Vehicle-mounted encapsulating adhesive with good moisture and heat resistance and preparation method thereof

Abstract

The present application relates to a kind of vehicle-mounted encapsulating glue with good wet heat resistance, which is composed of the following raw materials: 10-25 parts of self-synthesized liquid crystal epoxy resin, 15-35 parts of p-o-methylphenol formaldehyde epoxy resin, 10-15 parts of polyether modified epoxy resin, 32-37 parts of self-synthesized linear phenol formaldehyde resin, 5-7 parts of microcapsule type imidazole compound and 3-4 parts of fumed silica. The encapsulating glue prepared by the present application has the advantages of good single-component operability, good bonding performance, good flexibility, good wet heat resistance, good high and low temperature resistance and good electrical insulation performance, and is suitable for sealing and protecting circuit boards of various types of vehicle-mounted modules.

Description

Technical Field

[0001] This invention relates to a vehicle sealing adhesive with good resistance to moisture and heat, belonging to the field of adhesives. Background Technology

[0002] With the advent of the era of intelligence, digitalization, and diversification, the automotive industry is also undergoing a new upgrade in terms of technology, consumption, and experience. New energy vehicles, featuring intelligent cockpits, intelligent driving, and intelligent cloud computing, have become the main direction for the future development of the automotive industry. As pure electric vehicles, new energy vehicles require electronic control systems for vehicle control, motor control, and charging control. Electronic control systems play a crucial role in the development of new energy vehicles. Encapsulating adhesives provide structural bonding and sealing protection for integrated electronic components within the electronic control systems of new energy vehicles. These adhesives offer good process operability, high bonding performance, and high reliability, effectively improving the functionality, stability, and safety of the electronic control systems.

[0003] Most encapsulating adhesives have problems such as poor adhesion, poor resistance to damp heat, poor resistance to high and low temperatures, and poor insulation performance, which cannot meet the various performance requirements brought about by the current development of automotive electronic control system technology towards automation, intelligence and diversification. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an encapsulating adhesive with good resistance to damp heat. The encapsulating adhesive prepared by this invention has the advantages of good single-component workability, good adhesion, good flexibility, good resistance to damp heat, good resistance to high and low temperatures, and good electrical insulation.

[0005] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A method for preparing an automotive sealing adhesive with good resistance to moisture and heat:

[0006] a. By mass parts: 13-14 parts of 4,4'-bis(2-hydroxyethoxy)biphenyl and 18-19 parts of N,N-dimethylformamide were added to a reaction vessel and stirred at 10 RPM for 1-2 hours until completely dissolved; 17-19 parts of 40% sodium hydroxide aqueous solution were added, and the mixture was heated to 85-95℃ and stirred under vacuum at 10 RPM for 1-2 hours; 0.2-0.3 parts of benzyltriethylammonium chloride were added, and 49-51 parts of epichlorohydrin were added dropwise within 30 minutes; the mixture was heated to 110-120℃ and stirred under reflux at 20 RPM for 4-6 hours; the mixture was then cooled to room temperature; the mixture was washed 2-3 times with a 3:1 mixture of anhydrous ethanol and acetone, and dried at 60℃ for 1-2 hours to obtain the self-synthesized liquid crystal epoxy resin;

[0007] b. By mass parts: 10-15 parts of resorcinol, 45-55 parts of 2,6-dihydroxymethyl-p-cresol, and 35-40 parts of 40% formaldehyde aqueous solution are sequentially added to a reaction vessel. Under nitrogen protection, the stirring speed is set to 10 RPM and stirred for 0.5-1 h until the mixture is homogeneous. 0.3-0.5 parts of oxalic acid are added, and the mixture is heated to 55-65℃. Under nitrogen protection, the stirring speed is set to 20 RPM and stirred for 1-2 h. The mixture is then heated to 90-95℃. The mixture is washed 3-4 times with deionized water, heated to 110-120℃, and under vacuum, the stirring speed is set to 20 RPM and stirred for 2-3 h to obtain the self-synthesized linear phenolic resin.

[0008] c. By mass parts: 10-25 parts of self-synthesized liquid crystal epoxy resin, 15-35 parts of p-cresol epoxy resin, and 32-37 parts of self-synthesized linear phenolic resin are sequentially added to a stirred tank, heated to 45-55℃, and stirred at 30 RPM for 2-3 hours; cooled to room temperature, 10-15 parts of polyether-modified epoxy resin and 3-4 parts of fumed silica are sequentially added to the stirred tank, and stirred at 30 RPM under vacuum for 1-2 hours; 5-7 parts of microencapsulated imidazole compound are added to the stirred tank, and stirred at 20 RPM under vacuum for 2-3 hours to obtain the encapsulating adhesive.

[0009] The beneficial effects of this invention are as follows: The encapsulating adhesive of this invention has the characteristics of good single-component operability and good electrical insulation performance, effectively meeting the design and process diversity of automotive module circuit board products. It has good adhesion performance and is suitable for structural bonding of various circuit board materials and related module electronic components, exhibiting high applicability. It also has good flexibility, good resistance to damp heat, and good resistance to high and low temperatures, effectively ensuring the functionality and reliability requirements of automotive module circuit boards.

[0010] Based on the above technical solution, the present invention has also made the following improvements.

[0011] Furthermore, the synthesis mechanism of the self-synthesized liquid crystal epoxy resin is that the hydroxyl groups in 4,4'-bis(2-hydroxyethoxy)biphenyl and the epoxy groups in epichlorohydrin synthesize a liquid crystal epoxy compound through esterification and epoxidation reactions, and the specific reaction formula is as follows:

[0012] The beneficial effects of adopting the above-mentioned further scheme are that the self-synthesized liquid crystal epoxy resin combines the advantages of liquid crystal order and benzene ring network crosslinking, and has good heat resistance, water resistance and impact resistance. In addition, the liquid crystal epoxy resin also has advantages such as good electrical resistance in the orientation direction, reduced free volume to improve flexibility and adhesion.

[0013] Furthermore, the p-cresol epoxy resin is SRN-1730 produced by Nanjing Yuelai New Material Technology Co., Ltd.

[0014] The beneficial effect of adopting the above-mentioned further solution is that the p-cresol epoxy resin has excellent bonding strength and heat resistance, as well as excellent electrical insulation properties.

[0015] Furthermore, the synthesis mechanism of the self-synthesized linear phenolic resin is that the phenolic groups in resorcinol and 2,6-bis(hydroxymethyl)-p-cresol and the aldehyde groups in formaldehyde undergo an oxidation reaction under acidic conditions to synthesize a high-ortho-linear phenolic resin, the specific reaction formula of which is as follows:

[0016] The beneficial effects of adopting the above-mentioned further scheme are that the structure in which the ortho-methyl and para-methyl groups of the benzene ring are linked in the self-synthesized linear phenolic resin significantly improves the flexibility and regularity of the polymer molecular chain, and has good heat resistance, water resistance and adhesion properties. At the same time, the phenolic hydroxyl groups on the molecular structure can be cured and crosslinked with epoxy groups under the promotion of tertiary amines, and have good reactivity and stability.

[0017] Furthermore, the polyether-modified epoxy resin is YLSE-2000 produced by Nanjing Yuelai New Material Technology Co., Ltd., and its specific structural formula is as follows:

[0018] The beneficial effect of adopting the above-mentioned further solution is that the polyether-modified epoxy resin introduces ether bonds into the epoxy resin molecular chain, giving it advantages such as good flexibility, good adhesion, and good electrical insulation.

[0019] Furthermore, the microencapsulated imidazole compound is HX-3721 manufactured by Asahi Kasei Corporation of Japan.

[0020] The beneficial effects of adopting the above-mentioned further scheme are that the microencapsulated imidazole compound uses microencapsulation technology, uses liquid epoxy resin to encapsulate the imidazole component, and releases it when heated; it has the advantages of good stability, high reactivity, and rapid curing at low temperature. Detailed Implementation

[0021] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention. Example 1

[0022] a. By mass fraction: 130g of 4,4'-bis(2-hydroxyethoxy)biphenyl and 190g of N,N-dimethylformamide were added to a reaction vessel and stirred at 10 RPM for 1 hour until completely dissolved; 170g of 40% sodium hydroxide aqueous solution was added, heated to 85℃, and stirred under vacuum at 10 RPM for 2 hours; 2g of benzyltriethylammonium chloride was added, and 510g of epichlorohydrin was added dropwise, completing the process within 30 minutes; the temperature was raised to 120℃, and the stirring was refluxed at 20 RPM for 6 hours; the mixture was then cooled to room temperature; the resin was washed twice with a 3:1 mixture of anhydrous ethanol and acetone, and dried at 60℃ for 2 hours to obtain the self-synthesized liquid crystal epoxy resin.

[0023] b. By mass parts: 100g of resorcinol, 550g of 2,6-bis(hydroxymethyl)-p-cresol, and 350g of 40% formaldehyde aqueous solution were sequentially added to a reaction vessel. Under nitrogen protection, the mixture was stirred at 10 RPM for 1 hour until homogeneous. 3g of oxalic acid was added, and the mixture was heated to 55℃. Under nitrogen protection, the mixture was stirred at 20 RPM for 2 hours and then heated to 95℃. The mixture was washed three times with deionized water, heated to 120℃, and stirred at 20 RPM under vacuum for 3 hours to obtain the self-synthesized linear phenolic resin.

[0024] c. By mass parts: 200g of self-synthesized liquid crystal epoxy resin, 250g of p-cresol epoxy resin SRN-1730, and 350g of self-synthesized linear phenolic resin were sequentially added to a stirred tank, heated to 50℃, and stirred at 30 RPM for 2 hours; after cooling to room temperature, 100g of polyether-modified epoxy resin YLSE-2000 and 40g of fumed silica were sequentially added to a stirred tank, and stirred at 30 RPM under vacuum for 2 hours; 60g of microencapsulated imidazole compound HX-3721 was added to a stirred tank, and stirred at 20 RPM under vacuum for 3 hours to obtain the encapsulating adhesive. Example 2

[0025] a. By mass parts: 140g of 4,4'-bis(2-hydroxyethoxy)biphenyl and 180g of N,N-dimethylformamide were added to a reaction vessel and stirred at 10 RPM for 1 hour until completely dissolved; 190g of 40% sodium hydroxide aqueous solution was added, heated to 95℃, and stirred under vacuum at 10 RPM for 0.5 hours; 3g of benzyltriethylammonium chloride was added, and 490g of epichlorohydrin was added dropwise, completing the process within 30 minutes; the temperature was raised to 120℃, and the stirring was carried out under reflux at 20 RPM for 4 hours; the mixture was then cooled to room temperature; the mixture was washed twice with a 3:1 mixture of anhydrous ethanol and acetone, and dried at 60℃ for 1 hour to obtain the self-synthesized liquid crystal epoxy resin;

[0026] b. By mass parts: 150g of resorcinol, 450g of 2,6-bis(hydroxymethyl)-p-cresol, and 400g of 40% formaldehyde aqueous solution were sequentially added to a reaction vessel. Under nitrogen protection, the mixture was stirred at 10 RPM for 1 hour until homogeneous. 5g of oxalic acid was added, and the mixture was heated to 65℃. Under nitrogen protection, the mixture was stirred at 20 RPM for 1 hour and then heated to 90℃. The mixture was washed four times with deionized water, heated to 110℃, and stirred at 20 RPM under vacuum for 2 hours to obtain the self-synthesized linear phenolic resin.

[0027] c. By mass parts: 100g of self-synthesized liquid crystal epoxy resin, 350g of p-cresol epoxy resin SRN-1730, and 320g of self-synthesized linear phenolic resin were sequentially added to a stirred tank, heated to 50℃, and stirred for 3h at a speed of 30 RPM. After cooling to room temperature, 150g of polyether-modified epoxy resin YLSE-2000 and 30g of fumed silica were sequentially added to a stirred tank, and stirred for 1h at a speed of 30 RPM under vacuum. 50g of microencapsulated imidazole compound HX-3721 was added to a stirred tank, and stirred for 2h at a speed of 20 RPM under vacuum to obtain the encapsulating adhesive. Example 3

[0028] a. By mass parts: 130g of 4,4'-bis(2-hydroxyethoxy)biphenyl and 180g of N,N-dimethylformamide were added to a reaction vessel and stirred at 10 RPM for 1 hour until completely dissolved; 190g of 40% sodium hydroxide aqueous solution was added, heated to 85℃, and stirred under vacuum at 10 RPM for 1 hour; 3g of benzyltriethylammonium chloride was added, and 500g of epichlorohydrin was added dropwise, completing the process within 30 minutes; the temperature was raised to 120℃, and the stirring was carried out under reflux at 20 RPM for 5 hours; the mixture was then cooled to room temperature; the mixture was washed three times with a 3:1 mixture of anhydrous ethanol and acetone, and dried at 60℃ for 2 hours to obtain the self-synthesized liquid crystal epoxy resin.

[0029] b. By mass parts: 120g of resorcinol, 530g of 2,6-bis(hydroxymethyl)-p-cresol, and 350g of 40% formaldehyde aqueous solution were sequentially added to a reaction vessel. Under nitrogen protection, the mixture was stirred at 10 RPM for 1 hour until homogeneous. 3g of oxalic acid was added, and the mixture was heated to 65℃. Under nitrogen protection, the mixture was stirred at 20 RPM for 2 hours and then heated to 90℃. The mixture was washed four times with deionized water, heated to 120℃, and stirred at 20 RPM under vacuum for 3 hours to obtain the self-synthesized linear phenolic resin.

[0030] c. By mass parts: 250g of self-synthesized liquid crystal epoxy resin, 150g of p-cresol epoxy resin SRN-1730, and 370g of self-synthesized linear phenolic resin were sequentially added to a stirred tank, heated to 45℃, and stirred at 30 RPM for 2 hours; after cooling to room temperature, 120g of polyether-modified epoxy resin YLSE-2000 and 40g of fumed silica were sequentially added to a stirred tank, and stirred at 30 RPM under vacuum for 1 hour; 70g of microencapsulated imidazole compound HX-3721 was added to a stirred tank, and stirred at 20 RPM under vacuum for 3 hours to obtain the encapsulating adhesive.

[0031] Comparative Example 1

[0032] a. By mass parts: 100g of resorcinol, 550g of 2,6-bis(hydroxymethyl)-p-cresol, and 350g of 40% formaldehyde aqueous solution were sequentially added to a reaction vessel. Under nitrogen protection, the mixture was stirred at 10 RPM for 1 hour until homogeneous. 3g of oxalic acid was added, and the mixture was heated to 55℃. Under nitrogen protection, the mixture was stirred at 20 RPM for 2 hours and then heated to 95℃. The mixture was washed three times with deionized water, heated to 120℃, and stirred at 20 RPM under vacuum for 3 hours to obtain a self-synthesized linear phenolic resin.

[0033] b. By mass parts: 200g of bisphenol A type solid epoxy resin, 250g of p-o-cresol epoxy resin SRN-1730, and 350g of self-synthesized linear phenolic resin were sequentially added to a stirred tank, heated to 50℃, and stirred at 30 RPM for 2 hours; after cooling to room temperature, 100g of polyether modified epoxy resin YLSE-2000 and 40g of fumed silica were sequentially added to the stirred tank, and stirred at 30 RPM under vacuum for 2 hours; 60g of microencapsulated imidazole compound HX-3721 was added to the stirred tank, and stirred at 20 RPM under vacuum for 3 hours to obtain the encapsulating adhesive.

[0034] Comparative Example 2

[0035] a. By mass fraction: 130g of 4,4'-bis(2-hydroxyethoxy)biphenyl and 190g of N,N-dimethylformamide were added to a reaction vessel and stirred at 10 RPM for 1 hour until completely dissolved; 170g of 40% sodium hydroxide aqueous solution was added, heated to 85℃, and stirred under vacuum at 10 RPM for 2 hours; 2g of benzyltriethylammonium chloride was added, and 510g of epichlorohydrin was added dropwise, completing the process within 30 minutes; the temperature was raised to 120℃, and the stirring was refluxed at 20 RPM for 6 hours; the mixture was then cooled to room temperature; the resin was washed twice with a 3:1 mixture of anhydrous ethanol and acetone, and dried at 60℃ for 2 hours to obtain the self-synthesized liquid crystal epoxy resin.

[0036] b. By mass parts: 100g of resorcinol, 550g of 2,6-bis(hydroxymethyl)-p-cresol, and 350g of 40% formaldehyde aqueous solution were sequentially added to a reaction vessel. Under nitrogen protection, the mixture was stirred at 10 RPM for 1 hour until homogeneous. 3g of oxalic acid was added, and the mixture was heated to 55℃. Under nitrogen protection, the mixture was stirred at 20 RPM for 2 hours and then heated to 95℃. The mixture was washed three times with deionized water, heated to 120℃, and stirred at 20 RPM under vacuum for 3 hours to obtain the self-synthesized linear phenolic resin.

[0037] c. By mass parts: 200g of self-synthesized liquid crystal epoxy resin, 250g of bisphenol F epoxy resin, and 350g of self-synthesized linear phenolic resin were sequentially added to a stirred tank, heated to 50℃, and stirred at 30 RPM for 2 hours; after cooling to room temperature, 100g of polyether-modified epoxy resin YLSE-2000 and 40g of fumed silica were sequentially added to the stirred tank, and stirred at 30 RPM under vacuum for 2 hours; 60g of microencapsulated imidazole compound was added to the stirred tank, and stirred at 20 RPM under vacuum for 3 hours to obtain the encapsulating adhesive.

[0038] Comparative Example 3

[0039] a. By mass fraction: 130g of 4,4'-bis(2-hydroxyethoxy)biphenyl and 190g of N,N-dimethylformamide were added to a reaction vessel and stirred at 10 RPM for 1 hour until completely dissolved; 170g of 40% sodium hydroxide aqueous solution was added, heated to 85℃, and stirred under vacuum at 10 RPM for 2 hours; 2g of benzyltriethylammonium chloride was added, and 510g of epichlorohydrin was added dropwise, completing the process within 30 minutes; the temperature was raised to 120℃, and the stirring was refluxed at 20 RPM for 6 hours; the mixture was then cooled to room temperature; the resin was washed twice with a 3:1 mixture of anhydrous ethanol and acetone, and dried at 60℃ for 2 hours to obtain the self-synthesized liquid crystal epoxy resin.

[0040] b. By mass parts: 250g of self-synthesized liquid crystal epoxy resin and 350g of p-o-cresol epoxy resin SRN-1730 were sequentially added to a stirred tank, heated to 50℃, and stirred at 30 RPM for 2 hours; after cooling to room temperature, 150g of polyether modified epoxy resin YLSE-2000 and 40g of fumed silica were sequentially added to a stirred tank, and stirred at 30 RPM under vacuum for 2 hours; 210g of microencapsulated imidazole compound HX-3721 was added to a stirred tank, and stirred at 20 RPM under vacuum for 3 hours to obtain the encapsulating adhesive.

[0041] The following tests were conducted to evaluate the performance of the sealing adhesives from Examples 1-3 and Comparative Examples 1-3 of the present invention. The single-component workability was characterized by the rate of change of the adhesive viscosity; a smaller rate of change indicates better workability. Adhesive performance was characterized by shear strength; a larger value indicates better adhesive performance. Flexibility was characterized by elongation at break; a larger value indicates better flexibility. Moisture and heat resistance was characterized by the rate of change of shear strength under high temperature and high humidity conditions; a smaller rate of change indicates better moisture and heat resistance. High and low temperature resistance was characterized by the appearance of the adhesive layer after curing under alternating high and low temperature conditions; no cracking in the adhesive layer indicates good high and low temperature resistance. Electrical insulation performance was characterized by the volume resistivity under high temperature and high humidity conditions; a larger value indicates better electrical insulation performance.

[0042] Test Example 1: Operability Test

[0043] Using an Anton Paar viscometer, C35-2 rotor, at 20 rpm, the viscosity value at 25±1℃ was measured, and the 8-hour change rate was calculated as a percentage (%).

[0044] Experimental Example 2: Adhesion Performance Test

[0045] Using a universal testing machine, with FR4 Vs PCB material selected, the shear strength before and after damp heat aging was tested according to the "Tensive Shear Strength Test Method for Adhesives" at a temperature of 25℃ and a shear rate of 10mm / min. The unit is megapascals (MPa). The attenuation rate before and after damp heat aging was calculated as a percentage (%).

[0046] Experimental Example 3: Flexibility Performance Test

[0047] Using a universal testing machine, test the elongation at break according to the "Test of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber", in percentage (%).

[0048] Test Example 4: Moisture and Heat Resistance Test

[0049] Using a high temperature and high humidity chamber, the temperature was set to 85℃ and the humidity to 85%RH. The sample was placed for 168 hours and then removed and placed at room temperature for 4 hours. Using a universal testing machine, FR4 Vs PCB material was selected, and the shear strength was tested according to the "Tensive Shear Strength Test Method for Adhesives" at a temperature of 25℃ and a shear rate of 10mm / min. The change rate was calculated as a percentage (%).

[0050] Test Example 5: High and Low Temperature Resistance Test

[0051] Using a high and low temperature thermal shock chamber, set the conditions to -40 to 125℃, and after 500 cycles, observe whether the adhesive layer of the sample cracks.

[0052] Test Example 6: Electrical Insulation Performance Test

[0053] Using a high temperature and high humidity environment chamber, set the temperature to 85℃ and the humidity to 85%, place the functional sample filled with encapsulant in the chamber for 1000 hours. After powering on with a 5V DC power supply, use an insulation resistance tester to test the volume resistivity of the functional sample after damp heat aging, in ohms (Ω).

[0054] The test results are shown in Table 1 below.

[0055] Table 1. Test results of samples prepared in Examples 1-3 and Comparative Examples 1-3

[0056] As can be seen from the shear strength and decay rate data in Table 1, the combined use of self-synthetic liquid crystal epoxy resin and self-synthetic linear phenolic resin significantly enhances the adhesive properties and resistance to damp heat, outperforming the use of either alone. The volume resistivity data in Table 1 shows that the self-synthetic liquid crystal epoxy resin significantly enhances the electrical insulation properties. The viscosity change rate data in Table 1 shows that the self-synthetic linear phenolic resin significantly enhances the workability. The encapsulating adhesive prepared in this invention possesses advantages such as good single-component workability, good adhesive properties, good flexibility, good resistance to damp heat, good resistance to high and low temperatures, and good electrical insulation properties, making it suitable for sealing and protecting circuit boards in various types of automotive modules.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A vehicle-mounted sealing adhesive with good resistance to moisture and heat, characterized in that, The product comprises, by weight, 10-25 parts of self-synthesized liquid crystal epoxy resin, 15-35 parts of p-o-cresol epoxy resin, 32-37 parts of self-synthesized linear phenolic resin, 10-15 parts of polyether modified epoxy resin, 3-4 parts of fumed silica, and 5-7 parts of microencapsulated imidazole compound. The specific structural formula of the self-synthesized liquid crystal epoxy resin is as follows: ； The specific structural formula of the self-synthesized linear phenolic resin is as follows: 。 2. The automotive sealing adhesive with good resistance to moisture and heat according to claim 1, characterized in that, The self-synthesized liquid crystal epoxy resin is prepared from the following raw materials in parts by weight: 13-14 parts of 4,4'-bis(2-hydroxyethoxy)biphenyl, 18-19 parts of N,N-dimethylformamide, 17-19 parts of 40% sodium hydroxide aqueous solution, 0.2-0.3 parts of benzyltriethylammonium chloride, and 49-51 parts of epichlorohydrin.

3. The automotive sealing adhesive with good resistance to moisture and heat according to claim 1, characterized in that, The self-synthesized linear phenolic resin is prepared from the following raw materials in parts by weight: 10-15 parts of m-methylphenol, 45-55 parts of 2,6-bis(hydroxymethyl)-p-cresol, 35-40 parts of 40% formaldehyde aqueous solution, and 0.3-0.5 parts of oxalic acid.

4. The automotive sealing adhesive with good resistance to moisture and heat according to claim 1, characterized in that, The self-synthesized liquid crystal epoxy resin is a biphenyl-type liquid crystal epoxy resin with a softening point of 80-85℃ and an epoxy equivalent of 190-200 g / eq; the p-o-cresol epoxy resin is a phenolic epoxy resin with a viscosity of 3000-5000 mPa·s at 25℃ and an epoxy equivalent of 155-175 g / eq; the self-synthesized linear phenolic resin is a high-ortho-linear phenolic resin with a softening point of 80-85℃ and a hydroxyl equivalent of 105-110 g / eq; the polyether-modified epoxy resin is a flexible epoxy resin with a viscosity of 1500-3000 mPa·s at 25℃ and an epoxy equivalent of 240-260 g / eq; the microencapsulated imidazole compound is an imidazole compound with a viscosity of 110000-250000 mPa·s at 25℃ and a gel time of 11-13 min at 80℃.

5. The automotive encapsulating adhesive with good resistance to damp heat according to claim 1 is prepared as follows: a. By mass parts: 13-14 parts of 4,4'-bis(2-hydroxyethoxy)biphenyl and 18-19 parts of N,N-dimethylformamide were added to a reaction vessel and stirred at 10 RPM for 1-2 hours until completely dissolved; 17-19 parts of 40% sodium hydroxide aqueous solution were added, and the mixture was heated to 85-95℃ and stirred under vacuum at 10 RPM for 1-2 hours; 0.2-0.3 parts of benzyltriethylammonium chloride were added, and 49-51 parts of epichlorohydrin were added dropwise within 30 minutes; the mixture was heated to 110-120℃ and stirred under reflux at 20 RPM for 4-6 hours; the mixture was then cooled to room temperature; the mixture was washed 2-3 times with a 3:1 mixture of anhydrous ethanol and acetone, and dried at 60℃ for 1-2 hours to obtain the self-synthesized liquid crystal epoxy resin; b. By mass parts: 10-15 parts of m-methylphenol, 45-55 parts of 2,6-dihydroxymethyl-p-cresol, and 35-40 parts of 40% formaldehyde aqueous solution are sequentially added to a reaction vessel. Under nitrogen protection, the stirring speed is set to 10 RPM and stirred for 0.5-1 h until the mixture is homogeneous. 0.3-0.5 parts of oxalic acid are added, and the mixture is heated to 55-65℃. Under nitrogen protection, the stirring speed is set to 20 RPM and stirred for 1-2 h. The mixture is then heated to 90-95℃. The mixture is washed 3-4 times with deionized water, heated to 110-120℃, and under vacuum, the stirring speed is set to 20 RPM and stirred for 2-3 h to obtain the self-synthesized linear phenolic resin. c. By mass parts: 10-25 parts of self-synthesized liquid crystal epoxy resin, 15-35 parts of p-cresol epoxy resin, and 32-37 parts of self-synthesized linear phenolic resin are sequentially added to a stirred tank, heated to 45-55℃, and stirred at 30 RPM for 2-3 hours; cooled to room temperature, 10-15 parts of polyether-modified epoxy resin and 3-4 parts of fumed silica are sequentially added to the stirred tank, and stirred at 30 RPM under vacuum for 1-2 hours; 5-7 parts of microencapsulated imidazole compound are added to the stirred tank, and stirred at 20 RPM under vacuum for 2-3 hours to obtain the encapsulating adhesive.

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