is 15 minutes to 60 minutes. After the above-mentioned processes, a specific black pattern can be formed on the substrate.

[0092] The photosensitive resin compositions of various colors (red, green, and blue) are coated on the substrate on which a specific black pattern has been formed, and the processes of coating, reduced-pressure drying, pre-baking, exposure, development, and post-baking are repeated in sequence to form red, green, and blue images in sequence, and a color filter with a black pattern and red, green, and blue images can be formed.

[0093] In a third aspect, the present invention also provides a liquid crystal display device including the color filter described in the second aspect.

[0094] The color filter of the present invention and the substrate provided with thin film transistors (TFTs) are arranged opposite to each other, and a gap (cell gap) is provided between the two. Then, the surrounding parts of the color filter and the substrate are bonded with an adhesive and an injection hole is left. Then, liquid crystal is injected into the gap separated by the adhesive and on the substrate surface through the injection hole, and finally the injection hole is sealed to form a liquid crystal layer. Subsequently, a liquid crystal display element is manufactured by providing polarizing plates on the other side of the color filter in contact with the liquid crystal layer and the other side of the substrate in contact with the liquid crystal layer.

[0095] The liquid crystal compound or liquid crystal composition used above is not particularly limited. Any liquid crystal compound or liquid crystal composition can be used. The above-mentioned liquid crystal alignment film is used to restrict the alignment of liquid crystal molecules, and its type is not particularly limited and can be either an inorganic substance or an organic substance. In addition, the technology for forming the liquid crystal alignment film is common knowledge in the field to which the present invention belongs, so it will not be elaborated here.

[0096] Hereinafter, the present invention will be described in detail through specific examples and comparative examples.

[0097] Examples

[0098] Synthesis of alkali-soluble resin A (the present invention)

[0099] (1) Weigh 12 parts of methacrylic acid, 12 parts of methyl methacrylate, 6 parts of n-butyl methacrylate, 5 parts of isobornyl methacrylate, 5 parts of N-phenylmaleimide, 10 parts of styrene, 49.5 parts of propylene glycol monomethyl ether acetate, and 0.5 part of n-dodecyl mercaptan according to 100 parts by weight of the total weight. Add the above raw materials into a four-necked flask and stir well;

[0100] (2) Weigh 0.15 part of azobisisobutyronitrile as the chain initiator for free copolymerization and dissolve it fully in butanone. Mix well and set aside;

[0101] (3) Place the four-necked flask in an 85°C oil bath. Under nitrogen protection, when the temperature stabilizes at 85°C, start stirring and slowly add the mixed solution in step (2). The addition is completed in half an hour;

[0102] (4) After the addition is completed, continue stirring at 85°C for 8 h. After the reaction is completed, wait for it to cool to room temperature and add 48 parts of propylene glycol monomethyl ether acetate until the resin solid content is 35%. Continue stirring for 30 minutes to obtain alkali-soluble resin A.

[0103] Synthesis of alkali-soluble resin B (the present invention)

[0104] (1) Weigh 4 parts of methacrylic acid, 4 parts of methyl methacrylate, 2 parts of n-butyl methacrylate, 10 parts of isobornyl methacrylate, 10 parts of N-phenylmaleimide, 20 parts of styrene, 49.5 parts of propylene glycol monomethyl ether acetate, and 0.5 part of n-dodecyl mercaptan according to 100 parts by weight of the total weight. Add the above raw materials into a four-necked flask and stir well;

[0105] (2) Weigh 0.15 part of azobisisobutyronitrile as the chain initiator for free copolymerization and dissolve it fully in butanone. Mix well and set aside;

[0106] (3) Place the four-necked flask in an 85°C oil bath. Under nitrogen protection, when the temperature stabilizes at 85°C, start stirring and slowly add the mixed solution in step (2). The addition is completed in half an hour;

[0107] (4) After the addition is completed, continue stirring at 85°C for 8 h. After the reaction is completed, wait for it to cool to room temperature and add 48 parts of propylene glycol monomethyl ether acetate until the resin solid content is 35%. Continue stirring for 30 minutes to obtain alkali-soluble resin B.

[0108] Synthesis of alkali-soluble resin C (not the present invention)

[0109] (1) Weigh 20 parts of methacrylic acid, 20 parts of methyl methacrylate, 10 parts of n-butyl methacrylate, 49.5 parts of propylene glycol methyl ether acetate, and 0.5 part of n-dodecyl mercaptan according to 100 parts by total weight. Add the above raw materials into a four-necked flask and stir well.

[0110] (2) Weigh 0.15 part of azobisisobutyronitrile as the chain initiator for free copolymerization, and fully dissolve it in methyl ethyl ketone, mix well and set aside.

[0111] (3) Place the four-necked flask in an 85°C oil bath. Under nitrogen protection, when the temperature is stable at 85°C, start stirring and slowly add the mixed solution in step (2). The addition is completed in half an hour.

[0112] (4) After the addition is complete, continue stirring at 85°C for 8 h. After the reaction is completed, wait for it to cool to room temperature and add 48 parts of propylene glycol methyl ether acetate to make the resin solid content 35%. Continue stirring for 30 minutes to obtain the alkali-soluble resin C.

[0113] Preparation of the photosensitive resin composition

[0114] Example 1

[0115] The preparation process is as follows: By weight, mix 5 parts of alkali-soluble resin A (based on its active ingredient), 20 parts by weight of black pigment MA100, 5 parts of dipentaerythritol hexaacrylate (DPHA), 3 parts of photoinitiator (OEX01), 0.2 part of isocyanuric acid triglycidyl ester (TGIC) epoxy crosslinking agent, and 1.8 parts of vinyltris(2-methoxyethoxy)silane coupling agent. Then add 30 parts of propylene glycol methyl ether acetate, 25 parts of cyclohexanone, and 10 parts of N-methylpyrrolidone and stir to dissolve to obtain the corresponding photosensitive resin composition.

[0116] Examples 2-11 and Comparative Examples 1-4

[0117] Similar to the preparation process of the photosensitive resin composition in Example 1, the difference lies in the type of alkali-soluble resin and the amounts of isocyanuric acid triglycidyl ester (TGIC) epoxy crosslinking agent and vinyltris(2-methoxyethoxy)silane coupling agent added, and the amounts of the other components remain unchanged. The details are shown in Table 1.

[0118] Table 1

[0119]

[0120] Preparation of the black matrix

[0121] The photosensitive resin compositions obtained in Examples 1-11 and Comparative Examples 1-4 were spin-coated on glass substrates at adjusted rotation speeds to a target film thickness of 1 μm; then, they were dried under reduced pressure at 120 mmHg for 2 s and pre-baked at 100 °C for 90 s to remove the solvent on the substrates; and a specific pattern was formed by exposure through a photomask at 35 mJ / cm 2 ². After development by flushing with a 0.043 wt% KOH developer solution for 80 s to wash away the excess, post-baking treatment was carried out at 230 °C for 24 min, and finally a cured film of the photosensitive resin composition of the present invention, i.e., a black matrix, was formed.

[0122] Evaluation method

[0123] <Adhesion>

[0124] According to the cross-hatch method of the adhesion test in JIS.5400(1900)8.5.72, using a cross-hatch cutter, one cut was made horizontally and vertically on the above-mentioned black matrix to form 100 small squares. After cleaning with a brush, a 3M tape was pasted in the cross-hatch area, and the 3M tape was quickly pulled up. The remaining situation in the cross-hatch area was observed, and reliability evaluation was carried out according to the following criteria:

[0125] 5B: The edges of the cuts are completely smooth, and there is no peeling at the edges of the squares.

[0126] 4B: There are small pieces of peeling at the intersections of the cuts, and the actual damage in the cross-hatch area does not exceed 5%.

[0127] 3B: There is peeling at the edges and / or intersections of the cuts, and the area is greater than 5% but less than 15%.

[0128] 2B: There is partial peeling or large-scale peeling along the edges of the cuts, or some squares are peeled off entirely. The peeled area exceeds 15% but is less than 35%.

[0129] 1B: There is large-scale peeling at the edges of the cuts or some squares are partially or completely peeled off, and the area is greater than 35% - 65% of the cross-hatch.

[0130] 0B: Exceeding the previous grade.

[0131] <Adhesion under high temperature and high humidity conditions>

[0132] The above-mentioned black matrix was immersed in a water bath at 120 °C and 1 atm for 8 hours, and according to the cross-hatch method of the adhesion test in JIS.5400(1900)8.5.72, using a cross-hatch cutter, one cut was made horizontally and vertically on the above-mentioned black matrix to form 100 small squares. After cleaning with a brush, a 3M tape was pasted in the cross-hatch area, and the 3M tape was quickly pulled up. The remaining situation in the cross-hatch area was observed, and the evaluation criteria were the same as above.

[0133] <Optical density>

[0134] The test was carried out using the Xrite-361 densitometer of X-Rite, USA. The optical density (OD) represents the light-shielding ability of the material, and is usually measured by OD / μm. The larger the OD value, the better the light-shielding performance; conversely, the smaller the value, the worse the light-shielding performance.

[0135] <Resolution>

[0136] The minimum line width of the photoresist pattern was observed and tested with a Nikon metallurgical microscope of model ECLIPSE LV150A. The line width was below 100μm, the development was clean, the pattern was complete without peeling or gaps, and it was marked as "qualified"; if the development was excessive, the pattern peeled off and the remaining pattern had gaps or the development was not clean and no pattern could be made, it was marked as "unqualified".

[0137] Table 2

[0138]

[0139] It can be seen from Table 2 that Examples 1-11 still have excellent reliability under high temperature and high humidity conditions, which indicates that the alkali-soluble resin with phenyl and bridging structures synthesized in the present invention can effectively improve the reliability under high temperature and high humidity; at the same time, by synthesizing an alkali-soluble resin with a high content of phenyl and bridging structures, its light-shielding performance is also improved.

[0140] Comparing Examples 5 and 11 with Comparative Example 1, without using the alkali-soluble resin with phenyl and bridging structures, the reliability is slightly worse under high temperature and high humidity conditions; its light-shielding performance is poor and the development performance is poor.

[0141] In addition, by comparing Examples 1-10 with Comparative Example 2 and Example 11 with Comparative Example 3, it can be seen that adding the epoxy crosslinking agent triglycidyl isocyanurate (TGIC) and increasing the dosage of TGIC can also improve the reliability and light-shielding property under high temperature and high humidity. However, when the dosage of TGIC increases to a certain amount, the adhesion or optical density after high temperature and high humidity treatment will be weakened.

[0142] In summary, the photosensitive resin composition provided by the present invention still has excellent reliability under high temperature and high humidity conditions, and can also have good display performance when used in color filters and liquid crystal display devices.

Claims

1. A photosensitive resin composition comprising: (a) alkali-soluble resin, 5-25 wt %, preferably 8-20 wt %; (b) black pigment, 10-75% by weight, preferably 20-70% by weight; (c) 5-25 wt %, preferably 8-20 wt % of vinyl-containing unsaturated monomers; (d) photoinitiator, 1-15 wt %, preferably 2-10 wt %; (e) epoxy crosslinking agent and silane coupling agent, 0.5-10 wt %, preferably 1-8 wt %; (f) other additives, The alkali-soluble resin (a) is prepared by copolymerization of monomers including an unsaturated compound containing a phenyl group, an unsaturated compound containing a bridging group, (meth)acrylic acid and a C1-C6 alkyl (meth)acrylate. The content of the unsaturated compound containing phenyl group and bridging group is 20-90 wt %, preferably 30-85 wt %, more preferably 40-83 wt %, still more preferably 60-80 wt %, based on the total weight of all polymerized monomers for preparing the alkali soluble resin.

2. The photosensitive resin composition according to claim 1, wherein the content of the unsaturated compound containing a bridging group in all polymerized monomers for preparing the alkali-soluble resin is 5 to 30 wt%, preferably 8 to 25 wt%, more preferably 10 to 20 wt%.

3. The photosensitive resin composition according to claim 1 or 2, wherein in the total polymerized monomers for preparing the alkali-soluble resin of the present invention, the sum of the molar percentages of the unsaturated compounds containing phenyl groups and bridging groups is 15-85 mol%, preferably 20-80 mol%, more preferably 30-78 mol%, and even more preferably 40-75 mol%; preferably, the unsaturated compounds containing phenyl groups are selected from styrene and N-phenylmaleimide; and the unsaturated compounds containing bridging groups are selected from isobornyl (meth)acrylate.

4. The photosensitive resin composition according to any one of claims 1 to 3, wherein the weight ratio of the unsaturated compound containing phenyl group to the unsaturated compound containing a bridging group is (1-5):1, preferably (2-4):1, more preferably (2.5-3.5):

1.

5. The photosensitive resin composition according to any one of claims 1 to 4, wherein the polymerizable monomers for preparing the alkali-soluble resin comprise (meth)acrylic acid, C1-C6 alkyl (meth)acrylate, isobornyl (meth)acrylate, N-phenylmaleimide and styrene.

6. The photosensitive resin composition according to any one of claims 1 to 5, wherein the alkali-soluble resin comprises a resin having the following general formula (I): Where n = Z + X + Y + M + K + N, and 0.2 ≤ (Y + M + N) / n ≤ 0.8; Preferably, 6≤n≤300, preferably 20≤n≤250, more preferably 50≤n≤150, and / or, 0.20≤(Y+M+N) / n≤0.85, preferably 0.30≤(Y+M+N) / n≤0.80, more preferably 0.5≤(Y+M+N) / n≤0.

75.

7. The photosensitive resin composition according to any one of claims 1 to 6, wherein the epoxy crosslinking agent has the following general formula (II): in, R1, R2, and R3 are each independently a C1-C12 alkylene group, preferably a C1-C6 alkylene group, and most preferably a methylene group; Preferably, the silane coupling agent is selected from one or more of ethylene trimethoxy silane and vinyl tris (2-methoxyethoxy) silane.

8. The photosensitive resin composition according to any one of claims 1 to 7, wherein the weight ratio of the epoxy crosslinking agent to the silane coupling agent is 1:(0-10), preferably 1:(0.1-2), more preferably (0.2-1.5):1, and even more preferably 1:(0.25-0.50). 9 . A color filter comprising the photosensitive resin composition according to claim 1 . 10 . A liquid crystal display device comprising the color filter according to claim 9 .

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