OC transparent composition with low hygroscopicity and low dielectric constant for CF substrate

Abstract

The invention discloses an OC transparent composition with low hygroscopicity and a low dielectric constant for a CF substrate. The water-based ink is prepared from the following components in percentage by weight: 1 to 5 percent of hyperbranched oligomer, 1 to 5 percent of modified polybutadiene oligomer, 0.01 to 3 percent of fluorine modified calixarene oligomer, 1 to 14 percent of reactive diluent containing four to eight polymerizable functional groups, 1 to 10 percent of acrylic resin, 0.01 to 5 percent of epoxy resin, 0.2 to 0.5 percent of flatting agent, 0.1 to 5 percent of silane coupling agent, 0.1 to 5 percent of curing accelerator, 0.01 to 0.2 percent of polymerization inhibitor, 0.01 to 0.2 percent of antioxidant and 70 to 90 percent of electronic-grade organic solvent. According to the invention, the main performances of high hardness, high thermal stability, high planarization capability, high barrier property and the like of the transparent protective composition OC coating for the CF substrate can be maintained, and the OC coating has excellent low hygroscopicity and low dielectric constant, so that the energy consumption in the box forming process of a flat-panel display is greatly reduced, and the application range of the OC material in the fields of large size, high thermal stability, high planarization capability, high barrier property and the like is widened. The application range of the high-speed high-frequency LCD display screen is wide.

Description

Technical Field

[0001] The invention relates to the field of photoresists, and in particular to an OC transparent composition for a CF substrate having low hygroscopicity and low dielectric constant. Background Art

[0002] Traditional LCD display, also called liquid crystal display, is a flat and ultra-thin display device, which is mainly composed of array substrate, CF substrate, liquid crystal and polarizer. LCD has very low power consumption, so it is very popular. In the whole process of LCD display, OC coating mainly plays the role of protecting and flattening CF substrate. Specifically, it can block the overflow of trace molecules or metal ions in RGB and BM materials to protect liquid crystal. At the same time, it plays a role in flattening the difference in interlayer film thickness formed in each RGB process to adapt to the later processes such as PI liquid coating and liquid crystal dripping.

[0003] With the improvement of human living standards and the continuous construction of high-generation production lines, LCD display screens are also developing towards ultra-large size, high precision, and high frequency, and the scope of application has also expanded to ultra-large TVs, advertising screens, touch screens and other equipment. Higher requirements have also been put forward for the formulation innovation of supporting electronic chemicals. At present, the OC materials used in LCDs are mainly thermally cured. In addition to the conventional requirements for flatness, heat resistance, barrier properties, etc., there is not much attention paid to their hygroscopicity and electrical properties. In fact, when the panel size is too large, the target vacuum degree to be achieved in the box-making process will consume more energy and time, and the problem of poor hygroscopicity of OC materials will be highlighted. In order to save energy and cost and improve economic benefits, it is necessary to improve the hygroscopicity resistance of OC materials; moreover, with the high requirements of human beings on visual perception, the screen is driven to develop towards high frequency and high speed. Coupled with the vigorous development of 5G networks, higher requirements have been further put forward for the electrical properties of the materials used, requiring low dielectric constants and high voltage retention rates.

[0004] The existing OC transparent composition for CF substrate and its coating process have the following disadvantages:

[0005] 1. Currently, there are no high requirements for the low hygroscopicity of materials in the production of conventional-sized display screens. However, in the process of producing larger and larger substrates, it is found that the larger the panel size, the greater the energy consumption and time required in the vacuum stage before boxing, and the economic benefits are greatly reduced. Therefore, the problem of poor hygroscopicity of conventional OC materials becomes prominent, which limits the development of OC materials in the application field of larger-sized panels. At the same time, during the washing process, if the hygroscopicity of the OC film is poor, the polymer is more susceptible to moisture, which will generally increase the dielectric loss of the material over a wide frequency range.

[0006] 2 The dielectric constants of some photoresist materials such as RGB are basically around 4-5. Different products correspond to different semiconductor materials. However, if the OC coating material, which is closer to the liquid crystal, has a higher dielectric constant, it will have an adverse effect on the operation of the liquid crystal after power is turned on, and thus affect the service life and viewing comfort of the display. The conventional curing materials of OC materials in the existing process generally use phenolic epoxy resins, and some add anhydride curing agents. There are many hydroxyl groups and carboxyl residues in the cured products. Some products also add a certain amount of polyurethane acrylate. Although it can improve the yellowing of the entire system, the introduction of amide bonds also increases the polarity of the cured product to a certain extent, resulting in a high dielectric constant, which ultimately limits the application of these OC coating materials in the high-frequency and high-speed line communication range.

[0007] 3. Prior art literature: JP-A-9-263560 discloses a cup aromatic compound as a photocurable composition. This compound contains unsaturated double bonds and needs to be cured by adding a photoinitiator. This is different from the thermosetting process used in the present invention. If this compound is added in this scheme, it needs to be baked to form a hard film after curing, which is relatively complicated. The invention of CN116199559A also involves low-dielectric and high-heat-resistant cup aromatic resins and their preparation methods and applications. Cup aromatics containing unsaturated double bonds are prepared, which also need to be cured by adding a photoinitiator and do not contain a fluorocarbon structure. Neither of the above two patents has been applied to OC coating materials for CF substrates. In particular, there are few reports on the application of fluorine-modified cup (4) aromatic resins and polybutadiene structures in the field of CF substrates.

[0008] In summary, the existing OC coating materials for CF substrates need to be improved in terms of low hygroscopicity and low dielectric constant to meet the application requirements of the materials in large-size, high-frequency and high-speed LCD display screens. Summary of the invention

[0009] The object of the present invention is to provide an OC transparent composition for CF substrates having both low hygroscopicity and low dielectric constant.

[0010] The innovation of the present invention is that the OC coating of the transparent protective composition for CF substrate can maintain high hardness, high thermal stability, high flattening ability and high barrier properties, while making the OC coating have excellent low hygroscopicity and low dielectric constant, thus broadening the application range of the material in large-size, high-speed and high-frequency LCD display screens. To achieve the above invention purpose, the technical solution of the present invention is:

[0011] The invention discloses an OC transparent composition for a CF substrate having low hygroscopicity and low dielectric constant, comprising the following raw materials in percentage by mass: 1-5% of a hyperbranched oligomer, 1-5% of a modified polybutadiene oligomer, 0.01-3% of a fluorine-modified calixarene oligomer, 1-14% of an active diluent containing four to eight polymerizable functional groups, 1-10% of an acrylic resin, 0.01-5% of an epoxy resin, 0.2-0.5% of a leveling agent, 0.1-5% of a silane coupling agent, 0.1-5% of a curing accelerator, 0.01-0.2% of a polymerization inhibitor, 0.01-0.2% of an antioxidant, and 70-90% of an electronic grade organic solvent.

[0012] Furthermore, the hyperbranched oligomer is a hyperbranched oligomer having six to twelve acryloyloxy functional groups.

[0013] Furthermore, the modified polybutadiene oligomer is at least one of epoxidized polybutadiene oligomer, carboxyl-terminated polybutadiene oligomer, and hydroxyl-terminated polybutadiene oligomer, or a mixture of several thereof.

[0014] Furthermore, the main structure of the fluorine-modified calixarene oligomer is a calix[4-8]arene structure, the para-position structure of the phenol ring of the fluorine-modified calixarene oligomer is a perfluoroalkyl group, and the structure of the perfluoroalkyl group is (-CF2)n-CF 3， n=1~6.

[0015] Furthermore, the active diluent containing four to eight polymerizable functional groups is at least one of dipentaerythritol penta / hexaacrylate (hexafunctional accounts for 55-100%), ethoxylated dipentaerythritol hexaacrylate, caprolactone dipentaerythritol hexaacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol tetraacrylate, and tripentaerythritol octaacrylate, or a mixture of several thereof.

[0016] Furthermore, the acrylic resin is a polyacrylic acid block copolymer, and the characteristic functional groups include at least one of cyclohexyl, phenyl, epoxy, acryloxy, cyclopentadienyl, oxetanyl, dicyclopentyl and naphthyl in addition to the carboxyl group.

[0017] Furthermore, the epoxy resin is at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, o-cresol epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, maleimide epoxy resin, and hydantoin epoxy resin, or a mixture of several of them.

[0018] Furthermore, the leveling agent is at least one of an organic silicon leveling agent, an acrylate leveling agent, and a fluorocarbon leveling agent, or a mixture of several thereof;

[0019] The curing accelerator is one or a mixture of tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, nadic anhydride, trimellitic anhydride, anionic curing accelerator, maleopimaric anhydride, 2-methylimidazole, 2-phenylimidazole, tetramethyl sulfoxide;

[0020] The polymerization inhibitor is at least one of tert-butylphenol, tert-butylphenol, diethylhydroxylamine, and piperidinol oxide, or a mixture of several thereof;

[0021] The silane coupling agent is at least one of γ-aminopropyl trimethoxysilane, N-β-aminoethyl-γ-aminopropyl trimethoxysilane, N-phenyl-γ-aminopropyl trimethoxysilane, 3-glycidyloxypropyl trimethoxysilane, 3-glycidyloxypropyl triethoxysilane, (2-aminoethyl)aminomethyl trimethoxysilane, γ-isocyanate propyl trimethoxysilane, γ-isocyanate propyl triethoxysilane, γ-mercaptopropyl trimethoxysilane, γ-mercaptopropyl triethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl triethoxysilane, and β-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, or a mixture of several thereof;

[0022] The antioxidant is at least one or a mixture of aromatic amines, hindered phenols, pentaerythritol tetrapropionate, phosphites, thioethers and the like;

[0023] The electronic grade organic solvent is one or a mixture of solvents such as propylene glycol methyl ether, propylene glycol methyl ether acetate, diethylene glycol methyl ethyl ether, 3-methoxypropionic acid methyl ester, propylene glycol diacetate, 3-methoxybutyl acetate, propylene glycol monoethyl ether, diethylene glycol dimethyl ether, methyl N-amyl ketone, and methyl isobutyl ketone.

[0024] A method for preparing an OC transparent composition for a CF substrate having low hygroscopicity and low dielectric constant, comprising the following steps:

[0025] According to the formula, hyperbranched oligomers, modified polybutadiene oligomers, fluorine-modified calixarene oligomers, active diluents containing four to eight polymerizable functional groups, acrylic resins, epoxy resins, leveling agents, silane coupling agents, curing accelerators, polymerization inhibitors, antioxidants, and electronic-grade organic solvents are taken and mixed uniformly to obtain a finished product.

[0026] Furthermore, in the first step, part of the electronic-grade organic solvent and the remaining raw materials are evenly mixed, and in the second step, the remaining electronic-grade organic solvent is added and mixed evenly; a high-speed disperser is used for dispersion during mixing, and the first step is dispersed at a rotation speed of 1000-1500rpm for 10-15min, and the second step is dispersed at 1000-1500rpm for 3-5min.

[0027] The beneficial effects of the present invention are:

[0028] 1. The present invention adds fluorine-modified calixarene oligomers into the material. The fluorine-modified calixarene oligomers have multiple benzene rings, and the bowl-shaped structure formed can block the entry of water. The composition of multiple benzene rings and conjugated structures not only maintains the good heat resistance of the cured product, but also plays a hydrophobic role. In addition, the introduction of the fluorocarbon structure on the side chain causes the fluorine at the rear end of the cured film to migrate to the surface of the coating, which can further reduce the surface energy and hygroscopicity of the coating.

[0029] 2. The modified polybutadiene oligomer of the present invention contains a large amount of non-polar polybutadiene structure. The introduction of this structure not only allows the polymer to maintain excellent hydrophobic properties, but also reduces the dielectric constant of the material, while reducing a part of the extremely high brittleness caused by fluorine-modified calixarene and hyperbranched oligomers, dissipating a part of the stress, and taking into account flexibility and heat resistance while ensuring high hardness of the OC material. The most prominent highlight is that it has a non-polar structure, which can form a host-guest enveloping structure with calixarene, increase the crosslinking density of the cured product, reduce the free volume between molecules, and is conducive to eliminating the overflow or entry of small molecules, improving the barrier effect of the OC coating material, effectively reducing the hygroscopicity of the material, and further reducing the dielectric constant of the material.

[0030] 3. In the present invention, by adding hyperbranched oligomers, the crosslinking density of the material is increased after curing, forming a dense three-dimensional network and improving the barrier properties; at the same time, the main structure of the entire oligomer has almost no long-chain alkanes, which reduces the entanglement of the chain and plays a role in reducing the viscosity of the composition.

[0031] 4. The present invention can not only maintain the main properties of the transparent protective composition OC coating for CF substrates, such as high hardness, high thermal stability, high flattening ability, and high barrier properties, but also make the OC coating have excellent low hygroscopicity and low dielectric constant, which greatly reduces the energy consumption in the flat panel display box-making process and broadens the application range of the material in large-size, high-speed and high-frequency LCD display screens. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention will be described clearly and completely below.

[0033] Embodiment 1: An OC transparent composition for CF substrates having both low hygroscopicity and low dielectric constant, comprising the following raw materials in percentage by mass: 4% hyperbranched oligomer, 3.56% modified polybutadiene oligomer, 0.01% fluorine-modified calixarene oligomer, 1% active diluent containing four to eight polymerizable functional groups, 1% acrylic resin, 0.01% epoxy resin, 0.2% leveling agent, 0.1% silane coupling agent, 0.1% curing accelerator, 0.01% inhibitor, 0.01% antioxidant, and 90% electronic grade organic solvent. The hyperbranched oligomer is a hyperbranched oligomer with six to twelve acryloxy functional groups. The modified polybutadiene oligomer is an epoxidized polybutadiene oligomer. The main structure of the fluorine-modified calixarene oligomer is a calix[4-8]arene structure, and the para-position structure of the phenol ring of the fluorine-modified calixarene oligomer is a perfluoroalkyl group, and the structure of the perfluoroalkyl group is (-CF2)n-CF3, where n=1. The active diluent containing four to eight polymerizable functional groups is dipentaerythritol penta / hexaacrylate (hexaacrylate accounts for 55%). The acrylic resin is a polyacrylic block copolymer, and the characteristic functional groups include cyclohexyl in addition to carboxyl. The epoxy resin is a bisphenol A epoxy resin. The leveling agent is an organosilicon leveling agent; the curing accelerator is tetrahydrophthalic anhydride; the inhibitor is tert-butylphenol; the silane coupling agent is γ-aminopropyltrimethoxysilane; the antioxidant is an aromatic amine; and the electronic grade organic solvent is propylene glycol methyl ether.

[0034] Embodiment 2: An OC transparent composition for CF substrates having both low hygroscopicity and low dielectric constant, comprising the following raw materials in percentage by mass: 1% hyperbranched oligomer, 2% modified polybutadiene oligomer, 1% fluorine-modified calixarene oligomer, 14% active diluent containing four to eight polymerizable functional groups, 2.5% acrylic resin, 2% epoxy resin, 0.3% leveling agent, 5% silane coupling agent, 2% curing accelerator, 0.1% inhibitor, 0.1% antioxidant, and 70% electronic grade organic solvent. The hyperbranched oligomer is a hyperbranched oligomer with six to twelve acryloyloxy functional groups. The modified polybutadiene oligomer is a carboxyl-terminated polybutadiene oligomer. The main structure of the fluorine-modified calixarene oligomer is a calix[4-8]arene structure, and the para-position structure of the phenol ring of the fluorine-modified calixarene oligomer is a perfluoroalkyl group, and the structure of the perfluoroalkyl group is (-CF2)n-CF3, where n=4. The active diluent containing four to eight polymerizable functional groups is dipentaerythritol penta / hexaacrylate (hexaacrylate accounts for 80%). The acrylic resin is a polyacrylic block copolymer, and the characteristic functional groups include dicyclopentyl in addition to carboxyl. The epoxy resin is bisphenol F epoxy resin. The leveling agent is an acrylate leveling agent; the curing accelerator is methyltetrahydrophthalic anhydride; the inhibitor is tert-butylphenol; the silane coupling agent is N-β-aminoethyl-γ-aminopropyltrimethoxysilane; the antioxidant is hindered phenol; and the electronic grade organic solvent is propylene glycol methyl ether acetate.

[0035] Embodiment 3: An OC transparent composition for CF substrates having both low hygroscopicity and low dielectric constant, comprising the following raw materials in percentage by mass: 2% hyperbranched oligomer, 5% modified polybutadiene oligomer, 3% fluorine-modified calixarene oligomer, 2% active diluent containing four to eight polymerizable functional groups, 4.1% acrylic resin, 5% epoxy resin, 0.5% leveling agent, 1% silane coupling agent, 5% curing accelerator, 0.2% inhibitor, 0.2% antioxidant, and 72% electronic grade organic solvent. The hyperbranched oligomer is a hyperbranched oligomer with six to twelve acryloxy functional groups. The modified polybutadiene oligomer is a hydroxy-terminated polybutadiene oligomer. The main structure of the fluorine-modified calixarene oligomer is a calix[4-8]arene structure, and the para-position structure of the phenol ring of the fluorine-modified calixarene oligomer is a perfluoroalkyl group, and the structure of the perfluoroalkyl group is (-CF2)n-CF3, where n=6. The active diluent containing four to eight polymerizable functional groups is dipentaerythritol penta / hexaacrylate (hexaacrylate accounts for 100%). The acrylic resin is a polyacrylic block copolymer, and the characteristic functional groups include acryloxy in addition to carboxyl groups. The epoxy resin is o-cresol epoxy resin. The leveling agent is a fluorocarbon leveling agent; the curing accelerator is methyl nadic anhydride; the inhibitor is diethylhydroxylamine; the silane coupling agent is N-phenyl-γ-aminopropyl trimethoxysilane; the antioxidant is pentaerythritol tetrapropionate; and the electronic grade organic solvent is diethylene glycol methyl ethyl ether.

[0036] Embodiment 4: An OC transparent composition for CF substrates having both low hygroscopicity and low dielectric constant, comprising the following raw materials in percentage by mass: 5% hyperbranched oligomer, 1% modified polybutadiene oligomer, 0.02% fluorine-modified calixarene oligomer, 3% active diluent containing four to eight polymerizable functional groups, 10% acrylic resin, 0.02% epoxy resin, 0.4% leveling agent, 0.3% silane coupling agent, 0.2% curing accelerator, 0.02% inhibitor, 0.04% antioxidant, and 80% electronic grade organic solvent. The hyperbranched oligomer is a hyperbranched oligomer with six to twelve acryloxy functional groups. The modified polybutadiene oligomer is an epoxidized polybutadiene oligomer. The main structure of the fluorine-modified calixarene oligomer is a calix[4-8]arene structure, and the para-position structure of the phenol ring of the fluorine-modified calixarene oligomer is a perfluoroalkyl group, and the structure of the perfluoroalkyl group is (-CF2)n-CF3, where n=6. The active diluent containing four to eight polymerizable functional groups is ethoxylated dipentaerythritol hexaacrylate. The acrylic resin is a polyacrylic acid block copolymer, and the characteristic functional groups include naphthyl in addition to carboxyl. The epoxy resin is an alicyclic epoxy resin. The leveling agent is an organosilicon leveling agent; the curing accelerator is nadic anhydride; the inhibitor is piperidinol oxide; the silane coupling agent is 3-glycidyloxypropyltrimethoxysilane; the antioxidant is a phosphite; and the electronic grade organic solvent is methyl 3-methoxypropionate.

[0037] Example 5: Referring to Example 1, the hyperbranched oligomer is a hyperbranched oligomer with six to twelve acryloyloxy functional groups. The modified polybutadiene oligomer is at least one of epoxidized polybutadiene oligomers, carboxyl-terminated polybutadiene oligomers, and hydroxyl-terminated polybutadiene oligomers, or a mixture thereof. The main structure of the fluorine-modified calixarene oligomer is a calix[4-8]arene structure, and the para-position structure of the phenol ring of the fluorine-modified calixarene oligomer is a perfluoroalkyl group, and the structure of the perfluoroalkyl group is (-CF2)n-CF 3， n=1-6. The active diluent containing four to eight polymerizable functional groups is at least one of dipentaerythritol penta / hexaacrylate (hexafunctional accounts for 55-100%), ethoxylated dipentaerythritol hexaacrylate, caprolactone dipentaerythritol hexaacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol tetraacrylate, and tripentaerythritol octaacrylate, or a mixture thereof. The acrylic resin is a polyacrylic acid block copolymer, and the characteristic functional groups include at least one of cyclohexyl, phenyl, epoxy, acryloxy, cyclopentadienyl, oxetane, dicyclopentyl, and naphthyl in addition to carboxyl. The epoxy resin is at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, o-cresol epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, maleimide epoxy resin, and hydantoin epoxy resin, or a mixture thereof. The leveling agent is at least one of an organic silicon leveling agent, an acrylate leveling agent, and a fluorocarbon leveling agent, or a mixture of several thereof; the curing accelerator is one of tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, nadic anhydride, trimellitic anhydride, anionic curing accelerator, maleopimaric anhydride, 2-methylimidazole, 2-phenylimidazole, and tetramethyl sulfoxide, or a mixture of several thereof; the polymerization inhibitor is at least one of tert-butylphenol, tert-butylphenol, diethylhydroxylamine, and piperidinol oxide, or a mixture of several thereof; the silane coupling agent is γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, (2-aminoethyl)aminomethyltrimethoxy The invention comprises at least one or a mixture of silane, γ-isocyanate propyl trimethoxy silane, γ-isocyanate propyl triethoxy silane, γ-mercaptopropyl trimethoxy silane, γ-mercaptopropyl triethoxy silane, 3-glycidoxypropyl trimethoxy silane, 3-glycidoxypropyl triethoxy silane, and β-(3,4-epoxycyclohexyl)ethyl trimethoxy silane; the antioxidant is at least one or a mixture of antioxidants such as aromatic amines, hindered phenols, pentaerythritol tetrapropionate, phosphites, thioethers, etc.; the electronic grade organic solvent is one or a mixture of solvents such as propylene glycol methyl ether, propylene glycol methyl ether acetate, diethylene glycol methyl ethyl ether, 3-methoxypropionate methyl ester, propylene glycol diacetate, 3-methoxybutyl acetate, propylene glycol monoethyl ether, diethylene glycol dimethyl ether, methyl N-amyl ketone, methyl isobutyl ketone, etc.

[0038] Comparative Example 1: Referring to the formula of Example 1, the epoxidized polybutadiene oligomer is replaced by an epoxidized polyester polymer, the fluorinated modified calixarene oligomer is replaced by 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene which also has multiple benzene ring structures, and the proportions of other ingredients remain unchanged.

[0039] Example 6: A method for preparing an OC transparent composition for a CF substrate having both low hygroscopicity and low dielectric constant, comprising the following steps: taking hyperbranched oligomers, modified polybutadiene oligomers, fluorine-modified calixarene oligomers, active diluents containing four to eight polymerizable functional groups, acrylic resins, epoxy resins, leveling agents, silane coupling agents, curing accelerators, inhibitors, antioxidants, and electronic-grade organic solvents according to the formula of Example 1 and mixing them evenly to obtain a finished product.

[0040] Example 7: A method for preparing an OC transparent composition for a CF substrate having both low hygroscopicity and low dielectric constant, comprising the following steps: taking hyperbranched oligomers, modified polybutadiene oligomers, fluorine-modified calixarene oligomers, active diluents containing four to eight polymerizable functional groups, acrylic resins, epoxy resins, leveling agents, silane coupling agents, curing accelerators, inhibitors, antioxidants, and 50% of electronic-grade organic solvents according to the formula of Example 2 and mixing them evenly; using a high-speed disperser to disperse them during mixing, first dispersing them at a speed of 1000 rpm for 10 minutes, then adding the remaining 50% of the electronic-grade organic solvent and dispersing them at 1000 rpm for 3 minutes and mixing them evenly to obtain the finished product.

[0041] Example 8: A method for preparing an OC transparent composition for a CF substrate having both low hygroscopicity and low dielectric constant, comprising the following steps: taking hyperbranched oligomers, modified polybutadiene oligomers, fluorine-modified calixarene oligomers, active diluents containing four to eight polymerizable functional groups, acrylic resins, epoxy resins, leveling agents, silane coupling agents, curing accelerators, inhibitors, antioxidants, and 20% of electronic-grade organic solvents according to the formula of Example 3 and mixing them evenly; using a high-speed disperser to disperse them during mixing, first dispersing them at a speed of 1200 rpm for 12 minutes, then adding the remaining 80% of the electronic-grade organic solvent and dispersing them at 1200 rpm for 4 minutes and mixing them evenly to obtain the finished product.

[0042] Example 9: A method for preparing an OC transparent composition for a CF substrate having both low hygroscopicity and low dielectric constant, comprising the following steps: taking hyperbranched oligomers, modified polybutadiene oligomers, fluorine-modified calixarene oligomers, active diluents containing four to eight polymerizable functional groups, acrylic resins, epoxy resins, leveling agents, silane coupling agents, curing accelerators, inhibitors, antioxidants, and 70% electronic-grade organic solvents according to the formula of Example 4 and mixing them evenly; using a high-speed disperser to disperse them during mixing, first dispersing them at a speed of 1500 rpm for 15 minutes, then adding the remaining 30% of the electronic-grade organic solvent and dispersing them at 1500 rpm for 5 minutes and mixing them evenly to obtain the finished product.

[0043] Comparative Example 2: Referring to Example 6, hyperbranched oligomers, epoxidized polyester polymers, 9,9-bis[4-(2-acryloxyethoxy)phenyl]fluorene, an active diluent containing four to eight polymerizable functional groups, acrylic resin, epoxy resin, leveling agent, silane coupling agent, curing accelerator, inhibitor, antioxidant, and electronic grade organic solvent are taken according to the formula of Comparative Example 1 and mixed evenly to obtain a finished product.

[0044] The formulations of Examples 6 to 9 and the formulation of Comparative Example 2 were respectively spin-coated on a common glass substrate and a CF substrate using a spin coater at a rotation speed of 300 to 450 rpm. After the VCD was evacuated, it was placed on a baking plate at 90 to 100°C for 90 to 120 seconds, and then placed in an oven at 230°C for 25 minutes to obtain an OC coating. The film thickness of the OC coating was controlled to be 1.3±0.05 um by the rotation speed range of the spin coating.

[0045] Table 1 Main performance test results of OC coating on ordinary glass substrate

[0046]

[0047] Table 2 Main performance test results of OC coating on CF substrate

[0048]

[0049] Among them, the test conditions, methods and judgment criteria of each test item are as follows:

[0050] 1. Hardness test: Use a fully automatic pencil hardness tester, model ZJ-3086, using the standard GB / T6739-2006. Each sample is tested three times. The judgment standard is from 6B-BH-6H, and the hardness gradually increases.

[0051] 2. Dielectric constant test: Dielectric constant meter.

[0052] 3. Voltage holding rate test: The test equipment is Espec SU-242 VHR test equipment, which records the VHR value of 5V-60Hz-60℃. The higher the VHR value, the smaller the power loss and the smaller the impact on the normal deflection of the liquid crystal.

[0053] 4. Heat resistance test: The test equipment is TG 8121Thermo Plus EVO2. About 10g of OC coating is weighed. The temperature is raised from 25 to 400℃ at 10℃ / min. The temperature of 5% thermal weight loss is recorded.

[0054] 5. Hygroscopicity test method and equipment: prepare a common glass substrate of size 10cm×9cm and coated with 2.5um cured coating of each embodiment, soak it in water for 1 hour and then blow it dry for testing. Use Vacuum Measuring System GCV2000, set the bottom pressure to 0.003torr, fix the initial pressure to 700Torr, first test the time of empty glass to bottom pressure, then test the time of sample to bottom pressure, and use the difference ΔT between the two as the judgment standard. The smaller ΔT is, the lower the hygroscopicity is.

[0055] 6. Contact angle was not tested: It was mainly used to test the coating properties of PI liquid and the hydrophobicity test (NMP contact angle): KYOWRDWC-MC4, which tests the contact angle of NMP on the cured coating. The smaller the angle, the more beneficial it is for PI liquid coating. The larger the contact angle of H2O, the better the hydrophobicity.

[0056] 7. Degree of planarization (DOP) test: Use a film thickness meter to measure the difference in film thickness of the CF substrate before and after applying the OC coating, and calculate the percentage of the film thickness difference to the film thickness before applying the OC coating. The higher the DOP, the better the planarization ability.

[0057] 8. For shielding test, a CF substrate with an OC coating was prepared, and 100 ul of NMP was dropped on the substrate again and sealed and covered. The substrate was heated at 180°C for 15 minutes, and the substrate was rinsed to obtain the rinsing solution. The absorbance of the rinsing solution at 305 nm was tested with a UV spectrophotometer.

[0058] 9. Contrast test: The test equipment used is CONTRAST TESTERCT-1 produced by TSUBOSAKA ELECTRIC, and the light source is full-band.

[0059] From the test results of Tables 1 and 2 above, it can be seen that the actual solid content (excluding the content of organic solvent) of the formulation of Example 6 is only 10%, but the content of hyperbranched oligomers is high and the double bond content is high, which improves the crosslinking density of the system and maintains good hardness and heat resistance of the coating. Although there are more modified polybutadiene oligomers and less fluorinated calixarene oligomers, the overall content of the two is high, giving the coating excellent low dielectric properties and low hygroscopicity; the solid content of the formulation of Example 7 is 30%, and nearly half of the solid content is active diluent, and the viscosity of the entire composition will not be too large. A large amount of active diluent can react and crosslink with hyperbranched oligomers well, ensuring the high hardness and high heat resistance of the coating, and the flattening performance is not affected. The content of modified polybutadiene oligomers and fluorinated calixarene oligomers is in a relatively suitable ratio range, and the two can form a good host-guest surrounding structure, so that the OC coating obtains a low dielectric constant and low hygroscopicity. In the formula of Example 8, due to the increase in the content of epoxy resin, acrylic resin and curing accelerator, the thermal curing reaction plays a leading role, and the heat resistance of the whole system is greatly improved. At the same time, the content of modified polybutadiene oligomer and fluorine-modified calixarene oligomer is in a relatively suitable ratio range, giving the coating a low dielectric constant and low hygroscopicity. In the formula of Example 9, the content of acrylic resin is relatively high, and the carboxyl, epoxy, double bond and other groups react to reach a relatively more compatible state. At the same time, the functional group naphthyl in the acrylic resin has a spatial barrier effect, which improves the low hygroscopicity of the coating. In addition, the addition of modified polybutadiene oligomer and fluorine-modified calixarene oligomer makes the hygroscopicity and dielectric constant of the whole coating reach satisfactory results. In the formula of comparative example 2, since the epoxidized polybutadiene oligomer is replaced by an epoxidized polyester polymer, and the fluorine-modified calixarene oligomer is replaced by 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, although most of the properties of the entire coating are good, the electrical properties such as hygroscopicity and dielectric constant are not good. In general, Examples 6 to 9 are all added with modified polybutadiene oligomers and fluorine-modified calixarene oligomers, and the appropriate compatibility with other raw materials. The coatings prepared by the corresponding OC transparent compositions not only maintain the high hardness, high thermal stability, high flattening ability, high barrier properties and other properties of the transparent protective composition OC coating for CF substrates compared with the current mainstream products on the market, but also make the OC coating have excellent low hygroscopicity and low dielectric constant, greatly reducing the energy consumption in the flat panel display box forming process, broadening the application range of the material in large-size, high-speed and high-frequency LCD display screens, and have broad application prospects.

[0060] The described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. An OC transparent composition for CF substrates having both low hygroscopicity and low dielectric constant, characterized in that: The invention comprises the following raw materials in percentage by mass: 1-5% of hyperbranched oligomer, 1-5% of modified polybutadiene oligomer, 0.01-3% of fluorine-modified calixarene oligomer, 1-14% of active diluent containing four to eight polymerizable functional groups, 1-10% of acrylic resin, 0.01-5% of epoxy resin, 0.2-0.5% of leveling agent, 0.1-5% of silane coupling agent, 0.1-5% of curing accelerator, 0.01-0.2% of polymerization inhibitor, 0.01-0.2% of antioxidant and 70-90% of electronic grade organic solvent.

2. The OC transparent composition for CF substrates having both low hygroscopicity and low dielectric constant according to claim 1, characterized in that: The hyperbranched oligomer is a hyperbranched oligomer having six to twelve acryloyloxy functional groups.

3. The OC transparent composition for CF substrates having both low hygroscopicity and low dielectric constant according to claim 1, characterized in that: The modified polybutadiene oligomer is at least one of epoxidized polybutadiene oligomer, carboxyl-terminated polybutadiene oligomer and hydroxyl-terminated polybutadiene oligomer or a mixture of several of them.

4. The OC transparent composition for CF substrates having both low hygroscopicity and low dielectric constant according to claim 1, characterized in that: The main structure of the fluorine-modified calixarene oligomer is a calix[4-8]arene structure, the para-position structure of the phenol ring of the fluorine-modified calixarene oligomer is a perfluoroalkyl group, and the structure of the perfluoroalkyl group is (-CF2)n-CF 3， n=1~6.

5. The OC transparent composition for CF substrates having both low hygroscopicity and low dielectric constant according to claim 1, characterized in that: The active diluent containing four to eight polymerizable functional groups is at least one of dipentaerythritol penta / hexaacrylate (hexafunctional accounts for 55-100%), ethoxylated dipentaerythritol hexaacrylate, caprolactone dipentaerythritol hexaacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol tetraacrylate, and tripentaerythritol octaacrylate, or a mixture of several thereof.

6. The OC transparent composition for CF substrates having both low hygroscopicity and low dielectric constant according to claim 1, characterized in that: The acrylic resin is a polyacrylic acid block copolymer, and its characteristic functional groups include at least one of cyclohexyl, phenyl, epoxy, acryloxy, cyclopentadienyl, oxetane, dicyclopentyl and naphthyl in addition to carboxyl.

7. The OC transparent composition for CF substrates having both low hygroscopicity and low dielectric constant according to claim 1, characterized in that: The epoxy resin is at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, o-cresol epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, maleimide epoxy resin, hydantoin epoxy resin or a mixture of several thereof.

8. The OC transparent composition for CF substrates having both low hygroscopicity and low dielectric constant according to claim 1, characterized in that: The leveling agent is at least one of an organic silicon leveling agent, an acrylate leveling agent, and a fluorocarbon leveling agent, or a mixture of several thereof; The curing accelerator is one or a mixture of tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, nadic anhydride, trimellitic anhydride, anionic curing accelerator, maleopimaric anhydride, 2-methylimidazole, 2-phenylimidazole, tetramethyl sulfoxide; The polymerization inhibitor is at least one of tert-butylphenol, tert-butylphenol, diethylhydroxylamine, and piperidinol oxide, or a mixture of several thereof; The silane coupling agent is at least one of γ-aminopropyl trimethoxysilane, N-β-aminoethyl-γ-aminopropyl trimethoxysilane, N-phenyl-γ-aminopropyl trimethoxysilane, 3-glycidyloxypropyl trimethoxysilane, 3-glycidyloxypropyl triethoxysilane, (2-aminoethyl)aminomethyl trimethoxysilane, γ-isocyanate propyl trimethoxysilane, γ-isocyanate propyl triethoxysilane, γ-mercaptopropyl trimethoxysilane, γ-mercaptopropyl triethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl triethoxysilane, and β-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, or a mixture of several thereof; The antioxidant is at least one or a mixture of aromatic amines, hindered phenols, pentaerythritol tetrapropionate, phosphites, thioethers and the like; The electronic grade organic solvent is one or a mixture of solvents such as propylene glycol methyl ether, propylene glycol methyl ether acetate, diethylene glycol methyl ethyl ether, 3-methoxypropionic acid methyl ester, propylene glycol diacetate, 3-methoxybutyl acetate, propylene glycol monoethyl ether, diethylene glycol dimethyl ether, methyl N-amyl ketone, and methyl isobutyl ketone.

9. A method for preparing an OC transparent composition for a CF substrate having both low hygroscopicity and low dielectric constant as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: According to the formula, hyperbranched oligomers, modified polybutadiene oligomers, fluorine-modified calixarene oligomers, active diluents containing four to eight polymerizable functional groups, acrylic resins, epoxy resins, leveling agents, silane coupling agents, curing accelerators, polymerization inhibitors, antioxidants, and electronic-grade organic solvents are taken and mixed uniformly to obtain a finished product.

10. The method for preparing the OC transparent composition for CF substrate having both low hygroscopicity and low dielectric constant according to claim 9, characterized in that: The first step is to evenly mix part of the electronic grade organic solvent and the other raw materials, and the second step is to add the remaining electronic grade organic solvent and mix them evenly; a high-speed disperser is used for dispersion during mixing, and the first step is to disperse at a rotation speed of 1000-1500rpm for 10-15min, and the second step is to disperse at 1000-1500rpm for 3-5min.

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