Room-temperature curing low-density flame-retardant epoxy adhesive for pouring reinforced honeycomb sandwich structure and preparation method of room-temperature curing low-density flame-retardant epoxy adhesive

Abstract

The invention relates to an epoxy adhesive and a preparation method thereof, in particular to a room-temperature curing low-density flame-retardant epoxy adhesive for pouring and reinforcing a honeycomb sandwich structure and a preparation method thereof. The invention aims to solve the problems that the existing epoxy adhesive does not have low density, high compressive strength and flame retardant property and cannot improve the compressive strength of a honeycomb sandwich structure. The invention relates to a room-temperature curing low-density flame-retardant epoxy adhesive for pouring and reinforcing a honeycomb sandwich structure. The room-temperature curing low-density flame-retardant epoxy adhesive consists of a component A and a component B, the component A is prepared from modified epoxy resin, a flame retardant and modified hollow glass beads in parts by weight; and the component B is prepared from modified amine and an accelerant in parts by weight. The room-temperature-curing low-density flame-retardant epoxy adhesive prepared by the invention can be cured at room temperature, can also be cured by heating, is suitable for pouring in viscosity, low in density, excellent in flame-retardant property, strong in bonding force to aluminum alloy materials, good in compression resistance and suitable for reinforcement and edge sealing of honeycomb sandwich structures with flame-retardant requirements.

Description

Technical Field

[0001] The present invention relates to an epoxy adhesive and a preparation method thereof. Background Art

[0002] The honeycomb sandwich structure refers to a laminated composite material with a lightweight core material sandwiched between two thin skins. The core layer of the honeycomb sandwich structure is a series of hexagonal cells made of metal materials (such as aluminum), fiberglass cloth, or paper materials. Thinner face sheets are adhesively bonded (or brazed) to the upper and lower surfaces of the core layer. The honeycomb sandwich structure has higher strength and stiffness than other sandwich structures. Compared with the riveted structure, the structural efficiency can be increased by 15%-30%. Since the solid volume of the honeycomb core only accounts for 1%-3%, and the rest of the space is filled with air in a sealed state, the overall structure is lightweight. The porous structure of the honeycomb material gives it good heat insulation and sound insulation effects, so it also has good thermal insulation performance. The honeycomb core itself also has functions such as flow guiding, electromagnetic shielding, and buffering and energy absorption.

[0003] Honeycomb sandwich structure composites have been widely used in the primary and secondary load-bearing structures of aircraft, such as wings, fuselages, tails, floors, interior decorations, etc. Paper honeycomb core panels are also widely used in the construction field, such as materials for workshop, office partition walls, exterior walls of steel structure buildings, etc. They are also used in various partitions on trains, subways, and cars, as well as sports goods such as water skis, surfboards, and snowboards.

[0004] Honeycomb composites have the characteristics of high strength, compression resistance, and bending resistance, and can withstand large pressures and tensions, and are not easily deformed or broken. When designing the honeycomb composite structure, some stressed parts need structural reinforcement to increase the compressive strength of the honeycomb structure; some parts need to be drilled, and in this process, the honeycomb structure will be damaged, affecting the mechanical properties of the overall structure. To reduce this adverse effect, it is necessary to locally strengthen the honeycomb sandwich structure of this part to increase the compressive strength of this part or reduce the adverse effects brought about after drilling; in addition, the honeycomb edges need to be edge-sealed. Honeycomb edge-sealing can effectively reinforce the edges of the honeycomb panel, prevent corner wear and deformation, thereby improving the overall structural stability, and also has good sealing and corrosion resistance, and can effectively isolate moisture, oxygen, and corrosive substances in the external environment, thereby extending the service life of the honeycomb composite material.

[0005] Epoxy resin adhesives are widely used in the bonding and potting of composites, metals, etc. due to their high bonding strength, simple process, fatigue resistance, and good corrosion resistance. Epoxy resin adhesives can be used for the potting reinforcement of honeycomb sandwich structures, and their density is approximately (1.1-1.3) g / cm 3, however, compared with the honeycomb sandwich structure with relatively low mass, its density is slightly higher. Moreover, the flame retardant property of epoxy resin is slightly poor, so it cannot be applied to structural areas with high flame retardant requirements, which to a certain extent limits the application of epoxy adhesives. Therefore, developing a room temperature curable epoxy adhesive with low density, high compressive strength and flame retardant property can effectively meet the special requirements of honeycomb sandwich structures. Summary of the Invention

[0006] The object of the present invention is to solve the problem that existing epoxy adhesives do not have low density, high compressive strength and flame retardant property and cannot improve the compressive strength of honeycomb sandwich structures, and to provide a room temperature curable low density flame retardant epoxy adhesive for pouring and strengthening honeycomb sandwich structures and its preparation method.

[0007] A room temperature curable low density flame retardant epoxy adhesive for pouring and strengthening honeycomb sandwich structures consists of component A and component B, and the mass ratio of component A to component B is 100:(31 - 35);

[0008] The component A is made of 95 - 105 parts by weight of modified epoxy resin, 10 - 15 parts by weight of flame retardant and 25 - 30 parts by weight of modified hollow glass microspheres;

[0009] The component B is made of 28 - 32 parts by weight of modified amine and 3 - 5 parts by weight of accelerator.

[0010] The preparation method of the component A is specifically completed according to the following steps:

[0011] I. Weigh 95 - 105 parts by weight of modified epoxy resin, 10 - 15 parts by weight of flame retardant and 25 - 30 parts by weight of modified hollow glass microspheres;

[0012] II. Add the 95 - 105 parts by weight of modified epoxy resin and 10 - 15 parts by weight of flame retardant weighed in step I into a reactor, stir and mix for 20 min under the condition that the stirring speed is 900 r / min - 1100 r / min, then add 25 - 30 parts by weight of modified hollow glass microspheres, and then stir and mix for 30 min under the condition that the stirring speed is 300 r / min - 500 r / min to obtain component A.

[0013] The preparation method of the component B is specifically completed according to the following steps:

[0014] I. Weigh 28 - 32 parts by weight of modified amine and 3 - 5 parts by weight of accelerator;

[0015] II. Add the 28 - 32 parts by weight of modified amine and 3 - 5 parts by weight of accelerator weighed in step I into a reactor, and stir and mix evenly at room temperature to obtain component B.

[0016] Principle and advantages of the present invention:

[0017] I. A room-temperature curing, low-density, flame-retardant epoxy adhesive for perfusion-enhanced honeycomb sandwich structures prepared by the present invention can be cured at room temperature or by heating. It has an appropriate viscosity for perfusion, a low density, excellent flame-retardant properties, a strong adhesion to aluminum alloy materials, and good compression resistance. It can be applied to the reinforcement and edge sealing of honeycomb sandwich structures with flame-retardant requirements. The present invention solves the problem of a room-temperature curing, low-density, flame-retardant epoxy adhesive for perfusion-enhanced honeycomb sandwich structures having both low density, high compression performance, and good shear strength from two aspects of component A and component B. In the resin system of component A, a toughened modified epoxy resin system is compounded with a low-density filler of modified hollow glass microspheres and a flame retardant. In the curing agent system of component B, a modified amine and a modified piperazine accelerator with phenolic hydroxyl groups are compounded to form a curing system that can be cured at room temperature.

[0018] II. The curing conditions of a room-temperature curing, low-density, flame-retardant epoxy adhesive for perfusion-enhanced honeycomb sandwich structures prepared by the present invention are one of room temperature / 7 days, room temperature / 6 h + 120 °C / 1.5 h, and room temperature / 6 h + 177 °C / 1 h.

[0019] The viscosity of the mixed adhesive of component A and component B is (11000 - 26000) mPa·s at (25 ± 1) °C.

[0020] The density of the cured adhesive is (0.87 - 0.90) g / cm at (25 ± 3) °C 3 ;

[0021] The compression strength of the cured adhesive is (90.6 - 99.4) MPa at (23 ± 5) °C.

[0022] The compression modulus of the cured adhesive is (2621 - 3102) MPa at (23 ± 5) °C.

[0023] The compression strength of the cured adhesive is (10.4 - 13.5) MPa at (177 ± 5) °C.

[0024] The compression modulus of the cured adhesive is (80.5 - 103.7) MPa at (177 ± 5) °C.

[0025] The tensile shear strength of the adhesive bonding LY12CZ aluminum is (18.5 - 20.4) MPa at (23 ± 5) °C.

[0026] The horizontal burning rate of the cured adhesive is (0 - 3) mm / min in 15 s.

[0027] The present invention can obtain a room-temperature curing, low-density, flame-retardant epoxy adhesive for perfusion-enhanced honeycomb sandwich structures. Detailed implementation manners

[0028] Embodiment 1: A room-temperature curing low-density flame-retardant epoxy adhesive for perfusion-reinforced honeycomb sandwich structure consists of component A and component B, and the mass ratio of component A to component B is 100:(31 - 35);

[0029] The described component A is made of 95 - 105 parts by weight of modified epoxy resin, 10 - 15 parts by weight of flame retardant, and 25 - 30 parts by weight of modified hollow glass microspheres;

[0030] The described component B is made of 28 - 32 parts by weight of modified amine and 3 - 5 parts by weight of accelerator.

[0031] Embodiment 2: The difference between this embodiment and Embodiment 1 is: The preparation method of the described modified epoxy resin is specifically completed according to the following steps:

[0032] Add 60g of E51 epoxy resin, 2g - 3g of dimer acid, and 0.05g of triphenylphosphine into the reactor, and heat from room temperature to 110°C - 120°C at a heating rate of 1°C / min - 3°C / min under the condition of a stirring speed of 300r / min - 500r / min, continuously stir for 3h - 4h at 110°C - 120°C. When the temperature of the above resin drops to room temperature, then add 30g - 40g of high-functional epoxy resin, and then stir and mix for 30min under the condition of a stirring speed of 300r / min - 500r / min to obtain the modified epoxy resin. Other steps are the same as those in Embodiment 1.

[0033] Embodiment 3: The difference between this embodiment and either Embodiment 1 or 2 is: The viscosity of the described dimer acid at 25°C is 6000mPa·s - 10000mPa·s; The described high-functional epoxy resin is one of AG80 and TDE-85. Other steps are the same as those in Embodiment 1 or 2.

[0034] Embodiment 4: The difference between this embodiment and any one of Embodiments 1 to 3 is: The described flame retardant is Doher-9000A, purchased from Dongguan Daoer New Material Technology Co., Ltd. Other steps are the same as those in Embodiments 1 to 3.

[0035] Embodiment 5: The difference between this embodiment and any one of Embodiments 1 to 4 is: The preparation method of the described modified hollow glass microspheres is specifically completed according to the following steps:

[0036] Add 100 g of absolute ethanol, 1 g of titanate coupling agent, and 20 g of hollow glass microspheres into the reactor, continuously stir for 2 h to 4 h at room temperature and a stirring speed of 400 r / min to 600 r / min, filter the product to remove the solvent, and obtain a solid product; dry the solid product at 50 °C to 60 °C for 2 h to 4 h to obtain modified hollow glass microspheres. Other steps are the same as those in Embodiments 1 to 4.

[0037] Embodiment 6: The difference between this embodiment and any one of Embodiments 1 to 5 is that the titanate coupling agent is one of isopropyl dioleoyl oxy (dioctyl phosphate oxy) titanate, isopropyl tris (dioctyl phosphate oxy) titanate, isopropyl tris (dioctyl pyrophosphate oxy) titanate, bis (dioctyloxy pyrophosphate ester group) ethylene titanate, and tetra isopropyl bis (dioctyl phosphite oxy) titanate; the hollow glass microspheres are 38P5500, purchased from Sinosteel Maanshan Institute of Mining New Materials Technology Co., Ltd. Other steps are the same as those in Embodiments 1 to 5.

[0038] Embodiment 7: The difference between this embodiment and any one of Embodiments 1 to 6 is that the preparation method of the modified amine is specifically completed according to the following steps:

[0039] First, add 75 g of m-xylene diamine and 25 g of isophorone diamine into the reactor, stir at a speed of 300 r / min to 500 r / min at room temperature for 10 min, then add 5 g of E51 epoxy resin, continue to stir at a speed of 300 r / min to 500 r / min at room temperature for 10 min, and then heat from room temperature to 75 °C to 80 °C at a heating rate of 2 °C / min to 4 °C / min under stirring conditions, and stir at 75 °C to 80 °C for 3 h to 4 h to obtain the modified amine. Other steps are the same as those in Embodiments 1 to 6.

[0040] Embodiment 8: The difference between this embodiment and any one of Embodiments 1 to 7 is that the preparation method of the promoter is specifically completed according to the following steps:

[0041] First, add N-aminoethyl piperazine and phenol into the reactor, heat from room temperature to 80 °C to 85 °C at a heating rate of 2 °C / min to 4 °C / min under the condition of a stirring speed of 200 r / min to 500 r / min, then add paraformaldehyde in portions, and then heat from 80 °C to 85 °C to 100 °C to 105 °C, and reflux and react at 100 °C to 105 °C for 3 h to 4 h to obtain the reaction solution after reflux; then control the vacuum degree to more than 0.09 MPa, carry out vacuum dehydration on the reaction solution after reflux, and stop vacuum dehydration when the solution temperature reaches 120 °C to obtain the promoter;

[0042] The molar mass ratio of the described N-aminoethylpiperazine to phenol is (0.9 - 1.1):2;

[0043] The molar mass ratio of the described N-aminoethylpiperazine to paraformaldehyde is (0.9 - 1.1):2. Other steps are the same as those in Embodiments 1 to 7.

[0044] Embodiment 9: The difference between this embodiment and any one of Embodiments 1 to 8 is that the preparation method of the component A is specifically completed according to the following steps:

[0045] 1. Weigh 95 to 105 parts by weight of modified epoxy resin, 10 to 15 parts by weight of flame retardant, and 25 to 30 parts by weight of modified hollow glass microspheres to make it;

[0046] 2. Add the 95 to 105 parts by weight of modified epoxy resin and 10 to 15 parts by weight of flame retardant weighed in step 1 into a reactor, stir and mix for 20 minutes under the condition of a stirring speed of 900 r / min to 1100 r / min, then add 25 to 30 parts by weight of modified hollow glass microspheres, and then stir and mix for 30 minutes under the condition of a stirring speed of 300 r / min to 500 r / min to obtain component A. Other steps are the same as those in Embodiments 1 to 8.

[0047] Embodiment 10: The difference between this embodiment and any one of Embodiments 1 to 9 is that the preparation method of the component B is specifically completed according to the following steps:

[0048] 1. Weigh 28 to 32 parts by weight of modified amine and 3 to 5 parts by weight of accelerator;

[0049] 2. Add the 28 to 32 parts by weight of modified amine and 3 to 5 parts by weight of accelerator weighed in step 1 into a reactor, and stir and mix evenly at room temperature to obtain component B. Other steps are the same as those in Embodiments 1 to 9.

[0050] The following examples are used to verify the beneficial effects of the present invention:

[0051] Example 1: A room-temperature curing low-density flame-retardant epoxy adhesive for perfusion-enhanced honeycomb sandwich structures, which consists of component A and component B, and the mass ratio of component A to component B is 100:33;

[0052] The described component A is made of modified epoxy resin, flame retardant, and modified hollow glass microspheres, and the mass ratio of modified epoxy resin, flame retardant, and modified hollow glass microspheres is 100:13:28; The preparation method is specifically completed according to the following steps:

[0053] 1. Weigh modified epoxy resin, flame retardant, and modified hollow glass microspheres to make it;

[0054] II. Add the weighed modified epoxy resin and flame retardant into a reactor, stir and mix them for 20 min under the condition that the stirring speed is 1000 r / min, then add modified hollow glass microspheres, and then stir and mix them for 30 min under the condition that the stirring speed is 500 r / min to obtain Component A.

[0055] The preparation method of the described modified epoxy resin is specifically completed according to the following steps:

[0056] Add 60 g of E51 epoxy resin, 2 g - 3 g of dimer acid, and 0.05 g of triphenylphosphine into a reactor, heat up from room temperature to 110 °C at a heating rate of 3 °C / min under the condition that the stirring speed is 300 r / min, continuously stir for 4 h at 110 °C, when the temperature of the above resin drops to room temperature, then add 30 g of high-functional epoxy resin, and then stir and mix for 30 min under the condition that the stirring speed is 300 r / min to obtain the modified epoxy resin; the viscosity of the described dimer acid at 25 °C is 8600 mPa·s; the high-functional epoxy resin is AG80;

[0057] The described flame retardant is Doher-9000A, purchased from Dongguan Daoer New Material Technology Co., Ltd.;

[0058] The preparation method of the described modified hollow glass microspheres is completed according to the following steps:

[0059] Add 100 g of absolute ethanol, 1 g of titanate coupling agent, and 20 g of hollow glass microspheres into a reactor, continuously stir for 3 h at room temperature and under the condition that the stirring speed is 500 r / min, filter the product to remove the solvent to obtain a solid product; dry the solid product at 60 °C for 3 h to obtain the modified hollow glass microspheres; the titanate coupling agent is isopropyl dioleate acyloxy (dioctyl phosphate acyloxy) titanate; the hollow glass microspheres are 38P5500, purchased from Sinosteel Maanshan Institute of Mining New Material Technology Co., Ltd.

[0060] Component B is made of modified amine and accelerator, and the mass ratio of the modified amine to the accelerator is 29:4;

[0061] The preparation method is specifically completed according to the following steps:

[0062] I. Weigh the modified amine and accelerator;

[0063] II. Add the weighed modified amine and accelerator into a reactor, stir and mix them evenly to obtain Component B.

[0064] The preparation method of the described modified amine is specifically completed according to the following steps:

[0065] First, add 75 g of m-xylenediamine and 25 g of isophorone diamine into the reactor, stir at a speed of 300 r / min for 10 min at room temperature, then add 5 g of E51 epoxy resin, continue to stir at a speed of 300 r / min for 10 min at room temperature, and then heat up from room temperature to 75 °C at a heating rate of 2 °C / min under stirring conditions, and stir at 75 °C for 4 h to obtain the modified amine;

[0066] The preparation method of the accelerator is specifically completed according to the following steps:

[0067] First, add N-aminoethylpiperazine and phenol into the reactor, heat up from room temperature to 80 °C at a heating rate of 2 °C / min under the condition that the stirring speed is 300 r / min, then add paraformaldehyde in portions (add in three portions), and then heat up from 80 °C to 100 °C, and reflux and react at 100 °C for 4 h to obtain the reacted liquid after reflux; then control the vacuum degree to above 0.09 MPa, carry out vacuum dehydration on the reacted liquid after reflux, and stop vacuum dehydration when the solution temperature reaches 120 °C to obtain the accelerator; the molar mass ratio of the N-aminoethylpiperazine to the phenol is 1:2; the molar mass ratio of the N-aminoethylpiperazine to the paraformaldehyde is 1:2.

[0068] Example 2: The difference between this example and Example 1 is that the component A is made of modified epoxy resin, flame retardant, and modified hollow glass microspheres, and the mass ratio of the modified epoxy resin, flame retardant, and modified hollow glass microspheres is 100:13:30. Other steps and parameters are the same as those in Example 1.

[0069] Example 3: The difference between this example and Example 1 is that the component A is made of modified epoxy resin, flame retardant, and modified hollow glass microspheres, and the mass ratio of the modified epoxy resin, flame retardant, and modified hollow glass microspheres is 100:13:25. Other steps and parameters are the same as those in Example 1.

[0070] Example 4: The difference between this example and Example 1 is that the component B is made of modified amine and accelerator, and the mass ratio of the modified amine to the accelerator is 29:5. Other steps and parameters are the same as those in Example 1.

[0071] Example 5: The difference between this example and Example 1 is that the component B is made of modified amine and accelerator, and the mass ratio of the modified amine to the accelerator is 29:3. Other steps and parameters are the same as those in Example 1.

[0072] Control Example 1: The difference between this example and Example 1 is that the modified hollow glass microspheres in the component A are replaced with unmodified hollow glass microspheres. Other steps and parameters are the same as those in Example 1.

[0073] Comparative Example 2: The difference between this example and Example 1 is that the accelerator is omitted in the B component. Other steps and parameters are the same as those in Example 1.

[0074] Table 1 shows the properties of the room-temperature-curing low-density flame-retardant epoxy adhesives for perfusion-reinforced honeycomb sandwich structures prepared in Examples 1 to 5, Comparative Example 1, and Comparative Example 2. The curing conditions are room temperature / 7 days;

[0075] Table 1

[0076]

[0077] The titanate coupling agent-modified hollow glass microspheres in the present invention have good dispersion performance in epoxy resin. After addition, they can effectively enhance the compression performance and tensile shear strength of the adhesive. In addition, after the addition of the accelerator in the present invention, the room-temperature-curing performance of the adhesive can be effectively improved, enabling the room-temperature-curing low-density flame-retardant epoxy adhesive for perfusion-reinforced honeycomb sandwich structures prepared in the present invention to have good room-temperature-curing characteristics and good mechanical properties.

Claims

1. A room temperature curing low density flame retardant epoxy adhesive for infusion reinforced honeycomb sandwich structure, characterized in that The room temperature curing low-density flame-retardant epoxy adhesive consists of component A and component B, and the mass ratio of component A to component B is 100:(31-35); The component A is made of 95 to 105 parts by weight of modified epoxy resin, 10 to 15 parts of flame retardant, and 25 to 30 parts of modified hollow glass microspheres; The component B is prepared from 28 to 32 parts of modified amine and 3 to 5 parts of accelerator by weight.

2. A room temperature curing low density flame retardant epoxy adhesive for infusion reinforced honeycomb sandwich structure according to claim 1, characterized in that The preparation method of the modified epoxy resin is specifically completed according to the following steps: Add 60g E51 epoxy resin, 2g-3g dimer acid, and 0.05g triphenylphosphine into the reactor, and heat from room temperature to 110°C-120°C at a heating rate of 1°C / min-3°C / min under a stirring speed of 300r / min-500r / min. Stir continuously at 110°C-120°C for 3h-4h. When the temperature of the above resin drops to room temperature, add 30g-40g high-functional epoxy resin, and then stir and mix for 30min under a stirring speed of 300r / min-500r / min to obtain a modified epoxy resin.

3. A room temperature curing low density flame retardant epoxy adhesive for infusion reinforced honeycomb sandwich structure according to claim 2, characterized in that The viscosity of the dimer acid at 25° C. is 6000 mPa·s to 10000 mPa·s; the high-functional epoxy resin is one of AG80 and TDE-85.

4. A room temperature curing low density flame retardant epoxy adhesive for infusion reinforced honeycomb sandwich structure according to claim 1, characterized in that The flame retardant is Doher-9000A.

5. A room temperature curing low density flame retardant epoxy adhesive for infusion reinforced honeycomb sandwich structure according to claim 1, characterized in that The preparation method of the modified hollow glass microspheres is completed according to the following steps: Add 100 g of anhydrous ethanol, 1 g of a titanate coupling agent, and 20 g of hollow glass microspheres into a reactor, stir continuously for 2 h to 4 h at room temperature and a stirring speed of 400 r / min to 600 r / min, filter the product, remove the solvent, and obtain a solid product; The solid product is dried at 50° C. to 60° C. for 2 h to 4 h to obtain modified hollow glass microspheres.

6. A room temperature curing low density flame retardant epoxy adhesive for infusion reinforced honeycomb sandwich structure according to claim 5, characterized in that The titanate coupling agent is one of isopropyl dioleyloxy (dioctyl phosphate acyloxy) titanate, isopropyl tris (dioctyl phosphate acyloxy) titanate, isopropyl tris (dioctyl pyrophosphate acyloxy) titanate, bis (dioctyl pyrophosphate) ethylene titanate, and tetraisopropyl di (dioctyl phosphite acyloxy) titanate; the hollow glass microsphere is 38P5500.

7. A room temperature curing low density flame retardant epoxy adhesive for infusion reinforced honeycomb sandwich structure according to claim 1, characterized in that The preparation method of the modified amine is specifically completed according to the following steps: First, add 75g of m-phenylenediamine and 25g of isophoronediamine into the reactor, stir at 300r / min-500r / min for 10min at room temperature, then add 5g of E51 epoxy resin, continue stirring at 300r / min-500r / min for 10min at room temperature, then heat the mixture from room temperature to 75°C-80°C at a heating rate of 2°C / min-4°C / min under stirring, stir at 75°C-80°C for 3h-4h to obtain modified amine.

8. The room temperature curing low density flame retardant epoxy adhesive for infusion reinforced honeycomb sandwich structure according to claim 1, characterized in that The preparation method of the accelerator is specifically completed according to the following steps: First, N-aminoethylpiperazine and phenol are added to the reactor, and the temperature is raised from room temperature to 80°C to 85°C at a heating rate of 2°C / min to 4°C / min under a stirring speed of 200 r / min to 500 r / min, and then paraformaldehyde is added in portions, and then the temperature is raised from 80°C to 85°C to 100°C to 105°C, and refluxed at 100°C to 105°C for 3h to 4h to obtain a refluxed reaction solution; then the vacuum degree is controlled to be above 0.09 MPa, and the refluxed reaction solution is decompressed and dehydrated, and when the solution temperature reaches 120°C, the decompression and dehydration are stopped to obtain a promoter; The molar mass ratio of N-aminoethylpiperazine to phenol is (0.9-1.1):2; The molar mass ratio of the N-aminoethylpiperazine to the paraformaldehyde is (0.9-1.1):

2.

9. A room temperature curing low density flame retardant epoxy adhesive for infusion reinforced honeycomb sandwich structure according to claim 1, characterized in that The preparation method of the component A is specifically completed according to the following steps:

1. Weigh 95 to 105 parts of modified epoxy resin, 10 to 15 parts of flame retardant, and 25 to 30 parts of modified hollow glass microspheres by weight; 2. Add 95 to 105 parts of modified epoxy resin and 10 to 15 parts of flame retardant weighed in step 1 into the reactor, stir and mix for 20 minutes at a stirring speed of 900 r / min to 1100 r / min, then add 25 to 30 parts of modified hollow glass microspheres, and then stir and mix for 30 minutes at a stirring speed of 300 r / min to 500 r / min to obtain component A.

10. A room temperature curing low density flame retardant epoxy adhesive for infusion reinforced honeycomb sandwich structure according to claim 1, characterized in that The preparation method of component B is specifically completed according to the following steps:

1. Weigh 28 to 32 parts of modified amine and 3 to 5 parts of accelerator by weight; 2. Add 28 to 32 parts of modified amine and 3 to 5 parts of accelerator weighed in step 1 into the reactor, stir and mix evenly at room temperature to obtain component B.

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