Bi-component epoxy glue as well as preparation method and application thereof

Abstract

The invention relates to a bi-component epoxy adhesive and a preparation method and application thereof.The bi-component epoxy adhesive comprises a component A and a component B. The component A is prepared from epoxy resin A, epoxy resin B, a reactive diluent and an anti-aging agent, the epoxy resin B is flexible epoxy resin of a specific structure, and the reactive diluent is flexible epoxy resin of a specific structure. And the component B is prepared from the following raw materials: an alicyclic amine curing agent, a polyether amine curing agent and a curing accelerator. According to the present invention, the component A and the component B having the specific components are matched, such that the prepared two-component epoxy glue has characteristics of excellent low-temperature warping resistance and excellent cold and hot impact resistance, further has advantages of rapid curing at the room temperature and yellowing resistance, and well solves the problem of unit plate warping at the low temperature.

Description

Technical Field

[0001] The 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 protection enhancement technology for LED display screens is also constantly being strengthened. GOB, or 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 emit light more evenly, significantly improving the contrast of the product, reducing glare and glare, and alleviating visual fatigue.

[0003] CN104804691A discloses a room temperature curing high temperature resistant high toughness epoxy adhesive and a preparation method thereof. This solution can achieve excellent toughness by using ordinary epoxy resin, nano core-shell rubber particles to modify epoxy toughening agent, and polyamide curing agent, but due to the addition of nano core-shell rubber particles, it cannot achieve the technical effect of colorless and transparent epoxy adhesive.

[0004] CN117285897A discloses an epoxy resin sealant, the raw materials of which include component A and component B, wherein component A contains epoxy resin, and component B contains polyetheramine with a molecular weight of 200 to 2500, an antioxidant, an ultraviolet absorber and a diluent. The epoxy resin sealant can be quickly cured under medium and low temperature conditions, and has the advantages of good toughness, high light transmittance and low warpage at room temperature, but its warpage at low temperature is not good.

[0005] At present, problems such as the unit board warping or even falling off at low temperature (≤-20℃) and the unit board separating from the colloid after thermal shock (-40~120℃, 100 cycles) have appeared on the application side. Therefore, the problem of unit board warping at low temperature has always been a technical problem that needs to be solved urgently by technicians in this field. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a two-component epoxy adhesive and a preparation method and application thereof. By matching component A and component B having specific components, the prepared two-component epoxy adhesive has excellent resistance to low-temperature warping and resistance to cold and hot shocks, and also has the advantages of rapid curing and yellowing resistance at room temperature, which well solves 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 a component A and a 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, and the flexible epoxy resin has 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 comprises component A and component B, wherein the component A is used as a main agent, and is obtained by mixing epoxy resin A, epoxy resin B, reactive diluent and anti-aging agent, and the epoxy resin B is limited to be a flexible epoxy resin. The component B is a curing agent component, and is obtained by mixing alicyclic amine curing agent, polyether amine curing agent and curing accelerator. By mixing the specific components A and B, the prepared two-component epoxy adhesive has excellent resistance to low-temperature warping and cold and hot shock resistance, and has the advantages of rapid curing at room temperature and yellowing resistance.

[0015] In the component A of the present invention, epoxy resin B is defined as a flexible epoxy resin with a specific structure, and the elastic unit of -O-CH(CH3)-C- structure exists in the specific structure, so that the molecular chain can be easily rotated, and the molecular chain conformation can be changed under the thermal stress caused by low temperature / hot and cold shock, thereby achieving the effect of relieving stress and good flexibility. Therefore, the epoxy resin B specifically selected in the present invention has good flexibility, can effectively release the thermal stress of epoxy glue, and is conducive to reducing the warping of the GOB epoxy coating glue-display unit board composite material in a low temperature environment.

[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] Alicyclic amine curing agent 50-80 parts by weight Polyetheramine curing agent 9-30 parts by weight 2 to 10 parts by weight of curing accelerator.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] Preferably, the epoxy resin A includes any one of bisphenol A diglycidyl ether, bisphenol F epoxy resin, aliphatic epoxy resin, alicyclic epoxy resin or phenolic epoxy resin, or a combination of at least two thereof.

[0032] In the present invention, the epoxy resin A is further preferably NPEL-128, E51 and / or E44 bisphenol A type epoxy resin.

[0033] 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.

[0034] In the present invention, the flexible epoxy resin is further preferably EP4000S and / or EP-4003S from ADEKA of Japan.

[0035] Preferably, the reactive diluent is an epoxy diluent;

[0036] 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.

[0037] In component A of the present invention, the active diluents with specific structures all have epoxy structures, which can cooperate with epoxy resin A and epoxy resin B to exert synergistic effects, so that the obtained product has good leveling and viscosity, which can meet the needs of actual production.

[0038] The anti-aging agent includes an antioxidant and / or an ultraviolet absorber.

[0039] In the present invention, the antioxidant includes any one of MARK AO-50, IRGANOX 1010 or IRGANOX 1135 of ADEKA Japan, or a combination of at least two thereof.

[0040] 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.

[0041] Preferably, the A component further comprises a defoaming agent and / or a coupling agent.

[0042] Preferably, the defoaming agent includes any one of BYK-1799, BYK525, BYK530 or BYK535 of 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.

[0043] In the present invention, by selecting and compounding specific components, the viscosity of the system is low, and a two-component epoxy adhesive with good leveling properties and no bubbles after curing can be obtained without adding a defoaming agent.

[0044] Preferably, the coupling agent includes any one of a silane coupling agent and BYK4511, or a combination of at least two of them; the content of the coupling agent is 0 to 1 part by weight, for example, it can be 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.

[0045] 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. 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.

[0046] 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, etc.

[0047] In the present invention, component B uses a specific alicyclic amine curing agent and a polyetheramine curing agent for use in combination, so that the two can play a good synergistic role, so that the obtained two-component epoxy adhesive has good resistance to cold and hot shock, resistance to low-temperature warping and yellowing. Furthermore, the technical effect of the obtained 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 easy to crack, 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 two-component epoxy adhesive obtained at this time is not flexible and is easy to yellow.

[0048] 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, etc.; 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, etc.

[0049] 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.

[0050] In the present invention, the use of alicyclic amine curing agents can reduce the yellowing degree of epoxy adhesive after heat aging and UV aging to a certain extent.

[0051] Preferably, the polyetheramine curing agent includes any one of EC130, D230, D400 or D2000, or a combination of at least two thereof.

[0052] In the present invention, the use of polyetheramine curing agent can appropriately increase the flexibility of epoxy adhesive, reduce the hardness of epoxy adhesive, and also reduce the yellowing degree of epoxy adhesive after heat aging and UV aging, thereby ensuring the colorless and transparent characteristics of epoxy adhesive.

[0053] 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.

[0054] In the present invention, the use of a curing accelerator can accelerate the reaction rate of room temperature / heat curing, thereby improving the construction efficiency.

[0055] Preferably, the mass ratio of component A to component B is (2-5):1.

[0056] In the present invention, component A and component B are matched in a specific mass ratio during use, so that the obtained two-component epoxy adhesive has excellent resistance to low-temperature warping and cold and hot shock. When the mass ratio of the two is lower than 2:1, the stoichiometric ratio of the epoxy resin and the amine curing agent is imbalanced, and the excess amine will cause the operation time to be shortened, and the obtained two-component epoxy adhesive is prone to yellowing after curing; when the mass ratio of the two is higher than 5:1, the stoichiometric ratio of the epoxy resin and the amine curing agent is imbalanced, the operation time is too long, which affects the construction efficiency, and leads to incomplete curing, which cannot play a role in protecting electronic devices.

[0057] 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:

[0058] (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;

[0059] (2) Preparation of component B: Mixing an alicyclic amine curing agent, a polyether amine curing agent and a curing accelerator to obtain the component B.

[0060] In the present invention, the preparation method of the two-component epoxy adhesive specifically comprises the following steps:

[0061] (1) preparing component A: epoxy resin A, epoxy resin B, reactive diluent, anti-aging agent, optional coupling agent and optional defoaming agent are mixed, and the mixture is stirred at a speed of 25 to 35 rpm for 25 to 60 min. Finally, after vacuuming, the mixture is stirred at a speed of 25 to 35 rpm for 15 to 25 min to obtain component A;

[0062] (2) Preparation of component B: The alicyclic amine curing agent, the polyether amine curing agent and the curing accelerator are mixed, and the mixture is stirred at a speed of 25 to 35 rpm for 15 to 40 minutes. Finally, after vacuuming, the mixture is stirred at a speed of 25 to 35 rpm for 15 to 25 minutes to obtain the component B.

[0063] In the present invention, firstly, component A and component B are prepared separately according to a specific preparation method, and when stored, component A and component B are placed and stored separately; when used, component A and component B are directly blended to obtain a two-component epoxy adhesive with good operability, so that its performance is optimal and the performance is not weakened due to long storage time; in addition, the two-component epoxy adhesive of the present invention does not need to add additional toughening agents and fillers during the preparation process, and the raw materials are simple, economical and easy to obtain; 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.

[0064] In a third aspect, the present invention provides a use of the two-component epoxy adhesive as described in the first aspect in an electronic packaging product.

[0065] Compared with the prior art, the present invention has at least the following beneficial effects:

[0066] (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;

[0067] (2) The selection of 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

[0068] Figure 1 It is a classification chart of the degree of yellowing;

[0069] Figure 2 This is a classification chart of the degree of warping at -32℃ low temperature. DETAILED DESCRIPTION

[0070] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. However, the following examples are only 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.

[0071] Some of the raw material information used in the following examples is shown in Table 1.

[0072] Table 1

[0073] 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 Active diluent XY622 Anhui Xinyuan Technology Co., Ltd., epoxy equivalent 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 = 56 g / eq Curing accelerator K54 EVONIK Chemistry

[0074] Examples 1-14, Comparative Examples 1-7

[0075] A two-component epoxy adhesive is obtained by blending a component A and a component B in a mass ratio of 10:3.

[0076] 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".

[0077] Table 2

[0078]

[0079] Embodiment 15

[0080] This embodiment provides a two-component epoxy adhesive, which differs from Embodiment 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 Embodiment 1.

[0081] Example 16

[0082] This embodiment provides a two-component epoxy adhesive, which differs from Embodiment 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 Embodiment 1.

[0083] Embodiment 17

[0084] This embodiment provides a two-component epoxy adhesive, which differs from Embodiment 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 Embodiment 1.

[0085] Embodiment 18

[0086] This embodiment provides a two-component epoxy adhesive, which differs from Embodiment 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 Embodiment 1.

[0087] Embodiment 19

[0088] This embodiment provides a two-component epoxy adhesive, which differs from Embodiment 1 in that the defoaming agent in component A is replaced by a coupling agent, and other raw materials and contents are the same as those in Embodiment 1.

[0089] Embodiment 20

[0090] 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 other raw materials and contents are the same as those in Example 1.

[0091] Embodiment 21

[0092] This embodiment provides a two-component epoxy adhesive, which differs from Embodiment 1 in that no defoaming agent is added to Component A, and other raw materials and contents are the same as those in Embodiment 1.

[0093] Comparative Example 8

[0094] 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 a new flexible liquid epoxy resin EXA-4850 from Japan DIC, and other raw materials and contents are the same as those in Example 3.

[0095] The preparation methods of the two-component epoxy adhesives provided in Examples 1-21 and Comparative Examples 1-8 both include the following steps:

[0096] (1) preparing component A: epoxy resin A, epoxy resin B, reactive diluent, anti-aging agent, optional coupling agent and optional defoaming agent are mixed, and the mixture is stirred at a speed of 30 rpm for 40 min. Finally, after vacuuming, the mixture is stirred at a speed of 25 rpm for 20 min to obtain component A;

[0097] (2) preparing component B: mixing an alicyclic amine curing agent, a polyetheramine curing agent and a curing accelerator, mixing for 30 minutes at a stirring condition of 25 rpm, and finally evacuating the mixture (vacuum degree of -0.095 MPa), and then continuing to mix for 15 minutes at a stirring condition of 25 rpm to obtain component B;

[0098] The two-component epoxy adhesives prepared in Examples 1-21 and Comparative Examples 1-8 were tested as follows:

[0099] (1) Hardness: The test was conducted in accordance with GB / T 2411-2008 Plastics and hard rubber - Determination of indentation hardness (Shore hardness) using a hardness tester. The thickness of the sample was 6 mm.

[0100] (2) Cracking resistance: 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. The unit board is subjected to a thermal shock test under the test conditions of -40℃ / 120℃, 1 hour per round, for a total of 100 rounds.

[0101] (3) Evaluation of yellowing degree: The glue was dropped onto a glass slide, cured at 100°C for 0.5 h, and then baked at 200°C for 6 h. 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.

[0102] (4) Evaluation of low temperature warpage: Apply two-component epoxy adhesive 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, then take it out for observation and Figure 2 The -32°C low temperature warpage level classification chart shown grades the warpage level of the unit board, with 1 to 2 indicating relatively mild warpage and 4 to 5 indicating significantly worse warpage.

[0103] (5) Surface drying time: tested using the method in GB / T 13477.5-2002.

[0104] The test results are shown in Table 3.

[0105] Table 3

[0106]

[0107] The test results show that:

[0108] (1) It can be seen from Examples 1 to 21 that the present invention, by using a combination of component A and component B having specific components, makes the prepared two-component epoxy adhesive have 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.

[0109] (2) By comparing Example 1 with Examples 5 to 7, it can be seen that the combination of alicyclic amine curing agent and polyether amine 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.

[0110] (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 of the specific raw materials is conducive to improving the thermal shock resistance of the obtained two-component epoxy adhesive.

[0111] (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.

[0112] (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 can also adjust the curing rate and surface drying time, thereby improving its practicality.

[0113] (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 a polyetheramine curing agent is added to component B, the resulting two-component epoxy adhesive has poor resistance to low-temperature warping or resistance to thermal shock. Furthermore, by comparing Example 3 with Comparative Examples 3 and Comparative Examples 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.

[0114] (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 improving its low-temperature warpage.

[0115] The applicant declares that the above is only a specific implementation mode 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 thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope 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; The raw materials for preparing the A component include epoxy resin A, epoxy resin B, reactive diluent and anti-aging agent; The epoxy resin B is a flexible epoxy resin, and the flexible epoxy resin has 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 alicyclic amine curing agent, polyether amine curing agent and curing accelerator.

2. The two-component epoxy adhesive according to claim 1, characterized in that: The raw materials for preparing the A component include the following components in parts by weight: The raw materials for preparing the B component include the following components in parts by weight: Alicyclic amine curing agent 50-80 parts by weight Polyetheramine curing agent 9-30 parts by weight 2 to 10 parts by weight of curing accelerator.

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

4. The two-component epoxy adhesive according to claim 1 or 2, characterized in that: The epoxy equivalent of the epoxy resin B is 265 to 400 g / eq.

5. The two-component epoxy adhesive according to claim 1 or 2, characterized in that: The reactive diluent is an epoxy diluent; 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; The anti-aging agent includes an antioxidant and / or an ultraviolet absorber.

6. The two-component epoxy adhesive according to claim 1 or 2, characterized in that: The A component further comprises a defoaming agent and / or a coupling agent.

7. The two-component epoxy adhesive according to claim 1 or 2, characterized in that: The mass ratio of the alicyclic amine curing agent to the polyether amine curing agent is (2.5-7.4):1; The alicyclic amine curing agent has an amine value of 500-600 mgKOH / g and an active hydrogen equivalent of 50-70 g / eq.

8. The two-component epoxy adhesive according to claim 1 or 2, characterized in that: The mass ratio of component A to component B is (2-5):

1.

9. A method for preparing a two-component epoxy adhesive as claimed in any one of claims 1 to 8, 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 component A; (2) Preparation of component B: Mixing an alicyclic amine curing agent, a polyether amine curing agent and a curing accelerator to obtain the component B.

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

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