High-temperature-resistant and aging-resistant polyurethane structural adhesive and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant and aging-resistant polyurethane structural adhesive and a preparation method thereof, and belongs to the technical field of structural adhesives. The high-temperature-resistant and aging-resistant polyurethane structural adhesive consists of a component A and a component B, wherein the component A is prepared from the following raw materials in parts by mass: 50 to 90 parts of first polyol, 20 to 40 parts of first filler, 10 to 20 parts of flame retardant, 5 to 15 parts of enhancer, 1 to 3 parts of thixotropic agent, 3 to 5 parts of molecular sieve, 0.1 to 1.0 part of antioxidant, 0.01 to 0.05 part of polyurethane environment-friendly organic bismuth catalyst BCAT-E20 and 0.01 to 0.05 part of triphenylphosphine; the component B is prepared from the following raw materials in parts by mass: 40 to 100 parts of isocyanate prepolymer and 10 to 50 parts of second filler. The invention also provides a preparation method of the composition. Compared with the prior art, the high-temperature-resistant and aging-resistant polyurethane structural adhesive prepared by the invention has the advantages of high impact resistance, high interface bonding strength, good flame retardance, high thermal aging resistance and the like.

Description

Technical Field

[0001] This invention relates to the field of polyurethane structural adhesives, and more particularly to a high-temperature resistant and aging-resistant polyurethane structural adhesive and its preparation method. Background Technology

[0002] Polyurethane structural adhesives possess excellent mechanical and processing properties, as well as corrosion and water resistance and good insulation, making them widely used in sealing and bonding applications. When used for bonding plastics and metals, polyurethane structural adhesives require good adhesion and sealing properties. They are extensively used in the electronics and electrical appliance industry, primarily for bonding and protecting electronic components. This necessitates low density, good mechanical and adhesive properties after curing, and the ability to prevent corrosion of electronic circuit board components.

[0003] CN114133910A discloses a high thermal conductivity two-component polyurethane structural adhesive, its preparation method, and its application. Component A is prepared from the following components in parts by weight: 10-50 parts polymeric polyol, 50-90 parts thermally conductive filler, and 0.5-5 parts silane coupling agent; Component B is prepared from the following components in parts by weight: 10-90 parts polyisocyanate and 10-90 parts thermally conductive filler, thus improving thermal conductivity. However, this invention may have the potential to reduce mechanical properties at higher ambient temperatures.

[0004] CN111777983A discloses a high-hardness, thermally conductive polyurethane structural adhesive and its preparation method, comprising a mass ratio of component A to component B of 100:15-48; component B is made from diisocyanate or diisocyanate and polyether polyol; prepolymer component A is a mixture of castor oil, polyether polyol, diluent, catalyst, thermally conductive filler, and other additives, wherein the polyether polyol is one or more of trifunctional or tetrafunctional polyether polyols. However, this invention may have the potential for lower flame retardant and mechanical properties. Summary of the Invention

[0005] In view of the above-mentioned defects of the prior art, the high-temperature resistant and aging-resistant polyurethane structural adhesive prepared by the present invention has the advantages of strong impact resistance, strong interfacial bonding strength, good flame retardancy and strong heat aging resistance.

[0006] To achieve the above objectives, the present invention provides a high-temperature resistant and aging-resistant polyurethane structural adhesive, which is composed of two components, A and B, with a mass ratio of component A to component B of 1:0.8-1.2. Component A comprises the following raw materials in parts by weight: 50-90 parts of a first polyol, 20-40 parts of a first filler, 0.1-1.0 parts of an antioxidant, 1-3 parts of a thixotropic agent, 10-20 parts of a flame retardant, 5-15 parts of a reinforcing agent, 3-5 parts of a molecular sieve, 0.01-0.05 parts of a polyurethane environmentally friendly organic bismuth catalyst BCAT-E20, and 0.01-0.05 parts of triphenylphosphine; Component B comprises the following raw materials in parts by weight: 40-100 parts isocyanate prepolymer and 10-50 parts second filler; The flame retardant is a hexadecylphenol-modified brominated epoxy resin; The reinforcing agent is polydimethylsiloxane modified with vinyl compounds.

[0007] Preferably, the first polyol is composed of a mixture of polyether polyol, polyester polyol and glycerol; the polyether polyol is selected from at least one of S215H polyether polyol, polyether triol C310 and polyether tetraol F414.

[0008] More preferably, the first polyol is composed of S215H polyether polyol, polyester polyol, and glycerol in a mass ratio of 1-10:1-5:0.1-1.

[0009] Preferably, the first filler is selected from at least one of kaolin, mica powder, and aluminum hydroxide; the antioxidant is selected from at least one of antioxidant 1010, antioxidant 168, and antioxidant DLTP.

[0010] Preferably, the thixotropic agent is selected from at least one of bentonite and polyamide wax.

[0011] Preferably, the preparation method of the hexadecylphenol modified brominated epoxy resin includes the following steps, in parts by weight: Mix 50-100 parts of brominated epoxy resin, 50-80 parts of hexadecylphenol and 0.1-1 parts of antioxidant 1010, then heat to 80-120℃, add 0.1-1.0 parts of triphenylphosphine, continue heating to 120-160℃, and react for 30-90 minutes to obtain hexadecylphenol modified brominated epoxy resin.

[0012] As a further explanation of the present invention, brominated epoxy resin can be prepared by undergoing a phenol-epoxy ring-opening addition reaction with hexadecylphenol to obtain brominated epoxy resin grafted with hexadecylphenol. The brominated epoxy resin grafted with hexadecylphenol can improve dispersibility and water resistance. In this process, the bromide decomposes upon heating to release bromine free radicals, which can effectively capture the key hydrogen free radicals and hydroxyl free radicals in the combustion chain reaction, thereby improving flame retardant performance.

[0013] Preferably, the preparation method of the reinforcing agent includes the following steps, in parts by mass: Step 1: Under nitrogen protection, react 30-50 parts of 1,3,5,7-tetramethylcyclotetrasiloxane, 10-30 parts of octamethylcyclotetrasiloxane, 5-15 parts of 1,1,3,3-tetramethyldisiloxane, and 1-5 parts of 0.3wt% trifluoromethanesulfonic acid aqueous solution at 20-30℃ for 20-30 hours. Then, add 20-40 parts of sodium bicarbonate to the above reaction solution and stir for 1-3 hours. Filter and collect the filtrate to obtain hydrogen-containing polysiloxane. Step 2: Mix 40-50 parts of modifier, 0.1-1 parts of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, and 20-40 parts of toluene evenly, then purge with nitrogen for protection, and then heat to 70-100℃ to obtain reaction solution 1; mix 25-40 parts of the hydrogen-containing polysiloxane obtained in Step 1 with 20-40 parts of toluene evenly and add it dropwise to the above reaction solution 1, completing the addition in 1-3 hours, then heat to 80-120℃ and react for 10-14 hours; remove the solvent to obtain the reinforcing agent.

[0014] Preferably, the modifier is selected from at least one of 1,2-epoxy-4-vinylcyclohexane, 3,4-epoxycyclohexyl methacrylate, and 4-vinylphenyl glycidyl ether.

[0015] As a further explanation of the present invention, hydrogen-containing polysiloxanes are synthesized by acid-catalyzed ring-opening polymerization, and then epoxy-containing modifiers are grafted onto the side chains of polysiloxanes using platinum-catalyzed hydrosilylation to obtain a reinforcing agent; the toughening of the flexible siloxane skeleton and the covalent cross-linking of the terminal epoxy groups significantly improve the impact resistance, interfacial bonding strength and heat aging resistance of the polyurethane structural adhesive.

[0016] Preferably, the preparation method of the isocyanate prepolymer includes the following steps: heating 40-60 parts of a second polyol and 1-5 parts of a plasticizer to 120-130°C and stirring under vacuum for 1-3 hours; cooling to 25-40°C, then adding diphenylmethane diisocyanate according to the stoichiometric ratio of 10-30% NCO content in the system after reaction, adding an appropriate amount of catalyst, heating to 60-80°C, stirring under vacuum for 2-4 hours, and cooling to room temperature to obtain the isocyanate prepolymer; The second polyol is selected from at least one of polyether polyols and polyester polyols; the polyether polyol is selected from one of S215H polyether polyol, polyether triol C310, and polyether tetraol F414. The plasticizer is selected from at least one of paraffin wax, asphalt, dioctyl terephthalate, plasticizer DOP, and plasticizer DIDP. The catalyst is dibutyltin dilaurate.

[0017] Preferably, the second filler is selected from at least one of cobalt blue, titanium dioxide, silica powder, and fumed silica.

[0018] This invention also provides a method for preparing a high-temperature resistant and aging-resistant polyurethane structural adhesive, comprising the following steps: (1) Mix the first polyol, flame retardant, reinforcing agent, triphenylphosphine and antioxidant, heat to 100℃-120℃, stir and dehydrate under vacuum for 1-3 hours, cool to 50-70℃; add to a mixer, then add polyurethane environmentally friendly organic bismuth catalyst BCAT-E20, thixotropic agent, molecular sieve and first filler, stir and react under vacuum to obtain component A; (2) Place the isocyanate prepolymer and the second filler in a mixer and stir under vacuum until homogeneous to obtain component B; (3) Mix component A and component B to obtain a high-temperature resistant and aging-resistant polyurethane structural adhesive.

[0019] The beneficial effects of this invention are: 1. This invention utilizes the interaction between various substances through reasonable proportioning and optimizes the preparation process to obtain a high-temperature resistant and aging-resistant polyurethane structural adhesive. The high-temperature resistant and aging-resistant polyurethane structural adhesive obtained by this invention can improve the toughness of products, has high tensile strength and heat resistance, and has excellent flame retardant properties.

[0020] 2. Compared with the prior art, the present invention uses hexadecylphenol-modified brominated epoxy resin obtained by reacting brominated epoxy resin with hexadecylphenol through a phenol-epoxy ring-opening addition reaction as a flame retardant. It may then interact further with the epoxy groups in the reinforcing agent structure during the mixing process, thereby enhancing the mechanical properties. During the mixing process of components A and B, the polyol in component A, the hexadecylphenol-modified brominated epoxy resin and the reinforcing agent all contain active structural energy that interacts with the isocyanate prepolymer, thereby significantly improving the impact resistance, interfacial bonding strength and heat aging resistance of the polyurethane structural adhesive. Detailed Implementation

[0021] The parameters and sources of some raw materials in this embodiment of the invention are as follows: Brominated epoxy resin: Model: EP-700, epoxy equivalent (g / eq): 350-3700, bromine content (%): 46-50, softening point 50-60℃, sourced from Jiangsu Xingsheng Chemical Co., Ltd. The environmentally friendly polyurethane organic bismuth catalyst BCAT-E20 is sourced from Guangzhou Yourun Synthetic Materials Co., Ltd. Hexadecylphenol: CAS No.: 5026-65-3; Molecular sieve: Model: 5A, Item No.: S14151, Specification: Spherical, 3-5mm, Source: Shanghai Yuanye Biotechnology Co., Ltd. Polyamide wax: Product number: PA97005, sourced from Guangdong Wengjiang Chemical Reagent Co., Ltd.; XCP-2000N polyester polyol: Grade: XCP-2000N, hydroxyl value (mgKOH / g) is 53-59, acid value (mgKOH / g) is 0.1-0.4, sourced from Asahikawa Chemical (Suzhou) Co., Ltd.

[0022] S215H polyether polyol: Grade: S215H, hydroxyl value (mgKOH / g) is 74±2, acid value (mgKOH / g) ≤0.05, sourced from Shandong Yinuowei New Materials Co., Ltd.

[0023] Example 1 A method for preparing a high-temperature resistant and aging-resistant polyurethane structural adhesive includes the following steps: (1) Mix 70 parts by mass of the first polyol, 15 parts by mass of the flame retardant, 10 parts by mass of the reinforcing agent, 0.03 parts by mass of the triphenylphosphine, and 0.5 parts by mass of the antioxidant 1010, heat to 110°C, stir and dehydrate under vacuum for 2 hours, and cool to 60°C; add to a mixer, and then add 0.03 parts by mass of the polyurethane environmentally friendly organic bismuth catalyst BCAT-E20, 2 parts by mass of polyamide wax, 5 parts by mass of molecular sieve, and 30 parts by mass of aluminum hydroxide. Stir under vacuum to obtain component A. (2) Place 80 parts by weight of isocyanate prepolymer and 30 parts by weight of silica powder in a mixer and stir under vacuum until homogeneous to obtain component B; (3) Mix component A and component B at a mass ratio of 1:1.1 to obtain a high-temperature resistant and aging-resistant polyurethane structural adhesive.

[0024] The first polyol is composed of S215H polyether polyol, XCP-2000N polyester polyol, and glycerol mixed in a mass ratio of 7:2.5:0.5.

[0025] The preparation method of the flame retardant includes the following steps: Mix 80 parts by weight of brominated epoxy resin, 65 parts by weight of hexadecylphenol and 0.5 parts by weight of antioxidant 1010, then heat to 100°C and add 0.5 parts by weight of triphenylphosphine. Continue heating to 140°C and react for 60 minutes to obtain hexadecylphenol modified brominated epoxy resin, i.e. flame retardant.

[0026] The preparation method of the reinforcing agent includes the following steps: Step 1: Under nitrogen protection, 40 parts by weight of 1,3,5,7-tetramethylcyclotetrasiloxane, 20 parts by weight of octamethylcyclotetrasiloxane, 10 parts by weight of 1,1,3,3-tetramethyldisiloxane, and 3 parts by weight of 0.3wt% trifluoromethanesulfonic acid were reacted at 25°C for 24 hours. Then, 30 parts by weight of sodium bicarbonate were added to the above reaction solution and stirred for 2 hours. The mixture was filtered, and the filtrate was collected to obtain hydrogen-containing polysiloxane. Step 2: Mix 45 parts by mass of 1,2-epoxy-4-vinylcyclohexane, 0.5 parts by mass of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, and 30 parts by mass of toluene until homogeneous. Then, purge the mixture with nitrogen gas and heat it to 85°C to obtain reaction solution 1. Mix 35 parts by mass of the hydrogen-containing polysiloxane obtained in Step 1 with 30 parts by mass of toluene and add the mixture dropwise to the above reaction solution 1. The addition is completed in 1.5 hours. Then, heat the mixture to 100°C and react for 12 hours. Remove the solvent to obtain the reinforcing agent.

[0027] The method for preparing the isocyanate prepolymer includes the following steps: 50 parts by mass of S215H polyether polyol and 3 parts by mass of dioctyl terephthalate were heated to 125°C and stirred under vacuum for 2 hours. The mixture was then cooled to 30°C, and diphenylmethane diisocyanate was added according to the stoichiometric ratio of 25% NCO content in the reaction system. 0.5 parts by mass of dibutyltin dilaurate were added, and the mixture was heated to 70°C and stirred under vacuum for 3 hours. The mixture was then cooled to room temperature to obtain the isocyanate prepolymer.

[0028] Example 2 A method for preparing a high-temperature resistant and aging-resistant polyurethane structural adhesive differs from Example 1 only in that the preparation method of the reinforcing agent includes the following steps: Step 1: Under nitrogen protection, 40 parts by weight of 1,3,5,7-tetramethylcyclotetrasiloxane, 20 parts by weight of octamethylcyclotetrasiloxane, 10 parts by weight of 1,1,3,3-tetramethyldisiloxane, and 3 parts by weight of 0.3wt% trifluoromethanesulfonic acid were reacted at 25°C for 24 hours. Then, 30 parts by weight of sodium bicarbonate were added to the above reaction solution and stirred for 2 hours. The mixture was filtered, and the filtrate was collected to obtain hydrogen-containing polysiloxane. Step 2: Mix 45 parts by weight of 3,4-epoxycyclohexyl methacrylate, 0.5 parts by weight of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, and 30 parts by weight of toluene until homogeneous. Then, purge with nitrogen for protection and heat to 85°C to obtain reaction solution 1. Mix 35 parts by weight of the hydrogen-containing polysiloxane obtained in Step 1 with 30 parts by weight of toluene until homogeneous and add dropwise to the above reaction solution 1. The addition is completed in 1.5 hours. Then, heat to 100°C and react for 12 hours. Remove the solvent to obtain the reinforcing agent.

[0029] Example 3 A method for preparing a high-temperature resistant and aging-resistant polyurethane structural adhesive differs from Example 1 only in that the preparation method of the reinforcing agent includes the following steps: Step 1: Under nitrogen protection, 40 parts by weight of 1,3,5,7-tetramethylcyclotetrasiloxane, 20 parts by weight of octamethylcyclotetrasiloxane, 10 parts by weight of 1,1,3,3-tetramethyldisiloxane, and 3 parts by weight of 0.3wt% trifluoromethanesulfonic acid were reacted at 25°C for 24 hours. Then, 30 parts by weight of sodium bicarbonate were added to the above reaction solution and stirred for 2 hours. The mixture was filtered, and the filtrate was collected to obtain hydrogen-containing polysiloxane. Step 2: Mix 45 parts by weight of 4-vinylphenyl glycidyl ether, 0.5 parts by weight of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, and 30 parts by weight of toluene until homogeneous. Then, purge with nitrogen for protection and heat to 85°C to obtain reaction solution 1. Mix 35 parts by weight of the hydrogen-containing polysiloxane obtained in Step 1 with 30 parts by weight of toluene until homogeneous and add dropwise to the above reaction solution 1. The addition is completed in 1.5 hours. Then, heat to 100°C and react for 12 hours. Remove the solvent to obtain the reinforcing agent.

[0030] Comparative Example 1 A method for preparing a high-temperature resistant and aging-resistant polyurethane structural adhesive, differing from Example 1 only in that the method for preparing the flame retardant includes the following steps: Mix 80 parts by weight of brominated epoxy resin and 0.5 parts by weight of antioxidant 1010, then heat to 100°C and mix evenly to obtain the flame retardant.

[0031] Comparative Example 2 A method for preparing a high-temperature resistant and aging-resistant polyurethane structural adhesive includes the following steps, in parts by weight: (1) Mix 70 parts by mass of the first polyol, 15 parts by mass of the flame retardant, 0.03 parts by mass of the triphenylphosphine, and 0.5 parts by mass of the antioxidant 1010, heat to 110°C, stir and dehydrate under vacuum for 2 hours, and cool to 60°C; add to a mixer, and then add 0.03 parts by mass of the polyurethane environmentally friendly organic bismuth catalyst BCAT-E20, 2 parts by mass of polyamide wax, 5 parts by mass of molecular sieve, and 30 parts by mass of aluminum hydroxide. Stir under vacuum to obtain component A. (2) Place 80 parts by weight of isocyanate prepolymer and 30 parts by weight of silica powder in a mixer and stir under vacuum until homogeneous to obtain component B; (3) Mix component A and component B at a mass ratio of 1:1.1 to obtain a high-temperature resistant and aging-resistant polyurethane structural adhesive.

[0032] The first polyol is composed of S215H polyether polyol, polyester polyol and glycerol mixed in a mass ratio of 7:2.5:0.5.

[0033] The preparation method of the flame retardant is the same as that in Example 1.

[0034] The preparation method of the isocyanate prepolymer is the same as that in Example 1.

[0035] Comparative Example 3 A method for preparing a high-temperature resistant and aging-resistant polyurethane structural adhesive includes the following steps: (1) Mix 70 parts by mass of the first polyol, 10 parts by mass of the reinforcing agent, 0.03 parts by mass of triphenylphosphine, and 0.5 parts by mass of antioxidant 1010, heat to 110°C, stir and dehydrate under vacuum for 2 hours, and cool to 60°C; add to a mixer, and then add 0.03 parts by mass of polyurethane environmentally friendly organic bismuth catalyst BCAT-E20, 2 parts by mass of polyamide wax, 5 parts by mass of molecular sieve, and 30 parts by mass of aluminum hydroxide. Stir and react under vacuum to obtain component A. (2) Place 80 parts by weight of isocyanate prepolymer and 30 parts by weight of silica powder in a mixer and stir under vacuum until homogeneous to obtain component B; (3) Mix component A and component B at a mass ratio of 1:1.1 to obtain a high-temperature resistant and aging-resistant polyurethane structural adhesive.

[0036] The first polyol is composed of S215H polyether polyol, polyester polyol and glycerol mixed in a mass ratio of 7:2.5:0.5.

[0037] The preparation method of the reinforcing agent is the same as that in Example 3.

[0038] The preparation method of the isocyanate prepolymer is the same as that in Example 1.

[0039] Test Example 1 Performance testing The high-temperature resistant and aging-resistant polyurethane structural adhesives obtained in Examples 1-3 and Comparative Examples 1-3 were tested for their corresponding properties according to the following standards: The shear strength was tested according to the standard GB / T 7124-2008 Determination of tensile shear strength of adhesives (rigid material to rigid material) The tensile strength and elongation at break were tested according to the standard GB / T 528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber. Flame retardancy was tested according to the standard "UL94 - Safety Standard for Flammability Testing of Plastic Components"; the test results are shown in Table 1.

[0040] Table 1 Performance Tests

[0041] A comparison of Examples 1-3 and Comparative Examples 1-3 reveals that Example 3 exhibits the best performance. This is likely because Example 3 incorporates a flame retardant and a reinforcing agent modified with 4-vinylphenyl glycidyl ether. The 4-vinylphenyl glycidyl ether modifier in Example 3 contains a conjugated large π-bond on a benzene ring. Grafting this onto the siloxane chain increases the rigidity of the crosslinking network, optimizes stress transfer, and improves mechanical properties. Its interaction with the hexadecylphenol-modified brominated epoxy resin further enhances flame retardancy. The modifier in Example 1, 1,2-epoxy-4-vinylcyclohexane, contains a cyclohexane backbone, resulting in lower interaction forces and crosslinking effects compared to Example 3. The modifier in Example 2, 3,4-epoxycyclohexyl methacrylate, contains alicyclic epoxy and ester groups, exhibiting better mechanical properties than Example 1 but less than Example 3.

[0042] Test Example 2 High temperature resistance test The high-temperature resistant and aging-resistant polyurethane structural adhesives obtained in Examples 1-3 and Comparative Examples 1-3 were cured and then exposed at 100°C for 500 hours. The tensile strength and elongation at break were then tested according to the standard GB / T 528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber. The test results are shown in Table 2.

[0043] Table 2 High Temperature Resistance Test

[0044] By comparing Examples 1-3 and Comparative Examples 1-3, it can be found that Example 3 has the best performance. The reason may be that the addition of flame retardant and 4-vinylphenyl glycidyl ether modified reinforcing agent in Example 3 can produce an interaction. The benzene ring in the brominated epoxy forms a π-π stack with the benzene ring of the reinforcing agent to form physical cross-linking points to resist thermal dissociation. The dynamic adaptability of the siloxane chain maintains high-temperature toughness and forms a physical cross-linking synergy with the benzene ring of the flame retardant. Finally, it still maintains structural integrity at 100°C.

Claims

1. A high-temperature resistant and aging-resistant polyurethane structural adhesive, characterized in that, It consists of two components, A and B, with a mass ratio of component A to component B of 1:0.8-1.2; Component A comprises the following raw materials in parts by weight: 50-90 parts of a first polyol, 20-40 parts of a first filler, 0.1-1.0 parts of an antioxidant, 1-3 parts of a thixotropic agent, 10-20 parts of a flame retardant, 5-15 parts of a reinforcing agent, 3-5 parts of a molecular sieve, 0.01-0.05 parts of a polyurethane environmentally friendly organic bismuth catalyst BCAT-E20, and 0.01-0.05 parts of triphenylphosphine; Component B comprises the following raw materials in parts by weight: 40-100 parts isocyanate prepolymer and 10-50 parts second filler; The flame retardant is a hexadecylphenol-modified brominated epoxy resin; The reinforcing agent is polydimethylsiloxane modified with vinyl compounds.

2. The high-temperature resistant and aging-resistant polyurethane structural adhesive as described in claim 1, characterized in that: The first polyol is composed of a mixture of polyether polyol, polyester polyol and glycerol; the polyether polyol is selected from one of S215H polyether polyol, polyether triol C310 and polyether tetraol F414.

3. The high-temperature resistant and aging-resistant polyurethane structural adhesive as described in claim 1, characterized in that: The first filler is selected from at least one of kaolin, mica powder, and aluminum hydroxide; the antioxidant is selected from at least one of antioxidant 1010, antioxidant 168, and antioxidant DLTP.

4. The high-temperature resistant and aging-resistant polyurethane structural adhesive as described in claim 1, characterized in that: The thixotropic agent is selected from at least one of bentonite and polyamide wax.

5. The high-temperature resistant and aging-resistant polyurethane structural adhesive as described in claim 1, characterized in that, The preparation method of the hexadecylphenol modified brominated epoxy resin includes the following steps, in parts by mass: Mix 50-100 parts of brominated epoxy resin, 50-80 parts of hexadecylphenol and 0.1-1 parts of antioxidant 1010, then heat to 80-120℃ and add 0.1-1.0 parts of triphenylphosphine, continue to heat to 120-160℃ and react for 30-90 minutes to obtain hexadecylphenol modified brominated epoxy resin.

6. The high-temperature resistant and aging-resistant polyurethane structural adhesive as described in claim 1, characterized in that, The preparation method of the reinforcing agent includes the following steps, in parts by mass: Step 1: Under nitrogen protection, react 30-50 parts of 1,3,5,7-tetramethylcyclotetrasiloxane, 10-30 parts of octamethylcyclotetrasiloxane, 5-15 parts of 1,1,3,3-tetramethyldisiloxane, and 1-5 parts of 0.3wt% trifluoromethanesulfonic acid aqueous solution at 20-30℃ for 20-30 h; then add 20-40 parts of sodium bicarbonate to the above reaction solution and stir for 1-3 h; filter, collect the filtrate, and obtain hydrogen-containing polysiloxane; Step 2: Mix 40-50 parts of modifier, 0.1-1 parts of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, and 20-40 parts of toluene evenly, then purge with nitrogen for protection, and then heat to 70-100℃ to obtain reaction solution 1; mix 25-40 parts of the hydrogen-containing polysiloxane obtained in Step 1 with 20-40 parts of toluene evenly and then add it dropwise to the above reaction solution 1, completing the addition in 1-3 hours, then heat to 80-120℃ and react for 10-14 hours; remove the solvent to obtain the reinforcing agent.

7. The high-temperature resistant and aging-resistant polyurethane structural adhesive as described in claim 6, characterized in that, The modifier is selected from at least one of 1,2-epoxy-4-vinylcyclohexane, 3,4-epoxycyclohexyl methacrylate, and 4-vinylphenyl glycidyl ether.

8. The high-temperature resistant and aging-resistant polyurethane structural adhesive as described in claim 1, characterized in that, The method for preparing the isocyanate prepolymer includes the following steps: 40-60 parts of the second polyol and 1-5 parts of the plasticizer are heated to 120-130℃ and stirred under vacuum for 1-3 hours; the temperature is then lowered to 25-40℃, and diphenylmethane diisocyanate is added according to the stoichiometric ratio of 10-30% NCO content in the reaction system. An appropriate amount of catalyst is added, the temperature is raised to 60-80℃, and the mixture is stirred under vacuum for 2-4 hours. The mixture is then cooled to room temperature to obtain the isocyanate prepolymer. The second polyol is selected from at least one of polyether polyols and polyester polyols, wherein the polyether polyol is selected from one of S215H polyether polyol, polyether triol C310, and polyether tetraol F414. The plasticizer is selected from at least one of paraffin wax, asphalt, dioctyl terephthalate, plasticizer DOP, and plasticizer DIDP. The catalyst is dibutyltin dilaurate.

9. The high-temperature resistant and aging-resistant polyurethane structural adhesive as described in claim 1, characterized in that, The second filler is selected from at least one of cobalt blue, titanium dioxide, silica powder, and fumed silica.

10. A method for preparing a high-temperature resistant and aging-resistant polyurethane structural adhesive as described in any one of claims 1-9, characterized in that, Includes the following steps: (1) Mix the first polyol, flame retardant, reinforcing agent, triphenylphosphine and antioxidant, heat to 100℃-120℃, stir and dehydrate under vacuum for 1-3 hours, cool to 50-70℃; add to a mixer, then add polyurethane environmentally friendly organic bismuth catalyst BCAT-E20, thixotropic agent, molecular sieve and first filler, stir and react under vacuum to obtain component A; (2) Place the isocyanate prepolymer and the second filler in a mixer and stir under vacuum until homogeneous to obtain component B; (3) Mix component A and component B to obtain a high-temperature resistant and aging-resistant polyurethane structural adhesive.

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