Camera AA processing glue and preparation method and application thereof

Abstract

The invention provides camera AA processing glue as well as a preparation method and application thereof. The camera AA process glue comprises the following raw materials: 6-10 parts of aliphatic epoxy resin, 4-6 parts of phenolic epoxy resin, 1-2 parts of hyperbranched epoxy resin, 4-6 parts of a flexibilizer, 0.1-1 part of a reactive diluent, 7-10 parts of an oxa compound, 0.5-1 part of a photoinitiator, 1-1.5 parts of a thermal initiator, 60-100 parts of a filler and 0.2-0.5 part of a coupling agent. According to the prepared AA adhesive, initial curing can be achieved within 2-5 S, the fixing effect is achieved, complete curing can be achieved within 10-30 min after post-curing is conducted at the temperature of 80-120 DEG C, the shear strength on anodic aluminum oxide after complete curing is conducted is larger than 30 MPa, and the shear bonding strength retention rate (%) after reliability is larger than 80%; secondly, the TG point height ranges from 130 DEG C to 156 DEG C, and the water absorption rate is 1t; 0.08%, and the curing shrinkage rate is lt; and 2%.

Description

Technical Field

[0001] This application relates to the technical field of adhesives, and particularly to a camera AA process adhesive and its preparation method and application. Background Art

[0002] In the process of camera module packaging, for zoom camera packaging, active alignment process technology is adopted to fix the lens and the base to prevent functional defects caused by focal length changes or bond the IR component and the VCM motor. Therefore, AA process adhesive is required.

[0003] In the camera module industry, continuous efforts are made to improve quality and performance. Especially in the fields of smart phones, vehicle systems, security equipment, etc., the demand for high-order camera modules such as triple cameras, quadruple cameras, optical image stabilization (OIS) and large aperture cameras is increasing rapidly. To achieve this goal, the role of AA process adhesive cannot be ignored. Traditional AA adhesives for consumer electronics such as mobile phones and computers are generally composed of acrylic systems, acrylic thiols, and hybrid systems of acrylic thiols and epoxy. Generally, the glass transition temperature (Tg) of AA adhesives is less than 40°C. However, in the requirements of national standards and actual use, this temperature is often exceeded. For example, in GB / T 36480-2018 "General Specification for Compact Embedded Cameras in Information Technology", it is stipulated in 6.7.1 Climatic Environmental Adaptability that the operating temperature of the camera is -10 - 55°C and the storage temperature is -20 - 60°C; in the automotive industry standard QC / T1128-2019 "Automotive Cameras", it is stipulated in 5.6.1 Temperature and Humidity Range that the operating temperature of the camera is -40 - 95°C. With the continuous improvement of the demand for automotive assisted autonomous driving and automotive active safety in modern society, the number of cameras on vehicles is also increasing. In summer, the temperature of vehicles in direct sunlight and without shading usually exceeds 40°C, so the operating temperature of in-vehicle cameras will also exceed 40°C. Above the glass transition temperature, the AA adhesive is in a viscous flow state, and its modulus and strength are very poor, which is likely to cause the movement of the camera, resulting in alignment failure and problems such as the camera not being able to be used normally.

[0004] The patent with the publication number CN 112795344 A discloses a dual-curing one-component epoxy resin adhesive and its preparation method. Its curing time under ultraviolet light irradiation is 10 - 35 s, and the thermal curing speed at 70 - 100°C is 20 - 80 min, which is difficult to meet the requirements of cameras for AA process adhesives. Therefore, it is imperative to improve the performance of AA process adhesives. Summary of the Invention

[0005] This application is made in view of the above problems, and its purpose is to provide a camera AA process adhesive and its preparation method and application.

[0006] Specifically, the first aspect of the present application provides a camera AA process glue, which includes the following raw materials in parts by weight: 6-10 parts of aliphatic epoxy resin, 4-6 parts of phenolic epoxy resin, 1-2 parts of hyperbranched epoxy resin, 4-6 parts of toughening agent, 0.1-1 part of reactive diluent, 7-10 parts of oxetane compound, 0.5-1 part of photoinitiator, 1-1.5 parts of thermal initiator, 60-100 parts of filler, and 0.2-0.5 part of coupling agent.

[0007] Further, the aliphatic epoxy resin is one or more of Celloxide 2021P, 5000, EPR-3150, S-28, DE1601, DE1701.

[0008] Further, the phenolic epoxy resin is one or two of EPalloy 8250 and ZLH-140H.

[0009] Further, the toughening agent is one or two of liquid rubber toughening agent CS205 and MX-154.

[0010] Further, the reactive diluent is one or more of 1,4-butanediol diglycidyl ether, phenyl glycidyl ether, neopentyl glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether.

[0011] Further, the oxetane compound includes one or more of 3,3'-(oxybis(methylene))bis(3-ethyl)oxetane, 3,3-bis(hydroxymethyl)-1-oxetane, methyl 4-methylbenzenesulfonate (oxetan-3-yl)methyl ester, methyl 4-methylbenzenesulfonate oxetan-2-yl ester, methyl oxetane-3-carboxylate, and 3-ethyl-3-oxetanemethanol.

[0012] Further, the photoinitiator includes one or more of diaryliodonium salts, triarylsulfonium salts, alkylsulfonium salts, iodonium hexafluorophosphate, and iodonium hexafluoroantimonate.

[0013] Further, the thermal initiator is one or more of cationic initiators CTI-100, ICAM-8416, DH080, DH090, and DH091.

[0014] Further, the filler includes one or more of nano-silica, alumina, mica, and white graphene. Among them, the nano-silica is 1-10 μm, the alumina is 1-10 μm, the particle size of mica is 1-20 μm, and the particle size of white graphene is 2-10 μm.

[0015] The second aspect of the present application provides a preparation method of a camera AA process glue, which includes the following steps:

[0016] Under yellow light conditions, the aliphatic epoxy resin, phenolic epoxy resin, toughening agent, active diluent, oxa compound, filler, and coupling agent are mixed in proportion and then stirred and dispersed.

[0017] A thermal initiator is added and dispersed evenly.

[0018] A photoinitiator is added and stirred evenly. During the reaction process, the temperature of the raw materials is controlled at <30°C, and finally vacuum degassing is carried out.

[0019] The third aspect of the present application provides an application of the camera AA process glue in a camera module.

[0020] The present invention has the following beneficial effects:

[0021] (1) In the camera AA process glue of the present invention, the aliphatic epoxy resin reacts with the photoinitiator, enabling the glue to achieve UV pre-curing with a curing time of 2 - 5S, ensuring that the product does not shift during movement and guaranteeing the accuracy of the product; the phenolic epoxy resin can increase the TG point of the product, ensuring the reliability of the product at high temperatures; meanwhile, the addition of the oxa compound can increase the photo-curing speed of the product, thereby improving production efficiency. In addition, by selecting a liquid rubber toughening agent in the present invention, the toughness and impact resistance of the AA process glue are improved without reducing the TG point; the introduction of hyperbranched epoxy resin further increases the TG point of the product; the selection of the filler can improve the moisture resistance of the product; the addition of the coupling agent effectively improves the interfacial bonding force between the inorganic filler and the organic resin, enhancing the mechanical properties and stability of the glue.

[0022] (2) For the AA glue prepared in the present invention, with an energy density of 150mW / cm 2 LED 365nm, preliminary curing can be achieved in 2 - 5S, reaching a fixed effect. Post-curing at 80 - 120°C for 10 - 30min can achieve complete curing. After complete curing, the shear strength on anodic alumina is >30MPa, and the retention rate (%) of the shear bond strength after reliability is >80%; secondly, the TG point is high, between 130 - 156°C, the water absorption rate <0.08%, and the curing shrinkage rate <2%, which can meet the requirements of the AA glue for cameras. Specific Embodiments

[0023] In order to make the purpose, technical solutions and advantages of the present application clearer, the following describes and explains the present application in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0024] Obviously, the following description is only some examples or embodiments of the present application. For those of ordinary skill in the art, without creative efforts, the present application can also be applied to other similar scenarios. In addition, it can also be understood that although the efforts made in this development process may be complex and lengthy, for those of ordinary skill in the art related to the content disclosed in the present application, some design, manufacturing, or production changes based on the technical content disclosed in the present application are only conventional technical means and should not be understood as the content disclosed in the present application being insufficient.

[0025] If there is no special indication, the "including" and "comprising" mentioned in the present application mean open-ended, and can also be closed-ended. For example, the "including" and "comprising" can mean that other components not listed can also be included or comprised, or only the listed components can be included or comprised.

[0026] If there is no special indication, in the present application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) while B is true (or exists); or both A and B are true (or exist).

[0027] An embodiment of the first aspect of the present application provides a glue for the AA process of a camera, including the following raw materials in parts by weight: 6 - 10 parts of aliphatic epoxy resin, 4 - 6 parts of phenolic epoxy resin, 1 - 2 parts of hyperbranched epoxy resin, 4 - 6 parts of toughening agent, 0.1 - 1 part of active diluent, 7 - 10 parts of oxa compound, 0.5 - 1 part of photoinitiator, 1 - 1.5 parts of thermal initiator, 60 - 100 parts of filler, and 0.2 - 0.5 part of coupling agent.

[0028] Preferably, the glue for the AA process of the camera includes the following raw materials in parts by weight: 6 - 8 parts of aliphatic epoxy resin, 4 - 5 parts of phenolic epoxy resin, 1.2 - 1.8 parts of hyperbranched epoxy resin, 4 - 5 parts of toughening agent, 0.3 - 0.6 part of active diluent, 8 - 9 parts of oxa compound, 0.5 - 0.8 part of photoinitiator, 1.2 - 1.3 parts of thermal initiator, 70 - 80 parts of filler, and 0.2 - 0.4 part of coupling agent.

[0029] More preferably, the glue for the AA process of the camera includes the following raw materials in parts by weight: 8 parts of aliphatic epoxy resin, 5 parts of phenolic epoxy resin, 1.5 parts of hyperbranched epoxy resin, 5 parts of toughening agent, 0.4 part of active diluent, 8 parts of oxa compound, 0.6 part of photoinitiator, 1.3 parts of thermal initiator, 80 parts of filler, and 0.3 part of coupling agent.

[0030] In the AA process glue of the present invention, the aliphatic epoxy resin reacts with the photoinitiator, enabling the glue to achieve UV pre-curing with a curing time of 2 - 5S, ensuring that the product does not shift during movement and guaranteeing the accuracy of the product; the phenolic epoxy resin can increase the TG point of the product, ensuring the reliability of the product at high temperatures; meanwhile, the addition of the oxacyclic compound can increase the photo-curing speed of the product, thereby improving production efficiency. In addition, by selecting a liquid rubber toughening agent, the toughness and impact resistance of the AA process glue are improved without reducing the TG point; the introduction of hyperbranched epoxy resin further increases the TG point of the product; the selection of fillers can improve the moisture resistance of the product; the addition of coupling agents effectively improves the interfacial bonding force between inorganic fillers and organic resins, enhancing the mechanical properties and stability of the glue.

[0031] In the embodiments of the present invention, the aliphatic epoxy resin is one or more of Celloxide 2021P, 5000, EPR-3150, S-28, DE1601, and DE1701.

[0032] The source of the aliphatic epoxy resin is:

[0033] The alicyclic epoxy resin Celloxide 2021P is from Guangzhou Taiji New Materials Co., Ltd.;

[0034] The alicyclic epoxy resin 5000 is from Guangzhou Situduanyuan Chemical Co., Ltd.;

[0035] The alicyclic epoxy resin EPR-3150 is from Xiamen Aikema Chemical Co., Ltd.;

[0036] The alicyclic epoxy resin S-28 is from SYNASIA;

[0037] The alicyclic epoxy resin DE1601 is from Yantai Donghua New Materials Co., Ltd.;

[0038] The alicyclic epoxy resin DE1701 is from Yantai Donghua New Materials Co., Ltd.

[0039] In the embodiments of the present invention, the phenolic epoxy resin is one or two of EPalloy 8250 and ZLH-140H.

[0040] The source of the phenolic epoxy resin is:

[0041] The phenolic epoxy resin EPalloy 8250 is from Shenzhen Jiadida New Materials Technology Co., Ltd.;

[0042] The phenolic epoxy resin ZLH-140H is from Hunan Sailwei New Materials Technology Co., Ltd.

[0043] In an embodiment of the present invention, the hyperbranched epoxy resin has the model number EV-2098 and is purchased from Shandong Litong New Material Technology Co., Ltd.

[0044] In an embodiment of the present invention, the toughening agent is one or both of the liquid rubber toughening agents CS205 and MX-154.

[0045] The source of the liquid rubber toughening agent is:

[0046] The liquid rubber toughening agent CS205 is from Hunan Sailwei New Material Technology Co., Ltd.;

[0047] The liquid rubber toughening agent RET-154 is from Shanghai Ruhong New Material Technology Co., Ltd.

[0048] In an embodiment of the present invention, the reactive diluent is one or a combination of more of 1,4-butanediol diglycidyl ether (BDDGE), phenyl glycidyl ether (PGE), neopentyl glycol diglycidyl ether (NPGDG), polypropylene glycol diglycidyl ether (PPG DG), 1,6-hexanediol diglycidyl ether (HDDGE). The role of the reactive diluent is to adjust the viscosity of the colloid for easy processing and application. At the same time, these reactive diluents can also participate in the subsequent curing reaction to form a crosslinked structure, thereby increasing the crosslink density and overall performance of the cured product. Among them, neopentyl glycol diglycidyl ether, as a reactive diluent, can reduce the viscosity of the epoxy resin system, improve its processability, and at the same time participate in the curing reaction of the epoxy resin to increase the crosslink density, thereby improving the performance of the cured product. The addition of polypropylene glycol diglycidyl ether can improve the wettability and adhesion of the colloid to the substrate, further improving the processability of the colloid and the mechanical properties of the cured product.

[0049] In an embodiment of the present invention, the oxacyclic compound includes one or more of 3,3'-(oxybis(methylene))bis(3-ethyl)oxetane, 3,3-bis(hydroxymethyl)-1-oxetane, methyl 4-methylbenzenesulfonate (oxetan-3-yl) ester, methyl 4-methylbenzenesulfonate oxetan-2-yl ester, methyl oxetane-3-carboxylate, and 3-ethyl-3-oxetanemethanol. The addition of the oxacyclic compound can increase the photocuring speed of the product, thereby improving the production efficiency.

[0050] In an embodiment of the present invention, the photoinitiator includes one or more of diaryliodonium salts, triarylsulfonium salts, alkylsulfonium salts, iodonium hexafluorophosphate, and iodonium hexafluoroantimonate. The photoinitiator can absorb light energy and generate free radicals or ions, thereby initiating a polymerization reaction, enabling the resin system to be rapidly cured in a short time. Selecting an appropriate type and dosage of the photoinitiator can ensure good curing effect and curing speed of the camera AA process glue in the UV pre-curing stage.

[0051] In an embodiment of the present invention, the thermal initiator is one or more of cationic initiators CTI-100, ICAM-8416, DH080, DH090, and DH091. The thermal initiator decomposes to generate free radicals or ions under heating conditions, further initiating the polymerization reaction of the resin system. The addition of the thermal initiator enables the camera AA process glue to obtain more complete curing in the subsequent thermal curing stage, improving the overall performance and stability of the cured product.

[0052] The source of the thermal initiator is:

[0053] Cationic initiator CTI-100, Shenzhen Youyang Technology Co., Ltd.;

[0054] Cationic initiator ICAM-8416, Anhui Kejing Materials Co., Ltd.;

[0055] Cationic initiators DH080, DH090, and DH091, Yantai Donghua New Materials Co., Ltd.

[0056] In an embodiment of the present invention, the filler includes one or more of nano-silica, alumina, mica, and white graphene. Among them, the particle size of nano-silica is 1-10 μm, the particle size of alumina is 1-10 μm, the particle size of mica is 1-20 μm, and the particle size of white graphene is 2-10 μm. The nano-silica is surface-treated nano-silica, which has a small particle size and a large specific surface area, and has good reinforcing, thickening, and thixotropic properties, and can significantly improve the mechanical properties and stability of the colloid. Alumina has high hardness and wear resistance, and can improve the scratch resistance of the colloid. Mica has good lamellar structure and heat insulation properties, which helps to improve the heat resistance and flame retardancy of the colloid. As a new two-dimensional material, white graphene has excellent electrical conductivity, thermal conductivity, and mechanical properties, and further improves the comprehensive performance of the colloid as a functional filler.

[0057] The coupling agent is one or more of silane coupling agents KH-550, KH-560, and KH-570. The role of the coupling agent is to enhance the interfacial bonding force between the inorganic filler and the organic resin. By reacting with the functional groups of the inorganic filler and the resin system at both ends respectively, the mechanical properties and stability of the glue are effectively improved.

[0058] An embodiment of the second aspect of the present application provides a method for preparing a camera AA process glue, including the following steps: Under yellow light conditions, the aliphatic epoxy resin, phenolic epoxy resin, toughening agent, active diluent, oxa compound, filler, and coupling agent are mixed in proportion and stirred and dispersed;

[0059] Add a thermal initiator and disperse evenly;

[0060] Add a photoinitiator and stir evenly. During the reaction process, control the raw material temperature < 30°C, and finally perform vacuum degassing.

[0061] In this method, a yellow light source is used in the preparation process of the AA process glue and it is carried out under yellow light conditions, which can effectively prevent unnecessary chemical reactions of the raw materials caused by ultraviolet rays or other high-energy radiations in the light, thereby ensuring the stability of each component of the glue and the performance of the final product. Controlling the raw material temperature < 30°C during the reaction process is mainly to avoid decomposition or premature reaction of the raw materials caused by high temperature, and to ensure that the prepared AA process glue has stable chemical and physical properties. In the vacuum degassing step, the bubbles in the mixed material are removed by means of vacuum pumping to avoid adverse effects of the bubbles on subsequent processing and product performance.

[0062] The third aspect of the present application provides an application of a camera AA process glue in a camera module.

[0063] Example 1

[0064] A camera AA process glue includes the following raw materials in parts by weight: 8 parts of aliphatic epoxy resin Celloxide 2021P, 6 parts of phenolic epoxy resin EPalloy 8250, 2 parts of hyperbranched epoxy resin, 5 parts of toughening agent MX-154, 0.1 part of reactive diluent BDDGE, 0.7 part of 3,3-bis(hydroxymethyl)-1-oxetane, 0.7 part of photoinitiator triarylsulfonium salt 6976, 1.2 parts of thermal initiator DH08, 60 parts of silica, 10 parts of mica, and 0.2 part of silane coupling agent KH560.

[0065] The preparation method of the camera AA process glue includes the following steps:

[0066] Under yellow light conditions, mix the aliphatic epoxy resin, phenolic epoxy resin, toughening agent, reactive diluent, oxetane compound, filler, and coupling agent in proportion, and stir and disperse;

[0067] Add a thermal initiator and disperse evenly;

[0068] Add a photoinitiator and stir evenly. During the reaction process, control the raw material temperature < 30°C, and finally perform vacuum degassing.

[0069] Example 2

[0070] This example is basically the same as Example 1, except that the photoinitiator triarylsulfonium salt 6976 is 0.8 part and the thermal initiator DH08 is 1 part.

[0071] Example 3

[0072] This example is basically the same as Example 1, except that the oxa compound is 7 parts of 3,3'-(oxybis(methylene))bis(3-ethyl)oxetane, 69920.7 parts of the photoinitiator triarylsulfonium salt, 15 parts of mica, and 0.4 part of KH560.

[0073] Example 4

[0074] This example is basically the same as Example 1, except that the amount of the aliphatic epoxy resin Celloxide 2021P is 10 parts, 4 parts of the phenolic epoxy resin EPalloy 8250, 6 parts of the toughening agent MX-154, 1 part of the diluent BDDGE, 8 parts of 3-ethyl-3-oxetanemethanol, 69920.8 parts of the photoinitiator triarylsulfonium salt, 0.8 part of the thermal initiator DH08, 60 parts of silica, and 10 parts of white graphene.

[0075] Example 5

[0076] This example is basically the same as Example 1, except that the aliphatic epoxy resin is 50006 parts, 6 parts of the toughening agent MX-154, 1 part of the diluent BDDGE, 9 parts of methyl 3-oxetanecarboxylate, 11 parts of the photoinitiator iodonium hexafluorophosphate salt PAG3020, 0.9 part of the thermal initiator DH09, the filler is 60 parts of silica, and 10 parts of white graphene.

[0077] Example 6

[0078] This example is basically the same as Example 5, except that the aliphatic epoxy resin DE160 is 18 parts, 4 parts of the phenolic epoxy resin ZLH-140H, 0.2 part of the diluent BDDGE, 8 parts of 2-methyloxetan-4-yl benzenesulfonate, and 21 parts of the photoinitiator iodonium hexafluoroantimonate salt PAG3110.

[0079] Comparative Example 1

[0080] This comparative example is basically the same as Example 1, except that the phenolic epoxy resin is not contained in the raw materials.

[0081] Comparative Example 2

[0082] This comparative example is basically the same as Example 1, except that the hyperbranched epoxy resin is not contained in the raw materials.

[0083] Comparative Example 3

[0084] This comparative example is basically the same as Example 1, except that the oxa compound is not contained in the raw materials.

[0085] Comparative Example 4

[0086] This comparative example is basically the same as Example 1, except that the raw materials do not contain a photoinitiator.

[0087] Comparative Example 5

[0088] This comparative example is basically the same as Example 1, except that the raw materials do not contain a thermal initiator.

[0089] Comparative Example 6

[0090] This comparative example is basically the same as Example 1, except that the amount of aliphatic epoxy resin is 20 parts.

[0091] Comparative Example 7

[0092] This comparative example is basically the same as Example 1, except that the amount of phenolic epoxy resin is 15 parts.

[0093] Comparative Example 8

[0094] This comparative example is basically the same as Example 1, except that the amount of filler is 10 parts.

[0095] Experimental case

[0096] The AA process adhesives prepared in the above Examples 1-6 and Comparative Examples 1-8 were subjected to performance testing, and the results are shown in Table 1, where:

[0097] The standard for viscosity testing is ASTM D4287, shear rate 5-S;

[0098] The standard for thixotropy index testing is GB / T 2794-2022 0.5 / 5-S;

[0099] Reference method for pot life: at room temperature, the time when the viscosity increases by 20%;

[0100] The standard for shear strength testing is GB / T GB / T 7124-2008; the bonding substrates are anodized aluminum, glass and PC sheets;

[0101] Glass transition temperature (Tg): measured using a TMA instrument, heating rate 10°C / min;

[0102] The standard for water absorption is DINENISO62-2008;

[0103] Curing shrinkage rate: (volume before curing - volume after curing) / volume before curing;

[0104] Reliability: double 85 / 1000H; thermal shock (-40 - 125°C) / 1000 cycle; high temperature 150°C / 1000H.

[0105] Table 1 Performance test results of the AA process glue in Examples 1-6 and Comparative Examples 1-8

[0106]

[0107]

[0108]

[0109] As can be seen from the above table, the AA process glue of the present invention exhibits excellent performance in terms of glass transition temperature, thermal conductivity, curing shrinkage rate, and reliability tests. The improvement of these properties benefits from the unique raw material formula and preparation process of the present invention, enabling the AA process glue to meet the application fields with high-precision and high-reliability requirements such as camera modules.

[0110] From Examples 1-6, it can be seen that the present invention uses aliphatic epoxy resin, phenolic epoxy resin, and hyperbranched epoxy resin as the resin system. By adding a photoinitiator and a thermal initiator, under UV curing conditions, with an energy density intensity of 150 mW / cm 2 LED 365 nm, initial curing can be achieved in 2-5 s to achieve a fixing effect, and complete curing can be achieved at 80-120 °C for 10-30 min. Compared with the prior art (CN 112795344 A, whose curing time under ultraviolet light irradiation is 10-35 s, and the thermal curing rate at 70-100 °C is 20-80 min), the curing time of the AA process glue of the present invention is shorter.

[0111] Moreover, from the test data in the above table, it can be seen that the bonding strength of the product of the present invention is high, reaching 12,840-26,780 cps; the shear strength of the AA process glue on anodized aluminum after complete curing > 30 MPa, and the retention rate (%) of the shear bond strength after reliability > 80%, indicating that the retention rate of the product after reliability is high; in addition, the present invention has a low water absorption rate of 0.07%-0.08%, and a low curing shrinkage of 1.6%-1.8%; at the same time, by adjusting the product formula and dosage, the present invention increases the TG, making the TG as high as 130 °C - 156 °C, which can meet the requirements of AA glue for cameras.

[0112] As can be seen from Examples 1-6 and Comparative Examples 1-2, when the raw materials for preparing the AA process adhesive do not contain phenolic epoxy resin or hyperbranched epoxy resin, the glass transition temperature decreases. The reason is that phenolic epoxy resin and hyperbranched epoxy resin play an important strengthening role in the resin system. Phenolic epoxy resin has a high crosslinking density and heat resistance, which can effectively improve the glass transition temperature and thermal stability of the AA process adhesive. Due to its unique molecular structure, hyperbranched epoxy resin can increase the molecular chain length and entanglement degree of the resin system, thereby improving the mechanical strength and weather resistance of the AA process adhesive. Therefore, when these two epoxy resins are not present in the raw materials, it will lead to a decrease in the glass transition temperature of the AA process adhesive, affecting its overall performance. This further verifies that the use of aliphatic epoxy resin, phenolic epoxy resin and hyperbranched epoxy resin as the resin system in the present invention has a synergistic effect on the performance of the product.

[0113] From the data comparison of Examples 1-6 and Comparative Examples 3-5, it can be seen that the types and amounts of oxa compounds, photoinitiators and thermal initiators also have a significant impact on the performance of the AA process adhesive. Among them, the oxa compound, as an active functional group in the resin system, can effectively promote the crosslinking reaction of the resin, improve the curing degree and crosslinking density of the AA process adhesive, thereby enhancing its heat resistance and mechanical strength. The photoinitiator plays a key role in the UV curing stage, and its type and amount directly affect the speed and effect of the initial curing. The thermal initiator plays a role in the subsequent thermal curing stage to ensure that the AA process adhesive can obtain more complete curing, further improving the overall performance and stability of the cured product. Therefore, when the raw materials do not contain oxa compounds, photoinitiators or thermal initiators, it will lead to a decrease in the curing degree of the AA process adhesive and insufficient crosslinking density. In Comparative Example 5, there is no thermal initiator and thermal curing cannot be carried out, thus affecting its key properties such as heat resistance, mechanical strength and reliability. This further proves the rationality of the raw material formula and preparation process in the present invention and the synergistic effect of each component in improving the performance of the AA process adhesive.

[0114] From the data comparison of Examples 1-6 and Comparative Examples 6-8, it can be seen that when the amount of aliphatic epoxy resin or phenolic epoxy resin exceeds the scope specified in this patent, the mechanical properties of the AA process glue are significantly reduced. In Comparative Example 6, the amount of aliphatic epoxy resin is increased to 20 parts. Although the glass transition temperature rises to 151°C, the shear strength (anodized aluminum) drops sharply to 16MPa, and the strength after high-temperature reliability is only 13MPa. This may be due to the excessive rigidity of the resin system, which leads to weakened interfacial adhesion. After increasing the phenolic epoxy resin to 15 parts in Comparative Example 7, the viscosity of the system increases sharply to 24560cps, and the shear strength drops by 30% on the glass substrate, confirming that excessive phenolic resin will destroy the internal stress balance of the resin system. When the filler amount is reduced to 10 parts in Comparative Example 8, the thixotropic index drops from 4.2 to 2.1, and the shear strength plummets from 36MPa to 4MPa after the double 85 test, indicating that insufficient filler content will weaken the rheological properties and wet heat stability of the material.

[0115] The experimental results show that the present invention achieves a dynamic balance between the flexibility and rigidity of the resin system by limiting the ratio range of 8-10 parts of aliphatic epoxy resin and 4-6 parts of phenolic epoxy resin, and optimizing the addition amount of filler ≥60 parts. When the ratio of aliphatic / phenolic epoxy resin is maintained within the above range, the thermal stability of the cross-linked network (Tg ≥ 130°C) can be guaranteed, and the shear strength can be maintained above 30MPa. In addition, the filler system forms a dense stacking effect through the gradient distribution of particle size, so that the water absorption rate is controlled below 0.08%, and the strength retention rate after reliability testing is increased to more than 85%.

[0116] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and the same effect as the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A glue for the AA process of a camera, characterized in that The following raw materials are included in parts by weight: 6-10 parts of aliphatic epoxy resin, 4-6 parts of phenolic epoxy resin, 1-2 parts of hyperbranched epoxy resin, 4-6 parts of toughening agent, 0.1-1 part of reactive diluent, 7-10 parts of oxetane compound, 0.5-1 part of photoinitiator, 1-1.5 parts of thermal initiator, 60-100 parts of filler, and 0.2-0.5 part of coupling agent.

2. The camera AA process glue according to claim 1, characterized in that, The aliphatic epoxy resin is one or more of Celloxide 2021P, 5000, EPR-3150, S-28, DE1601, and DE1701.

3. The camera AA process glue according to claim 1, characterized in that, The phenolic epoxy resin is one or both of EPalloy 8250 and ZLH-140H; and / or The toughening agent is one or both of liquid rubber toughening agent CS205 and MX-154.

4. The camera AA process glue according to claim 1, wherein The reactive diluent is one or more of 1,4-butanediol diglycidyl ether, phenyl glycidyl ether, neopentyl glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and 1,6-hexanediol diglycidyl ether.

5. The camera AA process glue according to claim 1, wherein, The oxetane compound includes one or more of 3,3'-(oxybis(methylene))bis(3-ethyl)oxetane, 3,3-bis(hydroxymethyl)-1-oxetane, methyl 4-methylbenzenesulfonate (oxetan-3-yl)methyl ester, methyl 4-methylbenzenesulfonate oxetan-2-ylmethyl ester, methyl oxetane-3-carboxylate, and 3-ethyl-3-oxetanemethanol.

6. The camera AA process glue according to claim 1, characterized in that, The photoinitiator includes one or more of diaryliodonium salts, triarylsulfonium salts, alkylsulfonium salts, iodonium hexafluorophosphate salts, and iodonium hexafluoroantimonate salts.

7. The camera AA process glue according to claim 1, characterized in that, The thermal initiator is one or more of cationic initiators CTI-100, ICAM-8416, DH080, DH090, and DH091.

8. The camera AA process glue according to claim 1, wherein, The filler includes one or more of nano-silica, alumina, mica, and white graphene.

9. A method for preparing the camera AA process glue according to any one of claims 1-8, characterized in that, The following steps are included: Under yellow light conditions, the aliphatic epoxy resin, phenolic epoxy resin, toughening agent, reactive diluent, oxetane compound, filler, and coupling agent are mixed in proportion and then stirred and dispersed. The thermal initiator is added and dispersed evenly. The photoinitiator is added and stirred evenly. During the reaction process, the temperature of the raw materials is controlled to be <30°C, and finally, vacuum degassing is performed.

10. Application of the camera AA process glue according to any one of claims 1-6 in a camera module.

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