An oc transparent composition for cf substrate having low moisture absorption and low dielectric constant

Abstract

This invention discloses an OC transparent composition for CF substrates that combines low hygroscopicity and low dielectric constant, comprising the following raw materials in weight percentages: 1-5% hyperbranched oligomer, 1-5% modified polybutadiene oligomer, 0.01-3% fluorinated modified calixarene oligomer, 1-14% reactive diluent containing four to eight polymerizable functional groups, 1-10% acrylic resin, 0.01-5% epoxy resin, 0.2-0.5% leveling agent, 0.1-5% silane coupling agent, 0.1-5% curing accelerator, 0.01-0.2% polymerization inhibitor, 0.01-0.2% antioxidant, and 70-90% electronic grade organic solvent. This invention not only maintains the main properties of the OC coating for transparent protective composition of CF substrate, such as high hardness, high thermal stability, high planarization ability, and high barrier properties, but also gives the OC coating excellent low moisture absorption and low dielectric constant, which greatly reduces energy consumption in the flat panel display cell assembly process and broadens the application range of OC materials in large-size, high-speed, high-frequency LCD displays.

Description

Technical Field

[0001] This invention relates to the field of photoresists, and more particularly to an OC transparent composition for CF substrates that combines low moisture absorption and low dielectric constant. Background Technology

[0002] Traditional LCD displays, also known as liquid crystal displays, are flat, ultra-thin display devices. They are mainly composed of an array substrate, a CF substrate, liquid crystal, and polarizers. LCD displays have very low power consumption, making them highly popular. In the entire LCD display manufacturing process, the OC coating mainly plays a role in protecting and flattening the CF substrate. Specifically, it can prevent the leakage of trace amounts of tiny molecules or metal ions from materials such as RGB and BM, thus protecting the liquid crystal. At the same time, it flattens the interlayer thickness differences formed in each RGB process, so as to adapt to subsequent processes such as PI liquid coating and liquid crystal drop-in.

[0003] With the improvement of living standards and the continuous construction of high-generation production lines, LCD displays are developing towards ultra-large size, high precision, and high frequency, and their application scope has expanded to ultra-large TVs, advertising screens, touch screens, and other devices. This has also placed higher demands on the formulation innovation of electronic chemicals used in production. Currently, OC materials used in LCDs are mainly thermosetting, and while requirements for them include conventional flatness, heat resistance, and barrier properties, little attention has been paid to their hygroscopicity and electrical properties. In reality, when the panel size is too large, achieving the target vacuum level required for cell assembly consumes more energy and time, highlighting the poor hygroscopicity of OC materials. To save energy and costs and improve economic efficiency, it is necessary to improve the hygroscopicity resistance of OC materials. Furthermore, with the increasing demands for visual experience, screens are developing towards higher frequencies and speeds. Coupled with the booming development of 5G networks, even higher requirements have been placed on the electrical properties of the materials used, demanding low dielectric constants and high voltage retention rates.

[0004] Existing OC transparent compositions for CF substrates and their coating processes have the following disadvantages:

[0005] 1. Currently, the production of standard-sized displays does not have high requirements for the low hygroscopicity of materials. However, in the process of producing increasingly larger substrates, it has been found that the larger the panel size, the greater the energy consumption and time required in the vacuuming stage before cell assembly, resulting in a significant reduction in economic efficiency. Therefore, the problem of poor hygroscopicity of conventional OC materials has become prominent, which limits the development of OC materials in the application of larger-sized panels. At the same time, if the OC film has poor hygroscopicity during the washing process, the polymer is more susceptible to moisture, which will cause the dielectric loss of the material to increase generally over a wide frequency range.

[0006] 2. The dielectric constant of some photoresist materials, such as RGB, is generally around 4-5. Different products require different semiconductor materials. However, if the dielectric constant of the OC coating material, which is closer to the liquid crystal, is high, it will adversely affect the operation of the liquid crystal after it is powered on, thus affecting the lifespan of the display and the viewing comfort. The curing agents commonly used in the conventional existing processes of OC materials are phenolic epoxy resins, some of which add anhydride curing agents. The cured products often contain hydroxyl groups and residual carboxyl groups. Some products also add a certain amount of polyurethane acrylate, which can improve the yellowing of the entire system, but the introduction of amide bonds also increases the polarity of the cured product to a certain extent, resulting in a higher dielectric constant. Ultimately, this limits the application of these OC coating materials in the range of high-frequency and high-speed line communication.

[0007] 3. Existing technical documents: JP-A-9-263560 discloses a calixarene compound as a photocurable composition. This compound contains unsaturated double bonds and requires the addition of a photoinitiator for curing, which is different from the thermosetting process used in this invention. If this compound is added to this solution, a hard film still needs to be baked after curing, which is relatively complicated. CN116199559A also relates to a low dielectric and high heat-resistant calixarene resin and its preparation method and application. It prepares calixarene containing unsaturated double bonds, which also requires the addition of a photoinitiator for curing and does 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 fluorinated calix (4) aromatic resins and polybutadiene structures in the field of CF substrates.

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

[0009] The purpose of this invention is to provide an OC transparent composition for CF substrates that has both low moisture absorption and low dielectric constant.

[0010] The innovation of this invention lies in maintaining the high hardness, high thermal stability, high planarization capability, and high barrier properties of the OC coating in the transparent protective composition for CF substrates, while simultaneously enabling the OC coating to possess excellent low moisture absorption and a low dielectric constant, thus broadening the application range of the material in large-size, high-speed, high-frequency LCD displays. To achieve the above-mentioned objectives, the technical solution of this invention is as follows:

[0011] An OC transparent composition for CF substrates, possessing both low hygroscopicity and low dielectric constant, comprises the following raw materials in weight percentages: 1-5% hyperbranched oligomer, 1-5% modified polybutadiene oligomer, 0.01-3% fluorinated modified calixarene oligomer, 1-14% reactive diluent containing four to eight polymerizable functional groups, 1-10% acrylic resin, 0.01-5% epoxy resin, 0.2-0.5% leveling agent, 0.1-5% silane coupling agent, 0.1-5% curing accelerator, 0.01-0.2% polymerization inhibitor, 0.01-0.2% antioxidant, and 70-90% electronic grade organic solvent.

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

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

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

[0015] Further, the reactive diluent containing four to eight polymerizable functional groups is at least one or a mixture of several of the following: dipentaerythritol penta / hexaacrylate (hexafunctional group content 55-100%), ethoxylated dipentaerythritol hexaacrylate, caprolactone-modified dipentaerythritol hexaacrylate, bis(trimethylolpropane) tetraacrylate, pentaerythritol tetraacrylate, and tripentaerythritol octaacrylate.

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

[0017] Further, the epoxy resin is at least one or a mixture of several of the following: 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.

[0018] Furthermore, the leveling agent is at least one or a mixture of several of the following: silicone leveling agent, acrylate leveling agent, and fluorocarbon leveling agent;

[0019] The curing accelerator is one or a mixture of several of the following: tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, nadic anhydride, trimellitic anhydride, anionic curing accelerator, maleic anhydride, 2-methylimidazole, 2-phenylimidazole, and tetramethyl sulfoxide.

[0020] The polymerization inhibitor is at least one or a mixture of several of the following: tert-butylphenol, diethylhydroxylamine, and piperidinol oxide.

[0021] The silane coupling agent is at least one or a mixture of several of the following: γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, 3-glycidyl ether oxypropyltrimethoxysilane, 3-glycidyl ether oxypropyltriethoxysilane, (2-aminoethyl)aminomethyltrimethoxysilane, γ-isocyanate propyltrimethoxysilane, γ-isocyanate propyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0022] The antioxidant is at least one or a mixture of several antioxidants such as aromatic amines, hindered phenols, pentaerythritol tetrapropionate, phosphites, and thioethers.

[0023] The electronic-grade organic solvent is one or a mixture of several solvents selected from propylene glycol methyl ether, propylene glycol methyl ether acetate, diethylene glycol methyl ethyl ether, methyl 3-methoxypropionate, propylene glycol diacetate, 3-methoxybutylacetate, propylene glycol monoethyl ether, diethylene glycol dimethyl ether, methyl N-pentyl ketone, methyl isobutyl ketone, etc.

[0024] A method for preparing an OC transparent composition for CF substrates that combines low moisture absorption and low dielectric constant includes the following steps:

[0025] Take hyperbranched oligomers, modified polybutadiene oligomers, fluorinated calixarene oligomers, reactive 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 according to the formula and mix them evenly to obtain the finished product.

[0026] Further, in the first step, a portion of the electronic-grade organic solvent and the remaining raw materials are mixed evenly. In the second step, the remaining electronic-grade organic solvent is added and mixed evenly. During the mixing, a high-speed disperser is used. In the first step, the dispersion is carried out at a speed of 1000-1500 rpm for 10-15 minutes, and in the second step, the dispersion is carried out at a speed of 1000-1500 rpm for 3-5 minutes.

[0027] The beneficial effects of this invention are:

[0028] 1. This invention adds fluorinated calixarane oligomers to the material. These oligomers have multiple benzene rings, and the resulting bowl-shaped structure can block the entry of water. The combination of multiple benzene rings and conjugated structures not only maintains the good heat resistance of the cured product but also acts as a hydrophobic agent. In addition, the introduction of fluorocarbon structures on the side chains allows fluorine at the end of the cured film to migrate to the coating surface, which can further reduce the surface energy and hygroscopicity of the coating.

[0029] 2. The modified polybutadiene oligomer in this invention contains a large number of non-polar polybutadiene structures. Introducing this structure not only maintains the polymer's excellent hydrophobic properties but also reduces the material's dielectric constant. Simultaneously, it reduces some of the extremely high brittleness caused by fluorinated calixarene and hyperbranched oligomers, dissipating some stress. This ensures that the OC material maintains high hardness while also possessing flexibility and heat resistance. The most prominent advantage is its non-polar structure, which allows it to form a host-guest enclosed structure with calixarene, increasing the crosslinking density of the cured material, reducing the free volume between molecules, facilitating the exclusion or entry of small molecules, improving the barrier effect of the OC coating material, effectively reducing the material's hygroscopicity, and further lowering the dielectric constant.

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

[0031] 4. This invention not only maintains the main properties of the OC coating of the transparent protective composition for CF substrates, such as high hardness, high thermal stability, high planarization ability, and high barrier properties, but also gives the OC coating excellent low moisture absorption and low dielectric constant, which greatly reduces energy consumption in the flat panel display cell assembly process and broadens the application range of the material in large-size, high-speed, high-frequency LCD displays. Detailed Implementation

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

[0033] Example 1: An OC transparent composition for CF substrates with both low hygroscopicity and low dielectric constant, comprising the following raw materials in weight percentages: 4% hyperbranched oligomer, 3.56% modified polybutadiene oligomer, 0.01% fluorinated modified calixarene oligomer, 1% reactive 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% polymerization inhibitor, 0.01% antioxidant, and 90% electronic-grade organic solvent. The hyperbranched oligomer is a hyperbranched oligomer with six to twelve acryloyloxy functional groups. The modified polybutadiene oligomer is an epoxidized polybutadiene oligomer. The main structure of the fluorinated calixarene oligomer is a calix[4-8]arene structure. The para-position structure of the phenol ring in the fluorinated calixarene oligomer is a perfluoroalkyl group, and the structure of the perfluoroalkyl group is (-CF2)n-CF3, where n=1. The reactive diluent containing four to eight polymerizable functional groups is dipentaerythritol penta / hexaacrylate (hexafunctional group accounts for 55%). The acrylic resin is a polyacrylic acid block copolymer, and the characteristic functional groups include cyclohexyl groups in addition to carboxyl groups. The epoxy resin is bisphenol A epoxy resin. The leveling agent is an organosilicon leveling agent; the curing accelerator is tetrahydrophthalic anhydride; the polymerization 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] Example 2: An OC transparent composition for CF substrates with both low hygroscopicity and low dielectric constant, comprising the following raw materials in weight percentages: 1% hyperbranched oligomer, 2% modified polybutadiene oligomer, 1% fluorinated modified calixarene oligomer, 14% reactive 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% polymerization 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 fluorinated calixarene oligomer is a calix[4-8]arene structure. The para-position structure of the phenol ring in the fluorinated calixarene oligomer is a perfluoroalkyl group, and the structure of the perfluoroalkyl group is (-CF2)n-CF3, n=4. The reactive diluent containing four to eight polymerizable functional groups is dipentaerythritol penta / hexaacrylate (hexafunctional group accounts for 80%). The acrylic resin is a polyacrylic acid block copolymer, and the characteristic functional groups include dicyclopentyl groups in addition to carboxyl groups. The epoxy resin is bisphenol F epoxy resin. The leveling agent is an acrylate leveling agent; the curing accelerator is methyltetrahydrophthalic anhydride; the polymerization 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] Example 3: An OC transparent composition for CF substrates with both low hygroscopicity and low dielectric constant, comprising the following raw materials in weight percentages: 2% hyperbranched oligomer, 5% modified polybutadiene oligomer, 3% fluorinated modified calixarene oligomer, 2% reactive 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% polymerization inhibitor, 0.2% antioxidant, and 72% electronic-grade organic solvent. The hyperbranched oligomer is a hyperbranched oligomer with six to twelve acryloyloxy functional groups. The modified polybutadiene oligomer is a hydroxyl-terminated polybutadiene oligomer. The main structure of the fluorinated calixarene oligomer is a calix[4-8]arene structure. The para-position structure of the phenol ring in the fluorinated calixarene oligomer is a perfluoroalkyl group, and the structure of the perfluoroalkyl group is (-CF2)n-CF3, n=6. The reactive diluent containing four to eight polymerizable functional groups is pentaerythritol penta / hexaacrylate (hexafunctionality 100%). The acrylic resin is a polyacrylic acid block copolymer, and the characteristic functional groups include acryloyloxy groups 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 polymerization inhibitor is diethyl hydroxylamine; the silane coupling agent is N-phenyl-γ-aminopropyltrimethoxysilane; the antioxidant is pentaerythritol tetrapropionate; and the electronic grade organic solvent is diethylene glycol methyl ethyl ether.

[0036] Example 4: An OC transparent composition for CF substrates with both low hygroscopicity and low dielectric constant, comprising the following raw materials in weight percentages: 5% hyperbranched oligomer, 1% modified polybutadiene oligomer, 0.02% fluorinated modified calixarene oligomer, 3% reactive 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% polymerization inhibitor, 0.04% antioxidant, and 80% electronic-grade organic solvent. The hyperbranched oligomer is a hyperbranched oligomer with six to twelve acryloyloxy functional groups. The modified polybutadiene oligomer is an epoxidized polybutadiene oligomer. The main structure of the fluorinated calixarene oligomer is a calix[4-8]arene structure. The para-position structure of the phenol ring in the fluorinated calixarene oligomer is a perfluoroalkyl group, and the structure of the perfluoroalkyl group is (-CF2)n-CF3, n=6. The reactive diluent containing four to eight polymerizable functional groups is ethoxylated pentaerythritol hexaacrylate. The acrylic resin is a polyacrylic acid block copolymer, and the characteristic functional groups include naphthyl groups in addition to carboxyl groups. The epoxy resin is an alicyclic epoxy resin. The leveling agent is an organosilicon leveling agent; the curing accelerator is nadic anhydride; the polymerization inhibitor is piperidinol oxide; the silane coupling agent is 3-glycidyl etheroxypropyltrimethoxysilane; the antioxidant is 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 or a mixture of several of the following: epoxidized polybutadiene oligomer, carboxyl-terminated polybutadiene oligomer, and hydroxyl-terminated polybutadiene oligomer. The main structure of the fluorinated calixarene oligomer is a calix[4-8]arene structure, the para-position structure of the phenol ring in the fluorinated calixarene oligomer is a perfluoroalkyl group, and the structure of the perfluoroalkyl group is (-CF2)n-CF 3， n = 1–6. The reactive diluent containing four to eight polymerizable functional groups is at least one or a mixture of several of the following: dipentaerythritol penta / hexaacrylate (hexafunctional group 55–100%), ethoxylated dipentaerythritol hexaacrylate, caprolactone-modified dipentaerythritol hexaacrylate, bis(trimethylolpropane)tetraacrylate, pentaerythritol tetraacrylate, and tripentaerythritol octaacrylate. The acrylic resin is a polyacrylic acid block copolymer, and its characteristic functional groups, in addition to carboxyl groups, include at least one of cyclohexyl, phenyl, epoxy, acryloyloxy, cyclopentadienyl, oxetyl, dicyclopentyl, and naphthyl groups. The epoxy resin is at least one or a mixture of several of the following: bisphenol A epoxy resin, bisphenol F epoxy resin, o-cresolaldehyde epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, maleimide epoxy resin, and hydantoin epoxy resin. The leveling agent is at least one or a mixture of several selected from silicone leveling agents, acrylate leveling agents, and fluorocarbon leveling agents; the curing accelerator is at least one or a mixture of several selected from tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, nadic anhydride, trimellitic anhydride, anionic curing accelerator, maleic anhydride, 2-methylimidazole, 2-phenylimidazole, and tetramethyl sulfoxide; the polymerization inhibitor is at least one or a mixture of several selected from tert-butylphenol, tert-butylphenol, diethylhydroxylamine, and piperidinol oxide; the silane coupling agent is at least one or a mixture of several selected from γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, 3-glycidyl etheroxypropyltrimethoxysilane, 3-glycidyl etheroxypropyltriethoxysilane, and (2-aminoethyl)aminomethyltrimethoxysilane. The formula includes at least one or a mixture of several of the following: silane, γ-isocyanate propyltrimethoxysilane, γ-isocyanate propyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropyltriethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; the antioxidant is at least one or a mixture of several of the following: aromatic amine, hindered phenol, pentaerythritol tetrapropionate, phosphite, thioethers, etc.; and the electronic-grade organic solvent is at least one or a mixture of several of the following: propylene glycol methyl ether, propylene glycol methyl ether acetate, diethylene glycol methyl ethyl ether, methyl 3-methoxypropionate, propylene glycol diacetate, 3-methoxybutyl acetate, propylene glycol monoethyl ether, diethylene glycol dimethyl ether, methyl N-pentyl ketone, methyl isobutyl ketone, etc.

[0038] Comparative Example 1: Referring to the formulation of Example 1, the epoxidized polybutadiene oligomer was replaced with an epoxidized polyester polymer, and the fluorinated calixarene oligomer was replaced with 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, which also has multiple benzene ring structures, while the proportions of the remaining components remained unchanged.

[0039] Example 6: A method for preparing an OC transparent composition for CF substrates with both low hygroscopicity and low dielectric constant, comprising the following steps: taking hyperbranched oligomer, modified polybutadiene oligomer, fluorinated calixarene oligomer, reactive diluent containing four to eight polymerizable functional groups, acrylic resin, epoxy resin, leveling agent, silane coupling agent, curing accelerator, polymerization inhibitor, antioxidant, and electronic grade organic solvent according to the formulation of Example 1, and mixing them evenly to obtain the finished product.

[0040] Example 7: A method for preparing an OC transparent composition for CF substrates with both low hygroscopicity and low dielectric constant, comprising the following steps: taking hyperbranched oligomer, modified polybutadiene oligomer, fluorinated calixarene oligomer, reactive diluent containing four to eight polymerizable functional groups, acrylic resin, epoxy resin, leveling agent, silane coupling agent, curing accelerator, polymerization inhibitor, antioxidant, and 50% electronic-grade organic solvent according to the formulation of Example 2, and mixing them evenly. During mixing, the mixture is dispersed using a high-speed disperser. First, it is dispersed at 1000 rpm for 10 min, and then the remaining 50% electronic-grade organic solvent is added and dispersed at 1000 rpm for 3 min. The mixture is then mixed evenly to obtain the finished product.

[0041] Example 8: A method for preparing an OC transparent composition for CF substrates with both low hygroscopicity and low dielectric constant, comprising the following steps: taking hyperbranched oligomer, modified polybutadiene oligomer, fluorinated calixarene oligomer, reactive diluent containing four to eight polymerizable functional groups, acrylic resin, epoxy resin, leveling agent, silane coupling agent, curing accelerator, polymerization inhibitor, antioxidant, and 20% electronic-grade organic solvent according to the formulation of Example 3, and mixing them evenly. During mixing, the mixture is dispersed using a high-speed disperser. First, it is dispersed at 1200 rpm for 12 min, and then the remaining 80% electronic-grade organic solvent is added and dispersed at 1200 rpm for 4 min. The mixture is then mixed evenly to obtain the finished product.

[0042] Example 9: A method for preparing an OC transparent composition for CF substrates with both low hygroscopicity and low dielectric constant, comprising the following steps: taking hyperbranched oligomer, modified polybutadiene oligomer, fluorinated calixarene oligomer, reactive diluent containing four to eight polymerizable functional groups, acrylic resin, epoxy resin, leveling agent, silane coupling agent, curing accelerator, polymerization inhibitor, antioxidant, and 70% electronic grade organic solvent according to the formulation of Example 4, and mixing them evenly. During mixing, the mixture is dispersed using a high-speed disperser. First, it is dispersed at 1500 rpm for 15 min, and then the remaining 30% electronic grade organic solvent is added and dispersed at 1500 rpm for 5 min. The mixture is then mixed evenly to obtain the finished product.

[0043] Comparative Example 2: Referring to Example 6, hyperbranched oligomer, epoxidized polyester polymer, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, reactive diluent containing four to eight polymerizable functional groups, acrylic resin, epoxy resin, leveling agent, silane coupling agent, curing accelerator, polymerization inhibitor, antioxidant, and electronic grade organic solvent were taken according to the formulation of Comparative Example 1 and mixed evenly to obtain the finished product.

[0044] The formulations of Examples 6-9 and Comparative Example 2 were spin-coated onto ordinary glass substrates and CF substrates respectively using a spin coater at a speed of 300-450 rpm. After vacuuming using a VCD, the substrates were placed in an oven at 90-100°C for 90-120 seconds, followed by baking in an oven at 230°C for 25 minutes to obtain the OC coating. The film thickness of the OC coating was controlled to be 1.3 ± 0.05 μm by adjusting the spin-coating speed range.

[0045] Table 1. Test results of main performance of OC coating on ordinary glass substrates

[0046]

[0047] Table 2. Test results of main performance of OC coating on CF substrate.

[0048]

[0049] The test conditions, methods, and judgment criteria for each test item are as follows:

[0050] 1. Hardness test: A fully automatic pencil hardness tester, model ZJ-3086, was used, and the standard was GB / T6739-2006. Each sample was tested three times, and the judgment standard was from 6B to BH to 6H, with the hardness gradually increasing.

[0051] 2. Dielectric constant test: Dielectric constant measuring instrument.

[0052] 3. Voltage Hold-up Test: The test equipment is the Espec SU-242 VHR tester. The VHR value is recorded at 5V-60Hz-60℃. The higher the VHR value, the lower 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. Weigh about 10g of OC coating, and heat it from 25 to 400℃ at 10℃ / min. Record the temperature at which 5% thermal weight loss occurs.

[0054] 5. Test method and equipment for hygroscopicity: Prepare ordinary glass substrates measuring 10cm × 9cm with a 2.5µm cured coating from each embodiment. Soak in water for 1 hour, then dry and test. Use a Vacuum Measuring System GCV2000, set the bottom pressure to 0.003 torr, and the initial pressure to 700 torr. First, test the time to reach the bottom pressure for the blank glass, then test the time to reach the bottom pressure for the sample. Use the difference ΔT between the two as the criterion; the smaller ΔT is, the lower the hygroscopicity.

[0055] 6. Contact angle not tested: Mainly for testing the coating properties and hydrophobicity of PI liquid (NMP contact angle): KYOWRDWC-MC4, to test the contact angle of NMP on the cured coating. The smaller the angle, the better the coating of PI liquid. The larger the contact angle of H2O, the better the hydrophobicity.

[0056] 7. Degree of Planarization (DOP) Test: The difference in film thickness of the CF substrate before and after OC coating is measured using a film thickness gauge, and the percentage of the film thickness difference to the film thickness before OC coating is calculated. The higher the DOP, the better the planarization capability.

[0057] 8. Masking test: Prepare a CF substrate with an OC coating, drop 100 μL of NMP onto the substrate again and seal it. Heat at 180°C for 15 min, rinse the substrate to obtain the washing solution, and then use a UV spectrophotometer to measure the absorbance of the washing solution at 305 nm.

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

[0059] As can be seen from the test results in Tables 1 and 2 above, the actual solid content (excluding organic solvents) of the formulation in 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 the good hardness and heat resistance of the coating. Although there is more modified polybutadiene oligomers and less fluorinated calixarene oligomers, the overall content of both is high, which gives the coating excellent low dielectric properties and low hygroscopicity. The solid content of the formulation in Example 7 reaches 30%, and nearly half of the solid content is reactive diluent. The viscosity of the entire composition is not too high. A large amount of reactive diluent can react and crosslink well with hyperbranched oligomers, ensuring the high hardness and high heat resistance of the coating. The planarization performance is not affected. The content of modified polybutadiene oligomers and fluorinated calixarene oligomers is in a relatively suitable ratio range. The two can form a good host-guest enclosed structure, which makes the OC coating obtain a low dielectric constant and low hygroscopicity. In the formulation of Example 8, the increased content of epoxy resin, acrylic resin, and curing accelerator led to a dominant thermosetting reaction, significantly improving the overall heat resistance of the system. Simultaneously, the modified polybutadiene oligomer and fluorinated calixarene oligomer were in a suitable ratio, imparting a low dielectric constant and low hygroscopicity to the coating. In the formulation of Example 9, the higher acrylic resin content resulted in a more compatible reaction between carboxyl, epoxy, and double bond groups. Furthermore, the naphthyl functional group in the acrylic resin exhibited a steric hindrance effect, enhancing the coating's low hygroscopicity. The addition of modified polybutadiene oligomer and fluorinated calixarene oligomer further improved both the hygroscopicity and dielectric constant of the coating. In Comparative Example 2, the epoxidized polybutadiene oligomer was replaced with an epoxidized polyester polymer, and the fluorinated calixarene oligomer was replaced with 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene. Although most of the coating properties were good, the electrical properties, such as hygroscopicity and dielectric constant, were not ideal. Overall, Examples 6-9, through the addition of modified polybutadiene oligomers and fluorinated calixarene oligomers, along with appropriate compatibility with other raw materials, resulted in coatings made from the corresponding OC transparent compositions. Compared with currently commercially available mainstream products, these coatings not only maintain the high hardness, high thermal stability, high planarization ability, and high barrier properties of the OC coating for CF substrates, but also exhibit excellent low hygroscopicity and a low dielectric constant. This significantly reduces energy consumption in the flat panel display cell assembly process, broadens the application range of the material in large-size, high-speed, high-frequency LCD displays, and has broad application prospects.

[0060] The described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. An OC transparent composition for CF substrates that combines low moisture absorption and low dielectric constant, characterized in that, The product comprises the following raw materials by weight percentage: 1-5% hyperbranched oligomers, 1-5% modified polybutadiene oligomers, 0.01-3% fluorinated modified calixarene oligomers, 1-14% reactive diluents containing four to eight polymerizable functional groups, 1-10% acrylic resin, 0.01-5% epoxy resin, 0.2-0.5% leveling agent, 0.1-5% silane coupling agent, 0.1-5% curing accelerator, 0.01-0.2% polymerization inhibitor, 0.01-0.2% antioxidant, and 70-90% electronic grade organic solvents.

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

3. The OC transparent composition for CF substrates with both low moisture absorption 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.

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

5. The OC transparent composition for CF substrates with both low moisture absorption and low dielectric constant according to claim 1, characterized in that, The reactive diluent containing four to eight polymerizable functional groups is at least one of dipentaerythritol penta / hexaacrylate, ethoxylated dipentaerythritol hexaacrylate, caprolactone-modified dipentaerythritol hexaacrylate, bis(trimethylolpropane)tetraacrylate, pentaerythritol tetraacrylate, and tripentaerythritol octaacrylate. The dipentaerythritol penta / hexaacrylate is a monomer mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate, and the mass percentage of dipentaerythritol hexaacrylate in the monomer mixture is 55-100%.

6. The OC transparent composition for CF substrates with both low moisture absorption 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, in addition to carboxyl groups, include at least one of cyclohexyl, phenyl, epoxy, acryloyloxy, cyclopentadienyl, oxetyl, dicyclopentyl, and naphthyl.

7. The OC transparent composition for CF substrates with both low moisture absorption 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, and hydantoin epoxy resin.

8. The OC transparent composition for CF substrates with both low moisture absorption and low dielectric constant according to claim 1, characterized in that, The leveling agent is at least one of silicone leveling agent, acrylate leveling agent, and fluorocarbon leveling agent; The curing accelerator is one or more of tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, nadic anhydride, trimellitic anhydride, anionic curing accelerator, maleic anhydride, 2-methylimidazole, 2-phenylimidazole, and tetramethyl sulfoxide. The polymerization inhibitor is at least one of tert-butylphenol, tert-butylphenol, diethylhydroxylamine, and piperidinol oxide; The silane coupling agent is at least one selected from γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, 3-glycidyl ether oxypropyltrimethoxysilane, 3-glycidyl ether oxypropyltriethoxysilane, (2-aminoethyl)aminomethyltrimethoxysilane, γ-isocyanate propyltrimethoxysilane, γ-isocyanate propyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. The antioxidant is at least one of aromatic amines, hindered phenols, pentaerythritol tetrapropionate, phosphites, and thioether antioxidants. The electronic-grade organic solvent is one of the following: propylene glycol methyl ether, propylene glycol methyl ether acetate, diethylene glycol methyl ethyl ether, methyl 3-methoxypropionate, propylene glycol diacetate, 3-methoxybutylacetate, propylene glycol monoethyl ether, diethylene glycol dimethyl ether, methyl N-pentyl ketone, and methyl isobutyl ketone solvent.

9. A method for preparing an OC transparent composition for a CF substrate with low hygroscopicity and low dielectric constant as described in any one of claims 1 to 8, characterized in that, Includes the following steps: Take hyperbranched oligomers, modified polybutadiene oligomers, fluorinated calixarene oligomers, reactive 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 according to the formula and mix them evenly to obtain the finished product.

10. The method for preparing the OC transparent composition for CF substrates with both low hygroscopicity and low dielectric constant according to claim 9, characterized in that, First, mix a portion of the electronic-grade organic solvent with the remaining raw materials evenly. Second, add the remaining electronic-grade organic solvent and mix evenly. During mixing, use a high-speed disperser. First, disperse at 1000-1500 rpm for 10-15 minutes. Second, disperse at 1000-1500 rpm for 3-5 minutes.

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