Epoxy resin composition, preparation method and application thereof, LED display screen, packaging method thereof and electronic product

Abstract

The present invention relates to an epoxy resin composition, its preparation method and application, an LED display screen, its packaging method, and an electronic product. The epoxy resin composition comprises, by weight, 10 to 60 parts of an aliphatic epoxy resin, 10 to 30 parts of a hydantoin epoxy resin, 5 to 10 parts of amino-modified silica, and 10 to 50 parts of an anhydride curing agent. By properly proportioning the aliphatic epoxy resin, hydantoin epoxy resin, amino-modified silica, and anhydride curing agent, the epoxy resin composition, upon curing, can form an encapsulation layer structure with excellent light uniformity, water resistance, and long-term stability.

Description

Technical Field

[0001] The present invention relates to the technical field of LED device packaging, and in particular to an epoxy resin composition, a preparation method and application thereof, an LED display screen, a packaging method thereof, and an electronic product. Background Art

[0002] LED display is a new type of information display media. It is a flat display screen composed of light-emitting diode dot matrix modules or pixel units. It is widely used because of its advantages such as bright colors, wide dynamic range, high brightness, long life, stable and reliable operation.

[0003] LED displays manufactured using the COB (chip-on-board) packaging process offer advantages over traditional SMT (Surface Mount Technology) packaging processes, such as higher packaging efficiency and better visual quality. Traditional COB packaging uses epoxy resin as the packaging material, but epoxy resin has issues such as a low refractive index, high water absorption, and poor long-term stability. Summary of the Invention

[0004] Based on this, the present invention provides an epoxy resin composition, a preparation method and an application thereof. After curing, the epoxy resin composition has better light uniformity, water resistance and long-term stability, and is suitable for the packaging of LED display screens.

[0005] One aspect of the present invention provides an epoxy resin composition, which comprises, by weight:

[0006]

[0007]

[0008] In some embodiments, the alicyclic epoxy resin includes at least one of diglycidyl cyclohexane-1,2-dicarboxylate, diglycidyl 4,5-epoxycyclohexane-1,2-dicarboxylate, and 4-vinyl-1-cyclohexene diepoxide.

[0009] In some embodiments, the hydantoin epoxy resin includes at least one of 5-methyl-5-ethylhydantoin epoxy resin, 5-phenylhydantoin epoxy resin, and 5,5-dimethylhydantoin epoxy resin.

[0010] In some embodiments, the method for preparing the amino-modified silica comprises:

[0011] Mix the amino modifier, solvent and silica microspheres and react at 45°C to 60°C for 3h to 5h.

[0012] In some embodiments, the amino modifier includes at least one of ethylenediamine, diethylenetriamine, triethylenetetramine and boron amine compounds.

[0013] In some embodiments, the anhydride curing agent includes at least one of methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride and methylhexahydrophthalic anhydride.

[0014] In some embodiments, the epoxy resin composition further comprises at least one of a curing accelerator and an antioxidant; and the epoxy resin composition satisfies at least one of the conditions (1) to (4):

[0015] (1) The mass fraction of the curing accelerator is 0.1 to 1 part;

[0016] (2) the curing accelerator comprises at least one of ethyl levulinate and triethylenetetramine;

[0017] (3) The weight percentage of the antioxidant is 0.05 to 1 part;

[0018] (4) The antioxidant includes at least one of antioxidant 1010, antioxidant 1076 and antioxidant 168.

[0019] Another aspect of the present invention further provides a method for preparing the above-mentioned epoxy resin composition, comprising the following steps:

[0020] Mixing a cycloaliphatic epoxy resin and a hydantoin epoxy resin to prepare a first mixture;

[0021] Mixing an anhydride curing agent and amino-modified silica to prepare a second mixture;

[0022] The first mixture and the second mixture are mixed to prepare the epoxy resin composition.

[0023] Another aspect of the present invention provides use of the epoxy resin composition in preparing an LED display screen.

[0024] Another aspect of the present invention provides a method for packaging an LED display screen, comprising the following steps:

[0025] Covering the surface of the LED display module with the epoxy resin composition described above to prepare an encapsulation layer;

[0026] The encapsulation layer is cured.

[0027] In some embodiments, after the step of curing the encapsulation layer, the method further includes:

[0028] performing vacuum plasma treatment on the surface of the cured encapsulation layer;

[0029] A black matte coating is prepared on the surface of the packaging layer that has been subjected to vacuum plasma treatment.

[0030] In some embodiments, the curing process includes a first curing process and a second curing process; the curing process satisfies at least one of the conditions (1) to (4):

[0031] (1) The temperature of the first curing treatment is 70°C to 90°C;

[0032] (2) The first curing treatment time is 0.5h to 1h;

[0033] (3) The temperature of the second curing treatment is 110° C. to 140° C.;

[0034] (4) The second curing treatment time is 1 hour to 2 hours.

[0035] Another aspect of the present invention provides an LED display screen, the packaging structure of which includes a packaging layer made from the above-mentioned epoxy resin composition.

[0036] Another aspect of the present invention provides an electronic product including the above-mentioned LED display screen.

[0037] The epoxy resin composition is prepared by rationally mixing alicyclic epoxy resin, hydantoin epoxy resin, amino-modified silica and anhydride curing agent, and can form an encapsulation layer structure with good light uniformity, water resistance and long-term stability after curing.

[0038] The LED display screen obtained by encapsulating the epoxy resin composition has the characteristics of uniform light output, high stability, resistance to ultraviolet aging, low water absorption and high long-term reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic structural diagram of an LED display screen according to one embodiment of the present invention;

[0040] Description of reference numerals:

[0041] 10. LED display screen; 100. LED display module; 110. Circuit board; 120. LED chip; 200. Encapsulation layer; 300. Black matte coating. DETAILED DESCRIPTION

[0042] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the accompanying drawings. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0044] One embodiment of the present invention provides an epoxy resin composition, which comprises, by weight:

[0045]

[0046] The epoxy resin composition is prepared by rationally mixing alicyclic epoxy resin, hydantoin epoxy resin, amino-modified silica and anhydride curing agent, and can form an encapsulation layer structure with good light uniformity, water resistance and long-term stability after curing.

[0047] Alicyclic epoxy resin has the advantages of certain strength and low price, and is the main packaging material used in LED display COB packaging. In an embodiment of the present invention, the mass fraction of the cycloaliphatic epoxy resin in the epoxy resin composition is 10 parts to 60 parts. Optionally, the mass fraction of the cycloaliphatic epoxy resin in the epoxy resin composition is 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts or 60 parts. Furthermore, the mass fraction of the cycloaliphatic epoxy resin in the epoxy resin composition is 40 parts to 50 parts.

[0048] In some embodiments, the cycloaliphatic epoxy resin includes at least one of diglycidyl cyclohexane-1,2-dicarboxylate, diglycidyl 4,5-epoxycyclohexane-1,2-dicarboxylate, and 4-vinyl-1-cyclohexene diepoxide.

[0049] Hydantoin epoxy resin can improve the thermal stability, UV aging resistance, water resistance, and long-term reliability of epoxy resin compositions. In an embodiment of the present invention, the amount of hydantoin epoxy resin in the epoxy resin composition is 10 to 30 parts by weight. Alternatively, the amount of hydantoin epoxy resin in the epoxy resin composition is 10, 15, 20, 25, or 30 parts by weight.

[0050] In some embodiments, the hydantoin epoxy resin includes at least one of 5-methyl-5-ethylhydantoin epoxy resin, 5-phenylhydantoin epoxy resin, and 5,5-dimethylhydantoin epoxy resin.

[0051] Amino-modified silica is modified with amino groups and has good dispersibility and compatibility in epoxy resin compositions. The addition of amino-modified silica can improve the refractive index and light uniformity of the encapsulation resin prepared from the epoxy resin composition. In addition, amino-modified silica can play a long-term curing role and improve the strength of the epoxy resin composition after curing. In an embodiment of the present invention, the mass fraction of amino-modified silica in the epoxy resin composition is 5 to 10 parts. Optionally, the mass fraction of amino-modified silica in the epoxy resin composition is 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts.

[0052] In some embodiments, amino-modified silica is prepared by a method comprising the following steps: mixing an amino modifier, a solvent, and silica microspheres, and reacting the mixture at 45° C. to 60° C. for 3 h to 5 h.

[0053] Specifically, the preparation method of amino-modified silica may include: stirring an amino modifier and a solvent at 45°C to 60°C for 0.5 to 1 hour, then adding silica microspheres, and reacting at 45°C to 60°C for 3 to 5 hours. Then, centrifuging and separating the precipitate, and drying to obtain amino-modified silica.

[0054] In some embodiments, the amino modifier includes at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, and boron amine compounds.

[0055] In some embodiments, the solvent is a mixture of ethanol and water in a mass ratio of (0.8-1.2): 1. Furthermore, the mass ratio of ethanol to water is 1:1.

[0056] In some embodiments, the mass ratio of the amino modifier, the solvent, and the silica microspheres is (5-10):(80-90):(5-10).

[0057] The anhydride curing agent can crosslink and cure the alicyclic epoxy resin and hydantoin epoxy resin in the epoxy resin composition at high temperature. In an embodiment of the present invention, the mass fraction of the anhydride curing agent in the epoxy resin composition is 10 to 50 parts. Optionally, the mass fraction of the anhydride curing agent in the epoxy resin composition is 10, 15, 20, 25, 30, 35, 40, 45 or 50 parts. Furthermore, the mass fraction of the anhydride curing agent in the epoxy resin composition is 40 to 50 parts.

[0058] In some embodiments, the anhydride curing agent includes at least one of methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride. The anhydride curing agent can reduce internal stress and bubbles in the epoxy resin composition, thereby improving the performance of the cured epoxy resin.

[0059] In some embodiments, the epoxy resin composition further comprises at least one of a curing accelerator and an antioxidant.

[0060] The function of the curing accelerator is to accelerate the gel curing process and improve the curing efficiency of the epoxy resin composition. In some embodiments, the mass fraction of the curing accelerator is 0.1 to 1 parts. Alternatively, the mass fraction of the curing accelerator is 0.1 parts, 0.2 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.8 parts, 0.9 parts or 1 parts. In some embodiments, the curing accelerator includes at least one of ethyl levulinate and triethylenetetramine.

[0061] In some embodiments, the curing accelerator includes ethyl levulinate and triethylenetetramine, and the mass ratio of ethyl levulinate to triethylenetetramine is (1.5-2.5):1, for example, 2:1.

[0062] The function of the antioxidant is to inhibit oxidative aging of the epoxy resin composition, thereby improving the long-term reliability of the epoxy resin composition. In some embodiments, the weight fraction of the antioxidant is 0.05 to 1 part. Optionally, the weight fraction of the antioxidant is 0.05, 0.1, 0.2, 0.4, 0.5, 0.6, 0.8, or 1 part. The antioxidant includes at least one of antioxidant 1010, antioxidant 1076, and antioxidant 168. In some embodiments, the antioxidant includes a long-acting antioxidant and a short-acting antioxidant in a mass ratio of 1: (1.8 to 2.2). Furthermore, the mass ratio of the long-acting antioxidant to the short-acting antioxidant is 1:2. Among them, antioxidant 1010 and antioxidant 1076 are long-acting antioxidants, and antioxidant 168 is a short-acting antioxidant. The combination of long-acting antioxidants and short-acting antioxidants can further improve the long-term reliability of the epoxy resin composition.

[0063] In some embodiments, in the epoxy resin composition, the ratio of the mass of the alicyclic epoxy resin and the hydantoin epoxy resin to the mass of the anhydride curing agent is 1:(0.5-1.2), and further is 1:(0.8-1.2).

[0064] In some embodiments, in the epoxy resin composition, the total amount of the alicyclic epoxy resin, hydantoin epoxy resin and anhydride curing agent is 100 to 120 parts by mass, for example, 100 parts, 105 parts, 110 parts, 115 parts, and 120 parts.

[0065] Another embodiment of the present invention further provides a method for preparing the epoxy resin composition, comprising the following steps S110 to S130.

[0066] Step S110: Mixing the alicyclic epoxy resin and the hydantoin epoxy resin to prepare a first mixture.

[0067] Specifically, a planetary vacuum mixer may be used to stir and mix the alicyclic epoxy resin and the hydantoin epoxy resin for 10 to 15 minutes to obtain the first mixture.

[0068] Step S120: Mixing an anhydride curing agent and amino-modified silica to prepare a second mixture.

[0069] Specifically, a planetary vacuum mixer is used to stir and mix the acid anhydride curing agent and the amino-modified silica for 10 minutes to 15 minutes to obtain a second mixture.

[0070] In some embodiments, the second mixture further comprises a curing accelerator and an antioxidant. Specifically, the curing accelerator, the antioxidant, the anhydride curing agent and the amino-modified silica can be stirred and mixed.

[0071] Step S130: Mix the first mixture and the second mixture to prepare an epoxy resin composition.

[0072] In some embodiments, a planetary vacuum mixer is used to stir and mix the first mixture and the second mixture for 10 to 15 minutes to obtain the epoxy resin composition.

[0073] Another embodiment of the present invention further provides the use of the above-mentioned epoxy resin composition in the preparation of an LED display screen.

[0074] After curing, the above-mentioned epoxy resin combination can form a packaging layer structure with good light uniformity, water resistance and long-term stability. By using the above-mentioned epoxy resin composition to encapsulate and prepare an LED display screen, an LED display screen with uniform light output, high stability, resistance to UV aging, low water absorption and high long-term reliability can be obtained.

[0075] Another embodiment of the present invention further provides a method for packaging an LED display screen, including the following steps S210 to S220.

[0076] Step S210: Covering the surface of the LED display module with the epoxy resin composition to prepare an encapsulation layer.

[0077] In some embodiments, in step S210 , the surface of the LED display module is covered with an epoxy resin composition through a molding packaging process.

[0078] In some embodiments, the temperature of the compression molding process is 120° C. to 150° C., and the compression molding time is 150 seconds to 300 seconds. Through the compression molding process, the epoxy resin composition is initially formed to obtain an encapsulation layer.

[0079] In some embodiments, the thickness of the encapsulation layer is 0.2 mm to 0.5 mm. Optionally, the thickness of the encapsulation layer is 0.2 mm, 0.3 mm, 0.4 mm or 0.5 mm.

[0080] In some embodiments, before step S210, the method further includes:

[0081] Step S200: vacuum plasma treatment is performed on the surface of the LED display module. Vacuum plasma treatment of the surface of the LED display module can improve the adhesion of the surface of the LED display module and enhance the bonding force between the LED display module and the packaging layer.

[0082] In some embodiments, in step S200 , the RF power of the vacuum plasma treatment is 100 W to 200 W; and the time of the vacuum plasma treatment is 20 s to 100 s.

[0083] Step S220: performing a curing process on the encapsulation layer. By performing a curing process on the encapsulation layer, the long-term curing strength of the encapsulation layer can be further improved.

[0084] In some embodiments, the curing process includes a first curing process and a second curing process.

[0085] In some embodiments, the temperature of the first curing treatment is 70° C. to 90° C.; and the time of the first curing treatment is 0.5 h to 1 h.

[0086] In some embodiments, the temperature of the second curing treatment is 110° C. to 140° C.; and the time of the second curing treatment is 1 hour to 2 hours.

[0087] In some embodiments, after step S220, the method further includes:

[0088] Step S230: performing vacuum plasma treatment on the surface of the cured encapsulation layer. Performing vacuum plasma treatment on the surface of the encapsulation layer can improve its surface adhesion, facilitating the subsequent preparation of a functional coating.

[0089] In some embodiments, in step S230 , the RF frequency of the vacuum plasma treatment is 100W to 200W; and the duration of the vacuum plasma treatment is 20s to 100s.

[0090] In some embodiments, after step S230, the method further includes:

[0091] Step S240: preparing a black matte coating on the surface of the encapsulation layer that has been subjected to vacuum plasma treatment. By preparing the black matte coating on the surface of the encapsulation layer, the light output of the LED display screen can be made more uniform and the ink color consistency can be improved.

[0092] In some embodiments, the black matte coating is prepared by spraying black matte paint on the surface of the encapsulation layer through an inkjet process.

[0093] In some embodiments, the thickness of the black matte coating is 10 μm to 30 μm. Optionally, the thickness of the black matte coating is 10 μm, 15 μm, 20 μm, 25 μm or 30 μm.

[0094] The LED display screen prepared according to the above packaging method has good light uniformity, UV aging resistance, water resistance and long-term reliability, and the overall performance of the LED display screen is good.

[0095] Another embodiment of the present invention provides an LED display screen, the packaging structure of which includes a packaging layer made from the above-mentioned epoxy resin composition.

[0096] See Figure 1 In some embodiments, the LED display screen 10 includes an LED display module 100 , an encapsulation layer 200 and a black matte coating 300 .

[0097] The LED display module 100 includes a circuit board 110 and an LED chip 120 . The LED chip 120 is disposed on a surface of the circuit board 110 .

[0098] The encapsulation layer 200 is disposed on the surface of the LED display module 100 and covers the LED chip 120. The encapsulation layer 200 is prepared from the above-mentioned epoxy resin composition.

[0099] The black matte coating 300 is disposed on a surface of the encapsulation layer 200 away from the LED display module 100 .

[0100] Another embodiment of the present invention provides an electronic product including the above-mentioned LED display screen. Specific embodiments

[0102] The following is a detailed description of the invention with reference to specific examples. The following examples do not include any other components except for unavoidable impurities unless otherwise specified. The reagents and instruments used in the examples are conventionally selected in the art unless otherwise specified. The experimental methods for which specific conditions are not specified in the examples are carried out according to conventional conditions, such as those described in the literature, books, or methods recommended by the manufacturer. In the following examples and comparative examples, unless otherwise specified, parts are by mass.

[0103] Example 1

[0104] This embodiment provides an epoxy resin composition and an LED display screen encapsulated by the epoxy resin composition.

[0105] The epoxy resin composition of this embodiment includes, by weight, 50 parts of an alicyclic epoxy resin (4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester), 10 parts of a hydantoin epoxy resin (5-methyl-5-ethylhydantoin epoxy resin), 50 parts of an anhydride curing agent (methyltetrahydrophthalic anhydride), 5 parts of amino-modified silica, 0.3 parts of a curing accelerator, and 0.1 parts of an antioxidant. The curing accelerator is ethyl levulinate and triethylenetetramine in a 2:1 mass ratio. The antioxidant is antioxidant 1010 and antioxidant 168 in a 1:2 mass ratio.

[0106] The preparation of amino-modified silica involves adding 80 parts of a solvent (a mixture of ethanol and water in a 1:1 mass ratio) and 5 parts of an amino modifier (ethylenediamine) to a reaction kettle, stirring at 50°C for 0.5 hours, then slowly adding 5 parts of silica microspheres (particle size 2-10 microns), and continuing to stir at 50°C for 4 hours. After the reaction is completed, the precipitate is separated using a centrifuge, and the solvent in the precipitate is dried in an oven to obtain amino-modified silica.

[0107] The epoxy resin composition is prepared by mixing an alicyclic epoxy resin and a hydantoin epoxy resin using a planetary mixer for 10 minutes to obtain a first mixture. An anhydride curing agent, amino-modified silica, an antioxidant, and a curing accelerator are mixed using a planetary mixer for 10 minutes to obtain a second mixture. The first and second mixtures are mixed using a planetary mixer for 10 minutes to obtain the epoxy resin composition.

[0108] The preparation method of the LED display screen includes:

[0109] (1) The surface of the LED display module is subjected to vacuum plasma treatment with a radio frequency power of 100 W and a time of 20 s.

[0110] (2) Covering the surface of the LED display module obtained in step (1) with the epoxy resin composition through a compression molding process. The temperature of the compression molding process is 120° C. and the time is 300 s. The epoxy resin composition is initially formed to obtain a packaging layer with a thickness of 0.2 mm.

[0111] (3) The encapsulation layer is subjected to two stages of curing treatment in sequence: the first stage of curing treatment is at a temperature of 70°C for 1 hour, and the second stage of curing treatment is at a temperature of 120°C for 2 hours.

[0112] (4) The surface of the encapsulation layer obtained in step (3) was subjected to vacuum plasma treatment at a radio frequency power of 100 W for 50 seconds. Then, a black matte coating was sprayed on the surface of the encapsulation layer using an inkjet process to form a black matte coating with a thickness of 15 μm.

[0113] The packaged LED display screen of this embodiment has good long-term reliability and light uniformity. After being placed outdoors for 30 days, no yellowing, color cast, or screen defects occur, and the light transmittance reaches 90%.

[0114] Example 2

[0115] This embodiment provides an epoxy resin composition and an LED display screen encapsulated by the epoxy resin composition.

[0116] The epoxy resin composition of this embodiment includes, by weight, 40 parts of an alicyclic epoxy resin (cyclohexane-1,2-dicarboxylic acid diglycidyl ester), 20 parts of a hydantoin epoxy resin (5-phenylhydantoin epoxy resin), 40 parts of an anhydride curing agent (methyltetrahydrophthalic anhydride and hexahydrophthalic anhydride in a 1:1 mass ratio), 8 parts of amino-modified silica, 0.6 parts of a curing accelerator, and 0.4 parts of an antioxidant. The curing accelerator is ethyl levulinate and triethylenetetramine in a 2:1 mass ratio. The antioxidant is Antioxidant 1076 and Antioxidant 168 in a 1:2 mass ratio.

[0117] The preparation of amino-modified silica involves adding 90 parts of a solvent (a mixture of ethanol and water in a 1:1 mass ratio) and 5 parts of an amino modifier (boramine) to a reaction kettle, stirring at 50°C for 0.5 hours, then slowly adding 5 parts of silica microspheres (particle size 2-10 microns), and continuing stirring at 50°C for 4 hours. After the reaction is completed, the precipitate is separated using a centrifuge, and the solvent in the precipitate is dried in an oven to obtain amino-modified silica.

[0118] The epoxy resin composition is prepared by mixing an alicyclic epoxy resin and a hydantoin epoxy resin using a planetary mixer for 10 minutes to obtain a first mixture. An anhydride curing agent, amino-modified silica, an antioxidant, and a curing accelerator are mixed using a planetary mixer for 10 minutes to obtain a second mixture. The first and second mixtures are mixed using a planetary mixer for 10 minutes to obtain the epoxy resin composition.

[0119] The preparation method of the LED display screen includes:

[0120] (1) The surface of the LED display module is subjected to vacuum plasma treatment with a radio frequency power of 100 W and a time of 20 s.

[0121] (2) Covering the surface of the LED display module obtained in step (1) with the epoxy resin composition through a compression molding process. The temperature of the compression molding process is 130° C. and the time is 220 s. The epoxy resin composition is initially formed to obtain a packaging layer with a thickness of 0.3 mm.

[0122] (3) The encapsulation layer is subjected to two-stage curing treatment in sequence: the first stage curing treatment temperature is 90°C and the time is 0.5h, and the second stage curing treatment temperature is 140°C and the time is 1h.

[0123] (4) The surface of the encapsulation layer obtained in step (3) was subjected to vacuum plasma treatment at a radio frequency power of 200 W for 20 seconds. Then, a black matte coating was sprayed on the surface of the encapsulation layer using an inkjet process to form a black matte coating with a thickness of 20 μm.

[0124] The LED display screen packaged in this embodiment has good long-term reliability and light uniformity. After being placed outdoors for 30 days, no yellowing, color cast, or screen defects occur, and the light transmittance reaches 88.9%.

[0125] Example 3

[0126] This embodiment provides an epoxy resin composition and an LED display screen encapsulated by the epoxy resin composition.

[0127] The epoxy resin composition of this embodiment includes, by weight, 40 parts of an alicyclic epoxy resin (4-vinyl-1-cyclohexene diepoxide), 30 parts of a hydantoin epoxy resin (5,5-dimethylhydantoin epoxy resin), 40 parts of an anhydride curing agent (hexahydrophthalic anhydride and methylhexahydrophthalic anhydride in a 1:1 mass ratio), 10 parts of amino-modified silica, 0.3 parts of a curing accelerator, and 1 part of an antioxidant. The curing accelerator is ethyl levulinate and triethylenetetramine in a 2:1 mass ratio. The antioxidant is Antioxidant 1010 and Antioxidant 168 in a 1:2 mass ratio.

[0128] The preparation of amino-modified silica involves adding 90 parts of a solvent (a mixture of ethanol and water in a 1:1 mass ratio) and 5 parts of an amino modifier (a mixture of triethylenetetramine and boron amine in a 1:4 mass ratio) to a reaction kettle, stirring at 50°C for 0.5 hours, then slowly adding 5 parts of silica microspheres (particle size 2-10 microns), and continuing stirring at 50°C for 4 hours. After the reaction is completed, the precipitate is separated using a centrifuge, and the solvent in the precipitate is dried in an oven to obtain amino-modified silica.

[0129] The epoxy resin composition is prepared by mixing an alicyclic epoxy resin and a hydantoin epoxy resin using a planetary mixer for 10 minutes to obtain a first mixture. An anhydride curing agent, amino-modified silica, an antioxidant, and a curing accelerator are mixed using a planetary mixer for 10 minutes to obtain a second mixture. The first and second mixtures are mixed using a planetary mixer for 10 minutes to obtain the epoxy resin composition.

[0130] The preparation method of the LED display screen includes:

[0131] (1) The surface of the LED display module is subjected to vacuum plasma treatment with a radio frequency power of 200 W and a time of 20 seconds.

[0132] (2) Covering the surface of the LED display module obtained in step (1) with the epoxy resin composition through a compression molding process. The temperature of the compression molding process is 140° C. and the time is 180 s. The epoxy resin composition is initially formed to obtain a packaging layer with a thickness of 0.25 mm.

[0133] (3) Curing treatment of the encapsulation layer: the first curing treatment temperature is 80° C. and the time is 1 hour, and the second curing treatment temperature is 130° C. and the time is 1.5 hours.

[0134] (4) The surface of the encapsulation layer obtained in step (3) was subjected to vacuum plasma treatment at a radio frequency power of 200 W for 50 seconds. Then, a black matte coating was sprayed on the surface of the encapsulation layer using an inkjet process to form a black matte coating with a thickness of 30 μm.

[0135] The LED display screen packaged in this embodiment has good long-term reliability and light uniformity. After being placed outdoors for 30 days, no yellowing, color cast, or screen defects occur, and the light transmittance reaches 90.5%.

[0136] Example 4

[0137] The difference between Example 4 and Example 3 is that the composition ratio of the epoxy resin composition is different.

[0138] The epoxy resin composition of this embodiment includes, by weight, 10 parts of an alicyclic epoxy resin (4-vinyl-1-cyclohexene diepoxide), 30 parts of a hydantoin epoxy resin (5,5-dimethyl-β-methylhydantoin epoxy resin), 40 parts of an anhydride curing agent (hexahydrophthalic anhydride and methylhexahydrophthalic anhydride in a 1:1 mass ratio), 10 parts of amino-modified silica, 0.3 parts of a curing accelerator, and 1 part of an antioxidant. The curing accelerator is ethyl levulinate and triethylenetetramine in a 2:1 mass ratio. The antioxidant is Antioxidant 1010 and Antioxidant 168 in a 1:2 mass ratio.

[0139] The preparation of amino-modified silica involves adding 90 parts of a solvent (a mixture of ethanol and water in a 1:1 mass ratio) and 5 parts of an amino modifier (a mixture of triethylenetetramine and boron amine in a 1:4 mass ratio) to a reaction kettle, stirring at 50°C for 0.5 hours, then slowly adding 5 parts of silica microspheres (particle size 2-10 microns), and continuing stirring at 50°C for 4 hours. After the reaction is completed, the precipitate is separated using a centrifuge, and the solvent in the precipitate is dried in an oven to obtain amino-modified silica.

[0140] The preparation method of the epoxy resin composition and the preparation method of the LED display screen in Example 4 are the same as those in Example 3.

[0141] Example 5

[0142] The difference between Example 5 and Example 3 is that the composition ratio of the epoxy resin composition is different.

[0143] The epoxy resin composition of this embodiment includes, by weight, 60 parts of an alicyclic epoxy resin (4-vinyl-1-cyclohexene diepoxide), 30 parts of a hydantoin epoxy resin (5,5-dimethylhydantoin epoxy resin), 40 parts of an anhydride curing agent (hexahydrophthalic anhydride and methylhexahydrophthalic anhydride in a 1:1 mass ratio), 10 parts of amino-modified silica, 0.3 parts of a curing accelerator, and 1 part of an antioxidant. The curing accelerator is ethyl levulinate and triethylenetetramine in a 2:1 mass ratio. The antioxidant is Antioxidant 1010 and Antioxidant 168 in a 1:2 mass ratio.

[0144] The preparation of amino-modified silica includes adding 90 parts of a solvent (a mixture of ethanol and water in a 1:1 mass ratio) and 5 parts of an amino modifier (a mixture of triethylenetetramine and boron amine in a 1:4 mass ratio) to a reaction kettle, stirring at 50°C for 0.5 hours, then slowly adding 5 parts of silica microspheres, and continuing to stir at 50°C for 4 hours. After the reaction is completed, the precipitate is separated by centrifugation, and the solvent in the precipitate is dried in an oven to obtain amino-modified silica.

[0145] The preparation method of the epoxy resin composition and the preparation method of the LED display screen in Example 5 are the same as those in Example 3.

[0146] Comparative Example 1

[0147] The difference between this comparative example and Example 3 is that the composition ratio of the epoxy resin composition is different.

[0148] The epoxy resin composition of this comparative example comprises, by weight, 65 parts of an alicyclic epoxy resin (4-vinyl-1-cyclohexene diepoxide), 5 parts of a hydantoin epoxy resin (5,5-dimethylhydantoin epoxy resin), 40 parts of an anhydride curing agent (hexahydrophthalic anhydride and methylhexahydrophthalic anhydride in a 1:1 mass ratio), 10 parts of amino-modified silica, 0.3 parts of a curing accelerator, and 1 part of an antioxidant. The curing accelerator is ethyl levulinate and triethylenetetramine in a 2:1 mass ratio. The antioxidant is Antioxidant 1010 and Antioxidant 168 in a 1:2 mass ratio. The preparation of amino-modified silica includes adding 90 parts of a solvent (a mixture of ethanol and water in a 1:1 mass ratio) and 5 parts of an amino modifier (a mixture of triethylenetetramine and boron amine in a 1:4 mass ratio) to a reaction kettle, stirring at 50°C for 0.5 hours, then slowly adding 5 parts of silica microspheres, and continuing to stir at 50°C for 4 hours. After the reaction is completed, the precipitate is separated by centrifugation, and the solvent in the precipitate is dried in an oven to obtain amino-modified silica.

[0149] The preparation method of the epoxy resin composition and the preparation method of the LED display screen in this comparative example are the same as those in Example 3.

[0150] Comparative Example 2

[0151] The difference between this comparative example and Example 3 is that the composition ratio of the epoxy resin composition is different.

[0152] The epoxy resin composition of this comparative example comprises, by weight, 10 parts of an alicyclic epoxy resin (4-vinyl-1-cyclohexene diepoxide), 40 parts of a hydantoin epoxy resin (5,5-dimethylhydantoin epoxy resin), 40 parts of an anhydride curing agent (hexahydrophthalic anhydride and methylhexahydrophthalic anhydride in a 1:1 mass ratio), 10 parts of amino-modified silica, 0.3 parts of a curing accelerator, and 1 part of an antioxidant. The curing accelerator is ethyl levulinate and triethylenetetramine in a 2:1 mass ratio. The antioxidant is Antioxidant 1010 and Antioxidant 168 in a 1:2 mass ratio. The preparation of amino-modified silica includes adding 90 parts of a solvent (a mixture of ethanol and water in a 1:1 mass ratio) and 5 parts of an amino modifier (a mixture of triethylenetetramine and boron amine in a 1:4 mass ratio) to a reaction kettle, stirring at 50°C for 0.5 hours, then slowly adding 5 parts of silica microspheres, and continuing to stir at 50°C for 4 hours. After the reaction is completed, the precipitate is separated by centrifugation, and the solvent in the precipitate is dried in an oven to obtain amino-modified silica.

[0153] The preparation method of the epoxy resin composition and the preparation method of the LED display screen in this comparative example are the same as those in Example 3.

[0154] Comparative Example 3

[0155] The difference between this comparative example and Example 3 is that the epoxy resin composition does not contain amino-modified silica.

[0156] The epoxy resin composition of this comparative example comprises, by weight, 40 parts of an alicyclic epoxy resin (4-vinyl-1-cyclohexene diepoxide), 30 parts of a hydantoin epoxy resin (5,5-dimethylhydantoin epoxy resin), 40 parts of an anhydride curing agent (hexahydrophthalic anhydride and methylhexahydrophthalic anhydride in a 1:1 mass ratio), 0.3 parts of a curing accelerator, and 1 part of an antioxidant. The curing accelerator is ethyl levulinate and triethylenetetramine in a 2:1 mass ratio. The antioxidant is Antioxidant 1010 and Antioxidant 168 in a 1:2 mass ratio.

[0157] The preparation method of the epoxy resin composition and the preparation method of the LED display screen in this comparative example are the same as those in Example 3.

[0158] Comparative Example 4

[0159] The difference between this comparative example and Example 3 is that the amino-modified silica in the epoxy resin composition is replaced by silica microspheres that are not amino-modified.

[0160] The epoxy resin composition of this comparative example comprises, by weight, 40 parts of an alicyclic epoxy resin (4-vinyl-1-cyclohexene diepoxide), 30 parts of a hydantoin epoxy resin (5,5-dimethylhydantoin epoxy resin), 40 parts of an anhydride curing agent (hexahydrophthalic anhydride and methylhexahydrophthalic anhydride in a 1:1 ratio), 10 parts of silica microspheres (particle size 2-10 μm), 0.3 parts of a curing accelerator, and 1 part of an antioxidant. The curing accelerator is ethyl levulinate and triethylenetetramine in a 2:1 ratio. The antioxidant is Antioxidant 1010 and Antioxidant 168 in a 1:2 ratio.

[0161] The preparation method of the epoxy resin composition and the preparation method of the LED display screen in this comparative example are the same as those in Example 3.

[0162] The LED display screens prepared in Examples 1 to 5 and Comparative Examples 1 to 4 were placed outdoors for 30 days and then tested for their light transmittance and water absorption.

[0163] The light transmittance is measured using a light transmittance tester.

[0164] The test method for water absorption is: using the national standard test method GBT1034 1998: place a standard size product in 100℃ water and heat it for one hour, measure the difference in mass before and after heating, and thus obtain the water absorption rate.

[0165] The test results are recorded in Table 1.

[0166] Table 1

[0167] Serial number Light transmittance after 30 days of outdoor placement (%) Water absorption (%) Example 1 90 1.1 Example 2 88.9 1.0 Example 3 90.5 0.9 Example 4 87.7 0.5 Example 5 92.2 1.8 Comparative Example 1 92.4 1.7 Comparative Example 2 87.2 0.4 Comparative Example 3 93.5 (glare occurs) 1.1 Comparative Example 4 85.2 1.4

[0168] As can be seen from the data in Table 1, the LED displays of Examples 1 to 5 had a light transmittance of 87.7% to 92.2% and a water absorption rate of 0.5% to 1.8% after 30 days of outdoor placement, demonstrating both good light uniformity and water resistance. The LED display of Comparative Example 1 had a light transmittance of 92.4% and a water absorption rate of 1.7% after 30 days of outdoor placement, but the long-term stability of the LED display of Comparative Example 1 was poor. The LED display of Comparative Example 2 had a light transmittance of 87.2% and a water absorption rate of 0.4% after 30 days of outdoor placement, failing to achieve both good light uniformity and water resistance. The LED display of Comparative Example 3 had a light transmittance of 93.5% after 30 days of outdoor placement, showing high transmittance but with glare. Its water absorption rate was 1.1%, and its overall performance was inferior to that of the LED display of Example 3. The LED display of Comparative Example 4 had a light transmittance of 85.2% and a water absorption rate of 1.4% after 30 days of outdoor placement, demonstrating inferior overall performance to that of the LED display of Example 3.

[0169] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0170] The embodiments described above only express several implementation methods of the present invention, which are convenient for understanding the technical solutions of the present invention in a specific and detailed manner, but they cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, several variations and improvements can be made, which all fall within the scope of protection of the present invention. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided by the present invention are all within the scope of protection of the attached claims described in the present invention. Therefore, the scope of protection of the patent of the present invention shall be based on the content of the attached claims, and the description and drawings can be used to interpret the content of the claims.

Claims

1. An epoxy resin composition, characterized in that Calculated by mass, its components include: 10 to 60 parts of alicyclic epoxy resin, 10 to 30 parts of hydantoin epoxy resin, 5 to 10 parts of amino-modified silica, and 10 to 50 parts of anhydride curing agent; The preparation method of the amino-modified silica comprises: Mix the amino modifier, solvent and silica microspheres and react at 45°C to 60°C for 3h to 5h; The amino modifier includes at least one of ethylenediamine, diethylenetriamine, triethylenetetramine and boron amine compounds; The alicyclic epoxy resin includes at least one of cyclohexane-1,2-dicarboxylic acid diglycidyl ester, 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester, and 4-vinyl-1-cyclohexene diepoxide.

2. The epoxy resin composition according to claim 1, wherein The hydantoin epoxy resin includes at least one of 5-methyl-5-ethylhydantoin epoxy resin, 5-phenylhydantoin epoxy resin and 5,5-dimethylhydantoin epoxy resin.

3. The epoxy resin composition according to claim 1, wherein The acid anhydride curing agent includes at least one of methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride and methylhexahydrophthalic anhydride.

4. The epoxy resin composition according to any one of claims 1 to 3, characterized in that The epoxy resin composition further comprises at least one of a curing accelerator and an antioxidant; the epoxy resin composition satisfies at least one of the conditions (1) to (4): (1) The mass fraction of the curing accelerator is 0.1 to 1 part; (2) the curing accelerator comprises at least one of ethyl levulinate and triethylenetetramine; (3) The weight percentage of the antioxidant is 0.05 to 1 part; (4) The antioxidant includes at least one of antioxidant 1010, antioxidant 1076 and antioxidant 168.

5. The method for preparing the epoxy resin composition according to any one of claims 1 to 4, characterized in that: The following steps are involved: Mixing a cycloaliphatic epoxy resin and a hydantoin epoxy resin to prepare a first mixture; Mixing an anhydride curing agent and amino-modified silica to prepare a second mixture; The first mixture and the second mixture are mixed to prepare the epoxy resin composition.

6. Use of the epoxy resin composition according to any one of claims 1 to 4 in the preparation of LED display screens.

7. A packaging method for an LED display screen, characterized in that: The following steps are involved: Covering the surface of the LED display module with the epoxy resin composition according to any one of claims 1 to 4 to prepare an encapsulation layer; The encapsulation layer is cured.

8. The packaging method of the LED display according to claim 7, characterized in that: After the step of curing the encapsulation layer, the method further includes: performing vacuum plasma treatment on the surface of the cured encapsulation layer; A black matte coating is prepared on the surface of the packaging layer that has been subjected to vacuum plasma treatment.

9. The packaging method of an LED display screen according to claim 7 or 8, characterized in that: The curing process includes a first curing process and a second curing process; the curing process satisfies at least one of the conditions (1) to (4): (1) The temperature of the first curing treatment is 70°C to 90°C; (2) The first curing treatment time is 0.5h to 1h; (3) The temperature of the second curing treatment is 110° C. to 140° C.; (4) The second curing treatment time is 1 hour to 2 hours.

10. An LED display screen, characterized in that: The packaging structure comprises a packaging layer made from the epoxy resin composition according to any one of claims 1 to 4.

11. An electronic product, characterized in that: Including the LED display screen according to claim 10.

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