Micro LED display module packaging adhesive film and preparation method thereof

Abstract

The invention discloses a Micro LED display module packaging adhesive film and a preparation method thereof. The Micro LED display module packaging adhesive film comprises a first release film layer, an epoxy adhesive film layer and a second release film layer which are sequentially laminated, the epoxy adhesive film layer is prepared from the following raw material components in parts by weight: 100 parts of solid epoxy resin, 5 to 20 parts of liquid epoxy resin, 5 to 20 parts of toughening resin, 10 to 30 parts of carbon black filler, 1 to 20 parts of silicon dioxide, 1 to 10 parts of coupling agent, 2 to 10 parts of curing agent, 5 to 10 parts of accelerant, 0.1 to 2 parts of defoaming agent and 0.05 to 0.5 part of flatting agent. According to the Micro LED display module packaging adhesive film disclosed by the invention, the release film, the toughening resin, the accelerant and the like are regulated and controlled, so that the obtained packaging adhesive film can meet the requirements of high infiltration, high filling property, high adhesion, long-term aging resistance, excellent mechanical strength and low warping property, the operation process is simple and convenient, and continuous production can be realized.

Description

Technical Field

[0001] This invention relates to the field of Micro LED packaging technology, specifically to a Micro LED display module encapsulation film and its preparation method. Background Technology

[0002] Micro LED (micro light-emitting diode) is considered the ultimate solution for next-generation display technology. Its core concept is to shrink the size of traditional LED display devices to the micrometer level (usually less than 50 micrometers) and integrate them into a high-density pixel array to achieve self-emissive display. It has advantages such as extremely high brightness, no need for backlighting, high photoelectric conversion efficiency, extremely fast response time, and unlimited application forms. It is a revolutionary process of thinning, miniaturizing, and arraying traditional LEDs.

[0003] The packaging process is a crucial core step in the manufacturing of Micro LED display technology. Since Micro LED chips are typically smaller than 50 μm, after mass transfer, the encapsulating film must ensure high precision and bubble-free filling between millions or even tens of millions of micron-sized chips, while effectively protecting the extremely fine electrode structures. Traditional through-hole and surface-mount (SMT) packaging methods can no longer meet the packaging requirements of Micro LEDs. Currently, commonly used Micro LED packaging methods include Chip-type SMD packaging, N-in-one IMD packaging, and COB packaging. COB packaging offers the highest integration density, theoretically achieving the smallest pixel pitch, highest reliability, and longest display lifespan, making it the optimal packaging solution for Micro LEDs.

[0004] The mainstream COG encapsulation materials are mainly silicone resin, polyurethane resin, and epoxy resin. Silicone resin has poor adhesion, requiring an additional primer, which increases process complexity and the risk of interface failure. Furthermore, its loose molecular structure makes it less effective at blocking water, oxygen, and sulfides than epoxy resin. Polyurethane resin, on the other hand, lacks sufficient heat resistance and aging resistance. Its urethane and ester bonds are prone to hydrolysis and yellowing under humid, hot, and ultraviolet conditions, making it difficult to meet the long lifespan requirements of tens of thousands of hours for Micro LEDs, which is unacceptable for applications such as outdoor displays. Epoxy resin, with its high mechanical strength and moisture barrier properties, extremely high adhesive strength and interface reliability, excellent mechanical strength, and low warpage, has become a high-performance encapsulation material surpassing silicone and polyurethane resins. At the same time, epoxy resin films can meet the requirements of key process technologies such as mass transfer and thermo-compression bonding, making it an ideal material for Micro LED encapsulation.

[0005] Currently, commonly used epoxy encapsulation films on the market include solid epoxy, liquid epoxy, organosilane-modified epoxy, and UV-curable epoxy. However, in practical applications, they still face problems such as insufficient heat resistance, insufficient long-term reliability, complex processes, or high curing temperatures, long curing times, and high costs (e.g., liquid epoxy CN 119371919 A, organosilane-modified epoxy CN 117363242 A, and UV-curable dual-curing CN 222684545U). Especially after the mass transfer of Micro LEDs, the encapsulation film needs to ensure high precision and bubble-free filling between millions or even tens of millions of micron-sized chips, and effectively protect the extremely fine electrode structure. Under these stringent requirements, how to provide a Micro LED encapsulation film that combines high adhesive strength, good filling and wetting properties, long-term high reliability, and good processability has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing a Micro LED display module encapsulation film and its preparation method, which can meet the requirements of high wetting and filling properties, high adhesion, long-term aging resistance, excellent mechanical strength and low warpage, and the operation process is simple and convenient and can be continuously produced.

[0007] To address the aforementioned technical problems, this invention provides a Micro LED display module encapsulation film, comprising a first release film layer, an epoxy film layer, and a second release film layer sequentially stacked. By weight, the epoxy film layer comprises the following raw material components: 100 parts solid epoxy resin, 5-20 parts liquid epoxy resin, 5-20 parts toughening resin, 10-30 parts carbon black filler, 1-20 parts silica, 1-10 parts coupling agent, 2-10 parts curing agent, 5-10 parts accelerator, 0.1-2 parts defoamer, and 0.05-0.5 parts leveling agent.

[0008] This invention utilizes solid epoxy resin to provide mechanical strength, liquid epoxy resin to provide flowability and filling properties, and a toughening resin that has undergone carboxylation modification. The carboxyl groups on the resin, catalyzed by an accelerator, undergo a curing reaction with epoxy groups at a medium temperature (80℃-120℃) to form a network structure. Combined with the synergistic effect of the curing agent, this achieves curing at a lower curing temperature and in a shorter curing time. Carbon black filler provides color coverage, nano-silica reduces the overall CTE of the film, and a silane coupling agent improves the compatibility between the inorganic filler and the epoxy resin. For example, the mechanism by which tertiary amines (accelerators) promote the reaction between carboxyl and epoxy groups is as follows:

[0009] The tertiary amine first forms an ion pair (ammonium carboxylate) with the carboxylic acid, which greatly enhances the acidity of the carboxylic acid proton, making it more readily dissociable. The activated carboxylate anion then attacks the β-carbon atom of the epoxide group via nucleophilic attack, causing ring opening and forming an ester bond and a new alkoxy anion. This alkoxy anion rapidly abstracts a proton from another carboxylic acid molecule, generating an alcohol hydroxyl group and regenerating the carboxylate anion, continuing the chain reaction. This process significantly lowers the activation energy of the reaction, allowing it to proceed rapidly at intermediate temperatures (80℃-120℃).

[0010] Furthermore, the solid epoxy resin is selected from one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, hydrogenated bisphenol A epoxy resin, and aliphatic epoxy resin. Preferably, the solid epoxy resin is a bisphenol A type epoxy resin, such as Nanya bisphenol A epoxy resin NPES-901.

[0011] Furthermore, the liquid epoxy resin is one or more of the following: bisphenol A epoxy resin, bisphenol F epoxy resin, aliphatic glycidyl ether epoxy resin, phenolic epoxy resin, hydrogenated bisphenol A epoxy resin, reactive diluent epoxy resin, and diluent epoxy resin. Preferably, the liquid epoxy resin is a liquid bisphenol A epoxy resin or a diluent epoxy resin, such as Nanya BPA epoxy resin NPEL-127E and Nanya diluent epoxy resin NPEF-171.

[0012] The weight ratio of solid epoxy resin to liquid epoxy resin is 100:(5-20). When the content of solid epoxy resin is too high, the flowability of the epoxy film layer is poor, making it difficult to completely fill the gaps and cavities of the chip. When the content of liquid epoxy resin is too high, the initial tack of the epoxy film layer is high, and the flowability is excessive, which is not convenient for encapsulation operations and rework. At the same time, the overflow phenomenon is serious.

[0013] Furthermore, the toughening resin is selected from one or more of the following: nitrile rubber and its carboxyl-modified and epoxy-modified derivatives, phenoxy resin and its carboxyl-modified and epoxy-modified derivatives, acrylate rubber and its carboxyl-modified and epoxy-modified derivatives, and ethylene acrylate rubber and its carboxyl-modified and epoxy-modified derivatives. Preferably, the toughening resin is a carboxylated modified nitrile rubber, such as JSR's XER-32 or Huntsman's RK84L, or a phenoxy resin, such as Nippon Steel & Sumitomo Metal's YP50.

[0014] Furthermore, the coupling agent is one or more of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and 3-epoxypropoxypropyltrimethoxysilane. Preferably, it is 3-(2,3-epoxypropoxy)propyltrimethoxysilane, such as KH-560 (Chinese Academy of Sciences), A-187 (GE / OSi, USA), KBM-403 (Shin-Etsu Chemical Co., Ltd., Japan), and Z-6040 (Dow Corning, USA).

[0015] Furthermore, the curing agent is an anionic epoxy curing agent, selected from one or more of aliphatic amines, polyamides, aromatic amines, acid anhydrides, dicyandiamide, phenolic amines, thiols, and imidazoles. Preferably, the curing agent is dicyandiamide, acid anhydrides, or aromatic amines, such as dicyandiamide (DICY), 3,3'-diaminodiphenyl sulfone (DDS), or diaminodiphenylmethane (DDM).

[0016] Furthermore, the accelerator is selected from one or more of tertiary amines, imidazoles, organophosphorus compounds, transition metals, and phenols. Preferably, the accelerator is a tertiary amine or imidazole, such as 2-methylimidazolium (2-MI) or 1-cyanoethyl-2-ethyl-4-methylimidazolium (2E4MZ-CN). The reaction is initiated by the formation of a molecular complex between the imidazole or tertiary amine and the imino group (-NH-) on the curing agent dicyandiamide, which then dissociates to release an active species at a relatively low temperature.

[0017] Furthermore, the first release film layer is a light release film, and the second release film layer is a heavy release film. By adjusting the adhesion between the epoxy adhesive film layer and the second release film layer to a suitable range, the die-cutting process after molding of the traditional Micro LED encapsulation film is eliminated. By selecting a suitable second release film (heavy release film), good adhesion between the molded film and the substrate is ensured, and waste disposal of unbonded film is achieved without a die-cutting process.

[0018] Furthermore, the second release film layer is selected from one of silicone release film, non-silicone release film, and fluorine release film. Preferably, it is a non-silicone release film, wherein the release force of the 7475 test tape is 1000-2000 gf / inch, and the release force of the 31B test tape is 100-300 gf / inch.

[0019] Furthermore, the thickness of the first release film layer is 5~150μm, the thickness of the epoxy film layer is 5~150μm, and the thickness of the second release film layer is 5-70μm.

[0020] Furthermore, the leveling agent is a fluorocarbon leveling agent.

[0021] A second aspect of the present invention provides a method for preparing the encapsulating film for a Micro LED display module as described in the first aspect, comprising the following steps:

[0022] S1. A solid epoxy resin, a liquid epoxy resin, a toughening resin, carbon black filler, silica, a coupling agent, a curing agent, an accelerator, a defoamer, and a leveling agent are dispersed in an organic solvent to obtain an epoxy adhesive; wherein the organic solvent is one or more selected from butanone, acetone, cyclohexanone, ethyl acetate, butyl acetate, cyclohexane, methylcyclohexane, toluene, and N,N-dimethylformamide;

[0023] S2. The epoxy adhesive is applied to the second release film, dried and pre-cured (80℃-120℃) to form an epoxy film layer. After being combined with the first release film, the Micro LED display module encapsulation film is obtained.

[0024] The beneficial effects of this invention are:

[0025] The Micro LED display module encapsulation film provided by this invention does not require a die-cutting process during the encapsulation process. Compared with other films that require die-cutting after molding, this film can achieve die-cutting and waste removal of unbonded films without additional die-cutting process, while ensuring good adhesion between the film and the substrate during the molding process.

[0026] The accelerator in the formulation of this invention has a good catalytic effect on the curing reaction of both the added carboxyl-modified toughening resin and the curing agent with epoxy, thereby ensuring that the curing reaction of the film proceeds well at a lower curing temperature and a shorter curing time.

[0027] The adhesive film provided by this invention uses a specific ratio of solid epoxy resin and liquid epoxy resin, which has excellent fluidity, can achieve high filling of the bottom of the chip, excellent environmental reliability, resistance to thermal shock and solvent resistance, and the encapsulation process is simple and convenient, providing an efficient and stable solution for Micro-LED encapsulation. Attached Figure Description

[0028] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the encapsulation film structure for the Micro LED display module of the present invention. Detailed Implementation

[0030] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Reference Figure 1 As shown, this invention provides a Micro LED display module encapsulation film, comprising a first release film layer, an epoxy film layer, and a second release film layer stacked sequentially. By weight, the epoxy film layer comprises the following raw material components: 100 parts solid epoxy resin, 5-20 parts liquid epoxy resin, 5-20 parts toughening resin, 10-30 parts carbon black filler, 1-20 parts silica, 1-10 parts coupling agent, 2-10 parts curing agent, 5-10 parts accelerator, 0.1-2 parts defoamer, and 0.05-0.5 parts leveling agent. In this embodiment, solid epoxy resin provides mechanical strength, liquid epoxy resin provides flowability and filling properties, and the toughening resin undergoes carboxylation modification. The carboxyl groups on the resin, under the catalysis of the accelerator, undergo a curing reaction with epoxy groups at a medium temperature (80℃-120℃) to form a network structure. Combined with the synergistic effect of the curing agent, this achieves curing at a lower curing temperature and a shorter curing time. Carbon black filler provides color opacity, nano silica reduces the overall CTE of the film, and silane coupling agent improves the compatibility between inorganic filler and epoxy resin.

[0032] In a preferred embodiment, the solid epoxy resin is selected from one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, hydrogenated bisphenol A epoxy resin, and aliphatic epoxy resin. Preferably, the solid epoxy resin is a bisphenol A type epoxy resin, such as Nanya bisphenol A epoxy resin NPES-901.

[0033] In a preferred embodiment, the liquid epoxy resin is one or more of the following: bisphenol A epoxy resin, bisphenol F epoxy resin, aliphatic glycidyl ether epoxy resin, phenolic epoxy resin, hydrogenated bisphenol A epoxy resin, reactive diluent epoxy resin, and diluent epoxy resin. Preferably, the liquid epoxy resin is liquid bisphenol A epoxy resin or a diluent epoxy resin, such as Nanya BPA epoxy resin NPEL-127E and Nanya diluent epoxy resin NPEF-171. The weight ratio of solid epoxy resin to liquid epoxy resin is 100:(5-20). When the solid epoxy resin content is too high, the epoxy film layer has poor fluidity and is difficult to completely fill the gaps and cavities of the chip; when the liquid epoxy resin content is too high, the initial tack of the epoxy film layer is high, and the fluidity is excessive, which is not convenient for encapsulation operations and rework, and at the same time, the overflow phenomenon is serious.

[0034] In a preferred embodiment, the toughening resin is selected from one or more of the following: nitrile rubber and its carboxyl-modified and epoxy-modified derivatives, phenoxy resin and its carboxyl-modified and epoxy-modified derivatives, acrylate rubber and its carboxyl-modified and epoxy-modified derivatives, and ethylene acrylate rubber and its carboxyl-modified and epoxy-modified derivatives. Preferably, the toughening resin is a carboxylated modified nitrile rubber, such as JSR's XER-32 or Huntsman's RK84L, or a phenoxy resin, such as Nippon Steel & Sumitomo Metal's YP50.

[0035] In a preferred embodiment, the coupling agent is 3-(2,3-epoxypropoxy)propyltrimethoxysilane, such as KH-560 (Chinese Academy of Sciences), A-187 (GE / OSi, USA), KBM-403 (Shin-Etsu Chemical Co., Ltd., Japan), and Z-6040 (Dow Corning, USA). The leveling agent is a fluorocarbon type leveling agent.

[0036] In a preferred embodiment, the curing agent is an anionic epoxy curing agent, selected from one or more of aliphatic amines, polyamides, aromatic amines, acid anhydrides, dicyandiamide, phenolic amines, thiols, and imidazoles. Preferably, the curing agent is dicyandiamide, acid anhydrides, or aromatic amines, such as dicyandiamide (DICY), 3,3'-diaminodiphenyl sulfone (DDS), or diaminodiphenylmethane (DDM).

[0037] In a preferred embodiment, the accelerator is selected from one or more of tertiary amines, imidazoles, organophosphorus compounds, transition metals, and phenols. Preferably, the accelerator is a tertiary amine or imidazole, such as 2-methylimidazolium (2-MI) or 1-cyanoethyl-2-ethyl-4-methylimidazolium (2E4MZ-CN). The reaction is initiated by the formation of a molecular complex between the imidazole or tertiary amine and the imino group (-NH-) on the curing agent dicyandiamide, which then dissociates to release an active species at a relatively low temperature.

[0038] In a preferred embodiment, the first release film layer is a light release film, and the second release film layer is a heavy release film. By adjusting the adhesion between the epoxy adhesive film layer and the second release film layer to a suitable range, the die-cutting process after molding the traditional Micro LED encapsulation film is eliminated. By selecting a suitable second release film (heavy release film), good adhesion between the molded film and the substrate is ensured, and waste disposal of unbonded film is achieved without a die-cutting process. The second release film layer is selected from one of silicone release films, non-silicone release films, and fluorinated release films. Preferably, it is a non-silicone release film, wherein the release force of the 7475 test tape is 1000-2000 gf / inch, and the release force of the 31B test tape is 100-300 gf / inch. The thickness of the first release film layer is 5-150 μm, the thickness of the epoxy adhesive film layer is 5-150 μm, and the thickness of the second release film layer is 5-70 μm.

[0039] Another embodiment provides a method for preparing the encapsulating film for the Micro LED display module described in the above embodiments, comprising the following steps:

[0040] S1. A solid epoxy resin, a liquid epoxy resin, a toughening resin, carbon black filler, silica, a coupling agent, a curing agent, an accelerator, a defoamer, and a leveling agent are dispersed in an organic solvent to obtain an epoxy adhesive; wherein the organic solvent is one or more selected from butanone, acetone, cyclohexanone, ethyl acetate, butyl acetate, cyclohexane, methylcyclohexane, toluene, and N,N-dimethylformamide;

[0041] S2. The epoxy adhesive is applied to the second release film, dried and pre-cured (80℃-120℃) to form an epoxy film layer. After being combined with the first release film, the Micro LED display module encapsulation film is obtained.

[0042] The raw material components for preparing the encapsulating film for Micro LED display modules in Examples 1-4 and Comparative Examples 1-4 are as follows:

[0043] Solid epoxy resin: Nan Ya Bisphenol A Epoxy Resin NPES-901;

[0044] Liquid epoxy resins: Nan Ya BPA type epoxy resin NPEL-127E, Nan Ya diluted epoxy resin (diluted bisphenol F type epoxy resin, viscosity 500-300 (cps / 25℃), BPA / BPF mixed type) NPEF-171;

[0045] Toughening resins: JSR's carboxylated modified nitrile rubber XER-32 and Nippon Steel & Sumitomo Metal Corporation's phenoxy resin YP50S (average molecular weight 60,000, Tg 84℃).

[0046] Carbon black: DENKA BLACK Li from DENKA Denka Co., Ltd.;

[0047] Silica: Evonik Chemical's R202;

[0048] Coupling agent: KBM-403 from Shin-Etsu Chemical Co., Ltd., Japan;

[0049] Curing agent: Commercially available dicyandiamide (DICY);

[0050] Accelerator: Imidazole accelerator 2E4MZ-CN from Shikoku Chemical Co., Ltd., Japan;

[0051] Defoamer: Haiming Sideqian's modified polysiloxane DEFOM 5500;

[0052] Leveling agent: DSP-852, a fluorocarbon leveling agent from Jestar.

[0053] The preparation method includes the following steps:

[0054] (1) The raw materials of epoxy adhesive film layer (see Table 1) are evenly dispersed in a mixed solvent of N,N dimethylformamide (DMF) and butanone (MEK) (weight ratio 1:3) according to the weight ratio to obtain epoxy adhesive, and the solid content of the adhesive is controlled at 30%.

[0055] (2) Apply epoxy adhesive to the second release film (silicone release film), control the wet adhesive thickness to 20 μm, and dry and pre-cur at 100℃ for 3-6 min to obtain a black epoxy pure adhesive film coated on the heavy release film.

[0056] (3) Use a first light release film with antistatic properties for coating, and the coating temperature is 60-90℃ to obtain the encapsulation film for the MicroLED display module.

[0057] Table 1

[0058]

[0059] The films provided in Examples 1-4 and Comparative Examples 1-4 were subjected to relevant tests. The test methods for each test item are as follows:

[0060] Molding process: The adhesive film and substrate are vacuum-pressed at 110-120℃ with a pressure of 0.1Mpa-0.5Mpa (1-5 bar) for 100 seconds. Under specific temperature and pressure conditions, the adhesive film fills the entire mold cavity, encapsulating all the chips.

[0061] Curing reaction rate: The curing reaction rate of the adhesive film during molding and post-curing processes was tested using the DSC thermo-hang method. The test conditions were: temperature range of room temperature to 300℃, N2 atmosphere, and heating rate of 5℃ / min.

[0062] Initial tack: The initial tack of the adhesive surface is characterized by folding and contacting it. If there is no adhesion or indentation on the adhesive surface after unfolding, it means there is no initial tack; if there is slight indentation on the adhesive surface, it means low initial tack; if there is adhesion or damage on the adhesive surface, it means high initial tack.

[0063] Adhesion: By molding and pressing the adhesive film, followed by curing at 120℃ for 1 hour, and using a special cross-cut adhesion tester with a blade spacing of 1mm and an angle of 15°-30°, along with 3M 600 / 610 polyester film tape (adhesion strength 350-400g / cm²), adhesion is achieved. 2 The evaluation and testing were conducted according to GB / T 9286-1998. The results are divided into 6 levels according to the international standard: 5B level: no peeling, 4B level: peeling at intersections ≤5%, 3B level: peeling 5%-15%, 2B level: peeling 15%-35%, 1B level: peeling 35%-65%, and 0B level: peeling >65%.

[0064] Pencil hardness: The surface of the cured adhesive film is tested using a pencil hardness tester. The test is evaluated according to Clause 2.3 of the national standard GB 6739-86 "Coating Hardness - Pencil Hardness Method". The results are classified into 6H-6B, where a larger number before H indicates higher hardness, and a larger number before B indicates lower hardness. Therefore, 6H is the hardest grade of pencil hardness, and 6B is the softest grade.

[0065] Complex viscosity: The complex viscosity of the film at room temperature to 120°C was tested using a Thermo Scientific rheometer, and the lowest point of the test curve was taken as the complex viscosity value. Test conditions were: temperature: room temperature to 120°C, heating rate: 5°C / min.

[0066] Fill rate: The Micro-LED chip is vacuum-pressed through the molding process and then bonded and filled using a hot-pressing method. After bonding, it is placed in a 90℃ environment for 3-5 minutes, and the filling performance between the film and the chip is observed by using a cross-section sawing method and an optical microscope.

[0067] Peel voltage: The peel voltage between the first release film and the epoxy adhesive layer was measured by an electrometer. The sample size was A4 (210mm×297mm), and the average value of the peel range was taken as the peel voltage.

[0068] Warpage determination: Take a 330mm x 170mm long and 15μm thick adhesive film, remove the light release film, and then attach it to the Micro-LED panel using the molding process. The Micro-LED panel is 330mm long, 170mm wide, and 1mm thick. After the adhesive film is attached, place the Micro-LED panel in a 120℃ oven to cure for 1 hour, then remove it and place it on a flat table. Remove the heavy release film, press down one end of the Micro-LED panel, and measure the warpage height of one end of the Micro-LED panel using a ruler perpendicular to the table.

[0069] The test results are shown in Table 2.

[0070] Table 2

[0071] As shown in Table 2, the Micro LED encapsulation films provided in Examples 1-4 are made by combining different liquid epoxy and different toughening resins. The fluidity index-reviscosity of the films have certain differences. Their fluidity, chip filling performance, peel voltage and anti-warping performance are all excellent.

[0072] Compared with Example 1, no liquid epoxy was added in Comparative Example 1, resulting in a severe lack of fluidity in the prepared epoxy film, poor wettability of the film to the chip, and insufficient fluidity.

[0073] Compared with Example 1, the amount of nitrile rubber XER-32 added in Comparative Example 2 was too large, resulting in poor wetting of the epoxy film on the chip and insufficient filling.

[0074] Compared with Example 1, the amount of nano-silica added in Comparative Example 3 was too large, resulting in poor wetting of the epoxy film on the chip and insufficient filling.

[0075] Compared with Example 1, Comparative Example 4 had too much accelerator, which resulted in an excessively fast reaction process and excessive heat release in the epoxy film, leading to greater warping of the chip after curing.

[0076] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A micro LED display module encapsulation film, characterized in that, It includes a first release film layer, an epoxy adhesive film layer, and a second release film layer arranged in sequence; by weight, the epoxy adhesive film layer includes the following raw material components: 100 parts of solid epoxy resin, 5-20 parts of liquid epoxy resin, 5-20 parts of toughening resin, 10-30 parts of carbon black filler, 1-20 parts of silica, 1-10 parts of coupling agent, 2-10 parts of curing agent, 5-10 parts of accelerator, 0.1-2 parts of defoamer, and 0.05-0.5 parts of leveling agent.

2. The Micro LED display module encapsulation film as described in claim 1, characterized in that, The solid epoxy resin is selected from one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, hydrogenated bisphenol A epoxy resin, and aliphatic epoxy resin.

3. The Micro LED display module encapsulation film as described in claim 1, characterized in that, The liquid epoxy resin is selected from one or more of the following: bisphenol A epoxy resin, bisphenol F epoxy resin, aliphatic glycidyl ether epoxy resin, phenolic epoxy resin, hydrogenated bisphenol A epoxy resin, reactive diluent epoxy resin, and diluent epoxy resin.

4. The Micro LED display module encapsulation film as described in claim 1, characterized in that, The toughening resin is selected from one or more of the following: nitrile rubber and its carboxyl and epoxy modified compounds, phenoxy resin and its carboxyl and epoxy modified compounds, acrylate rubber and its carboxyl and epoxy modified compounds, and ethylene acrylate rubber and its carboxyl and epoxy modified compounds.

5. The Micro LED display module encapsulation film as described in claim 1, characterized in that, The curing agent is an anionic epoxy curing agent, selected from one or more of aliphatic amines, polyamides, aromatic amines, acid anhydrides, dicyandiamides, phenolic amines, thiols, and imidazoles.

6. The Micro LED display module encapsulation film as described in claim 1, characterized in that, The accelerator is selected from one or more of tertiary amines, imidazoles, organophosphorus compounds, transition metals, and phenols.

7. The Micro LED display module encapsulation film as described in claim 1, characterized in that, The first release film layer is a light release film, and the second release film layer is a heavy release film.

8. The Micro LED display module encapsulation film as described in claim 7, characterized in that, The second release film layer is selected from one of the following: silicone release film, non-silicone release film, and fluorine release film.

9. The encapsulating film for a Micro LED display module as described in claim 1, characterized in that, The leveling agent is a fluorocarbon type leveling agent.

10. The method for preparing the encapsulating film for a Micro LED display module as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Solid epoxy resin, liquid epoxy resin, toughening resin, carbon black filler, silica, coupling agent, curing agent, accelerator, defoamer, and leveling agent are dispersed in an organic solvent to obtain an epoxy adhesive. S2. The epoxy adhesive is applied to the second release film, dried and pre-cured to form an epoxy film layer. After being combined with the first release film, the Micro LED display module encapsulation film is obtained.

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