Epoxy resin glue as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of fine chemical engineering, and discloses epoxy resin glue as well as a preparation method and application thereof. The epoxy resin glue comprises the following raw materials in parts by weight: 5-10 parts of bisphenol A type liquid epoxy resin, 3-25 parts of polyvinyl alcohol, 2-12 parts of a nonionic surfactant and 3-15 parts of a plasticizer. The hydroxyl value of the non-ionic surface active agent is 170 mgKOH / g to 230 mgKOH / g. The epoxy resin glue prepared by virtue of a synergistic effect of various components has excellent adhesive property, flexibility, mechanical property and stability, can be applied to manufacturing and / or assembling of a laminated inductor, and can effectively form tight interface bonding on the surface of an adhered object; the glue is suitable for stress change in the lamination manufacturing process, can still keep stable performance in a high-temperature severe environment, prolongs the service life of the inductor, guarantees the processing quality and subsequent use performance of the lamination inductor, and meets the requirement of the lamination manufacturing process for high-performance glue.

Description

Technical Field

[0001] The present invention relates to the technical field of fine chemical industry, and specifically discloses an epoxy resin glue, a preparation method thereof, and an application thereof. Background Art

[0002] A stacked inductor is a widely used microelectronic component. Its manufacturing process is complex and mainly includes the following steps: sanding, casting, film cutting, punching, printing, stacking, lamination, cutting, debinding, firing, chamfering, capping, end burning, deposition, appearance inspection, testing, taping, and packaging for shipment. Among them, stacking, as a key process for product forming, has a crucial impact on the performance of the stacked inductor. In the stacking process, in order to ensure good connection between layers and form a stable stacked structure, the glue plays a key connecting role, and its bonding performance directly affects the mechanical stability and electrical performance of the inductor. When the bonding performance of the glue is low, the inductor is extremely prone to deformation or damage when subjected to external forces; or when the connection between layers is poor, it will lead to an increase in the resistance and inductance loss of the inductor, thereby affecting its electrical performance.

[0003] In the prior art, commercial glues are usually used in the manufacture of stacked inductors. On the one hand, these glues are expensive, increasing the manufacturing cost of stacked inductors. On the other hand, different production environments and requirements for stacked inductors have different requirements for the performance of the glue, and commercial glues cannot fully meet the specific production needs of stacked inductors. At the same time, in the process of stacking manufacturing, commercial glues generally have the following problems: (1) The fluidity of the glue is insufficient, easily clogging the dispensing needle, affecting the normal production of products; (2) The glue cures too slowly and cannot form a uniform bonding layer during the dispensing process; (3) The glue is too hard after curing, easily restricting the flexibility or processability of the stacked inductor, resulting in cracking or damage of the product in subsequent processes; (4) When the glue is stored, it is easy to form a glue film on the container wall, affecting the subsequent use effect; (5) The bonding performance of the glue is unstable, easily affected by factors such as temperature, humidity, and storage time, resulting in a decrease in the qualified rate of stacked products. Therefore, there is an urgent need to develop a stacked inductor glue with excellent bonding performance, flexibility, and thermal stability, which can improve product quality and production efficiency to meet the demand for high-performance glue in the stacking manufacturing process. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an epoxy resin glue, a preparation method thereof, and an application thereof.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides an epoxy resin glue, and the epoxy resin glue comprises raw materials in the following parts by weight: 5-10 parts of bisphenol A liquid epoxy resin, 3-25 parts of polyvinyl alcohol, 2-12 parts of non-ionic surfactant, and 3-15 parts of plasticizer; the hydroxyl value of the non-ionic surfactant is 170 mgKOH / g - 230 mgKOH / g.

[0007] The epoxy resin glue obtained by compounding bisphenol A liquid epoxy resin, polyvinyl alcohol (PVA), non-ionic surfactant and plasticizer in the present invention has excellent adhesion performance, flexibility performance and stability performance. Among them, first of all, specific parts of bisphenol A liquid epoxy resin react with the hydroxyl groups in polyvinyl alcohol to form ether bonds, increasing the crosslinking points and improving the crosslinking density of the glue; this crosslinked structure not only enhances the cohesion of the glue, making it more durable, but also synergistically improves the overall adhesion strength and chemical resistance of the glue with other components. Secondly, the non-ionic surfactant with a specific hydroxyl value can synergistically increase the wettability and fluidity of the glue with other components, making the glue not easy to adhere, and can prevent the glue film formed on the container wall due to long-term storage, and the non-ionic surfactant can synergistically form an adsorption layer at the interface between the molecules of the PVA solution and the air, reducing the surface tension of the solution, and forming a moisture-retaining film on the surface of the glue to reduce water evaporation and maintain the wet state of the glue, further improving the wettability of the glue; it can also synergistically improve the solubility and dispersibility of the polymer in the PVA solution with other components, effectively preventing the aggregation or precipitation of polymer molecules in the solution and improving the stability of the glue; the non-ionic surfactant of the present invention can also form a protective layer around the PVA molecules, preventing the direct contact between PVA molecules, thereby effectively reducing the gelation and precipitation phenomena of the glue, and this protective layer also has antibacterial effects, helping to prevent the growth of microorganisms on the surface of the glue and extending the shelf life of the glue. At the same time, the plasticizer can make PVA flow under lower stress, and reduce the glass transition temperature (Tg) of PVA, and synergistically make the glue maintain sufficient flexibility even at lower temperatures with other components, effectively relieving the internal stress caused by temperature changes, significantly reducing the embrittlement and cracking phenomena of the material, and greatly improving the long-term mechanical stability of the glue; it can also act synergistically with other components to jointly adjust the viscoelasticity of the glue, enabling it to better adapt to the minor deformations of the adhered material during the long-term adhesion process, maintaining the close contact between the glue and the adhered material, and preventing the adhesion failure caused by the stress relaxation of the adhesive layer; and when subjected to external forces, it can better absorb and disperse stress, reducing the formation and expansion of cracks, thereby improving the toughness and durability of the glue.

[0008] As a preferred embodiment of the epoxy resin glue of the present invention, the epoxy resin glue comprises the following raw materials in parts by weight: 6-10 parts of bisphenol A liquid epoxy resin, 8-15 parts of polyvinyl alcohol, 3-7 parts of non-ionic surfactant, and 5-8 parts of plasticizer.

[0009] Preferably, the epoxy resin glue comprises the following raw materials in parts by weight: 7.5 parts of bisphenol A liquid epoxy resin, 7.5 parts of polyvinyl alcohol, 7.5 parts of non-ionic surfactant, and 7.5 parts of plasticizer.

[0010] As a preferred embodiment of the epoxy resin glue of the present invention, the mass ratio of the bisphenol A liquid epoxy resin to the polyvinyl alcohol is 1:(0.5-5).

[0011] Preferably, the mass ratio of the bisphenol A liquid epoxy resin to the polyvinyl alcohol is 1:(0.8-2).

[0012] More preferably, the mass ratio of the bisphenol A liquid epoxy resin to the polyvinyl alcohol is any one or the range value of both of 1:0.8, 1:1, 1:1.5, 1:2.

[0013] As a preferred embodiment of the epoxy resin glue of the present invention, the plasticizer is glycerol and / or diethylene glycol dibenzoate.

[0014] Preferably, the plasticizer is glycerol.

[0015] As a preferred embodiment of the epoxy resin glue of the present invention, the hydroxyl value of the non-ionic surfactant is any one or the range value of both of 170mgKOH / g, 180mgKOH / g, 190mgKOH / g, 200mgKOH / g, 210mgKOH / g, 220mgKOH / g, 230mgKOH / g.

[0016] The hydroxyl value of the non-ionic surfactant in the raw materials of the epoxy resin glue of the present invention is one of the key factors. When the hydroxyl value of the non-ionic surfactant is within the above suitable range, it can effectively disperse with other components, has good compatibility, ensures the uniform distribution of each component in the glue, and avoids the performance decline caused by uneven component distribution; and the hydroxyl functional group in the non-ionic surfactant can also effectively participate in the curing cross-linking reaction to form a stable cross-linked network structure. This cross-linked structure not only improves the strength and hardness of the glue, but also endows the glue with good stability and flexibility.

[0017] As a preferred embodiment of the epoxy resin glue of the present invention, the non-ionic surfactant is glycerol polyoxyethylene ether.

[0018] Second aspect, the present invention provides a method for preparing the epoxy resin glue, comprising the following steps:

[0019] (1) Mix the polyvinyl alcohol and the plasticizer to obtain mixture A;

[0020] (2) Add the non-ionic surfactant to mixture A to obtain mixture B;

[0021] (3) Add the bisphenol A liquid epoxy resin to mixture B to obtain the epoxy resin glue.

[0022] As a preferred embodiment of the preparation method of the present invention, in step (1), the mixing is carried out by ultrasonic means; the temperature of the ultrasonic is 80°C - 90°C, and the time is 1h - 3h.

[0023] The preparation method of the epoxy resin glue of the present invention has mild reaction conditions, simple operation steps, and is easy to scale up for industrial production.

[0024] Third aspect, the present invention provides the application of the epoxy resin glue in the manufacture and / or assembly of laminated inductors.

[0025] The epoxy resin glue of the present invention can be used in the manufacture and / or assembly of laminated inductors, and has broad application prospects and extremely important value. Its excellent bonding performance ensures a stable connection between the inductor element and the circuit board or other components, so that even under high vibration or impact conditions, the inductor element can remain stable and is not easily detached or loosened, thereby improving the reliability and durability of the laminated inductor. Secondly, the epoxy resin glue of the present invention has good fluidity, is not easily blocked during the use of the glue applicator needle, and the bonding layer formed after curing has high flexibility and can resist a certain degree of deformation and stress. This flexible property enables the laminated inductor to better adapt to and buffer when subjected to external forces, reducing the risk of damage caused by stress concentration. Moreover, the flexible bonding layer also helps to improve the seismic resistance and impact resistance of the laminated inductor and extend its service life. At the same time, during the manufacture and assembly of the laminated inductor, the excellent thermal stability of the epoxy resin glue of the present invention can ensure the normal operation of the inductor element in a harsh environment. In summary, due to its excellent bonding performance, flexible performance, mechanical properties and stable performance, the epoxy resin glue of the present invention has significant advantages in the manufacture and / or assembly of laminated inductors. These properties work together to improve the reliability, durability and service life of the laminated inductor, and have broad application prospects and extremely important value.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows: The epoxy resin glue prepared by the compounding of bisphenol A liquid epoxy resin, polyvinyl alcohol (PVA), non-ionic surfactant and plasticizer has excellent adhesion performance, flexible performance, mechanical performance and stability performance. At the same time, the epoxy resin glue of the present invention is used in the manufacture and / or assembly of multilayer inductors, and can effectively form a tight interfacial bond on the surface of the adherend, ensuring the processing quality and subsequent use performance of the multilayer inductor; Secondly, the epoxy resin glue of the present invention has good fluidity, is not easy to block the glue applicator needle during use, and is not easy to crack or damage after curing, and can resist a certain degree of deformation and stress, avoiding the bonding failure caused by stress concentration. Secondly, during the manufacture and assembly of multilayer inductors, the excellent thermal stability of the epoxy resin glue of the present invention still maintains good adhesion performance at high temperature environments (such as 80 °C), is not easy to fail, and thus ensures the normal operation of the inductance element in high temperature environments. In addition, the preparation method of the epoxy resin glue of the present invention does not require special processes and equipment, is easy to operate, can realize industrial production, and meets the requirements of large-scale processing. Detailed Embodiments

[0027] To better illustrate the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] The following is described in conjunction with specific embodiments to illustrate the actual effects of the present invention solution.

[0029] Unless otherwise specified, the test methods used in the examples are all conventional methods; the materials, reagents, equipment, etc. used, unless otherwise specified, can all be obtained from commercial channels.

[0030] Example 1: Preparation of Epoxy Resin Glue

[0031] The raw materials for preparing the multilayer inductor glue in this example include the following components in parts by weight: 85 parts of water, 7.5 parts of polyvinyl alcohol (PVA), 7.5 parts of glycerol, 7.5 parts of glycerol polyoxyethylene ether, and 7.5 parts of bisphenol A liquid epoxy resin.

[0032] (1) Mixing materials: Add water, polyvinyl alcohol (PVA) (purchased from: Xilong Science, white granular, purity above 99%, viscosity 50 mPa·s - 60 mPa·s, degree of hydrolysis above 97 (Model%), pH value 5 - 7) and glycerol into the container in sequence. Stir and shake well initially with a glass rod to ensure that all materials are fully mixed together.

[0033] (2) Ultrasonic treatment: Immerse the container filled with the mixture directly in the ultrasonic bath, turn on the ultrasonic wave and heat it to 80°C - 90°C, and carry out ultrasonic treatment for 0.5 hours. After the first ultrasonic treatment is completed, stir the mixture for 30 s to stir up the mixture at the bottom of the container to ensure that various components in the glue are evenly distributed. Conduct the second ultrasonic treatment for 0.5 hours. After the second ultrasonic treatment is completed, stir the mixture for 30 s again. Finally, conduct the third ultrasonic treatment for 0.5 - 1 hour, and at this time the mixture is completely dissolved.

[0034] (3) After the PVA is completely dissolved, add glycerol polyoxyethylene ether (purchased from: Hai'an Petrochemical Industry, model G18, hydroxyl value requirement 200 mgKOH / g, water content ≤ 1%, pH value requirement 5.0 - 7.0), stir for 1 minute, maintain the temperature at 80°C - 90°C during this period, continue ultrasonic treatment for 0.5 hours, and stir for 1 minute again after the ultrasonic treatment ends.

[0035] (4) Then add bisphenol A liquid epoxy resin (purchased from: Jinan Kayin Chemical Technology Co., Ltd., model D.E.R.332, epoxy equivalent 171 - 175, viscosity 4000 mPa·s - 6000 mPa·s @ 25°C), maintain ultrasonic heating at 80°C - 90°C for 0.5 hours, and continuously stir during this period to ensure that the bisphenol A liquid epoxy resin reacts and dissolves fully with the PVA solution.

[0036] (5) Cooling: Place the prepared glue at room temperature for cooling. During the cooling process, continuously stir to help the glue cool evenly and prevent skin formation on the surface. After it is completely cooled, filter it.

[0037] (6) Filtration: Pour the mixture into a fine mesh filter for filtration. Select a 100 - mesh screen for filtration to remove the undissolved PVA particles and other impurities. Collect the filtered glue in a dry and dust - free container for storage.

[0038] Example 2: Preparation of epoxy resin glue

[0039] The only difference between this example and Example 1 is that the raw materials of the epoxy resin glue in this example include the following components in weight fractions: 80 parts of water, 8 parts of polyvinyl alcohol (PVA), 5 parts of glycerol, 3 parts of glycerol polyoxyethylene ether, and 10 parts of bisphenol A liquid epoxy resin.

[0040] Example 3: Preparation of epoxy resin glue

[0041] The only difference between this example and Example 1 is that the raw materials of the epoxy resin glue in this example include the following components in weight fractions: 85 parts of water, 15 parts of polyvinyl alcohol (PVA), 8 parts of glycerol, 7 parts of glycerol polyoxyethylene ether, and 10 parts of bisphenol A liquid epoxy resin.

[0042] Example 4: Preparation of Epoxy Resin Adhesive

[0043] The only difference between this example and Example 1 is that the raw materials of the epoxy resin adhesive in this example include the following components in parts by weight: 70 parts of water, 3 parts of polyvinyl alcohol (PVA), 3 parts of glycerol, 2 parts of glycerol polyoxyethylene ether, and 6 parts of bisphenol A liquid epoxy resin.

[0044] Example 5: Preparation of Epoxy Resin Adhesive

[0045] The only difference between this example and Example 1 is that the raw materials of the epoxy resin adhesive in this example include the following components in parts by weight: 90 parts of water, 25 parts of polyvinyl alcohol (PVA), 15 parts of glycerol, 12 parts of glycerol polyoxyethylene ether, and 5 parts of bisphenol A liquid epoxy resin.

[0046] Example 6: Preparation of Epoxy Resin Adhesive

[0047] The only difference between this example and Example 1 is that the hydroxyl value of the glycerol polyoxyethylene ether in this example is 170 mgKOH / g.

[0048] Example 7: Preparation of Epoxy Resin Adhesive

[0049] The only difference between this example and Example 1 is that the hydroxyl value of the glycerol polyoxyethylene ether in this example is 190 mgKOH / g.

[0050] Example 8: Preparation of Epoxy Resin Adhesive

[0051] The only difference between this example and Example 1 is that the hydroxyl value of the glycerol polyoxyethylene ether in this example is 210 mgKOH / g.

[0052] Example 9: Preparation of Epoxy Resin Adhesive

[0053] The only difference between this example and Example 1 is that the hydroxyl value of the glycerol polyoxyethylene ether in this example is 230 mgKOH / g.

[0054] Comparative Example 1: Preparation of Epoxy Resin Adhesive

[0055] The only difference between this comparative example and Example 1 is that the raw materials of the epoxy resin adhesive in this comparative example do not include polyvinyl alcohol (PVA).

[0056] Comparative Example 2: Preparation of Epoxy Resin Adhesive

[0057] The only difference between this comparative example and Example 1 is that the raw materials of the epoxy resin adhesive in this comparative example do not include glycerol.

[0058] Comparative Example 3: Preparation of Epoxy Resin Adhesive

[0059] The only difference between this comparative example and Example 1 is that the raw materials of the epoxy resin adhesive in this comparative example do not include glycerol polyoxyethylene ether.

[0060] Comparative Example 4: Preparation of Epoxy Resin Adhesive

[0061] The only difference between this comparative example and Example 1 is that bisphenol A liquid epoxy resin is replaced by bisphenol F liquid epoxy resin.

[0062] Comparative Example 5: Preparation of Epoxy Resin Adhesive

[0063] The only difference between this comparative example and Example 1 is that the raw materials of the epoxy resin adhesive in this comparative example include the following components in parts by weight: 85 parts of water, 2 parts of polyvinyl alcohol (PVA), 7.5 parts of glycerol, 7.5 parts of glycerol polyoxyethylene ether, and 20 parts of bisphenol A liquid epoxy resin.

[0064] Comparative Example 6: Preparation of Epoxy Resin Adhesive

[0065] The only difference between this comparative example and Example 1 is that the raw materials of the epoxy resin adhesive in this comparative example include the following components in parts by weight: 85 parts of water, 16 parts of polyvinyl alcohol (PVA), 7.5 parts of glycerol, 7.5 parts of glycerol polyoxyethylene ether, and 2 parts of bisphenol A liquid epoxy resin.

[0066] Comparative Example 7: Preparation of Epoxy Resin Adhesive

[0067] The only difference between this comparative example and Example 1 is that the hydroxyl value of the glycerol polyoxyethylene ether in the epoxy resin adhesive of this example is 150 mgKOH / g.

[0068] Comparative Example 8: Preparation of Epoxy Resin Adhesive

[0069] The only difference between this comparative example and Example 1 is that the hydroxyl value of the glycerol polyoxyethylene ether in the epoxy resin adhesive of this example is 300 mgKOH / g.

[0070] Test Example: Performance Test of Epoxy Resin Adhesive

[0071] (1) Bonding Performance Test

[0072] Use a rotational viscometer (purchased from: Yongda (Shenzhen) Technology Co., Ltd.) to measure the viscosities of the adhesives in the examples and comparative examples.

[0073] Test method: Rotational viscometry.

[0074] Test standard: ASTM D2196 "Test Method for Viscosity of Non-Newtonian Fluids".

[0075] Testing instrument: Brookfield DV2T rotational viscometer (adapter SC4-21).

[0076] Testing conditions: Temperature: 25 ± 0.5 °C (controlled by constant temperature water bath); Shear rate: 10 rpm; Sample volume: 50 mL (test after standing to defoam without bubbles).

[0077] Operation steps: (i) Pour the glue into the viscometer adapter and keep it at a constant temperature for 10 minutes; (ii) Start the viscometer and record the reading after it stabilizes; (iii) Repeat 3 times and take the average value.

[0078] (2) Curing time test

[0079] Testing method: Visual observation method.

[0080] Testing standard: ISO 4586-2 "Determination of Curing Time of Adhesives".

[0081] Testing instruments: Constant temperature and humidity chamber (25 °C / 50% RH), stopwatch.

[0082] Testing conditions: Adhesive layer thickness: 0.1 mm (on the laminated inductor specimen); Judgment of curing end point: The surface of the adhesive layer has no stickiness and can bear a 5 g weight without deformation.

[0083] Operation steps: (i) Start timing immediately after applying the glue; (ii) Gently touch the surface with a probe every 10 seconds and record the complete curing time.

[0084] (3) Flexibility performance test

[0085] The flexibility performance is evaluated by measuring the hardness (Shore A) of the glue in the examples and comparative examples.

[0086] Testing method: Indentation method with Shore A durometer.

[0087] Testing standard: ASTM D2240 "Test Method for Rubber Hardness".

[0088] Testing instrument: Shore A durometer (accuracy ±1 HA) (purchased from Shanghai Yifan Industrial Equipment Co., Ltd.).

[0089] Testing conditions: Curing time: 24 hours (25 °C), completely cured;

[0090] Testing points: 3 points evenly distributed on the surface of the specimen.

[0091] Operation steps: (i) Vertically press the durometer into the surface of the adhesive layer; (ii) Read the value after stabilizing for 5 seconds; (iii) Take the average value of 3 measurements.

[0092] (4) Stability performance test

[0093] Measure the initial viscosities of the glues of the examples and comparative examples using a rotational viscometer. Then place the glue samples in an incubator (80 °C) and let them stand for one week. After one week, take out the samples, cool them to room temperature, and measure the viscosities of each glue sample again using the viscometer. Compare the initial and final viscosities and calculate the viscosity change rate to evaluate the stability of the glue at high temperatures.

[0094] Test method: Comparison of viscosities after high-temperature aging.

[0095] Test standard: ISO 2555 "Determination of Melt Flow Rate of Plastics".

[0096] Test instruments: Incubator (80 °C), rotational viscometer.

[0097] Test conditions: Aging time: 168 hours; Sample volume: 50 mL (stored in a sealed container).

[0098] Operating steps: (i) Initial viscosity test (25 °C); (ii) After aging, cool to 25 °C and repeat the viscosity test; (iii) Calculate the change rate.

[0099] Viscosity change rate (%) = (ηinitial - ηaging) / ηinitial × 100%.

[0100] (5) Tensile strength and elongation at break test

[0101] Test method: Tensile test of dumbbell-shaped specimens.

[0102] Test standard: ASTM D638 "Tensile Properties of Plastics".

[0103] Test instrument: Instron 5967 universal material testing machine. (Purchased from Instron)

[0104] Test conditions: Specimen size: ASTM D638 Type V dumbbell specimen; Tensile rate: 5 mm / min; Sample volume: 5 groups of specimens.

[0105] Operating steps: (i) Prepare a 2-mm-thick cured glue film and cut it into standard dumbbell shapes; (ii) Clamp the specimens for tensile testing and record the stress-strain curve; (iii) Calculate the tensile strength (MPa) and elongation at break (%).

[0106] (6) Chemical resistance test

[0107] Test method: Change in properties after immersion in a corrosive medium.

[0108] Test standard: ASTM D543 "Chemical Resistance of Plastics".

[0109] Testing instruments: Constant temperature bath, electronic balance (accuracy 0.1 mg).

[0110] Testing conditions: Corrosion medium: 5% NaCl solution; Immersion time: 30 days; Temperature: 25 ± 1 °C.

[0111] Operating steps: (i) Weigh the initial mass (m1) of the cured adhesive film; (ii) Take it out after immersion, wash with deionized water and dry; (iii) Weigh the final mass (m2) and calculate the mass change rate;

[0112] Calculate the mass change rate (%) = (m2 - m1) / m1 × 100%;

[0113] (iv) Observe whether the surface blisters or cracks.

[0114] Table 1 Test results of the performance of the epoxy resin glue in the test examples

[0115]

[0116]

[0117] It can be seen from the data in Table 1 that: First of all, the epoxy resin glue prepared by the components with specific contents in the embodiments of the present invention has excellent bonding performance, and its viscosity is stable between 3800 mPa·s - 5200 mPa·s, which means that it has good fluidity and controllability during coating, and at the same time can form a firm and lasting bond with the surface of the adherend after curing; Secondly, its curing time is 38 s - 55 s, which means that the epoxy resin glue in the embodiments of the present invention can be quickly cured to form a uniform bonding layer during the dispensing process, which is beneficial to shortening the production cycle and improving production efficiency; And it has excellent flexibility, and its hardness is 60 Shore A - 75 Shore A, which means that the epoxy resin glue in the embodiments of the present invention has good fluidity. On the one hand, it is not easy to block the dispensing needle during use, and on the other hand, the glue is not easy to crack or damage after curing, and can effectively disperse external stress to avoid bonding failure caused by stress concentration; At the same time, through the tests of tensile strength and elongation at break, the epoxy resin glue in the embodiments of the present invention shows excellent mechanical properties after curing, and its tensile strength is 10.2 MPa - 14.0 MPa, which proves that it can form a tight interfacial bond on the surface of the adherend and effectively resist external forces such as peeling, shearing and impact; In addition, through the test of stability performance, the epoxy resin glue in the embodiments of the present invention still maintains good bonding performance in a high-temperature environment (such as 80 °C), which means that even when encountering high-temperature conditions in the working or storage environment, the epoxy resin glue in the embodiments of the present invention can maintain its bonding effect and is not easy to fail.

[0118] Compared with Example 1, in Comparative Examples 1-6, the epoxy resin glue does not adopt the compounding of bisphenol A liquid epoxy resin, polyvinyl alcohol, non-ionic surfactant and plasticizer, or the mass ratio of bisphenol A liquid epoxy resin and polyvinyl alcohol is not 1:(0.5-5), resulting in a significant decline in the overall performance of the epoxy resin glue in Comparative Examples 1-6; in Comparative Example 7, the hydroxyl value of the surfactant is too small, reducing its compatibility with the epoxy resin, leading to phase separation or uneven dispersion, and the insufficient number of hydroxyl groups makes it difficult for the surfactant to effectively participate in the curing reaction, resulting in too long curing time of the epoxy resin glue and a decline in both mechanical properties and stability; in Comparative Example 8, the hydroxyl value of the non-ionic surfactant is too large, resulting in too fast curing reaction or excessive cross-linking, making the curing time of the prepared epoxy resin glue too long, the cured adhesive layer too hard and the stability poor;

[0119] Thus, it can be seen that the epoxy resin glue made of the components with specific contents of the present invention has excellent bonding performance, flexibility, mechanical properties and stability. It can effectively form a tight interfacial bond on the surface of the adherend, ensuring the processing quality and subsequent use performance of the multilayer inductor to meet the requirements of the multilayer manufacturing process for high-performance glue.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An epoxy resin glue, characterized in that, The epoxy resin glue comprises the following raw materials in parts by weight: 5-10 parts of bisphenol A liquid epoxy resin, 3-25 parts of polyvinyl alcohol, 2-12 parts of nonionic surfactant, and 3-15 parts of plasticizer; the hydroxyl value of the nonionic surfactant is 170 mgKOH / g - 230 mgKOH / g.

2. The epoxy resin glue according to claim 1, characterized in that, The epoxy resin glue comprises the following raw materials in parts by weight: 6-10 parts of bisphenol A liquid epoxy resin, 8-15 parts of polyvinyl alcohol, 3-7 parts of nonionic surfactant, and 5-8 parts of plasticizer.

3. The epoxy resin glue according to claim 1, characterized in that, The mass ratio of the bisphenol A liquid epoxy resin to the polyvinyl alcohol is 1:(0.5 - 5).

4. The epoxy resin glue according to claim 3, characterized in that, The mass ratio of the bisphenol A liquid epoxy resin to the polyvinyl alcohol is 1:(0.8 - 1.5).

5. The epoxy resin glue according to claim 1, characterized in that, The plasticizer is glycerol and / or diethylene glycol dibenzoate.

6. The epoxy resin glue according to claim 1, characterized in that, The hydroxyl value of the nonionic surfactant is 200 mgKOH / g.

7. The epoxy resin glue according to claim 1, characterized in that, The nonionic surfactant is glycerol polyoxyethylene ether.

8. The preparation method of the epoxy resin glue according to any one of claims 1-7, characterized in that, Comprising the following steps: (1) Mix the polyvinyl alcohol and the plasticizer to obtain mixture A; (2) Add the nonionic surfactant to mixture A to obtain mixture B; (3) Add the bisphenol A liquid epoxy resin to mixture B to obtain the epoxy resin glue.

9. The preparation method according to claim 8, characterized in that, In step (1), the mixing is carried out by ultrasonic means; the temperature of the ultrasonic wave is 80°C - 90°C, and the time is 1 h - 3 h.

10. Use of the epoxy resin glue according to any one of claims 1 - 7 in the manufacture and / or assembly of laminated inductors.

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