Two-component epoxy adhesive, preparation method and application thereof

Abstract

The present application relates to a kind of two-component epoxy glue and its preparation method and application, the two-component epoxy glue includes A component and B component, the preparation raw material of the A component includes epoxy resin A, epoxy resin B, active diluent and anti-aging agent, the epoxy resin B is flexible epoxy resin with specific structure, the preparation raw material of the B component includes alicyclic amine curing agent, polyether amine curing agent and curing accelerator.By the A component and B component with specific component are matched, the two-component epoxy glue prepared has excellent low-temperature warping resistance and cold-heat shock resistance, and it also has the advantages of room temperature fast curing, yellowing resistance, and the problem of unit board warping at low temperature is well solved.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic packaging, and in particular to a two-component epoxy adhesive and a preparation method and application thereof. Background Art

[0002] As the demand for smart displays increases, the technology for enhancing the protection of LED display screens is also constantly being strengthened. GOB, which stands for Glue on the board, is a packaging technology introduced to solve the problem of protecting the lamp beads of LED display screens. GOB is a surface glue filling process that uses advanced transparent materials to encapsulate the PCB substrate and LED packaging unit, thereby forming an effective protection and thus increasing the service life of the display screen in outdoor environments. Through the GOB process, the granular pixels on the surface of the original light board are transformed into an overall flat light board, realizing the transformation from point light source to surface light source, making the product's light emission more uniform, significantly improving the product's contrast, reducing glare and harshness, and alleviating visual fatigue.

[0003] CN104804691A discloses a room-temperature curing, high-temperature-resistant, and high-toughness epoxy adhesive and its preparation method. This solution achieves excellent toughness by using ordinary epoxy resin, nano-core-shell rubber particles to modify the epoxy toughening agent, and a polyamide curing agent. However, the addition of the nano-core-shell rubber particles prevents the epoxy adhesive from achieving the technical effect of being colorless and transparent.

[0004] CN117285897A discloses an epoxy resin sealant. The raw materials of the epoxy resin sealant include component A and component B, wherein component A contains epoxy resin, and component B contains a polyetheramine with a molecular weight of 200 to 2500, an antioxidant, a UV absorber, and a diluent. The epoxy resin sealant cures rapidly at medium and low temperatures and exhibits good toughness, high light transmittance, and low warpage at room temperature. However, it exhibits poor warpage at low temperatures.

[0005] Currently, applications are experiencing issues such as unit boards warping or even falling off at low temperatures (≤-20°C), and unit boards separating from the colloid after 100 cycles of thermal shock (-40 to 120°C). Therefore, the issue of unit board warping at low temperatures has been a pressing technical challenge for those skilled in the art. Summary of the Invention

[0006] To address the above-mentioned technical problems, the present invention provides a two-component epoxy adhesive, its preparation method, and application. By combining component A and component B with specific compositions, the resulting two-component epoxy adhesive exhibits excellent resistance to low-temperature warping and thermal shock. Furthermore, it offers the advantages of rapid room-temperature curing and yellowing resistance, effectively resolving the problem of unit board warping at low temperatures.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a two-component epoxy adhesive, the two-component epoxy adhesive comprising component A and component B;

[0009] The raw materials for preparing the A component include epoxy resin A, epoxy resin B, reactive diluent and anti-aging agent;

[0010] The epoxy resin B is a flexible epoxy resin having the following general structural formula:

[0011]

[0012] wherein R1 and R2 are each independently selected from -CH3 or -H; 0≤a≤10, 0≤b≤10, a+b>0;

[0013] The raw materials for preparing the B component include alicyclic amine curing agent, polyether amine curing agent and curing accelerator.

[0014] The two-component epoxy adhesive provided by the present invention includes components A and B. Component A, as the main agent, is prepared by combining epoxy resin A, epoxy resin B, a reactive diluent, and an anti-aging agent, with the epoxy resin B being a flexible epoxy resin. Component B, as the curing agent, is prepared by combining an alicyclic amine curing agent, a polyetheramine curing agent, and a curing accelerator. By combining components A and B, the resulting two-component epoxy adhesive exhibits excellent resistance to low-temperature warping and thermal shock, while also offering the advantages of rapid room-temperature curing and yellowing resistance.

[0015] In component A of the present invention, epoxy resin B is defined as a flexible epoxy resin having a specific structure. The specific structure contains elastic units of the -O-CH(CH3)-C- structure, which makes the molecular chain easy to rotate. Under the thermal stress caused by low temperature / hot and cold shock, the molecular chain conformation can be changed, thereby achieving the effect of stress relief and good flexibility. Therefore, the specifically selected epoxy resin B of the present invention has good flexibility and can effectively release the thermal stress of the epoxy adhesive, which is beneficial to reducing the warping of the GOB epoxy coating adhesive-display unit board composite material in low temperature environments.

[0016]

[0017] wherein R1 and R2 are each independently selected from -CH3 or -H; 0≤a≤10, 0≤b≤10, a+b>0;

[0018] 0≤a≤10, for example, a can be 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, etc.; 0≤b≤10, for example, b can be 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, etc.

[0019] Preferably, the raw materials for preparing component A in the two-component epoxy adhesive include the following components in parts by weight:

[0020]

[0021] The raw materials for preparing component B in the two-component epoxy adhesive include the following components in parts by weight:

[0022] 50-80 parts by weight of alicyclic amine curing agent

[0023] 9-30 parts by weight of polyetheramine curing agent

[0024] 2 to 10 parts by weight of curing accelerator.

[0025] In the present invention, the epoxy resin A in component A is 40 to 80 parts by weight, for example, 43 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight or 78 parts by weight.

[0026] The epoxy resin B is 15 to 35 parts by weight, for example, 16 parts by weight, 18 parts by weight, 20 parts by weight, 22 parts by weight, 24 parts by weight, 26 parts by weight, 28 parts by weight, 30 parts by weight, or 32 parts by weight.

[0027] The active diluent is 10 to 35 parts by weight, for example, 12 parts by weight, 14 parts by weight, 16 parts by weight, 18 parts by weight, 20 parts by weight, 22 parts by weight, 25 parts by weight, 28 parts by weight, 30 parts by weight or 32 parts by weight.

[0028] The amount of the anti-aging agent is 0.2 to 3 parts by weight, for example, 0.5 parts by weight, 0.8 parts by weight, 1 part by weight, 1.2 parts by weight, 1.5 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.2 parts by weight, 2.5 parts by weight or 2.8 parts by weight.

[0029] The alicyclic amine curing agent in component B is 50 to 80 parts by weight, for example, 53 parts by weight, 55 parts by weight, 58 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 72 parts by weight, 75 parts by weight or 78 parts by weight.

[0030] The polyetheramine curing agent is 9 to 30 parts by weight, for example, 12 parts by weight, 14 parts by weight, 16 parts by weight, 18 parts by weight, 20 parts by weight, 22 parts by weight, 24 parts by weight, 26 parts by weight or 28 parts by weight.

[0031] The curing accelerator is 2 to 10 parts by weight, for example, 2.5 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight or 9.5 parts by weight.

[0032] Preferably, the epoxy equivalent of the epoxy resin A is 160 to 250 g / eq, for example, 165 g / eq, 170 g / eq, 180 g / eq, 190 g / eq, 200 g / eq, 210 g / eq, 220 g / eq, 230 g / eq, 240 g / eq or 245 g / eq.

[0033] Preferably, the epoxy resin A includes any one of bisphenol A diglycidyl ether, bisphenol F epoxy resin, aliphatic epoxy resin, alicyclic epoxy resin or novolac epoxy resin, or a combination of at least two thereof.

[0034] In the present invention, the epoxy resin A is further preferably NPEL-128, E51 and / or E44 bisphenol A epoxy resin.

[0035] Preferably, the epoxy equivalent of the epoxy resin B is 265 to 400 g / eq, for example, 270 g / eq, 280 g / eq, 290 g / eq, 300 g / eq, 320 g / eq, 340 g / eq, 360 g / eq, 380 g / eq or 390 g / eq.

[0036] In the present invention, the flexible epoxy resin is further preferably EP4000S and / or EP-4003S from ADEKA of Japan.

[0037] Preferably, the reactive diluent is an epoxy diluent;

[0038] The epoxy diluent includes any one of butyl glycidyl ether, benzyl glycidyl ether, octyl glycidyl ether, dodecyl glycidyl ether, tridecyl glycidyl ether, tetradecyl glycidyl ether, 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether or 1,6-hexanediol diglycidyl ether, or a combination of at least two thereof.

[0039] In component A of the present invention, the reactive diluents selected with specific structures all have epoxy structures, which can cooperate with epoxy resin A and epoxy resin B to exert a synergistic effect, so that the obtained product has good leveling and viscosity, which can meet the needs of actual production.

[0040] The anti-aging agent includes an antioxidant and / or an ultraviolet absorber.

[0041] In the present invention, the antioxidant includes any one of MARK AO-50, IRGANOX 1010 or IRGANOX 1135 manufactured by ADEKA of Japan, or a combination of at least two thereof.

[0042] The ultraviolet absorber includes any one of Eversorb EP4, Eversorb EP4S, Eversorb EP5S, Eversorb EP5C, UV-531 or UV-327 of Everlight Chemical, or a combination of at least two thereof.

[0043] Preferably, the component A further comprises a defoaming agent and / or a coupling agent.

[0044] Preferably, the defoaming agent includes any one of BYK-1799, BYK525, BYK530 or BYK535 from BYK Chemical, or a combination of at least two thereof; its content is 0 to 2.0 parts by weight, for example, 0.2 parts by weight, 0.4 parts by weight, 0.6 parts by weight, 0.8 parts by weight, 1.0 parts by weight, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight or 2.0 parts by weight, etc.

[0045] In the present invention, by selecting and compounding specific components, the viscosity of the system is reduced, and a two-component epoxy adhesive with good leveling properties and no bubbles after curing can be obtained without adding a defoaming agent.

[0046] Preferably, the coupling agent includes any one of a silane coupling agent and BYK4511, or a combination of at least two thereof; the content of the coupling agent is 0 to 1 part by weight, for example, 0.1 part by weight, 0.2 part by weight, 0.3 part by weight, 0.4 part by weight, 0.5 part by weight, 0.6 part by weight, 0.7 part by weight, 0.8 part by weight, 0.9 part by weight or 1 part by weight, etc.

[0047] In the present invention, the main purpose of adding the coupling agent is to further improve the bonding performance between the two-component epoxy adhesive and the substrate. Even without adding the coupling agent, a two-component epoxy adhesive with good resistance to cold and hot shock, low-temperature warping and yellowing can be obtained.

[0048] Preferably, the mass ratio of the alicyclic amine curing agent to the polyetheramine curing agent is (2.5-7.4):1, for example, it can be 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 7:1 or 7.4:1.

[0049] In the present invention, component B uses a specific alicyclic amine curing agent and a polyetheramine curing agent for combination use, so that the two can play a good synergistic role, thereby making the resulting two-component epoxy adhesive have good resistance to cold and hot shock, resistance to low-temperature warping and yellowing. Furthermore, the technical effect of the resulting two-component epoxy adhesive can be further improved by combining curing agents in a specific mass ratio. When the mass ratio of the alicyclic amine curing agent to the polyetheramine curing agent is lower than 2.5:1, that is, the content of the polyetheramine curing agent is too high, at this time the cross-linking density is low, the cohesive strength is weak, the epoxy adhesive is prone to cracking, and the wear resistance of the epoxy adhesive will also deteriorate; when the mass ratio of the two is higher than 7.4:1, that is, the content of the alicyclic amine curing agent is too high, the resulting two-component epoxy adhesive is poor in flexibility and prone to yellowing.

[0050] The amine value of the alicyclic amine curing agent is 500-600 mgKOH / g, for example, it can be 510 mgKOH / g, 520 mgKOH / g, 530 mgKOH / g, 540 mgKOH / g, 550 mgKOH / g, 560 mgKOH / g, 570 mgKOH / g, 580 mgKOH / g or 590 mgKOH / g; the active hydrogen equivalent is 50-70 g / eq, for example, it can be 52 g / eq, 54 g / eq, 56 g / eq, 58 g / eq, 60 g / eq, 62 g / eq, 64 g / eq, 66 g / eq or 68 g / eq.

[0051] Preferably, the alicyclic amine curing agent includes any one of R5911-8, H-3316, H-1608, H-825 or H-826 of Shenzhen Xuhua Biotechnology Co., Ltd., or a combination of at least two thereof.

[0052] In the present invention, the use of alicyclic amine curing agents can, to a certain extent, reduce the yellowing degree of the epoxy adhesive after heat aging and UV aging.

[0053] Preferably, the polyetheramine curing agent includes any one of EC130, D230, D400 or D2000, or a combination of at least two thereof.

[0054] In the present invention, the use of polyetheramine curing agent can appropriately increase the flexibility of the epoxy adhesive, reduce the hardness of the epoxy adhesive, and also reduce the yellowing degree of the epoxy adhesive after heat aging and UV aging, thereby ensuring the colorless and transparent characteristics of the epoxy adhesive.

[0055] Preferably, the curing accelerator includes any one of K54, dodecylphenol or N,N'-bis(3-aminopropyl)-ethylenediamine (CAS: 10563-26-5) or a combination of at least two thereof.

[0056] In the present invention, the use of a curing accelerator can accelerate the reaction rate of room temperature / heat curing, thereby improving construction efficiency.

[0057] Preferably, the mass ratio of component A to component B is (2-5):1.

[0058] In the present invention, components A and B are combined in a specific mass ratio during use, resulting in a two-component epoxy adhesive with excellent low-temperature warpage resistance and thermal shock resistance. When the mass ratio is less than 2:1, the stoichiometric ratio of the epoxy resin and amine curing agent is imbalanced, and excess amine shortens the working time. Furthermore, the resulting two-component epoxy adhesive is prone to yellowing after curing. When the mass ratio is greater than 5:1, the stoichiometric ratio of the epoxy resin and amine curing agent is imbalanced, resulting in prolonged working time, affecting application efficiency, and incomplete curing, making it unable to protect electronic devices.

[0059] In a second aspect, the present invention provides a method for preparing the two-component epoxy adhesive as described in the first aspect, the preparation method comprising the following steps:

[0060] (1) preparing component A: mixing epoxy resin A, epoxy resin B, a reactive diluent, an anti-aging agent, an optional coupling agent, and an optional defoaming agent to obtain component A;

[0061] (2) Preparation of component B: Mixing an alicyclic amine curing agent, a polyetheramine curing agent and a curing accelerator to obtain the component B.

[0062] In the present invention, the preparation method of the two-component epoxy adhesive specifically includes the following steps:

[0063] (1) preparing component A: mixing epoxy resin A, epoxy resin B, a reactive diluent, an anti-aging agent, an optional coupling agent, and an optional defoaming agent, stirring at a speed of 25 to 35 rpm for 25 to 60 minutes, and finally evacuating the mixture and continuing to stir at a speed of 25 to 35 rpm for 15 to 25 minutes to obtain component A;

[0064] (2) Preparation of component B: Mix the alicyclic amine curing agent, the polyetheramine curing agent and the curing accelerator, stir at a speed of 25 to 35 rpm for 15 to 40 minutes, and finally evacuate and continue stirring at a speed of 25 to 35 rpm for 15 to 25 minutes to obtain the component B.

[0065] In the present invention, component A and component B are first prepared separately according to a specific preparation method. During storage, component A and component B are stored separately. During use, component A and component B are directly blended to obtain a two-component epoxy adhesive with good operability, so that its performance is optimized and the performance is not weakened due to excessive storage time. In addition, the two-component epoxy adhesive of the present invention does not require additional toughening agents and fillers during the preparation process, and the raw materials are simple, economical and easily available. At the same time, the preparation method is simple to operate, and the obtained two-component epoxy adhesive has low viscosity and good leveling properties, can meet the requirements of actual production, and has good practicality.

[0066] In a third aspect, the present invention provides a use of the two-component epoxy adhesive as described in the first aspect in electronic packaging products.

[0067] Compared with the prior art, the present invention has at least the following beneficial effects:

[0068] (1) The present invention adopts a combination of component A and component B with specific components, so that the prepared two-component epoxy adhesive has excellent resistance to low-temperature warping and thermal shock, and has the advantages of rapid curing at room temperature and yellowing resistance, thereby solving the problem of unit board warping at low temperatures;

[0069] (2) The selection of the epoxy resin B with a specific structure in component A of the present invention can further improve the low-temperature warping resistance of the two-component epoxy adhesive and significantly improve its yellowing resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 It is a classification chart of yellowing degree;

[0071] Figure 2 This is a classification chart of the degree of warping at -32℃ low temperature. DETAILED DESCRIPTION

[0072] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through 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 shall be subject to the claims.

[0073] Some of the raw material information used in the following examples is shown in Table 1.

[0074] Table 1

[0075] Materials List Brand Supplier Name Epoxy Resin A NPEL-128 Nan Ya epoxy resin, epoxy equivalent weight is 186g / eq Epoxy resin B EP-4003S Japan ADEKA Company, epoxy equivalent is 320g / eq Reactive diluent XY622 Anhui Xinyuan Technology Co., Ltd., epoxy equivalent weight is 115geq Anti-aging agents TP-10H China Taiwan Double Bond Chemical Co., Ltd. defoaming agent BYK-1799 BYK coupling agent BYK4511 BYK Alicyclic amine curing agent R5911-8 Rich Chemical Co., Ltd., AHEW = 63g / cq, amine value 562mgKOHg Polyetheramine curing agent EC130 BASF, AHEW=56g / eq curing accelerator K54 EVONIK Chemistry

[0076] Examples 1-14, Comparative Examples 1-7

[0077] A two-component epoxy adhesive is obtained by blending component A and component B in a mass ratio of 10:3.

[0078] The raw materials for preparing component A and component B are shown in Table 2, and the dosage units of each component are "parts by weight".

[0079] Table 2

[0080]

[0081] Example 15

[0082] This embodiment provides a two-component epoxy adhesive, which differs from Example 1 in that the mass ratio of component A to component B is adjusted from 10:3 to 5:3, wherein the preparation raw materials and contents of component A and component B are the same as those in Example 1.

[0083] Example 16

[0084] This embodiment provides a two-component epoxy adhesive, which differs from Example 1 in that the mass ratio of component A to component B is adjusted from 10:3 to 2:1, wherein the preparation raw materials and contents of component A and component B are the same as those in Example 1.

[0085] Example 17

[0086] This embodiment provides a two-component epoxy adhesive, which differs from Example 1 in that the mass ratio of component A to component B is adjusted from 10:3 to 5:1, wherein the preparation raw materials and contents of component A and component B are the same as those in Example 1.

[0087] Example 18

[0088] This embodiment provides a two-component epoxy adhesive, which differs from Example 1 in that the mass ratio of component A to component B is adjusted from 10:3 to 16:3, wherein the preparation raw materials and contents of component A and component B are the same as those in Example 1.

[0089] Example 19

[0090] This embodiment provides a two-component epoxy adhesive, which differs from Example 1 in that the defoaming agent in component A is replaced by a coupling agent, and the other raw materials and contents are the same as those in Example 1.

[0091] Example 20

[0092] This embodiment provides a two-component epoxy adhesive, which differs from Example 1 in that 0.5 parts by weight of the defoamer in component A is replaced by a combination of 0.3 parts by weight of a defoamer and 0.2 parts by weight of a coupling agent, and the other raw materials and contents are the same as those in Example 1.

[0093] Example 21

[0094] This embodiment provides a two-component epoxy adhesive, which differs from Example 1 in that no defoaming agent is added to component A, and other raw materials and contents are the same as those in Example 1.

[0095] Comparative Example 8

[0096] This comparative example provides a two-component epoxy adhesive, which differs from Example 3 only in that epoxy resin B (EP-4003S) is replaced by Japan DIC's new flexible liquid epoxy resin EXA-4850, and other raw materials and contents are the same as those in Example 3.

[0097] The preparation methods of the two-component epoxy adhesives provided in Examples 1-21 and Comparative Examples 1-8 both include the following steps:

[0098] (1) Preparing component A: epoxy resin A, epoxy resin B, reactive diluent, anti-aging agent, optional coupling agent, and optional defoaming agent were mixed, stirred at 30 rpm for 40 minutes, and then vacuumed and continued to mix at 25 rpm for 20 minutes to obtain component A;

[0099] (2) preparing component B: mixing an alicyclic amine curing agent, a polyetheramine curing agent, and a curing accelerator, stirring at a speed of 25 rpm for 30 minutes, and finally evacuating the mixture (vacuum degree of -0.095 MPa) and continuing to stir at a speed of 25 rpm for 15 minutes to obtain component B;

[0100] The two-component epoxy adhesives prepared in Examples 1-21 and Comparative Examples 1-8 were tested as follows:

[0101] (1) Hardness: The test was carried out in accordance with the standard GB / T 2411-2008 Plastics and hard rubber - Determination of indentation hardness (Shore hardness) using a durometer. The thickness of the sample was 6 mm.

[0102] (2) Cracking resistance: Two-component epoxy adhesive was applied to the LED display unit board, cured at room temperature for 48 hours, and then baked in a 100°C oven for 0.5 hours to achieve complete curing and eliminate thermal stress. The unit board was subjected to a thermal shock test at -40°C / 120°C, 1 hour per cycle, for a total of 100 cycles.

[0103] (3) Evaluation of yellowing degree: Drop the glue on a glass slide, cure it at 100℃ for 0.5h, and then bake it at 200℃ for 6h. Figure 1 The yellowing resistance is graded according to the yellowing degree classification chart shown in the figure, 1 to 2 has good yellowing resistance, and 4 to 5 has poor yellowing resistance.

[0104] (4) Evaluation of low temperature warpage: Apply two-component epoxy glue to the LED display unit board, cure it at room temperature for 48 hours, and then bake it in a 100℃ oven for 0.5 hours to achieve complete curing and eliminate thermal stress. Then put the unit board into a -32℃ freezer and lay it flat for 0.5 hours, take it out for observation, and then Figure 2 The -32°C low-temperature warpage classification chart shown grades the warpage of the unit board. Warpage levels 1 to 2 are relatively mild, while warpage levels 4 to 5 are significantly worse.

[0105] (5) Surface drying time: The test was carried out using the method in GB / T 13477.5-2002.

[0106] The test results are shown in Table 3.

[0107] Table 3

[0108]

[0109] The test results show that:

[0110] (1) It can be seen from Examples 1 to 21 that the present invention adopts a combination of component A and component B with specific components, so that the prepared two-component epoxy adhesive has excellent resistance to low-temperature warping and resistance to cold and hot shocks, and at the same time has the advantages of rapid curing at room temperature and resistance to yellowing, thereby solving the problem of unit board warping at low temperatures.

[0111] (2) By comparing Example 1 with Examples 5 to 7, it can be seen that the combination of alicyclic amine curing agent and polyetheramine curing agent in a specific mass ratio in component B can improve the low-temperature warping, thermal shock resistance and yellowing resistance of the obtained two-component epoxy adhesive to a certain extent. When the mass ratio of the two is lower than 2.5:1, the obtained two-component epoxy adhesive is relatively soft and has low bonding strength with the PCB unit board, resulting in cracking after thermal shock; when the mass ratio of the two is higher than 7.4:1, the warping at low temperature is aggravated and the yellowing resistance is reduced.

[0112] (3) By comparing Example 11 with Examples 1 to 4, it can be seen that when the raw materials of component A and component B are fixed, the content selection of specific raw materials is conducive to improving the cold and hot shock resistance of the obtained two-component epoxy adhesive.

[0113] (4) By comparing Example 2 with Examples 12 to 14, it can be seen that when the content of epoxy resin B in component A exceeds the specific content range of the present invention, the low-temperature warping resistance and thermal shock resistance of the obtained two-component epoxy adhesive are reduced; further, by comparing Example 3 with Comparative Example 4, it can be shown that when epoxy resin B is not added to component A, the low-temperature warping resistance and thermal shock resistance of the obtained two-component epoxy adhesive are reduced; in addition, by comparing Comparative Example 2 with Examples 1 to 4, it can be seen that under similar material ratios (i.e., the total content of epoxy resin A, epoxy resin B and active diluent in component A is fixed), flexible epoxy resin B is not added, and although the hardness of the obtained two-component epoxy adhesive is improved, due to its strong rigidity, the thermal stress between the two-component epoxy adhesive and the display unit board is difficult to release, and cracking is prone to occur during thermal shock. At the same time, warping is serious at low temperatures.

[0114] (5) By comparing Example 1 with Examples 15 to 18, it can be seen that the present invention can further improve the yellowing resistance of the two-component epoxy adhesive by adjusting the mass ratio of component A to component B, and at the same time can adjust the curing rate and surface drying time, thereby improving its practicality.

[0115] (6) By comparing Example 3 with Comparative Examples 5 and 6, it can be seen that when only a single alicyclic amine curing agent or polyetheramine curing agent is added to component B, the resulting two-component epoxy adhesive has poor resistance to low-temperature warping or resistance to cold and hot shock. Furthermore, by comparing Example 3 with Comparative Examples 3 and 7, it can be seen that when the alicyclic amine curing agent and the polyetheramine curing agent in component B are specifically formulated, a synergistic effect can be exerted, so that the resulting two-component epoxy adhesive can not only improve its resistance to low-temperature warping, but also have good yellowing resistance.

[0116] (7) By comparing Example 3 with Comparative Example 8, it can be seen that the addition of epoxy resin B, which is not of the specific structure of the present invention, significantly reduces the yellowing resistance of the obtained two-component epoxy adhesive and has no significant effect on its low-temperature warpage.

[0117] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A two-component epoxy adhesive, characterized in that: The two-component epoxy adhesive comprises component A and component B in a mass ratio of (2-5):1; The raw materials for preparing the A component include the following components in parts by weight: Epoxy resin A 40-80 parts by weight Epoxy resin B 15-35 parts by weight 10-35 parts by weight of active diluent 0.2-3 parts by weight of anti-aging agent; The epoxy resin B is a flexible epoxy resin having the following general structural formula: ； wherein R1 and R2 are each independently selected from -CH3 or -H; 0≤a≤10, 0≤b≤10, a+b>0; The raw materials for preparing the B component include the following components in parts by weight: 50-80 parts by weight of alicyclic amine curing agent 9-30 parts by weight of polyetheramine curing agent 2 to 10 parts by weight of a curing accelerator; The mass ratio of the alicyclic amine curing agent to the polyetheramine curing agent is (2.5-7.4):

1.

2. The two-component epoxy adhesive according to claim 1, characterized in that: The epoxy resin A includes any one of bisphenol A diglycidyl ether, bisphenol F epoxy resin, aliphatic epoxy resin, alicyclic epoxy resin or novolac epoxy resin, or a combination of at least two thereof.

3. The two-component epoxy adhesive according to claim 1, characterized in that: The epoxy equivalent of the epoxy resin B is 265-400 g / eq.

4. The two-component epoxy adhesive according to claim 1, characterized in that: The reactive diluent is an epoxy diluent; The epoxy diluent includes any one or a combination of at least two of butyl glycidyl ether, benzyl glycidyl ether, octyl glycidyl ether, dodecyl glycidyl ether, tridecyl glycidyl ether, tetradecyl glycidyl ether, 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether or 1,6-hexanediol diglycidyl ether; The anti-aging agent includes an antioxidant and / or an ultraviolet absorber.

5. The two-component epoxy adhesive according to claim 1, characterized in that: The A component further includes a defoaming agent and / or a coupling agent.

6. The two-component epoxy adhesive according to claim 1, characterized in that: The alicyclic amine curing agent has an amine value of 500-600 mgKOH / g and an active hydrogen equivalent of 50-70 g / eq.

7. A method for preparing a two-component epoxy adhesive according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: (1) Preparing component A: mixing epoxy resin A, epoxy resin B, a reactive diluent, an anti-aging agent, an optional coupling agent, and an optional defoaming agent to obtain the component A; (2) Preparing component B: mixing an alicyclic amine curing agent, a polyetheramine curing agent, and a curing accelerator to obtain the component B.

8. Use of the two-component epoxy adhesive according to any one of claims 1 to 6 in electronic packaging products.

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