An epoxy resin composition and a film containing the same, an LED device

Abstract

The present application relates to an epoxy resin composition and a film and an LED device comprising the same, the epoxy resin composition comprising, by weight parts, the following components: epoxy resin 5-25 parts, toughening agent 2-5 parts, curing agent 8-20 parts, diffusing agent 1-5 parts; the epoxy resin comprises a combination of silicone epoxy resin, alicyclic epoxy resin and other epoxy resins; the content of the alicyclic epoxy resin is 25-50% of the total mass of the epoxy resin; the silicone epoxy resin is a silicone epoxy resin with a specific structure. The present application uses an epoxy resin composition with a specific composition to obtain a film with more excellent toughness and cold and hot impact performance, which can improve the product yield when applied to LED device packaging, avoid problems such as lamp plate deformation, dead lamp and interlayer cracking caused by warping during the packaging and curing process, improve process stability, and provide an effective solution for the large-scale commercial application of Mini LED.

Description

Technical Field

[0001] This invention relates to the field of encapsulating adhesives, and more particularly to an epoxy resin composition and an encapsulating film and LED device containing the same. Background Technology

[0002] With the continuous development of display technology, Mini LED, as a new type of display technology, has been widely used in the display field due to its advantages such as high brightness, high contrast, and high resolution. However, the packaging process of Mini LED remains one of the key factors restricting its large-scale production and application.

[0003] Molding is a traditional Mini LED packaging process that uses a mold and pressure and temperature to encapsulate and protect the exposed chip with epoxy resin, providing interconnection between the chip and other electronic components. Its main advantages include high-precision manufacturing, the ability to manufacture complex structures, simplified manufacturing processes, fast molding cycles, overflow-free and runner-free molding, and high-performance characteristics. For example, CN109251723A discloses a high-refractive-index LED encapsulating silicone for molding, comprising component A and component B, wherein the weight ratio of component A to component B is 3:1; wherein: component A comprises the following raw materials in parts by weight: 50-60 parts of methylphenyl vinyl silicone resin, 10-15 parts of vinyl silicone oil, 20-40 parts of hydrogen-containing small molecules, 5-10 parts of chain extender, and 0.5-1.0 parts of inhibitor; component B comprises the following raw materials in parts by weight: 75-85 parts of vinyl silicone oil, 10-20 parts of methylphenyl vinyl silicone resin, 5-10 parts of adhesive, and 0.5-1.5 parts of catalyst; the resulting high-refractive-index LED encapsulating silicone has the characteristics of high brightness, high refractive index, and is suitable for rapid curing in the fast stage of molding process. The preparation process is simple, easy to mass-produce, and suitable as LED encapsulating silicone.

[0004] However, traditional Mini LED packaging processes have many shortcomings. For example, traditional liquid adhesives have high curing shrinkage rates and high internal stress, leading to uneven packaging surfaces and chip misalignment, resulting in dead LEDs. Furthermore, the molding process involves complex mechanical operations and chemical treatments, making the entire packaging process time-consuming and severely impacting production efficiency. Secondly, due to the high precision requirements and the instability of material properties, it is difficult to effectively improve yield rates, increasing production costs. In addition, traditional packaging processes may cause damage to Mini LED devices during packaging, further reducing product quality. Currently, although there are some research reports on LED encapsulation films, these films exhibit warping after curing, poor process stability, and limited applicability, failing to meet the needs of Mini LED direct-view displays with different pixel pitches on the market.

[0005] Therefore, in order to address the above problems, a new Mini LED encapsulation film technology has been developed, which aims to simplify the encapsulation process, improve production efficiency, reduce production costs, and at the same time ensure encapsulation quality and yield. This has very important practical significance and application value. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides an epoxy resin composition and a film containing it, as well as an LED device. By compounding a specific epoxy resin composition with other components, the product yield is improved, and the stability of the production process is effectively controlled. Through further structural encapsulation processes, efficient and high-quality Mini LED encapsulation is achieved, solving the problems of long processing time, low yield, warping, instability, and poor practicality of existing encapsulation films in traditional Mini LED encapsulation processes. This provides an effective solution to the problems existing in traditional molding processes.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides an epoxy resin composition, which, by weight, comprises the following components: 5-25 parts epoxy resin, 2-5 parts toughening agent, 8-20 parts curing agent, and 1-5 parts dispersant.

[0009] The epoxy resin includes silicone epoxy resin, alicyclic epoxy resin and a combination of other epoxy resins;

[0010] The alicyclic epoxy resin content is 25-50% of the total mass of epoxy resin;

[0011] The organosilicon epoxy resin includes compounds having the structure shown in Formula I:

[0012]

[0013] Wherein, n1-n4 are each independently selected from 1-5 (e.g., they can be 1, 2, 3, 4 or 5), and R1-R4 are each independently selected from straight-chain or branched alkyl groups of C1-C5 (e.g., they can be C1, C2, C3, C4 or C5) and alkoxy groups of C1-C5 (e.g., they can be C1, C2, C3, C4 or C5).

[0014] The epoxy resin composition provided by this invention comprises a combination of at least three epoxy resins. The silicone epoxy resin has low surface tension and excellent wetting and dispersion effects with the dispersant. Furthermore, the silicone epoxy resin exhibits excellent heat resistance, and its addition solves the problem of poor dispersant agglomeration during the Mini LED display encapsulation process, improving product yield. On the other hand, a higher content of alicyclic epoxy resin during the pre-curing process results in a faster reaction rate. This invention effectively controls the stability of the production process by limiting the ratio of alicyclic to non-alicyclic epoxy resins. In addition, since alicyclic epoxy resins generally have a small molecular weight and poor toughness after curing, which is detrimental to film formation, controlling the ratio of alicyclic epoxy resins can effectively solve the problems of severe warping and film breakage in Mini LED displays. Simultaneously, the use of multifunctional silicone epoxy resins in this invention helps to improve its crosslinking degree with other components in the composition, further improving the toughness of the cured film and reducing warping or film breakage problems.

[0015] The epoxy resin is 5-25 parts by weight, for example, 6 parts, 7 parts, 8 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts or 24 parts, etc.

[0016] The toughening agent is 2-5 parts by weight, for example, 2.5 parts, 3 parts, 3.5 parts, 4 parts or 4.5 parts, etc.

[0017] The curing agent is 8-20 parts by weight, for example, 9 parts, 10 parts, 11 parts, 13 parts, 15 parts, 17 parts or 19 parts, etc.

[0018] The dispersant is 1-5 parts by weight, for example, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts or 4.5 parts, etc.

[0019] The alicyclic epoxy resin content is 25-50% of the total mass of epoxy resin, for example, it can be 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45% or 48%, etc.

[0020] Preferably, the content of the organosilicon epoxy resin is 8-20% of the total mass of the epoxy resin, for example, it can be 9%, 10%, 12%, 14%, 16% or 18%, etc.

[0021] Preferably, the organosilicon epoxy resin comprises a compound having a structure as shown in Formula II:

[0022]

[0023] Preferably, the relative molecular mass of the alicyclic epoxy resin is 200-500, for example, it can be 250, 300, 350, 400 or 450, etc.

[0024] Preferably, the other epoxy resins include aromatic epoxy resins.

[0025] Preferably, the aromatic epoxy resin includes bisphenol A epoxy resin and / or bisphenol F epoxy resin.

[0026] Preferably, the epoxy equivalent of the other epoxy resin is 100-200 g / eq, for example, it can be 110 g / eq, 130 g / eq, 150 g / eq, 170 g / eq or 190 g / eq, etc.

[0027] Preferably, the toughening agent comprises any one or a combination of at least two of acrylic rubber, core-shell styrene-butadiene rubber, nitrile rubber modified epoxy resin, polyurethane modified epoxy resin, or polyol, and more preferably a polyol.

[0028] Preferably, the polyol includes any one or a combination of at least two of ethylene glycol, propylene glycol, glycerol, dipropylene glycol, polypropylene glycol, polyester polyol or polyether polyol.

[0029] Preferably, the hydroxyl value of the polyol is 150-300 mgKOH / g, for example, it can be 160 mgKOH / g, 180 mgKOH / g, 200 mgKOH / g, 220 mgKOH / g, 240 mgKOH / g, 260 mgKOH / g or 280 mgKOH / g, etc.

[0030] As a preferred technical method of the present invention, a polyol toughening agent with a hydroxyl value of 150-300 mg KOH / g is used. Due to its excellent toughness and low glass transition temperature (Tg), it can improve the toughness of the film. At the same time, the Tg of the fully cured film is relatively small. When applied to Mini LED packaging, it can be completely removed by heating after curing, realizing rework. This solves the problem of difficult Mini LED rework in the prior art and further reduces costs.

[0031] Preferably, the curing agent includes anhydride-based curing agents.

[0032] Preferably, the anhydride curing agent includes any one or a combination of at least two of methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, or tetrahydrophthalic anhydride.

[0033] Preferably, the dispersant comprises any one or a combination of at least two of organosilicon microspheres, spherical silica, or spherical calcium carbonate.

[0034] Preferably, the particle size distribution D50 of the dispersant is 1-4 μm, for example, it can be 1.5 μm, 2 μm, 2.5 μm, 3 μm or 3.5 μm.

[0035] In this invention, the particle size distribution D50 refers to the particle size corresponding to the cumulative particle size distribution percentage of the sample reaching 50%, also known as the median particle size or median particle size.

[0036] Preferably, the refractive index of the diffusing agent is 1.4-1.5, for example, it can be 1.41, 1.43, 1.45, 1.47 or 1.49, etc.

[0037] Preferably, the amount of the dispersant is 5-10% of the total mass of the epoxy resin composition, for example, it can be 5.5%, 6%, 6.5%, 7%, 8% or 9%, etc.

[0038] Preferably, the epoxy resin composition further includes 0.1-0.3 parts by weight of coupling agent, such as 0.12 parts, 0.15 parts, 0.18 parts, 0.2 parts, 0.22 parts, 0.25 parts or 0.28 parts, etc.

[0039] Preferably, the coupling agent comprises a silane coupling agent.

[0040] Preferably, the silane coupling agent comprises any one or a combination of at least two of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, or 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0041] Preferably, the epoxy resin composition further includes 0.2-0.8 parts by weight of an accelerator, for example, 0.25 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts or 0.7 parts, etc.

[0042] Preferably, the accelerator comprises any one or a combination of at least two of tetramethylammonium bromide, tetrabutylammonium bromide, or triphenylphosphine.

[0043] Preferably, the epoxy resin composition further includes 0.02-0.08 parts by weight of a colorant, such as 0.03 parts, 0.04 parts, 0.05 parts, 0.06 parts, or 0.07 parts.

[0044] Preferably, the colorant includes a black colorant, such as black pigment powder or black pigment paste.

[0045] For example, nano-carbon black can be used as the colorant in this invention.

[0046] In this invention, the addition of a black colorant effectively solves the problem of difficult-to-cover substrate defects in traditional processes.

[0047] Preferably, the epoxy resin composition has a haze of ≥90%, for example, it can be 91%, 93%, 95%, 97% or 99%, etc.

[0048] Preferably, the opacity of the epoxy resin composition is ≥70%, for example, it can be 72%, 75%, 78%, 80%, 85%, 90% or 95%, etc.

[0049] Preferably, the epoxy resin composition has a refractive index ≥1.5, for example, it can be 1.55, 1.6, 1.7, 1.8, 1.9 or 2.0.

[0050] Preferably, the epoxy resin composition has a moisture content of <2%, for example, it can be 1.8%, 1.6%, 1.4%, 1.2%, 1%, 0.8%, 0.6%, 0.4%, 0.2%, 0.1%, or 0.05%, and more preferably <1%.

[0051] In a second aspect, the present invention provides a method for preparing the epoxy resin composition as described in the first aspect, the method comprising the following steps:

[0052] The epoxy resin, toughening agent, dispersant, and optionally coupling agent, optional accelerator, and optional colorant are mixed to obtain the epoxy resin composition.

[0053] Preferably, the preparation method includes the following steps:

[0054] (1) Mix epoxy resin, toughening agent and coupling agent to obtain a liquid mixture, then add dispersant and colorant and stir evenly to obtain epoxy resin matrix;

[0055] The curing agent and the accelerator are mixed to obtain the epoxy reactive component;

[0056] (2) The epoxy resin matrix obtained in step (1) is mixed with the epoxy reactive component to obtain the epoxy resin composition.

[0057] Preferably, the mixing time in step (1) is 20-30 min, for example, it can be 21 min, 23 min, 25 min, 27 min or 29 min.

[0058] Preferably, the time for stirring evenly in step (1) is 1-2 hours, for example, 1.1 hours, 1.3 hours, 1.5 hours, 1.7 hours or 1.9 hours.

[0059] Preferably, the mixing time in step (1) is 10-20 min, for example, it can be 11 min, 13 min, 15 min, 17 min or 19 min.

[0060] Preferably, the mixing in step (1) is carried out under vacuum.

[0061] Preferably, the mixing time in step (2) is 10-20 min, for example, 11 min, 13 min, 15 min, 17 min or 19 min.

[0062] Preferably, the mixing in step (2) is carried out under vacuum.

[0063] Thirdly, the present invention provides an adhesive film obtained by curing an epoxy resin composition as described in the first aspect.

[0064] Preferably, the adhesive film comprises a first release layer, a semi-cured adhesive film, and a second release layer stacked sequentially; wherein the raw materials for preparing the semi-cured adhesive film include the epoxy resin composition as described in the first aspect.

[0065] Preferably, the curing rate of the semi-cured adhesive film is 20-30%, for example, it can be 22%, 24%, 26% or 28%, etc.

[0066] Preferably, the release force of the first release layer is 1-15g / 25mm, for example, it can be 2g / 25mm, 4g / 25mm, 6g / 25mm, 8g / 25mm, 10g / 25mm, 12g / 25mm or 14g / 25mm, and more preferably 5-10g / 25mm.

[0067] Preferably, the release force of the second release layer is 15-35g / 25mm, for example, it can be 16g / 25mm, 18g / 25mm, 20g / 25mm, 22g / 25mm, 24g / 25mm, 26g / 25mm, 28g / 25mm, 30g / 25mm, 32g / 25mm or 34g / 25mm, etc., and more preferably 20-25g / 25mm.

[0068] As a preferred technical solution of the present invention, the use of a release layer with a specific release force has a positive effect on the appearance of the film material after tearing.

[0069] Fourthly, the present invention provides a method for preparing the adhesive film as described in the third aspect, the method comprising the following steps:

[0070] The epoxy resin composition as described in the first aspect is applied between the first release layer and the second release layer and cured to obtain the adhesive film.

[0071] Preferably, the coating speed is 0.1-0.5 m / min, for example, it can be 0.15 m / min, 0.2 m / min, 0.25 m / min, 0.3 m / min, 0.35 m / min, 0.4 m / min or 0.45 m / min, and more preferably 0.2-0.3 m / min.

[0072] Preferably, the curing includes pre-curing and cooling curing.

[0073] Preferably, the pre-curing temperature is 90-105℃, for example, it can be 92℃, 95℃, 98℃, 100℃ or 102℃, etc.

[0074] Preferably, the pre-curing time is 8-12 minutes, for example, it can be 8.5 minutes, 9 minutes, 9.5 minutes, 10 minutes, 10.5 minutes, 11 minutes or 11.5 minutes.

[0075] Preferably, the cooling and curing temperature is 85-100℃, for example, it can be 88℃, 90℃, 92℃, 95℃ or 98℃, etc.

[0076] Preferably, the cooling and curing time is 8-12 minutes, for example, it can be 8.5 minutes, 9 minutes, 9.5 minutes, 10 minutes, 10.5 minutes, 11 minutes or 11.5 minutes.

[0077] Fifthly, the present invention provides an encapsulation method, wherein the encapsulation method employs the adhesive film as described in the third aspect.

[0078] Preferably, the packaging method includes the following steps:

[0079] The adhesive film described in the third aspect is bonded to the panel to be encapsulated, and then heated to complete the encapsulation.

[0080] Preferably, the first release film is removed before bonding, and the exposed semi-cured adhesive film is bonded to the panel to be packaged.

[0081] Preferably, the bonding method includes roll bonding or hot pressing bonding.

[0082] Preferably, the bonding method is roll bonding, and the encapsulation method includes removing the first release film, preheating the adhesive film, and roll bonding it with the panel to be encapsulated.

[0083] Preferably, the preheating temperature is 70-90℃, for example, it can be 72℃, 75℃, 78℃, 80℃, 82℃, 85℃ or 88℃, etc.

[0084] Preferably, the preheating time is 10-15 minutes, for example, 10.5 minutes, 11 minutes, 12 minutes, 13 minutes or 14 minutes.

[0085] Preferably, the roll-pressing operation includes lifting one side of the adhesive film, aligning the other side of the semi-cured film layer with one side of the panel to be packaged, pressing the adhesive on top, applying pressure, and rolling it to the other side.

[0086] Preferably, the applied pressure is ≥0.6 kg / cm². 2 For example, it can be 0.65 kg / cm². 2 0.7kg / cm 2 0.8kg / cm 2 0.9kg / cm 2 1kg / cm 2 1.1kg / cm 2 1.2kg / cm 2 1.5kg / cm 2 1.8kg / cm 2 Or 2kg / cm 2 Further preferred values ​​are 0.8-1.2 kg / cm³. 2 .

[0087] Preferably, the speed of the roller pressing is ≤1m / min, for example, it can be 0.95m / min, 0.9m / min, 0.8m / min, 0.7m / min, 0.6m / min, 0.5m / min, 0.4m / min, 0.2m / min, 0.1m / min or 0.05m / min, and more preferably 0.4-0.8m / min.

[0088] Preferably, the temperature of the hot pressing is 40-80℃, for example, it can be 45℃, 50℃, 55℃, 60℃, 65℃, 70℃ or 75℃.

[0089] Preferably, the pressure of the hot pressing is 0.2-1 MPa, for example, it can be 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa or 0.8 MPa.

[0090] Preferably, the hot pressing time is 1-5 minutes, for example, 1.5 minutes, 2 minutes, 2.5 minutes, 3 minutes, 3.5 minutes, 4 minutes or 4.5 minutes.

[0091] Preferably, the heating temperature is 70-130℃, for example, it can be 75℃, 80℃, 90℃, 100℃, 110℃ or 120℃.

[0092] Preferably, the heating time is 0.5-3 hours, for example, 0.8 hours, 1 hour, 1.2 hours, 1.5 hours, 2 hours or 2.5 hours.

[0093] Preferably, the encapsulation method further includes removing the second release film.

[0094] In a sixth aspect, the present invention provides an LED device comprising an epoxy resin composition as described in the first aspect or an adhesive film as described in the third aspect.

[0095] Compared with the prior art, the present invention has at least the following beneficial effects:

[0096] The epoxy resin composition provided by this invention, through the compounding of a specific epoxy resin composition with other components, reduces encapsulation film warpage, improves product yield, and effectively controls production process stability. By further limiting the hydroxyl value of the polyol toughening agent, the resulting film can be repaired at lower temperatures, solving the pain point of difficult repair of liquid molding adhesives. Applying the epoxy composition provided by this invention to Mini LED encapsulation enables efficient and high-quality panel bonding, with short overall process time and low equipment investment, which is conducive to promoting the further development and application of Mini LED technology. Attached Figure Description

[0097] Figure 1 This is a schematic diagram of the adhesive film structure obtained in Example 1 of the present invention;

[0098] Figure 2 This is a schematic diagram illustrating the preparation of the adhesive film in Example 1 of the present invention;

[0099] in, Figure 1 1-First release layer, 2-Semi-cured adhesive film, 3-Second release layer;

[0100] Figure 2 1-First release layer, 12-Epoxy resin composition, 3-Second release layer, 4-First oven, 5-Second oven. Detailed Implementation

[0101] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0102] The specific grades of the substances used in the following examples are shown in Table 1.

[0103] Table 1

[0104]

[0105]

[0106] Example 1

[0107] An epoxy resin composition, by weight, comprises 5 parts of liquid bisphenol A type epoxy resin, 5 parts of bisphenol F type epoxy resin, 7 parts of alicyclic epoxy resin, 1.5 parts of organosilicon epoxy resin, 3 parts of toughening agent polyester polyol (AG-9006), 0.2 parts of silane coupling agent, 3.5 parts of dispersant organosilicon microspheres, 14.8 parts of acid anhydride curing agent, 0.5 parts of nitrogen-containing accelerator, and 0.07 parts of colorant;

[0108] The epoxy resin composition was prepared by the following method:

[0109] (1) Accurately weigh epoxy resin, toughening agent and coupling agent and place them in a new type of mixer and stir for 25 minutes to obtain a uniformly mixed liquid mixture. Then add accurately weighed dispersant and colorant to it and stir for 1 hour to make all materials uniformly mixed to obtain a black epoxy resin matrix.

[0110] Accurately weigh the curing agent and accelerator, stir them in another container under vacuum for 20 minutes to obtain a clear epoxy reaction component;

[0111] (2) The epoxy reaction component obtained in step (1) is mixed with the black epoxy resin matrix and stirred under vacuum for 20 minutes to obtain a viscous black glue, which is the epoxy resin composition.

[0112] Examples 2-5, Comparative Examples 1-3

[0113] An epoxy resin composition differs from Example 1 in that the formulation of the epoxy resin composition is different, as shown in Table 2; wherein, the amount of each component is expressed in "parts by weight" of solid content; the preparation method of the epoxy resin composition is the same as that of Example 1.

[0114] Table 2

[0115]

[0116] Comparative Example 4

[0117] Commercially available molding adhesive, Polomo EP2271, is a liquid encapsulating adhesive.

[0118] Application Example 1-5, Comparative Application Example 1-3

[0119] An adhesive film, the adhesive film structure as follows Figure 1 As shown, it includes a first release layer, a semi-cured film comprising the epoxy resin compositions obtained in Examples 1-5 and Comparative Examples 1-3, and a second release layer;

[0120] The preparation method of the adhesive film is as follows: Figure 2 As shown, it includes the following steps:

[0121] The epoxy resin compositions obtained in Examples 1-5 and Comparative Examples 1-3 were coated between the first release layer and the second release layer at a speed of 0.3 m / min, and then passed sequentially through a first oven and a second oven, both 4.5 m long. The temperature of the first oven was 100°C and the temperature of the second oven was 90°C, to obtain the adhesive film.

[0122] Comparative Application Example 4

[0123] Using the molding adhesive from Comparative Example 4, a Mini LED module was encapsulated using a traditional molding process. The bonding and lighting effects of the molding adhesive were tested.

[0124] The above-mentioned adhesive film was subjected to the following tests:

[0125] 1. Testing of the basic properties of the adhesive film

[0126] 1) Curing rate

[0127] The test was conducted according to the national standard GB / T 37498-2019. Samples from different batches of the same embodiment or comparative example were tested repeatedly 10 times, and the variance was calculated.

[0128] The above-mentioned adhesive film was cured at 130°C for 90 minutes, and then the film condition, glass transition temperature and tensile strength were tested.

[0129] 2) Film condition

[0130] Fold the film 180 degrees and observe its tearing.

[0131] 3) Glass transition temperature

[0132] Differential scanning calorimetry (DSC) was used for testing.

[0133] 4) Tensile strength

[0134] The elongation at break was tested according to the national standard GB / T 30776-2014.

[0135] The test results of the basic properties of the adhesive film are summarized in Table 3.

[0136] Table 3

[0137]

[0138]

[0139] Note: The experimental data in Table 3 are the physical properties of fully cured adhesive. The molding adhesive in Comparative Example 4 is a liquid adhesive, and the degree of curing is uncontrollable. It is different from the semi-cured adhesive film of this invention, so there is no curing rate test.

[0140] 2. Adhesive film bonding and lighting effect

[0141] After removing the first release layer of the adhesive film, the semi-cured adhesive film layer is hot-pressed onto the mini LED light board at a bonding pressure of 0.7 MPa and a bonding temperature of 80°C. Then, it is cured at 130°C for 2 hours. After complete curing, the second release layer is removed to obtain the Mini LED module, and the following tests are performed.

[0142] 1) Adhesive yield rate

[0143] Using the above method to encapsulate and bond 100 Mini LED modules, the percentage of modules that could be successfully lit and which did not show any visual defects such as diffusion powder agglomeration was counted.

[0144] 2) Repair capability

[0145] After the adhesive film is fully cured, heat the module to 130℃ for 10 minutes, peel off the adhesive film, and observe the adhesive film residue on the surface of the light board. If the adhesive film residue area on the light board surface is less than 10%, it is considered qualified.

[0146] 3) Warpage performance

[0147] After the Mini LED module is fully cured and the cutting process is completed, the display surface is laid flat on an absolutely flat plane, and the distance from the center of the lamp board to the plane is measured.

[0148] The test results for film bonding and lighting effects are summarized in Table 4.

[0149] Table 4

[0150]

[0151] The test results show that the epoxy resin composition and cured film provided by this invention, through the compounding of specific components, solve the problems of low yield, severe warpage, and dispersant agglomeration of traditional liquid molding adhesives. At the same time, it further improves its weather resistance and process stability, with a curing rate between 24-30%, and the variance of 10 repeated experiments is 0.3-0.41. In some preferred technical solutions, it provides a rework function that traditional molding adhesives cannot achieve, greatly reducing the manufacturing cost of MiniLEDs and facilitating the large-scale commercialization of MiniLEDs.

[0152] By comparing Examples 1 with Examples 4 and 5, it can be seen that the present invention, by using a polyol toughening agent and limiting its hydroxyl value range, can improve the toughness of the film. The Tg after complete curing is less than 90°C. When applied to Mini LED light board encapsulation and curing, it can be completely removed after heating at 130°C for 10 minutes, thus enabling rework.

[0153] By comparing Example 1 and Comparative Example 1, it can be seen that the present invention controls the ratio of alicyclic epoxy with a faster reaction rate to non-alicyclic epoxy with a slower reaction rate in the preparation of the film, thereby reducing warpage, improving product yield, and effectively controlling the stability of the production process.

[0154] Comparing Example 1 with Comparative Examples 2 and 3, it can be seen that the present invention, by using a low-surface-tension silicone epoxy resin, effectively promotes the dispersion of the diffusing agent, thus effectively avoiding the undesirable phenomenon of diffusing agent agglomeration during the encapsulation process. After the Mini LED module is lit, there are no undesirable phenomena such as diffusing powder agglomeration. Furthermore, the Mini LED module encapsulated with the film exhibits low warpage and low internal stress, effectively preventing problems such as lamp board deformation, dead LEDs, and interlayer cracking caused by warpage during the encapsulation and curing process.

[0155] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. An epoxy resin composition, characterized in that, The epoxy resin composition comprises, by weight, the following components: 5-25 parts epoxy resin, 2-5 parts toughening agent, 8-20 parts curing agent, and 1-5 parts dispersant. The epoxy resin includes silicone epoxy resin, alicyclic epoxy resin and a combination of other epoxy resins; The alicyclic epoxy resin content is 25-35% of the total mass of the epoxy resin; The organosilicon epoxy resin includes compounds having the structure shown in Formula I: Formula I; Wherein, n1-n4 are each independently selected from 1-5, and R1-R4 are each independently selected from C1-C5 straight-chain or branched alkyl groups and C1-C5 alkoxy groups; The other epoxy resins include aromatic epoxy resins; The aromatic epoxy resin includes bisphenol A epoxy resin and / or bisphenol F epoxy resin; The toughening agent includes any one or a combination of at least two of the following: acrylic rubber, core-shell styrene-butadiene rubber, nitrile rubber modified epoxy resin, polyurethane modified epoxy resin, or polyol.

2. The epoxy resin composition according to claim 1, characterized in that, The content of the organosilicon epoxy resin is 8-20% of the total mass of the epoxy resin.

3. The epoxy resin composition according to claim 1, characterized in that, The organosilicon epoxy resin includes compounds having the structure shown in Formula II: Formula II.

4. The epoxy resin composition according to claim 1, characterized in that, The relative molecular mass of the alicyclic epoxy resin is 200-500.

5. The epoxy resin composition according to claim 1, characterized in that, The epoxy equivalent of the other epoxy resins is 100-200 g / eq.

6. The epoxy resin composition according to claim 1, characterized in that, The toughening agent is a polyol.

7. The epoxy resin composition according to claim 6, characterized in that, The polyol includes any one or a combination of at least two of ethylene glycol, propylene glycol, glycerol, dipropylene glycol, polypropylene glycol, polyester polyol, or polyether polyol.

8. The epoxy resin composition according to claim 7, characterized in that, The hydroxyl value of the polyol is 150-300 mg KOH / g.

9. The epoxy resin composition according to claim 1, characterized in that, The curing agent includes anhydride-based curing agents.

10. The epoxy resin composition according to claim 9, characterized in that, The anhydride curing agent includes any one or a combination of at least two of methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, or tetrahydrophthalic anhydride.

11. The epoxy resin composition according to claim 1, characterized in that, The dispersant includes any one or a combination of at least two of organosilicon microspheres, spherical silica, or spherical calcium carbonate.

12. The epoxy resin composition according to claim 1, characterized in that, The particle size distribution D50 of the dispersant is 1-4 μm.

13. The epoxy resin composition according to claim 1, characterized in that, The refractive index of the diffuser is 1.4-1.

5.

14. The epoxy resin composition according to claim 1, characterized in that, The amount of the dispersant is 5-10% of the total mass of the epoxy resin composition.

15. The epoxy resin composition according to claim 1, characterized in that, The epoxy resin composition further includes 0.1-0.3 parts by weight of coupling agent.

16. The epoxy resin composition according to claim 15, characterized in that, The coupling agent includes a silane coupling agent.

17. The epoxy resin composition according to claim 16, characterized in that, The silane coupling agent includes any one or a combination of at least two of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, or 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

18. The epoxy resin composition according to claim 1, characterized in that, The epoxy resin composition further includes 0.2-0.8 parts by weight of an accelerator.

19. The epoxy resin composition according to claim 18, characterized in that, The accelerator includes any one or a combination of at least two of tetramethylammonium bromide, tetrabutylammonium bromide, or triphenylphosphine.

20. The epoxy resin composition according to claim 1, characterized in that, The epoxy resin composition further includes 0.02-0.08 parts by weight of colorant.

21. The epoxy resin composition according to claim 1, characterized in that, The epoxy resin composition has a haze of ≥90%.

22. The epoxy resin composition according to claim 1, characterized in that, The epoxy resin composition has a light-blocking rate of ≥70%.

23. The epoxy resin composition according to claim 1, characterized in that, The epoxy resin composition has a refractive index ≥1.

5.

24. The epoxy resin composition according to claim 1, characterized in that, The epoxy resin composition has a moisture content of <2%.

25. The epoxy resin composition according to claim 24, characterized in that, The epoxy resin composition has a moisture content of <1%.

26. A method for preparing the epoxy resin composition according to any one of claims 1-25, characterized in that, The preparation method includes the following steps: The epoxy resin, toughening agent, dispersant, and optionally coupling agent, optional accelerator, and optional colorant are mixed to obtain the epoxy resin composition.

27. The preparation method according to claim 26, characterized in that, The preparation method includes the following steps: (1) Mix epoxy resin, toughening agent and coupling agent to obtain a liquid mixture, then add dispersant and colorant and stir evenly to obtain epoxy resin matrix; The curing agent and the accelerator are mixed to obtain the epoxy reactive component; (2) The epoxy resin matrix obtained in step (1) is mixed with the epoxy reactive component to obtain the epoxy resin composition.

28. The preparation method according to claim 27, characterized in that, The mixing time in step (1) is 20-30 min.

29. The preparation method according to claim 27, characterized in that, The time for mixing evenly in step (1) is 1-2 h.

30. The preparation method according to claim 27, characterized in that, The mixing time in step (1) is 10-20 min.

31. The preparation method according to claim 27, characterized in that, The mixing described in step (1) is carried out under vacuum.

32. The preparation method according to claim 27, characterized in that, The mixing time in step (2) is 10-20 min.

33. The preparation method according to claim 27, characterized in that, The mixing described in step (2) is carried out under vacuum.

34. A film, characterized in that, The film is obtained by curing the epoxy resin composition as described in any one of claims 1-25.

35. A film, characterized in that, The adhesive film comprises a first release layer, a semi-cured adhesive film, and a second release layer stacked sequentially; wherein the raw materials for preparing the semi-cured adhesive film include the epoxy resin composition as described in any one of claims 1-25.

36. The adhesive film according to claim 35, characterized in that, The release force of the first release layer is 1-15 g / 25mm.

37. The adhesive film according to claim 36, characterized in that, The release force of the first release layer is 5-10 g / 25mm.

38. The adhesive film according to claim 35, characterized in that, The release force of the second release layer is 15-35 g / 25mm.

39. The adhesive film according to claim 38, characterized in that, The release force of the second release layer is 20-25 g / 25mm.

40. A method for preparing the adhesive film according to any one of claims 35-39, characterized in that, The preparation method includes the following steps: The epoxy resin composition as described in any one of claims 1-25 is applied between the first release layer and the second release layer and cured to obtain the adhesive film.

41. The preparation method according to claim 40, characterized in that, The coating speed is 0.1-0.5 m / min.

42. The preparation method according to claim 41, characterized in that, The coating speed is 0.2-0.3 m / min.

43. The preparation method according to claim 40, characterized in that, The curing process includes pre-curing and cooling curing.

44. The preparation method according to claim 43, characterized in that, The pre-curing temperature is 90-105℃.

45. The preparation method according to claim 43, characterized in that, The pre-curing time is 8-12 minutes.

46. ​​The preparation method according to claim 43, characterized in that, The temperature for cooling and curing is 85-100℃.

47. The preparation method according to claim 43, characterized in that, The cooling and curing time is 8-12 minutes.

48. A packaging method, characterized in that, The encapsulation method uses the adhesive film as described in any one of claims 34-39.

49. The packaging method according to claim 48, characterized in that, The encapsulation method includes the following steps: The adhesive film as described in any one of claims 34-39 is bonded to the panel to be encapsulated, and then heated to complete the encapsulation.

50. The packaging method according to claim 49, characterized in that, Before bonding, the first release film is removed, and the exposed semi-cured adhesive film is bonded to the panel to be packaged.

51. The packaging method according to claim 49, characterized in that, The bonding method includes roll bonding or hot pressing bonding.

52. The packaging method according to claim 51, characterized in that, The bonding method is roll bonding, and the encapsulation method includes removing the first release film, preheating the adhesive film, and roll bonding it with the panel to be encapsulated.

53. The packaging method according to claim 52, characterized in that, The preheating temperature is 70-90℃.

54. The packaging method according to claim 52, characterized in that, The preheating time is 10-15 minutes.

55. The packaging method according to claim 52, characterized in that, The roll-pressing operation includes lifting one side of the adhesive film, aligning the other side of the semi-cured film layer with one side of the panel to be packaged, pressing the adhesive on top, applying pressure, and rolling it to the other side.

56. The packaging method according to claim 55, characterized in that, The applied pressure is ≥0.6 kg / cm². 2 .

57. The packaging method according to claim 56, characterized in that, The applied pressure is 0.8-1.2 kg / cm². 2 .

58. The packaging method according to claim 55, characterized in that, The speed of the roller pressing is ≤1 m / min.

59. The packaging method according to claim 58, characterized in that, The speed of the roller pressing is 0.4-0.8 m / min.

60. The packaging method according to claim 51, characterized in that, The temperature for hot pressing is 40-80℃.

61. The packaging method according to claim 51, characterized in that, The pressure for hot pressing is 0.2-1 MPa.

62. The packaging method according to claim 51, characterized in that, The hot-pressing bonding time is 1-5 minutes.

63. The packaging method according to claim 49, characterized in that, The heating temperature is 70-130℃.

64. The packaging method according to claim 49, characterized in that, The heating time is 0.5-3 hours.

65. The packaging method according to claim 50, characterized in that, The encapsulation method further includes removing the second release film.

66. An LED device, characterized in that, The LED device includes the epoxy resin composition as described in any one of claims 1-25 or the adhesive film as described in any one of claims 34-39.

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