Epoxy resin frame sealing glue, glue film and preparation method

Abstract

The invention discloses an epoxy resin frame sealing adhesive, an adhesive film and a preparation method. The epoxy resin frame sealing adhesive is prepared from the following raw materials in parts by weight: 20-30 parts of epoxy resin, 3-12 parts of polyether modified flexible epoxy resin, 5-30 parts of modified nitrile rubber, 13-25 parts of a mercaptan curing agent, 5-25 parts of filler, 1-3 parts of an accelerant, 0.1-0.5 part of a stabilizer, 1-5 parts of a coupling agent, 3-10 parts of fumed silica and 0.1-0.5 part of carbon black. The epoxy resin frame sealing glue can be rapidly cured at low temperature, has excellent storage stability at low temperature, has a proper expansion coefficient, and can ensure the stability and reliability of the flexible screen in the using process after frame sealing.

Description

Technical Field

[0001] The invention belongs to the technical field of epoxy resin frame sealing adhesive, and in particular relates to an epoxy resin frame sealing adhesive, an adhesive film and a preparation method thereof. Background Art

[0002] The successful mass production of flexible screens, namely OLEDs, is not only a significant boon to the manufacturing of a new generation of high-end smartphones, but also has a profound impact on the application of wearable devices due to its low power consumption and bendable characteristics. In the future, flexible screens will be widely used as personal smart terminals continue to penetrate.

[0003] The weakness of OLED is that it is afraid of oxygen and water. Once oxygen or water vapor enters the device, it will cause the device life to decay. Therefore, for flexible OLED devices, its life depends on the barrier of flexible substrate and packaging technology to oxygen and water vapor. In OLED packaging, epoxy resin frame sealant is widely used in OLED display edge sealing due to its good stability, low curing shrinkage, high mechanical strength of cured products, and excellent processing technology. Its rheological properties are suitable for high-speed production. It can be evenly applied to the edges of the protective film and can quickly penetrate to form a consistent filling. However, the current epoxy resin frame sealant has average toughness, and the frame is prone to cracking after being bent multiple times by curved surfaces and bending equipment.

[0004] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0005] The object of the present invention is to provide an epoxy resin frame sealant, an adhesive film and a preparation method thereof. The epoxy resin frame sealant can be quickly cured at low temperature and has excellent storage stability at low temperature.

[0006] In order to achieve the above object, a technical solution provided by a specific embodiment of the present invention is as follows:

[0007] The epoxy resin frame sealing adhesive comprises the following raw materials in parts by weight: 20 to 30 parts of epoxy resin, 3 to 12 parts of polyether modified flexible epoxy resin, 5 to 30 parts of modified nitrile rubber, 13 to 25 parts of thiol curing agent, 5 to 25 parts of filler, 1 to 3 parts of accelerator, 0.1 to 0.5 parts of stabilizer, 1 to 5 parts of coupling agent, 3 to 10 parts of fumed silica and 0.1 to 0.5 parts of carbon black.

[0008] In one or more embodiments of the present invention, the epoxy resin is selected from alicyclic epoxy resins, aliphatic epoxy resins, bisphenol A epoxy resins, bisphenol F epoxy resins and linear phenolic epoxy resins.

[0009] In one or more embodiments of the present invention, the modified nitrile rubber is one or more of carboxyl-terminated nitrile rubber, hydroxyl-terminated nitrile rubber, amino-terminated nitrile rubber, epoxy-terminated nitrile rubber and vinyl-terminated nitrile rubber.

[0010] In one or more embodiments of the present invention, the thiol curing agent is selected from one or more of pentaerythritol tetrakis(3-mercaptopropionate), trihydroxypropane(3-mercaptopropionate), ethylene glycol di(3-mercaptopropionate), trimethylolpropane tris(2-mercaptopropionic acid), diethyl dimercaptoacetate, isooctyl mercaptoacetate, ethoxytrimethylolpropane tris(3-mercaptopropionate) and isooctyl mercaptopropionate.

[0011] In one or more embodiments of the present invention, the filler is one or more of talc, light calcium carbonate, silica powder, zinc oxide, aluminum oxide, boron nitride, and titanium dioxide.

[0012] In one or more embodiments of the present invention, the accelerator is one or both of a modified amine accelerator and a modified imidazole accelerator.

[0013] In one or more embodiments of the present invention, the coupling agent is one or more of 3-glycidyloxypropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, bis(γ-triethoxysilylpropyl)-tetrasulfide, phenyltrimethoxysilane, phenyltriethoxysilane, methyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane and γ-glycidyloxypropyltrimethoxysilane.

[0014] In one or more embodiments of the present invention, the stabilizer is malonyl urea.

[0015] Another specific embodiment of the present invention provides a technical solution as follows:

[0016] The preparation method of epoxy resin frame sealing adhesive comprises the following steps:

[0017] Mixing the mercaptan curing agent and the accelerator, stirring at 200 to 500 r / min for 30 to 60 minutes to obtain a first mixture;

[0018] Mixing epoxy resin, polyether modified flexible epoxy resin and modified nitrile rubber to obtain a second mixture;

[0019] The filler, stabilizer, coupling agent, fumed silica and carbon black are mixed, and then added to the second mixture, stirred at 300-500 r / min for 30-60 min, and then stirred at 800-2000 r / min for 2-4 h to obtain a third mixture;

[0020] When the temperature of the third mixture drops below 30° C., the first mixture is added and stirred at 300 to 500 r / min for 30 to 60 minutes to obtain the epoxy resin frame sealing adhesive.

[0021] Another specific embodiment of the present invention provides a technical solution as follows:

[0022] The adhesive film comprises a heavy release layer, an adhesive film layer and a light release layer which are stacked, and the adhesive film layer is formed by using the above-mentioned epoxy resin frame sealing adhesive or the epoxy resin frame sealing adhesive prepared by the above-mentioned preparation method.

[0023] Compared with the prior art, the epoxy resin frame sealant of the present invention fills the gap in the domestic flexible screen frame sealant, and has the advantages of rapid curing at low temperature, high bonding strength, moderate thermal expansion coefficient, and high water and oxygen barrier efficiency. The innovation is mainly reflected in the following points:

[0024] 1. The modified polythiol curing system is used in combination with a specially formulated epoxy resin and a certain amount of specific powder filler is added. It has the characteristics of high bonding strength, low thermal expansion coefficient and excellent flexibility.

[0025] 2. It solves the problem of cracking and deformation caused by traditional hard screen sealing glue in the existing foldable flexible screen sealing frame, and can also be used as flexible screen sealing glue that can be rolled up in the later stage, which can achieve multiple flexibility without deformation and cracking.

[0026] 3. Because it can be quickly cured at low temperature, has a simple process, excellent performance, and fully automated production, it replaces the traditional process that is prone to failure, complex, and cannot be fully automated, reducing production costs, improving production efficiency and reliability, and is safe to use. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0028] A specific embodiment of the present invention provides an epoxy resin frame sealing adhesive, comprising the following raw materials in parts by weight: 20 to 30 parts of epoxy resin, 3 to 12 parts of polyether modified flexible epoxy resin, 5 to 30 parts of modified nitrile rubber, 13 to 25 parts of thiol curing agent, 5 to 25 parts of filler, 1 to 3 parts of accelerator, 0.1 to 0.5 parts of stabilizer, 1 to 5 parts of coupling agent, 3 to 10 parts of fumed silica, and 0.1 to 0.5 parts of carbon black.

[0029] Specifically, the epoxy resin is selected from alicyclic epoxy resin, aliphatic epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin and linear phenolic epoxy resin. The epoxy resin can give the frame sealant better hardness and bonding strength, and at the same time can also improve the sealing performance of the frame sealant. The polyether-modified flexible epoxy resin is a flexible oligomeric epoxy resin modified by polyether polyols. By introducing polyether segments, the flexibility and ductility of the frame sealant can be improved, and the deformability can be increased, thereby improving the crack resistance of the frame sealant. Modified nitrile rubber specifically refers to rubber particles containing terminal active groups. During the curing process of the frame sealant, the active groups at the ends of the rubber particles can react with the epoxy resin reaction groups to generate flexible chain blocks, relying on chemical bonding to improve the ability of the frame sealant to resist external impacts, thereby reducing the possibility of cracking.

[0030] Furthermore, the thiol curing agent can accelerate the curing speed of the frame sealant, and the sulfur-containing flexible chain segment can improve the toughness of the frame sealant; the accelerator not only plays a catalytic role in the curing process of the frame sealant, but also decomposes itself at a certain temperature. The decomposition products can catalyze the curing reaction of the epoxy resin and can also be combined into the structure of the cured product to become a part of the cured product, thereby improving the performance of the frame sealant.

[0031] Furthermore, commercially available epoxy resin products may include Nan Ya 128, Changchun Chemical 188EL, and Changchun Chemical 518; commercially available polyether-modified flexible epoxy resin products may include Maoming Polykey New Materials EP-320 and Aidico EP-4000.

[0032] In a specific embodiment, the modified nitrile rubber is one or more of carboxyl-terminated nitrile rubber, hydroxyl-terminated nitrile rubber, amino-terminated nitrile rubber, epoxy-terminated nitrile rubber and vinyl-terminated nitrile rubber.

[0033] Specifically, the above types of modified nitrile rubber are selected, and the flexibility and bonding strength of the frame sealant are improved by utilizing the reaction of carboxyl, hydroxyl, amino, epoxy or vinyl with epoxy resin. At the same time, the crosslinking density of the frame sealant can be increased, and the barrier performance to water vapor can be improved. In terms of toughening raw materials, the three-dimensional stress field in the crack block of the material destroys the rubber particle / matrix interface and generates micropores. These pores can relieve the three-dimensional stress accumulated at the crack tip on the one hand, and induce local shear yield of the matrix between adjacent particles due to the stress concentration on the equator of the rubber particles on the other hand, thereby achieving the purpose of toughening.

[0034] Commercially available products of modified nitrile rubber include American Zeon 1072, American Zeon 1072CG, Japanese 3350X, American DN631, and Japanese N3d.

[0035] In a specific embodiment, the mercaptan curing agent is selected from one or more of tetrakis(3-mercaptopropionic acid) pentaerythritol ester, trihydroxypropane(3-mercaptopropionic acid ester), di(3-mercaptopropionic acid) ethylene glycol ester, trimethylolpropane tris(2-mercaptopropionic acid), diethyl dimercaptoacetate, isooctyl mercaptoacetate, ethoxy trimethylolpropane tris(3-mercaptopropionic acid) ester and isooctyl mercaptopropionic acid. Preferably, the mercaptan curing agent selects a polythiol curing agent.

[0036] Specifically, commercially available mercaptan curing agent products include Showa Denko PE1, Ho Sheng Chemical PEMP, Ho Sheng Chemical TMMP, Showa Denko TEMPIC, Showa Denko DPMP, Ho Sheng Chemical EGMP-4, Ho Sheng Chemical Thiol 308, and Zhuoban Chemical PE-6640.

[0037] In a specific embodiment, the filler is one or more of talc, light calcium carbonate, silicon powder, zinc oxide, aluminum oxide, boron nitride, and titanium dioxide.

[0038] Specifically, the above types of fillers are selected to play the role of reinforcement, coloring, corrosion protection, toughening, reducing shrinkage, reducing linear expansion coefficient, reducing internal stress, effectively preventing cracking, reducing exothermic temperature during curing, increasing thermal conductivity and thixotropy, and can also improve water resistance and aging resistance, extend the trial period of the frame sealant, and reduce ingredients. In addition, in order to prevent the liquid crystal box from shorting in the vertical and horizontal directions in practical applications, the filler cannot contain conductive particles. The particle size of the filler is preferably controlled within 5μm. Further preferably, the filler is selected from silicon micropowder and alumina, and more preferably, the filler is selected from silicon micropowder and alumina with a particle size less than 5μm.

[0039] In a specific embodiment, the accelerator is one or both of a modified amine accelerator and a modified imidazole accelerator.

[0040] Specifically, commercially available accelerator products include Japanese Ajinomoto PN-23, Japanese Ajinomoto PN-H, Japanese Ajinomoto MY-24, Guangzhou Guyan Electronics 100A, Guangzhou Guyan Electronics 100B, Japanese Fuji Chemical FXR-1020, and Japanese Fuji Chemical FXR-1081.

[0041] In a specific embodiment, the coupling agent is one or more of 3-glycidyloxypropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, bis(γ-triethoxysilylpropyl)-tetrasulfide, phenyltrimethoxysilane, phenyltriethoxysilane, methyltriethoxysilane, γ-(2,3-epoxypropyloxy)propyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane and γ-glycidyloxypropyltrimethoxysilane.

[0042] Specifically, the above-mentioned coupling agents can improve the bonding performance of the frame sealant, and the flexibility, water resistance and impact resistance of the frame sealant can be improved by introducing organic silicon molecular segments.

[0043] In one embodiment, the stabilizer is malonyl urea.

[0044] Specifically, malonyl urea can improve the stability of the frame sealant and reduce the possibility of early curing or performance changes during storage and use.

[0045] In one specific embodiment, the fumed silica is preferably silane-modified fumed silica.

[0046] Specifically, adding fumed silica to epoxy resin can improve the toughness and ductility of epoxy resin. After being modified with silane, fumed silica can form a strong interface bond with epoxy resin, thereby further promoting the dispersion of fumed silica in the system and better improving the performance of the frame sealant. Specifically, commercially available products can be Evonik R202, Evonik R972, Wacker H15, and Wacker H18.

[0047] In one embodiment, the carbon black is insulating carbon black.

[0048] Specifically, selecting insulating carbon black can improve the insulation performance of the frame sealing adhesive, prevent short circuits, and also improve the weather resistance of the frame sealing adhesive.

[0049] Another specific embodiment of the present invention provides a method for preparing epoxy resin frame sealing adhesive, comprising the following steps 1-4.

[0050] Step 1: Mix the mercaptan curing agent and the accelerator, and stir at 200 to 500 r / min for 30 to 60 minutes to obtain a first mixture.

[0051] Specifically, stirring the mercaptan curing agent and the accelerator at a lower speed to mix them can reduce the possibility of powder splashing during the stirring process.

[0052] Step 2, mixing epoxy resin, polyether modified flexible epoxy resin and modified nitrile rubber to obtain a second mixture;

[0053] Step 3, mix the filler, promoter, stabilizer, coupling agent, fumed silica and carbon black, then add them to the second mixture, stir at 300-500 r / min for 30-60 min, and then stir at 800-2000 r / min for 2-4 h to obtain a third mixture.

[0054] Step 4: When the temperature of the third mixture drops below 30° C., add the first mixture and stir at 300 to 500 r / min for 30 to 60 minutes to obtain the epoxy resin frame sealant.

[0055] Specifically, the third mixture generates heat during the stirring process, and the temperature rises to 40-80°C. When the temperature drops below 30°C, the first mixture is added to prevent the frame sealant from solidifying at a higher temperature. In addition, the first mixture and the third mixture are prepared separately, and then the first mixture and the third mixture are mixed. Since the amount of the first mixture is relatively small in the system, the first mixture can be dispersed in the third mixture more quickly during mixing.

[0056] Another specific embodiment of the present invention provides an adhesive film, comprising a heavy release layer, an adhesive film layer and a light release layer stacked together, wherein the adhesive film layer is formed by the above-mentioned epoxy resin frame sealing adhesive or the epoxy resin frame sealing adhesive prepared by the above-mentioned preparation method.

[0057] Specifically, according to actual application requirements, the frame sealing glue can be pre-prepared into a film, and cured at a relatively low temperature of 50-80°C for a relatively short time of 3-5 minutes to form a film through preliminary pre-crosslinking. The prepared film is stored at -20°C and warmed up to room temperature for 4-12 hours before use. After being bonded to the substrate, it can be quickly shaped and packaged at a low temperature, which is more convenient to use.

[0058] The present invention is further described in detail below in conjunction with specific embodiments.

[0059] Example 1

[0060] Epoxy resin frame sealing glue, calculated by mass, the raw materials include 30 parts of Nan Ya 128 epoxy resin, 5 parts of Aidico EP-4000 polyether modified flexible epoxy resin, 15 parts of American Zeon 1072 modified nitrile rubber, 22 parts of Showa Denko PE1 thiol curing agent, 22 parts of alumina with a particle size of 2μm, 1 part of Japan Ajinomoto MY-24 accelerator, 0.2 parts of malonylurea, 1.6 parts of γ-glycidyloxypropyltrimethoxysilane, 3 parts of Wacker H15 fumed silica, and 0.2 parts of carbon black.

[0061] During preparation, mix the accelerator and the thiol curing agent, stir at 200r / min for 30min to obtain the first mixture. Mix epoxy resin, polyether modified flexible epoxy resin and modified nitrile rubber, stir at 200r / min for 30min to obtain the second mixture. Mix alumina, malonylurea, γ-glycidyloxypropyltrimethoxysilane, fumed silica and carbon black and add them to the second mixture, first stir at 300r / min for 30min, then stir at 800r / min for 2h to obtain the third mixture. When the temperature of the third mixture drops below 30°C, add the first mixture to the third mixture, stir at 300r / min for 60min, and then obtain the epoxy resin frame sealant.

[0062] The prepared epoxy resin frame sealant was coated on the PET heavy release film by a slit coater, cured at 50°C for 3 minutes to form a film layer, and then a PET light release film was compounded on the film layer to obtain a film. The film was stored at -20°C and warmed up at room temperature for 4 hours before use.

[0063] Example 2

[0064] Epoxy resin frame sealing glue, calculated by mass, the raw materials include 27 parts of Changchun Chemical 188EL epoxy resin, 7 parts of Maoming Polybond New Material EP-320 polyether modified flexible epoxy resin, 10 parts of Japan 3350X modified nitrile rubber, 22 parts of Hesheng Chemical PEMP thiol curing agent, 25 parts of silica powder with a particle size of 1μm, 1 part of Japan Ajinomoto PN-23 accelerator, 0.1 part of malonylurea, 2.6 parts of γ-methacryloyloxypropyltrimethoxysilane, 5 parts of Wacker H18 fumed silica, and 0.3 part of carbon black.

[0065] During preparation, mix the accelerator and the thiol curing agent, stir at 300r / min for 30min to obtain the first mixture. Mix epoxy resin, polyether modified flexible epoxy resin and modified nitrile rubber, stir at 300r / min for 30min to obtain the second mixture. Mix silicon micropowder, malonylurea, γ-methacryloxypropyltrimethoxysilane, fumed silica and carbon black and add them to the second mixture, first stir at 400r / min for 40min, then stir at 1000r / min for 2h to obtain the third mixture. When the temperature of the third mixture drops below 30°C, add the first mixture to the third mixture, stir at 400r / min for 60min, and then obtain the epoxy resin frame sealant.

[0066] The prepared epoxy resin frame sealant was coated on the PET heavy release film by a slit coater, cured at 50°C for 3 minutes to form a film layer, and then a PET light release film was compounded on the film layer to obtain a film. The film was stored at -20°C and warmed up at room temperature for 4 hours before use.

[0067] Example 3

[0068] Epoxy resin frame sealing glue, calculated by mass, the raw materials include 28 parts of Changchun Chemical 188EL epoxy resin, 10 parts of Aidico EP-4000 polyether modified flexible epoxy resin, 10 parts of American DN631 modified nitrile rubber, 18 parts of Hesheng Chemical PEMP thiol curing agent, 22 parts of alumina with a particle size of 1μm, 1.8 parts of Japan Ajinomoto PN-23 accelerator, 0.2 parts of malonylurea, 3.5 parts of γ-glycidyloxypropyltrimethoxysilane, 6 parts of Wacker H15 fumed silica, and 0.5 parts of carbon black.

[0069] During preparation, mix the accelerator and the thiol curing agent, stir at 500r / min for 30min to obtain the first mixture. Mix epoxy resin, polyether modified flexible epoxy resin and modified nitrile rubber, stir at 500r / min for 30min to obtain the second mixture. Mix alumina, malonylurea, γ-glycidyloxypropyltrimethoxysilane, fumed silica and carbon black and add them to the second mixture, first stir at 500r / min for 40min, then stir at 2000r / min for 2h to obtain the third mixture. When the temperature of the third mixture drops below 30°C, add the first mixture to the third mixture and stir at 500r / min for 60min. After completion, the epoxy resin frame sealant is obtained.

[0070] The prepared epoxy resin frame sealant was coated on the PET heavy release film by a slit coater, cured at 50°C for 3 minutes to form a film layer, and then a PET light release film was compounded on the film layer to obtain a film. The film was stored at -20°C and warmed up at room temperature for 4 hours before use.

[0071] Example 4

[0072] Epoxy resin frame sealing glue, calculated by mass, the raw materials include 25 parts of Nan Ya 128 epoxy resin, 5 parts of Maoming Polybond New Material EP-320 polyether modified flexible epoxy resin, 15 parts of American Zeon 1072 modified nitrile rubber, 11 parts of Hesheng Chemical TMMP thiol curing agent, 10 parts of Showa Denko DPMP thiol curing agent, 25 parts of alumina with a particle size of 2μm, 1 part of Japan Ajinomoto PN-23 accelerator, 0.1 part of malonylurea, 2.7 parts of γ-glycidyloxypropyltrimethoxysilane, 5 parts of Evonik R202 fumed silica, and 0.2 part of carbon black.

[0073] During preparation, mix the accelerator and the thiol curing agent, stir at 200r / min for 30min to obtain the first mixture. Mix epoxy resin, polyether modified flexible epoxy resin and modified nitrile rubber, stir at 200r / min for 30min to obtain the second mixture. Mix alumina, malonylurea, γ-glycidyloxypropyltrimethoxysilane, fumed silica and carbon black and add them to the second mixture, first stir at 300r / min for 30min, then stir at 800r / min for 2h to obtain the third mixture. When the temperature of the third mixture drops below 30°C, add the first mixture to the third mixture, stir at 300r / min for 60min, and then obtain the epoxy resin frame sealant.

[0074] The prepared epoxy resin frame sealant was coated on the PET heavy release film by a slit coater, cured at 50°C for 3 minutes to form a film layer, and then a PET light release film was compounded on the film layer to obtain a film. The film was stored at -20°C and warmed up at room temperature for 4 hours before use.

[0075] Example 5

[0076] Epoxy resin frame sealing glue, calculated by mass, the raw materials include 30 parts of Changchun Chemical 188EL epoxy resin, 10 parts of Aidico EP-4000 polyether modified flexible epoxy resin, 10 parts of American Zeon 1072CG modified nitrile rubber, 24 parts of Hesheng Chemical Thiol 308 thiol curing agent, 18 parts of silicon micropowder with a particle size of 1μm, 2 parts of Japan Ajinomoto PN-23 accelerator, 0.2 parts of malonylurea, 2.5 parts of γ-methacryloxypropyltrimethoxysilane, 3 parts of Evonik R202 fumed silica, and 0.3 parts of carbon black.

[0077] During preparation, mix the accelerator and the thiol curing agent, stir at 200r / min for 30min to obtain the first mixture. Mix epoxy resin, polyether modified flexible epoxy resin and modified nitrile rubber, stir at 200r / min for 30min to obtain the second mixture. Mix silicon micropowder, malonylurea, γ-methacryloxypropyltrimethoxysilane, fumed silica and carbon black and add them to the second mixture, first stir at 300r / min for 30min, then stir at 800r / min for 2h to obtain the third mixture. When the temperature of the third mixture drops below 30°C, add the first mixture to the third mixture and stir at 300r / min for 60min. After completion, the epoxy resin frame sealant is obtained.

[0078] The prepared epoxy resin frame sealant was coated on the PET heavy release film by a slit coater, cured at 50°C for 3 minutes to form a film layer, and then a PET light release film was compounded on the film layer to obtain a film. The film was stored at -20°C and warmed up at room temperature for 4 hours before use.

[0079] Example 6

[0080] Epoxy resin frame sealing glue, calculated by mass, the raw materials include 28 parts of Changchun Chemical 518 epoxy resin, 12 parts of Maoming Polybond New Material EP-320 polyether modified flexible epoxy resin, 15 parts of Japan 3350X modified nitrile rubber, 20 parts of Zhuoben Chemical polythiol PE-6640 thiol curing agent, 15 parts of silicon micropowder with a particle size of 1μm, 2 parts of Japan Ajinomoto MY-24 accelerator, 0.2 parts of malonylurea, 3.5 parts of γ-glycidyloxypropyltrimethoxysilane, 4 parts of Wacker H15 fumed silica, and 0.3 parts of carbon black.

[0081] During preparation, the accelerator and the thiol curing agent are mixed, stirred at 200r / min for 30min to obtain the first mixture. The epoxy resin, polyether-modified flexible epoxy resin and modified nitrile rubber are mixed, stirred at 200r / min for 30min to obtain the second mixture. Silica powder, malonylurea, γ-glycidyloxypropyltrimethoxysilane, fumed silica and carbon black are mixed and added to the second mixture, first stirred at 300r / min for 30min, and then stirred at 800r / min for 2h to obtain the third mixture. When the temperature of the third mixture drops below 30°C, the first mixture is added to the third mixture, stirred at 300r / min for 60min, and the epoxy resin frame sealant is obtained after the end.

[0082] The prepared epoxy resin frame sealant was coated on the PET heavy release film by a slit coater, cured at 50°C for 3 minutes to form a film layer, and then a PET light release film was compounded on the film layer to obtain a film. The film was stored at -20°C and warmed up at room temperature for 4 hours before use.

[0083] Comparative Example 1

[0084] Epoxy resin frame sealing glue, calculated by mass, the raw materials include 30 parts of Nan Ya 128 epoxy resin, 15 parts of Adec EP-4000 polyether modified flexible epoxy resin, 24 parts of Showa Denko PE1 thiol curing agent, 20 parts of silicon micropowder with a particle size of 1μm, 2 parts of Japan Ajinomoto MY-24 accelerator, 0.2 parts of malonylurea, 2.5 parts of γ-glycidyloxypropyltrimethoxysilane, 6 parts of Wacker H18 fumed silica, and 0.3 parts of carbon black.

[0085] During preparation, mix the accelerator and the thiol curing agent, stir at 200r / min for 30min to obtain the first mixture. Mix the epoxy resin and the polyether modified flexible epoxy resin, stir at 200r / min for 30min to obtain the second mixture. Mix silicon micropowder, malonylurea, γ-glycidyloxypropyltrimethoxysilane, fumed silica and carbon black, first stir at 300r / min for 30min, then stir at 800r / min for 2h to obtain the third mixture. When the temperature of the third mixture drops below 30°C, add the first mixture to the third mixture, stir at 300r / min for 60min, and then obtain the epoxy resin frame sealant.

[0086] The prepared epoxy resin frame sealant was coated on the PET heavy release film by a slit coater, cured at 50°C for 3 minutes to form a film layer, and then a PET light release film was compounded on the film layer to obtain a film. The film was stored at -20°C and warmed up at room temperature for 4 hours before use.

[0087] Comparative Example 2

[0088] Epoxy resin frame sealing glue, calculated by mass, the raw materials include 28 parts of Changchun Chemical 188EL epoxy resin, 20 parts of Maoming Polybond New Material EP-320 polyether modified flexible epoxy resin, 22 parts of Hesheng Chemical PEMP thiol curing agent, 18 parts of 2μm aluminum oxide, 2 parts of Japan Ajinomoto PN-23 accelerator, 0.2 parts of malonylurea, 3.5 parts of γ-methacryloxypropyltrimethoxysilane, 6 parts of Evonik R202 fumed silica, and 0.3 parts of carbon black.

[0089] During preparation, mix the accelerator and the thiol curing agent, stir at 200r / min for 30min to obtain the first mixture. Mix the epoxy resin and the polyether modified flexible epoxy resin, stir at 200r / min for 30min to obtain the second mixture. Mix alumina, malonylurea, γ-glycidyloxypropyltrimethoxysilane, fumed silica and carbon black, first stir at 300r / min for 30min, then stir at 800r / min for 2h to obtain the third mixture. When the temperature of the third mixture drops below 30°C, add the first mixture to the third mixture, stir at 300r / min for 60min, and then obtain the epoxy resin frame sealant.

[0090] The prepared epoxy resin frame sealant was coated on the PET heavy release film by a slit coater, cured at 50°C for 3 minutes to form a film layer, and then a PET light release film was compounded on the film layer to obtain a film. The film was stored at -20°C and warmed up at room temperature for 4 hours before use.

[0091] Comparative Example 3

[0092] Epoxy resin frame sealing glue, calculated by mass, the raw materials include 28 parts of Nan Ya 128 epoxy resin, 7 parts of Aidico EP-4000 polyether modified flexible epoxy resin, 13 parts of American Zeon 1072 modified nitrile rubber, 23 parts of Showa Denko PE1 thiol curing agent, 22 parts of alumina with a particle size of 2μm, 0.2 parts of malonylurea, 1.6 parts of γ-glycidyloxypropyltrimethoxysilane, 3 parts of Wacker H15 fumed silica, and 0.2 parts of carbon black.

[0093] During preparation, epoxy resin, polyether modified flexible epoxy resin and modified nitrile rubber are mixed and stirred at 200r / min for 30min to obtain the first mixture. Alumina, malonylurea, γ-glycidyloxypropyltrimethoxysilane, fumed silica and carbon black are mixed and added to the first mixture, first stirred at 300r / min for 30min, then stirred at 800r / min for 2h to obtain the second mixture. When the temperature of the second mixture drops below 30°C, the thiol curing agent is added to the second mixture and stirred at 300r / min for 60min to obtain the epoxy resin frame sealant.

[0094] The prepared epoxy resin frame sealant was coated on the PET heavy release film by a slit coater, cured at 50°C for 3 minutes to form a film layer, and then a PET light release film was compounded on the film layer to obtain a film. The film was stored at -20°C and warmed up at room temperature for 4 hours before use.

[0095] Performance Testing

[0096] Storage stability test: Place the frame glue in a 10°C environment and measure the viscosity change after 30 days. If the change rate is less than 10%, the storage stability is good; if the change rate is 11-50%, there are minor problems with storage stability; if the change rate exceeds 50%, the storage stability is poor. After testing, the viscosity change rate of the frame glue in Examples 1-6 is less than 10%, and the storage stability is good; the viscosity change rate of the frame glue in Comparative Examples 1-3 exceeds 50%, and the storage stability is poor.

[0097] The frame sealant was coated onto the smooth anti-adhesive film with a thickness of 70-120 μm, pre-baked at 80°C for 4-6 minutes, and then cured at 150°C for 60 minutes to obtain a cured film. The cured film was subjected to the following tests:

[0098] (1) Heat deformation temperature of cured product: The frame glue is coated on a smooth anti-adhesive film with a thickness of 70 to 120 μm, and pre-baked at 80°C for 4 to 6 minutes, and then cured at 150°C for 60 minutes to obtain a cured film. The heat deformation temperature of the cured product is determined by TMA test (thermomechanical analysis). If the heat deformation temperature is higher than 100°C, it meets the performance requirements of the frame glue for liquid crystal. After testing, the frame glues in Examples 1-6 all meet the requirements, while Comparative Examples 1-3 do not meet the requirements.

[0099] (2) Thermal expansion coefficient of the cured product: The thermal expansion coefficient of the cured product is tested using TMA, and the thermal expansion coefficient of the sample is recorded before and after the glass transition temperature (Tg). The thermal expansion coefficient of the cured product is less than 6×105mm / (mm / ℃), which meets the performance requirements of the border glue for liquid crystal.

[0100] (3) Water absorption of the cured product: The cured film was immersed in boiling water for 3 hours, and then the weight gain was measured. Water absorption (%) = (weight gain after immersion in boiling water / weight before the test) × 100. If the water absorption is less than 0.4%, it indicates that the cured product has low moisture permeability.

[0101] (4) Flexibility test: The cured film is placed on a special flexibility test fixture and subjected to 100,000 cycles of flexibility test to observe whether there are cracks at the bending position. If there are no cracks, the flexibility is good; if there are cracks, the flexibility is poor.

[0102] (5) Water boiling resistance of the cured product: The glass with the printed frame sealant was placed in an 80°C furnace for pre-baking for 4 to 6 minutes. The glass glued together was then placed in a high-temperature furnace, heated to 150°C, and pressurized to 1 kg / cm 2 After the laminated and cured glass is filled with liquid crystal to make a liquid crystal screen, the liquid crystal screen is placed in boiling water for 50 hours. If there is no leakage of liquid crystal, the water boiling resistance is good; if there is leakage of liquid crystal, the water boiling resistance is poor.

[0103] Table 1 Performance test results

[0104]

[0105]

[0106] It can be seen from Table 1 that, compared with Comparative Examples 1-3, although the curing time of the frame sealant in the embodiment of the present invention is slightly longer, it is also less than 20 minutes to meet the process requirements. The glass transition temperature, linear expansion coefficient and water absorption rate of the frame sealant in the embodiment are lower, and it exhibits better toughness, water vapor barrier performance and flexibility resistance, and can meet the application requirements of flexible and bendable scenes.

[0107] 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 present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0108] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An epoxy resin frame sealant, characterized in that: The invention comprises the following raw materials in parts by weight: 20 to 30 parts of epoxy resin, 3 to 12 parts of polyether modified flexible epoxy resin, 5 to 30 parts of modified nitrile rubber, 13 to 25 parts of thiol curing agent, 5 to 25 parts of filler, 1 to 3 parts of accelerator, 0.1 to 0.5 parts of stabilizer, 1 to 5 parts of coupling agent, 3 to 10 parts of fumed silica and 0.1 to 0.5 parts of carbon black.

2. The epoxy resin frame sealant according to claim 1, characterized in that: The epoxy resin is selected from alicyclic epoxy resin, aliphatic epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin and linear phenolic epoxy resin.

3. The epoxy resin frame sealant according to claim 1, characterized in that: The modified nitrile rubber is one or more of carboxyl-terminated nitrile rubber, hydroxyl-terminated nitrile rubber, amino-terminated nitrile rubber, epoxy-terminated nitrile rubber and vinyl-terminated nitrile rubber.

4. The epoxy resin frame sealant according to claim 1, characterized in that: The thiol curing agent is selected from one or more of pentaerythritol tetrakis(3-mercaptopropionate), trihydroxypropane (3-mercaptopropionate), ethylene glycol di(3-mercaptopropionate), trimethylolpropane tris(2-mercaptopropionic acid), diethyl dimercaptoacetate, isooctyl mercaptoacetate, ethoxytrimethylolpropane tris(3-mercaptopropionate) and isooctyl mercaptopropionate.

5. The epoxy resin frame sealant according to claim 1, characterized in that: The filler is one or more of talc, light calcium carbonate, silicon powder, zinc oxide, aluminum oxide, boron nitride and titanium dioxide.

6. The epoxy resin frame sealant according to claim 1, characterized in that: The accelerator is one or both of a modified amine accelerator and a modified imidazole accelerator.

7. The epoxy resin frame sealant according to claim 1, characterized in that: The coupling agent is one or more of 3-glycidyloxypropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, bis(γ-triethoxysilylpropyl)-tetrasulfide, phenyltrimethoxysilane, phenyltriethoxysilane, methyltriethoxysilane, γ-(2,3-epoxypropyloxy)propyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane and γ-glycidyloxypropyltrimethoxysilane.

8. The epoxy resin frame sealant according to claim 1, characterized in that: The stabilizer is malonyl urea.

9. A method for preparing the epoxy resin frame sealant according to any one of claims 1 to 8, characterized in that: The steps include: Mixing the mercaptan curing agent and the accelerator, stirring at 200 to 500 r / min for 30 to 60 minutes to obtain a first mixture; Mixing epoxy resin, polyether modified flexible epoxy resin and modified nitrile rubber to obtain a second mixture; The filler, stabilizer, coupling agent, fumed silica and carbon black are mixed, and then added to the second mixture, stirred at 300-500 r / min for 30-60 min, and then stirred at 800-2000 r / min for 2-4 h to obtain a third mixture; When the temperature of the third mixture drops below 30° C., the first mixture is added and stirred at 300 to 500 r / min for 30 to 60 minutes to obtain the epoxy resin frame sealing adhesive.

10. An adhesive film, characterized in that: It comprises a heavy release layer, a film layer and a light release layer which are stacked, wherein the film layer is formed by the epoxy resin frame sealing adhesive according to any one of claims 1 to 8 or the epoxy resin frame sealing adhesive prepared by the preparation method according to claim 9.

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