Dual-curing frame sealing glue for liquid crystal display screen and preparation method of dual-curing frame sealing glue

Abstract

The invention discloses a dual-curing frame sealing adhesive for a liquid crystal display screen, which is prepared from the following components in parts by weight: 37 to 62 percent of modified resin, 8 to 18 percent of epoxy resin, 12 to 16 percent of curing agent, 1.4 to 2.2 percent of reactive diluent, 15 to 22 percent of nano inorganic filler, 0.5 to 2 percent of photoinitiator, 0.5 to 1 percent of coupling agent, 0.2 to 0.5 percent of antioxidant and 0.4 to 1.3 percent of additive. Wherein the modified resin is formed by mixing a compound A and a compound B according to a ratio of 1: 3. The preparation method specifically comprises the following steps: stirring the epoxy resin, the modified 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 the curing agent and the active diluent into the glue solution, stirring for 0.5 h, adding the coupling agent, stirring for 0.5 h, adding the nano inorganic filler, the antioxidant and the auxiliary agent, stirring for 0.5 h, and grinding for 1 h by a three-roller grinder to obtain the dual-curing frame sealing glue for the liquid crystal display screen. The prepared dual-curing frame sealing glue for the liquid crystal display screen has excellent bonding strength and high-temperature and high-humidity resistance, and the liquid crystal display screen is not prone to being polluted.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of double-curing frame sealant for liquid crystal display and its preparation method, belong to the material science and electronic packaging in the technical field of liquid crystal display. BACKGROUND

[0002] Liquid crystal display device has become the mainstream display scheme of various consumer electronic products due to its excellent visual performance, low power consumption, thinness and wide applicability. The device mainly includes a backlight module and a liquid crystal display panel, wherein the panel is composed of a color filter (CF) substrate, a thin film transistor (TFT) array substrate, a liquid crystal medium and a sealant. During the manufacturing process, the array substrate (TFT) and the color film substrate (CF) need to be combined, and the liquid crystal is sealed between the two substrates. The sealant serves to bond the array substrate and the color film substrate and forms a sealed container between the two substrates, ensuring that the liquid crystal is not affected by any external factors.

[0003] In the panel cell process, the amount of sealant used is very small, but it plays a key role in maintaining the stability of the overall structure and preventing water vapor from entering. Traditional sealants have insufficient water vapor barrier performance and low adhesion strength, which can easily lead to bonding failure or water vapor penetration under environmental changes, resulting in various defects in the panel and seriously affecting the reliability of the liquid crystal display and the overall product yield. To balance high-precision fine-line processing and excellent bonding performance, low liquid crystal contamination, aging resistance and moisture resistance, the industry is committed to developing resin systems with both double bonds and epoxy functional groups. This type of dual-functional resin can form a stable three-dimensional cross-linked structure after pre-curing under ultraviolet light and then heat treatment, so it is a key material basis for achieving high-performance sealants.

[0004] CN114106742A discloses a high-viscosity liquid crystal frame sealant, which comprises the following components by weight: epoxy resin 10-20 parts, acrylic resin 40-60 parts, bismaleimide resin 0.2-2 parts, photoinitiator 0.2-2 parts, organic filler 15-30 parts, coupling agent 0.2-2 parts, silicon dioxide 0.2-3 parts, and thermal curing agent 10-20 parts. The thermal curing agent uses malonic acid dihydrazide curing agent. The viscosity of the sealant has been greatly improved, and the adhesion of the sealant has been improved without affecting other properties of the product, effectively preventing the leakage of liquid crystal. However, the high temperature and high humidity resistance of the sealant needs to be improved. In a high temperature and high humidity environment, water vapor and oxygen cannot be effectively prevented from entering, thereby cannot effectively ensure the performance of the liquid crystal display device is not affected by the environment for a long time, and the liquid crystal may be contaminated.

[0005] To solve the above problems, the present application is proposed. SUMMARY

[0006] In view of the deficiencies of the prior art, the first object of the present application is to provide a double-curing frame sealing adhesive for liquid crystal display screens.

[0007] The second object of the present application is to provide a preparation method of the frame sealing adhesive.

[0008] To achieve the above object, the present application is implemented by the following technical solution: a double-curing frame sealing adhesive for liquid crystal display screens, comprising, by weight, 37-62% of modified resin, 8-18% of epoxy resin, 12-16% of curing agent, 1.4-2.2% of active diluent, 15-22% of nano inorganic filler, 0.5-2% of photoinitiator, 0.5-1% of coupling agent, 0.2-0.5% of antioxidant, and 0.4-1.3% of auxiliary agent; wherein the modified resin is a mixture of compound A and compound B in a ratio of 1:3, the structural formula of the compound A is shown in formula (1):

[0009] the structural formula of the compound B is shown in formula (2):

[0010]

[0011] Preferably, the synthesis route of the compound A is shown in formula (3):

[0012]

[0013] In formula (3), in a high-pressure reaction kettle, alcohol compound, amine compound, liquid epoxy monol, catalyst and solvent are added, the air in the kettle is replaced with CO2 first, then CO2 is introduced, the initial pressure is 0.1-5 MPa, the temperature is raised to 80-120 DEG C under stirring, and the reaction time is 1-10 h to obtain the compound A.

[0014] Preferably, the R1 contains ethyl propyl ether group, diene propyl ether group or triene propyl ether group, and the R2 is ether group.

[0015] Preferably, the catalyst is a combination of organic base and organic acid, the organic base is one or more of tetramethylguanidine, n-butylamine, 1,1,3,3-tetramethyl-2-cyclohexyl guanidine, 1,1,3,3-tetramethyl-2-phenyl guanidine, bicyclic amidine, imidazole, N-methyl imidazole, pyridine, triethylamine, 1,8-diazabicyclo[5.4.0]undec-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; the solvent is one or more of acetonitrile, polyethylene glycol, chloro-1-butyl-3-methyl imidazole, bromo-1-methyl-3-butyl imidazole, N-methyl pyrrolidone or dimethylformamide.

[0016] Preferably, the molar ratio of the alcohol compound, the amine compound and the liquid epoxy monol is 1: (1.8-2): (1.6-1.8), the mass fraction of the catalyst in the total material is 0.1-2%, and the volume ratio of the solvent to the liquid epoxy monol is (1-5): 1.

[0017] Preferably, the epoxy resin is one or more of bisphenol A type epoxy resin, hydrogenated bisphenol type epoxy resin, epoxy propane 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, phenol formaldehyde type epoxy resin, glycidyl amine type epoxy resin, alkyl polyol type epoxy resin, and rubber modified type epoxy resin.

[0018] Preferably, the curing agent is an organic hydrazine curing agent, including but not limited to one or more of sebacic acid dihydrazide, isophthalic acid dihydrazide, adipic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, isophthalic acid dihydrazide, dodecanedioic acid dihydrazide, 1,3-bis(hydrazinocarbonethyl)-5-isopropyl hydantoin, malic acid dihydrazide and tartaric acid dihydrazide; the active diluent is one or more of propylene oxide butyl ether, propylene oxide phenyl ether, benzyl glycidyl ether, tertiary glycidyl ether, 1,4-butanediol glycidyl ether; the nano inorganic filler is one or more of nano titanium dioxide, nano silicon dioxide, nano zinc oxide and nano quartz powder, and the average particle size of the nano inorganic filler is 150-250 nm.

[0019] Preferably, the photoinitiator is one or more of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyl-diphenyl phosphine oxide and 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone.

[0020] Preferably, the coupling agent is one or more of KH-550, KH560 or KH570; the antioxidant is one or more of 2,6-di-tert-butyl-p-cresol, tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid octadecyl ester; the auxiliary agent includes but is not limited to one or more of polyester polyol, glycerol, polyether, polymethylalkyl, polyether polyester modified organosiloxane, alkyl modified organosiloxane, end group modified organosilicon and epoxy silane.

[0021] Preferably, it is characterized by comprising the following steps:

[0022] S1: The modified resin, epoxy resin, curing agent, active diluent, nano inorganic filler, photoinitiator, coupling agent, antioxidant and auxiliary agent are weighed according to the weight fraction; the modified resin, epoxy resin and photoinitiator are uniformly mixed in a reaction kettle at a stirring speed of 400-800 rpm for 0.5 h to obtain a glue solution;

[0023] S2: The curing agent and active diluent are added to the glue solution obtained in step S1, and after stirring for 0.5 h, the coupling agent is added, and after stirring for 0.5 h, the nano inorganic filler, antioxidant and auxiliary agent are added, and after stirring for 0.5 h, the liquid crystal display screen is obtained by grinding for 1 h through a three-roll grinding machine.

[0024] The above technical scheme, the modified resin contains epoxy groups and acrylate groups, the resin can be UV cured and heat cured respectively, UV curing is generated by the above photoinitiator through ultraviolet light irradiation to produce free radicals, the free radicals initiate the crosslinking reaction of the acrylate double bond group, the heat curing is the crosslinking reaction of the amine group contained in the curing agent and the epoxy group contained in the resin through the ring opening of the heat oven, forming two stable crosslinking network structures, so that the modified resin system has double curing function; in addition, the acrylate end group of the modified resin can provide a free radical polymerization active site, the epoxy group provides a ring-opening polymerization active site, and the ether bond can increase the flexibility and chemical stability of the molecule; the urethane is a strong polar group, which can produce stronger van der Waals force and hydrogen bond action with the surface of the base material, and excellent adhesion and toughness, weather resistance, chemical resistance can be effectively improved. The overall modified resin system can significantly improve the curing speed and hardness, while retaining flexible chain and avoiding brittleness, realizing the synergistic effect of flexible chain and high crosslinking network, and showing excellent performance in bonding performance and water resistance and moisture resistance.

[0025] The beneficial effects of the present application are:

[0026] 1、The present application obtains the urethane compound A by adding the catalyst and solvent into the high-pressure reaction kettle, and introducing CO2 under certain pressure and temperature, which is a one-step synthesis of urethane compound, has short process flow and simple operation; uses greenhouse gas CO2 as raw material, which is beneficial to the ecological environment and is a green process; the reaction condition is relatively mild; the byproduct is only water, and the atomic utilization rate is high.

[0027] 2、The present application obtains the modified resin by compounding the compound A containing two urethane and the compound B containing two urethane, and adopts light curing and heating curing, which shortens the curing time and the pollution of the frame sealing glue to the liquid crystal.

[0028] 3、The modified resin is prepared by compounding compound A and compound B, and then is firstly solidified and shaped with a photoinitiator, and then is heat solidified with a curing agent, while the epoxy resin is heat solidified with the curing agent, and finally the active diluent, coupling agent, nano inorganic filler, antioxidant and additive play a synergistic effect, so that the double-curing frame sealing glue for liquid crystal display screens not only has excellent bonding strength, but also has small moisture permeability and small bonding strength loss in a high temperature and high humidity environment, still maintains excellent bonding performance, can effectively block water vapor and oxygen from invading the liquid crystal display to cause the liquid crystal display to be polluted, and can be widely applied to liquid crystal displays. DETAILED DESCRIPTION

[0029] In order to make the technical means, creative features, purposes and effects of the present application easy to understand, the present application is further described below in combination with specific embodiments.

[0030] Embodiment 1

[0031] A double-curing frame sealing glue for liquid crystal display screens comprises, by weight, 37% of modified resin, 18% of hydrogenated bisphenol type epoxy resin, 16% of sebacic acid dihydrazide, 2.2% of epoxy propane butyl ether, 22% of nano titanium dioxide, 2% of 2-hydroxy-2-methyl-1-phenylpropanone, 1% of KH-550, 0.5% of 2,6-di-tert-butyl-p-cresol, 0.8% of polyester polyol and 0.5% of polyether, wherein the modified resin is prepared by mixing compound A and compound B at a ratio of 1:3, the structural formula of the compound A is shown as formula (4):

[0032] The structural formula of the compound B is shown as formula (2):

[0033]

[0034] Preferably, the synthesis route of the compound A is shown as formula (5):

[0035]

[0036] In formula (5), allyl hydroxyethyl ether, bis(3-aminopropyl) ether, liquid epoxy monol, a catalyst and a solvent are added into a high-pressure reaction kettle, the air in the kettle is replaced with CO2, then CO2 is introduced, the initial pressure is 0.1-5 MPa, the temperature is increased to 80-120 DEG C under stirring, and the reaction time is 1-10 h, so as to obtain the compound A.

[0037] Preferably, the catalyst is prepared by configuring tetramethyl guanidine and formic acid at a mass ratio of 2:1, and the solvent is acetonitrile.

[0038] Preferably, the mass ratio of the allyl hydroxyethyl ether, bis(3-aminopropyl) ether, liquid epoxy monol is 1:1.8:1.6, the mass fraction of the catalyst in the total material is 0.1%, and the volume ratio of the solvent to the liquid epoxy monol is 1:1.

[0039] The average particle size of the nano inorganic filler is 150-250 nm.

[0040] Preferably, it is characterized by comprising the following steps:

[0041] S1: The modified resin, epoxy resin, curing agent, active diluent, nano inorganic filler, photoinitiator, coupling agent, antioxidant and auxiliary agent are weighed according to the weight fraction; the modified resin, epoxy resin and photoinitiator are mixed uniformly in a reaction kettle at a stirring speed of 400-800 rpm for 0.5 h to obtain a glue solution;

[0042] S2: The curing agent and active diluent are added to the glue solution obtained in step S1, and after stirring for 0.5 h, the coupling agent is added, and after stirring for 0.5 h, the nano inorganic filler, antioxidant and auxiliary agent are added, and after stirring for 0.5 h, the mixture is ground by a three-roll grinding machine for 1 h to obtain a double-curing frame sealant for liquid crystal display screens.

[0043] Example 2

[0044] A double-curing frame sealant for liquid crystal display screens, comprising, by weight fraction, modified resin 44%, biphenyl type epoxy resin 16%, isophthalic dihydrazide 14%, epoxy propane phenyl ether 2%, nano silicon dioxide 20%, 1-hydroxy cyclohexyl phenyl ketone 1.8%, KH560 0.8%, tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester 0.4%, glycerol 0.8%, and polymethyl alkyl 0.2%; wherein the modified resin is a mixture of compound A and compound B in a ratio of 1:3, the structural formula of the compound A is shown as formula (6):

[0045] The structural formula of the compound B is shown as formula (2):

[0046]

[0047] Preferably, the synthesis route of the compound A is shown as formula (7):

[0048]

[0049] In formula (7), in a high-pressure reactor, trimethylolpropane diallyl ether, 3,4'-diaminodiphenyl ether, liquid epoxy monol, catalyst and solvent are added, the reactor is replaced with CO2, then CO2 is introduced, the initial pressure is 0.1-5 MPa, under stirring, the temperature is raised to 80-120℃, and the reaction time is 1-10 h, to obtain compound A.

[0050] Preferably, the catalyst is 1,1,3,3-tetramethyl-2-cyclohexyl guanidine and acetic acid, and the mass ratio is 4:1; and the solvent is polyethylene glycol.

[0051] Preferably, the mass ratio of trimethylolpropane diallyl ether, 3,4'-diaminodiphenyl ether and liquid epoxy monol is 1:1.8:1.6, the mass fraction of the catalyst in the total material is 0.3%, and the volume ratio of the solvent to liquid epoxy monol is 2:1.

[0052] The average particle size of the nano inorganic filler is 150-250 nm.

[0053] The preparation method of the double-curing frame sealant for liquid crystal display screens is the same as that in Example 1.

[0054] Example 3

[0055] A double-curing frame sealant for liquid crystal display screens, characterized in that, by weight, it comprises modified resin 48.2%, dicyclopentadiene type epoxy resin 14%, isophthalic acid dihydrazide 15%, benzyl glycidyl ether 1.8%, nano zinc oxide 18%, 2,4,6-trimethylbenzoyl-diphenyl phosphine oxide 1.3%, KH570 0.7%, β-(3,5-di-tert-butyl-4-hydroxyphenyl) octadecyl propionate 0.3%, glycerol 0.5%, and alkyl-modified organosiloxane 0.2%; wherein the modified resin is a mixture of compound A and compound B in a ratio of 1:3, the structural formula of the compound A is shown in formula (8):

[0056] The structural formula of the compound B is shown in formula (2):

[0057]

[0058] Preferably, the synthesis route of the compound A is shown in formula (9):

[0059]

[0060] In formula (9), in a high-pressure reactor, pentaerythritol triallyl ether, 2-aminopropyl-terminated polypropylene glycol, liquid epoxy monol, catalyst and solvent are added, the reactor is replaced with CO2, then CO2 is introduced, the initial pressure is 0.1-5 MPa, under stirring, the temperature is raised to 80-120℃, and the reaction time is 1-10 h, to obtain compound A.

[0061] Preferably, the catalyst is N-methyl imidazole and oxalic acid configured according to a mass ratio of 6:1; and the solvent is bromide-1-methyl-3-butyl imidazole.

[0062] Preferably, the mass ratio of pentaerythritol triallyl ether, 2-aminopropyl-terminated polypropylene glycol and liquid epoxy monol is 1:1.8:1.6, the mass fraction of the catalyst in the total material is 0.5%, and the volume ratio of the solvent to the liquid epoxy monol is 3:1.

[0063] The average particle size of the nano inorganic filler is 150-250 nm.

[0064] The preparation method of the dual-curing frame sealant for liquid crystal display screens is the same as that in Example 1.

[0065] Example 4

[0066] A dual-curing frame sealant for liquid crystal display screens, characterized by comprising, in parts by weight, 55% of modified resin, 12% of phenol novolac type epoxy resin, 13% of 1,3-bis(hydrazine carbonyl ethyl)-5-isopropyl hydantoin, 1.6% of tertiary carbonic acid glycidyl ether, 16% of nano titanium dioxide, 1% of 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone, 0.6% of KH560, 0.3% of 2,6-di-tert-butyl-p-cresol, 0.4% of polyester polyol and 0.1% of end group modified organosilicon; wherein the modified resin is a mixture of compound A and compound B according to a ratio of 1:3, the structural formula of the compound A is shown in formula (10):

[0067] The structural formula of the compound B is shown in formula (2):

[0068]

[0069] Preferably, the synthesis route of the compound A is shown in formula (11):

[0070]

[0071] In formula (11), in a high-pressure reactor, polyethylene glycol monoallyl ether, 1,8-diamino-3,6-dioxaoctane, liquid epoxy monol, catalyst and solvent are added, the reactor is replaced with CO2, then CO2 is introduced, the initial pressure is 0.1-5 MPa, the temperature is raised to 80-120°C under stirring, and the reaction time is 1-10 h to obtain compound A.

[0072] Preferably, the catalyst is tetramethyl guanidine 1,5,7-triazabicyclo[4.4.0]dec-5-ene and acetic acid in a mass ratio of 3:1; and the solvent is N-methyl pyrrolidone.

[0073] Preferably, the mass ratio of polyethylene glycol monoallyl ether, 1,8-diamino-3,6-dioxaoctane and liquid epoxy monol is 1:2:1.8, the mass fraction of the catalyst in the total material is 1%, and the volume ratio of the solvent to liquid epoxy monol is 4:1.

[0074] The average particle size of the nano inorganic filler is 150-250 nm.

[0075] The preparation method of the dual-curing frame sealant for liquid crystal display screens is the same as that in Embodiment 1.

[0076] Embodiment 5

[0077] A dual-curing frame sealant for liquid crystal display screens, characterized in that it comprises, by weight parts, 62% of modified resin, 8% of rubber-modified epoxy resin, 12% of tartaric acid dihydrazide, 1.4% of 1,4-butanediol glycidyl ether, 15% of nano quartz powder, 0.5% of 2,4,6-trimethylbenzoyl-diphenyl phosphine oxide, 0.5% of KH570, 0.2% of 2,6-di-tert-butyl-p-cresol, 0.3% of polyester polyol and 0.1% of epoxy silane; wherein the modified resin is a mixture of compound A and compound B in a ratio of 1:3, the structural formula of the compound A is shown in formula (12):

[0078] The structural formula of the compound B is shown in formula (2):

[0079]

[0080] Preferably, the synthesis route of the compound A is shown in formula (13):

[0081]

[0082] In formula (13), pentaerythritol triallyl ether, bis(3-aminopropyl) ether, liquid epoxy monool, catalyst and solvent are added to a high-pressure reactor. The air in the reactor is first replaced with CO2, and then CO2 is introduced with an initial pressure of 0.1-5 MPa. The temperature is raised to 80-120°C under stirring, and the reaction time is 1-10 h to obtain compound A.

[0083] Preferably, the catalyst is prepared by mixing 1,1,3,3-tetramethyl-2-cyclohexylguanidine, 1,5,7-triazabicyclo[4.4.0]decene and oxalic acid in a mass ratio of 2:2:1; and the solvent is prepared by mixing N-methylpyrrolidone and dimethylformamide in a volume ratio of 1:1.

[0084] Preferably, the molar ratio of pentaerythritol triallyl ether, aminopropyl ether, 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.

[0085] The preparation method of the dual-curing sealant for the liquid crystal display screen is the same as in Example 1.

[0086] Comparative Example 1

[0087] The difference between Comparative Example 1 and Example 1 is that the modified resin was replaced with bisphenol A epoxy resin.

[0088] Comparative Example 2

[0089] The difference between Comparative Example 2 and Example 1 is that the modified resin was replaced with aromatic polyurethane hexaacrylate.

[0090] Comparative Example 3

[0091] The difference between Comparative Example 3 and Example 1 is that the modified resin was replaced with 15% aliphatic polyurethane hexaacrylate and 40% hexahydrophthalic acid diglycidyl ester.

[0092] Test method:

[0093] 1. Bond strength

[0094] Apply the sealant to the center of the upper surface of glass A. Place glass B perpendicular to glass A, with its center aligned with the sealant. After aligning, spread the sealant further and apply 100mW / cm² sealant. 2 The 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.

[0095] 2. High temperature and high humidity resistance

[0096] Adhesion strength loss rate: The adhesion test pieces were prepared by the same method as above, and were placed in an environment with a temperature of 85°C and a relative humidity of 85% for 240h, and then the adhesion strength was tested. The adhesion strength loss rate was calculated by comparing the original adhesion strength.

[0097] Whether the liquid crystal is contaminated: The sealant was prepared into a liquid crystal cell, and the liquid crystal cell was placed in an environment with a temperature of 85°C and a relative humidity of 85% for 240h. Then, whether the liquid crystal was contaminated was observed under a polarizer. No blue-purple light halo phenomenon indicated that the liquid crystal was not contaminated, and a blue-purple light halo phenomenon indicated that the liquid crystal was contaminated.

[0098] 3. Moisture permeability

[0099] The sealant was first irradiated with 100mW / cm 2 of ultraviolet light for 30s, and then heated at 120°C for 60min, and then cooled to room temperature, cut, and a film piece with a diameter of 55mm and a thickness of 300μm was prepared. The film piece was placed in a moisture permeability cup, and calcium chloride was added. The moisture permeability was calculated by dividing the water absorption of calcium chloride by the area of the film.

[0100] Test results: See Table 1.

[0101] Table 1: Test results of each group

[0102]

[0103] According to Table 1, the present application has the following properties:

[0104] 1. Strong adhesion strength

[0105] The adhesion strength of the sealant prepared by Examples 1-5 was 24.8-29.4kgf / cm, which was much higher than that of Comparative Examples 1-3, and met the requirements of the adhesion strength of the sealant in a liquid crystal display screen.

[0106] 2. Low adhesion strength loss rate

[0107] The adhesion strength loss rate of the sealant prepared by Examples 1-5 was 0.93-1.24%, which was much lower than that of Comparative Examples 1-3, indicating that the adhesion strength loss of the sealant prepared by the present application was small in a high temperature and high humidity environment.

[0108] 3. Liquid crystal is not contaminated

[0109] The sealing adhesive prepared in Examples 1-5 was then used to prepare liquid crystal cells. Under high temperature and high humidity conditions, the liquid crystal cells were observed to be uncontaminated using a polarizer, while the liquid crystal cells of Comparative Examples 1-3 were contaminated. This indicates that the sealing adhesive prepared in this invention can effectively block the entry of water vapor and oxygen under high temperature and high humidity conditions, and the liquid crystal is not contaminated.

[0110] 4. Low moisture permeability

[0111] The moisture permeability of the sealing adhesives prepared in Examples 1-5 was 24.3-29.0 g / m³. 2 The moisture permeability is much lower than that of comparative examples 1-3, indicating that the sealing adhesive prepared in this invention has a low moisture permeability under high temperature and high humidity conditions.

[0112] 5. Process compatibility and mass production capability

[0113] 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, reactive diluent, antioxidant, toughening agent, and other additives in the formulation significantly improves the uniformity of the sealing adhesive material and effectively reduces curing stress, further ensuring product reliability and yield.

[0114] In summary, the dual-curing sealant for liquid crystal displays prepared by this invention not only has excellent bonding strength, but also maintains excellent bonding performance with low moisture permeability and minimal loss of bonding strength under high temperature and high humidity conditions. It can effectively prevent water vapor and oxygen from entering the liquid crystal display and causing contamination, and can be widely used in liquid crystal displays.

[0115] 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.

[0116] 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. A dual-curing sealant for liquid crystal displays, characterized in that, By weight, including modified resin 37-62%, epoxy resin 8-18%, curing agent 12-16%, active diluent 1.4-2.2%, nano inorganic filler 15-22%, photoinitiator 0.5-2%, coupling agent 0.5-1%, antioxidant 0.2-0.5%, auxiliary 0.4-1.3%; wherein, the modified resin is compound A and compound B mixed according to 1:3, the structural formula of the compound A is shown as formula (1): The structural formula of the compound B is shown as formula (2):

2. The dual-curing sealant for liquid crystal display panels according to claim 1, wherein the sealant composition comprises 0.1 to 10 parts by weight of the compound represented by the general formula (1) based on 100 parts by weight of the epoxy resin. The synthesis route of the compound A is shown as formula (3): In formula (3), in the high-pressure reaction kettle, add alcohol compound, amine compound, liquid epoxy monol, catalyst and solvent, first replace the air in the kettle with CO2, then introduce CO2, the initial pressure is 0.1-5MPa, under stirring, the temperature is raised to 80-120℃, the reaction time is 1-10h, to obtain compound A.

3. The dual-curing sealant for liquid crystal display panels according to claim 1, wherein the sealant composition comprises 0.1 to 10 parts by weight of the compound represented by the general formula (1) based on 100 parts by weight of the epoxy resin. The R1 contains ethyl propylene ether group, diene propyl ether group or triene propyl ether group, and R2 is ether group.

4. The dual-curing sealant for liquid crystal display panels according to claim 2, wherein the sealant composition comprises 0.1 to 10 parts by weight of the compound represented by the general formula (1) based on 100 parts by weight of the epoxy resin. The catalyst is a combination of organic base and 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, bicycloamidine, imidazole, N-methyl imidazole, pyridine, triethylamine, 1,8-diazabicyclo[5.4.0]undec-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; the solvent is one or more of acetonitrile, polyethylene glycol, chloro-1-butyl-3-methylimidazole, bromo-1-methyl-3-butyl imidazole, N-methyl pyrrolidone or dimethylformamide.

5. The dual-curing sealant for liquid crystal display panels according to claim 2, wherein the sealant composition is a mixture of the first sealant composition and the second sealant composition. The molar ratio of the alcohol compound, amine compound and liquid epoxy monol is 1:(1.8-2):(1.6-1.8), the mass fraction of the catalyst in the total material is 0.1-2%, and the volume ratio of the solvent to the liquid epoxy monol is (1-5):

1.

6. The dual-curing sealant for liquid crystal display panels according to claim 1, wherein The epoxy resin is one or more of 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, phenol formaldehyde type epoxy resin, glycidyl amine type epoxy resin, alkyl polyol type epoxy resin, and rubber modified type epoxy resin.

7. The dual-curing sealant for liquid crystal display panels according to claim 1, wherein the sealant is a sealant for a liquid crystal display panel. The curing agent is an organic hydrazine curing agent, including but not limited to one or more of decanedioic acid dihydrazide, isophthalic acid dihydrazide, hexanedioic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, isophthalic acid dihydrazide, dodecanedioic acid dihydrazide, 1,3-bis(hydrazinocarbonethyl)-5-isopropyl hydantoin, malic acid dihydrazide and tartaric acid dihydrazide; the active diluent is one or more of propylene oxide butyl ether, propylene oxide phenyl ether, benzyl glycidyl ether, tertiary glycidyl ether, 1,4-butanediol glycidyl ether; the nano inorganic filler is one or more of nano titanium dioxide, nano silicon dioxide, nano zinc oxide and nano quartz powder, and the average particle size of the nano inorganic filler is 150-250 nm.

8. The dual-curing sealant for liquid crystal display panels according to claim 1, wherein The photoinitiator is one or more of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyl-diphenyl phosphine oxide and 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy) phenyl]-1-propanone.

9. The dual-curing sealant for liquid crystal display panels according to claim 1, wherein The coupling agent is one or more of KH-550, KH560 or KH570; the antioxidant is one or more of 2,6-di-tert-butyl-p-cresol, tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid octadecyl ester; the auxiliary agent includes but is not limited to one or more of polyester polyol, glycerol, polyether, polymethylalkyl, polyether polyester modified organosiloxane, alkyl modified organosiloxane, end group modified organosilicon and epoxy silane.

10. A method for preparing the dual-curing sealant for liquid crystal display panel according to any one of claims 1 to 9, characterized by, The method comprises the following steps: S1: according to the weight part, the modified resin, the epoxy resin, the curing agent, the active diluent, the nano inorganic filler, the photoinitiator, the coupling agent, the antioxidant and the auxiliary agent are weighed; the modified resin, the epoxy resin and the photoinitiator are mixed uniformly in a reaction kettle at a stirring speed of 400-800 rpm for 0.5 h to obtain a glue solution; S2: the curing agent and the active diluent are added to the glue solution obtained in step S1, and after stirring for 0.5 h, the coupling agent is added, and after stirring for 0.5 h, the nano inorganic filler, the antioxidant and the auxiliary agent are added, and after stirring for 0.5 h, the liquid crystal display screen is obtained by grinding for 1 h through a three-roll grinding machine.

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