LCD packaging adhesive and preparation method thereof

Abstract

The invention discloses an LCD packaging adhesive and a preparation method thereof, and the packaging adhesive comprises the following components in parts by weight: 22-60% of modified resin, 7-15% of epoxy resin, 5-9% of a curing agent, 15-25% of a filler, 0.5-1.0% of a photoinitiator, 0.5-1.0% of a thermal initiator, 7-15% of a cross-linking agent, 0.3-0.9% of a polymerization inhibitor, 4-10% of a flexibilizer and 0.7-1.1% of an auxiliary agent. The preparation method specifically comprises the following steps: stirring the modified resin, the epoxy resin and the photoinitiator in a reaction kettle at a stirring speed of 400-800 rpm for 0.5 h, and uniformly mixing to obtain a glue solution; and adding a thermal initiator and a curing agent into the glue solution, stirring for 0.5 h, adding a cross-linking agent, stirring for 0.5 h, adding a filler, a polymerization inhibitor, a flexibilizer and an auxiliary agent, stirring for 0.5 h, and grinding by a three-roller grinder to obtain the LCD packaging glue. The LCD packaging adhesive prepared by the invention has excellent long-term reliability, adhesive property and storage stability, and provides key material guarantee for large-scale application of a liquid crystal display technology.

Description

Technical Field

[0001] This invention relates to an LCD encapsulating adhesive and its preparation method, belonging to the field of materials science and electronic packaging in LCD display technology. Background Technology

[0002] Liquid crystal display (LCD) technology is one of the most rapidly developing high-tech fields of the 21st century. It consists of chips, wires, brackets, conductive adhesives, and encapsulating adhesives. In recent years, with the continuous improvement of LCD manufacturing technology, its luminous efficiency, brightness, and power have been greatly improved. This has placed higher demands on the optical, mechanical, electrical, and heat resistance properties of LCD encapsulation materials. Traditional epoxy resins can no longer fully meet the encapsulation requirements of LCDs.

[0003] Liquid crystal displays (LCDs) have become the mainstream display solution for many consumer electronics products due to their excellent visual performance, low power consumption, thinness, and wide applicability. The device mainly consists of a backlight module and a liquid crystal display panel, where the panel is composed of a color filter (CF) substrate, a thin-film transistor (TFT) array substrate, liquid crystal dielectric, and sealant. The manufacturing process includes array fabrication (forming the TFT array), cell assembly, and module assembly.

[0004] Encapsulating adhesive plays a crucial sealing role in the cell assembly process. Although used in small quantities, it is essential for maintaining the structural integrity and long-term reliability of the panel. Currently, ultraviolet (UV) and thermosetting dual-curing frame adhesives are widely used. These adhesives form a stable network structure through photo-initiated free radical polymerization and thermosetting cross-linking reactions, ensuring bonding strength. To improve long-term reliability, the encapsulating adhesive must possess excellent bonding properties, water resistance, and resistance to damp heat aging to prevent bonding failure or moisture intrusion, ensuring the reliability of the display panel in harsh environments.

[0005] Patent CN 1159625 C discloses a photosensitive thermosetting composition that uses a formulation containing a mixture of epoxy resin and acrylate resin to achieve dual curing properties. However, these systems are not satisfactory because the interfacial bonding between the photocurable acrylate resin and the thermosetting epoxy resin is poor, and the macrostructure after curing is not uniform enough.

[0006] Urea (meth)acrylate polymers, especially polydiene urethane (meth)acrylate (oligomers / polymers containing polydiene segments, urethane links (linkers) and (meth)acrylate functional groups), have low dielectric constants, excellent adhesion properties, and moisture and oxygen barrier properties, and are widely used in laminated adhesives and pressure-sensitive adhesives.

[0007] Traditionally, carbamates are synthesized using three main methods: (1) reaction of chlorocarbamates with ammonia or amines; (2) reaction of carbamoyl chloride with alcohols or phenols; and (3) reaction of isocyanates with alcohols or phenols. However, the raw materials used in these methods, such as chlorocarbamates and carbamoyl chlorides, are synthesized from highly toxic phosgene, which easily causes environmental pollution during production and seriously threatens human safety.

[0008] This application is submitted in response to the above-mentioned issues. Summary of the Invention

[0009] In view of the shortcomings of the existing technology, the first objective of the present invention is to provide an LCD encapsulating adhesive.

[0010] A second objective of this invention is to provide a method for preparing the above-mentioned encapsulating adhesive.

[0011] To achieve the above objectives, the present invention is implemented through the following technical solution: an LCD encapsulating adhesive, comprising, by weight, 22-60% modified resin, 7-15% epoxy resin, 5-9% curing agent, 15-25% filler, 0.5-1.0% photoinitiator, 0.5-1.0% thermal initiator, 7-15% crosslinking agent, 0.3-0.9% polymerization inhibitor, 4-10% toughening agent, and 0.7-1.1% additives; wherein the structural formula of the modified resin is shown in formula (1):

[0012]

[0013] Preferably, the synthetic route of the modified resin is shown in formula (2):

[0014]

[0015] In formula (2), alcohols, amines, liquid epoxy monools, catalysts and solvents are added to a high-pressure reactor. First, CO2 is used to replace the air in the reactor, and then CO2 is introduced. The initial pressure is 0.1-5 MPa. The temperature is raised to 80-120℃ under stirring conditions, and the reaction time is 1-10 h to obtain the modified resin.

[0016] Preferably, in the formula (2), R1 contains a double bond, R2 is a C2-C15 alkyl or aryl group, and R3 is an alkoxy group.

[0017] Preferably, R1 is an acrylate group, a methacrylate group, a diacrylate group, or a triacrylate group, R2 is a C4-C10 cyclic alkane group, a C2-C10 chain alkane group, or a C6-C10 aryl group, and the structural formula of R3 is shown in formula (3):

[0018]

[0019] Where a represents the epoxy group, b represents the hydroxyl group, and R4 represents a C6-C10 aryl, alkyl, or alkoxy group.

[0020] Preferably, the synthetic route of the modified resin is shown in formula (4):

[0021]

[0022] In formula (4), pentaerythritol trihydroxy acrylate, isophorone diamine, liquid epoxy monool, catalyst and solvent are added to a high-pressure reactor. First, the air in the reactor is replaced with CO2, and then CO2 is introduced. The initial pressure is 0.1-3 MPa. The temperature is raised to 80-120℃ under stirring conditions, and the reaction time is 3-8 h to obtain the modified resin.

[0023] Preferably, the catalyst is a combination of an organic base and an organic acid, wherein the organic base is one or more of tetramethylguanidine, n-butylamine, 1,1,3,3-tetramethyl-2-cyclohexylguanidine, 1,1,3,3-tetramethyl-2-phenylguanidine, dicycloamidinium, imidazole, N-methylimidazolium, pyridine, triethylamine, 1,8-diazabicycloundec-7-ene, or 1,5,7-triazabicyclo[4.4.0]dec-5-ene, and the organic acid is one or more of formic acid, acetic acid, or oxalic acid; and the solvent is one or more of acetonitrile, polyethylene glycol, chloro-1-butyl-3-methylimidazolium, bromide-1-methyl-3-butylimidazolium, N-methylpyrrolidone, or dimethylformamide.

[0024] Preferably, the molar ratio of the alcohol compound, amine compound, and liquid epoxy monool is 1:(1.8-2):(1.6-1.8), the catalyst accounts for 0.1-2% of the total mass fraction of the materials, and the volume ratio of the solvent to the liquid epoxy monool is (1-5):1.

[0025] Preferably, the catalyst is a combination of an organic base and an organic acid, wherein the organic base is one or more of tetramethylguanidine, n-butylamine, 1,1,3,3-tetramethyl-2-cyclohexylguanidine, 1,1,3,3-tetramethyl-2-phenylguanidine, dicycloamidinium, imidazole, N-methylimidazolium, pyridine, triethylamine, 1,8-diazabicycloundec-7-ene, or 1,5,7-triazabicyclo[4.4.0]dec-5-ene, and the organic acid is one or more of formic acid, acetic acid, or oxalic acid; and the solvent is one or more of acetonitrile, polyethylene glycol, chloro-1-butyl-3-methylimidazolium, bromide-1-methyl-3-butylimidazolium, N-methylpyrrolidone, or dimethylformamide.

[0026] Preferably, the epoxy resin is one or more of the following: bisphenol A type epoxy resin, hydrogenated bisphenol type epoxy resin, propylene oxide addition bisphenol A type epoxy resin, resorcinol type epoxy resin, biphenyl type epoxy resin, diphenyl ether type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene type epoxy resin, phenolic aldehyde type epoxy resin, glycidylamine type epoxy resin, alkyl polyol type epoxy resin, and rubber modified epoxy resin.

[0027] Preferably, the curing agent is one or more of 1,3-bis(hydrazinoylcarbonylethyl)-5-isopropylhydantoin, 7,11-octadecadiene-1,18-dicarboxylhydrazine, adipic acid dihydrazine, dodecanedicarboxylic acid dihydrazine, and isophthalic acid dihydrazine; the filler is silica particles with a particle size of 500-700 nm; the photoinitiator is one or more of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 4-methylbenzophenone, 1-[4-(phenylthio)-2-(O-benzoyl oxime)], and 2-isopropylthioxanthone; the thermal initiator is azobisisobutyronitrile, azobisisoheptanenitrile, methyl ethyl ketone peroxide, and a condensation polymer of 4,4'-azobis(4-cyanopentanoic acid) and polyalkylene glycol. One or more of the following: the crosslinking agent is one or more of trimethylolpropane triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and N,N'-(4,4'-diphenylmethane)bismaleimide; the polymerization inhibitor is one or more of p-hydroxyanisole, tert-butylcatechol, and phenothiazine; the toughening agent is one or more of nitrile rubber, nano-core-shell rubber epoxy resin toughening agent, and oxetane; the additives include, but are not limited to, mixtures of higher alkanes, fatty acid polyoxyethylene esters, polyoxyethylene polyoxypropylene block copolymers, polyethers, polymethylalkyl groups, polyether polyester modified organosiloxanes, alkyl modified organosiloxanes, end-group modified organosilicones, and epoxy silanes.

[0028] The present invention provides a method for preparing an LCD encapsulating adhesive, comprising the following steps:

[0029] S1: Weigh the modified resin, epoxy resin, curing agent, filler, photoinitiator, thermal initiator, crosslinking agent, polymerization inhibitor, toughening agent and additives according to the weight parts. Mix the modified resin, epoxy resin and photoinitiator in a reactor at a stirring speed of 400-800 rpm for 0.5 h to make them uniformly mixed to obtain the adhesive solution.

[0030] S2: Add thermal initiator and curing agent to the adhesive obtained in step S1, stir for 0.5 h, add crosslinking agent, stir for 0.5 h, add filler, polymerization inhibitor, toughening agent and additives, stir for 0.5 h, and then grind for 1 h with a three-roll mill to obtain LCD encapsulation adhesive.

[0031] The beneficial effects of this invention are:

[0032] 1. This invention involves reacting alcohols, amines, and liquid epoxy monools in a high-pressure reactor with a catalyst and solvent, and then introducing CO2 under specific pressure and temperature to obtain carbamate compounds. This reaction route is a one-step synthesis of carbamate compounds, with a short process flow and simple operation. It uses greenhouse gas CO2 as a raw material, which is beneficial to the ecological environment and is a green process. The reaction conditions are relatively mild, and the only byproduct is water, resulting in high atom utilization.

[0033] 2. This invention involves reacting the two amino groups on isophorone diamine with the hydroxyl groups on pentaerythritol trihydroxyacrylate and liquid epoxy monool under CO2 conditions, respectively, to obtain a modified resin containing two carbamate groups. This reaction route is a one-step synthesis of carbamate compounds, with a short process flow and simple operation. It uses greenhouse gas CO2 as a raw material, which is beneficial to the ecological environment and is a green process. The reaction conditions are relatively mild, and the only byproduct is water, resulting in high atom utilization.

[0034] 3. This invention first cures and shapes a modified resin containing two urethane esters with a photoinitiator, then thermosets it with a thermal initiator and a curing agent, while simultaneously thermosetting the epoxy resin with the curing agent. Finally, it works synergistically with fillers, crosslinking agents, polymerization inhibitors, toughening agents, and additives to provide LCD encapsulation adhesive with excellent long-term reliability, adhesion performance, and service life, thus providing key material support for the large-scale application of liquid crystal display technology. Detailed Implementation

[0035] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0036] Example 1

[0037] An LCD encapsulating adhesive, by weight, comprises 22% modified resin, 15% bisphenol A type epoxy resin, 9% 1,3-bis(hydrazylcarbonylethyl)-5-isopropylhydantoin, 25% silica particles, 1% phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 1% azobisisobutyronitrile, 15% trimethylolpropane triacrylate, 0.9% p-hydroxyanisole, 10% nitrile rubber, and 1.1% additives; wherein the synthetic route of the modified resin is shown in formula (5):

[0038]

[0039]

[0040] In formula (5), poly(ethylene glycol) methacrylate, 1,3-propylenediamine, liquid epoxy monool, catalyst and solvent are added to a high-pressure reactor. First, the air in the reactor is replaced with CO2, and then CO2 is introduced with an initial pressure of 0.1-3 MPa. The temperature is raised to 80-120°C under stirring conditions, and the reaction time is 3-8 h to obtain the modified resin.

[0041] The catalyst is prepared by mixing tetramethylguanidine and formic acid in a mass ratio of 2:1.

[0042] The solvent is acetonitrile.

[0043] The molar ratio of poly(ethylene glycol) methacrylate, 1,3-propylenediamine, and liquid epoxy monool is 1:1.8:1.6, the catalyst accounts for 0.1% of the total mass fraction of the materials, and the volume ratio of the solvent to the liquid epoxy monool is 1:1.

[0044] The preparation method of the LCD encapsulating adhesive includes the following steps:

[0045] S1: Weigh the modified resin, epoxy resin, curing agent, filler, photoinitiator, thermal initiator, crosslinking agent, polymerization inhibitor, toughening agent and additives according to the weight parts. Mix the modified resin, epoxy resin and photoinitiator in a reactor at a stirring speed of 400-800 rpm for 0.5 h to make them uniformly mixed to obtain the adhesive solution.

[0046] S2: Add thermal initiator and curing agent to the adhesive obtained in step S1, stir for 0.5 h, then add crosslinking agent, stir for 0.5 h, then add filler, polymerization inhibitor, toughening agent and additives, stir for 1 h to obtain LCD encapsulation adhesive.

[0047] Example 2

[0048] An LCD encapsulating adhesive, by weight, comprises 32.4% modified resin, 13% propylene oxide addition bisphenol A type epoxy resin, 8% 7,11-octadecadiene-1,18-dicarboxyhydrazide, 23% silica particles, 4-methylbenzophenone, 0.9% 1-[4-(phenylthio)-2-(O-benzoyl oxime)], 0.9% azobisisoheptanenitrile, 12% pentaerythritol tetraacrylate, 0.8% tert-butylcatechol, 8% oxetane, and 1% additives; wherein the synthetic route of the modified resin is shown in formula (6):

[0049]

[0050] In formula (6), hydroxyethyl acrylate, 1,4-cyclohexanediamine, liquid epoxy monool, catalyst and solvent are added to a high-pressure reactor. First, the air in the reactor is replaced with CO2, and then CO2 is introduced with an initial pressure of 0.1-3 MPa. The temperature is raised to 80-120℃ under stirring conditions, and the reaction time is 3-8 h to obtain the modified resin.

[0051] The catalyst is prepared by mixing 1,1,3,3-tetramethyl-2-cyclohexylguanidine and acetic acid in a mass ratio of 4:1.

[0052] The solvent is chloro-1-butyl-3-methylimidazole.

[0053] The molar ratio of hydroxyethyl acrylate, 1,4-cyclohexanediamine, and liquid epoxy monool is 1:1.8:1.6, the catalyst accounts for 0.3% of the total mass fraction of the materials, and the volume ratio of solvent to liquid epoxy monool is 2:1.

[0054] The preparation method of the LCD encapsulating adhesive is the same as in Example 1.

[0055] Example 3

[0056] An LCD encapsulating adhesive, by weight, comprises 41.2% modified resin, 11% diphenyl ether epoxy resin, 7% adipate dihydrazide, 20% silica particles, 0.8% 2-isopropylthioxanthone, 0.8% methyl ethyl ketone peroxide, 11% dipentaerythritol pentaacrylate, 0.3% phenothiazine, 7% oxetane, and 0.9% additives; wherein the synthetic route of the modified resin is shown in formula (7):

[0057]

[0058] In formula (7), 3-acryloyloxy-2-methacrylate hydroxypropyl ester, 1,4-cyclohexanediamine, liquid epoxy monool, catalyst and solvent are added to a high-pressure reactor. First, the air in the reactor is replaced with CO2, and then CO2 is introduced with an initial pressure of 0.1-3 MPa. The temperature is raised to 80-120℃ under stirring conditions, and the reaction time is 3-8 h to obtain the modified resin.

[0059] The catalyst is prepared by mixing N-methylimidazole and oxalic acid in a mass ratio of 6:1.

[0060] The solvent is 1-methyl-3-butylimidazole bromide.

[0061] The molar ratio of 3-acryloyloxy-2-methacrylate hydroxypropyl ester, 1,4-cyclohexanediamine, and liquid epoxy monool is 1:2:1.8, the catalyst accounts for 0.5% of the total mass fraction of the materials, and the volume ratio of the solvent to the liquid epoxy monool is 3:1.

[0062] The preparation method of the LCD encapsulating adhesive is the same as in Example 1.

[0063] Example 4

[0064] An LCD encapsulating adhesive, by weight, comprises 50.9% modified resin, 9% glycidylamine epoxy resin, 6% dodecanedicarboxylic acid dihydrazide, 18% silica particles, 0.6% 4-methylbenzophenone, 0.6% 4,4'-azobis(4-cyanopentanoic acid), 9% dipentaerythritol hexaacrylate, 0.5% p-hydroxyanisole, 5% nano-core-shell rubber epoxy resin toughening agent, and 0.8% additives; wherein the synthetic route of the modified resin is shown in formula (8):

[0065]

[0066] In formula (8), trimethylolpropane diallyl ether, m-phenylenediamine, liquid epoxy monool, catalyst and solvent are added to a high-pressure reactor. First, the air in the reactor is replaced with CO2, and then CO2 is introduced. The initial pressure is 0.1-3 MPa. The temperature is raised to 80-120℃ under stirring conditions, and the reaction time is 3-8 h to obtain the modified resin.

[0067] The catalyst is prepared by mixing tetramethylguanidine 1,5,7-triazabicyclo[4.4.0]dec-5-ene and acetic acid in a mass ratio of 3:1.

[0068] The solvent is N-methylpyrrolidone.

[0069] The molar ratio of trimethylolpropane diallyl ether, m-phenylenediamine, and liquid epoxy monool is 1:2:1.8, the catalyst accounts for 1% of the total mass fraction of the materials, and the volume ratio of the solvent to the liquid epoxy monool is 3:1.

[0070] The preparation method of the LCD encapsulating adhesive is the same as in Example 1.

[0071] Example 5

[0072] An LCD encapsulating adhesive, by weight, comprises 60% modified resin, 7% alkyl polyol epoxy resin, 5% phthalic acid dihydrazide, 15% silica particles, 0.5% phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 0.5% polyalkylene glycol condensate, 7% N,N'-(4,4'-diphenylmethane)bismaleimide, 0.3% tert-butylcatechol, 4% nano-core-shell rubber epoxy resin toughening agent, and 0.7% additives; wherein the synthetic route of the modified resin is shown in formula (4):

[0073]

[0074] In formula (4), pentaerythritol trihydroxy acrylate, isophorone diamine, liquid epoxy monool, catalyst and solvent are added to a high-pressure reactor. First, the air in the reactor is replaced with CO2, and then CO2 is introduced. The initial pressure is 0.1-3 MPa. The temperature is raised to 80-120℃ under stirring conditions, and the reaction time is 3-8 h to obtain the modified resin.

[0075] The catalyst is prepared by mixing 1,1,3,3-tetramethyl-2-cyclohexylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene and oxalic acid in a mass ratio of 2:2:1.

[0076] The solvent is a mixture of N-methylpyrrolidone and dimethylformamide in a volume ratio of 1:1.

[0077] The molar ratio of pentaerythritol trihydroxyacrylate, isophorone diamine, and liquid epoxy monool is 1:2:1.8, the catalyst accounts for 2% of the total mass fraction of the materials, and the volume ratio of the solvent to the liquid epoxy monool is 5:1.

[0078] The preparation method of the LCD encapsulating adhesive is the same as in Example 1.

[0079] Comparative Example 1

[0080] The difference between Comparative Example 1 and Example 1 is that the modified resin was replaced with polyester acrylic resin.

[0081] Comparative Example 2

[0082] The difference between Comparative Example 2 and Example 1 is that the modified resin was replaced with polyether-modified epoxy resin.

[0083] Comparative Example 3

[0084] The difference between Comparative Example 3 and Example 1 is that the modified resin was replaced with 8% aliphatic polyurethane acrylate and 14% hexahydrophthalic acid diglycidyl ester.

[0085] Experimental Example 1

[0086] Experimental groups: Examples 1-5, Comparative Examples 1-3;

[0087] Test method:

[0088] 1. Bond strength

[0089] Apply the sealing adhesive to the center of the upper surface of glass A. Place glass B perpendicular to glass A, with its center aligned with the sealing adhesive. After aligning, spread the sealing adhesive further and apply 100mW / cm² sealant. 2The glass was irradiated with ultraviolet light for 30 seconds and then heated at 120°C for 60 minutes to obtain an adhesive test piece. The adhesive strength of the obtained adhesive test piece was determined using a universal testing machine. Both glass A and glass B are ITO glass with PI coating on the surface, and their dimensions are 25mm×40mm×0.7mm.

[0090] 2. Water vapor transmission rate

[0091] Refer to GB / T 1037-2021 for the determination of water vapor transmission performance of plastic films and sheets.

[0092] 3. Applicable period

[0093] The sealing adhesive was placed in an opaque, sealed container and stored in a constant temperature and humidity chamber at 25°C (50% relative humidity). Samples were taken at the beginning (day 0), day 3, day 5, and day 7 for viscosity testing. The apparent viscosity was measured using a cone-plate viscometer. The seventh day was considered the end of the pot life based on viscosity, defined as the time when the viscosity increased to 120% of the initial value.

[0094] Experimental results: See Table 1 for details.

[0095] Table 1 Test results for each group of projects

[0096]

[0097] Referring to Table 1, the present invention possesses the following properties:

[0098] 1. Strong bonding strength

[0099] The adhesive bonding strength of the encapsulants prepared in Examples 1-5 reached 21.5-28.2 kgf / cm, which is much higher than that of Comparative Examples 1-3, and meets the requirements of LCD encapsulants for bonding performance.

[0100] 2. Excellent long-term reliability

[0101] The water vapor permeability of the encapsulating adhesives prepared in Examples 1-5 was 26.3-29.5 g / (m²). 2 The humidity (24h) is much lower than that of comparative examples 1-3, indicating that the present invention can effectively prevent moisture intrusion and has excellent long-term reliability.

[0102] 3. Excellent service life

[0103] The viscosity change rate of the encapsulating adhesives prepared by Examples 1-5 was 6.35-30.32%, which was much lower than that of Comparative Examples 1-3. Furthermore, the viscosity change rate of Examples 4 (8.24%) and 5 (6.35%) was less than 10%, with a small viscosity change on the 7th day, indicating a better applicable period.

[0104] 4. Process compatibility and mass production capability

[0105] The mixing, three-roll milling, degassing, and curing processes employed are all conventional, with a simple flow that facilitates stable, large-scale production. Furthermore, the synergistic effect among the modified resin, filler, crosslinking agent, polymerization inhibitor, toughening agent, and other additives in the formulation system significantly improves the uniformity of the encapsulating adhesive material and effectively reduces curing stress, further ensuring product reliability and yield.

[0106] In summary, this invention first cures and shapes a modified resin containing two urethane esters with a photoinitiator, then thermosets it with a thermal initiator and a curing agent, and finally allows it to work synergistically with fillers, crosslinking agents, polymerization inhibitors, toughening agents, and additives. This results in an LCD encapsulant with excellent long-term reliability, adhesion performance, and storage stability, providing a key material guarantee for the large-scale application of liquid crystal display technology.

[0107] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0108] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An LCD encapsulating adhesive, characterized in that, The product comprises, by weight, 22-60% modified resin, 7-15% epoxy resin, 5-9% curing agent, 15-25% filler, 0.5-1.0% photoinitiator, 0.5-1.0% thermal initiator, 7-15% crosslinking agent, 0.3-0.9% polymerization inhibitor, 4-10% toughening agent, and 0.7-1.1% additives; wherein the structural formula of the modified resin is shown in formula (1):

2. The LCD encapsulating adhesive as described in claim 1, characterized in that, The synthetic route of the modified resin is shown in formula (2): In formula (2), alcohols, amines, liquid epoxy monools, catalysts and solvents are added to a high-pressure reactor. First, CO2 is used to replace the air in the reactor, and then CO2 is introduced. The initial pressure is 0.1-5 MPa. The temperature is raised to 80-120℃ under stirring conditions, and the reaction time is 1-10 h to obtain the modified resin.

3. The LCD encapsulating adhesive as described in claim 2, characterized in that, In the formula (2), R1 contains a double bond, R2 is a C2-C15 alkyl or aryl group, and R3 is an alkoxy group.

4. The LCD encapsulating adhesive as described in claim 3, characterized in that, R1 is an acrylate group, a methacrylate group, a diacrylate group, or a triacrylate group; R2 is a C4-C10 cyclic alkane group, a C2-C10 chain alkane group, or a C6-C10 aryl group; and the structural formula of R3 is shown in formula (3). Where a represents the epoxy group, b represents the hydroxyl group, and R4 represents a C6-C10 aryl, alkyl, or alkoxy group.

5. The LCD encapsulating adhesive as described in claim 2, characterized in that, The synthetic route of the modified resin is shown in formula (4): In formula (4), pentaerythritol trihydroxy acrylate, isophorone diamine, liquid epoxy monool, catalyst and solvent are added to a high-pressure reactor. First, the air in the reactor is replaced with CO2, and then CO2 is introduced. The initial pressure is 0.1-3 MPa. The temperature is raised to 80-120℃ under stirring conditions, and the reaction time is 3-8 h to obtain the modified resin.

6. The LCD encapsulating adhesive as described in claim 2, characterized in that, The catalyst is a combination of an organic base and an organic acid. The organic base is one or more of tetramethylguanidine, n-butylamine, 1,1,3,3-tetramethyl-2-cyclohexylguanidine, 1,1,3,3-tetramethyl-2-phenylguanidine, dicycloamidinium, imidazole, N-methylimidazolium, pyridine, triethylamine, 1,8-diazabicycloundec-7-ene, or 1,5,7-triazabicyclo[4.4.0]dec-5-ene. The organic acid is one or more of formic acid, acetic acid, or oxalic acid. The solvent is one or more of acetonitrile, polyethylene glycol, chloro-1-butyl-3-methylimidazolium, bromide-1-methyl-3-butylimidazolium, N-methylpyrrolidone, or dimethylformamide.

7. The LCD encapsulating adhesive as described in claim 2, characterized in that, The molar ratio of the alcohol, amine, and liquid epoxy monool is 1:(1.8-2):(1.6-1.8), the catalyst accounts for 0.1-2% of the total mass fraction of the materials, and the volume ratio of the solvent to the liquid epoxy monool is (1-5):

1.

8. The LCD encapsulating adhesive as described in claim 1, characterized in that, The epoxy resin is one or more of the following: bisphenol A type epoxy resin, hydrogenated bisphenol type epoxy resin, propylene oxide addition bisphenol A type epoxy resin, resorcinol type epoxy resin, biphenyl type epoxy resin, diphenyl ether type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene type epoxy resin, phenolic aldehyde type epoxy resin, glycidylamine type epoxy resin, alkyl polyol type epoxy resin, and rubber modified epoxy resin.

9. The LCD encapsulating adhesive as described in claim 1, characterized in that, The curing agent is one or more of 1,3-bis(hydrazinoylcarbonylethyl)-5-isopropylhydantoin, 7,11-octadecadiene-1,18-dicarboxylhydrazine, adipate dihydrazine, dodecanedicarboxylic acid dihydrazine, and isophthalic acid dihydrazine; the filler is silica particles with a particle size of 500-700 nm; the photoinitiator is one or more of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 4-methylbenzophenone, 1-[4-(phenylthio)-2-(O-benzoyl oxime)], and 2-isopropylthioxanthone; the thermal initiator is one or more of azobisisobutyronitrile, azobisisoheptanenitrile, methyl ethyl ketone peroxide, and a condensation polymer of 4,4'-azobis(4-cyanopentanoic acid) and polyalkylene glycol. One or more of the following: the crosslinking agent is one or more of trimethylolpropane triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and N,N'-(4,4'-diphenylmethane)bismaleimide; the polymerization inhibitor is one or more of p-hydroxyanisole, tert-butylcatechol, and phenothiazine; the toughening agent is one or more of nitrile rubber, nano-core-shell rubber epoxy resin toughening agent, and oxetane; the additives include, but are not limited to, mixtures of higher alkanes, fatty acid polyoxyethylene esters, polyoxyethylene polyoxypropylene block copolymers, polyethers, polymethylalkyl groups, polyether polyester modified organosiloxanes, alkyl modified organosiloxanes, end-group modified organosilicones, and epoxy silanes.

10. A method for preparing an LCD encapsulating adhesive as described in any one of claims 1-9, characterized in that, Includes the following steps: S1: Weigh the modified resin, epoxy resin, curing agent, filler, photoinitiator, thermal initiator, crosslinking agent, polymerization inhibitor, toughening agent and additives according to the weight parts. Mix the modified resin, epoxy resin and photoinitiator in a reactor at a stirring speed of 400-800 rpm for 0.5 h to make them uniformly mixed to obtain the adhesive solution. S2: Add thermal initiator and curing agent to the adhesive obtained in step S1, stir for 0.5 h, add crosslinking agent, stir for 0.5 h, add filler, polymerization inhibitor, toughening agent and additives, stir for 0.5 h, and then grind for 1 h using a three-roll mill to obtain LCD encapsulation adhesive.

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